Publications
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Hol, Caroline; Eliassen, Morten; Hjortsjö, Carl; Larheim, Tore Arne; Ninkov, Peter & Arvidsson, Linda Zamoline
(2026).
Osteoarthritis Development After Surgical Treatment of Disc Displacement in the Temporomandibular Joints. A Systematic Review.
Journal of Oral Rehabilitation.
ISSN 0305-182X.
2026,
p. 1–15.
doi:
10.1111/joor.70302.
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Background
Temporomandibular joint (TMJ) discectomy and disc repositioning surgery (DRS) remain treatment options for disc displacement (DD) when conservative and minimally invasive treatments fail. DRS and discectomy with disc replacement are used, in part, to prevent osteoarthritis (OA) development.
Objective
To assess evidence for OA development after surgical treatment of TMJ DD by comparing OA development in surgically treated TMJs to OA development in conservatively treated patients with DD.
Methods
A systematic search (Medline, Embase and Cochrane up to 3 October 2024) was performed, and PRISMA was followed. A lack of effect sizes precluded meta-analysis; a descriptive statistical comparison between groups was made (Student's t-test, χ2 test, significance level p < 0.05).
Results
Eight observational studies, including discectomy of 117 TMJs (DD with/without reduction; without replacement), 206 comparison TMJs (DDwoR; observation) and one DRS study, met the eligibility criteria. An additional case report met the eligibility criteria but was not included in data synthesis. Heterogeneity in study designs, diagnostic methods and criteria, and mostly high Risk of Bias according to GRADE was found. OA and OA-related findings increased in all discectomy and comparison studies at follow-up.
Conclusion
A consistent trend of increasing TMJ OA frequency was observed across the included studies in both operated and unoperated TMJs with DD. Most studies provided evidence of very low certainty. This systematic review could therefore not reliably evaluate whether TMJ discectomy is itself responsible for OA development. Further research is needed to determine the influence of surgical treatments of TMJ DD on OA.
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Khan, Sadia Nazir; Koldsland, Odd Carsten; Tiainen, Hanna & Hjortsjö, Carl
(2024).
Anatomical three-dimensional model with peri-implant defect for in vitro assessment of dental implant decontamination.
Clinical and Experimental Dental Research.
10(1).
doi:
10.1002/cre2.841.
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Abstract Objectives Access to the implant surface plays a significant role in effective mechanical biofilm removal in peri‐implantitis treatment. Mechanical decontamination may also alter the surface topography of the implant, potentially increasing susceptibility to bacterial recolonization. This in vitro study aimed to evaluate a newly developed, anatomically realistic, and adaptable three‐dimensional (3D)printed model with a peri‐implant bone defect to evaluate the accessibility and changes of dental implant surfaces after mechanical decontamination treatment. Material and Methods A split model of an advanced peri‐implant bone defect was prepared using 3D printing. The function of the model was tested by mechanical decontamination of the exposed surface of dental implants (Standard Implant Straumann AG) coated with a thin layer of colored occlusion spray. Two different instruments for mechanical decontamination were used. Following decontamination, the implants were removed from the split model and photographed. Image analysis and fluorescence spectroscopy were used to quantify the remaining occlusion spray both in terms of area and total amount, while scanning electron microscopy and optical profilometry were used to analyze alteration in the implant surface morphology. Results The 3D model allowed easy placement and removal of the dental implants without disturbing the implant surfaces. Qualitative and quantitative assessment of removal of the occlusion spray revealed differences in the mechanism of action and access to the implant surface between tested instruments. The model permitted surface topography analysis following the decontamination procedure. Conclusion The developed 3D model allowed a realistic simulation of decontamination of implant surfaces with colored occlusion spray in an advanced peri‐implant defect. 3D printing allows easy adaptation of the model in terms of the shape and location of the defect. The model presents a valuable tool for in vitro investigation of the accessibility and changes of the implant surface after mechanical and chemical decontamination.
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Khan, Sadia Nazir; Koldsland, Odd Carsten; Roos-Jansåker, Ann-Marie; Wohlfahrt, Johan Caspar; Verket, Anders & Mdala, Ibrahimu
[Show all 9 contributors for this article]
(2023).
Non-surgical treatment of mild to moderate peri-implantitis with an oscillating chitosan brush or a titanium curette—12-month follow-up of a multicenter randomized clinical trial.
Clinical Oral Implants Research.
ISSN 0905-7161.
doi:
10.1111/clr.14078.
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Khan, Sadia Nazir; Koldsland, Odd Carsten; Roos-Jansåker, Ann-Marie; Wohlfahrt, Johan Caspar; Verket, Anders & Mdala, Ibrahimu
[Show all 9 contributors for this article]
(2022).
Non-surgical treatment of mild to moderate peri-implantitis using an oscillating chitosan brush or a titanium curette—A randomized multicentre controlled clinical trial.
Clinical Oral Implants Research.
ISSN 0905-7161.
doi:
10.1111/clr.14007.
