3d Measurement Of Bone Available For Maxillofacial Implants

Facial defects always result from the combined treatment of surgery and radiation for the malignant tumor. Therefore, the reconstruction of defect area becomes important, which can be achieved by making facial prosthesis. Good retention is the necessary condition for prosthesis to exercise functionally in a long time. Since the introduction of dental implants as facial prosthesis retention, cranio-maxillofacial reconstruction has had a full new meaning, which can perfectly solve the retention problem and improve the quality of life significantly. In order to perform the implant surgery safely and effectively, the anatomy of cranio-maxillofacial region had to be learned carefully because of the complexity of craniofacial bone anatomy. However, applied anatomy of maxillofacial implants region was not much both native and aboard. Measurement based on 3D reconstruction images from CT is the best way to study the cranio-maxillofacial bone anatomy.In order to provide anatomy data for the cranio-maxillofacial implant surgery and reduce the failure rate of the implant surgery, the three dimensional quantitative measurement of the cranio-maxillofacial region(anterior nasal floor, temporal bone, and orbital rim)were performed in CT reconstruction images of 100 cases. Air room in temporal region was initiatively surveyed, which could guide the implants surgery. The results of the study are as follows:1.1 The minimum distance between the root tips of central incisor and the anterior nasal floor was 13.03 in male and 11.06 in female. The minimum distance between the anterior nasal floor and the root tips of lateral incisor was 15.95mm in male and 13.04mm in female. the minimum thickness of palatine process 6mm inferior to piriform aperture was 9.96mm, The lateral incisor region is an optimal one for nasal implants 4~8mm in length. The inclined direction can either be forward or backward.1.2 The minimum thickness of alveolus 6mm inferior to piriform aperture was 11.22mm, when the vertical bone depth is no enough, horizontal placement of the implants in the inferior region of piriform should be considered. 4~8mm implants is suitable in this region.1.3 The glabella region is not a optimal but an alternative option for nasal implants.2.1 In the temporal bone, the area of 11:00-12:00(right ear) and 16-25mm from the center of the external auditory canal is lack of air room. 12:00 area has insufficient bone depth while 11:00 has relatively sufficient bone depth. 4-5mm implant is suitable in 11:00 region.2.2 In the temporal bone, the area of 10:00and 19-25mm from the center of the external auditory canal is rich in air rooms(85%-98%). The area is suitable for 5-7mm implants with a average bone depth ranging from 6.13 to 8.72., while 16mm from the center is not a suitable place for implants with a average bone depth of 4.36mm. 2.3 In the temporal bone, the area of 9:00 and 19-25mm from the center of the external auditory canal is rich in air room. The area is suitable for 4-5mm implants with a average bone depth ranging from 5.24 to 6.26. In the area of 8:00 and 25mm from the center of the external auditory canal is suitable for implant placement. The 7:00 area is an alternative region for auricular implants.3.1 In the orbital region, except for the 6:00 area, in the rest of 6:00-9:00 region of the orbit(right side), the depth and width of bone are sufficient for 6-7mm implants. The angle of orbital rim of this area is obtuse angle. So the direction of the implants should be perpendicular to the bone surface.3.2 In the orbital region, in the area of 9:00-12:00 region, bone depth is enough while bone width is not. The angle of the orbital rim in this area is acute. Implant direction should be back forward instead of vertical to the surface in case that the implants come out of the facial surface.