Helen Pullisaar

• Vårum, Vegard Berg; Vandevska-Radunovic, Vaska & Pullisaar, Helen (2026). Orthodontic emergencies in a postgraduate clinic: a retrospective analysis. Acta Odontologica Scandinavica. ISSN 0001-6357. 85, s. 574–574. doi: 10.2340/aos.v85.46620. Fulltekst i vitenarkiv Vis sammendrag

  Objective: This retrospective study aimed to investigate the frequency, causes, and temporal distribution of orthodontic emergencies at the Department of Orthodontics, University of Oslo. Methods: All appointments coded as emergencies from 2015 to 2022 were reviewed and manually screened. Emergencies were classified into three categories: (1) during active treatment, (2) during retention, and (3) miscellaneous. A negative binomial generalized linear regression model was used to assess annual and monthly variations. Chi-square tests for independence were applied to analyze relationships between age group and year, gender and year, and reason for emergency. The significance level was set at p < 0.05. Results: Out of 7206 records screened, 3592 met the inclusion criteria, involving 1657 patients – 685 males (41.3%) and 972 females (58.7%). The mean number of emergencies per patient was 2.2, with no significant year-to-year variation in gender distribution. The most common age groups were 10–14 years and over 20 years. Annual emergency numbers ranged from 313 in 2015 to 638 in 2022, with statistically significant variation. Monthly variation was also significant, with July consistently having the fewest emergencies (p < 0.001). Most emergencies occurred during active treatment (n = 2021), followed by the retention phase (n = 1353), and miscellaneous reasons (n = 218). The most frequent causes were issues related to full fixed appliances and fixed retainers. Conclusions: No consistent pattern of orthodontic emergencies was observed, indicating that operator experience, the stage of postgraduate training, and seasonal fluctuations are likely the key influencing factors

• Pullisaar, Helen & Vandevska-Radunovic, Vaska (2026). Fixed or Removable? An Evidence-based Narrative Review of Orthodontic Retainer Selection and Clinical Considerations. Seminars in orthodontics. ISSN 1073-8746. doi: 10.1053/j.sodo.2026.06.006. Fulltekst i vitenarkiv
• Yang, Yang; Pullisaar, Helen; Reseland, Janne Elin & Ma, Jingzhi (2025). Molecular insights into irisin’s role in the regulation of programmed cell death: mechanisms and therapeutic potential. Journal of Molecular Medicine. ISSN 0946-2716. 104(1). doi: 10.1007/s00109-025-02623-z. Fulltekst i vitenarkiv
• Pullisaar, Helen; Cattaneo, Paolo M.; Gera, Arwa; Sankiewicz, Monika; Bilińska, Małgorzata & Vandevska-Radunovic, Vaska [Vis alle 7 forfattere av denne artikkelen] (2024). Stability, survival, patient satisfaction, and cost-minimization of CAD/CAM versus conventional multistranded fixed retainers in orthodontic patients: a 2-year follow-up of a two-centre randomized controlled trial. European Journal of Orthodontics. ISSN 0141-5387. 46(2). doi: 10.1093/ejo/cjae006. Fulltekst i vitenarkiv Vis sammendrag

  Background CAD/CAM (computer-aided design/computer-aided manufacturing) fixed retainers (FRs) as an alternative to multistranded FRs to maintain orthodontic treatment outcome. Objectives The primary aim was to compare CAD/CAM versus conventional multistranded FRs in terms of stability until 2 years. Secondary outcomes were failure rates, patient satisfaction, and cost-minimization. Trial design 2-arm parallel, two-centre randomized controlled trial. Methods Patients were randomized to CAD/CAM or conventional FRs in both arches, in a 1:1 ratio and blocks of four. Allocation concealment was secured by using sequentially numbered envelopes. Patients were blinded. FRs were bonded at the end of treatment, and patients were recalled after 12 and 24 months. First-time retainer failures were recorded and digital impressions were taken. Arch widths and lengths, as well as Little’s Irregularity Index (LII), were measured. Additionally, patients answered satisfaction questionnaires. Linear mixed models were applied for measurements and patient satisfaction. Survival analyses were estimated with Kaplan–Meier curves, along with Cox-regression modelling. Cost-minimization analysis was undertaken. Results One hundred and eighty-one patients were randomized (98 in Centre 1, and 83 in Centre 2): 90 in CAD/CAM and 91 in conventional group. One hundred and fifty three patients attended T24 follow-up. There were no significant differences in LII and arch dimensions between groups for failure-free patients. Within 24 months, 34% maxillary CAD/CAM FRs and 38% maxillary conventional FRs failed, along with 42% mandibular CAD/CAM FRs and 40% mandibular conventional FRs, with no significant difference in survival between groups (hazard ratios conventional to CAD/CAM: maxillary arch: 1.20 [P = 0.46], mandibular arch: 0.98 [P = 0.94]). There were no significant differences in patient satisfaction between groups. No harms were observed. Cost-minimization analysis showed that CAD/CAM FRs were slightly cheaper than conventional FRs. Conclusions There were no clinically significant differences in LII, arch widths, and lengths between CAD/CAM and conventional FRs after 24 months. There were no differences in failures and patient satisfaction between groups. CAD/CAM FRs were slightly cheaper than conventional FRs.

