Abstract: PURPOSE: To analyze the relationship between the changes of saliva flow velocity, total protein and dental plaque before and after orthodontic treatment. METHODS: The clinical data of 80 patients who received orthodontic treatment in Huaibei Miners General Hospital from May 2021 to February 2024 were retrospectively analyzed.Six months after treatment, the patients were divided into low-level group (n=39) and high-level group (n=41) according to the median plaque index. The clinical data of the high-level group and the low-level group were compared to analyze the influencing factors of high dental plaque index in orthodontic patients. The predictive value of △saliva flow velocity(before treatment -after 6 months of treatment), △total protein and their combination on high dental plaque index in orthodontic patients was analyzed.SPSS 25.0 software package was used for statistical analysis of the data. RESULTS: Six months after treatment, the saliva flow velocity and total protein level of orthodontic patients were significantly lower than before treatment (P<0.05). The soft scale index, △saliva flow velocity and △total protein level in high-level group were significantly higher than those in low-level group (P<0.05). Logistic regression analysis showed that △saliva flow velocity(OR=4.604, 95%CI: 2.024-10.474) and △ total protein(OR=3.554, 95%CI: 1.562-8.084) were the influencing factors of high dental plaque index (P<0.05).The area under the curve (AUC) of △ saliva flow velocity, △total protein and their combination in predicting high dental plaque index in orthodontic patients were 0.803, 0.799 and 0.905 (P<0.05), respectively, and the AUC value of the combination was higher(P<0.05). CONCLUSIONS: △Saliva flow velocity and △total protein can be used to predict high dental plaque index after orthodontic treatment, and their combination has higher predictive value.

Key words: Saliva flow velocity, Total protein, Plaque index, Orthodontic treatment, Predictive value