Stainless Steel Crown Size Selection Predicted by Digital Radiographic Primary Molar Measurements

Purpose: The purpose of this study was to evaluate whether preoperative radiographic measurements could predict the final steel crown selection size for restoration of primary molars. Methods: A retrospective chart review of children two to 10 years old receiving oral rehabbilitation between July 2019 and May 2020 was completed. Bitewing radiographs were used to obtain two linear radiographic measurements (coronal and cervical) using DEXIS™ Imaging Software (KaVo Dental). Separate models using each, along with covariates of primary first versus primary second molars, maxillary versus mandibular molars, and their interaction, were developed using linear regression analysis (N equals 225), treating the final crown size as a continuous response. Results: Final models utilizing stainless steel crown sizes of previously crowned teeth showed that predictors and all covariates were significant (P<0.001). Three cross-validation models (80 percent training sets) for each radiographic measurement showed strong agreement with the final models. Based on the final coronal model, a practitioner would achieve a correct fit using one, two, or three attempts with accuracy rates of 46 percent, 47 percent, and seven percent, respectively, with a cumulative rate through two attempts of 93 percent; for the cervical model, respective accuracy rates were 38 percent, 51 percent, 11 percent, and 89 percent. These models were used to create size fitting guides. Conclusion: This crown fitting guide has favorable clinical potential to assist providers, especially novice dentists, in selecting crown sizes, showing promise for expanded radiographic application in dentistry, specifically to education, technical efficiency, and minimization of waste.