Eur J Orthod. 2010 Feb;32(1):94-9. doi: 10.1093/ejo/cjp033. Epub 2009 May 27.
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.
本研究旨在探讨托槽类型（传统型和自锁型）对正畸患者全唾液中变形链球菌水平和总细菌计数的影响。采用以下纳入标准选择 32 名男女性患者：青少年（平均年龄 13.6 岁，范围 11-17 岁），双弓固定矫治器，非吸烟者，无报告的口腔习惯。确定每个患者的人口统计学和口腔卫生特征。将患者随机分为两组，分别使用传统托槽和自锁托槽。在治疗开始前（T1）获得初始唾液样本，在正畸粘接后 2-3 个月（T2）获得第二份样本。在培养后对唾液中的 S. mutans 和总细菌进行计数和分析。采用 t 检验或卡方检验分析样本的人口统计学和临床特征，以评估托槽组患者的随机分配。S. mutans 和总兼性细菌计数的结果进行对数转换，并采用协方差分析进行统计分析，托槽（传统型与自锁型）为分类变量，初始总细菌计数或初始 S. mutans 水平为协变量。两组间的人口统计学和口腔卫生指数无差异，证实了将托槽随机分配给人群样本。正畸治疗患者全唾液中的 S. mutans 水平似乎在传统托槽和自锁托槽之间没有显著差异。正畸矫治器放置前 S. mutans 的水平是放置后 S. mutans 水平的显著预测因子，而总细菌计数则不是。
