Most recent publications

• Torgersen, Gerald; Winsnes, Karianne Ervik; Handal, Trude; Diep, My Tien; Ørstavik, Dag Solmund & Sunde, Pia Titterud (2026). Open‐Weight Deep Learning for Periapical Index Scoring: Training and Comparison of Convolutional Neural Network Models Based on Three Distinct Architectures and an Ensemble Approach. International Endodontic Journal. ISSN 0143-2885. doi: 10.1111/iej.70268. Full text in Research Archive Show summary

  Aim This study aimed to (i) train and compare three convolutional neural network (CNN) architectures for Periapical Index (PAI) scoring on intraoral radiographs, and (ii) assess whether an ensemble of these models improves performance compared with any single architecture. Methods A dataset of 17,549 apex‐centred image clips extracted from intraoral radiographs was annotated by a calibrated observer (KW) with PAI scores (1–5) and used to train three CNN architectures (ResNet50, EfficientNet‐B3 and ConvNeXt‐Tiny) for PAI scoring. The image clips were split 80/20 into training and validation sets, and model selection was based on validation performance of quadratic weighted kappa (QWK). The three CNN models were combined into an equal‐weight soft‐voting ensemble model, and all four models were evaluated on an independent balanced test set of 200 images (40 per PAI score). QWK was used as the primary outcome metric, and bootstrapping was used to estimate the confidence intervals (CIs). The PAI scale was dichotomized into healthy (PAI 1–2) and diseased (PAI 3–5), and accuracy, sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and F1 score were calculated. Results The ensemble model achieved the highest performance with a QWK of 0.79 on the test set, followed by EfficientNet‐B3 (QWK = 0.77), ResNet50 (QWK = 0.76) and ConvNeXt‐Tiny (QWK = 0.70), with overlapping confidence intervals (CIs). For the binary PAI classification, the performance of the three CNN models and the ensemble model was comparable. The ensemble model achieved the following results: accuracy 86%, sensitivity 83%, specificity 90%, PPV 93%, NPV 78% and F1 score 0.88. Conclusion Optimization and evaluation of three CNN models and an ensemble model for PAI scoring showed comparable performance on both the five‐class PAI scale and the binary PAI scale on an independent test set. The ensemble model did not show statistically significant improvement over the three individual CNN architectures. The AI models trained and tested in this study are made open‐source under the open‐source MIT licence.

• Perez, Tamara; Portenier, Isabelle; Giannopoulou, Catherine & Zekeridou, Alkisti (2025). Health insurance and socioeconomic disparities in childhood caries. Swiss Dental Journal. ISSN 2296-6498. 135(4), p. 16–26. doi: 10.61872/sdj-2025-04-02. Full text in Research Archive Show summary

  Social inequalities are strongly associated with disparities in oral health, particularly in the development of childhood caries. This 4-year cohort study analyzed the impact of socioeconomic status (SES)- defined on the basis of the health insurance type- on the prevalence, treatment, and recurrence of dental caries in children. A total of 198 children (21 with social insurance, 177 with private insurance) were included. Caries prevalence at baseline was significantly higher in children with social insurance (95 % with >4 caries) compared to those with private insurance (29 % with >4 caries). No children with social insurance were caries-free, whereas 35 % of those with private insurance were caries-free. Pulpotomy and extraction needs were higher in the socially insured group, with 43 % requiring pulpotomies and 62 % requiring extractions, compared to 12 % and 10 %, respectively, in the privately insured group. General anesthesia (GA) use was more frequent in the socially insured group (72 % vs. 13 %), especially among younger children (100 % of 2-4 years old vs. 25 % in the private insurance group). In contrast, conventional anesthesia was more frequently used in the private insurance group (31 % vs. 14 %). Recall appointments were less frequent in the socially insured group, with 24% having no follow-up, compared to 12 % in the privately insured group. Caries recurrence was higher in the socially insured group (62 % had >3 new carious lesions) compared to the privately insured group, where 38 % of children had no new caries at follow-up. These findings highlight the impact of SES on caries burden, treatment modalities, and the importance of preventive measures for disadvantaged groups.

• Koutroulis, Andreas; Menon, Nandita; Kapralos, Vasileios; Ørstavik, Dag Solmund; Pain, Maria Ronessen & Valen, Håkon [Show all 9 contributors for this article] (2025). Investigation of the effect of addition/replacement of bioactive glass to hydraulic calcium silicate cement. Dental Materials. ISSN 0109-5641. 41(9), p. 1067–1079. doi: 10.1016/j.dental.2025.06.018. Full text in Research Archive Show summary

  Objectives Assess the effect of addition or replacement of bioactive glass (BG) on the physico-chemical, antibacterial and biological properties of radiopacified tricalcium silicate cement (TCS). Methods Four materials were tested: An experimental cement with 80 % TCS, 20 % zirconium oxide (TZ-base); two modified versions of TZ-base incorporating 20 % BG 45S5 either as TCS-replacement (TZ-bg-R) or addition (TZ-bg-A); and Biodentine (Septodont). Setting time was assessed using ISO 6876:2012 method. Materials were immersed in water or Dulbecco's modified eagle medium with 10 % fetal bovine serum (DMEM-sup). After seven days, water sorption and solubility were assessed using ISO 4049:2019 methods; water uptake and porosity were also calculated; leachate alkalinity and calcium release were assessed with a pH meter and inductively coupled plasma respectively; specimens were characterized with scanning electron microscopy, energy dispersive X-ray and X-ray diffraction analysis. At one-day, antibacterial properties of material surfaces and leachates were tested against Enterococcus faecalis and Staphylococcus epidermidis biofilms; leachate cytotoxicity and cytokine release were assessed with the 3-(4,5 dimethylthiazolyl-2-yl)-2,5-diphenyl tetrazolium bromide assay and an enzyme-linked immunosorbent assay. Regression models were fitted for all dependent variables. Results Compared to TZ-base, the BG-containing materials had overall increased water sorption, water uptake and porosity; decreased solubility in DMEM-sup; lower calcium release; and generally similar pH, antibacterial activity, cytotoxicity and cytokine release. All experimental cements were more cytotoxic than Biodentine, but the latter caused higher cytokine release. Significance The BG-incorporation whether added or replacing the cement decreased the solubility in clinically relevant media and did not deteriorate the antimicrobial and biological properties of the materials.

• Sunde, Pia Titterud; Giving, Erika Madeléne; Dilshad, Tabish; Handal, Trude & Ørstavik, Dag Solmund (2025). Radiographic Outcome of Endodontic Treatment of Teeth with Primary Apical Periodontitis: Results from a Postgraduate Clinic. Dentistry Journal. 13(12). doi: 10.3390/dj13120593. Full text in Research Archive
• Haug, Sivakami Rethnam; Virtej, Anca; Sunde, Pia Titterud & Fristad, Inge (2025). Ethical considerations and legal allegations in endodontic practice. European Journal of Oral Sciences. ISSN 0909-8836. 134(1). doi: 10.1111/eos.70043. Full text in Research Archive Show summary

  Endodontics is often cited as one of the leading dental disciplines involved in malpractice claims. This focus article aims to explore the ethical and legal aspects of endodontic treatment, with particular focus on identifying the underlying reasons for malpractice allegations, while highlighting the standard of care (SOC). A literature search was conducted to identify patterns in malpractice claims and adverse events related to endodontic treatment. Findings are organized into a clinically relevant classification of adverse events, as local, regional, or systemic, based on the location and response to injury. Not all adverse events result in negative outcomes, nor do they necessarily lead to litigation. Common dental malpractice claims often arise from diagnostic failures, lack of informed consent, deviation from SOC, and delays in referring patients when necessary. Allegations related to root perforation, lack of rubber dam usage, wrong tooth therapy, and infections have generally favored the plaintiffs. Ethical principles form a foundation for professional responsibility. Good communication, risk assessment, and record keeping are prerequisites to enforce patient safety and reduce the risk of malpractice. Targeted improvements in organizations, competence, resources, research, and education can ultimately benefit both patients and practitioners, ensuring higher SOCs and safety.

• Sunde, Pia Titterud; Skallevold, Hans Erling; Kaur, Manpreet & Ørstavik, Dag Solmund (2025). Changes in the Difficulty of Endodontic Cases Treated by Undergraduate Students at a University Clinic Between 1971 and 2019. Clinical and Experimental Dental Research. 11(1). doi: 10.1002/cre2.70071. Full text in Research Archive
• Katle, Erik; Zandi, Homan; Pedersen, Deniz; Sunde, Pia Titterud; Torgersen, Gerald R. & Ørstavik, Dag Solmund (2024). Radiographic outcome of endodontic treatment and retreatment of teeth with apical periodontitis using two different root canal irrigants. A prospective cohort study. International Endodontic Journal. ISSN 0143-2885. 57(3), p. 297–304. doi: 10.1111/iej.14019. Full text in Research Archive Show summary

  Aim The aim of this prospective cohort study was to compare the radiographic outcome of endodontic treatment and retreatment of teeth with apical periodontitis using either 1% sodium hypochlorite (NaOCl) or 2% chlorhexidine digluconate (CHX) for root canal irrigation. Materials and Methods In the years from 2013 to 2015 standard irrigation varied by semester between NaOCl and CHX at the Department of Endodontics at the Faculty of Dentistry. During that time, 912 teeth received treatment for apical periodontitis in 744 patients, of whom 532 responded to the request for a 1-year follow-up. Only one tooth per person (the most distally located) were included; 285 teeth treated with NaOCl and 247 with CHX. One hundred cases were then randomly sampled from each irrigation group and analysed for outcome by periapical index (PAI) scoring using criteria for success, uncertain and failure. Clinical and other radiographic parameters were scored or recorded and analysed for associations with radiographic outcome using chi-square, ANOVA and regression analyses. Results Success rates (PAI score 1 or 2 at control) were nearly identical for the two irrigation liquids. The use of irrigating solution also did not significantly influence the outcome in chi-square analyses of subgroups of teeth or regression analyses with other variables included. Ordinal regression analysis established that preoperative lesion size or preoperative PAI score were significantly associated with outcome, and teeth in the mandible had significantly better outcomes than in the maxilla. Conclusions No significant differences in the radiographic outcome using either 1% NaOCl or 2% CHX as irrigants were found. The outcome was better for teeth with small lesions or lower PAI scores at completion of treatment and for mandibular teeth.

