Dimensional Changes in Alveolar Ridge Preservation

Alveolar Bone Loss

Objective: The objective is to evaluate the dimensional changes of soft tissue and alveolar ridge after extraction of posterior elements with different clinical protocols of alveolar preservation.

Detailed methodology: 80 individuals will be selected with need for extraction of premolar and molar elements, from both arches, for non-periodontal reasons, to participate in this randomized controlled clinical study. The dental elements will be extracted atraumatically, and allocated to one of the study groups (n=20/grp): Control Group (Ctl): alveolus closure with total flap elevation and simple suture; Group Free Gingival Mixed Graft (EGLM): closure of the alveolus without flap elevation, and placement of a mixed free gingival tissue graft (epithelialized in the central region and de-epithelialized (2 mm) in the vestibulolingual edges; Bone + Mixed Free Gum Graft Group (B+EGLM): socket closure without flap elevation, placement of lyophilized bone graft and socket sealing with mixed free gingival tissue graft (as previously described); Bone + Titanium Seal Group (B+TS): socket closure without flap elevation, placement of lyophilized bone graft, socket sealing by installing a non-absorbable titanium membrane. Immediately after the extractions, Cone Beam Computed Tomography (90 kVp/8 mA/2.3 sec) will be performed, with lip/cheek separation, with 1.5 mm thick slices and a 1 mm distance, with a field of vision (FOV) of 5±5 cm, which will be repeated after 6 months. During the CT scans, the patients will use intra-oral appliances with hyperdense indicators to determine the reference points to measure the variables: bone tissue height in the center of the socket (primary variable) and every 2 mm equidistantly; thickness of bone tissue in the center of the socket and every 2 mm equidistantly. Soft tissue variables will also be evaluated, such as: mucosal thickness at the height and 2 mm below the edge margin (by CT); height of the keratinized tissue (measured by a dry tip caliper). After 6 months, all patients will receive dental implants, with the ideal measurements for bone dimension, and the possibility of installing implants \>10mm or \<10mm in length will be statistically analyzed. After 4 months of dental implant placement, single prostheses will be installed and CT, soft tissue measurements and clinical parameters will be repeated (peri-implant depth; presence of biofilm and bleeding on probing; tissue thickness at the margin and 2 mm below; keratinized tissue). Implants will be re-evaluated after 12 months. All measurements will be performed by a previously calibrated examiner (intra-class correlation above 90%). The data will initially be analyzed in a descriptive way, with means and standard deviations. For comparison between groups and times, two-way/Tukey ANOVA test will be used. In all analyses, a significance level of 5% will be considered.

Brazil