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Objectives This prospective, parallel-group, examiner-blinded, multicentre, randomized, controlled clinical trial aimed to assess the efficacy of an oscillating chitosan brush (OCB) versus titanium curettes (TC) on clinical parameters in the non-surgical treatment of peri-implantitis. Material and Methods In five dental specialist clinics, 39 patients with one implant with mild to moderate peri-implantitis, defined as 2–4 mm radiographic reduced bone level, bleeding index (BI) ≥ 2, and probing pocket depth (PPD) ≥ 4 mm were randomly allocated to test and control groups, receiving OCB or TC debridement, respectively. Treatment was performed at baseline and three months. PPD, BI, and Plaque index (PI) were measured at six sites per implant and recorded by five blinded examiners at baseline, one, three, and six month(s). Pus was recorded as present/not present. Changes in PPD and BI were compared between groups and analysed using multilevel partial ordinal and linear regression. Results Thirty-eight patients completed the study. Both groups showed significant reductions in PPD and BI at six months compared with baseline (p < .05). There was no statistically significant difference in PPD and BI changes between the groups. Eradication of peri-implant disease as defined was observed in 9.5% of cases in the OCB group and 5.9% in the TC group. Conclusions Within the limitations of this six-month multicentre clinical trial, non-surgical treatment of peri-implantitis with OCB and TC showed no difference between the interventions. Eradication of disease was not predictable for any of the groups.
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Mo, Arild; Hjortsjö, Carl & Jokstad, Asbjørn
(2022).
Maxillary overdenture on three implants retained by low-profile stud attachments – A prospective cohort study.
Journal of Oral Rehabilitation.
ISSN 0305-182X.
49(11),
p. 1069–1079.
doi:
10.1111/joor.13364.
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Background: Clinical data are needed on long-term outcomes of removable implantsupported prostheses in the fully edentulous maxilla as a function of the number of implants, effects of the attachment system and other clinical variables.<p> <p>Objective: To restore individuals with an edentate maxilla with a metal-reinforced removable prosthesis without palatal coverage retained by low-profile stud attachments on three implants. <p>Methods: The regional ethics committee approved a prospective cohort study that included all consecutive patients treated in a private speciality clinic. Primary outcomes were patients reported, that is denture satisfaction scale and oral health-related quality of life – OHIP-20. Secondary outcomes were implant- (bone loss, implant complications and peri-implant conditions) and prosthesis-related (prosthesis complications, maintenance needs and mucosa condition). <p>Results: Thirty-two study participants were recruited between March 2007 and October 2016 and followed for a minimum of five years. According to Kruskal–Wallis tests, the OHIP-20 and Denture Satisfaction Scale questionnaire pre-treatment scores differed significantly. After an average of 6.7 years, peri-implant bone loss of more than 2 mm was observed on 17% of all implants, while no or minor bone loss was seen on 38%. The estimated success of implants was 0.95 at 168 months. The estimated success of the prosthesis, that is no adverse events or need for any repairs, was 0.55 at 156 months. <p>Conclusion: The positive findings in the current clinical study strengthen the notion that for many individuals with an edentulous maxilla, a removable prosthesis retained by three implants fitted with low-profile stud-attachment is a reliable technical solution.
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Young, Alix; Hove, Lene Hystad; Stevning, Karen; Løvik, Sara-Emilie & Hjortsjö, Carl
(2021).
Kan tannpasta
gjøre tennene mer
sårbare?
En in vitro pilotstudie om endring
i fukting av emalje uttrykt ved
kontaktvinkelmålinger.
Den norske tannlegeforenings Tidende.
ISSN 0029-2303.
131(9),
p. 796–801.
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Brennhovd, Anders; Petrovski, Beata & Hjortsjö, Carl
(2020).
Benoppbygging
før implantatinnsetting – overlevelse og suksess.
Den norske tannlegeforenings Tidende.
ISSN 0029-2303.
130(10),
p. 796–805.
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Seitz, Elke; Hjortsjö, Carl; Dahl, Jon Einar & Saxegaard, Erik
(2020).
Dentin to dentin adhesion using combinations of resin cements and adhesives from different manufacturers - a novel approach.
Biomaterial Investigations in Dentistry.
7(1),
p. 96–104.
doi:
10.1080/26415275.2020.1793677.
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Aims The aims of this study were to present a novel method to analyse dentin bond strength and to evaluate the bond strength of combining adhesive systems and resin cement from different manufacturers. Methods Human wisdom teeth were ground flat to the dentin on parallel surfaces and axially cut into two parts. Dentin cylinders (Ø 3 mm) were drilled from one half of each tooth. The other half from each tooth was embedded in epoxy resin with the dentin surface exposed. The specimens were ground with silicone carbide paper and the dentin cylinders were cemented onto the dentin surface of the other half of the same tooth. Materials: Resin cement and adhesive systems from three different manufacturers were used in various combinations (n = 8 per group). Cement and adhesive from the same manufacturer served as control. Shear bond strength (SBS) was measured and fracture modes were registered. Results and conclusions: The highest median SBS value was found in a bonding combination between cement and a non-corresponding adhesive (33.1 MPa) and one of the lowest values was found in one of the controls (15.3 MPa). Cohesive fractures were most frequent. The results indicated that combining adhesive and cement from different manufacturers did not compromise the dentin bonding. The novel test method is recommended for evaluating dentin bonding.
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Ohrvik, Hanne Gran & Hjortsjö, Carl
(2019).
Retrospective study of patients with amelogenesis imperfecta treated with different bonded restoration techniques.
Clinical and Experimental Dental Research.
doi:
10.1002/cre2.243.