• Koutroulis, Andreas; Kapralos, Vasileios; Ørstavik, Dag Solmund & Sunde, Pia Titterud (2024). Root-filling materials for endodontic surgery: biological and clinical aspect. Biomaterial Investigations in Dentistry. 11, p. 115–127. doi: 10.2340/biid.v11.42172. Full text in Research Archive Show summary

  The placement of root filling materials aims to prevent the occurrence of post-treatment apical periodontitis following completion of endodontic treatment. Materials should possess properties that will not permit bacterial invasion and infection, namely excellent sealing ability and/or antibacterial properties. In root-end filling procedures or repair of root perforations, the root filling materials are placed in a particularly challenging clinical environment, as they interface with a relatively large area with the periradicular tissues. The biological properties of these materials are therefore of significant importance. The current review discusses the most widely used materials for endodontic surgery (i.e., root-end filling and perforation repair), with particular focus on their biological characteristics, namely antibacterial properties and interactions with host tissue cells, together with clinical studies. Properties of amalgam, glass ionomer cements (GICs), resin systems, zinc oxide eugenol-based cements and hydraulic calcium silicate cements (HCSCs), together with representative and well-researched commercial materials in the context of their use in endodontic surgery are presented. While the use of HCSCs seems to offer several biological advantages, together with addressing issues with the initial formulation in the most recent versions, materials with different chemical compositions, such as zinc oxide eugenol-based cements, are still in use and appear to provide similar clinical success rates to HCSCs. Thus, the significance of the currently available materials on clinical outcomes remains unclear.

• Sødal, Anne Thea Tveit; Diep, My Tien; Skudutyte-Rysstad, Rasa; Singh, Preet Bano; Young, Alix & Jensen, Janicke Liaaen [Show all 9 contributors for this article] (2024). Oral helse blant 65-åringer i Oslo. Den norske tannlegeforenings Tidende. ISSN 0029-2303. 12(134). doi: 10.56373/2024-12-5. Full text in Research Archive
• Kapralos, Vasileios; Camilleri, Josette; Koutroulis, Andreas; Valen, Håkon; Ørstavik, Dag Solmund & Sunde, Pia Titterud (2023). Endodontic sealers after exposure to chlorhexidine digluconate: An assessment of physicochemical properties. Dental Materials. ISSN 0109-5641. doi: 10.1016/j.dental.2023.11.019. Full text in Research Archive Show summary

  Objectives Final root canal irrigation should ideally maintain the physicochemical stability of root canal sealers. We seek to assess the effect of contact with 2% chlorhexidine digluconate (CHX) on the physicochemical properties of AH Plus, BioRoot™ RCS, and Pulp Canal Sealer (PCS). Methods Mixed sealers were placed in cylindrical teflon molds and allowed to set for 1.5x the manufacturers’ setting time. Half of the specimens had their free surface in contact with CHX for the first minute of their setting period. Solubility, radiopacity, surface roughness, microhardness and wettability of the sealers were assessed up to 28 days after setting. Elemental analysis of sealer surfaces and their leachates together with pH measurements were also performed. Appropriate parametric and non-parametric analysis with post hoc tests were performed (p < 0.05). Results Exposure to CHX had no effect on solubility and radiopacity of all sealers. CHX altered the surface roughness of PCS and BioRoot RCS (p < 0.05). Contact with CHX reduced the microhardness of AH Plus and PCS (p < 0.05). AH Plus was more hydrophilic after CHX contact, whereas PCS became more hydrophobic (p < 0.05). AH Plus and PCS surfaces appeared to adsorb CHX as exhibited by chlorine peaks after contact with CHX. Sealer leachates’ alkalinity was not affected. CHX increased elution of silicon and zirconium for BioRoot and zinc for PCS leachates. Significance In our study, CHX affected sealers’ physicochemical properties to various extents. Further studies are needed to confirm the obtained results by investigating various final irrigation strategies and correlating to biological properties.

• Koutroulis, Andreas; Valen, Håkon; Ørstavik, Dag Solmund; Kapralos, Vasileios; Camilleri, Josette & Sunde, Pia Titterud (2023). Effect of exposure conditions on chemical properties of materials for surgical endodontic procedures. European Journal of Oral Sciences. ISSN 0909-8836. 131(4). doi: 10.1111/eos.12943. Full text in Research Archive Show summary

  Abstract This study investigated the role of aging and changes in environmental conditions on selected properties of a prototype radiopacified calcium silicate‐based cement (TZ‐base) with or without incorporation of silver nanoparticles or bioactive glass, and two commercial materials, Biodentine and intermediate restorative material. Materials were immersed in ultrapure water or fetal bovine serum for 28 days and were characterized with scanning electron microscopy and energy dispersive x‐ray analysis. Immersion media were either replaced weekly or not replenished at all and were assessed for alkalinity and calcium release after 1, 7, 14, 21, and 28 days; antibacterial effect against 2‐day monospecies biofilms; and cytotoxicity by the 3‐(4,5 dimethylthiazolyl‐2‐yl)‐2,5‐diphenyl tetrazolium bromide assay after 1, 7, or 28 days. Alkalinity, calcium release, antibacterial activity, and cell cytotoxicity increased over time when the medium was not changed but decreased with medium replenishment. Immersion in fetal bovine serum resulted in lower alkalinity, less bactericidal properties, and lower cytotoxicity of prototype cements and Biodentine than did water immersion. Biodentine and 20% bioactive glass‐containing cement had overall lower alkalinity, calcium release, and antibacterial activity than TZ‐base, and Biodentine was less cytotoxic than TZ‐base. In conclusion, exposure conditions and cement modifications significantly affected materials’ leaching properties. Exposure conditions warrant consideration when evaluating cements’ clinical properties.

• Agger, Anne Eriksson; Reseland, Janne Elin; Hjelkrem, Erik; Lian, Aina-Mari; Hals, Else Kristine Breivik & Zandi, Homan [Show all 7 contributors for this article] (2023). Are comorbidities associated with the cytokine/chemokine profile of persistent apical periodontitis? Clinical Oral Investigations. ISSN 1432-6981. 27, p. 5203–5215. doi: 10.1007/s00784-023-05139-3. Full text in Research Archive
• Virtej, Anca; Wigsten, Emma; Ørstavik, Dag Solmund & Haug, Sivakami Rethnam (2023). Utvikling av endodontien i fremtiden. Den norske tannlegeforenings Tidende. ISSN 0029-2303. doi: 10.56373/2023-2-8. Full text in Research Archive
• Astudillo-Ortiz, Esteban; Babo, Pedro S.; Sunde, Pia Titterud; Galler, Kerstin M.; Gomez-Florit, Manuel & Gomes, Manuela E. (2023). Endodontic Tissue Regeneration: A Review for Tissue Engineers and Dentists. Tissue Engineering Part B: Reviews. ISSN 1937-3368. 29(5), p. 491–513. doi: 10.1089/ten.teb.2022.0211. Full text in Research Archive
• Stueland, Håvard; Ørstavik, Dag Solmund & Handal, Trude (2023). Treatment outcome of surgical and non-surgical endodontic retreatment of teeth with apical periodontitis. International Endodontic Journal. ISSN 0143-2885. 56(6), p. 686–696. doi: 10.1111/iej.13914. Full text in Research Archive
• Koutroulis, Andreas; Valen, Håkon; Ørstavik, Dag Solmund; Kapralos, Vasileios; Camilleri, Josette & Sunde, Pia Titterud (2023). Antibacterial Activity of Root Repair Cements in Contact with Dentin—An Ex Vivo Study. Journal of Functional Biomaterials. 14(10). doi: 10.3390/jfb14100511. Full text in Research Archive Show summary

  This study assessed the antibacterial characteristics of the dentin/material interface and dentin surfaces exposed to experimental hydraulic calcium silicate cement (HCSC) with or without bioactive glass (BG) replacement (20% or 40%) or mixed with a silver nanoparticle (SNP) solution (1 or 2 mg/mL), and Biodentine, TotalFill BC RRM putty and Intermediate Restorative Material (IRM). Human root dentin segments with test materials were assessed at 1 or 28 days. In one series, the specimens were split to expose the dentin and material surfaces. A 24 h direct contact test was conducted against three-day established Enterococcus faecalis and Pseudomonas aeruginosa monospecies biofilms. In another series, the dentin/material interface of intact specimens was exposed to biofilm membranes for 3 days and the antibacterial activity was assessed via confocal microscopy. The interface was additionally characterised. All one-day material and dentin surfaces were antibacterial. Dentin surfaces exposed to HCSC with 40% BG-replacement, Biodentine and IRM had decreased antibacterial properties compared to those of the other cements. The HCSC mixed with a 2 mg/mL SNP solution had the highest antimicrobial effect in the confocal assay. The interfacial characteristics of HCSCs were similar. The test materials conferred antibacterial activity onto the adjacent dentin. The BG reduced the antibacterial effect of dentin exposed to HCSC; a 2 mg/mL SNP solution increased the antibacterial potential for longer interaction periods (three-day exposure).

