Evaluation of internal adaptation of dental adhesive restorations using micro-CT

Abstract

Objectives:The internal adaptation of composite restorations with or without resin modified glass ionomer cement (RMGIC) was analyzed non-destructively using Microcomputed tomography (micro-CT). Materials and Methods: Thirty intact human teeth were used. The specimens were divided into 3 groups. In the control group, the cavities were etched with 10% phosphoric acid for 15 sec. Composite resin was filled into the cavity without adhesive. In group 1, light cured glass ionomer cement (GIC, Fuji II LC, GC) was applied as a base. The cavities were then etched, bonded, light cured and filled with composites. In group 2, the cavities were then etched, bonded, light cured and filled with composites without base application. They were immersed in a 25% silver nitrate solution. Micro-CT was performed before and after mechanical loading. One-way ANOVA with Duncan analysis was used to compare the internal adaptation between the groups before or after loading. A paired t-test was used to compare internal adaptation before and after mechanical loading. All statistical inferences were made within the 95% confidence interval. Results: The silver nitrate solution successfully penetrated into the dentinal tubules from the pulp spaces, and infiltrated into the gap between restoration and pulpal floor. Group 2 showed a lower adaptation than the control group and group 1 (p < 0.05). There was no significant difference between the control group and group 1. For all groups, there was a significant difference between before and after mechanical loading (p < 0.05). Conclusions: The internal adaptation before and after loading was better when composites were bonded to tooth using adhesive than composites based with RMGIC. (Restor Dent Endod 2012;37(1):41-49)

Micro-CT evaluation of internal adaptation in resin fillings with different dentin adhesives

“…For the results after loading, the null hypothesis was rejected. This result was consistent with those of previous studies 14,26,27. After thermo-mechanical loading, %SP in group 2 was statistically less than that in group 4.…”

“…However, dentin adhesives were not applied in these studies, and the cavities were prepared in simple, round shapes, which has little correlation with practical situations. Recently, Kwon and Park proposed a method, in which a silver nitrate solution was penetrated from the pulp space through the dentinal tubules and the amount of silver nitrate penetration in micro-gap areas was assessed by micro-CT, and they reported that it may provide a new measure for evaluating the internal adaptation non-destructively 14. In addition, specimens could be evaluated repeatedly with micro-CT.…”

Gaps at the interface between dentine and self‐adhesive resin cement in post‐endodontic restorations quantified in 3D by phase contrast‐enhanced micro‐CT

“…Volume imaging techniques based on tomography have been used in interfacial gap studies (Bakhsh et al . , Kwon & Park , Carrera et al . ).…”

“…However, for studying restoration interfaces, nondestructive 3D approaches that maintain and reveal the spatial integrity are of great value. Volume imaging techniques based on tomography have been used in interfacial gap studies (Bakhsh et al 2011, Kwon & Park 2012, Carrera et al 2015). Yet, visibility of details is a serious concern.…”

“…Due to limited resolution, it is often difficult to distinguish between materials placed deep inside the dense structures of restored roots. The low density of most polymers precludes visualization of internal interfaces, to the extent that some researchers still use silver nitrate as a radiopaque tracer, to assess marginal gaps with laboratory micro-computed tomography (µCT) (Kwon & Park 2012, Neves et al 2014. A different method, swept source optical coherence tomography, uses laser light rather than X-rays such that interfacial defects are easier to see (Nakagawa et al 2013).…”