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Objective The aim of this retrospective study was to evaluate clinical success and satisfaction of patients with amelogenesis imperfecta treated with three different types of bonded restorations at a university clinic. Materials and Methods One hundred fifty‐four restorations in 15 subjects with mean age of 17.3 years (SD 8.2) were evaluated after treatment with three different types of bonded restorations: all ceramic enamel‐dentin bonded restorations, prefabricated composite veneers, and direct composite resin restorations. A modified version of the Californian Dental Association system for quality evaluation of dental care and a questionnaire assessing patient satisfaction were used for classification. The restorations were evaluated with respect to patient satisfaction, esthetics, technical, and biological complications. Results Mean observation period for the restorations was 42.5 months (SD 35.6). All restorations were in place at the time of the examination. Surface and color calibration showed a success of 95% for the ceramic enamel‐dentin bonded restorations, 44% for the direct composite resin restorations, and 0% for the prefabricated composite veneers. The same pattern was evident for anatomy and marginal integrity. The subjects reported a high degree of satisfaction with both the esthetics and function of their restorations. Conclusion The results indicated that all ceramic restorations demonstrated the best results for patients with amelogenesis imperfecta.
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Eliassen, Morten; Hjortsjö, Carl; Olsen-Bergem, Heming & Bjørnland, Tore
(2019).
Self-exercise programmes and occlusal splints in the treatment of TMD-related myalgia – Evidence-based medicine?
Journal of Oral Rehabilitation.
ISSN 0305-182X.
p. 1–7.
doi:
10.1111/joor.12856.
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Background The low‐cost and reversible treatments concerning disorders of the masticatory muscles represent a vast array of regimens. Common treatments include information, stretching exercises, manual therapy, acrylic splints and cognitive behavioural therapy. Objective The aim of this study was to evaluate the evidence behind the use of self‐exercising programmes and occlusal splints in the treatment of myofascial pain. Methods We conducted a thorough search of five databases, using four cardinal search terms in combination with twelve supporting terms. We also assessed the evidence quality, using GRADEpro software. Results The search resulted in 4967 individual studies. 18 studies met the inclusion criteria and were re‐evaluated. Conclusion The selected studies were in favour of a self‐care or an occlusal splint treatment of myalgia. However, a GRADE assessment showed that 14 of the 18 selected studies had low or very low evidence quality. Studies also showed weaknesses with regard to nomenclature and reproducibility. Hence, it is our professional opinion that the evidence level for prescribing self‐exercises and occlusal splints in the treatment of myalgia is low.
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Berntsen, Christian Skoe; Kleven, Martin; Heian, Marianne & Hjortsjø, Carl
(2018).
Clinical comparison of conventional and additive
manufactured stabilization splints.
Acta Biomaterialia Odontologica Scandinavica.
4(1),
p. 81–89.
doi:
10.1080/23337931.2018.1497491.
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The aim of this study was to compare conventional and digital additive manufacturing of hard occlusal stabilization splints (SS) using technical and clinical parameters. 14 subjects were subjected to DC/TMD Axis I clinical examination protocol and Axis II questionnaire. The subjects underwent treatment with splints over a period of 12 weeks. All subjects underwent both conventional alginate impression and intraoral digital scanning. Seven subjects received conventional manufactured stabilization splints (CM-SS), and seven subjects received CAD-CAM additive manufactured stabilization splints (AM-SS). 12 subjects completed the 12 weeks follow-up period. The subjects significantly preferred digital intraoral scanning compared to conventional alginate impression. There was a significant difference in VAS between CM-SS and AM-SS. The mean VAS result was 15 for AM-SS and 42 for CM-SS, 0 represented excellent comfort and 100 very uncomfortable. This was significant. Splint manufacturing method had no influence on treatment outcome. There was no significant difference in mean delta change for unassisted jaw opening from baseline to 12 weeks between the two groups, for CM-SS it was 2 mm difference and for AM-SS the difference was 3 mm. All subjects in both treatment groups showed improved oral function. In this study, the scanning procedure is more accepted by the subjects than alginate impressions, however the first procedure was more time consuming.
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Printzell, Lisa; Haseid, Carl Fredrik; Ekfeldt, Anders & Hjortsjø, Carl
(2016).
Clinical performance of enamel-dentine bonded all-ceramic restorations: retrospective evaluation in a postgraduate clinic.
Swedish Dental Journal.
ISSN 0347-9994.
40,
p. 203–212.
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Mo, Arild; Hjortsjø, Carl; Olsen-Bergem, Heming & Jokstad, Asbjørn
(2016).
Maxillary 3-implant removable prostheses without palatal coverage on Locator abutments – a case series.
Clinical Oral Implants Research.
ISSN 0905-7161.
27(10),
p. 1193–1199.
doi:
10.1111/clr.12724.
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Hjortsjø, Carl; Young, Alix; Kiesow, Andreas; Cismak, Andreas; Berthold, Lutz & Petzold, Matthias
(2015).
A Descriptive in vitro Electron Microscopic Study of Acidic Fluoride-Treated Enamel: Potential Anti-Erosion Effects.
Caries Research.
ISSN 0008-6568.
49(6),
p. 618–625.
doi:
10.1159/000441195.
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Hjortsjø, Carl; Mjølnerød, Jol Anders; Skaare, Anders; Jonski, Grazyna; Young, Alix & Ekfeldt, Anders
(2012).
