Implant-to-nasal floor dimensions projected by panoramic radiographs in the maxillary incisor–canine region: implications for dental implant treatment

To make a comparison of panoramic radiography (PAN) and cone-beam computed tomography (CBCT) determinations of implant-to-nasal floor dimensions (INFD) in the anterior maxillary region, and to assist in determining in which tooth regions additional radiation exposure involved in CBCT scans is justifiable. Data related to INFD by PAN (PAN-D) at implant-to-nasal floor sites (central incisor, lateral incisor, canine) were gathered using 141 implant sites from 119 adult patients. INFD was estimated employing the CBCT technique as a reference method. PAN analysis equations were created for estimation of INFD by CBCT (CBCT-D) specific to implant sites. For assessment of the agreement between the PAN and CBCT methodologies, the Bland–Altman approach was employed. There were robust and significant odds ratios that implants in the canine region would fall into the underestimation groups of > 0 mm (4.5:1) (p = 0.003), > 0.5 mm (6.2:1) (p < 0.001), and > 1 mm (5.4:1) (p = 0.002). The root mean squared error (RMSE) and pure error (PE) were highest for the canine region (RMSE = 1.973 mm, PE = 2.20 mm). This research offers evidence of site-specific underestimations of available horizontal bone dimensions for implants when PAN is employed to assess the availability of vertical bone dimensions. The data suggest that it may be necessary to exclude canine regions when making assessment of INFD through PAN. Use of CBCT may, therefore, be recommended for all implant size and angulation estimations in this region.