The purpose of this study is to assess the variations induced by Clear Aligner Treatment (CAT) on the periodontal status and microbiological composition of oral microbiota. A total of 20 orthodontic patients were submitted to professional oral hygiene and, subsequently, underwent CAT (Group one, trials). A total of 20 non orthodontic patients (Group two, controls) remained untreated after oral hygiene. At T₀ (baseline) and T₁ (after 2 months), the participants were clinically examined for Probing Pocket Depth (PPD), Bleeding on Probing (BOP) and Plaque Index (PI), and microbiological tests were performed to detect bacteria of the red and orange complexes as well as the presence of Aggregatibacter actinomycetemcomitans. No significant inter- or intra-group differences were shown neither for PPD, PI and BOP (p > 0.05), nor for bacteria expressed in copies/microlitre or in percentages (p > 0.05). The only significant difference was assessed from T₀ (baseline) to T₁ (2 months) in both groups and is related to the total bacteria count increase. However, this parameter encompasses all the bacteria of the common oral microbiota, thus, not representing a significant result from a clinical point of view. Despite the limitations of this study, CAT does not significantly affect periodontal and microbiological parameters with respect to untreated patients for the first two months of therapy.

中文翻译：

---

正畸矫正器治疗过程中的微生物变化：一项前瞻性临床试验

本研究的目的是评估透明矫正器治疗 (CAT) 对口腔微生物群的牙周状况和微生物组成的影响。共有 20 名正畸患者接受了专业口腔卫生检查，随后接受了 CAT（第一组，试验）。总共 20 名非正畸患者（第二组，对照组）在进行口腔卫生后仍未接受治疗。在 T ₀（基线）和 T ₁（2 个月后），对参与者进行临床检查，包括探查袋深度 (PPD)、探查出血 (BOP) 和菌斑指数 (PI)，并进行微生物测试以检测细菌红色和橙色复合物以及聚集放线菌的存在. 没有显著间或组差异所示既不PPD，PI和BOP（p > 0.05），也不是为在拷贝/微升表达细菌或百分比（p > 0.05）。唯一的显着差异是在两组中从 T ₀（基线）到 T ₁（2 个月）评估的，并且与总细菌计数增加有关。然而，该参数涵盖了常见口腔微生物群的所有细菌，因此，从临床角度来看，并不代表显着的结果。尽管这项研究存在局限性，但在治疗的前两个月，CAT 并未显着影响未经治疗的患者的牙周和微生物参数。