Marika Koutsouri Hæreid

• Sagen, Mina Aker; Uhlig, Silvio; Holm, Heidi Vanessa; Grutle, Lene; Stangvaltaite-Mouhat, Lina & Hæreid, Marika Koutsouri [Show all 7 contributors for this article] (2025). Resin materials for 3D-printing and milling of indirect restorations – Composition and leachables using an artificial saliva model. Dental Materials. ISSN 0109-5641. p. 1–11. doi: 10.1016/j.dental.2025.10.017. Full text in Research Archive Show summary

  Abstract Objective Monomer leaching from resin-based restorations is a concern due to possible adverse effects on the oral environment. This study evaluated a validated artificial saliva model and a multi-instrument analytical workflow to characterize two liquid resins for 3D-printing, compare findings with manufacturers’ SDSs, and determine leachable profiles from test specimens incubated in artificial saliva. Methods Liquid resins (Saremco print CROWNTEC, SCT; FREEPRINT® temp, FPT) were analyzed by UHPLC–HRMS and GC–MS. Disc-shaped specimens were 3D-printed and, as control, milled from Temp Premium Flexible (TPF) (n = 6). Samples were immersed in artificial saliva (surface area-to-volume ratio 1.2 cm²/mL, 37 °C). Aliquots were analyzed for methacrylate monomers and photoinitiators after 1 h, 24 h, 1 week, and 3 months using quantitative LC–MS/MS. Specimens incubated for 24 h and 3 months were further examined by untargeted UHPLC–HRMS. Results SDSs identified BisEMA as the main methacrylate in both resins, confirmed by UHPLC–HRMS. FPT also contained nondisclosed UDMA. Targeted analysis showed significantly higher concentrations of leachables (P < 0.05) from FPT than SCT or TPF at all time points. Untargeted analysis supported this, revealing the greatest number of leachables in FPT incubations, with at least 67 putative compounds. Significance Most residual methacrylate monomers elute within 24 h after 3D-printing. However, untargeted results suggest different leaching dynamics for other substances, highlighting the importance of broader analytical approaches in assessing biocompatibility.

• 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.

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