Accuracy of Implant Size Prediction Based on Edentulous Ridge Dimension on Cone-beam Computed Tomography - A Retrospective Study.

Introduction: Cone-beam computed tomography (CBCT) is the recommended imaging modality for implant planning. It is important to evaluate the accuracy of CBCT-based implant size prediction. This study aims to correlate projected implant sizes from CBCT alveolar ridge measurements with the actual sizes of placed implants, to determine the accuracy of the prediction.

Materials and methods: CBCTs taken for implant placement were included. The heights and widths of edentulous ridges were measured with Anatomage in vivo dental three-dimensional software, and actual implant size data were retrieved from treatment notes. Central incisor, canine, first premolar and first molar locations were analysed. One-way analysis of variance (ANOVA) was run to determine the average sizes for edentulous ridges and implants and Pearson correlation was conducted to determine the accuracy of CBCT-based implant size prediction.

Results: Of 544 cases analysed, the average implant diameter was 4.17 mm (standard deviation [SD] =0.38) and the length was 10.05 mm (SD =1.17). Alveolar width and height were 3.74 mm and 4.31 mm larger than the implant diameters and lengths, respectively providing approximately 1.5-2 mm of extra space on either side of the implant in relation to adjacent anatomical structures. Implants placed at mandibular canine and first molar and maxillary first premolar demonstrated significant correlations with the sizes of the edentulous ridges (P < 0.05).

Discussion: CBCT-based alveolar ridge measurements have been demonstrated as reliable parameters to predict implant sizes. However, its accuracy may be limited by the factors such as edentulous ridge morphology and proximity to vital anatomic landmarks.