Preprosthetic Stage Dental Implant Failure

Since the introduction of the concept of osseointegration, the success rate of dental implant has increased dramatically. So, the uses of dental implant in the treatment of partially or fully edentulous patients have played an important role in dental rehabilitation. Regardless of high success rate of dental implant, some amounts of fixtures cannot help failing. We can classify dental implant failure according to timing, causative factor, etc. This study is focused on dental implant fixture failure, occurring during preprosthetic stage. There are various reasons that cause implant failure on this periods, such as improper patient selection, poor bone quality, and periimplantitis, etc. We investigate the survival rate of 1058 fixtures, which installed in 306 patients in our clinic from January 1997 to December 1999, according to type, sex, location, fixture length and width, using Kaplan-Meier product-limit method and to compare each other with log-rank test. Overall survival rate was 96.80%, and 33 implants failed over the preprosthetic stage. Our survey data identified posterior location of mandible as being associated with implant failure(P<0.05).

Consideration of Transverse Movement of Posterior Maxilla in Orthognathic Surgery of Facial Asymmetry: Case Reports

When we establish treatment planning of facial asymmetry, we must predict each asymmetrical element that will be changed upon coronal, axial, sagittal plane. At the visual point, prediction of the change of coronal plane is most important. It is important difference between Rt. and Lt. mandibular angle belonging to posterior coronal plane, as well as anterior coronal plane, such as upper and lower incisor, or midline of chin point. Several methods for control bulk of mandibular angle are additional angle shaving after osteotomy, grinding contact area between proximal and distal segment for decrease the volume, or bone graft for increase the volume. But, at the point of bimaxillary surgery, transverse position of posterior maxilla is an important factor for control it. So, we would report transverse movement of posterior maxilla for decrease asymmetry on the posterior coronal plane of face, that is, asymmetry of mandibular angular portion.