There is evidence for a genetic component in caries susceptibility, and studies in humans have suggested that variation in enamel formation genes may contribute to caries. For the present study, we used DNA samples collected from 1,831 individuals from various population data sets. Single nucleotide polymorphism markers were genotyped in selected genes (ameloblastin, amelogenin, enamelin, tuftelin, and tuftelin interacting protein 11) that influence enamel formation. Allele and genotype frequencies were compared between groups with distinct caries experience. Associations with caries experience can be detected but they are not necessarily replicated in all population groups and the most expressive results was for a marker in AMELX (p = 0.0007). To help interpret these results, we evaluated if enamel microhardness changes under simulated cariogenic challenges are associated with genetic variations in these same genes. After creating an artificial caries lesion, associations could be seen between genetic variation in TUFT1 (p = 0.006) and TUIP11 (p = 0.0006) with enamel microhardness. Our results suggest that the influence of genetic variation of enamel formation genes may influence the dynamic interactions between the enamel surface and the oral cavity.

Background: Genetic polymorphisms in the vitamin D receptor (VDR) gene are associated with bone homeostasis and diseases in which bone loss is a cardinal sign. The aim of this study was to determine whether chronic periodontal disease in a Brazilian population is associated with polymorphisms in the VDR gene.Methods: Clinical examination and recordings of probing depth and clinical attachment level were performed in 113 unrelated adults who were divided into two groups: 44 healthy individuals (control group) and 69 subjects with chronic periodontitis (CP). DNA was obtained from the subjects' epithelial cells by scraping the buccal mucosa. Two polymorphisms in the VDR gene were analyzed by polymerase chain reaction, followed by TaqI and BsmI restriction endonuclease digestion.Results: Frequencies of VDR/TaqI and VDR/BsmI showed significant differences between the control group and the CP group (P <0.05). The “Tb” haplotype was prevalent in the control group (43.2%), and the “TB” haplotype in the CP group (36.6%). The “TB” haplotype seemed to increase susceptibility to periodontal disease (odds ratio [OR] = 2.19). The heterozygous haplotype “TB/tb” was predominant in the CP group (OR = 4.32; P = 0.005).Conclusions:TaqI and BsmI polymorphisms of the VDR gene are associated with clinical attachment loss due to periodontal disease in a Brazilian population. These findings suggest that VDR genotype might be a risk indicator for susceptibility to chronic periodontitis. J Periodontol 2004;75:1090‐1095.

Purpose: Dental implants are currently the aesthetic and functional alternative for tooth replacement. Despite the high success rate shown by longitudinal studies, failures do occur, even in patients who present appropriate clinical conditions. The aim of the present study was to identify factors related to, or determinant of, dental implant loss in patients of the Latin-American Dental Research Institute, Curitiba, PR, Brazil. Materials and Methods: Retrospective analysis of 3578 records of patients who had implants placed in this institute during the period of 1996 to 2006 was performed. Beyond records, panoramic and periapical radiographs were analyzed. Results: Of the 3578 individuals implant treated, failures occurred in 126 (3.5%) patients (mean age 52.2 ± 10.6 years). Men lost more implants (4.5%) than did women (3.1%) (P = 0.05). Most failure occurred before loading (88.2%). Failure was more frequent when the implant was installed in the posterior jaw (58.5%). The main detectable causes of implant loss were evaluated. Most implant losses (75%) did not have an apparent clinical cause. Identified causes were 17.5% iatrogenic conditions (surgical technique, contamination, and/or occlusal trauma), poor bone quality and quantity (3%), peri-implantitis (1%), and 3.5% missing data. Conclusions: The results obtained in this study suggest that host factors can be contributing to the failure of implants.