This study investigated possible prenatal and neonatal variables that may influence the prevalence of tooth enamel hypoplasia in preterm and low birth weight children (LBW) and a matched control group of term children with normal birth weight (NBW). The study sample consisted of 61 children born preterm and with LBW examined at 18-34 months of age. The control group was formed by 61 infants born full term and with NBW examined at 31-35 months of age. All children were born at the Center of Integrated Attention of Women's Health (CAISM-UNICAMP). FDI criteria were followed for dental examination. Medical data was collected retrospectively from hospital records. Among preterms, 57.4% had some type of developmental defects of enamel (DDE), 52.5 % had opacities and 21.3 % presented hypoplasia. Among full-term children, 24.6% presented DDE, 24.6% had opacities and 3.3% had hypoplasia. LBW preterm infants presented a higher prevalence of hypoplasia than NBW controls. The deciduous teeth most affected by hypoplasia were maxillary incisors. There was no significant association with prenatal variables; among neonatal variables there was a significant association with respiratory distress syndrome and neurological examination at discharge with an altered result.

PURPOSE: Hypodontia is the congenital absence of one or more (up to six) permanent and/or deciduous teeth, being one of the most common alterations of the human dentition. Genetic polymorphisms are variations of DNA sequences occurring in a population. This study investigated whether G-915C single nucleotide polymorphism (SNPs) in the PAX9 gene promoter is associated with hypodontia in humans. MATERIAL AND METHODS: The polymorphism in region G/C-915 of PAX9 gene (NCBI ref SNP ID: rs 2073247) of 240 patients was analyzed, being 110 controls and 130 individuals with third molar agenesis. After DNA extraction, the region of interest was amplified by PCR technique using two different primers. The significance of the differences in observed frequencies of polymorphisms in both groups was assessed by odds-ratio and chi-squared test with 95% confidence interval. RESULTS: Genotype CC was more frequent in patients with agenesis (11.5%) compared to the control (1.8%), while GG was more prevalent in the control group (39.1%) compared to the individuals with agenesis (26.2%). CONCLUSION: These data showed that the allele C could be associated with the third molar agenesis.

O presente estudo teve por objetivo analisar a expressão das metaloproteases da matriz extracelular durante a atrofia experimental das glândulas submandibulares em ratos, causada pela obstrução do ducto excretor principal. Os zimogramas realizados com extratos das porções internas e externas das glândulas salivares normais e ligadas mostraram que as principais enzimas gelatinolíticas possuíam pesos moleculares variando entre 72 kDa e 65 kDa. A atividade dessas enzimas aumentou progressivamente até o período entre 5 e 10 dias após a ligação, decrescendo nos períodos subseqüentes. Foram também detectadas bandas migrando entre 92 kDa e 72 kDa, sendo essas enzimas detectadas em quantidades significativas apenas na região da cápsula da glândula, no período de 2 dias. A confirmação de que as enzimas detectadas eram metaloproteases foi feita pelo uso de inibidores específicos. Os resultados sugerem que as metaloproteases da matriz têm um papel importante na remodelação da matriz extracelular durante a atrofia experimental da glândula submandibular.

The purpose of the present study was to analyze the expression of the major metalloproteases in normal and ligated glands. The major metalloproteases detected had a molecular weight ranging from 72 to 65 kDa. The gelatinolytic activity increased progressively reaching a peak between 5 and 10 days after ligation. Bands with molecular weight ranging from 92-80 kDa were also detected in the capsule of the gland. The 92-80 kDa enzymes were only detected 2 days after ligation. The activity of these enzymes was supressed by specific inhibitors. Our results show that matrix metalloproteases play an active role in the extensive remodeling of the connective tissue that occurs during the atrophy of the submandibular gland.