• Kapralos, Vasileios; Sunde, Pia Titterud; Camilleri, Josette; Morisbak, Else; Koutroulis, Andreas & Ørstavik, Dag Solmund [Show all 7 contributors for this article] (2022). Effect of chlorhexidine digluconate on antimicrobial activity, cell viability and physicochemical properties of three endodontic sealers. Dental Materials. ISSN 0109-5641. 38(6), p. 1044–1059. doi: 10.1016/j.dental.2022.04.013. Full text in Research Archive Show summary

  Objective Assess the biological and physicochemical properties of AH Plus, BioRoot RCS and Pulp Canal Sealer (PCS) leachates with and without chlorhexidine (CHX). Methods The sealers were studied in no contact and 1-minute contact with CHX. For biological properties (antibacterial activity and cytotoxicity), leachates were formed in saline of freshly mixed, 1-, 7- and 28 days set sealers. The antibacterial properties of sealer leachates were investigated for planktonic and biofilm growth of E. faecalis, S. mutans, S.epidermidis and S.aureus. The 3-(4,5 dimethylthiazolyl-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay was used to evaluate murine fibroblast cell viability after exposure to the leachates. The physical properties (water uptake, sorption, solubility, porosity, surface characteristics) of sealers and the pH of the immersion liquid (saline or distilled water) were also assessed over a 28-days period. Results CHX improved the antibacterial properties of the sealer leachates and reduced cell viability for all sealer leachates, except for freshly mixed PCS. BioRoot RCS leachates presented the highest antibacterial properties and cell viability with and without CHX contact. PCS was the material most affected by CHX in terms of physical properties, whereas for AH Plus, solubility was increased. CHX did not affect the physical properties of BioRoot RCS, except for solubility that was decreased. CHX contact did not change sealers’ alkalinity in distilled water whereas it increased it for AH Plus and BioRoot RCS in saline. Significance CHX improved the antibacterial efficacy of sealer leachates and either compromised or did not affect cell viability. CHX affected to various extent sealers’ physicochemical properties.

• Koutroulis, Andreas; Valen, Håkon; Ørstavik, Dag Solmund; Kapralos, Vasileios; Camilleri, Josette & Sunde, Pia Titterud (2022). Surface characteristics and bacterial adhesion of endodontic cements. Clinical Oral Investigations. ISSN 1432-6981. 26, p. 6995–7009. doi: 10.1007/s00784-022-04655-y. Full text in Research Archive Show summary

  Abstract Objectives To investigate the effect of inclusion of silver nano-particles (SNP) or bioactive glass (BG) on the surface characteristics and bacterial adhesion of prototype tricalcium silicate (TCS)–based cements alongside two commercial cements, under different aging periods and exposure conditions. Materials and methods A basic formulation of radio-opacified TCS without (TZ-base) and with additions of SNP (0.5, 1, or 2 mg/ml) or BG (10 or 20%) was used. Biodentine and intermediate restorative material (IRM) served as reference materials. Material disks were immersed in ultrapure water or fetal bovine serum (FBS) for 1, 7, or 28 days. Surface roughness ( n  = 3), microhardness ( n  = 9), and wettability ( n  = 6) were analyzed by standard procedures. Adhesion of Enterococcus faecalis was assessed by fluorescence microscopy ( n  = 5). Data from these assays were evaluated for normality and comparisons among groups were conducted with statistical procedures ( p  &lt; 0.05 for significance). Results The surface morphology of SNP- and BG-containing cements had higher roughness values than TZ-base after 28 days ( p  &lt; 0.05). No differences in microhardness were observed among prototype cements ( p  &gt; 0.05). Biodentine presented smooth surface characteristics and the highest hardness values ( p  &lt; 0.05). The FBS-immersion resulted in surface reactions in prototype materials and Biodentine, depicted with scanning electron microscopy. All 1- and 7-day prototype cements showed negligible bacterial adhesion, while in Biodentine and IRM, noticeable E. faecalis adherence was observed from day 1 ( p  &lt; 0.05). Conclusions Incorporation of SNP or BG did not improve the antibacterial effect of the experimental cement; all 28-day aged materials failed to inhibit bacterial adherence. The measured physical parameters did not appear to be related to the degree of bacterial adhesion. Exposure of TCS-based cements in FBS resulted in surface reactions, which did not affect bacterial adhesion. Clinical relevance Changes in the surface characteristics of prototype TCS-based cements by inclusion of SNP and BG or exposure to different environments did not affect bacterial adhesion. All experimental materials showed inferior physical properties and higher antibacterial effect than Biodentine.

• Hæreid, Marika Koutsouri; Stangvaltaite-Mouhat, Lina; Ansteinsson, Vibeke Elise; Mdala, Ibrahimu & Ørstavik, Dag Solmund (2022). Periapical status transitions in teeth with posts versus without posts: a retrospective longitudinal radiographic study. Acta Odontologica Scandinavica. ISSN 0001-6357. doi: 10.1080/00016357.2022.2049865. Full text in Research Archive Show summary

  Objectives The aim of this study was to compare periapical status transitions in teeth after post placement compared with other post-endodontic treatments in root-filled teeth. Material and methods This retrospective longitudinal radiographic study included radiographs of 284 patients with root filled and restored teeth with composite fillings (Endo-fill group, n = 100), crown or fixed prosthesis (Endo-crown group, n = 82) or post and core restorations (Endo-post group, n = 102). All post and core restorations were made of gold alloy. The radiographs taken at the end of endodontic treatment, at the end of post-endodontic treatment and at least 8 months after post-endodontic treatment were evaluated. Post-operative periapical status was assessed according to the periapical index (PAI) and all teeth included in the study had no apical periodontitis preoperatively. Multi-state Markov analysis was used to assess periapical status transitions among the treatment groups. Results Of 284 root-filled teeth without apical periodontitis at baseline, 7.7% developed clear apical pathology within a minimum of 8 months observational period. In the Endo-post group 11 (10.78%) teeth transited from Healthy (PAI 1) to Disease (PAI 2-4) state compared with eight (9.75%) in the Endo-crown group and four (4%) in the Endo-fill group. The transition probabilities from Healthy (PAI 1) to Mild diseased (PAI 2) were 17.5% in the Endo-post group, 13.1% in the Endo-crown group and 5.3% in the Endo-fill group. Multivariate analysis showed that teeth in the Endo-fill group had 60% lower hazard to transit from Healthy (PAI 1) to Mild diseased (PAI 2) state [HR 0.40; 95% CI 0.12, 0.94]. A period exceeding 8 months between the end of the endodontic treatment and prosthetic treatment significantly increased the hazard of disease progression by three times compared with a period of ≤8 months [HR 3.16; 95% CI 1.06, 9.42]. Conclusions Teeth without radiographic lesions at baseline and restored with posts had higher hazard to transit from healthy to diseased periapical status compared with teeth restored with composite restorations. Controlled clinical trials with longer follow-up periods are needed to validate these findings.

• Kapralos, Vasileios; Valen, Håkon; Koutroulis, Andreas; Camilleri, Josette; Ørstavik, Dag Solmund & Sunde, Pia Titterud (2022). The dentine-sealer interface: Modulation of antimicrobial effects by irrigation. International Endodontic Journal. ISSN 0143-2885. 55(5), p. 544–560. doi: 10.1111/iej.13692. Full text in Research Archive Show summary

  Aim Assess whether sodium hypochlorite (NaOCl) or chlorhexidine (CHX) and two irrigation protocols may alter the antibacterial properties of dentine and three endodontic sealers using a novel ex vivo tooth model. Methodology Prior to antibacterial testing, the tooth model was validated by means of scanning electron microscopy (SEM) to evaluate the separation between dentine and sealer surfaces. Root blocks prepared from extracted human roots were pre-treated with 17% EDTA + 0.9% saline and subsequently treated with 1% NaOCl (G1), 2% CHX (G2) or no irrigant (G3). Two irrigation protocols were further investigated, “1% NaOCl + 17% EDTA” (P1) and “1% NaOCl + 17% EDTA + 2% CHX” (P2). Following irrigation, the root blocks were either filled with AH Plus, BioRoot RCS and Pulp Canal Sealer (PCS), or left empty. All groups were incubated for 1, 7 and 28 days. Direct contact tests for planktonic E. faecalis and 48 h E. faecalis biofilms were performed at the level of dentine and sealer surfaces. Statistical analysis was performed on the bacterial survival between irrigants (G1, G2 and G3) and between irrigation protocols (P1 and P2); p < .05. Results The model was considered reproducible as SEM examination of dentine samples indicated consistent separation between dentine and sealer surfaces. Irrigation with CHX (G2) and irrigation protocol P2 enhanced the antibacterial properties of dentine without sealer application as well as dentine in contact with all three sealers tested, especially against planktonic E. faecalis. G2 and P2 also improved the antibacterial effect of AH Plus surfaces for all three incubation times. No irrigation groups (G1, G2) or irrigation protocols (P1, P2) altered the antibacterial properties of BioRoot RCS surfaces against planktonic bacteria or biofilms. Only BioRoot RCS surfaces eliminated the planktonic E. faecalis in all irrigation groups (G1, G2, G3) and protocols (P1, P2) investigated whilst PCS surfaces eliminate E. faecalis in biofilms in all groups up to 7 days. Conclusions The tooth model was reproducible. CHX improved the antibacterial activity upon both sealer and dentine surfaces. Amongst sealers, BioRoot RCS was less affected by NaOCl and CHX, and exhibited high antibacterial properties regardless the irrigation applied.

