Effect of thickness of indirect restoration and distance from the light-curing unit tip on the hardness of a dual-cured resin cement

This study evaluated the Knoop hardness and polymerization depth of a dual-cured resin cement, light-activated at different distances through different thicknesses of composite resin. One bovine incisor was embedded in resin and its buccal surface was flattened. Dentin was covered with PVC film where a mold (0.8-mm-thick and 5 mm diameter) was filled with cement and covered with another PVC film. Light curing (40 s) was carried out through resin discs (2, 3, 4 or 5 mm) with a halogen light positioned 0, 1, 2 or 3 mm from the resin surface. After storage, specimens were sectioned for hardness measurements (top, center, and bottom). Data were subjected to split-plot ANOVA and Tukey's test (α=0.05). The increase in resin disc thickness decreased cement hardness. The increase in the distance of the light curing tip decreased hardness at the top region. Specimens showed the lowest hardness values at the bottom, and the highest at the center. Resin cement hardness was influenced by the thickness of the indirect restoration and by the distance between the light-curing unit tip and the resin cement surface.Piracicaba Dental School State University of Campinas, Piracicaba, SPDepartment of Dental Materials and Prosthodontics São José dos Campos Dental School São Paulo State University, São José dos Campos, SPDepartment of Restorative Dentistry Piracicaba Dental School State University of Campinas, Piracicaba, SPDepartment of Pediatric Dentistry Piracicaba Dental School State University of Campinas, Piracicaba, SPDepartment of Dental Materials and Prosthodontics São José dos Campos Dental School São Paulo State University, São José dos Campos, S

Degree of cure and monomer leaching from orthodontic adhesive resins: In vitro and in vivo evidence

The aim of this review article is to summarize the recent in vitro and in vivo evidence in the field of degree of conversion and the monomer leaching from orthodontic adhesive resins. Analysis of the material is structured around the presentation of evidence summarizing the current status in this field. The degree of cure of polymer adhesives modulates the physical and mechanical properties of the material, particularly solubility and degradation and for these reasons are of scientific interest. The leached components from resinous materials, which are related to the degree of cure of the resin, is of important biological interest and has raised serious concern for the possible biological adverse effects in different systems and organs. This paper includes a presentation of techniques used to study the degree of cure and monomer leaching, currently available data from in vitro and in vivo research approaches and the potential clinical impact of in vivo findings. © 2010 Elsevier Inc

Detection Methods for Early Caries Diagnosis: A Systematic Review and Meta-Analysis

The aim was to appraise the evidence on the performance of various means for the detection of incipient caries in vivo. Five databases of published and unpublished research were searched for studies from January 2000 to October 2019. Search terms included "early caries"and "caries detection."Inclusion criteria involved diagnostic test accuracy studies for early caries detection in permanent and primary teeth. A risk-of-bias assessment was performed using the QUADAS-2 tool. We performed the study selection, data extraction, and risk-of-bias assessment in duplicate. The review protocol was a priori registered in the Open Science Framework. Of the initially 22,964 search results, 51 articles were included. For permanent teeth, when histologic examination was considered as the reference for occlusal surfaces, the sensitivity (Se) range appeared high for the DIAGNOdent Pen (DD Pen) at 0.81-0.89, followed by ICDAS-II at 0.62-1, DIAGNOdent (DD) at 0.48-1, and bitewing radiography (BW) at 0-0.29. The corresponding specificity (Sp) range was: DD Pen 0.71-0.8, ICDAS-II 0.5-0.84, DD 0.54-1, and BW 0.96-1. When operative intervention served as the reference for occlusal surfaces, again, the DD means valued the most promising results on Se: DD 0.7-0.96 and DD Pen 0.55-0.90, followed by ICDAS-II 0.25-0.93, and BW 0-0.83. The Sp range was: DD 0.54-1, DD Pen 0.71-1, ICDAS-II 0.44-1, and BW 0.6-1. For approximal surfaces, the Se was: BW 0.75-0.83, DD Pen 0.6, and ICDAS-II 0.54; the Sp was: BW 0.6-0.9, DD Pen 0.2, and ICDAS-II 1. For primary teeth, under the reference of histologic assessment, the Se range for occlusal surfaces was: DD 0.55-1, DD Pen 0.63-1, ICDAS-II 0.42-1, and BW 0.31-0.96; the respective Sp was: DD 0.5-1, DD Pen 0.44-1, ICDAS-II 0.61-1, and BW 0.79-0.98. For approximal surfaces, the Se range was: DD Pen 0.58-0.63, ICDAS-II 0.42-0.55, and BW 0.14-0.71. The corresponding Sp range was: DD Pen 0.85-0.87, ICDAS-II 0.73-0.93, and BW 0.79-0.98. Se and Sp values varied, due to the heterogeneity regarding the setting of individual studies. Evidently, robust conclusions cannot be drawn, and different diagnostic means should be used as adjuncts to clinical examination. In permanent teeth, visual examination may be enhanced by DD on occlusal surfaces and BW on approximal surfaces. In primary teeth, DD Pen may serve as a supplementary tool across all surfaces. © 2021 S. Karger AG, Basel