[Establishment and verification of nomogram model for predicting implant-assisted bone grafting after posterior teeth alveolar ridge preservation].

Objective: Constructing a risk prediction model to assess the impact of various factors on the need for auxiliary bone grafting with implant placement following alveolar ridge preservation (ARP) in posterior teeth. Methods: According to the sample size calculation formula, the sample size was calculated using the pmsampsize package of R 4.1.3 software, based on inclusion and exclusion criteria, a total of 110 posterior teeth in 98 patients who underwent ARP at the Department of Periodontology, School and Hospital of Stomatology, China Medical University, from January 2018 to May 2024 were conducted. Teeth were randomly divided into modeling group and validation group with 7∶3 ratio according to the random number table. The modeling group was divided into direct implantation group and auxiliary bone grafting group on the basis of whether auxiliary bone grafting was performed 6 months after ARP. Univariate and multivariate analyses were conducted to identify factors influencing auxiliary bone grafting with implant placement following ARP. Nomogram was constructed using R software. Receiver operator characteristic (ROC) curve and calibration curve were drawn to evaluate model differentiation and consistency. The decision curve analysis (DCA) was used to assess the clinical application value of the model. Results: Age (OR=1.06, P=0.001), maximum attachment loss (AL) (OR=1.75, P<0.001), reason of tooth extraction (OR=12.73, P<0.001), smoking [<10 cigarettes/d (OR=7.59, P<0.001);≥10 cigarettes/d (OR=28.12, P<0.001)] and stage of periodontitis [stage Ⅱ (OR=2.57, P=0.430); stage Ⅲ (OR=21.00, P=0.007); stage Ⅳ (OR=76.50, P<0.001)] influenced the necessity for auxiliary bone grafting with implant placement after ARP. After multivariate analysis of the above influencing factors, it was found that smoking [<10 cigarettes/d (OR=7.02, P=0.009);≥10 cigarettes/d (OR=10.27, P=0.026)] was an independent risk factor for the need of auxiliary bone grafting with implant placement after ARP. The area under the ROC curve for internal verification was 0.90 (95%CI: 0.84-0.97), and the H-L goodness of fit test results were χ²=4.79, P=0.780, indicating a good agreement. The area under the externally verified ROC curve was 0.97 (95%CI: 0.92-1.00), suggesting that the fitting effect was slightly lower than that of the modeling group, and the predicted value of the model was slightly lower than the true value, which might underestimate the risk of additional surgery in patients. Results: of H-L goodness of fit test were χ²=5.03, P=0.754. The DCA curve showed that when the probability of high-risk threshold was between 0.06 and 0.93, the clinical application value of the prediction model was higher. Conclusions: Age, smoking, reason of tooth extraction, stage of periodontitis, and maximum AL of the affected teeth were related to the necessity for auxiliary bone grafting with implant placement 6 months after ARP. Smoking was an independent risk factor for auxiliary bone grafting surgery. The constructed nomogram model had good discrimination and consistency.