Accurate evaluation of bone augmentation is essential for surgical planning in dental implantology, and it is also crucial for validating the efficiency of bone augmentation approaches. However, the prevailing evaluation methods are complicated, time-consuming, operator-dependent, and hardly reproducible, undermining their feasibility and reliability in clinic. In response to these limitations, a registration apparatus composed of a transparent orthodontic retainer and radiographic markers was developed, enabling image superimposition before and after bone augmentation. A mandibular specimen underwent cone beam computed tomography (CBCT) scans at baseline, three, and six months, with and without the apparatus. Image registrations were independently performed by two examiners using the registration apparatus and two alternative methods. Root mean square (RMS) deviations were calculated to quantify registration accuracy. Statistical analyses were conducted using ANOVA and paired t-tests. Significant differences in RMS deviations were observed between the registration methods (p = 0.002), and using the registration apparatus achieved the lowest RMS deviation (0.055 ± 0.030 mm) and consistency at different timepoints (p = 0.856) and examiners (p = 0.441). This registration apparatus demonstrated high accuracy and reproducibility in bone augmentation evaluation, making it a potential reliable tool for quantitative evaluation of bone augmentation in dental implantology.