• Gamage, Thilini Hansamali Gamage Yaddehi; Grabmayr, Herwig; Horvath, Ferdinand; Fahrner, Marc; Misceo, Doriana & Louch, William Edward [Vis alle 21 forfattere av denne artikkelen] (2023). A single amino acid deletion in the ER Ca2+ sensor STIM1 reverses the in vitro and in vivo effects of the Stormorken syndrome-causing R304W mutation. Science Signaling. ISSN 1945-0877. 16(771). doi: 10.1126/scisignal.add0509. Fulltekst i vitenarkiv
• Namura, Yasuhiro; Pullisaar, Helen; Holm, Heidi Vanessa; Syverud, Morten; Mulic, Aida Gacic & Vandevska-Radunovic, Vaska (2023). Elemental composition, corrosion resistance and mechanical properties of computer-aided design and computer-aided manufacturing fixed retainers versus conventional fixed retainers. Journal of Oral Science. ISSN 1343-4934. 66(2), s. 107–110. doi: 10.2334/josnusd.23-0303. Fulltekst i vitenarkiv
• Yang, Yang; Geng, Tianxiang; Samara, Athina; Olstad, Ole Kristoffer; He, Jianying & Agger, Anne Eriksson [Vis alle 11 forfattere av denne artikkelen] (2023). Recombinant irisin enhances the extracellular matrix formation, remodeling potential, and differentiation of human periodontal ligament cells cultured in 3D. Journal of Periodontal Research. ISSN 0022-3484. 58(2), s. 336–349. doi: 10.1111/jre.13094. Fulltekst i vitenarkiv Vis sammendrag

  Abstract Background Irisin is expressed in human periodontal ligament (hPDL), and its administration enhances growth, migration and matrix deposition in hPDL cells cultured in monolayers in vitro. Objectives To identify whether irisin affects the gene expression patterns directing the morphology, mechanical properties, extracellular matrix (ECM) formation, osteogenic activity and angiogenic potential in hPDL cell spheroids cultured in 3D. Materials and Methods Spheroids of primary human hPDL cells were generated in a rotational 3D culture system and treated with or without irisin. The gene expression patterns were evaluated by Affymetrix microarrays. The morphology of the spheroids was characterized using histological staining. Mechanical properties were quantified by nanoindentation. The osteogenic and angiogenic potential of spheroids were assessed through immunofluorescence staining for collagen type I, periostin fibronectin and von Willebrand factor (vWF), and mRNA expression of osteogenic markers. The secretion of multiple myokines was evaluated using Luminex immunoassays. Results Approximately 1000 genes were differentially expressed between control and irisin-treated groups by Affymetrix. Several genes related to ECM organization were differentially expressed, and multiple deubiquitinating enzymes were upregulated in the irisin-exposed samples analyzed. These represent cellular and molecular mechanisms indicative of a role for irisin in tissue remodeling. Irisin induced a rim-like structure on the outer region of the hPDL spheroids, ECM-related protein expression and the stiffness of the spheroids were enhanced by irisin. The expression of osteogenic and angiogenetic markers was increased by irisin. Conclusions Irisin altered the morphology in primary hPDL cell-derived spheroids, enhanced its ECM deposition, mechanical properties, differentiation and remodeling potential.

