Effects of STAMP Techniques and Conventional Carving on Marginal Adaptation of Class I Composite Resin Restorations: An In Vitro Study.

Background

Accurate reproduction of occlusal anatomy is a critical determinant of the clinical performance of posterior composite restorations. The present study compares marginal adaptation in Class I composite restorations completed using a Kool-Dam STAMP, a flowable-composite STAMP, or conventional hand-carving techniques.

Methods

Sixty extracted caries-free molars were randomly allocated to three experimental groups (n = 20). Two fixed marginal sites per tooth (mesial and distal) were measured at four measurement time points: immediately after restoration, before thermocycling, and after 10,000, 30,000, and 50,000 cumulative thermal cycles (5 °C/55 °C; 20 s dwell time). The two site-level values were averaged within each tooth for the primary analysis. A linear mixed-effects model included technique, measurement time point, and the technique-by-time-point interaction, with a random intercept for tooth.

Results

No significant interaction was observed between restorative technique and measurement time point, indicating that changes in marginal gap over time were not statistically significant among the three techniques (likelihood-ratio χ2(6) = 1.43, p = 0.964). The overall effect of the technique was also not significant (χ2(2) = 1.26, p = 0.532). In contrast, marginal-gap measurements increased considerably across the four measurement time points (χ2(3) = 218.52, p < 0.001), indicating progressive increases in marginal gaps with thermal ageing. Following the Holm adjustment, no pairwise comparisons between techniques at any individual time point achieved statistical significance.

Conclusions

In the present in vitro study, no statistically significant differences in marginal-gap values were detected among the Kool-Dam STAMP, flowable-composite STAMP, and conventional hand-carving techniques. The study was not designed to demonstrate equivalence or noninferiority; therefore, the absence of a statistically significant difference should not be interpreted as evidence that the techniques are equivalent. These findings suggest that the STAMP approach may be a useful technique for reproducing occlusal morphology while maintaining marginal fit. However, further clinical studies are needed to confirm its long-term performance in vivo.