Comparison and Evaluation of Marginal Adaptation of Interim Restorations Fabricated with Polymethylmethaacrylate Resin, Bisphenol A-Glycidçyl Methacrylate Resin and Photopolymer Resin- An In-Vitro Study

Abstract

Aim

The aim of the study is to compare and evaluate marginal adaptation of interim restorations fabricated with polymethylmethaacrylate resin, bisphenol A-glycidyl methacrylate resin and photopolymer resin.

Materials and Method:

The present study included 24 samples, divided into three groups of eight each. Group 1: Interim restorations with polymethylmethacrylate resin; Group 2: restorations with bisphenol A-glycidyl methacrylate resin; Group 3: restorations with photopolymer resin. A putty index of an unprepared mandibular molar was obtained, and a master model was prepared to fabricate 24 interim crowns. The mandibular first molar on a typodont was prepared for an all-ceramic crown with 1.5 mm occlusal reduction and 1 mm chamfer margin. An initial impression was recorded and poured with Type IV dental stone to obtain dies for interim restorations. Group 1 interim crowns were fabricated using polymethylmethacrylate resin. Impressions were made with polyvinyl siloxane putty and poured in Type IV gypsum. The cast was scanned, and 3D printed casts were obtained. Interim crowns were designed using stereolithography (ProJet 6000, 3D Systems) with light-cure biocompatible resin (VisiJet SL Clear). Printing parameters included 50 µm layer thickness, 405 nm wavelength, and 2.40 s curing per layer. Post-printing, crowns were cleaned in 99% isopropyl alcohol, dried with compressed air, and UV-cured for 90 s. Eight interim restorations were fabricated for each group.

Results

Group 1(PMMA) had the highest mean value (53.66 ± 13.18 µm) while Group 2 (Bis-GMA) showed 44.45 ± 8.67 µm. Group 3 (3D-printed resin) showed the least discrepancy (28.93 ± 3.35 µm).

Minimal overlap in confidence intervals indicated significant differences.

Overall, Group 1 showed the greatest marginal gap. Group 3 demonstrated the best marginal fit among all groups. 3D-

printed restorations showed better adaptation than PMMA.

The SMD was 24.73 (95% CI: 12.61–36.84) in favor of 3D-printed resins. Comparison with Bis-GMA also showed significance (SMD –15.52; p < 0.05).

Conclusion : Within the limitation of the study, the following conclusions drawn were that the  marginal adaptation of digitally fabricated interim crown is superior when compared to manually fabricated interim crown and the interim crowns fabricated from 3D-printed resins have better adaptation when compared to polymethylmethaacrylate resin, bisphenol A-glycidyl methacrylate resins. Hence, they can be used as a reliable alternative to other resins