Validation of pH cycling model to induce artificial carious lesions in bovine dentin

Introduction and objective:The purpose of the study was to evaluate different pH cycling protocols on the induction of artificial carious lesions in bovine dentin, since the most appropriate protocol to be applied is still not fully established. Material and methods: Fragments of bovine dentin (4 x 4 x 2 mm) were embedded in resin, polished and 7 mm² of each fragment was isolated with wax. The specimens were divided into three groups (A, B, C) according to the time of immersion in the demineralizing solution (1.5 ml). Group A - 15 minutes; Group B - 30 minutes; Group C - 60 minutes and subsequently immersed for 22 hours in a remineralizing solution (1.5 ml). Microhardness measurements were conducted initially, daily and after each pH cycling for 4 days. The Split-plot design (ANOVA) was applied. Results: There was a significant interaction between time and cariogenic challenge (p<0.0001). Bonferroni comparisons were executed to identify the differences over the cariogenic challenge, showing that increasing the immersion time in demineralizing solution for each pH cycling assessed, the cariogenic challenge aggressiveness increased (A

Gubernacular cord and canal: does these anatomical structures play a role in dental eruption?

Introduction: The gubernacular cord is an original structure of the dental lamina, which undergoes apoptosis and their remnants were organized in the form of epithelial islets and strands that lined up, leaving the reduced epithelium of the enamel organ towards the oral mucosa. This structure is located within the gubernacular canal, which can be identified as a small opening in the alveolar region of the lingual or palatal surface of the deciduous teeth. Objective: To conceptualize, identify and assess the possible contribution of the gubernacular cord and canal in the process of tooth eruption. Literature review: A review of literature on Pubmed, Medline and Bireme databases, without datum restriction. Little amount of scientific articles were found, and only 14 studies were identified. The authors addressed the matter succinctly, with little information about these structures, which can play an important role in the process of tooth eruption. Conclusion: The gubernacular cord and canal are anatomical structures located in the alveolar bone crest of the maxilla or mandible, behind the deciduous teeth. These structures appear to exhibit the ability to aid the eruption path of the permanent teeth successors. Despite being a relevant subject, few professionals know this structure and its possible role in the process of tooth eruption.