A replica technique for studying the effect of fluoride solutions on enamel erosion.
Swedish Dental Journal.
ISSN 0347-9994.
36 ,
p. 169–178.
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Hjortsjø, Carl; Jonski, Grazyna; Young, Alix & Saxegaard, Erik
(2010).
Effect of acidic fluoride treatments on early enamel erosion lesions-A comparison of calcium and profilometric analyses.
Archives of Oral Biology.
ISSN 0003-9969.
55(3),
p. 229–234.
doi:
10.1016/j.archoralbio.2010.01.003.
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Objective: The protective effect of fluoride solutions against acidic challenge on enamel was tested in vitro using calcium- and profilometer analyses. Methods: HF-, SnF2-, TiF4- and NaF solutions (0.1M F-) and H2O as negative control were tested on a total of 60 enamel specimens divided into ten groups. Prior to and after F-treatment five groups were exposed for 1min to 0.01M citric acid, and the other five groups for 10min to 0.1M citric acid. Enamel specimens were measured by profilometry at baseline and before and after each acidic challenge. [Ca] in the collected citric acid samples was measured by atom absorption spectroscopy (AAS). ΔCa and Δ surface height were calculated for each specimen and the data were analysed using one way ANOVA, Tukeys test and Pearson r correlation. Results: AAS showed that F-treatments reduced enamel dissolution for both the 1min and 10min acidic challenge. Profilometry showed no significant differences between the F-solutions for the 1min groups. Significant differences could be seen between the fluorides for the 10min groups and there was a large correlation between the profilometric and AAS results. In conclusion, all fluoride solutions reduced enamel dissolution when specimens were exposed to a typical dietary acid. Conclusions: The profilometer was not sensitive enough to measure the effects of the different fluorides against a low acidic challenge as represented by this in vitro experiment. AAS was able to show these differences and for the 10 min acidic challenge there was a good correlation between the results from the two methods.
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Hjortsjø, Carl; Saxegaard, Erik; Young, Alix & Dahl, Jon Einar
(2009).
In vivo and in vitro irritation testing of low concentrations of hydrofluoric acid.
Acta Odontologica Scandinavica.
ISSN 0001-6357.
67(6),
p. 360–365.
doi:
10.1080/00016350903117118.
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Objective. Acidic fluorides are proposed for the treatment of dental erosion. The aim of this study was to examine the irritation properties of dilute hydrofluoric acid (HF) solutions for potential use in the oral cavity. Material and Methods. Hen’s Egg Test - chorioallantoic membrane (HET-CAM): The CAM was accessed by careful dissection through the egg shell (n=36, 6 eggs/test solution) and exposed to 300 µL of the HF solutions (0.05, 0.10, 0.20 and 1.0%) under macroscope examination over 5 min. Mean time-to-coagulation and average irritation score were recorded based on appearance of hemorrhage, coagulation and lysis of the blood vessels in the membrane. Mouse skin test: Sixty male mice were randomly divided into 10 groups of 6 animals (control, 0.05, 0.10, 0.20 and 1.0% HF), shaved on the back, exposed to test solution and sacrificed after 2h or 24h. Skin samples were evaluated by light microscopy, scoring epithelial leukocyte infiltration, vascular congestion, and edema. Results. HET-CAM: 0.05% HF was slightly irritant, 0.1% HF moderately irritant, 0.2% and 1% HF were strongly irritant. 0.1-1% HF solutions were severely eye irritating. Mouse skin test: HF concentration was significantly correlated with tissue response and 24-h exposure to 1% HF-solution showed focal erosion of the epithelium and marked localized subepithelial leukocyte infiltration. Conclusion. The results of these studies suggest that accidental exposure of soft tissues to solutions containing more than 0.2% HF may be harmful.
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Hjortsjø, Carl; Jonski, Grazyna; Thrane, Per Stanley; Saxegaard, Erik & Young, Alix
(2009).
Effect of Stannous Fluoride and Dilute Hydrofluoric Acid on Early Enamel Erosion over Time in vivo.
Caries Research.
ISSN 0008-6568.
43(6),
p. 449–454.
doi:
10.1159/000261415.
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Hjortsjø, Carl; Jonski, Grazyna; Thrane, Per Stanley; Saxegaard, Erik & Young, Alix
(2009).
The Effects of Acidic Fluoride Solutions on Early Enamel Erosion in vivo.
Caries Research.
ISSN 0008-6568.
43(2),
p. 126–131.
doi:
10.1159/000209345.
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Jokstad, Asbjørn; Meric, Gøkce & Hjortsjø, Carl
(2005).
A systematic review of the scientific documenttation of fixed partial dentures made form fiber-reinforced polymer to replace missing teeth.
International Journal of Prosthodontics.
ISSN 0893-2174.
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Khan, Sadia Nazir; Koldsland, Odd Carsten & Hjortsjö, Carl
(2019).
Bacteriostatic effect of filling materials used in implant-abutment-screw-channel: A pilot study.
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Hove, Lene Hystad; Young, Alix; Hjortsjø, Carl; Stevning, Karen & Løvik, Sara Emilie
(2017).
Effect of Whitening Toothpastes on Dental Enamel
In Vitro.
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Printzell, Lisa; Haseid, Carl Fredrik; Hjortsjø, Carl & Ekfeldt, Anders
(2016).
