Facial Fenestration and Dehiscence Defects Associated With Immediate Implant Placement Without Flap Elevation in Anterior Maxillary Ridge: A Preliminary Cone Beam Computed Tomography Study

To examine cone beam computed tomography (CBCT) anatomical findings, such as the concavity of the ridge and angulation of the tooth and alveolar ridge, either facial or palatal, in order to assess the potential clinical risks of performing flapless implant surgery.CBCT images that met the inclusion criteria were examined. All images in maxillary anterior areas (canine to canine), facial bone thickness at 3 and 5 mm from the cementoenamel junction (CEJ), angulation of the tooth and alveolar ridge (Angle T: the angulation between the long axis of the tooth and the palatal plane; Angle D: the angulation between the long axis of the tooth and the midline of the ridge), the deepest point of facial concavity, the distance from the deepest point of facial concavity to the apex of the tooth and alveolar bone crest, nasopalatine canal, dehiscence, and fenestrations were measured and statistically analyzed.In total, 21 patients (12 women and 9 men) with a mean age of 55.9 years who met the inclusion criteria were included in the analysis. Data from 21 patients, 6 image sections per patient (total of 126 CBCT images) were analyzed. The mean value of facial bone thickness was 0.99 mm and 0.60 mm at 3 and 5 mm from CEJ, respectively. The distance from the deepest point of facial concavity to the apex of the tooth and alveolar bone crest was 2.79 and 11.29 mm, respectively. In canine areas, the mean values of facial bone thickness were larger at 3 mm but thinner at 5 mm. Also, canines were found to have a larger Angle D and a higher incidence of fenestration and dehiscence.Based on the findings, fenestration and a larger Angle D were associated with thinner facial bone thickness at 5 mm, and the tooth types also had an impact. Hence, for immediate implant surgery without flap elevation, besides anatomical structures, both angulation of the tooth and the alveolar ridge also need to be assessed.