Tooth Extraction, Alveolar Bone Loss
Conditions
Keywords
Alveolar ridge preservation, Autogenous dentin graft, Platelet-rich fibrin, Extraction socket, Bone regeneration, BMP-2
Brief summary
When a tooth is extracted, the bone around the empty socket naturally shrinks over time, which can make it difficult to place a dental implant later without additional bone-building procedures. This study investigated whether grafting the socket with the patient's own extracted tooth material, processed into a graft (autogenous dentin graft), can help preserve this bone. The study also examined whether adding platelet-rich fibrin (PRF), a concentrate prepared from the patient's own blood that is rich in healing factors, could further improve outcomes. A total of 56 extraction sockets were randomly assigned to one of four treatment approaches: no grafting (natural healing), dentin graft alone, dentin graft combined with PRF, or a freeze-dried bone allograft, which is a commonly used bone substitute for comparison. Four months after treatment, small bone samples were taken from each site at the time of dental implant placement and examined under the microscope to measure how much new bone had formed, along with other markers of healing such as blood vessel formation and a bone-growth protein called BMP-2. The results showed that sockets treated with dentin graft healed at least as well as those treated with the standard bone substitute, and that combining dentin graft with PRF produced the best healing results of all groups tested. These findings suggest that a patient's own extracted tooth, which would otherwise be discarded, may serve as an effective and low-cost graft material for preserving bone after tooth extraction, particularly when combined with PRF.
Detailed description
Following tooth extraction, the alveolar ridge undergoes progressive dimensional changes, primarily due to bundle bone resorption, which may compromise the volume and quality of bone available for future implant placement. Alveolar ridge preservation (ARP) procedures aim to minimize this resorption through the use of various grafting materials. This prospective, randomized, controlled clinical trial was conducted at the Department of Oral and Maxillofacial Surgery, Faculty of Dentistry, Ankara Yıldırım Beyazıt University. Eligible participants were systemically healthy individuals aged ≥18 years (ASA I-II) who required extraction of a radiographically non-infected tooth. Patients with acute infection at the extraction site, advanced systemic disease, use of medications affecting bone metabolism, smoking or alcohol consumption, or anticipated non-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 healing without grafting, n = 13), Dentin (grafted with autogenous dentin particles, n = 14), Dentin + PRF (grafted with autogenous dentin combined with leukocyte- and platelet-rich fibrin, n = 15), and FDBA (grafted with freeze-dried bone allograft, n = 14). All surgical procedures were performed by the same operator to eliminate inter-operator variability. 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 of 80%, and an alpha level of 0.05. The analysis indicated that a minimum of 52 extraction sockets (13 per group) was required. Autogenous dentin grafts were prepared immediately after extraction according to the method described by Binderman et al. Soft-tissue remnants, enamel, and cementum were removed from the extracted teeth using a tungsten carbide bur under water cooling. The cleaned teeth were processed using a Smart Dentin Grinder (KometaBio, Israel) to obtain particulate graft material with a particle size of 300-1200 µm. The particles were subsequently disinfected for 10 min in a solution containing 20% ethanol and 0.5 M NaOH and 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 blood collected in sterile tubes without anticoagulant and centrifuged at approximately 2700-3000 rpm for 10-12 min according to the Choukroun protocol. The resulting PRF clot was compressed into a membrane, cut into small fragments, and homogeneously mixed with the 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 socket walls. In the FDBA group, the commercially available allograft was placed with minimal or no flap elevation. In the Control group, the extraction sockets were allowed to heal spontaneously through blood clot formation without graft placement or flap surgery. The flaps were closed using 3-0 silk sutures. In selected cases in which primary closure could not be achieved, a free gingival graft was used as a "socket seal." Postoperative care consisted of a standard antibiotic regimen (amoxicillin/clavulanic acid, 1000 mg twice 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 at monthly intervals. Four months after grafting, at the time of dental implant placement, cylindrical bone-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 with hematoxylin and eosin for histomorphometric evaluation of newly formed bone, connective tissue, vascularization, and residual graft particles. Immunohistochemical staining for bone morphogenetic protein-2 (BMP-2) was performed following antigen retrieval. BMP-2 expression was quantified using a semi-quantitative HSCORE method combining staining intensity (0-3) and the percentage of positively stained cells. Five randomly selected fields per section were evaluated at ×40 magnification independently by two blinded observers. Statistical analyses were performed using IBM SPSS Statistics version 21. The normality of continuous variables was assessed using the Shapiro-Wilk test. Normally distributed variables were analyzed using one-way ANOVA followed by Bonferroni post hoc comparisons, whereas non-normally distributed variables were analyzed using the Kruskal-Wallis test followed by Bonferroni-corrected Mann-Whitney U tests for pairwise comparisons. A p-value ≤ 0.05 was considered statistically significant.
Interventions
Particulate graft material (300-1200 µm) obtained by processing the patient's own extracted tooth using the Smart Dentin Grinder device (KometaBio, Israel), placed into the extraction socket.
Autogenous dentin particles combined with platelet-rich fibrin, prepared by centrifugation of the patient's own venous blood (2700-3000 rpm, 10-12 minutes), placed into the extraction socket.
Commercial freeze-dried bone allograft placed into the extraction socket as a comparator graft material.
Sponsors
Study design
Masking description
Histological and immunohistochemical evaluations, including HSCORE assessment of BMP-2 expression, were performed independently by two blinded observers who were unaware of the group allocation of each specimen. Surgical treatment allocation was not blinded to the operating surgeon or the patient, as the graft materials used (autogenous dentin, dentin combined with platelet-rich fibrin, freeze-dried bone allograft, or no graft) were visually and procedurally distinguishable.
Intervention model description
A total of 56 extraction sockets were randomly allocated in parallel to one of four independent treatment groups: spontaneous healing (Control), autogenous dentin graft alone (Dentin), autogenous dentin graft combined with platelet-rich fibrin (Dentin + PRF), or freeze-dried bone allograft (FDBA). Each socket received only one treatment throughout the study, with outcomes compared across groups at a single follow-up timepoint four months after grafting, corresponding to the time of dental implant placement.
Eligibility
Inclusion criteria
* Systemically healthy individuals (ASA I-II) * Age 18 years or older * Presence of a tooth requiring extraction, radiographically confirmed to be non-infected
Exclusion criteria
* Presence of acute infection at the extraction site * Advanced systemic disease * Use of medications known to affect bone metabolism * Current smoking or alcohol use * Anticipated non-compliance with scheduled follow-up visits
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Percentage of Newly Formed Bone | 4 months after grafting | Histomorphometric quantification of the percentage of newly formed bone within the grafted extraction socket, assessed on hematoxylin and eosin-stained sections of bone core biopsies obtained at the time of implant placement. |
| Percentage of Connective Tissue Formation | 4 months after grafting | Histomorphometric quantification of the percentage of connective tissue within the bone core biopsy specimens. |
| Vascularization | 4 months after grafting | Histomorphometric assessment of new vessel formation within the bone core biopsy specimens. |
| BMP-2 Immunoexpression (HSCORE) | 4 months after grafting | Semi-quantitative immunohistochemical assessment of bone morphogenetic protein-2 (BMP-2) expression, calculated using the HSCORE method combining staining intensity and percentage of positive cells. |
Countries
Turkey (Türkiye)