• Yang, Yang; Pullisaar, Helen; Stunes, Astrid Kamilla; Nogueira, Liebert Parreiras; Syversen, Unni & Reseland, Janne Elin (2023). Irisin reduces orthodontic tooth movement in rats by promoting the osteogenic potential in the periodontal ligament. European Journal of Orthodontics. ISSN 0141-5387. 45(6), s. 842–853. doi: 10.1093/ejo/cjad021. Fulltekst i vitenarkiv Vis sammendrag

  Objectives Positive effects of irisin on osteogenic differentiation of periodontal ligament (PDL) cells have been identified previously, this study aims to examine its effect on orthodontic tooth movement (OTM) in vivo. Materials and methods The maxillary right first molars of male Wistar rats (n = 21) were moved mesially for 14 days, with submucosal injection of two dosages of irisin (0.1 or 1 μg) or phosphate-buffered saline (control) every third day. OTM was recorded by feeler gauge and micro-computed tomography (μCT). Alveolar bone and root volume were analysed using μCT, and plasma irisin levels by ELISA. Histological characteristics of PDL tissues were examined, and the expression of collagen type I, periostin, osteocalcin (OCN), von Willebrand factor (vWF) and fibronectin type III domain-containing protein 5 (FNDC5) in PDL was evaluated by immunofluorescence staining. Results Repeated 1 μg irisin injections suppressed OTM on days 6, 9, and 12. No significant differences were observed in OTM in the 0.1 μg irisin group, or in bone morphometric parameters, root volume or plasma irisin, compared to control. Resorption lacunae and hyalinization were found at the PDL-bone interface on the compression side in the control, whereas they were scarce after irisin administration. The expression of collagen type I, periostin, OCN, vWF, and FNDC5 in PDL was enhanced by irisin administration. Limitations The feeler gauge method may overestimate OTM. Conclusions Submucosal irisin injection reduced OTM by enhancing osteogenic potential of PDL, and this effect was more significant on the compression side.

• Gera, Arwa; Pullisaar, Helen; Cattaneo, Paolo M.; Gera, Shadi; Vandevska-Radunovic, Vaska & Cornelis, Marie (2022). Stability, survival, and patient satisfaction with CAD/CAM versus conventional multistranded fixed retainers in orthodontic patients: a 6-month follow-up of a two-centre randomized controlled clinical trial. European Journal of Orthodontics. ISSN 0141-5387. 45(1), s. 58–67. doi: 10.1093/ejo/cjac042. Fulltekst i vitenarkiv Vis sammendrag

  Abstract Objectives The primary aim of this two-arm parallel two-centre randomized controlled trial was to compare computer-aided design and computer-aided manufacturing (CAD/CAM) versus conventional multistranded fixed retainers (FRs) in terms of stability over 6 months. Secondary outcomes were failure rates and patient satisfaction. Methods Patients were randomized to CAD/CAM or conventional FRs in both arches, in 1:1 ratio and blocks of four. Allocation concealment was secured by using sequentially numbered envelopes. Patients were blinded. Retainers were bonded at the end of orthodontic treatment (T0), and patients were recalled after 1 (T1), 3 (T3), and 6 (T6) months. First-time retainer failures were recorded and digital impressions were taken. Arch widths and lengths, as well as Little’s Irregularity Index (LII), were measured. Additionally, patients answered satisfaction questionnaires. Linear mixed models were applied for measurements and patient satisfaction. Survival analyses were estimated with Kaplan-Meier curves, along with Cox-regression modelling. Results One hundred and eighty-one patients were randomized (98 in Centre 1, and 83 in Centre 2): Ninety in the CAD/CAM group and 91 in the conventional group. Three subjects dropped out at baseline, as they did not attend any of the follow-up appointments.168 patients attended the T6 visit. There were no significant differences in arch dimensions between T0 and T6, whilst the LII was different only in the CAD/CAM group (mean difference: 0.2 mm; 95% confidence interval: 0.1 to 0.4; P &amp;lt; 0.001). Within 6 months, 39 upper retainers (19 out of 88 CAD/CAM and 20 out of 90 conventional retainers) and 52 lower retainers failed (26 out of 88 CAD/CAM and 26 out of 90 conventional retainers), with no significant difference between the survival of both types of retainers (hazard ratios conventional to CAD/CAM: upper arch: 0.99 [P =0.99], lower arch: 0.93 [P = 0.80]). There were no significant changes in patient satisfaction between the groups. No harms were observed. Conclusions There were no clinically significant differences in LII, arch widths and lengths between CAD/CAM and conventional retainers after 6 months. There was no difference in failures and in patient satisfaction between both types of FRs. Registration ClinicalTrials.gov NCT04389879.