Kliniskt utfall av adhesivt cementerade helkeramiska restaureringar utförda på en specialistutbildningsklinik.
Den norske tannlegeforenings Tidende.
ISSN 0029-2303.
126(11),
p. 882–888.
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Hjortsjø, Carl; Jonski, Grazyna & Young, Alix
(2015).
Effect of Mouth-rinsing with Two Fluoride Solutions on Enamel Solubility Using an in vivo Experimental Model.
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Hjortsjø, Carl; Young, Alix; Kiesow, Andreas; Cismak, Andreas; Berthold, Lutz & Petzold, Matthias
(2013).
An electron microscopic study comparing effects of human enamel exposure to SnF2-, TiF4- and NaF-solutions.
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Hjortsjø, Carl; Jonski, Grazyna & Young, Alix
(2013).
A modified in vivo experimental model for evaluating fluoride treatment against initial erosion lesions.
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Hjortsjø, Carl; Jonski, Grazyna; Young, Alix & Saxegaard, Erik
(2011).
Erosive effect of acidic fluoride solutions on enamel in vitro.
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Acidic fluoride solutions have been shown to exhibit erosion-inhibiting properties on dental enamel. The aim of this in vitro study was to investigate the possible erosive effect of dilute hydrofluoric acid (HF) on enamel. A 0.2% HF solution (0.1 mol/l F-, pH 3.02) was compared with two acidic fluorides containing 0.5 mol/l F- (3.9% SnF2-pH 2.65 and 1.6% TiF4-pH 1.42) and 1.8% citric acid (acidic control, pH 2.27). 24 human third molar enamel specimens were randomly divided into 4 groups (6 specimen/solution). Enamel surfaces were ground flat by wet grinding with a grit 2500 abrasive paper and half of each flat surface was isolated using a A-silicon impression material. The enamel surfaces were exposed to 20ml of the test solutions for ten minutes in plastic containers. The isolation material was removed. and changes in the enamel surfaces were analysed by LED blue light profilometry (λ=470 nm, 50x magnification). The specimen area analysed included both treated and untreated ground enamel, a total area of 254.64 x 190.90 µm2 for each sample. The difference in surface height between treated and untreated enamel was calculated for each specimen and etching depth data were analysed using oneway ANOVA and Tukeys test. The mean etching depths (µm±SD) were 0.14(0.86), -2.00(0.52), -3.25(2.91) and 5.42(1.00) for, HF, SnF2, TiF4 and control respectively. HF had significantly less etching effect than the control, but was significantly more erosive than TiF4 (p<0.05). In conclusion, while both SnF2 and TiF4 treatments resulted in an average deposition on the enamel surface, HF showed an average etching effect close to zero. Further studies are needed to examine the mechanism of the previously described anti-erosive effect of HF.
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Young, Alix; Hjortsjø, Carl; Berthold, Lutz; Cismak, Andreas & Petzold, Matthias
(2011).
An electron microscopic study of enamel treated with hydrofluoric acid.
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Previous studies have demonstrated the effectiveness of treating enamel with acidic fluorides as a means of reducing the effects of erosive challenges. The aim of the present in vitro study was to investigate the surface characteristics of dental enamel treated with hydrofluoric acid (HF). Natural surfaces of enamel specimens from extracted human third molars were treated for 10 min with either native solutions of HF (pH 3) or sodium fluoride (NaF, pH 7) containing both 0.1 and 0.2 mol/l F-. Untreated samples functioned as controls. All specimens were examined by SEM/EDX with respect to surface microstructure variation and fluoridation. For selected specimens, samples were prepared by FIB allowing cross-sectional investigations using TEM and nanospot-EDX. Following treatment with HF, SEM/EDX analyses did not show obvious erosive damage but clearly indicated surface fluoridation. Using TEM, an enamel surface microstructure modification to a depth of approximately 200 nm with a clear boundary to non-affected apatite was revealed. The fluoride content in this layer was above 40at% F with a F/Ca ratio of roughly 2 indicating the transformation of surface hydroxyapatite into CaF2-like material. In previous studies, isolated fluoride-rich globular precipitates were found if medium-acidulated solutions of NaF were applied. The atomic composition of the HF-induced CaF2-like material resembled that of these precipitates. In contrast, no fluoridation effects were found for the NaF at pH 7 and the controls in this study. These results suggest that the general reaction between fluoride solutions and enamel leading to a formation of CaF2-like material does not significantly depend on the dissociated fluoride cation. On the other hand, the reaction rate for the acidic HF treatments is higher since the amount of dissolved calcium increases with decreasing pH.
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Hjortsjø, Carl; Jonski, Grazyna; Saxegaard, Erik & Young, Alix
(2009).
Profilometric study of the effects of acidic fluoride solutions on early dental erosion.
