The facial-coronal ridge crest alterations after single immediate implant placement and provisionalization with thin buccal plate phenotype in anterior maxilla: A radiographic case-series study

Aim: To explore the features of and potential landmarks that predict crestal ridge remodeling after immediate implant placement and provisionalization (IIPP) with thin buccal plate phenotype in the anterior maxilla. Materials and methods: Patients requiring IIPP of single maxillary incisor with thin buccal bone plate (<1 mm) were recruited. Cone-beam computed tomography (CBCT), performed before and 6 months after the intervention, were three-dimensionally superimposed. A virtual line connecting the bony emergence points of adjacent teeth was drawn as a reference. The facial-coronal alveolar crest of the extraction socket and healed ridge were located in mesial, middle and distal cross-sectional planes, and linear ridge reductions were measured. The correlation between ridge reduction and local factors was analyzed. Results: Fifty patients were included. From the extraction socket to healed ridge, the alveolar crest underwent linear bone reduction of 1.50 +/- 0.50, 1.54 +/- 0.66 and 1.65 +/- 0.73 mm in the mesial, middle, and distal regions in an apical-palatal direction. The middle region had significantly higher horizontal (facial-palatal) but lower vertical (coronal-apical) bone reduction than the mesial and distal areas (P < 0.01). The facial-coronal ridge crest of the healed ridge located close to the reference line. Ridge reduction positively correlated with the distance between the initial facial-coronal crest of the extraction socket and the reference line (P < 0.01). Conclusions: Alveolar crest of the socket lost its curvature and tended to attain a flat profile after IIPP due to inconsistent ridge reduction in middle, mesial and distal areas. The reference line may be a potential landmark for predicting the ridge crest after remodeling.