• Yang, Yang; Pullisaar, Helen; Landin, Maria Augusta Dos S Silva; Heyward, Catherine Anne; Schröder, Maria & Geng, Tianxiang [Vis alle 8 forfattere av denne artikkelen] (2021). FNDC5/irisin is expressed and regulated differently in human periodontal ligament cells, dental pulp stem cells and osteoblasts. Archives of Oral Biology. ISSN 0003-9969. doi: 10.1016/j.archoralbio.2021.105061. Fulltekst i vitenarkiv Vis sammendrag

  Objective To examine the expression and regulation of fibronectin type III domain-containing protein 5/irisin (FNDC5/irisin) in primary human periodontal ligament (hPDL) cells, dental pulp stem cells (hDPCs) and osteoblasts (hOBs). Methods FNDC5/irisin was identified in sections of paraffin embedded rat maxillae, cryo-sections of 3D cultured spheroids hPDL cells, hDPCs and hOBs, 2D cultured hPDL cells, hDPCs and hOBs by immunohistochemistry. The expression of FNDC5/irisin was identified by qPCR, followed by sequencing of the qPCR product. Regulation of FNDC5/irisin expression in hPDL cells, hDPCs and hOBs were evaluated after administration of different concentrations of irisin and all-trans retinoic acid (ATRA). qPCR and ELISA were used to identify expression and secretion of FNDC5/irisin in odontoblast-like differentiation of hDPCs. Results FNDC5/irisin was confirmed to be present in rat periodontium and dental pulp regions, as well as in 2D and 3D cultured hPDL cells, hDPCs and hOBs. BLAST analyses verified the generated nucleotide alignments matched human FNDC5/irisin. FNDC5/irisin gene expression was enhanced during odontoblast-like differentiation of hDPCs whereas the secretion of the protein was decreased compared to control. The protein signals in rat periodontal and pulpal tissues were higher than that of alveolar bone, and the expression of FNDC5/irisin was differently regulated by recombinant irisin and ATRA in hPDL cells and hDPCs compared to hOBs. Conclusions FNDC5/irisin expression was verified in rodent periodontium and dental pulp, and in hPDL cells, hDPCs and hOBs. The FNDC5/irisin expression was regulated by recombinant irisin and ATRA. Finally, expression and secretion of FNDC5/irisin were affected during odontoblast-like differentiation of hDPCs.

• Pullisaar, Helen; Colaianni, Graziana; Lian, Aina-Mari; Vandevska-Radunovic, Vaska; Grano, Maria & Reseland, Janne Elin (2019). Irisin promotes growth, migration and matrix formation in human periodontal ligament cells. Archives of Oral Biology. ISSN 0003-9969. doi: 10.1016/j.archoralbio.2019.104635. Fulltekst i vitenarkiv Vis sammendrag

  Objective The objective of the study was to examine the effect of irisin on human periodontal ligament cells (hPDLCs) growth, migration and osteogenic behaviour in vitro. Materials and methods Primary hPDLCs and human osteoblasts (hOBs), used as positive controls, were cultured with irisin (10 and 100 ng/ml), and effect on cell proliferation was evaluated with 5-bromo-2`-deoxyuridine incorporation at 1, 2, and 3 days, and on migration capacity was investigated by scratch assay at 2, 6, and 24 h. Osteogenic behaviour was assessed with alkaline phosphatase activity, immunoassay at 3, 7, 14, and 21 days, and confocal laser scanning microscopy at 21 days. Mineralization was examined by Alizarin red staining at 21 days. Data were compared group wise using ANOVA tests. Results Irisin induced increased proliferation of primary hPDLCs and hOBs at all time points compared to untreated controls. This was confirmed by scratch assay where irisin enhanced migration of both hPDLCs and hOBs after 6 and 24 h compared to controls. Irisin treatment promoted osteogenic behaviour of both cell types by enhancement of extracellular matrix formation. In hPDLCs irisin increased expression of type I collagen, secretion of osteoblastogenesis related proteins osteocalcin and leptin, and calcium deposition/mineralization compared to controls at 21 days. In addition, to enhance calcium deposition/mineralization in hOBs, irisin increased expression of periostin, and secretion of osteoblastogenesis related proteins osteopontin, alkaline phosphatase and osteocalcin, as compared to controls at 21 days. Conclusions Primary hPDLCs responded to irisin treatment with enhanced cell growth, migration, and matrix formation in vitro.

