Oral verrucous carcinoma.

Verrucous carcinoma is a well-defined variant of the squamous cell carcinoma. Although it is reported to be rare in the Scandinavian countries, 16 cases have been diagnosed in the Southern part of Norway from 1975 to 1982. The clinical and histological characteristics were investigated. The most common site of occurrence was the mandibular alveolar ridge. The average age was 71 years, and unlike most other series of verrucous carcinoma, there was a female predominance and use of tobacco seemed to be the exception. The patients mainly complained of ill-fitting dentures. Adequate surgical excision appears to be the treatment of choice.

Further studies on tissue ingrowth into intrabony porous ceramic implants.

Porous ceramic Al2O3 implants with pore size of 100-750 micrometers were placed intrabony in the maxillary tuberosity of eight Cercopithecus monkeys. All implants healed primarily. Vital staining of mineralizing tissue was attempted using intravenous injections of tetracycline and calcein. The implants were retrieved after implantation times of 3, 5, 10, 11 and 12 months. Infiltration of fibrous tissue and bone was found in all impants, but the amounts of tissue observed were not significantly greater after the longest implantation times as compared to the 3- and 5-month results.

Porous ceramic implants in the alveolar ridge of humans. A 3 1/2-year follow-up study.

Porous ceramic (Al2O3) material with pore size of 100--750 micrometer was used for alveolar ridge augmentation in five patients. Clinical and radiographic examination at observation times varying from 11 months to 3 1/2 years revealed that seven out of a total number of nine implants were in function, covered by normal soft tissue. All patients were wearing complete dentures over the implant sites. In one of the patients treated with three ceramic pieces placed subperiosteally to restore alveolar height, one of the implants was lost after 3 1/2 years. In another individual, a minor dehiscence was found on examination after 2 1/2 years' implantation time. Interviews revealed that one of the patients had hypoesthesia and paresthesia in the mental nerve area on one side after ridge augmentation, while the remaining four patients had no complaints. All five individuals told of considerable improvement of denture stability after the implantation procedures.

Subperiosteal transmucosal porous ceramic/titanium implants. Clinical experience from three cases.

Porous ceramic (Al2O3) material was used in combination with titanium fixtures as subperiosteal transmucosal implants in three patients at the Department of Oral Surgery and Oral Medicine, Dental Faculty, University of Oslo. Ceramic pieces were furnished with titanium receptacles and matching threaded posts. The implantation approach was based upon two stages, the first for subperiosteal placement of the ceramic onlay segment containing the titanium receptacles, and the second procedure for perforation of the mucosa and insertion of the posts intended for prosthetic use. A healing period of 8 weeks was planned between the two procedures. In one of the patients, however, the implants were removed only a few weeks after placement because of inflammation and soft tissue breakdown over the ceramic material. Reoperation was performed, however, with the same negative results. The other two individuals retained the implants, with uneventful postoperative healing periods. Between 6 and 8 weeks after mucosal perforation and insertion of the titanium posts, however, subjective and objective symptoms of infection were registered in both patients. In addition, one of the cases exhibited dehiscence and exposure of the ceramic. The implants were removed in both individuals.

Tissue reaction to submerged ceramic tooth root implants. An experimental study in monkeys.

Tooth root replica implants made from alumina ceramic material of solid structure coated with a porous layer, were used as dental implants in monkeys. The porous coating was 1/2 mm thick and had pore sizes within 50--200 microns range, with a 30% degrees of porosity. Tne implants were inserted into prepared sockets in the mandible of 5 Cercopithecus monkeys. After submerged implantation periods varying from 5 to 15 weeks, a perforating steel post was introduced through the covering gingiva into the artificial root canal of the implants. The animals were sacrificed after 6 weeks, 2, 3 and 4 months. Three out of the total number of 10 implants were lost. The remaining 7 specimens were retrieved for histologic and microradiographic examination. Fibrous and mineralized tissue ingrowth of the porous layer of the implants was found. No adverse reactions of the adjacent bone were demonstrable. The implants became anchored to the host and no epithelial downgrowth along the ceramic was found.

Experimental subperiosteal implantation of porous Al2O3 ceramic for mandibular ridge augmentation.

Porous Al2O3 ceramic material with pore size of 100-750 micrometers was used for implants placed subperiosteally as alveolar ridge augmentation onlays in six Cercopithecus monkeys. Clinical and radiographic examination during the postoperative period revealed rapid healing and anchorage of the implant in five of the animals. One implant was lost. The implants were retrieved after 4, 10, 11 and 12 months' implantation time. Histologic and microradiographic examination demonstrated fibrous and bone tissue invasion into the pore system at the base of the subperiosteal implant, with good anchorage of the ceramic material to the jaw. Only fibrous tissue was found to project into the ceramic openings on the implant sides facing the periosteum. Labeling of the mineralizing tissue was attempted using intravenously administered tetracycline (Reverin) and calcein (Calcein) at varying intervals prior to sacrifice, but the labeling results were not impressive.

Ultrastructure of tissue in intrabony and subperiosteal porous ceramic implants.

Porous ceramic (Al2O3) implants with pore size of 100--750 micron were placed intrabony in the maxilla and subperiosteally in the mandible of three adult monkeys. After observation periods of 10, 11 and 12 months, the animals were perfused with 1.7% glutaraldehyde and the jaws processed for electron microscopy. Tissue ingrowth into the pores was observed in all the specimens. The implant pores facing the host bone contained bone tissue to a depth of approximately 1 mm, while only unmineralized tissue was found in the implant part adjacent to the periosteum. The unmineralized tissue was of a fibrous nature with collagen fibers arranged in a lamellar fashion. Cells, often with extremely long and slender cellular processes, were seen between the lamellae. The cells had the cytoplasmic features typical of protein-producing cells. The mineralized tissue exhibited ordinary bone tissue structure with plate-like crystallites in a collagenous matrix. Some lacunae and canaliculi with osteocytes were observed, though they were scarce.

Rebuilding of deficient edentulous alveolar ridge with porous ceramic implants.

Porous ceramic (Al2O3) implants with a pore size of 100--750 mum were used in the surgical treatment of four patients at the Department of Oral Surgery and Oral Medicine, Dental Faculty, University of Oslo. In two of the cases, ceramic implants were placed in small surgical defects in the edentulous maxillary alveolar ridge, while two patients were treated with mandibular ridge augmentation. All four individuals healed uneventfully, and the implants were firm and immovable 3 weeks postoperatively. No adverse tissue reactions were observed. Dentures were inserted over the implants 8 days to 6 weeks after implantation. In one of the cases, reoperation was performed because of 2 X 2 mm zone of exposure of the ceramic 4 weeks after denture insertion. Examination after observation times up to 15 months revealed clinically normal soft tissue over the implants. There were no complaints about wearing of the dentures. Radiographs at varying intervals after implantation did not disclose any pathologic changes or signs of resorption of bone adjacent to the ceramic implants.

Oral antrostomy.

Removal of localized polypous maxillary sinus membrane is, in our opinion, occasionally indicated in conjunction with surgical closure of oroantral communication. An alternative to nasal antrostomy is presented in this paper. Packing the maxillary sinus with gauze to prevent the collection of blood and to secure drainage is achieved by carrying the end of the gauze strip subperiosteally and through the vertical incision in the anterior part of the vestibule. This technique was applied in the treatment of the 12 patients included in this study. All of these were treated as outpatients. At follow-up visits after 2 months to 1 years, all patients were found to be without symptoms or complaints.