A nomogram prediction of implant apical non‐coverage on bone‐added transcrestal sinus floor elevation: A retrospective cohort study

Abstract Objectives To identify the risk indicators and develop and validate a nomogram prediction model of implant apical non‐coverage by comprehensively analyzing clinical and radiographic factors in bone‐added transcrestal sinus floor elevation (TSFE). Material and Methods A total of 260 implants in 195 patients receiving bone‐added TSFE were included in the study. The population was divided into a development (180 implants) and a validation (80 implants) cohort. According to 6 months post‐surgery radiographic images, implants were categorized as “apical non‐coverage” or “apical covered.” The association of risk factors including clinical and radiographic parameters with implant apical non‐coverage was assessed using regression analyses. A nomogram prediction model was developed, and its validation and discriminatory ability were analyzed. Results The nomogram predicting bone‐added TSFE's simultaneously placed implant's apex non‐coverage after 6 months. This study revealed that sinus angle, endo‐sinus bone gain, implant protrusion length, graft contact walls, and distal angle were predictors of implant apical non‐coverage. The generated nomogram showed a strong predictive capability (area under the curve [AUC] = 0.845), confirmed by internal validation using 10‐fold cross‐validation (Median AUC of 0.870) and temporal validation (AUC = 0.854). The calibration curve and decision curve analysis demonstrated good performance and high net benefit of the nomogram, respectively. Conclusions The clinical implementation of the present nomogram is suitable for predicting the apex non‐coverage of implants placed simultaneously with bone‐added TSFE after 6 months.