Restoration of irradiated patients using osseointegrated implants: current perspectives.

STATEMENT OF PROBLEM: The success rates of osseointegrated implants used to restore patients who were irradiated for head and neck tumors are influenced by radiation-induced changes in the hard and soft tissues. PURPOSE: This article examined, by review of the literature, current perspectives on the restoration of irradiated patients using osseointegrated implants. RESULTS: In published reports that investigated both intraoral and extraoral applications, irradiation decreased implant success rates and the amount of reduction was dependent on the location within the craniofacial skeleton. The limited number of implants and patients in these studies precludes definitive conclusions regarding the efficacy of placing implants into irradiated tissues. The implants placed into the irradiated anterior mandible have demonstrated an acceptable implant success rate of 94% to 100% with a minimal risk of osteoradionecrosis. The efficacy of implants in the posterior mandible has not been examined. Implant success rates ranged from 69% to 95% in the irradiated maxilla for intraoral applications. Extraoral applications demonstrated excellent implant success rates in the temporal bone (91% to 100%). The rates in the anterior nasal floor have varied from 50% to 100%. The implant success rates in the frontal bone decreased as the length of the studies increased (96% to 33%). The long-term efficacy of implants in the irradiated frontal bone is poor.

Osseointegrated implants and orbital defects: U.C.L.A. experience.

PURPOSE: A clinical study of 23 craniofacial implants placed in 8 irradiated and nonirradiated orbital detects was conducted over a 7-year period. MATERIAL AND METHODS: Implant-retained orbital prostheses were fabricated, implant success rate was determined, and the soft tissue responses were recorded at 6-month intervals. As a result of patient death, no data were gathered on three implants. A five-point scale was used to record the health of the peri-implant soft tissues and the patients were followed from 9 to 72 months. The unit of measure was a visit/site that was assigned for each instance an implant site was evaluated. Evaluations were conducted at 6-month intervals, and for the study period, there were 80 visit/sites. RESULTS: The study revealed that 42.5% (34/80) of the visit/sites demonstrated an absence of inflammation; 23.7% (19/80) of visit/sites demonstrated slight redness; 13.8% (11/80) demonstrated peri-implant red and moist tissues; 6.2% (5/80) demonstrated granulation tissue associated with the implants; and 13.8% (11/80) infection of the peri-implant soft tissues was noted. Implant success rate was 35% (7/20); implant success rate in the nonradiated patients was 37.5% (3/8) and the success rate for radiated patients was 33.3% (4/12). Implants placed in the orbital region demonstrated a high failure rate. Most implant failures occurred late as opposed to early in the study period. CONCLUSION: Orbital implants should be placed in patients who understand that long-term success rates may be low and require meticulous hygiene maintenance.

Nasal defects and osseointegrated implants: UCLA experience.

A clinical study of 23 craniofacial implants placed in 11 nasal defects was conducted over a 7-year period. Implant-retained nasal prostheses were fabricated, implant success rate was determined, and the soft tissue responses were recorded at 6-month intervals. No data were gathered on two implants because of patient death. The implant success rate was 71.4% (15/21) but varied significantly by anatomic site. The implant success rate in the glabella was 0% (0/4), whereas the success rate in the anterior nasal floor was 88.1% (15/17). All implant failures occurred within the first year of loading. A five-point scale was used to record the health of the peri-implant soft tissues, and the patients were followed up from 6 to 74 months. The unit of measure was a visit/site, and a unit was assigned for each instance an implant site was evaluated. Evaluations were conducted at 6-month intervals for a total of 76 visit/sites for the study period. The results revealed that 85.5% (65/76) of the visit/sites demonstrated an absence of inflammation; 10.5% (8/76) of the visit/sites demonstrated slight redness; 1.3% (1/76) demonstrated peri-implant red and moist tissues; 2.6% (2/76) demonstrated granulation tissue associated with the implants; and 0% (0/76) demonstrated infection of the peri-implant soft tissues. Severe soft tissue reactions around implants placed in the anterior nasal floor are rare.

Auricular prostheses and osseointegrated implants: UCLA experience.

A clinical study of 40 craniofacial implants placed in 13 auricular defects was conducted over a 6-year period. Implant-retained prostheses were fabricated, the implant success rate was determined, and the soft tissue responses were recorded at regular intervals. All of the implants became osseointegrated and none demonstrated failure during the study period. A five-point scale was used to record the health of the peri-implant soft tissues and the patients were followed up for up to 69 months. The results were as follows: 55.1% of the visit/sites demonstrated an absence of inflammation; 32.3% of the visit/sites demonstrated slight redness; 4.7% demonstrated red and moist peri-implant tissues; 5.5% demonstrated granulation tissue associated with the implants; and in 2.4% of the implants, infection of the peri-implant soft tissues was noted. Good patient hygiene compliance combined with thin and immobile peri-implant soft tissues resulted in minimal soft tissue complications.

