Association analysis of clinical aspects and vitamin D receptor gene polymorphism with external apical root resorption in orthodontic patients.

INTRODUCTION: Vitamin D is responsible for the regulation of certain genes at the transcription level, via interaction with the vitamin D receptor, and influences host immune responses and aspects of bone development, growth, and homeostasis. Our aim was to investigate the association of TaqI vitamin D receptor gene polymorphism with external apical root resorption during orthodontic treatment. METHODS: Our subjects were 377 patients with Class II Division 1 malocclusion, divided into 3 groups: (1) 160 with external apical root resorption ≤1.43 mm, (2) 179 with external apical root resorption >1.43 mm), and (3) 38 untreated subjects. External apical root resorption of the maxillary incisors was evaluated on periapical radiographs taken before and after 6 months of treatment. After DNA collection and purification, vitamin D receptor TaqI polymorphism analysis was performed by polymerase chain reaction-restriction fragment length polymorphism. Univariate and multivariate analyses were performed to verify the association of clinical and genetic variables with external apical root resorption (P <0.05). RESULTS: There was a higher proportion of external apical root resorption in orthodontically treated patients compared with the untreated subjects. In patients orthodontically treated, age higher than 14 years old, initial size of the maxillary incisor root superior to 30 mm, and premolar extraction were associated with increased external apical root resorption. Genotypes containing the C allele were weakly associated with protection against external apical root resorption (CC + CT × TT [odds ratio, 0.29; 95% confidence interval, 0.07-1.23; P = 0.091]) when treated orthodontic patients were compared to untreated individuals. CONCLUSIONS: Clinical factors and vitamin D receptor TaqI polymorphism were associated with external apical root resorption in orthodontic patients.

Analysis of the association of IL1B(C-511T) polymorphism with dental implant loss and the clusterization phenomenon.

OBJECTIVES: Endosteous dental implants consist in the treatment of choice to replace tooth loss. The knowledge that implant loss tends to cluster in subsets of individuals may indicate that host immune-inflammatory response is influenced by genetic factors. Interleukin-1 (IL-1) is a key mediator of inflammatory processes and functional polymorphisms in IL1 gene could be candidate genetic risk factors to study susceptibility to implant failure. The objective of this study was to investigate the association between IL1B (C-511T) genetic polymorphism and dental implant loss in a Brazilian population and its influence in the clusterization phenomenon. MATERIAL AND METHODS: The sample composed of 277 unrelated, both gender, mean age 53.63 ± 11.14 years individuals, divided into test group - 92 subjects with implant loss, and control group - 185 subjects with no implant loss. Patients' socioeconomic profile and clinical variables were investigated. Genomic DNA from oral mucosa was analyzed by polymerase chain reaction-restriction fragment length polymorphism. RESULTS: There was significant difference between the groups in medical treatment (P=0.040), edentulism (P=0.019), and mean number of placed implants (P=0.001). There was difference between groups with and without implant loss neither considering genotypes (P=0.279) nor alleles (P=0.168) for IL1B (C-511T) polymorphism. When individuals showing up to one implant failure (n=254) were investigated vs. patients presenting multiple implant loss (n=23), no difference was either observed between groups for genotype (P=0.083) and allele (P=0.838) frequencies. CONCLUSIONS: The borderline association of the study polymorphism with implant loss suggests further IL1 haplotype analysis to elucidate the global involvement of IL-1 proteins in the modulation of the osseointegration process.