• Diep, My Tien; Hove, Lene Hystad; Ørstavik, Dag Solmund; Skudutyte-Rysstad, Rasa; Sødal, Anne Thea Tveit & Sunde, Pia Titterud (2022). Periapical and endodontic status among 65-year-old Oslo-citizens. BMC Oral Health. 22(1). doi: 10.1186/s12903-022-02406-9. Full text in Research Archive Show summary

  Aim This cross-sectional study aimed to investigate the prevalence of apical periodontitis (AP) and root-filled teeth in a 65-year-old population in Oslo, Norway, and to investigate associations of pathosis and endodontic treatment with selected individual risk indicators and technical quality of root fillings. Material and methods A random sample of 450 65-year-olds in Oslo answered a questionnaire and underwent a clinical and radiological examination (52% men and 48% women). Periapical radiographs were taken of all root-filled teeth and of teeth with apical radiolucency, and periapical status was evaluated using the Periapical Index. Apex-to-filling distance and homogeneity were assessed for all root fillings. Analyses on individual level and tooth level were performed. The outcome variables were ‘non-root-filled tooth with AP’ (‘untreated AP’), ‘root-filled tooth’, and 'root-filled tooth with AP’. The explanatory variables were gender, education, dental attendance pattern, smoking, remaining teeth (n), tooth group, and root filling quality. Chi-square test and logistic regression analyses were used to assess the associations between outcome variables and explanatory variables. The level of significance was set to p < 0.05. Results The mean number of remaining teeth was 26 (SD: 4). AP was present in 45% of the individuals. Sixteen percent of the individuals had untreated AP and 38% had at least one root-filled tooth with AP. Sixty-six percent of the individuals had one or more root-filled teeth. Untreated AP was significantly associated with a decreasing number of remaining teeth and smoking. All the outcome variables were significantly more prevalent in molars compared with premolars and anterior teeth. Thirty-five percent of the root-filled teeth had AP, and AP was more prevalent in teeth with too short apex-to-filling distance (53%) or unsatisfactory homogeneity (46%). Conclusions The remaining number of teeth was high, and AP and root-filled teeth were prevalent in the present young-elderly population. A notable amount of untreated AP was observed, especially in smokers. The findings in the present study indicate a substantial need for dental care associated with endodontic conditions in the future elderly.

• Jordal, Kristin; Skudutyte-Rysstad, Rasa; Sen, Abhijit; Torgersen, Gerald; Ørstavik, Dag & Sunde, Pia Titterud (2021). Effects of an individualized training course on technical quality and periapical status of teeth treated endodontically by dentists in the Public Dental Service in Norway. An observational intervention study. International Endodontic Journal. ISSN 0143-2885. doi: 10.1111/iej.13669. Full text in Research Archive Show summary

  Aim: To investigate the effect of a continuing education course on technical quality and treatment outcome for root filled permanent teeth in Møre and Romsdal County, Norway. Methodology: Fifty-two dentists employed in the Public Dental Service in Møre and Romsdal county, Norway, completed a two-day continuing education course in root canal treatment. Periapical radiographs of root filled teeth treated before and after the course, with at least one-year follow-up were identified and scored for technical quality and periapical status. Technical root filling quality was assessed by density and length and the treatment outcome by PAI scores. Treatment information was achieved from the county's electronic dental record system. Information regarding the dental practitioners' background and treatment procedure routines was collected by a questionnaire. Descriptive statistics analyses and mixed-effect logistic regression analyses were performed to evaluate the effect of the course. Results: Radiographs were available for 224 teeth root filled before and for 221 teeth after the course. The proportion of teeth with adequate root filling quality was significantly lower after the course (p =0.006), associated mainly with short root fillings (p 18 years. Conclusions: A two-day continuing education course in root canal treatment attended by Public Dental Service dentists in Norway did not improve the technical quality of root fillings or periapical status associated with root filled teeth. Keywords: apical periodontitis; continuing education; endodontics; general dental practitioner; reciprocating technique; root filling quality.

• Jordal, Kristin; Sen, Abhijit; Skudutyte-Rysstad, Rasa; Ørstavik, Dag & Sunde, Pia Titterud (2021). Effects of an individualised training course in endodontics on the knowledge and insights of dentists in Public Dental Service in Norway. Acta Odontologica Scandinavica. ISSN 0001-6357. doi: 10.1080/00016357.2021.1876915. Full text in Research Archive Show summary

  Objective To evaluate the knowledge and insights of general dental practitioners regarding endodontic diagnosis and treatment principles before and after attending a 2-days continuing education course. Materials and methods Sixty-seven dentists employed in the Public Dental Service in Møre and Romsdal county, Norway, were invited to a continuing education course in endodontics. Before and after the course, they answered a questionnaire weighing the importance of factors influencing the prognosis of endodontic treatment. The same questionnaire was answered by specialists in endodontics (n = 56; Spec Group) and a reference group consisting of general dental practitioners from both private and public practice (n = 21; Ref Group). The Test Group answered both before and after the course, while the Spec and Ref Groups completed the questionnaire once. The responses were compared using the Wilcoxon Sign test and Mann–Whitey U test. Results Of the 67 dentists in the Test Group, 49 (73%) completed the course and answered both questionnaires. Before attending the course, the Test Group differed significantly from the Spec Group in 18 out of 27 prognostic factors (p ≤ .05). After the course, there was only moderate improvement in the Test Group responses. On only three factors, they agreed significantly more with the specialists than before attending the course (p ≤ .05). After the Test Group participants had attended the course, their responses were comparable to the responses of the Ref Group.

• Torben, Hildebrand; Nogueira, Liebert Parreiras; Sunde, Pia Titterud; Ørstavik, Dag; Glasmacher, Birgit & Haugen, Håvard Jostein (2021). Contrast-enhanced nano-CT reveals dental soft tissues and cellular layers. International Endodontic Journal. ISSN 0143-2885. 54(8), p. 1275–1288. doi: 10.1111/iej.13527. Full text in Research Archive Show summary

  Aim: Nano-CT technologies offer 3D imaging methods that allow high-resolution examination of bones and teeth, but soft tissue components have weak X-ray attenuation and are not easily visualised in CT images. We introduce a methodology designed to simultaneously visualise dental ultrastructure, including cellular and soft tissue components, by utilising phosphotungstic acid (PTA) as a contrast-enhancement agent. Methodology: Sound third molars were collected from healthy human adults and fixed in 4% buffered paraformaldehyde. To evaluate the impact of PTA in concentrations of 0.3%, 0.7% and 1% on dental soft and hard tissues for CT imaging, cementum and dentine-pulp sections were cut, dehydrated and stained with immersion periods of 12 hours, 24 hours, 2 days or 5 days. The samples were scanned with high-resolution nano-CT, where we examined both the cementum and pulpal regions with pixel sizes down to 0.5 µm for dental-pulp sections. Results: Dental cementum and periodontium as well as odontoblasts and predentine were made visible through PTA-staining in high-resolution three-dimensional nano-CT scans. Different segments of the tooth required different staining protocols. The thickness of the cementum could be computed over the height of the tooth once it was made visible by the PTA-enhanced contrast, and the attached soft tissue components of the interior of the tooth could be shown on the dentine-pulp interface in greater detail. Three-dimensional illustrations allowed a histology-like visualisation of the sections in all orientations with a single scan and easy sample preparation. The segmentation of the sigmoidal dentinal tubules and the surrounding dentine allowed a three-dimensional investigation and quantative of the dentine composition, such as the tubular lumen or the ratio of the tubular lumen area to the dentinal surface. Conclusion: The staining protocol made it possible to visualise hard tissues along with cellular layers and soft tissues using a laboratory-based nano-CT technique. The protocol depended on both tissue type and size. This methodology offers enhanced possibilities for the concomitant visualisation of soft and hard dental tissues.

• Nagendrababu, Venkateshbabu; Chong, Bunsan; McCabe, Paul S.; Shah, Pratik K.; Priya, Ekta & Jayaraman, Jayakumar [Show all 10 contributors for this article] (2020). PRICE 2020 guidelines for reporting case reports in Endodontics: a consensus-based development. International Endodontic Journal. ISSN 0143-2885. 53, p. 619–626. doi: 10.1111/iej.13285. Full text in Research Archive
• Døving, Mats; Handal, Trude & Galteland, Pål (2020). Bakterielle odontogene infeksjoner. Tidsskrift for Den norske legeforening (Tidsskriftet). ISSN 0029-2001. doi: 10.4045/tidsskr.19.0778. Full text in Research Archive
• Kapralos, Vasileios; Valen, Håkon; Ørstavik, Dag; Koutroulis, Andreas; Camilleri, Josette & Sunde, Pia Titterud (2020). Antimicrobial and physicochemical characterization of endodontic sealers after exposure to chlorhexidine digluconate. Dental Materials. ISSN 0109-5641. doi: 10.1016/j.dental.2020.11.011. Full text in Research Archive
• Knudsen, Dyveke; Ottersen, Margareth Kristensen; Ørstavik, Dag & Sunde, Pia Titterud (2019). Multiple idiopatiske cervikale rotresorpsjoner - forekomst og kasuistikker. Den norske tannlegeforenings Tidende. ISSN 0029-2303. 129(4), p. 342–351. Full text in Research Archive
• Koutroulis, Andreas; Batchelor, Hannah; Kuehne, Sarah A; Cooper, Paul R & Camilleri, Josette (2019). Investigation of the effect of the water to powder ratio on hydraulic cement properties. Dental Materials. ISSN 0109-5641. doi: 10.1016/j.dental.2019.05.011. Full text in Research Archive
• Zandi, Homan; Petronijevic, Nikola; Mdala, Ibrahimu; Kristoffersen, Anne Karin; Enersen, Morten & Rocas, Isabela N. [Show all 8 contributors for this article] (2019). Outcome of endodontic retreatment Using 2 root canal irrigants and influence of infection on healing as determined by a molecular method: A Randomized Clinical Trial. Journal of Endodontics. ISSN 0099-2399. 45(9), p. 1089–1098.e5. doi: 10.1016/j.joen.2019.05.021. Full text in Research Archive
• Hardersen, Line Rørslett; Enersen, Morten; Kristoffersen, Anne Karin; Ørstavik, Dag & Sunde, Pia Titterud (2019). Maintenance of the aseptic working field during endodontic treatment. Acta Odontologica Scandinavica. ISSN 0001-6357. p. 1–6. doi: 10.1080/00016357.2019.1606935. Full text in Research Archive Show summary

  ABSTRACT Objective: The aim of this clinical quality study was to determine whether the aseptic working field is maintained during the endodontic procedure. Materials and methods: Bacterial samples were collected from the rubber dam of 27 patients during endodontic treatment performed by postgraduate students at the Department of Endodontics, University of Oslo. A bacterial sample was first obtained immediately after disinfection of the working field (A), and the second sample was collected just before obturation or dressing with calcium hydroxide cement (B). Aerobic cultivation technique and PCR were used for detection of bacterial growth and species. Results: All samples were negative on culturing except in one case, which showed positive results with cultivation in both sample A and B. Specie detected with cultivation technique were Streptococcus mitis. With PCR technique, 6 samples in 5 patients (11%), showed positive results. Species detected with PCR technique were Bacteroidales spp. Propionibacterium spp., Bacteroidetes spp., Prevotella nigrescens, Haemophilus parainfluenzae, Neisseria elongata, Alloprevotella tannerae, Capnocytophaga granulosa, Cardiobacterium hominis, Fusobacterium nucleatum and Streptococcus mitis. Conclusion: The present study showed that an aseptic working field was maintained throughout the endodontic procedure in 81% (22/27) of the cases after disinfection of the rubber dam.