• Gamage, Thilini Hansamali Gamage Yaddehi; Lengle, Emma; Gunnes, Gjermund; Pullisaar, Helen; Holmgren, Asbjørn & Reseland, Janne Elin [Vis alle 16 forfattere av denne artikkelen] (2019). STIM1 R304W in mice causes subgingival hair growth and an increased fraction of trabecular bone. Cell Calcium. ISSN 0143-4160. 85. doi: 10.1016/j.ceca.2019.102110. Fulltekst i vitenarkiv
• Khanifam, Pejman; Pullisaar, Helen & Risheim, Helge (2018). Local facial atrophy and permanent anesthesia of right upper lip following subcutaneous extrusion of chlorhexidine digluconate. Oral and Maxillofacial Surgery Cases. 5(1). doi: 10.1016/j.omsc.2018.10.009. Fulltekst i vitenarkiv Vis sammendrag

  Endodontic therapy is a well-established treatment modality with a high success rate [1]. The aim of endodontic therapy is to prevent or treat periapical inflammatory lesions [2] by removal of connective tissue and microorganisms found in infected root canal [3]. In addition, it seeks an effective seal in order to prevent recolonization of the root canal system with bacteria [4]. Irrigation plays a major role in successful endodontic therapy, and it is used to remove debris from the root canal, eliminate microorganisms, and serve as a lubricant during instrumentation. Therefore, an “ideal” irrigation solution should be efficient as an antimicrobial agent but not toxic to the surrounding tissues [5]. Sodium hypochlorite (NaOCl), ethylenediaminetetraacetic acid (EDTA) and in the recent years chlorhexidine (CHX) gluconate are commonly used root canal irrigants [6]. Negative adverse effects and complications following accidental extrusion of irrigation solutions are well known in the literature for NaOCl [7,8], hydrogen peroxide [9,10] and sulfuric acid [11]. CHX has been advocated to be antimicrobial effective without having the inflammatory disadvantages of NaOCl [12,13]. To our knowledge, there have been no reports of severe tissue damage caused by 2% CHX digluconate during the course of endodontic therapy. Unique to this case report is also the unusual form of harm persistence in the aftermath of injury.

• Bizelli-Silveira, Carolina; Pullisaar, Helen; Abildtrup, Lisbeth A.; Andersen, Ole Z.; Spin-Neto, Rubens & Foss, Morten [Vis alle 7 forfattere av denne artikkelen] (2018). Strontium enhances proliferation and osteogenic behavior of periodontal ligament cells in vitro. Journal of Periodontal Research. ISSN 0022-3484. doi: 10.1111/jre.12601. Fulltekst i vitenarkiv Vis sammendrag

  Background and Objective Strontium (Sr) enhances osteogenic differentiation of certain multipotent cells. Periodontal ligament cells (PDLCs) are known to be multipotent, and Sr might be useful in periodontal bone tissue engineering. This study investigates the effect of high concentration of Sr on the proliferation and osteogenic behavior of PDLCs in vitro. Material and Methods Primary human PDLCs were cultured in MEM + 10% FBS without (Ctrl) or with Sr in four diverse concentrations: Sr1, 11.3 × 10−3 mg/L, human serum physiological level; Sr2, 13 mg/L, typical human serum level after strontium ranelate treatment; Sr3, 130 mg/L, and Sr4, 360 mg/L. The spreading area (2, 4, 6, 24 hours), proliferation rate (1, 3, 7 days), osteogenic behavior (alkaline phosphatase ‐ ALP activity, 7 and 14 days; expression of osteogenic genes, ALP, Runt‐related transcription factor 2 ‐ RUNX2, osteopontin ‐ OPN, osteocalcin ‐ OCN, and osteoprotegerin ‐OPG, 1, 3, 7, 14, 21 days), and formation of mineralized nodules (14 and 21 days) of the PDLCs were assessed. Data were compared group‐ and period‐wise using ANOVA tests. Results Periodontal ligament cells cultured with Sr4 showed increased spreading area (after 4 hours), proliferation rate (from 3 days), and OCN and OPN (from 7 days) gene expression as compared to Ctrl, Sr1, Sr2, and Sr3. Sr4 also led to lower ALP activity (from 7 days), ALP (from 3 days), and RUNX2 (at 7 and 14 days) gene expression, together with more evident formation of mineralized nodules, compared to Ctrl, Sr1, Sr2, and Sr3. Conclusion Periodontal ligament cells responded to Sr4 with increased cellular proliferation and osteogenic behavior in vitro.

