Evaluation of Proximal Contact Tightness in Anterior Resin Composite Restorations: A Comparative In Vitro Study of Injectable, Flowable, and Universal Composites.

Abstract

Aim: Proximal contact tightness (PCT) is critical for periodontal health, stability, and longevity of restorations. However, limited evidence exists comparing PCT in anterior restorations using injectable and flowable resin composites with transparent silicone indices versus universal composites with a putty index. This study compared the PCT of injectable resin composites (IJ), flowable resin composites (FL), and universal resin composites (U) in Class IV anterior restorations.

Methods: Forty-five standardized Class IV restorations were performed on typodont models by an experienced restorative dentist, divided into three groups (n = 15/group): IJ, FL, and U. Modified Fédération Dentaire International (FDI) criteria were used for qualitative assessment of PCT scores, while a digital force gauge provided quantitative measurements. Statistical analyses were performed using the chi-square test for PCT scores and Kruskal-Wallis one-way analysis of variance for PCT forces, with significance set at P < 0.05.

Results: The U group achieved the highest mean PCT force (5.05 ± 1.73 N, P < 0.01) and the highest percentage of ideal/strong PCT scores (80%-86.7%). In contrast, the IJ and FL groups demonstrated lower forces (2.07 ± 0.59 N and 2.09 ± 0.86 N, respectively) and a higher incidence of weak/inadequate contacts (20%-40% for FL; 33.33%-40% for IJ). No significant difference was found between IJ and FL groups (P > 0.05).

Conclusion: Universal composites with a putty index provide superior PCT in Class IV restorations compared to injectable and flowable composites with transparent silicone indices. Clinicians using injectable or flowable composites should consider additional adjustments to optimize PCT. Future research should validate the effects of shrinkage and variability on PCT.