• Endal, Unni; Shen, Ya; Ma, Jingzhi; Yang, Yan & Haapasalo, Markus (2018). Evaluation of Quality and Preparation Time of Retrograde Cavities in Root Canals Filled with GuttaCore and Cold Lateral Condensation Technique. Journal of Endodontics. ISSN 0099-2399. 44(4), p. 639–642. doi: 10.1016/j.joen.2017.11.023. Full text in Research Archive
• Zandi, Homan; Kristoffersen, Anne Karin; Ørstavik, Dag; Rocas, Isabela; Siqueira, Jose F. & Enersen, Morten (2018). Microbial Analysis of Endodontic Infections in Root-filled Teeth with Apical Periodontitis before and after Irrigation using Pyrosequencing. Journal of Endodontics. ISSN 0099-2399. 44(3), p. 372–378. doi: 10.1016/j.joen.2017.11.019. Full text in Research Archive
• Johnsen, Gaute Floer; Sunde, Pia Titterud & Haugen, Håvard Jostein (2018). Validation of contralateral premolars as the substrate for endodontic comparison studies. International Endodontic Journal. ISSN 0143-2885. 51(8), p. 942–951. doi: 10.1111/iej.12902. Full text in Research Archive Show summary

  AIM: To use micro-CT technology and metrology software to validate the use of contralateral premolars as samples in endodontic comparison studies by comparing them before and after canal instrumentation with one instrumentation system. Furthermore, to determine if contralateral premolar roots will yield non-significantly different outcomes regarding shaping ability (volume), degree of twisting, and three-dimensional shape changes. The null-hypothesis (H0 ) is that there are no differences between the contralateral premolar roots pre- or post-instrumentation. METHODOLOGY: Twenty-eight extracted human contralateral premolars (n=44 contralateral roots) from 12 donor patients were scanned with microcomputed tomography before and after instrumentation. Root canal lengths (RCL) were measured visually using a dental operating microscope, electronic apex locator, and micro-CT scans. Data were analyzed statistically for differences between pre- and post-instrumentation. RESULTS: Instrumentation increased the volume of the canals significantly (P<0.05). Degree of twisting for a majority (83%) of the contralateral roots pairs did not change significantly (P>0.05). There was no significant difference (P>0.05) in the shape deviation analysis between contralateral pairs. There was no significant difference (P>0.05) for root canal length between the contralateral pairs for any of the three endometric methods. CONCLUSION: Contralateral premolar root canals were associated with similar changes in terms of volume, three-dimensional shape, and degree of twisting from pre- to post-instrumentation. There was no difference between the contralateral premolar root pairs pre- and post-instrumentation, and the study validates contralateral premolars as samples for root canal comparison studies. The null-hypothesis (H0 ) could not be rejected. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

• Kapralos, Vasileios; Koutroulis, Andreas; Ørstavik, Dag; Sunde, Pia Titterud & Rukke, Håkon Valen (2018). Antibacterial Activity of Endodontic Sealers against Planktonic Bacteria and Bacteria in Biofilms. Journal of Endodontics. ISSN 0099-2399. 44(1), p. 149–154. doi: 10.1016/j.joen.2017.08.023. Full text in Research Archive Show summary

  INTRODUCTION: The aim of this study was to investigate the antibacterial activity of 4 endodontic sealers against bacteria planktonic grown or in biofilms commonly detected from persistent and secondary endodontic infections. METHODS: The antibacterial activity of the sealers AH Plus, TotalFill BC sealer, RoekoSeal, and Guttaflow 2 was investigated for planktonic grown and 24-hour-old biofilms of Enterococcus faecalis, Staphylococcus epidermidis, Staphylococcus aureus, and Streptococcus mutans. RESULTS: AH Plus had high antibacterial activity toward all species investigated, both planktonic and in biofilms. However, the antibacterial activity was lost after 24 hours. TotalFill BC sealer showed marked antibacterial effect on planktonic bacteria up to 7 days after setting. TotalFill BC sealer had lower antibacterial activity against biofilms of S. aureus and E. faecalis compared with AH Plus when direct contact between the sealer and biofilm was investigated and for all species investigated when a membrane was used to separate the biofilm and sealer. Guttaflow 2 and RoekoSeal had no antibacterial activity against planktonic bacteria or bacteria in biofilms. CONCLUSIONS: Bacteria in biofilms showed higher susceptibility for AH Plus compared with TotalFill BC sealer during the first 24 hours after setting. Investigating the antibacterial activity of endodontic sealers and materials against bacteria in biofilms is highly important to evaluate the materials' ability to eradicate bacteria from the infected root canal.

• Jungnickel, Luise; Kruse, Casper; Vaeth, Michael & Kirkevang, Lise-Lotte (2018). Quality aspects of ex vivo root canal treatments done by undergraduate dental students using four different endodontic treatment systems. Acta Odontologica Scandinavica. ISSN 0001-6357. 76(3), p. 169–174. doi: 10.1080/00016357.2017.1396494. Full text in Research Archive
• Kapralos, Vasileios; Koutroulis, Andreas; Ørstavik, Dag; Sunde, Pia Titterud & Rukke, Håkon Valen (2018). Antibacterial Activity of Endodontic Sealers against Planktonic Bacteria and Bacteria in Biofilms. Journal of Endodontics. ISSN 0099-2399. doi: 10.1016/j.joen.2017.08.023. Full text in Research Archive
• Mikrogeorgis, Georgios; Irinakis, Eleni; Kapralos, Vasileios; Koutroulis, Andreas; Lyroudia, Kleoniki & Pitas, Ioannis (2018). Diagnosis of vertical root fractures in endodontically treated teeth utilising Digital Subtraction Radiography: A case series report. Australian Endodontic Journal. ISSN 1747-4477. Full text in Research Archive
• Bahrami, Golnosh; Væth, Michael; Kirkevang, Lise-Lotte; Wenzel, Ann & Isidor, Flemming (2017). The impact of smoking on marginal bone loss in a 10-year prospective longitudinal study. Community Dentistry and Oral Epidemiology. ISSN 0301-5661. 45(1), p. 59–65. doi: 10.1111/cdoe.12260. Full text in Research Archive
• Schropp, Lars & Kirkevang, Lise-Lotte (2017). Accurancy and Reliability of intraoral Radiographs in Determining the Cleanliness of Root Canals after Endodontic Retreatment. European Endodontic journal. ISSN 2548-0839. 2(2:20), p. 1–5. doi: 10.5152/eej.2017.17014. Full text in Research Archive
• Rodrigues, Renata Costa Val; Zandi, Homan; Kristoffersen, Anne Karin; Enersen, Morten; Mdala, Ibrahimu & Ørstavik, Dag [Show all 8 contributors for this article] (2017). Influence of the apical preparation size and the irrigant type on bacterial reduction in root canal - treated teeth with apical periodontitis. Journal of Endodontics. ISSN 0099-2399. 43(7), p. 1058–1063. doi: 10.1016/j.joen.2017.02.004. Full text in Research Archive
• Johnsen, Gaute Floer; Dara, Sazan; Asjad, Sameenah; Sunde, Pia Titterud & Haugen, Håvard Jostein (2017). Anatomic Comparison of Contralateral Premolars. Journal of Endodontics. ISSN 0099-2399. 43(6), p. 956–963. doi: 10.1016/j.joen.2017.01.012. Full text in Research Archive Show summary

  Introduction The comparative anatomy of contralateral premolars has not been previously studied. The purpose of this micro–computed tomography investigation was to qualitatively and quantitatively assess and compare the morphology of contralateral premolars in terms of length, canal width, dentinal thicknesses, accessory canals, root canal configurations, isthmi, C-shapes, root canal orifices, and apical foramina. The null hypothesis (H0) is that contralateral premolars are more morphologically similar than randomly assigned pairs for simple morphometric measurements (lengths, canal widths, and dentinal thickness). Methods Forty-one intact premolar pairs (n = 82) extracted from 28 patients were scanned with micro–computed tomography and reconstructed. Quantitative comparative assessment of measurements was performed by pairwise statistical analysis of contralateral and random pairs with Student t test and one-sample t test. All measured parameters (lengths, widths, and thicknesses) were normalized by Z score so that they could all be compared on a common scale. A correlation study was also performed. Canal configurations and isthmi were classified according to preexisting classification schemes. The number and location of accessory canals and apical foramina were registered and compared. Results/Conclusions Contralateral premolar pairs demonstrated a high degree of similarity in terms of the linear measurements (lengths, widths, and thicknesses). The apical portion (foramina, C-shapes, and accessory canals) did not demonstrate bilateral symmetry. The comprehensive statistical analysis of the normalized parameters by Z score showed no statistically significant differences between the contralateral premolar pairs. The null hypothesis (H0) was accepted.