• Pullisaar, Helen; Verket, Anders; Szoke, Krisztina; Tiainen, Hanna; Haugen, Håvard Jostein & Brinchmann, Jan E. [Vis alle 8 forfattere av denne artikkelen] (2015). Alginate hydrogel enriched with enamel matrix derivative to target osteogenic cell differentiation in TiO2 scaffolds. Journal of Tissue Engineering. 6. doi: 10.1177/2041731415575870. Fulltekst i vitenarkiv Vis sammendrag

  The purpose of bone tissue engineering is to employ scaffolds, cells, and growth factors to facilitate healing of bone defects. The aim of this study was to assess the viability and osteogenic differentiation of primary human osteoblasts and adipose tissue–derived mesenchymal stem cells from various donors on titanium dioxide (TiO2) scaffolds coated with an alginate hydrogel enriched with enamel matrix derivative. Cells were harvested for quantitative reverse transcription polymerase chain reaction on days 14 and 21, and medium was collected on days 2, 14, and 21 for protein analyses. Neither coating with alginate hydrogel nor alginate hydrogel enriched with enamel matrix derivative induced a cytotoxic response. Enamel matrix derivative–enriched alginate hydrogel significantly increased the expression of osteoblast markers COL1A1, TNFRSF11B, and BGLAP and secretion of osteopontin in human osteoblasts, whereas osteogenic differentiation of human adipose tissue–derived mesenchymal stem cells seemed unaffected by enamel matrix derivative. The alginate hydrogel coating procedure may have potential for local delivery of enamel matrix derivative and other stimulatory factors for use in bone tissue engineering.

• Mosti, Mats Peder; Stunes, Astrid Kamilla; Ericsson, Madelene; Pullisaar, Helen; Reseland, Janne Elin & Shabestari, Maziar [Vis alle 8 forfattere av denne artikkelen] (2014). Effects of the peroxisome proliferator-activated receptor (PPAR) delta agonist GW501516 on bone and muscle in ovariectomized rats. Endocrinology. ISSN 0013-7227. 155(6), s. 2178–2189. doi: 10.1210/en.2013-1166. Fulltekst i vitenarkiv
• Pullisaar, Helen; Reseland, Janne Elin; Haugen, Håvard Jostein; Brinchmann, Jan E. & Østrup, Esben (2014). Simvastatin coating of TiO2 scaffold induces osteogenic differentiation of human adipose tissue-derived mesenchymal stem cells. Biochemical and Biophysical Research Communications - BBRC. ISSN 0006-291X. 447(1), s. 139–144. doi: 10.1016/j.bbrc.2014.03.133. Fulltekst i vitenarkiv
• Khanifam, Pejman; Pullisaar, Helen & Leknes, Knut N. (2013). Tannimplantater i ferske ekstraksjonsalveoler. Den norske tannlegeforenings Tidende. ISSN 0029-2303. 123(3), s. 184–189. Fulltekst i vitenarkiv
• Pullisaar, Helen; Tiainen, Hanna; Landin, Maria Augusta Dos S Silva; Lyngstadaas, Ståle Petter; Haugen, Håvard Jostein & Reseland, Janne Elin [Vis alle 7 forfattere av denne artikkelen] (2013). Enhanced in vitro osteoblast differentiation on TiO2 scaffold coated with alginate hydrogel containing simvastatin. Journal of Tissue Engineering. 4, s. 1–13. doi: 10.1177/2041731413515670. Fulltekst i vitenarkiv Vis sammendrag

