Three-Dimensional Alveolar Bone Anatomy of the Maxillary First Molars: A Cone-Beam Computed Tomography Study With Implications for Immediate Implant Placement.

Abstract

To retrospectively evaluate alveolar dimensions of healthy maxillary first molars (MFMs), which have implications for (immediate) implant placement and endodontic therapy. Cone-beam computed tomographic records of 95 patients (150 MFMs) were used [32 men and 63 men, aged 37.2 (14.9) years]. The vertical distance from sinus floor (SF) and MFM apexes (mesio-buccal [MB] and disto-buccal [DB]) and also distance between root apexes (spreading of the roots, MB to palatal and DB to palatal, representing bone width) were measured. The mean (SD) thickness of buccal and palatal bony walls (2 mm from crest) was 1.58 (0.6) mm and 1.34 (0.54) mm, respectively. The mesio-distal and bucco-lingual socket sizes at crest were 7.3 (0.84) mm and 10.5 (0.90) mm, respectively. The mean distance from SF to MFM furcation was 6.51 (2.94) mm. The mean distance (95% confidence interval) between SF and MB, DB, and palatal apexes was -0.36 mm (-0.91 to 0.19), 0.32 mm (-0.27 to 0.9), and -2.2 mm (-2.7 to -1.7), retrospectively. Significant differences were found for root apex distances to SF for MB versus palatal roots and DB roots versus palatal roots, but not for MB versus DB roots (P > 0.05). The present findings on MFM dento-alveolar morphology, in particular high intrusion of palatal roots into SF, can be used as a clinical risk management tool for immediate implant placement and endodontic therapy.