• Johnsen, Gaute Floer; Rukke, Håkon Valen & Ørstavik, Dag (2016). Endodontiske materialer – skyllemidler, sealere og obturerende materialer. Tandlægebladet. ISSN 0039-9353. 120(12), p. 1080–1088. Full text in Research Archive Show summary

  Rodfyldningen afslutter den klassiske triade i endodontisk behandling: biomekanisk (kemomekanisk) instrumentering, desinfektion og obturation. Hensigten med rodfyldningen er at hindre penetration af bakterier ind til rodkanalen (rodkanalsystemet) og at hindre næringstilførsel og opvækst af tilbageværende bakterier. Rodfyldningens funktioner bliver således at udfylde og tætne kanalen og at dræbe eventuelle mikroorganismer. Dette opnås oftest ved brug af et kernemateriale og en sealer. Kernematerialet fungerer som et stempel, der både udfylder tomrummet og får sealeren til at udfylde rodkanalsystemet. Ud over tæt kontakt til dentin vil sealeren også være i kontakt med periapikalt blødtvæv. Dette medfører, at der stilles både materialetekniske og biologiske krav til sealeren. Rodfyldningen afsluttes med en koronal forsegling for at hindre indtrængen af bakterier koronalt fra. En tæt og fuldstændig rodfyldning bedømt røntgenologisk, med efterfølgende adækvat koronal restaurering, er en pålidelig prædiktor for et vellykket resultat. Artiklen omtaler instrumenteringsteknikker, indføring i de almindeligste skyllemidler samt egenskaber ved kernematerialer og sealere.

• Kruse, Casper; Spin-Neto, Rubens; Christiansen, Rene B.; Wenzel, Ann & Kirkevang, Lise-Lotte (2016). Periapical bone healing after apicectomy with and without retrograde root filling with mineral trioxide aggregate: A 6-year follow-up of a randomized controlled trial. Journal of Endodontics. ISSN 0099-2399. 42(4), p. 533–537. doi: 10.1016/j.joen.2016.01.011. Full text in Research Archive
• Jonasson, Peter; Kirkevang, Lise-Lotte; Rosén, Annika & Bjørndal, Lars (2016). Acute dental pain 2: pulpal and periapical pain :. Den norske tannlegeforenings Tidende. ISSN 0029-2303. 126(1), p. 20–26. Full text in Research Archive
• Zandi, Homan; Rodrigues, Renata C.V.; Kristoffersen, Anne Karin; Enersen, Morten; Mdala, Ibrahimu & Ørstavik, Dag [Show all 8 contributors for this article] (2016). Antibacterial Effectiveness of 2 Root Canal Irrigants in Root-filled Teeth with Infection: A Randomized Clinical Trial. Journal of Endodontics. ISSN 0099-2399. 42(9), p. 1307–1313. doi: 10.1016/j.joen.2016.06.006. Full text in Research Archive
• Dervenis, Konstantinos; Koutroulis, Andreas; Chatzopoulos, Georgios & Kapralos, Vasileios (2015). Technical Quality and Associated Iatrogenic Errors of Endodontic Treatments Performed in Extracted Anterior Single-Rooted Teeth by Preclinical Undergraduate Students. Balkan Journal of Dental Medicine. ISSN 2335-0245. Full text in Research Archive
• Kirkevang, Lise-Lotte; Ørstavik, Dag; Bahrami, G; Wenzel, A & Væth, Michael (2015). Prediction of periapical status and tooth extraction. International Endodontic Journal. ISSN 0143-2885. 50(1), p. 5–14. doi: 10.1111/iej.12581. Full text in Research Archive
• Prestegaard, Harald; Portenier, Isabelle; Ørstavik, Dag; Kayaoglu, G; Haapasalo, Marcus P & Endal, Unni (2014). Antibacterial activity of various root canal sealers and root-end filling materials in dentin blocks infected ex vivo with Enterococcus faecalis. Acta Odontologica Scandinavica. ISSN 0001-6357. p. 1–7. doi: 10.3109/00016357.2014.931462. Full text in Research Archive
• Jordal, Kristin; Valen, Anthony & Ørstavik, Dag (2014). Periapical status of root-filled teeth in Norwegian children and adolescents. Acta Odontologica Scandinavica. ISSN 0001-6357. doi: 10.3109/00016357.2014.913193. Full text in Research Archive
• Kruse, C; Spin-Neto, R; Wenzel, A & Kirkevang, Lise-Lotte (2014). Cone beam computed tomography and periapical lesions: A systematic review analysing studies on diagnostic efficacy by a hierarchical model. International Endodontic Journal. ISSN 0143-2885. 48(9), p. 815–828. doi: 10.1111/iej.12388. Full text in Research Archive
• Kirkevang, Lise-Lotte; Ørstavik, Dag; Wenzel, A & Vaeth, M (2014). Prognostic value of the full-scale Periapical index. International Endodontic Journal. ISSN 0143-2885. 48(11), p. 1051–1058. doi: 10.1111/iej.12402. Full text in Research Archive
• Kirkevang, Lise-Lotte; Væth, Michael & Wenzel, Ann (2014). Ten-year follow-up of root filled teeth: A radiographic study of a Danish population. International Endodontic Journal. ISSN 0143-2885. 47(10), p. 980–988. doi: 10.1111/iej.12245. Full text in Research Archive
• Sunde, Pia Titterud & Dahlén, Gunnar (2014). Aseptikk og antiseptikk i endodontien. Sunde PT, Dahlèn G. Tandlægebladet 2014; 7: 522-527. Tandlægebladet. ISSN 0039-9353. Full text in Research Archive
• Ajuz, Natasha C.C.; Armada, Luciana; Goncalves, Lucio S.; Debelian, Gilberto Jirair & Siqueira, Jose F. (2013). Glide Path Preparation in S-shaped Canals with Rotary Pathfinding Nickel-Titanium Instruments. Journal of Endodontics. ISSN 0099-2399. 39(4), p. 534–537. doi: 10.1016/j.joen.2012.12.025. Full text in Research Archive
• Lodiene, Greta; Kopperud, Hilde Beate M.; Ørstavik, Dag & Bruzell, Ellen (2013). Detection of leachables and cytotoxicity after exposure to methacrylate- and epoxy-based root canal sealers in vitro. European Journal of Oral Sciences. ISSN 0909-8836. 121, p. 488–496. doi: 10.1111/eos.12065. Full text in Research Archive Show summary

  Root canal sealing materials may have toxic potential in vitro depending on the cell line, cytotoxicity assay, material chemistry, and degree of polymer curing. The aims of the present study were to detect leaching components from epoxy- or methacrylate-based root canal sealers and to investigate the degree of cytotoxicity after exposure to extracts from these materials. Qualitative determination of substances released from the materials was performed by gas- and liquid chromatography/mass spectrometry. Submandibular salivary gland acinar cell death (apoptosis/necrosis) was determined using a fluorescence staining/microscopy technique. The major leachable monomer from the epoxy-based material was bisphenol-A diglycidyl ether (BADGE), whereas leachables from the methacrylate-based materials were mainly triethylene glycol dimethacrylate (TEGDMA), urethane dimethacrylate (UDMA), hydroxyethyl methacrylate (HEMA), and polyethyleneglycol dimethacrylate (PEGDMA). Exposure to diluted extracts of cured methacrylate-based materials caused a postexposure time-dependent increase in cell death. This effect was not demonstrated as a result of exposure to undiluted extract of cured epoxy-based material. Extracts of all fresh materials induced apoptosis significantly, but at lower dilutions of the epoxy- than the methacrylate-based materials. The degree of leaching, determined from the relative chromatogram peak heights of eluates from the methacrylate-based sealer materials, corresponded with the degree of cell death induced by extracts of these materials.

• Huumonen, Sisko & Ørstavik, Dag (2013). Radiographic follow-up of periapical status after endodontic treatment of teeth with and without apical periodontitis. Clinical Oral Investigations. ISSN 1432-6981. 17(9), p. 2099–2104. doi: 10.1007/s00784-013-0926-2. Full text in Research Archive Show summary

  Objectives. The aim was to assess objectively the rate of changes in periapical status after endodontic treatment in relation to preoperative radiographic status (Periapical Index Score, PAI) and to tooth type. Material and Methods. Radiographic data from a total of 1,410 teeth in seven prospective clinical studies was pooled. The periapical status was evaluated blindly using the PAI scoring system. The longest follow-up period was 4 years; intervals between controls varied from 3 months to 1 year. Results. Teeth with preoperative PAI score 1 maintained excellent periapical health throughout. Teeth with preoperative PAI score 2 showed some impairment in health over the first 6 months, but improved to approach 95 % healthy teeth at 2 years of observation. Teeth with PAI 3–5 at the start showed significant improvement at 3 months; 27 % were considered healthy (PAI 1 or 2) increasing to 41 % after 1 year. Improvement of periapical status was slower in PAI groups 4 and 5 compared with PAI 3 during the first year. After 2 years, improvement continued similarly in all preoperative PAI 3–5 groups of teeth. Upper lateral incisors showed the poorest healing rate. Conclusions. Healing of pre-existing periapical lesions is most pronounced from 3 months to 2 years. Teeth with initially healthy periapical structures predictably maintain good periapical health. Maxillary teeth, especially lateral incisors, showed poorer healing rates than mandibular teeth. Clinical relevance. Radiographic healing rates may vary among tooth groups within the dentition. Periapically healthy teeth that are root filled may not need postoperative controls.

