On guided bone regeneration using ceramic membranes

Abstract: Regeneration of bone in the oral and maxillofacial region can be achieved with different techniques such as autologous bone grafts, bone substitutes and guided bone regeneration. Guided bone regeneration is defined as creating a space between the bone and its surrounding tissues, using a barrier that allows new bone to migrate into the space while preventing other cell types from interfering. The barrier material should be biocompatible, have suitable occlusive properties and be able to maintain the created space for bone regeneration. A wide range of different materials has been used. The general aim was to evaluate a novel method of guided bone regeneration using designed ceramic space maintaining devices on animals and humans. An experimental rabbit model was used in studies I, II and III. 60 different domes shaped as halfspheres were fixed with titanium screws to the skull bone of 30 rabbits. The domes had 5 different characteristics; 1) Dense hydroxyapatite with a moderately rough inner surface (HA rough), 2) Dense hydroxyapatite with a smooth inner surface (HA smooth), 3) Microporous hydroxyapatite with a moderately rough inner surface (HA μ), 4) Dense hydroxyapatite with a 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 were euthanized and the results were analysed with histomorphology and micro-CT. The results revealed that Zirconia with a moderately rough inner surface produced the largest amount of newly formed bone although the results were difficult to interpret as the Zirconia domes were difficult to X-ray because of the very dense nature of the material. In study IV, 3 patients had bone regeneration treatment with a Zirconia barrier. Patient 1 had posterior maxillary bone deficiency in a transverse direction. Patient 2 had anterior maxillary bone deficiency in a vertical and transverse direction. Patient 3 had posterior mandibular bone deficiency in a vertical direction. Based on individual digital models, Zirconia membranes corresponding to the amount of bone intended to be regenerated were designed and manufactured. The Zirconia membranes, were attached to the underlying bone with titanium screws and covered with the periosteum and mucosa. After a mean healing time of 7 months the membranes were removed and dental implants were installed. The results showed new bone regeneration corresponding to the design of the space maintained. None of the patients had any major complications aside from normal postoperative discomfort. According to evaluation with CBCT all patients gained new bone in the desired and preoperatively planned region.