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BACKGROUND: The "socket-shield technique" has shown its potential in preserving buccal tissues. However, front teeth often have to be extracted due to vertical fractures in buccolingual direction. It has not yet been investigated if the socket-shield technique can only be used with intact roots or also works with a modified shield design referring to vertical fracture lines. PURPOSE: The aim of this study was to assess histologically, clinically, and volumetrically the effect of separating the remaining buccal root segment in two pieces before immediate implant placement. MATERIAL AND METHODS: Three beagle dogs were selected in the study. The third and fourth premolars on both sides of the upper jaw were hemisected and the clinical crown of the distal root was removed. Then, the implant bed preparation was performed into the distal root so that a buccal segment of healthy tooth structure remained. This segment was then separated in a vertical direction into two pieces and implants placed lingual to it. After 4 months of healing, the specimens were processed for histological diagnosis. In a clinical case, the same technique was applied and impressions taken for volumetric evaluation by digital superimposition. RESULTS: The tooth segments showed healthy periodontal ligament on the buccal side. New bone was visible between implant surface and shield as well as inside the vertical drill line. No osteoclastic remodeling of the coronal part of the buccal plate was observed. The clinical volumetric analysis showed a mean loss of 0.88 mm in labial direction with a maximum of 1.67 mm and a minimum of 0.15 mm. CONCLUSION: The applied modification seems not to interfere with implant osseointegration and may still preserve the buccal plate. It may offer a feasible treatment option for vertically fractured teeth.
Bäumer et al. (Tue,) studied this question.