• Moor, R. De; Hülsmann, M.; Kirkevang, Lise-Lotte; Tanalp, J. & Whitworth, J. (2013). European Society of Endodontology. Undergraduate Curriculum Guidelines for Endodontology. International Endodontic Journal. ISSN 0143-2885. 46, p. 1105–14. doi: 10.1111/iej.12186. Full text in Research Archive
• Møller, Line; Wenzel, Ann; Wegge-Larsen, Anne Mette; Ding, Ming; Væth, Michael & Hirsch, Edgar [Show all 7 contributors for this article] (2013). Comparison of images from digital intraoral receptors and cone beam computed tomography scanning for detection of voids in root canal fillings: an in vitro study using micro-computed tomography as validation. Oral surgery, oral medicine, oral pathology and oral radiology. ISSN 2212-4403. 115(6), p. 810–818. doi: 10.1016/j.oooo.2013.03.008. Full text in Research Archive
• Ørstavik, Dag (2011). Irrigasjonsmidler til endodontisk behandling - materialer og metoder. In Holmstrup, Palle (Eds.), AKTUEL NORDISK ODONTOLOGI 2011 36. ÅRGANG. Munsgaard Danmark. ISSN 9788762809963. p. 53–68. Full text in Research Archive
• Lodiene, Greta; Kleivmyr, Marianne; Bruzell, Ellen & Ørstavik, Dag (2011). Sealing ability of mineral trioxide aggregate, glass ionomer cement and composite resin when repairing large furcal perforations. British Dental Journal. ISSN 0007-0610. 210(5). doi: 10.1038/sj.bdj.2011.198. Full text in Research Archive
• Myrhaug, Thomas; Grytten, Jostein Ivar; Sandvik, Leiv & Ørstavik, Dag (2011). Kliniske rutiner ved rotbehandling hos spesialister i endodonti og allmennpraktiserende tannleger i Norge. Den norske tannlegeforenings Tidende. ISSN 0029-2303. 121(5), p. 300–304. Full text in Research Archive
• Endal, Unni; Shen, Ya; Årving, Knut; Gao, Yuan & Haapasalo, Markus (2011). A High-resolution Computed Tomographic Study of Changes in Root Canal Isthmus Area by Instrumentation and Root Filling. Journal of Endodontics. ISSN 0099-2399. 37(2), p. 223–227. doi: 10.1016/j.joen.2010.10.012. Full text in Research Archive
• Mutluay, Mustafa Murat; Oguz, Serra; Ørstavik, Dag; Fløystrand, Finn; Dogan, Arife & Soderling, Eva [Show all 8 contributors for this article] (2010). Experiments on in vivo biofilm formation and in vitro adhesion of Candida species on polysiloxane liners. Gerodontology. ISSN 0734-0664. 27(4), p. 283–291. doi: 10.1111/j.1741-2358.2009.00329.x. Full text in Research Archive
• Lopes, Helio P.; Elias, Carlos N.; Vieira, Victor T.L.; Moreira, E.S.; Marques, Raquel V.L. & Oliveira, JCM de [Show all 8 contributors for this article] (2010). Effects of Electropolishing Surface Treatment on the Cyclic Fatigue Resistance of BioRace Nickel-Titanium Rotary Instruments. Journal of Endodontics. ISSN 0099-2399. 36(10), p. 1653–1657. doi: 10.1016/j.joen.2010.06.026. Full text in Research Archive
• Dahl, Jon Einar & Ørstavik, Dag (2010). Responses of the pulp–dentin organ to dental restorative biomaterials. Endodontic Topics. ISSN 1601-1538. 17, p. 65–73. doi: 10.1111/j.1601-1546.2010.00250.x. Full text in Research Archive
• Mutluay, Mustafa Murat; Oguz, Serra; Ørstavik, Dag; Fløystrand, Finn; Dogan, Arife & Soderling, Eva [Show all 8 contributors for this article] (2010). Experiments on in vivo biofilm formation and in vitro adhesion of Candida species on polysiloxane liners. Gerodontology. ISSN 0734-0664. 27, p. 283–291. doi: 10.1111/j.1741-2358.2009.00329.x. Full text in Research Archive
• Ørstavik, Dag (2009). Thomas R. Pitt Ford: detail, diligence and determination. International Endodontic Journal. ISSN 0143-2885. 42, p. 382–385. doi: 10.1111/j.1365-2591.2008.01528.x. Full text in Research Archive
• Eldeniz, AU & Ørstavik, Dag (2009). A laboratory assessment of coronal bacterial leakage in root canals filled with new and conventional sealers. International Endodontic Journal. ISSN 0143-2885. 42(4), p. 303–312. doi: 10.1111/j.1365-2591.2008.01509.x. Full text in Research Archive
• Bindslev, Preben Hørsted & Ørstavik, Dag (2009). Endodontisk behandling med Mineral Trioxid Aggregat. In Holmstrup, Palle (Eds.), Aktuel nordisk odontologi 2010. 35. årgang. Munksgaard Forlag. ISSN 9788762809192. p. 127–140. Full text in Research Archive
• Ørstavik, Dag (2009). Diagnosis, Epidemiology, and Global Impact of Endodontic Infections. In Fouad, Ashraf F. (Eds.), Endodontic Microbiology. Wiley-Blackwell. ISSN 9780813826462. p. 12–21. Full text in Research Archive
• Endal, Unni (2009). Maskinell preparering av rotkanaler - er det forskjell på de forskjellige fabrikanter? In Holmstrup, Palle (Eds.), Aktuel nordisk odontologi 2010. 35. årgang. Munksgaard Forlag. ISSN 9788762809192. p. 113–126. Full text in Research Archive
• Bruseth, Ane Marthe; Sætervold, Heidi; Ørstavik, Dag & Preus, Hans Ragnar (2009). Overlevelse av endodontisk behandlede tenner med alvorlig periodontalt festetap. Den norske tannlegeforenings Tidende. ISSN 0029-2303. 119(15), p. 996–999. Full text in Research Archive
• Ordinola-Zapata, R; Bramante, CM; Bernardineli, N; Graeff, MSZ; Garcia, RB & Moraes, IG de [Show all 7 contributors for this article] (2009). A preliminary study of the percentage of sealer penetration in roots obturated with the Thermafil and RealSeal-1 obturation techniques in mesial root canals of mandibular molars. Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology, and Endodontics. ISSN 1079-2104. 108(6), p. 961–968. doi: 10.1016/j.tripleo.2009.07.016. Full text in Research Archive

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• Kirkevang, Lise-Lotte (2013). Ændringer i endodontisk status i Skandinavien gennem de sidste 40 år. Munksgaard Forlag, Danmark. ISBN 9788762811867. 256 p. Full text in Research Archive
• Ørstavik, Dag (2012). Healing of Chronic Apical Periodontitis, Chapter 16, Bok: Endodontic Radiology. Wiley-Blackwell. ISBN 9780470958490. 425 p. Full text in Research Archive
• Ørstavik, Dag (2010). Intracanal medication, Chapter 8, Bok:Harty`s Endodontics in Clinical Practice. Churchill Livingstone, Elsevier. ISBN 9780702031564. 293 p. Full text in Research Archive

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• Sødal, Anne Thea Tveit; Skudutyte-Rysstad, Rasa; Diep, My Tien & Hove, Lene Hystad (2026). Risk Indicators for Irregular Dental Attendance Among 65-Year-Olds in Oslo. Full text in Research Archive
• Torgersen, Gerald R.; Winsnes, Karianne Ervik; Handal, Trude & Sunde, Pia Titterud (2025). Visualizing AI Decisions in Automated Periapical Index Assessment. Full text in Research Archive Show summary

  Objective: Explainable artificial intelligence (XAI) is critical for clinical acceptance of AI models in dental radiology. This study explores the use of XAI—primarily Grad-CAM and LayerCAM—to interpret deep learning-based Periapical Index (PAI) scoring from intraoral radiographs, with a focus on exploring attentions patterns, meaning the areas contributing to the models decision of PAI score. Methods: We trained an open-source deep learning model for PAI classification on 300×300 pixel radiographic clips, using expert-labeled data. Grad-CAM and LayerCAM were applied to visualize model attention, generating class-specific average heatmaps and analyzing individual cases for anatomical plausibility and potential artifacts. Additional XAI methods were explored for comparison. Code and weights will be published together with the main publication. Results: XAI visualizations revealed that model attention patterns systematically varied with PAI class: lower scores showed focused periapical activation, while higher scores exhibited more diffuse and multi-focal attention. Individual heatmaps highlighted both expected anatomical focus and occasional peripheral activations, suggesting areas for further model refinement. LayerCAM and Grad-CAM provided complementary insights into model interpretability. Conclusions: Grad-CAM and related XAI methods offer valuable insights into the decision-making of AI models for PAI scoring. Ongoing work aims to refine XAI techniques and analyze individual attention maps to improve both model performance and interpretability.

• Torgersen, Gerald & Winsnes, Karianne Ervik (2024). Hot Insights: Explainable AI and Heatmaps for Accurate PAI-Scoring in Endodontic Treatments. Full text in Research Archive Show summary

  Introduction The application of Convolutional Neural Networks (CNN) for pathology detection within dental imaging is rapidly expanding(1). Evaluating the outcome of root canal treatments, particularly using the periapical index (PAI)(2), is crucial in endodontics. Traditionally, PAI scoring involves qualitative judgment following a calibration process. However, as Pythagoras famously noted, there is no such thing as quality in the world; everything is based on numbers. Previous studies have demonstrated the potential of CNNs in automating PAI scoring(3,4). Building on this work, our project, in collaboration with endodontic specialist residents, aims to develop a CNN model for accurate PAI scoring on dental radiographs. This year, our focus shifts to enhancing interpretability by visualizing regions of interest using a Gradient-weighted Class Activation Map (Grad-CAM) (5). By doing so, we aim to uncover the underlying quantitative factors that influence PAI classification. This method not only enhances model transparency but also aligns with the principles of explainable AI, providing valuable insights for clinical decision-making. Methods A set of 300 x 300 pixel clips, centered on the apex and scored by an experienced general dental practitioner working at the Department of endodontics, were used for transfer learning on an EfficientNet B3 model(6) pretrained on the ImageNet dataset(7). When inferencing test images we used the Grad-Cam framework to visualize impact of image areas on choosing different classes. Results The heatmaps show attention localized to the apex on the inferred class. Conclusion Heatmaps provide insight into the areas the model focuses on when determining the class. Further analysis will be conducted to utilize this information to enhance the machine learning approach for PAI scoring. We also plan to use the heatmaps as feedback to the human scorers. References 1. Pauwels R. A brief introduction to concepts and applications of artificial intelligence in dental imaging. Oral Radiol. 2021 Jan;37(1):153–60. 2. Ørstavik D, Kerekes K, Eriksen HM. The periapical index: A scoring system for radiographic assessment of apical periodontitis. Dent Traumatol. 1986 Feb;2(1):20–34. 3. Moidu NP, Sharma S, Chawla A, Kumar V, Logani A. Deep learning for categorization of endodontic lesion based on radiographic periapical index scoring system. Clin Oral Investig. 2022 Jan;26(1):651–8. 4. Pauwels R, Brasil DM, Yamasaki MC, Jacobs R, Bosmans H, Freitas DQ, et al. Artificial intelligence for detection of periapical lesions on intraoral radiographs: Comparison between convolutional neural networks and human observers. Oral Surg Oral Med Oral Pathol Oral Radiol. 2021 May;131(5):610–6. 5. Selvaraju RR, Cogswell M, Das A, Vedantam R, Parikh D, Batra D. Grad-CAM: Visual Explanations from Deep Networks via Gradient-Based Localization. Int J Comput Vis. 2019 Oct;128(2):336–59. 6. Tan M, Le QV. EfficientNet: Rethinking Model Scaling for Convolutional Neural Networks. 2019 [cited 2024 Aug 1]; Available from: https://arxiv.org/abs/1905.11946 7. Yang K, Qinami K, Fei-Fei L, Deng J, Russakovsky O. Towards Fairer Datasets: Filtering and Balancing the Distribution of the People Subtree in the ImageNet Hierarchy. In: Conference on Fairness, Accountability, and Transparency. 2020.

