Background: The initial thickness of maxillary bone has significant impact on the responding level of facial bone and soft tissue after extraction and immediate implant placement. A prevailing notion is that following implant placement in fresh extraction sites, at least 2mm of facial bone is needed to prevent soft tissue recession, fenestration, and dehiscence. Purpose: The purpose of this study was to use cone beam computed tomography (CBCT) to measure horizontal width of facial alveolar bone overlying healthy maxillary central incisors and to determine prevalence of bone thickness ≥2mm. Materials and Methods: Tomographic data from 101 randomly selected patients were evaluated by two independent observers. Assessments were made of facial bone width at levels 1.0 to 10.0mm apical to the bone crest. Results: Healthy maxillary central incisors (n=202) were measured from 101 patient scans. The percent of teeth with facial bone ≥2mm at levels 1, 2, 3, 4, and 5mm from the bone crest was 0, 1.5, 2.0, 3.0, and 2.5%, respectively. Overall mean thickness of the bone was 1.05mm for right and left central incisors combined. The range of individual measurements for all levels was 0 to 5.1mm. The occurrence of ≥2mm thickness bone measurements increased with increasing depth. However, mean widths observed at levels 6 to 10mm from the crest ranged only 1.0 to 1.3mm because of apparent fenestration occurrence (0mm bone) in approximately 12% of teeth. Overall, no significant differences in bone thickness were found between ethnic, gender, age, or scan groups. Conclusions: Using CBCT, occurrences of ≥2mm maxillary facial alveolar bone were found on no more than 3% of root surfaces 1.0 to 5.0mm apical to the bone crest in this sample of maxillary central incisors. The study evidenced prevalence of a thin facial alveolar bone (<2mm) that may contribute to risk of facial bone fenestration, dehiscence, and soft tissue recession after immediate implant therapy.
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