Arbitrarily primed-PCR detection of Streptococcus mutans and Streptococcus sobrinus in dental plaque of children with high dmft and no caries / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To isolate and identify Streptococcus mutans (Sm) and Streptococcus sobrinus (Ss) in dental plaque of children with high dmft and no caries by selective medium, biochemical methods and arbitrarily primed-polymerase chain reaction (AP-PCR).</p><p><b>METHODS</b>A total of 401 3-4-year-old children from seven kindergartens were recruited using cluster sampling and their dental caries status were examined. From 30% of children with the highest dmft score (dmft >/= 5), 20 children were chosen randomly as test group and 20 age and gender-matched caries-free children were selected as control. Plaque samples were collected from buccal surfaces of the molars and plated onto TYCSB plate. Sm and Ss were primarily identified by colony morphology and biochemical characteristics. Then chromosomal DNA of the strains was isolated and Sm or Ss were confirmed by AP-PCR.</p><p><b>RESULTS</b>The proportion positive for Sm and Ss in children with high dmft was 100% and 40% respectively while that in caries-free children was 75% and 5% by AP-PCR analysis. The differences were statistically significant between the two groups.</p><p><b>CONCLUSIONS</b>The proportions positive for Sm and Ss detected by AP-PCR method were significantly higher in children with high dmft than in caries-free children and it is a risk factor for high dmft in deciduous teeth harboring Sm and Ss.</p>

A study on oral health behavior and other related factors between children with high dmft and no caries / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To explore the risk factors of children with high dmft.</p><p><b>METHODS</b>In suburban of Guangzhou, oral health of 401 3 - 4-year-old children were examined and structured questionnaire were completed by their parents. 120 children with highest number of dmft (dmft > or = 5) and 118 caries-free children were chosen for case-control analysis.</p><p><b>RESULTS</b>The results of logistic regression analysis showed that the factors associated with high dmft were developmental defect of enamel, visible plaque index, frequency of toothbrushing, frequency of sugar consumption, and income.</p><p><b>CONCLUSIONS</b>Advocating brushing teeth at least twice daily, controlling the frequency of sugar consuming, reducing the developmental defect of enamel and paying more attention to the oral health of lower income population may effectively reduce dental caries of the children.</p>