Surgical considerations for endosseous implants in the craniofacial region: a 3-year report.

From 1987 to 1990, 28 patients were treated with titanium implants (Brånemark flange fixtures) in the craniofacial area for the support of craniofacial prosthesis or anchorage of bone-conduction hearing aids in the Orofacial Implant Center at the University of California, Los Angeles (UCLA). A total of 88 implants were placed, of which 22 were placed in previously irradiated areas. Twenty-three of the implants were placed in the orbital area, 37 in the mastoid area, 20 in the nasal area, and eight in various other craniofacial regions. Seven implants were lost in four different patients. The proper location and positioning of implants in specific areas of the craniofacial regions, as well as soft-tissue complications and management, are discussed.

Maxillary sinus augmentation: histomorphometric analysis of graft materials for maxillary sinus floor augmentation.

This study used histomorphometric analysis to quantitate the bone composition of four different sinus grafting materials biopsied at the time of implant installation. The study consisted of five patients in whom eight bone biopsies were obtained from seven grafted sites. The grafting materials consisted of hydroxylapatite (HA) granules mixed with cortical chin bone, HA mixed with demineralized bone powder, HA alone, and cortical chin bone alone. Histomorphometry was performed using backscattered scanning electron microscopy images and a computerized image analysis system. The biopsy cores yielded 46 sections from which a total of 255 fields, measuring 2.0 mm x 2.0 mm each, were imaged and analyzed. The biopsy cores contained 44.4% bone after grafting with HA granules and chin bone, 59.4% bone after grafting with chin bone alone, 20.3% bone after grafting with HA granules alone, and 4.6% bone after grafting with HA granules and demineralized bone powder. The small number of biopsies did not permit analysis of statistical significance. However, this study demonstrated the feasibility of correlating mineralized tissue composition of different sinus grafting materials with clinical outcome after dental implant installation.

The association between the failure of dental implants and cigarette smoking.

This paper reviews the outcome of 2,194 Brånemark implants placed in 540 patients by one of the authors over a 6-year period. The overall failure rate of 5.92% is consistent with other studies; however, when patients were subdivided into smokers and nonsmokers, it was found that a significantly greater percentage of failures occurred in smokers (11.28%) than in nonsmokers (4.76%) (P < .001). These differences were significant for all areas except the posterior mandible. While failure rates decreased with increasing implant length, failure rates for each implant length were consistently higher in smokers than in nonsmokers. The possible mechanisms of failure in smokers are discussed, and a protocol for cessation of smoking around the time of surgery is proposed.

Histomorphometry of bone apposition around three types of endosseous dental implants.

Three different types of commercially available dental implants (Nobelpharma, IMZ, and Integral) were implanted in the edentulous mandibles of seven adult mongrel dogs. Twenty-one implants were harvested with block sections after 12 weeks and embedded in polymethyl methacrylate resin. Undecalcified sections were prepared with the sectioning-grinding technique. The percentage of bone contacting the implant surface was measured with a self-designed histomorphometry method using a millimeter grid in a stereomicroscope. The results demonstrated a significantly higher percentage of bone along the hydroxyapatite-coated implant than that seen with the titanium-surfaced implant types.

Soft-tissue modifications of surgical techniques for placement and uncovering of osseointegrated implants.

The recommended modifications of soft-tissue management for two-stage implant surgeries have resulted in improved access for implant placement, accommodation of surgical stents, less formation of cicatrix in the vestibules, better control of flap extensions resulting in improved esthetics, and improved tissue quality for long-term peri-implant maintenance and success. The implication of periodontal guidelines to the uncovering procedure of dental implants result in decreased thickness of peri-implant tissues and less pocket formation around the transmucosal sleeves. These modifications contribute significantly to the long-term periodontal maintenance of peri-implant tissues.

Chronic osteomyelitis of mandible caused by penicillin-resistant Bacteroides ruminicola. Report of a case.

Osteomyelitis of the jaws caused by a Bacteroides species is uncommon. A case of osteomyelitis of the mandible caused by penicillin-resistant Bacteroides ruminicola is reported. The diagnosis was confirmed by isolation of the organism and bone scan (99mTc medronate disodium) of the mandible. Clindamycin and hyperbaric oxygen therapy resolved the infection.

Hyperventilation syndrome: report of case.

Hyperventilation is a common response to anxiety or threatening situations. In certain individuals, it is a mechanism for producing alarming physiologic and metabolic changes. The changes as well as the causes and treatment have been described.