  The aim of this study was to develop a three-dimensional porous bone graft material as vehicle for simvastatin delivery and to investigate its effect on primary human osteoblasts from three donors. Highly porous titanium dioxide (TiO2) scaffolds were submerged into simvastatin containing alginate solution. Microstructure of scaffolds, visualized by scanning electron microscopy and micro-computed tomography, revealed an evenly distributed alginate layer covering the surface of TiO2 scaffold struts. Progressive and sustained simvastatin release was observed for up to 19 days. No cytotoxic effects on osteoblasts were observed by scaffolds with simvastatin when compared to scaffolds without simvastatin. Expression of osteoblast markers (collagen type I alpha 1, alkaline phosphatase, bone morphogenetic protein 2, osteoprotegerin, vascular endothelial growth factor A and osteocalcin) was quantified using real-time reverse transcriptase–polymerase chain reaction. Secretion of osteoprotegerin, vascular endothelial growth factor A and osteocalcin was analysed by multiplex immunoassay (Luminex). The relative expression and secretion of osteocalcin was significantly increased by cells cultured on scaffolds with 10 μM simvastatin when compared to scaffolds without simvastatin after 21 days. In addition, secretion of vascular endothelial growth factor A was significantly enhanced from cells cultured on scaffolds with both 10 nM and 10 μM simvastatin when compared to scaffolds without simvastatin at day 21. In conclusion, the results indicate that simvastatin-coated TiO2 scaffolds can support a sustained release of simvastatin and induce osteoblast differentiation. The combination of the physical properties of TiO2 scaffolds with the osteogenic effect of simvastatin may represent a new strategy for bone regeneration in defects where immediate load is wanted or unavailable.

• Rubert, Marina; Pullisaar, Helen; Gomez-Florit, Manuel; Ramis, Joana Maria; Tiainen, Hanna & Haugen, Håvard Jostein [Vis alle 8 forfattere av denne artikkelen] (2013). Effect of TiO2 scaffolds coated with alginate hydrogel containing a proline-rich peptide on osteoblast growth and differentiation in vitro. Journal of Biomedical Materials Research. Part A. ISSN 1549-3296. 101A(6), s. 1768–1777. doi: 10.1002/jbm.a.34458. Fulltekst i vitenarkiv Vis sammendrag

  The aim of this study was to investigate the effect of TiO2 scaffold (SC) coated with an alginate hydrogel containing a proline-rich peptide (P2) on osteoblast proliferation and differentiation in vitro. Peptide release was evaluated and a burst release was observed during the first hours of incubation, and then progressively released overtime. No changes were observed in the cytotoxicity after 48h of seeding MC3T3-E1 cells on the coated and uncoated TiO2 SC. The amount of cells after 7 days was higher on uncoated TiO2 SC than on alginate-coated TiO2 SC, measured by DNA content and SEM imaging. In addition, while lower expression of integrin beta1 was detected for alginate-coated TiO2 SC at this time point, similar gene expression was observed for other integrins, fibronectin-1, and several osteoblast differentiation markers. After 21 days, gene expression of integrin beta3, fibronectin-1, osterix and collagen-I was increased in alginate-coated compared to TiO2 SC. Moreover, increased gene expression of integrin alpha8, bone morphogenetic protein 2, interleukin-6 and collagen-I was found on P2 alginate-coated TiO2 SC compared to alginate-coated TiO2 SC. In conclusion, our results indicate that alginate-coated TiO2 SC can act as a matrix for delivery of proline-rich peptides increasing osteoblast differentiation.

Se alle arbeider i NVA

• Pullisaar, Helen; Cattaneo, Paolo M.; Gera, Arwa; Sankiewicz, Monika; Bilińska, Małgorzata & Vandevska-Radunovic, Vaska [Vis alle 7 forfattere av denne artikkelen] (2024). Retainere etter kjeveortopedisk behandling fremstilt med CAD⁄CAM viser likeverdige kliniske egenskaper som konvensjonelle retainere men til en lavere kostnad. Norsk tannlegeforening Tidende. doi: 10.56373/2024-9-8. Fulltekst i vitenarkiv
• Khanifam, Pejman; Pullisaar, Helen & Risheim, Helge (2020). Lokal blødtvævsatrofi i kinden og sensibilitetstab i højre side af overlæben efter subkutan ekstrusion af klorhexidindiglukonat i forbindelse med endodontisk behandling. Tandlægebladet. ISSN 0039-9353. Fulltekst i vitenarkiv
• Khanifam, Pejman; Pullisaar, Helen & Risheim, Helge (2019). Lokal bløtvevsatrofi i kinn og tap av følelse i høyre overleppe etter subkutan ekstrusjon av klorheksidindiglukonat i forbindelse med endodontisk behandling. Den norske tannlegeforenings Tidende. ISSN 0029-2303. 129, s. 706–710. Fulltekst i vitenarkiv
• Pullisaar, Helen; Verket, Anders; Szoke, Krisztina; Tiainen, Hanna; Haugen, Håvard Jostein & Brinchmann, Jan E. [Vis alle 8 forfattere av denne artikkelen] (2014). Extracellular matrix coated ceramic scaffold enhance osteoblast differentiation. Fulltekst i vitenarkiv
• Khanifam, Pejman; Pullisaar, Helen & Leknes, Knut N. (2013). Implantater i friske ekstraktionsalveoler. Tandlægebladet. ISSN 0039-9353. 117(12), s. 1002–1008. Fulltekst i vitenarkiv Vis sammendrag

