Dimensional changes of buccal bone plate in immediate implants inserted through open flap, open flap and bone grafting, and flapless technique. A CBCT randomized controlled clinical trial

OBJECTIVES: To assess through cone-beam computed tomography (CBCT) buccal alveolar bone alterations after immediate implant placement using the following techniques: open flap and grafting (flap-graft), open flap and no grafting (flap-nograft) and flapless and no grafting (noflap-nograft). MATERIALS AND METHODS: This was a three-armed parallel group randomized clinical trial with allocation ratio 1:1:1. Patients were eligible in case they needed immediate implant replacing teeth in maxillary premolar area, with sufficient buccal bone support. CBCT was performed immediately after the intervention and 6 months later. The main outcomes were CBCT measurements performed at apical (A-EA), medial (M-EM) and external and internal implant bevel level (B-EB, B-IB) and vertical defect depth (DP). Pain and discomfort, time of surgery and complications were recorded. Differences between groups were estimated through ANOVA tests and post-hoc Scheffe's analysis for pairwise comparisons. Multiple regressions were conducted to estimate influence of gingival biotype and baseline marginal gap dimension. RESULTS: Forty-five patients were recruited and randomized to treatments with one lost to follow-up. Analysis of variance showed that the effect of treatment technique was not relevant for all horizontal and vertical outcomes. The three techniques exhibited almost complete fill of marginal gap, with a mean residual vertical gap of 0.27 mm and horizontal gap of 0.5 mm. Regression models indicated a positive effect of thick biotype on gap filling and dimensional bone reduction. The noflap-nograft technique resulted less painful. CONCLUSIONS: The option of noflap-nograft surgery in post-extraction implants allows for minimal surgical intervention with comparable buccal bone changes and gap filling after a follow-up of 6 months in sites with sufficient buccal bone support.