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An in-vivo experimental model for dental erosion has been utilised to assess the effects of treating dental enamel with fluorides. This in-vitro study aimed to examine the effects of the same acidic fluoride solutions using profilometry. Crowns of intact, surgically extracted human third molar teeth were cut into 2-4 pieces, washed (deionised water, 50% ethanol then 96% ethanol), embedded in acrylic resin and polished (grit 4000). Nail varnish was applied in a line across the block separating the enamel surface from the acrylic resin surface. Specimens were exposed to 5 ml of 100 mmol/L citric acid for 10 min before (etch I) and after (etch II) fluoride treatments. Aqueous solutions of TiF4, SnF2, HF or NaF, (all 0.1 M F-) and deionised water (negative control) were tested (n=6 specimens/test solution). All solutions were applied in a cell culture well (Nunclon, Nunc, Roskilde, Denmark) and enamel specimens were exposed to all the fluids in these wells. Specimens were analysed at all stages in a high power LED blue light profilometer (PLµ2300 Optical Imaging Profiler, Sensofar Tech, Spain) at 150x magnification and λ=470 nm. Areas including one half of exposed enamel and the other half varnish-covered enamel (220.98 x 165.68µm) were analysed to a depth of 40µm. Data analysis compared the step-height differences between the exposed and the varnished reference areas. Paired t-test and Kruskal-Wallis ANOVA on Ranks were used in the statistical analysis. There was a significant reduction in step height difference following HF-, SnF2-, and TiF4-treatments (p ≤0.005), but not for the NaF and water. The acidic fluoride solutions were capable of reducing the erosive effect of the citric acid challenge as previously shown in the in vivo experimental model.
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Hjortsjø, Carl; Jonski, Grazyna; Saxegaard, Erik & Young, Alix
(2009).
Validation of a dental erosion model I–chemical analysis in-vitro.
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An in vivo experimental model for dental erosion has been utilised to assess the effects of treating dental enamel with fluorides as a preventive and/or treatment measure. Objective: To validate the in-vivo experimental model results in-vitro using chemical analysis. Methods: Crowns of intact, surgically extracted human third molar teeth were cut into 2-4 pieces, washed (deionised water, 50% ethanol, 96% ethanol), embedded in acrylic resin and polished (grit 4000). Specimens were exposed to 5 ml of 10 mmol/L citric acid for 1 min before (etch I) and after (etch II) fluoride treatment. Aqueous solutions of TiF4, SnF2, HF and NaF (all 0.1 M F-) and deionised water (negative control) were tested (n = 6 tooth specimens/test solution). The citric acid and test solutions were applied using a peristaltic pump (flow: 6 ml/min, Gilson model Minipuls 3). Etch and fluoride solutions were collected in coded tubes and analysed blind for calcium content using atomic absorption spectrometry (Model 3300, Perkin Elmer Analytical Instruments, USA) using air-acetylene flame and λ = 422.7 nm. ∆ ppm calcium (etch I minus etch II) was calculated for each tooth and mean percentage reduction in calcium loss was determined for each test solution. Results were analysed using one way ANOVA and the Bonferroni t-test for multiple comparisons. Results: The HF- and SnF2-treatments were significantly more effective in reducing calcium dissolution than the TiF4 and NaF-treatments (p≤0.004). There was no statistical difference between TiF4 and NaF- treatments (p=0.138). The water control resulted in an increase in calcium dissolution. Conclusion: These results correlate well with results from the in vivo model and help validate the use of calcium analysis in the in-vivo dental erosion model.
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Young, Alix; Hjortsjø, Carl; Saxegaard, Erik & Jonski, Grazyna
(2009).
A study on the effect of age on enamel dissolution using a dental erosion model.
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The prevailing expert opinion suggests that there is little evidence to support the concept that pathological levels of dental erosion are age-dependant. However, some evidence seems to indicate that normal levels of erosion may be age-dependant. Many factors may contribute to this type of wear and presumably the enamel solubility is one of these factors. An in-vivo experimental model for dental erosion using volunteers of various ages has been utilised to assess the effects of treating dental enamel with fluorides to reduce damage due to erosion. The aim of the present study was to examine the possible relationship between the age of the test individuals and the degree of enamel dissolution upon acidic challenge. The in-vivo model has been described previously. In 176 test subjects (age range 18 - 69 years), labial surfaces of 342 healthy anterior teeth were exposed to 5 ml 0.18% citric acid, at 6 ml/min using a peristaltic pump. The acid was collected in coded test tubes for blind analysis of calcium content using atom absorption spectrometry. Mean calcium concentration was calculated separately for central incisors (0.924 mg/L, range 0.033-4.434) and lateral incisors (0.654 mg/L, range 0.051-3.048). The age of the subjects was not normally distributed with a mean age of 27.8 years. Statistical analysis using Spearman’s rho showed no correlation between the age of the test subjects and the calcium concentration in the acid etch (central incisors rs = 0.048, lateral incisors rs = 0.161, p<0.05). Despite the skewed age distribution these results do not support a correlation between age and degree of enamel dissolution following a brief acidic challenge.
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Hjortsjø, Carl; Dahl, Jon Einar; Saxegaard, Erik & Young, Alix
(2008).
HET-CAM testing of diluted hydrofluoric acid solutions.