  Kliniske undersøgelser har dokumenteret høj succesrate ved traditionel implantatforankret protetik. Men trods mangeårig anvendelse er der stadig udfordringer knyttet til behandling med dentale implantater. Det er fortsat vanskeligt at opnå et tilfredsstillende æstetisk resultat ved erstatning af enkelttænder i overkæbens frontregion, og ingen kan angive det ideele tidspunkt for indsættelse af implantatet efter ekstraktion. Mange patienter oplever den lange behandlingstid med dårlige midlertidige løsniger som problematisk. Placering af implantater i friske ekstraktionealveoler er en behandlingsstrategi, som efter nøje vurdering og planlægning kan benyttes ved enkelttandsimplantater. Direkte indsættelse reducerer antallet af kirurgiske indgreb, giver kortere behandlingstid og er derfor et mere patientvenligt behandlingskoncept. Observationsstudier indikerer imidlertid, at direkte indsættelse oftere mislykkes, og det kan være vanskeligt at forudsige det postoperative blødt- og hårdtvævsniveau. Alveolens morfologi kan også vanskeliggøre primær stabilitet og optimal placering af implantatet. Denne artikel ønsker med en kort gennemgang af litteraturen at præsentere fordele og ulemper ved direkte indsættelse af implantater og diskutere, hvilke kliniske vurderinger der bør foretages, før denne behandlingsform kan anbefales. To dokumenterede patienttilfælde illustrerer forskellige kirurgiske teknikker og vigtige faser ved direkte indsættelse af tandimplantater i friske ekstraktionsalveoler.

• Pullisaar, Helen; Tiainen, Hanna; Landin, Maria Augusta Dos S Silva; Lyngstadaas, Ståle Petter; Haugen, Håvard Jostein & Reseland, Janne Elin [Vis alle 7 forfattere av denne artikkelen] (2013). Local delivery of simvastatin on titanium dioxide scaffolds; a tissue engineering model. Fulltekst i vitenarkiv
• Pullisaar, Helen; Tiainen, Hanna; Landin, Maria Augusta Dos S Silva; Lyngstadaas, Ståle Petter; Haugen, Håvard Jostein & Reseland, Janne Elin [Vis alle 7 forfattere av denne artikkelen] (2013). Coating titanium dioxide scaffold with simvastatin in alginate promote osteoblast differentiation in vitro. Fulltekst i vitenarkiv
• Pullisaar, Helen; Tiainen, Hanna; Landin, Maria Augusta Dos S Silva; Lyngstadaas, Ståle Petter; Haugen, Håvard Jostein & Reseland, Janne Elin [Vis alle 7 forfattere av denne artikkelen] (2013). Enhanced in vitro bone differentiation on TiO₂ scaffold coated with simvastatin. Fulltekst i vitenarkiv
• Pullisaar, Helen; Tiainen, Hanna; Landin, Maria Augusta Dos S Silva; Lyngstadaas, Ståle Petter; Haugen, Håvard Jostein & Reseland, Janne Elin [Vis alle 7 forfattere av denne artikkelen] (2013). Local delivery of simvastatin enhances bone differentiation on porous titanium dioxide scaffold. Fulltekst i vitenarkiv
• Mosti, Mats Peder; Stunes, Astrid Kamilla; Ericsson, Madelene; Reseland, Janne Elin; Pullisaar, Helen & Shabestari, Maziar [Vis alle 8 forfattere av denne artikkelen] (2012). Effects of the peroxisome proliferator-activated receptor (PPAR) delta agonist GW501516 on bone and muscle in ovariectomized rats. Fulltekst i vitenarkiv
• Pullisaar, Helen; Reseland, Janne Elin; Lyngstadaas, Ståle Petter & Haugen, Håvard Jostein (2012). Loading and release of simvastatin from titanium dioxide scaffolds. Fulltekst i vitenarkiv
• Pullisaar, Helen; Lyngstadaas, Ståle Petter; Haugen, Håvard Jostein & Reseland, Janne Elin (2010). Permanent bone graft materials for improved implant support and bone ingrowth in alveolar defects. Fulltekst i vitenarkiv

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