Autogenous Dentin Graft for Alveolar Ridge Preservatio

Following tooth extraction, the alveolar ridge undergoes progressive dimensional changes,primarily due to bundle bone resorption, which may compromise the volume and quality ofbone available for future implant placement. Alveolar ridge preservation (ARP) proceduresaim to minimize this resorption through the use of various grafting materials.This prospective, randomized, controlled clinical trial was conducted at the Departmentof Oral and Maxillofacial Surgery, Faculty of Dentistry, Ankara Yıldırım BeyazıtUniversity. Eligible participants were systemically healthy individuals aged ≥18 years(ASA I‐II) who required extraction of a radiographically non‐infected tooth. Patientswith acute infection at the extraction site, advanced systemic disease, use ofmedications affecting bone metabolism, smoking or alcohol consumption, or anticipatednon‐compliance with follow‐up visits were excluded.A total of 56 extraction sockets from nine patients (six women and three men; age range,24‐55 years) were randomly allocated into four groups: Control (spontaneous healingwithout grafting, n = 13), Dentin (grafted with autogenous dentin particles, n = 14),Dentin + PRF (grafted with autogenous dentin combined with leukocyte‐ and platelet‐richfibrin, n = 15), and FDBA (grafted with freeze‐dried bone allograft, n = 14). Allsurgical procedures were performed by the same operator to eliminate inter‐operatorvariability.The sample size was calculated using G*Power version 3.1.9.6 (Universität Kiel, Germany),based on a repeated‐measures ANOVA design, an effect size of 0.20, a statistical power of80%, and an alpha level of 0.05. The analysis indicated that a minimum of 52 extractionsockets (13 per group) was required.Autogenous dentin grafts were prepared immediately after extraction according to themethod described by Binderman et al. Soft‐tissue remnants, enamel, and cementum wereremoved from the extracted teeth using a tungsten carbide bur under water cooling. Thecleaned teeth were processed using a Smart Dentin Grinder (KometaBio, Israel) to obtainparticulate graft material with a particle size of 300‐1200 µm. The particles weresubsequently disinfected for 10 min in a solution containing 20% ethanol and 0.5 M NaOHand rinsed with a buffered saline solution to neutralize the pH before graft placement.For the Dentin + PRF group, platelet‐rich fibrin was prepared from 10 mL of venous bloodcollected in sterile tubes without anticoagulant and centrifuged at approximately2700‐3000 rpm for 10‐12 min according to the Choukroun protocol. The resulting PRF clotwas compressed into a membrane, cut into small fragments, and homogeneously mixed withthe dentin particles before placement into the extraction sockets.Full‐thickness mucoperiosteal flaps were elevated as required in the Dentin and Dentin +PRF groups, and the graft materials were adapted to ensure close contact with the socketwalls. In the FDBA group, the commercially available allograft was placed with minimal orno flap elevation. In the Control group, the extraction sockets were allowed to healspontaneously through blood clot formation without graft placement or flap surgery. Theflaps were closed using 3‐0 silk sutures. In selected cases in which primary closurecould not be achieved, a free gingival graft was used as a "socket seal." Postoperativecare consisted of a standard antibiotic regimen (amoxicillin/clavulanic acid, 1000 mgtwice daily for 7 days), an NSAID analgesic, and a chlorhexidine/benzydamine mouth rinse.Sutures were removed on postoperative day 10, and patients were followed clinically atmonthly intervals.Four months after grafting, at the time of dental implant placement, cylindricalbone‐core biopsies were obtained from the treated alveolar ridge using a trephine bur.Specimens were fixed in 10% neutral buffered formalin, decalcified in 10% formic acid,and processed for routine histological embedding. Sections (5 µm thick) were stained withhematoxylin and eosin for histomorphometric evaluation of newly formed bone, connectivetissue, vascularization, and residual graft particles.Immunohistochemical staining for bone morphogenetic protein‐2 (BMP‐2) was performedfollowing antigen retrieval. BMP‐2 expression was quantified using a semi‐quantitativeHSCORE method combining staining intensity (0‐3) and the percentage of positively stainedcells. Five randomly selected fields per section were evaluated at ×40 magnificationindependently by two blinded observers.Statistical analyses were performed using IBM SPSS Statistics version 21. The normalityof continuous variables was assessed using the Shapiro‐Wilk test. Normally distributedvariables were analyzed using one‐way ANOVA followed by Bonferroni post hoc comparisons,whereas non‐normally distributed variables were analyzed using the Kruskal‐Wallis testfollowed by Bonferroni‐corrected Mann‐Whitney U tests for pairwise comparisons. A p‐value≤ 0.05 was considered statistically significant.