Adaptation Assessment of Three Bonded Resin Restorations at the Cavity Floor Using Cross-Polarization Optical...

The aim of the study was to compare the composite adaptation of three systems by using cross-polarization optical coherence tomography (CP-OCT). Most polymer-based restorations suffer from polymerization shrinkage that affects the interfacial seal. This shrinkage cannot be detected by conventional X-ray methods. Optical coherence tomography was proved to be a reliable non-invasive imaging tool to examine biological structures and biomaterials at micron scale. Twenty-four cylindrical class-V cavities were prepared on the buccal surfaces of the extracted human molars. After cavity preparation, samples were randomly divided into three groups (n = 8) according to the restoration system: one-step self-etch Clearfil Tri-S Bond Plus with Clearfil Majesty ES-2 composite (TS; Kuraray Noritake Dental), Single Bond Universal in self-etch mode with Filtek Z350 XT composite (SB; 3M ESPE), and one-step self-etch Plafique Bond with Plafique LX 5 composite (PB; Tokuyama Dental). The restoration placement was carried out according to the manufacturers' recommendations. Later, the specimens were immersed in a contrasting agent; then, image acquisitions were taken by CP-OCT to calculate the adaptation percentage by using an image analysis software. Mann-Whitney U test showed no statistical significant difference in the adaptation percentage between TS (91.72 ± 11.6) and SB (93.43 ± 6.9) groups (p > 0.05). However, the adaptation percentage in PB (41.83 ± 28.5) was significantly lower than in the other tested groups (p < 0.05). Within the limitation of the study, TS and SB groups showed better adaptation than PB. Moreover, CP-OCT is a useful imaging tool that can display composite adaptation at micron scale.