The purpose of this retrospective study was to evaluate bone healing after autogenous demineralized dentin matrix (DDM) grafts, focusing on the distal root of the mandibular second molar after the extraction of the third. We included retrospective data from 20 patients who had undergone molar extractions (15 male, 41.9 ± 12.0 years) between January 2020 and September 2022 and had DDM grafts implanted on the extraction socket, immediately ("immediate graft") or 6 weeks ("delayed graft") after the first surgery without primary closure. Patients who underwent grafting on only one side were used as the control group (n = 4). Bone defects at the mandibular second molar were measured preoperatively and 4 months after the graft surgery using cone-beam computed tomography (CBCT). Improvement of bone defect (i.e., the change in the bony defect pre- vs. postoperatively) was compared between the control and graft groups using the Wilcoxon Signed Rank test, and the difference between immediate and delayed grafts was analyzed with the Mann-Whitney U test. Complications such as infections or graft failure did not occur. Although pre-operative defects were smaller in the control than in the graft group (2.98 ± 1.77 and 10.02 ± 3.22 mm, p = 0.001), post-operative defects were similar in both (2.12 ± 0.59 and 2.29 ± 1.67 mm, respectively). The improvement ratio was not statistically significant in the control group (22.68 ± 15.36%) but a difference was observed in the graft group (76.70 ± 15.36%, p = 0.001). The amount of improvement of bone defect was not affected by graft timing or patient sex. In conclusion, DDM can improve bone defect at the distal aspect of the mandibular second molar after third molar extraction.
Keywords: bone graft substitutes; demineralized dentin matrix; third molar; tooth extraction.