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It has been suggested that diluted hydrofluoric acid (HF) solutions (≤ 0.2%) can reduce enamel dissolution in a clinical dental erosion model. The toxic effect of concentrated solutions of HF is well known. The possible effects of low concentrations of HF are less well known. This study aimed to examine the irritative effects of four HF solutions (1%, 0.2%, 0.1% and 0.05%) using the Hen’s Egg Test - chorioallantoic membrane (HET-CAM) (Kalweit et al., Toxicol in Vitro 1990;4:702-706). The hypothesis to be tested was that low concentrations of HF do not provoke any response on the blood vessels of the CAM of fertilized hens’ eggs. The CAM was accessed by careful dissection through the egg shell. 300 μl of the test solutions was dripped on the CAM under constant examination using a macroscope. The time for appearance of haemorrhage, vessel lysis and coagulation in the membrane was recorded. An average irritation score (IS) for each test solution (n=24 eggs in total) was calculated and a score was assigned: 0-0.9 = non irritant, 1-4.9 = slight irritant, 5-8.9 = moderate irritant and 9-21 = strong irritant. Mean time to coagulation (mtc100) was also calculated, values below 100 were classified as R41 - severely eye irritating. Results showed that 0.05% HF scored as slightly irritant (IS=3.26), 0.1% HF as moderately irritant (IS=7.49) while both 0.2% and 1% HF were recorded as strongly irritant (IS=9.92 and 12.22 respectively). 0.1%, 0.2% and 1% HF were classified as severe eye irritants (mtc100= 75, 80 and 50). In conclusion all four HF solutions provoked reactions on the chorioallantoic membrane of fertilized hen’s eggs. Care must therefore be taken when using diluted HF solutions under experimental clinical conditions.
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Hjortsjø, Carl; Jonski, Grazyna; Rølla, Gunnar; Thrane, Per Stanley; Saxegaard, Erik & Young, Alix
(2008).
Short term effect of NaF-, SnF2- and dilute HF-treatments on enamel erosion-like lesions in vivo.
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Dental erosion is a clinical problem in many countries today partly due to increased exposure to dietary acids. Citric acid for example is commonly found in fruit juices, mineral water, flavoured teas and bottled still water. Recent studies have shown that several acidic fluoride preparations hold promise in the prevention and treatment of dental erosion. This study aimed at comparing the effect of sodium fluoride (NaF, pH 7.3), stannous fluoride (SnF2, pH 2.9) and dilute hydrofluoric acid (HF, pH 2.0) solutions, on enamel dissolution in an experimental in vivo model as described previously (Young et al., Eur J Oral Sci 2006;114;180-183). Four healthy anterior teeth in each subject (n=29) were isolated using plastic strips and a light bodied impression material for complete palatal coverage. The labial surfaces of the test teeth were exposed to 5 ml citric acid (0.18%) using a peristaltic pump (6 ml/min), before (etch I) and 5 min after (etch II) application of test fluoride preparations. The acid was collected in a test tube for later analysis. NaF, SnF2 or HF solutions (all 0.1 M F-) were applied to the labial surfaces of the teeth for 1 min using a peristaltic pump (6 ml/min). Enamel dissolution was examined by measuring calcium content in the citric acid using atom absorption spectrometry. Mean values for etch I minus etch II were calculated and statistical analysis with the Bonferroni t-test for between group comparisons. HF and SnF2 gave mean calcium reductions of 0.37 ppm (76%) and 0.67 ppm (68%) respectively (NS). NaF gave no calcium reduction (-0.34 ppm (-52%). In conclusion, while neutral NaF had no protective effect 5 min after treatment, SnF2 and dilute HF markedly reduced calcium loss.
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Hjortsjø, Carl; Jonski, Grazyna; Saxegaard, Erik; Thrane, Per Stanley & Young, Alix
(2007).
Effect of time on dilute hydrofluoric acid-treatments of enamel in vivo.
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Dental erosion is currently considered to be one of the main reasons for tooth wear. It has been suggested in an in vivo study that hydrofluoric acid (HF) successfully reduces enamel dissolution and protects enamel against acidic challenges.
The aim of this study was to evaluate the protective effect of 0.2% HF solution over time, using a newly established indirect experimental in vivo model. Test subjects (n=28) took part in this study. Healthy anterior teeth (n=107) with intact pellicle were kept dry during the experiment using cotton rolls and saliva suction, and isolated using plastic strips and a light-bodied impression material for complete coverage of palatinal surfaces. The labial surfaces were exposed to diluted citric acid (10mmol/l) using a peristaltic pump (5ml, 6ml/min). The acid was collected in a test tube before (etch I) and after 24 h (n=54 teeth) or 7 days (n=53 teeth) (etch II), following application of aqueous 0.2% HF solution (6ml, 6ml/min). The teeth were rinsed for 5s with water after both etch I and II. Enamel dissolution was examined by assessment of calcium content in the citric acid of etch I and II using atom absorption spectroscopy. The reductions in calcium content in the citric acid between etch I and etch II were calculated for each tooth (p< 0.05). A significant reduction in post HF-treatment calcium loss was observed for both time periods, though the protective effect decreased with time. Mean percent calcium loss reduction was 49 (S.E. 3.6) for the 24-h group and 29 (S.E. 5.4) for the 7-d group. The results suggest that 0.2% HF has a protective effect on sound enamel that lasts for at least one week.
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Young, Alix; Thrane, Per Stanley; Saxegaard, Erik; Hjortsjø, Carl; Jonski, Grazyna & Rølla, Gunnar
(2006).
Preventive effects of acidic fluoride treatments on erosion-like lesions.
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Young, Alix; Thrane, Per Stanley; Saxegaard, Erik; Hjortsjø, Carl; Jonski, Grazyna & Rølla, Gunnar
(2006).
Preventive effect of acidic fluoride treatments on erosion-like lesions.
