Guided Bone Regeneration in Canines

Four healthy male canines weighing ~25 kg with a clinically healthy periodontium were used for the present study. The animal selection and management and the surgical procedures were approved by the Ethics Committee on Animal Experimentation (IR.UMSHA.REC.1397.639).
An intramuscular injection of a mixture of Ketamine 10% (Ketamine alfasan, Woerden, Holland, The Netherlands; 10 mg/kg) and Xylazine 2% (5 mg/kg) was used for deep anesthesia. The duration of anesthesia with this method was 1 to 1.5 h. To continue anesthesia, intubation was performed using a combination of oxygen with 1.5% halothane gas (Halothane BP, Nicholas Piramal India Limited, Mumbai, India). Routine dental infiltration anesthesia and lidocaine infiltration (Persocaine-E, Lidocaine HCL 2% + Epinephrine 1/80,000, Daroupakhsh pharmaceutical. Mfg. Co. Tehran, Iran) were used at the surgical sites to control pain and bleeding. Four canines were employed for this study, with a total number of 32 defects. Prior to surgery, oral prophylaxis with 0.2% chlorhexidine was performed. An intra-crevicular incision was made on the buccal aspect of the treated sextants. Following the elevation of the buccal mucoperiosteal flap, four square-shaped dehiscence defects were prepared just below the cemento-enamel junction (CEJ) with dimensions of 5 mm × 5 mm (width × length) on the root surface of the canine, the first and second premolars (distal roots), and the mesial root of the first molars in each side of the mandible (four similar defects in each side of the jaw). The bone defects were prepared using rotating burs under sterile saline irrigation. Root planing was performed using Gracey curettes and chisels, and the cementum and periodontal ligaments were completely removed over the exposed root in the defect area (Figure 3). The CEJ and the most apical portion of the denuded dentin surface were used as histopathological markers to determine the reference points for evaluating bone and periodontal regeneration in the area.
Each defect was washed with normal saline serum and the 32 defects were randomly assigned to four groups: (1) GTR using Botiss Jason^® membrane Botiss Biomaterials GmbH, Zossen Germany (Jason), (2) GTR using Smartbrane membrane, Regedent, Zurich, Switzerland (Smartbrane), (3) The novel 3D-printed membrane, and (4) no membrane (Control) (Figure 3). Each membrane was carefully adapted to the defect to cover 2 mm beyond the defect edges. The placement of the 3D-printed membrane was conducted in a way to have the large pore size (400–500 µm) at the side of the bone tissue and the small pore size (50 to 150 µm) at the side of the soft tissue. This placement was used because the GTR membrane serves to create a physical barrier between the regenerating bone and the surrounding tissue, which helps to prevent the soft tissue from infiltrating the area where the bone is being regenerated and requires a smaller pore size at the side of the soft tissue. Moreover, 400–500 µm is appropriate for the growth of bone tissue.
The flap was repositioned and sutured tightly using 3-0 ePTFE (Osteogenics Biomedical, Inc., Lubbock, TX, USA) at the cemento-enamel junction. The flaps completely covered the membranes in a tension-free closure. The commercial membranes used in this study were porcine pericardium-derived collagen membranes.