William R. Laney

Tissue Integration in Oral, Orthopedic and Maxillofacial Reconstruction

This work contains papers from an international congress on tissue integration in oral, orthopaedic and maxillofacial reconstruction, held at the Mayo Clinic in 1990. It includes 50 presentations along with the consensus reports from four panels on tissue-integrated prostheses.

Dental Implants: Tissue-Integrated Prosthesis Utilizing the Osseointegration Concept

As an alternative to conventional removable dentures, osseointegrated dental implants can now be used in carefully selected edentulous or partially edentulous patients. The implant consists of a dental prosthesis and an anchorage unit made up of screw-connected components. The implantation procedure is performed in two phases: fixture installation and fixture uncovering and abutment connection. After completion of these surgical procedures, the dental prosthesis is fabricated and inserted. Follow-up examinations are scheduled at 1, 3, and 6 months and then annually thereafter. During a 2-year period at the Mayo Clinic, 358 osseointegrated dental fixtures were implanted in 70 patients. The overall success rate in this consecutive series of patients was 98%, and the associated complications were minimal and easily resolved.

Tissue-Integrated Dental Prostheses: The First 78 Months of Experience at the Mayo Clinic

During a 78-month period at the Mayo Clinic, 1,778 Brånemark endosseous dental implants were placed in the edentulous or partially edentulous jaws of 353 consecutive patients who ranged in age from 8 to 82 years. The largest treatment category involved edentulous mandibles, which accounted for 53% of the total restorations. Approximately 76% of the threaded cylindrical implants supported 312 oral prostheses at the end of the study period. The implant survival rate was 97.8% in the mandible and 88.8% in the maxilla. Complications associated with this treatment included loss of implant anchorage in bone, soft tissue problems, and mechanical difficulties related to design and function of the prostheses. All complications were managed without loss of continuous function of the prostheses, except in four patients who resumed wearing a conventional removable maxillary complete denture. This experience demonstrates that Brånemark endosseous dental implants are predictable and can provide lasting integration under function when placed and loaded in accordance with the recommended protocol.

Grafted skin as an oral prosthesis-bearing tissue

Abstract Although the transplanting of free split-thickness grafts of skin into the oral cavity is not a new procedure, the use of skin as a supporting tissue for oral prostheses has been studied only a short time. Coordinated surgical and prosthodontic treatment has been provided for 34 selected edentulous patients, enabling them to have a more extensive and effective mandibular denture foundation, the buccal and labial surfaces of which are lined with skin.

Fatigue strength of cantilevered metal frameworks for tissue-integrated prostheses

The design of the metal alloy framework in cantilevered sections of fixed tissue-integrated prostheses, is critical. Several cross-sectional designs have been advocated, including the popular L-shaped beam, which permits the economical use of space for tooth placement. The fatigue strengths of 15 L-shaped cantilevered framework sections of the same metal alloy were tested. The castings were divided into three groups of five according to vertical wall heights of 4, 5, and 6 mm. Fatigue durability of each sample was determined by counting the number of cycles of vertical forces required to induce catastrophic failure. Statistical analysis revealed significant differences between all three groups in the cycles counted at failure (p less than 0.0019). Fatigue strengths improved significantly with increasing vertical wall height of the L-shaped cantilevered frameworks. In addition, beam flexure was shown to be indirectly proportional to fatigue strength. Theoretical beam deflection was calculated and shown to correlate with the actual beam deflection during the testing. Theoretical calculations in static bending specific for a cross-sectional design may aid in the predictability of fatigue strength.

Prosthetic Rehabilitation After Cancer Resection in the Head and Neck

Because of the potential physiologic, cosmetic, and psychologic deficiencies that can be created by necessary treatment for cancer, the cure in many respects can be as frustrating as the disease. The rehabilitation should be considered before creation of the defect, so that the patient and the prosthodontist will be well aware of the rehabilitative needs and limitations in the particular case.

The use of panoramic radiography in the medical center

Abstract There are innumerable indications and applications for the panoramic radiographic examination of maxillomandibular structure and teeth. This procedure can be used in diagnosis, treatment planning, treatment, and follow-up service. In the medical center, the dentist should make it known that panoramic equipment is available if it is not located within the general radiologic facility. The otolaryngologist, the plastic surgeon, and the head and neck surgeon, especially, will have occasion to use this radiographic technique to advantage and should be aware of its possible applications.

Education in maxillofacial prosthetics

I n response to a challenge by the President of the Academy of Maxillofacial Prosthetics, I. Kenneth Adisman, in 1962, a survey was begun to determine the educational status of maxillofacial prosthetics. In September 1966, the report of the Educational Survey Committee of the American Academy of Maxillofacial Prosthetics was published.’ The report proposed that such a survey would be worthwhile because (1) it could reveal the current trends of postdoctoral teaching and curricula, (2) it could suggest aspects of current postdoctoral teaching that need to be strengthened, and (3) the data collected could be a source of information for those seeking further educational opportunities in maxillofacial prosthetics. A summary of survey findings suggested that although progress had been made in developing clinical techniques and materials, significant deficiencies were evident in existing maxillofacial teaching programs. Among the relevant shortcomings were inadequate physical facilities, too few qualified teaching staff personnel, and lack of time in the curricula. The conclusion was that if the quality of teaching staffs and maxillofacial prosthetic education was to advance, those in charge of existing programs must strive for improvement, recognition, and accreditation of the programs. It is appropriate that a decade later the current state of advanced maxillofacial prosthetic education be considered and present trends and means for further advancement be identified.

Limitation of clinical practice to prosthodontics

Limitation of practice implies specialization and the delivery of services by a specialist who has been recognized for his expertise through formal advanced education, experience, and/or examination. Prosthodontists in limited practice are currently influenced by problems related to patient referrals, third-party payment for services, and competence certification. Perhaps the most significant problem in prosthodontics today is the need to succinctly define the parameters of prosthodontic practice in order to provide guidelines for assuring that such practices are limited to the defined specialty.