Association between PAX-9 promoter polymorphisms and hypodontia in humans

Hypodontia, the congenital absence of one or a few teeth, is one of the most common alterations of the human dentition. The most common permanent missing teeth are the third molars, second premolars, and maxitlary lateral incisors. Hypodontia does not represent a serious public health problem, but it may cause masticatory and speech dysfunctions, and esthetic problems. PAX9 is believed to play an important rote in tooth development. It is expressed at initiation, bud, cap, and bell stages of odontogenesis. Mutations in PAX9 coding sequences have been implicated in autosomal dominant oligodontia affecting predominantly permanent molars and second premolars. Here, we report two polymorphisms in the promoter region of PAX9 gene that are associated with hypodontia. DNA was extracted from buccal epithelial. cells of 106 healthy Control individuals and of 102 unrelated individuals with hypodontia. PCR-RFLP was employed in the investigation of G-1031A and T-912C polymorphisms. Significant differences were obtained comparing Control and Test groups. Alleles G and T were found at a significant higher frequency in individuals with hypodontia, whereas alleles A and C were more frequent in Control subjects, p = 0.0094 and 0.0086, respectively. The GT haplotype was significantly more prevalent in the hypodontia group, white the AC haplotype was more frequent in the Control group. These results indicate that polymorphisms in the promoter region of PAX9 gene may have an influence on the transcriptional activity of this gene and are associated with hypodontia in humans. (c) 2005 Elsevier Ltd. AR rights reserved.501086187

Suggestive associations between polymorphisms in PAX9, MSX1 genes and third molar agenesis in humans

Hypodontia, the congenital agenesis of one or few permanent teeth is among the most common alterations in human dentition. Pax9 and Msx1 genes have critical roles in craniofacial development. Mutations in these genes cause severe tooth agenesis in humans and mice. The aim of the present work was to study the association of the CA repeat in the first intron of MSX1 gene and the C-160T polymorphism in the promoter region of PAX9 gene and hypodontia in humans, with emphasis on third molar agenesis. DNA extracted from buccal epithelial cells was amplified by the Polymerase Chain Reaction. Denaturing Gel Electrophoresis, DNA sequencing and PCR-RLFP were employed on the investigation of the polymorphisms. The 169 bp allele of MSX1-CA repeat was the most prevalent in both groups. Borderline associations were found for MSX1 gene. The 169-bp allele was more frequent in individuals with hypodontia (OR=1.9; 95% CI= 1.0-3.6; p=0.05) and 169/175 genotype was less prevalent in individuals with hypodontia (OR=0.4;95% CI=0.2-0.9; p=0.05). The CC genotype of the PAX9 C-160T polymorphism was found at a significant higher frequency in individuals with hypodontia (p=0.0009). A separated analysis of individuals with third molar agenesis also revealed a positive association with the CC genotype (p=0.0007).7319119

Mutans streptococci oral colonization in 12-30-month-old Brazilian children over a one-year follow-up period

Objectives: The infection levels of mutans streptococci were investigated during a one-year follow-up in children aged 12 to 30 months attending school nurseries where a sucrose-rich diet was provided. Methods: Oral levels of mutans streptococci obtained from 101 children at baseline and after a one-year follow-up were compared by age, number of teeth, feeding habits, and presence of visible plaque at baseline. Baseline predictors and changes in mutans streptococci levels during the study were compared to caries incidence after one year Results: Fluctuations in mutans streptococci levels during the follow-up period were not related to feeding habits or presence of visible plaque. Mutans streptococci levels increased after one year among children aged 12 to 24 months, while a significantly higher proportion of those aged 25-30 months showed a decrease in mutans streptococci levels during the study. Multiple logistic regression analysis suggested that high levels of mutans streptococci (greater than or equal to 100 cfu) at baseline were associated with a higher caries increment, while reduction in mutans streptococci was negatively associated with caries incidence. Conclusions: Our data suggest that despite early mutans streptococci infection and high exposure to sucrose, mutans streptococci may achieve relatively stable levels after 2 years of age. Heavy colonization by mutans streptococci in an early age was related to an extremely high caries incidence during childhood, while decreasing levels of mutans streptococci can be associated to the decrease in caries activity.61316116

