Periodontal parameters of two types of 3 x 3 orthodontic retainer: a longitudinal study

ABSTRACT Introduction: bonded fixed retainers are often used to stabilize the results obtained with the orthodontic treatment. It is important that they do not prejudice dental health, as they will be used for a long period. Objective: The purpose of the present study was to compare periodontal indexes between two types of bonded fixed retainers, conventional 3 x 3 plain retainer (0.8-mm orthodontic wire, bonded to the canines only) and a manufactured braided retainer (0.2 x 0.7-mm stainless steel wire, bonded to all anterior teeth) after use. Methods: a test group of 15 volunteers (aged from 18 to 25 years) used both the conventional retainer and braided retainer for six months. A randomized longitudinal study design, with a two week washout interval, was applied. The dental plaque index, gingival index and dental calculus index were evaluated. Furthermore, the calculus accumulated along the retainer wire was measured and all patients answered a questionnaire about the use, acceptance and comfort of both types of retainers. Results: the scores for plaque and gingival indexes were higher for the braided retainer (p< 0.05) on the lingual and proximal surfaces. The same occurred with the calculus index on the lingual surfaces (p< 0.05). The calculus index along wire was higher for the braided retainer (p< 0.05). All patients preferred the conventional retainer, and said that it was also more comfortable to use. Conclusion: it was concluded that the conventional retainer showed better periodontal indexes than the braided type.

摘要
引言：粘结式固定保持器（bonded fixed retainers）常被用于巩固正畸治疗后的矫治效果。由于这类保持器需长期佩戴，确保其不会损害牙周健康至关重要。
研究目的：本研究旨在对比两种粘结式固定保持器使用后的牙周指标差异：一种为传统3×3平板式保持器（conventional 3×3 plain retainer），采用0.8mm正畸钢丝，仅粘结于尖牙；另一种为商品化编织型保持器（manufactured braided retainer），采用0.2×0.7mm不锈钢丝，粘结于所有前牙。
研究方法：本研究纳入15名年龄在18至25岁之间的志愿者，采用随机纵向研究设计，设置2周洗脱期，让每名志愿者先后佩戴两种保持器各6个月。检测指标包括牙菌斑指数（dental plaque index）、牙龈指数（gingival index）及牙结石指数（dental calculus index）；此外，还测量了保持器钢丝表面堆积的牙结石量，并要求所有受试者填写关于两种保持器的使用情况、接受度及舒适度的调查问卷。
研究结果：编织型保持器在舌面和邻面的菌斑指数与牙龈指数得分更高（p<0.05）；其舌面的牙结石指数同样更高（p<0.05）；保持器钢丝表面的牙结石量也显著高于传统型保持器（p<0.05）。所有受试者均更偏好传统保持器，且认为其佩戴更舒适。
研究结论：本研究结果表明，传统粘结式固定保持器的牙周指标表现优于编织型保持器。