Effects of two sectional matrix systems on proximal contact tightness and mesiodistal dimension in class II composite restorations: an in vitro study.

OBJECTIVES: To compare the effects of two sectional matrix systems on proximal contact tightness and mesiodistal (M-D) dimension in standardised Class II mesio-occlusal (MO) composite restorations. METHODS: Twenty typodont mandibular first molar teeth (Nissin Dental Products Inc., Kyoto, Japan) received standardised Class II MO cavity preparations and were randomly allocated into two groups (n = 10 each). Group 1 received restorations with the myQuickmat Classico sectional matrix system (Polydentia SA, Mezzovico-Vira, Switzerland); Group 2 received restorations with the Septodont TDV Unimatrix R sectional matrix system (Septodont, Saint-Maur-des-Fossés, France). Anatomical plastic wedges (The Wedge, Polydentia SA, Mezzovico-Vira, Switzerland) were used gingivally in both groups. All restorations used Tetric N-Ceram nano-hybrid composite resin (Ivoclar Vivadent, Schaan, Liechtenstein). Proximal contact tightness was evaluated qualitatively using the FDI World Dental Federation clinical evaluation criteria for approximal anatomical form, assessed with dental floss and standardised stainless steel metal strips of graded thickness (25 and 50 μm). M-D dimension was measured at the occlusal and middle thirds using a digital Vernier calliper. The Shapiro-Wilk test confirmed normality of M-D data; group comparisons used the independent-samples t-test (M-D dimensions) or Mann-Whitney U-test (FDI scores). Significance was set at p < 0.05. RESULTS: Group 1 demonstrated significantly greater M-D dimensions at the occlusal third (7.07 ± 0.054 mm vs. 6.70 ± 0.082 mm; p < 0.001) and the middle third (6.93 ± 0.060 mm vs. 6.67 ± 0.080 mm; p < 0.001). FDI scores for proximal contact tightness were also significantly superior in Group 1 (median 1, range 1-2) compared with Group 2 (median 2, range 2-3) (Mann-Whitney U = 9.00; p < 0.001). CONCLUSIONS: Within the limitations of this in vitro study, the myQuickmat Classico system (Polydentia SA, Mezzovico-Vira, Switzerland) produced significantly tighter proximal contacts and greater M-D dimensions compared with the Septodont TDV Unimatrix R system (Septodont, Saint-Maur-des-Fossés, France) in Class II MO composite restorations. These findings suggest that even within the sectional category, the choice of matrix system can meaningfully influence proximal restorative outcomes. CLINICAL RELEVANCE: Selection of an appropriate sectional matrix system may influence proximal contact quality in Class II composite restorations, with implications for food impaction prevention and long-term periodontal health. The present findings may assist clinicians in making evidence-informed choices between commercially available sectional systems.