Analysis of caries susceptibility factors during transition from caries-free to caries in three-year-old children / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the changes of caries susceptibility factors during the transition from caries-free to caries in three-year-old children.</p><p><b>METHODS</b>The study included 144 caries-free children aged 34-38 months. All participants underwent clinical examination and full-mouth supragingival plaque collection.Survey of children's oral health behaviors involving feeding habits and oral health care was also taken from children's parents of all participants. The children were reexamined 6 and 12 months later. According to the potential changes of caries status in twelve months follow up, all the participants were divided into three groups: caries-free group (caries free children in twelve months follow up), caries at 6-month group (children who were found with caries or cavities fillings at six months review) and caries at 12-month group (children who were caries free at six months but found with caries or cavities fillings at twelve months). Streptococcus mutans (Sm)and Streptococcus sobrinus (Ss) loads were compared among the three groups by real time fluorescence quantitative polymerase chain reaction (FQ-PCR).</p><p><b>RESULTS</b>One hundred and thirty children completed twelve months review, the dropout rate was 9.7% (14/144). At the end of twelve months follow up, the number of children in caries-free group, caries at 6-month group and caries at 12-month group was 58, 44 and 28 respectively. The changes of oral behavioral habits in caries-free group, caries at 6-month group and caries at 12-month group during twelve months follow up were not significantly different (P > 0.05). At baseline, the frequency of sweets consumption and eating sweets before sleeping in caries-free group was significantly lower than that in caries at 6-month group and caries at 12-month group (P < 0.001). At baseline, the quantity of Sm and Ss in caries at 6-month group[copy number of Sm: (6.33 ± 2.21)×10(3), copy number of Ss: (1.99 ± 0.45)×10(3)] was significantly higher than that in the caries-free group[copy number of Sm: (5.81 ± 2.43)×10(3), copy number of Ss: (1.34 ± 0.53)×10(3)] (P < 0.05). There was no significant difference in the quantity of Sm and Ss in the caries-free group and caries at 12-month group(P > 0.05). At six months, the quantity of Sm and Ss in caries at 12-month group was significantly higher than that in the caries-free group although both groups of children were caries-free at six months (P < 0.05).</p><p><b>CONCLUSIONS</b>The quantity of Sm and Ss increased six months before the caries onset in three-year-old children.High frequency sweets consumption and eating sweets before sleeping were important susceptibility factors for caries onset in the future.</p>

Quantitative analysis of streptococcus mutans and its proportion in the dental plaque of different caries-susceptible children / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To determine the quantity of Streptococcus mutans (S. mutans) and the ratio of S. mutans to total bacteria in the dental plaque of different caries-susceptible children.</p><p><b>METHODS</b>Dental plaque samples from 26 children aged 3 years old to 4 years old were collected. The quantities of S. mutans and total bacteria were determined by TaqMan real-time fluorescence quantitative polymerase chain reaction (PCR). The ratio ofS. mutans to total bacteria in children with and without caries was calculated and statistically analyzed.</p><p><b>RESULTS</b>In children with and without caries, the quantities of S. mutans were 1.33 x 10(5) and 1.16 x 10(3) CFU x mg(-1), the total bacteria were 7.17 x 10(7) and 1.01 x 10(8) CFU x mg(-1), and the ratios of S. mutans to total bacteria were 0.058 6 and 0.018 6, respectively. Significant differences were observed in the quantities of S. mutans and the total bacteria as well as in the ratios of S. mutans to total bacteria of the two groups (P = 0.033, 0.418, 0.008).</p><p><b>CONCLUSION</b>The quantities of total bacteria of the two groups show negligible difference. However, the quantity of S. mutans and the ratio of S. mutans to total bacteria in caries-susceptible children are higher than those in caries-free children. Therefore, the ratios of S. mutans to total bacteria in plaque are closely associated with the prevalence of dental caries in children.</p>

Community diagnosis of dental caries in an urban community of Beijing / 中华全科医师杂志

Total 1188 subjects aged 35-74 in an urban community of Beijing were recruited by a multistage stratified random sampling procedure. Dental caries were examined by three dentists independently. The prevalence of dental crown caries was 79. 6% (DF), that of DMFS was 24. 39% and the root caries index (RCI) was 3.5% in this group. 22. 3% of the examinees required treatment for the crown caries and 26. 0% for root caries. Bivariate correlation analysis showed that DMFS was significantly correlated with RCI (P <0. 01 ), and there was no significant difference of DMFS and RCI between males and females. The study indicates that dental caries is a common health problem in adults and elderly population of urban Beijing, and the development of community oral health service system is necessary.

Thirty-nine-month xylitol chewing-gum programme in initially 8-year-old school children: a feasibility study focusing on mutans streptococci and lactobacilli.

AIM: To investigate the use of xylitol-containing chewing-gums in public elementary schools as a means to affect the growth of salivary and plaque mutans streptococci and salivary lactobacilli. DESIGN: Over a period of 24 months, 750 8- to 9-year-old children chewed xylitol (X group; n = 255) or xylitol-sorbitol (XS group; n = 264) gum on school days (454 days over 2 years), or chewed no gum at all (C group; n = 231). Consumption of xylitol in the X and the XS groups was 6.6 and 5.4g per day, respectively. Use of gum took place at school in four daily episodes of which three were supervised by teachers. Following the 24-month chewing-gum period, the subjects were re-examined after 15 months (total follow-up period: 39 months) at which time an extraneous comparison group (ExC; n = 117) was also examined. The numbers of subjects examined after 39 months were: X, 239; XS, 248; C3 217. METHODS: Salivary and plaque levels of mutans streptococci and the salivary levels of aerobically cultured aciduric bacteria (mostly representing lactobacilli) were determined using the Orion Diagnostica Dentocult SM and LB test kits, respectively. RESULTS: There were statistically significant differences after 24 and 39 months between the two xylitol chewing-gum groups and the C group with regard to salivary and plaque mutans streptococci and salivary lactobacilli: the use of xylitol-containing chewing-gums significantly reduced these bacterial scores. The reductions were statistically more significant in the X group than in the XS group. The bacterial scores of groups C and ExC were similar. CONCLUSIONS: Long-term use of xylitol-containing chewing-gum can reduce the growth of mutans streptococci in saliva and dental plaque, and lactobacilli-type bacteria in saliva, even if xylitol is used only on school days. The results also suggest that xylitol gum use can have a long-term, delayed growth-retarding effect on these micro-organisms, since reduced bacterial growth was still observed 15 months following the termination of xylitol use. The results indicate a close biochemical relationship between xylitol and mutans streptococci, and suggest that a similar relationship may exist regarding aerobically cultured aciduric bacteria present in saliva.