• Torgersen, Gerald R. & Winsnes, Karianne Ervik (2024). PAI meets AI – Can Artificial Intelligence Perform Classification of Endodontic Treatment Outcomes? Full text in Research Archive Show summary

  Aim: To identify the most effective convolutional neural network (CNN) model for fine-tuning on a dataset of intraoral radiographs and to evaluate the accuracy of the fine-tuned model in classifying the periapical index (PAI), thereby determining the model‘s capability in accurately reflecting endodontic treatment outcomes. Material and Methods: The model employed anonymized intraoral radiographs with landmarks and PAI scores from endodontic treatments performed at the University of Oslo. Scores were done by master students, residents in endodontics and PHD-candidates. A plugin to ImageJ was used to manually mark landmarks and set the PAI as an indicator for treatment outcome. The PyTorch library in the Python programming language was used to fine-tune and test several pretrained opensource CNN models. Several models including RESNET and VGG19 were fine-tuned on our dataset and tested for accuracy. Results: A fine-tuned VGG19 based model performed best, achieving an accuracy rate of 64%. Conclusion: While applying machine learning to image analysis in standard datasets, such as handwritten digits (MNIST) or flower classification, appears straightforward, the development of a model tailored to endodontic treatment evaluation poses significant challenges. Further results from refinement of training data and experimenting with different CNN models will be presented.

• Handal, Trude & Sunde, Pia Titterud (2023). Hvordan går det med rotfylte tenner? Full text in Research Archive
• Kapralos, Vasileios; Sunde, Pia Titterud; Camilleri, Josette; Morisbak, Else; Koutroulis, Andreas & Ørstavik, Dag Solmund [Show all 7 contributors for this article] (2022). Erratum: ‘Erratum to “Effect of chlorhexidine digluconate on antimicrobial activity, cell viability and physicochemical properties of three endodontic sealers” [Dent Mater 38 (2022) 1044–1059]’, (S0109564122001014), (10.1016/j.dental.2022.04.013). Dental Materials. ISSN 0109-5641. 38(7), p. 1232–1233. doi: 10.1016/j.dental.2022.05.004. Full text in Research Archive
• Handal, Trude (2022). Er du kalibrert? Full text in Research Archive
• Haugen, Håvard Jostein; Nogueira, Liebert Parreiras & Sunde, Pia Titterud (2021). Use of novel contrast enhanced agent for tissue engineering. Full text in Research Archive
• Handal, Trude & Sunde, Pia Titterud (2020). Rotresorpsjoner. Full text in Research Archive
• Liskiewicz, Krystyna Anna; Sunde, Pia Titterud; Verket, Anders; Økstad, Ole Andreas & Simm, Roger (2019). C-di-GMP signaling in Treponema denticola and its role in pathogenesis of periodontal diseases. Full text in Research Archive
• Liskiewicz, Krystyna Anna; Sunde, Pia Titterud; Verket, Anders; Økstad, Ole Andreas & Simm, Roger (2019). C-di-GMP signaling in Treponema denticola and its role in pathogenesis of periodontal diseases. Full text in Research Archive
• Jungnickel, Luise; Kruse, Casper; Hjortdal, Jesper Østergaard & Kirkevang, Lise-Lotte (2018). Visuelle hjælpemidler under endodontisk behandling. Tandlægebladet. ISSN 0039-9353. 122(1), p. 900–904. Full text in Research Archive
• Herlofson, Bente Brokstad; Preus, Hans Ragnar; Rønold, Hans Jacob; Ørstavik, Dag & Reppen, Kjetil (2017). Hvorfor gikk det galt? Full text in Research Archive
• Johnsen, Gaute Floer; Rukke, Håkon Valen & Ørstavik, Dag (2017). Endodontiske materialer - skyllemidler, sealere og obturerende materialer. Den norske tannlegeforenings Tidende. ISSN 0029-2303. 127(3), p. 248–256. Full text in Research Archive
• Sunde, Pia Titterud (2017). Akuttbehandling, systemiske komplikasjoner Klinisk og røntgenologisk diagnostikk Kliniske rutiner, hvordan gjør vi det nå? Full text in Research Archive
• Ørstavik, Dag (2017). Obturation of Root Canals. In Chugal, N & Lin, LM (Ed.), Endodontic Prognosis. Springer Publishing Company. ISSN 9783319424125. p. 141–159. Full text in Research Archive
• Duncan, H.F.; Kirkevang, Lise-Lotte; Ørstavik, Dag & Sequeira-Byron, P. (2016). Research that matters - clinical studies. International Endodontic Journal. ISSN 0143-2885. 49(3), p. 224–226. doi: 10.1111/iej.12590. Full text in Research Archive
• Jonasson, Peter; Kirkevang, Lise-Lotte; Rosén, Annika & Bjørndal, Lars (2016). Akut tandvärk II: Pulpasmärta och periapikal smärta. Tandläkartidningen. ISSN 0039-6982. p. 64–71. Full text in Research Archive
• Kruse, C; Spin-Neto, R; Wenzel, A & Kirkevang, Lise-Lotte (2014). Cone beam computer-tomogafi (CBCT) til diagnostik af periapikale læsioner. Tandlægebladet. ISSN 0039-9353. 6, p. 448–59. Full text in Research Archive
• Kirkevang, Lise-Lotte; Kruse, C & Wæth, M (2014). Udviklingen i endodontisk status i en dansk population fulgt fra 1997 til 2008. Tandlægebladet. ISSN 0039-9353. 7, p. 560–567. Full text in Research Archive
• Zandi, Homan; Rodrigues, Renata C. V.; Kristoffersen, Anne Karin; Ørstavik, Dag; Siqueira, Jose F. & Rocas, Isabela [Show all 7 contributors for this article] (2014). Clinical effectiveness of two antimicrobial irrigants in endodontically treated teeth. Poster presentation. Full text in Research Archive
• Zandi, Homan; Rodrigues, Renata C. V.; Kristoffersen, Anne Karin; Ørstavik, Dag; Siqueira, Jose F. & Rocas, Isabela [Show all 7 contributors for this article] (2014). Clinical effectiveness of two antimicrobial irrigants in endodontically treated teeth. Oral presentation. Full text in Research Archive Show summary

  Clinical Effectiveness of Two Antimicrobial Irrigants in Endodontically Treated Teeth Homan Zandi, DDS, Renata C. V. Rodrigues, DDS, Anne-Karin Kristoffersen, PhD, Dag Ørstavik, DDS, PhD, José F. Siqueira Jr, DDS, PhD, Isabela Rôças, DDS, PhD, Morten Enersen, DDS, PhD Abstract Background: Endodontic treatment of root-filled teeth with post-treatment disease is especially challenging. The outcome of endodontic treatment is significantly influenced by the presence of bacteria in the root canals at the time of filling. Sodium hypochlorite (NaOCl) is widely used as a root canal irrigant in different concentrations because of its pronounced antimicrobial activity and the ability of dissolving necrotic tissue and organic matter. Chlorhexidine gluconate (CHX) is an effective substitute for NaOCl due to its broad-spectrum antimicrobial efficacy against bacteria and its high dentin substantivity. It is less toxic against vital tissues than NaOCl but lacks tissue dissolving property. No culture-independent molecular study has compared the antimicrobial effectiveness of 1% NaOCl and 2% CHX in root-filled teeth with apical periodontitis (AP). Objectives: The aim of the present study was to compare the antibacterial properties of 1% NaOCl and 2% CHX in endodontically treated teeth with AP. Methods: Sixty-eight root-filled teeth with AP were randomly distributed in two irrigant groups. Bacterial samples were taken at baseline (S1), after chemomechanical preparation using either 1% NaOCl or 2% CHX as irrigant (S2), and after intracanal medication with calcium hydroxide at the second visit (S3). The bacterial samples were analyzed by 16S rRNA gene-based quantitative polymerase chain reaction (qPCR) for total bacteria, Enterococcus faecalis and Streptococcus spp.. Results: Preliminary results indicated bacterial DNA in all the samples at S1. E. faecalis was seldom found, but streptococci were frequent. The amount of bacterial DNA significantly declined following treatment in both groups (S2 and S3) (p<0.001). There was no significant difference between NaOCl and CHX groups in reducing total bacterial and streptococcal counts (p>0.05). Conclusion: Findings indicate that endodontic retreatment was equally effective in reducing the amount of bacteria in both irrigation groups. Keywords: Endodontics. Root canal irrigants.

• Larsen, T; Ciofu, O; Moesby, L; Kirkevang, Lise-Lotte & Poulsen, AH (2013). Anvendelse af antibiotika i tandlægepraksis. Tandlægebladet. ISSN 0039-9353. 117, p. 386–397. Full text in Research Archive

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