On guided bone regeneration using ceramic membranes

Sammanfattning: Regeneration of bone in the oral and maxillofacial region can beachieved with different techniques such as autologous bone grafts,bone substitutes and guided bone regeneration. Guided boneregeneration is defined as creating a space between the bone and itssurrounding tissues, using a barrier that allows new bone to migrateinto the space while preventing other cell types from interfering. Thebarrier material should be biocompatible, have suitable occlusiveproperties and be able to maintain the created space for boneregeneration. A wide range of different materials has been used.The general aim was to evaluate a novel method of guided boneregeneration using designed ceramic space maintaining devices onanimals and humans. An experimental rabbit model was used in studies I, II and III.60 different domes shaped as halfspheres were fixed with titaniumscrews to the skull bone of 30 rabbits. The domes had 5 differentcharacteristics; 1) Dense hydroxyapatite with a moderately roughinner surface (HA rough), 2) Dense hydroxyapatite with a smoothinner surface (HA smooth), 3) Microporous hydroxyapatite with amoderately rough inner surface (HA μ), 4) Dense hydroxyapatite witha moderately rough inner surface and macroscopic holes (HA holes)and 5) Zirconia with a moderately rough inner surface (Zirconia).The domes were left to heal for 12 weeks before the animals wereeuthanized and the results were analysed with histomorphology andmicro-CT. The results revealed that Zirconia with a moderately rough innersurface produced the largest amount of newly formed bone althoughthe results were difficult to interpret as the Zirconia domes weredifficult to X-ray because of the very dense nature of the material.In study IV, 3 patients had bone regeneration treatment with aZirconia barrier. Patient 1 had posterior maxillary bone deficiencyin a transverse direction. Patient 2 had anterior maxillary bonedeficiency in a vertical and transverse direction. Patient 3 hadposterior mandibular bone deficiency in a vertical direction. Basedon individual digital models, Zirconia membranes correspondingto the amount of bone intended to be regenerated were designedand manufactured. The Zirconia membranes, were attached tothe underlying bone with titanium screws and covered with theperiosteum and mucosa. After a mean healing time of 7 months themembranes were removed and dental implants were installed. The results showed new bone regeneration corresponding tothe design of the space maintained. None of the patients had anymajor complications aside from normal postoperative discomfort.According to evaluation with CBCT all patients gained new bone inthe desired and preoperatively planned region.