Postextraction alveolar ridge preservation: biological basis and treatments

Abstract

Following tooth extraction, the alveolar ridge undergoes an inevitable remodeling process that influences implant therapy of the edentulous area. Socket grafting is a commonly adopted therapy for the preservation of alveolar bone structures in combination or not with immediate implant placement although the biological bases lying behind this treatment modality are not fully understood and often misinterpreted. This review is intended to clarify the literature support to socket grafting in order to provide practitioners with valid tools to make a conscious decision of when and why to recommend this therapy.

Figure 1

Healing of the extraction socket with and without socket grafting. When socket grafting is not adopted, major alveolar ridge resorption occurs. In a first phase, initially the blood clot, subsequently the granulation tissue and later the provisional matrix and the woven bone fill up the alveolus. The bundle bone is completely resorbed causing a reduction in the vertical ridge. In a second phase, the buccal wall and the woven bone are remodeled causing the horizontal and further vertical ridge reduction. When socket grafting is adopted, the first phase and vertical bone reduction still occur, however, the second phase and the horizontal contraction are reduced.

Figure 2

Healing of the extraction socket, with postextractive implant placement, with and without socket grafting. After tooth extraction and immediate implant placement, the blood clot fills the remaining space and the bundle bone undergoes the physiological changes. When grafting material is placed around the implant surface, filling the remaining socket area, the buccal bone wall remodeling process is corrupted, thus leading the maintenance of the horizontal ridge volume.