Association between PAX-9 promoter polymorphisms and hypodontia in humans

Hypodontia, the congenital absence of one or a few teeth, is one of the most common alterations of the human dentition. The most common permanent missing teeth are the third molars, second premolars, and maxitlary lateral incisors. Hypodontia does not represent a serious public health problem, but it may cause masticatory and speech dysfunctions, and esthetic problems. PAX9 is believed to play an important rote in tooth development. It is expressed at initiation, bud, cap, and bell stages of odontogenesis. Mutations in PAX9 coding sequences have been implicated in autosomal dominant oligodontia affecting predominantly permanent molars and second premolars. Here, we report two polymorphisms in the promoter region of PAX9 gene that are associated with hypodontia. DNA was extracted from buccal epithelial. cells of 106 healthy Control individuals and of 102 unrelated individuals with hypodontia. PCR-RFLP was employed in the investigation of G-1031A and T-912C polymorphisms. Significant differences were obtained comparing Control and Test groups. Alleles G and T were found at a significant higher frequency in individuals with hypodontia, whereas alleles A and C were more frequent in Control subjects, p = 0.0094 and 0.0086, respectively. The GT haplotype was significantly more prevalent in the hypodontia group, white the AC haplotype was more frequent in the Control group. These results indicate that polymorphisms in the promoter region of PAX9 gene may have an influence on the transcriptional activity of this gene and are associated with hypodontia in humans. (c) 2005 Elsevier Ltd. AR rights reserved

Relationships between occlusal or free-smooth and approximal caries in mixed dentition

This cross-sectional study aimed to examine the relationships between free-smooth or occlusal surfaces and approximal. caries in 104 schoolchildren between 6 and 8 years of age. Caries diagnosis was clinically and radiographically assessed, and white spot lesions, evident caries lesions or restorations, as well as radiolucence in enamel were considered to be caries. In the studied subjects, the correlations were analyzed in the 1st primary molars (Ds), the 2nd primary molars (Es), the 1st permanent molars (6s), and all molars. The data were statistically analyzed by chi-square test. Significant correlations between occlusal surface caries and approximal surface lesions were observed in Ds and Es teeth and in all molars, but not for 1st permanent molars. For free-smooth surface, these correlations were significant only for Es and all molars. Sensitivity and specificity for occlusal surface as an indicator of approximal caries in the same tooth type ranged from 73% to 83% and 51% to 58%, respectively. Similarly, for free-smooth surface the values varied from 22% to 60% and 57% to 90%, respectively. Sensitivity and specificity for occlusal surface caries in identifying subjects with approximal caries were 78% and 70%, respectively; for free-smooth surface, the corresponding values were 59% and 65%, respectively. The results suggest that visually detected caries lesions are indicative of approximal caries. Thus, if a certain risk limit is defined and the corresponding number of caries lesions in different surfaces is reached, the risk is above the threshold and could be a practical guideline on the need for radiography in this age group of patients with 'moderate caries experience'.63530831

Relationship among Salivary Carbonic Anhydrase VI Activity and Flow Rate, Biofilm pH and Caries in Primary Dentition

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)This study aimed to determine the activity of carbonic anhydrase isoenzyme VI (CAVI) in the saliva of preschool children with caries and to investigate the relationship between caries and salivary CAVI activity, salivary flow rate and biofilm pH before and after a 20% sucrose rinse. Thirty preschool children aged 45.3-80.3 months were divided into two groups: a caries-free group and a caries group. Clinical examinations were conducted by one examiner (kappa = 0.95) according to WHO criteria (dmfs) and early caries lesions. From each subject, CAVI activity, salivary flow rate and plaque pH were determined before and after a sucrose rinse. The results were submitted to Wilcoxon, Mann-Whitney and Spearman correlation tests (alpha = 0.05). The results showed that prerinse CAVI activity and its variation were higher in the saliva from caries children than from caries-free children. No difference was found between the two groups in postrinse salivary CAVI activity. After rinsing, biofilm pH differences were lower in both groups (p = 0.0012 and p = 0.0037 for the caries and caries-free groups, respectively). Also, after the sucrose rinse, salivary flow rate significantly increased in caries and caries-free groups (p = 0.0003, p = 0.0037). The variation of salivary CAVI activity was negatively correlated with caries (r = -0.501, p = 0.005). Child's age showed a positive correlation with caries (r = 0.456, p = 0.011). These results suggest that variation of salivary CAVI activity and child's age are associated with dental caries in preschool children. Copyright (C) 2012 S. Karger AG, Basel463194200Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)FAPESP [2008/02412-6, 2008/10064-8