Volume 75 Number 3 Reviews and abstracts 345 staining, silver nitrate radiography, and histology, revealed alterations in the presence, form, location, and relationship of the individual bones. Alterations were located within the body of the sphenoid bone which led to a reduced cranial floor angle and a more vertical clivus. In anencephaly, the bones derived from the chondrocranium were not as severely affected morphologically as those derived from the neurocranium. In the larger dorsal cranial defects the interparietal portions of the occipital bone were relocated an- teriorly to approximate the frontal bone. The occipital components were rotated an- terolaterally and inferiorly with lack of fusion of the chondrocranium posterior to the foramen magnum. In general, the facial bones were severely affected in morphology, size, and spatial and angular measurements. The manner in which these were altered suggests that their morphogenesis is an adaptation to the primary defect of the neuro cranium. Mandibular Advancement Surgery: A Serial Cephalometric Radiograph Study Enrique Reyes-Retana Department of Orthodontics, University of Washington, Seattle, Wash. Serial cephalometric radiographs of eighteen patients at least 10 months after mandibular advancement surgery were examined prior to surgery, 1 to 15 days after surgery, 1 to 3 months after surgery, 4 to 8 months after surgery, and more than 10 months after surgery. Changes in the position of pogonion, lower incisor, soft-tissue pogonion, and lower lip were measured. The greatest amount of skeletal relapse occurred during the first 6 weeks following surgery. The use of an extraoral appliance exerting a superoanterior force against the mandibular symphsis may minimize the tendency for this relapse. Presurgical orthodontic preparation minimizes maxillary incisor retraction and maximizes mandibular incisor retraction. The orthodontic preparation also allows for overcorrection of the mandibular advancement. The tendency for posterior relapse proved to be significantly less in patients with lower mandibular plane angles. Great differences of lower lip response were found. Bone Dynamics Associated With the Controlled Loading of Bioglass-Coated Aluminum Oxide Endosteal Implants John I?. Smith Department of Orthodontics, University of Washington, Seattle, Wash. Aluminum oxide implants coated with bioglass were placed bilaterally in the mandibular first molar region of three male Macaca muluttu monkeys. A lingual arch appliance with continuous lingual force was directed to the endosteal implants. Fusion of the implants to the surrounding bone was achieved in five of the six implants and remained intact throughout loading periods of 2, 5, and 9 weeks in five of the six implants using 425 to 925 Gm. forces. The implant-bone union offered a barrier to downward migration of epithelium and inflammation.

Bone dynamics associated with the controlled loading of bioglass-coated aluminum oxide endosteal implants

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Page 1: Bone dynamics associated with the controlled loading of bioglass-coated aluminum oxide endosteal implants

Volume 75 Number 3 Reviews and abstracts 345

staining, silver nitrate radiography, and histology, revealed alterations in the presence, form, location, and relationship of the individual bones. Alterations were located within the body of the sphenoid bone which led to a reduced cranial floor angle and a more vertical clivus. In anencephaly, the bones derived from the chondrocranium were not as severely affected morphologically as those derived from the neurocranium. In the larger dorsal cranial defects the interparietal portions of the occipital bone were relocated an- teriorly to approximate the frontal bone. The occipital components were rotated an- terolaterally and inferiorly with lack of fusion of the chondrocranium posterior to the foramen magnum. In general, the facial bones were severely affected in morphology, size, and spatial and angular measurements. The manner in which these were altered suggests that their morphogenesis is an adaptation to the primary defect of the neuro cranium.

Mandibular Advancement Surgery: A Serial Cephalometric Radiograph Study Enrique Reyes-Retana Department of Orthodontics, University of Washington, Seattle, Wash.

Serial cephalometric radiographs of eighteen patients at least 10 months after mandibular advancement surgery were examined prior to surgery, 1 to 15 days after surgery, 1 to 3 months after surgery, 4 to 8 months after surgery, and more than 10 months after surgery. Changes in the position of pogonion, lower incisor, soft-tissue pogonion, and lower lip were measured. The greatest amount of skeletal relapse occurred during the first 6 weeks following surgery. The use of an extraoral appliance exerting a superoanterior force against the mandibular symphsis may minimize the tendency for this relapse. Presurgical orthodontic preparation minimizes maxillary incisor retraction and maximizes mandibular incisor retraction. The orthodontic preparation also allows for overcorrection of the mandibular advancement. The tendency for posterior relapse proved to be significantly less in patients with lower mandibular plane angles. Great differences of lower lip response were found.

Bone Dynamics Associated With the Controlled Loading of Bioglass-Coated Aluminum Oxide Endosteal Implants John I?. Smith Department of Orthodontics, University of Washington, Seattle, Wash.

Aluminum oxide implants coated with bioglass were placed bilaterally in the mandibular first molar region of three male Macaca muluttu monkeys. A lingual arch appliance with continuous lingual force was directed to the endosteal implants. Fusion of the implants to the surrounding bone was achieved in five of the six implants and remained intact throughout loading periods of 2, 5, and 9 weeks in five of the six implants using 425 to 925 Gm. forces. The implant-bone union offered a barrier to downward migration of epithelium and inflammation.