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Dental erosion is an increasingly important clinical problem and treatment of serious cases often both difficult and expensive. Prevention and treatment involving fluoride application in various forms has been studied both in vitro and in situ. Objectives: To compare the effect of acidic fluoride against neutral fluoride on erosion-like lesions using an in vivo model. Methods: Four healthy anterior teeth in each subject (n=40) with intact pellicle were individually exposed to citric acid (100mmol/l or 10mmol/l) applied using a peristaltic pump (5ml, 7ml/min) and the acid collected in test tubes before (etch I) and after (etch II) applications of the respective fluoride preparations. Fluoride toothpastes (0.15% NaF and 0.4% SnF2) were applied to the labial surfaces with a soft brush (4 x 1min) with gentle water rinsing between applications. Fluoride solutions (0.15% HF, pH 2.5 and 0.35% NaF, pH 8.8) were dripped continuously on the labial surfaces of each tooth (1 min, 4 ml/min), followed by 5 s water rinse/tooth. Subjects rested 1 min prior to etch II. Enamel solubility was examined by assessment of calcium content (Ca) in etch I and II using atom absorption spectroscopy. Results: Toothpastes – SnF2 provided far better protection of the enamel than NaF reducing Ca-loss by 20% when the weakest acid was used. NaF resulted in large Ca-loss with both acid concentrations. Solutions – HF reduced Ca-loss by 60 % whereas the NaF resulted in large Ca-loss with both acid concentrations. Conclusions: The experiments showed that SnF2 and highly dilute HF are promising preventive treatment measures for dental erosion.
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Saxegaard, Erik; Young, Alix; Hjortsjø, Carl; Jonski, Grazyna & Rølla, Gunnar
(2006).
Dentin pre-treatment with diluted hydrofluoric acid reduces solubility.
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We have previously reported that enamel and cementum are protected against dissolution in citric acid by brief pre-treatments with highly diluted hydrofluoric acid (HF, pH=3). (Saxegaard et al IADR 2005). Deposition of calcium fluoride-like material (hereafter CaF2) was shown to account for the effect which was also concentration dependent. However, advanced cases of dental erosion may penetrate the enamel and reach the dentin. Objective: To examine the effect of similar pre-treatments on the solubility of dental dentin. Methods: In 42 intact human third molars the dentin was exposed by cutting off the tooth-enamel using a diamond bur. The roots were cut off and the exposed cervical surface covered with acid-resistant nail varnish. In 6 groups each specimen was treated with 0.1M citric acid (10ml, 30min) before (etch-I) and after (etch-II) treatment with the different HF-solutions ((0.1%-1.0%, 10ml, 10min). Samples were briefly rinsed in deionised water between treatments. Dissolution of dentin was assessed by comparing the calcium content in etch I and II using atomic absorption spectroscopy. Remaining dentin samples similarly underwent etch I and various HF-treatments before examination in EDXA and SEM (Phillips type XL30 ESEM).
Results: Treatment with 0.1%HF reduced the solubility of dentin by ~80%, whereas 0.2-1.0%HF gave reductions of 93-98%. This reduction was somewhat lower than for cementum but higher than for enamel. SEM images showed that dentin was covered with a CaF2, whereas results of EDXA analyses were inconsistent. Conclusion: As with enamel and cementum the CaF2 produced on dentin in the presence of HF appears to exert a protective effect against clinical erosion. It can be speculated that the effect may be due to the low pH at which the CaF2 was formed. It seems likely that the nature of the phosphate contamination of the CaF2 determines its rate of dissolution in erosive acids.
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Hjortsjø, Carl; Jonski, Grazyna; Thrane, Per Stanley; Rølla, Gunnar & Young, Alix
(2006).
Effect of dilute hydrofluoric acid-treatments on enamel in vivo.
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Dilute hydrofluoric acid (HF) solutions have in earlier tests been proven to reduce enamel solubility. Objectives: To examine the effect of different concentrations of dilute HF in reducing enamel solubility using an in vivo model. Methods: Four healthy anterior teeth in each subject (n=72) with intact pellicle were exposed to diluted citric acid (10mmol/l) applied using a peristaltic pump (5 ml, 6 ml/min) and the acid collected in a test tube before and after application of the respective HF preparations (etch I and etch II). Four different concentrations of HF solutions (0.20%, 0.15%, 0.10%, 0.05%) where dripped on the labial surfaces of each of 18 teeth using the peristaltic pump (1 min, 6 ml/min). The teeth where rinsed for 5s with water between applications and left for five minutes after the treatment with HF before etch II. Enamel solubility was examined by assessment of calcium content in the citric acid applied before and after the treatment with the HF solutions using atom absorption spectroscopy. The reductions in calcium content in the citric acid between etch I and etch II were calculated for each tooth. Results: A greater reduction in calcium loss was observed for the three most concentrated solutions (0.20% HF – 69.7%, 0.15% HF – 61.6%, 0.15% HF – 70.1%) compared to the least concentrated solution (0.05% HF – 41.2%). Conclusions: Even extremely diluted HF seems to provide a very promising level of protection against the effects of acid on enamel solubility. Further studies are planned to determine the clinical relevance of these findings.
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Published
Nov. 10, 2010 1:46 PM
- Last modified
Nov. 16, 2023 11:50 AM
