Salivary Streptococcus mutans levels in patients with conventional and self-ligating brackets.

The objective of this study was to investigate the effect of bracket type (conventional and self-ligating) on the levels of Streptococcus mutans and total bacterial counts in whole saliva of orthodontic patients. Thirty-two male and female patients were selected using the following inclusion criteria: adolescents (mean age 13.6 years, range 11-17 years), fixed appliances in both arches, non-smoker, and no reported oral habits. Demographic and oral hygiene characteristics were determined for each subject. The patients were subdivided into two groups with random allocation of bracket type (conventional or self-ligating). An initial saliva sample was obtained before the initiation of treatment (T1) and a second sample 2-3 months following appliance bonding (T2). Salivary S. mutans and total bacteria were enumerated and analysed after growth in culture. The demographic and clinical characteristics of the samples were analysed with a t- or chi-square test, where applicable, to assess the random allocation of bracket group to participants. The results of S. mutans and total facultative bacterial counts were log transformed and statistically analysed with analysis of covariance with bracket (conventional versus self-ligating) as the categorical variable and initial total bacterial counts or initial S. mutans levels serving as the covariate. No difference was found in the demographics and oral hygiene indices between the two groups, verifying the random assignment of brackets to the population sample. The levels of S. mutans in whole saliva of orthodontically treated patients do not seem to be significantly different between conventional and self-ligating brackets. The pre-treatment levels of S. mutans are significant predictors of the levels of S. mutans after placement of orthodontic appliances, while this was not the case for total bacterial counts.

Periodontal and microbiological parameters in children and adolescents with cleft lip and /or palate.

Objective. To evaluate the oral hygiene and the periodontal condition of children and adolescents with cleft lip and/or palate (CLP). Methods. Forty-one children and adolescents, 4-18 years, with CLP and 41 normal controls participated. Clinical parameters examined were the plaque and gingival index and Community Periodontal Index of Treatment Needs. For teeth in the cleft area, probing pocket depth, bleeding on probing, and tooth mobility were also evaluated. Samples of subgingival plaque were collected from 21 randomly selected patients of each group. Results. The CLP group had generally poorer oral hygiene (plaque index significantly higher) compared with the control. Children in both groups presented mild degree of gingivitis. Teeth in the cleft area had significantly higher pocket probing depth and tooth mobility, compared with corresponding teeth in the control group. The microbial analysis did not reveal significant differences in the composition of the subgingival microbiota between groups. Teeth in the cleft presented higher isolation frequencies and mean percentages of periodontopathic bacteria. Conclusion. Youngsters with CLP showed poor oral hygiene and worse periodontal condition, compared with controls. The above results advocate their participation in an intensive preventive dental programme that should start at an early age, possibly decreasing the risk of future periodontal disease.

Adhesion of Streptococcus mutans to different types of brackets.

OBJECTIVE: To examine the difference in the adhesion of Streptococcus mutans to three different types of orthodontic brackets and the effect of the presence of an early salivary pellicle and Streptococcus sanguis on adhesion. MATERIALS AND METHODS: Three adhesion experiments were performed using stainless steel, ceramic, and plastic orthodontic brackets. In the first experiment a clinical strain of S mutans adhered to the three different types of brackets (n = 6 for each). For the second, the brackets were treated with saliva before adhesion of S mutans (n = 6 per type of bracket). Finally, the third experiment concerned saliva coated brackets (n = 6 per type of bracket), but before S mutans, S sanguis bacteria were allowed to adhere. The bacteria were always allowed to adhere for 90 minutes in all the experiments. Adhesion was quantitated by a microbial culture technique by treating the brackets with adhering bacteria with trypsin and enumerating the total viable counts of bacteria recovered after cultivation. RESULTS: There were consistently no differences in the adherence to stainless steel, ceramic, or plastic brackets. The presence of an early salivary pellicle and S sanguis reduced the number of adhering S mutans to all three types of brackets. CONCLUSIONS: Adhesion of bacteria to orthodontic brackets depends on several factors. The presence of a salivary pellicle and other bacterial species seem to have a significant effect on the adhesion of S mutans, reducing their numbers and further limiting any differences between types of brackets.