Can Orthodontic Adhesive Systems Inhibit the Formation and Development of White Spot Lesions During Fixed Orthodontic Treatment? A Systematic Review.

PURPOSE: This study aims to assess whether orthodontic bonding systems prevent orthodontic-induced white spot lesions (OIWSLs), exploring efficacy and identifying associated factors through a comprehensive systematic review of existing evidence. MATERIALS AND METHODS: The study complied to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Two evaluators screened records, and data were extracted on orthodontic bonding systems, outcomes, and participant characteristics from PubMed/MEDLINE, Cochrane Library, and EM Premium. The search equation focused on white spot lesions and orthodontic bonding. Only in-vivo studies and clinical trials on humans were included, while in-vitro studies were excluded. The risk of bias was assessed using Cochrane's RoB2 tool for RCTs and ROBINS-I tool for non-randomized studies, evaluating key domains related to bias. RESULTS: The systematic review, including 12 articles with 550 participants and 2,000 teeth, revealed that bonding with nanoparticles of nCaF2-primer and amorphous calcium phosphate-containing adhesives effectively reduced WSLs. In contrast, one-step adhesive without primer (GC Ortho Connect™) was associated with higher and more severe WSLs. Fluoride-releasing primers (Opal Seal™ and Clearfil™) did not exhibit an advantage in demineralization reduction. The inclusion of TiO2 nanoparticles in two studies yielded conflicting results on antibacterial effects. DISCUSSION: Various nanoparticles incorporated into adhesives or primers exhibit promise in preventing white spot lesions in fixed orthodontic treatment. However, the used evaluation methods, such as clinical examinations or advanced imaging, significantly impact result interpretation. The effectiveness of orthodontic adhesives in preventing WSLs should balance between biocompatibility, bond strength and demineralization control tailored to patient-specific needs.

Cytotoxic evaluation of a new ceramic-based root canal sealer on human fibroblasts.

OBJECTIVES: The purpose of this study was to evaluate the cytotoxicity of a new bioceramic-based root canal sealer (BioMM) by direct and indirect contact with human fibroblasts and to compare it with a zinc oxide-eugenol sealer, the Pulp Canal Sealer-extended working time (PCS-EWT). MATERIALS AND METHODS: Cell viability was assessed through direct and indirect contact between human fibroblasts and sealer. Direct contact was performed at 24 h, whereas the indirect contact was performed at 24 and 48 h at different concentrations: 100%, 50%, and 25%. After direct contact, 3-4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay was used and the optical density was measured by a spectrophotometer. Giemsa stain was also performed for a qualitative evaluation of the cells. STATISTICAL ANALYSIS USED: Shapiro-Wilk test was used to verify the normality of distribution of the variable. Data were analyzed by analysis of variance and Tukey tests using SPSS for Windows software 18.0. The significance level used was P < 0.05. RESULTS: Direct contact showed a significantly higher cell viability with BioMM as compared to PCS-EWT (P = 0.002). Cell viability at 24 h was significantly higher with BioMM compared to PCS-EWT for the concentrations of 50% (P = 0.004) and 25% (P = 0.003), whereas no significant difference was noted at 100% (P = 0.141). Cell viability at 48 h was significantly higher with BioMM as compared to PCS-EWT at 25% (P = 0.007). No significant difference was observed at 100% (P = 0.484) and 50% (P = 0.185). CONCLUSION: BioMM may be considered minimally cytotoxic if accidentally extruded into the periapical tissues.