The Effect of Different Types of Collagen Membranes on Peri-Implant Dehiscence Defects.

AIM: This experimental study aimed to compare the bone-implant contact (BIC) following guided bone regeneration with 3 bioabsorbable collagen membranes on peri-implant dehiscence defects. METHODS: Forty-eight standard dehiscence defects were created in the sheep iliac bone crest, and dental implants were placed into the defects. With the guided bone regeneration technique, the autogenous graft was placed into the defect and covered with different types of membranes: Geistlich Bio-Gide, Ossix Plus, and Symbios Prehydrated were covered. One group was left without a membrane as the control group (C) by applying only an autogenous graft. After recovery periods of 3 and 6 weeks, the experimental animals were sacrificed. Histologic sections were prepared by a nondecalcified method, and BIC was examined. RESULTS: There was no statistically important difference between groups in the third week ( P >0.05). A statistically significant difference between groups was found in the sixth week ( P <0.01). Bone-implant contact values of the C group were significantly lower than those of the Geistlich Bio-Gide and Ossix Plus groups ( P <0.05). There was no statistically significant difference between control and Symbios Prehydrated groups ( P >0.05). In all sections, osseointegration was observed, with no signs of inflammation, necrosis, or foreign body reaction. CONCLUSION: In our study, it has been concluded that the resorbable collagen membranes used in treating peri-implant dehiscence defects might affect the BIC, and the success varies according to the type of membrane used.

In vivo comparison of customized zirconia barriers in guided bone regeneration: An experimental study.

Objective: This study aims to evaluate the effects of customized zirconia barrier membranes produced for guided bone regeneration (GBR) approaches on bone healing researched with histological and histomorphometric methods. Methods: The digital modeling was used to create zirconia barrier membranes suitable for the defect on the tibia bone. The membranes were designed using a 3D software system and transferred to the CAD/CAM software system in stl. Afterward, zirconia discs (1400 Mpa) (Aconia BSM- D98 × 16, HT+, Germany) were milled and sintered. Titanium mesh, titanium reinforced d-PTFE, and zirconia barrier membranes were used to cover the defects. As a control group, one defect was left empty. 3 and 6 weeks of the healing term, preparates were obtained from each group after animals were sacrificed. New bone formation, amount of the remaining grafts and tissue response parameters were analyzed histomorphometrically and histologically. Results: The highest percentage of newly formed bone in the early period was observed in the titanium mesh membrane group (26.39 ± 5.38); In the late period, this rate was highest in the zirconia group (64.42 ± 9.95). However, no statistically significant difference was found in both periods between the groups. The amount of residual graft progressed at a low level in both periods without any difference in the other groups except the control group. In the 3rd and 6th weeks, the amount of new bone formation was the lowest in the control group. No foreign body reaction or necrosis was observed in any of the defects. Conclusion: With the limitation of the study, it has been concluded that effective results can be obtained with customized zirconia barrier membranes in GBR procedures.

A novel technique of pulmonary artery banding by means of radiofrequency ablation: An experimental study in rabbits.

Background: The aim of this study was to evaluate the efficacy and feasibility of a novel method of narrowing pulmonary arteries with catheter angiography using radiofrequency energy in rabbits. Methods: A total of nine New Zealand white rabbits weighing 3.0 to 4.2 kg each were utilized in this experimental study. After the location of pulmonary artery was confirmed by echocardiography and angiography, radiofrequency energy was applied by starting with 5 W energy for the first time and increasing by 5 W, if there was no rupture to a maximum of 20 W. Multiple applications of radiofrequency energy with different durations were performed at different levels of the pulmonary artery. Eight weeks later, surviving rabbits were sacrificed. The pulmonary arteries were removed for histological investigation. Results: Five rabbits remained alive after the experiment. There was a significant correlation between radiofrequency power and the degree of vessel thickness change in the pulmonary artery. The endothelial integrity of the tunica intima was impaired in all groups and the diameter of vessel was thickened by an average of 3.5 times. Conclusion: The narrowing of the pulmonary artery using radiofrequency energy was successfully performed in a small sample size of experimental animals in this study.