Histological Analysis of Osteogenic Potential of Biphasic Calcium Phosphate in Alveolar Ridge Augmentation

The study was designed as a randomized controlled clinical trial. To participate in the study, patients requires to have at least one tooth predisposed to extraction and to have a dental implant placed after completion of the healing period. The indications for tooth extraction are: chronic periapical process, chronic periodontal disease, or fracture of the vertical bone. The inclusion criteria are: age between 18 and 60 years, intact physical and mental health, patient must understand the study protocol, patient must sign an informed consent. Patients will be excluded from the study if they had at least one of the absolute contraindications to implant prosthetic therapy described by Wang and Hwang. Other exclusion criteria included the following systemic diseases: uncontrolled diabetes, osteoporosis and osteopenia, and vitamin D deficiency, bisphosphonate therapy, glucocorticoid therapy, hypothyroidism, uncontrolled cardiovascular disease (hypertension, coronary artery disease, congestive heart failure), and the following local factors: use of tobacco products (up to 10 cigarettes per day) and poor oral hygiene. Pregnant and lactating women will not included in the study.

In addition to the general health criteria mentioned above, the patient has to meet at least one intraoral criterion, namely the presence of a buccal bone defect such as fenestration or dehiscence. Patients who met the inclusion criteria and were willing to participate, are randomly assigned via a web interface (https://www.randomizer.org/).

Participants and materials Participants will be recruited from the oral surgery office. A total of 36 healthy patients will be included in the study. In analyzing the validity of the test, the approach of equivalence of the tested methods and noninferiority of the tested method compared with the existing method was used. With a significance level α of 0.05, a test power of 80%, an expected standard deviation of the predicted result of 10, and an equivalence limit of d = 10, it was necessary to include at least 36 subjects in the study, 18 subjects per group.

A total of 18 patients in the test group will receive I-BCP (Maxresorb® inject, Botiss GmbH, Berlin, Germany). This biomaterial is an alloplastic bone substitute material in the form of a paste that is placed into the defect with a plastic syringe. The material consists of an aqueous gel containing granules of biphasic calcium phosphate in the composition of 60% HA and 40% β-TCP (particle size between 15-50 nm). Patients in the control group will receive BX (cerabone®, Botiss GmbH, Berlin, Germany). The material is completely anorganic and consists of 100% HA. For this study, the material will be used in granular form (the size of the granules is between 0.5 and 1 mm), mixed with physiological solution prior to placement into the defect.

First surgical phase and healing period Before the procedure, the patient will be administered a 3% chlorhexidine solution to rinse the oral cavity for one minute. Local anesthesia (2% Lidocaine®, Belupo, Koprivnica, Croatia) will be then administered and the surgical field will be covered with sterile drapes. A full-thickness mucoperiosteal flap will be elevated at the extraction site. To perform the tooth extraction atraumatically, the roots of the multirooted teeth will be separated with a drill before extraction. The extraction will be performed with atraumatic instruments, with as little trauma to the alveolus as possible. The alveolus is then carefully examined and curetted to remove granulations and stimulate fresh bleeding in the alveoli. The alveolus will be filled to the edge with I-BCP in the test group and BX in the control group. In the end bone grafting biomaterial is covered with a resorbable native collagen membrane obtained from porcine pericardium (Jason® membrane, Botiss GmbH, Berlin, Germany) in both groups. The mucoperiosteal flap will be then adjusted and closed so that the collagen membrane was completely covered with soft tissue (5.0 monofilament). The patient will be then prescribed an analgesic (400 mg ibuprofen) and instructed to take antibiotics (amoxicillin with clavulanic acid or clindamycin) for the next 7 days. On the 10th day after surgery, the sutures are removed.