The cancer-promoting effect of N-nitrosonornicotine used in combination with a subcarcinogenic dose of 4-nitroquinoline-N-oxide and 7,12-dimethylbenz (A) anthracene.

PURPOSE: This study was conducted to determine the possible carcinogenic role of N-Nitrosonornicotine (NNN) when combined with subcarcinogenic doses of strong carcinogens dimethylbenz (a) anthracene (DMBA) and 4-nitroquinoline-N-oxide (4NQO) in the hamster cheek pouch. MATERIALS AND METHODS: Eighty-five Syrian golden hamsters were randomly divided into three main groups. Group A contained 35 animals, 20 of which were treated with 0.1% DMBA followed by 4% NNN (A-I), 5 with 0.1% DMBA (A-II), 5 with 4% NNN (A-III), and 5 with mineral oil alone (A-IV). Group B contained 23 animals, 13 of which were treated with 0.5% 4NQO followed by 4% NNN (B-I), 5 with 0.5% 4NQO (B-II), and 5 animals with propyleneglycol alone (B-III). Group C contained 27 animals, 14 of which were treated with 0.1% DMBA followed by 4% NNN and 0.5% 4NQC (C-I), and 13 with 0.1% DMBA followed by 0.5% 4NQO (C-II). All animals were treated three times per week for 16 weeks. A total of 7 animals died during this period. RESULTS: Squamous cell carcinoma (SCCA) developed in eight animals (67%) in the group treated with all three chemicals (C-I), in four animals (33%) treated with DMBA and 4NQO (C-II), in two animals (15%) treated with 4NQO and NNN (B-I), and in two animals (11%) treated with DMBA and NNN (A-I). The difference between the number of animals that developed carcinoma in group C-I and those in groups A-I and B-I was statistically significant (P < .05) and this difference reached a significant value when group C-I and C-II were compared (P < or = .1). There was a direct relationship between the number of tumors produced in animals and the number of different chemicals applied. CONCLUSION: The results of this study indicate that NNN, when combined with subcarcinogenic doses of other strong carcinogens, is a promoter in the development of squamous cell carcinoma and that 4NQO in 0.5% concentration is a stronger carcinogen than 0.1% DMBA.

Orofacial lipomas diagnosed by CT and MRI.

Oral lipomas buried deep in soft tissues can be difficult to diagnose clinically. Computed tomography or magnetic resonance imaging can aid the diagnosis of this rare oral lipoma.

Antimicrobial prophylaxis in oral surgery.

Administration of antimicrobial prophylaxis is advocated in procedures with a high risk of surgical wound infection. Recent advances in knowledge in this area include the broader recognition of risk factors that better predict the expected incidence of postoperative surgical wound infection than does the traditional wound classification system. In oral surgery, guidelines for antimicrobial prophylaxis based on established principles exist in the literature, and antimicrobial prophylaxis has been demonstrated to be effective in preventing postoperative surgical wound infection. However, surveys suggest that fundamental principles are often ignored, and antibiotics are often initiated at an inappropriate time and are continued beyond the time required to be influential on reduction of infection rates.

Solitary neurofibroma of the mandible and infratemporal fossa in a young child. Report of a case.

The first case of a rare and unusual solitary neurofibroma of the mandible that caused bony erosion and extension into the adjacent soft tissues of the infratemporal fossa is presented. The clinical, radiographic, and histopathologic features of the neurofibroma are reviewed. The diagnostic procedures and the surgical treatment of this tumor in a young child are discussed.

An exaggerated response of intra-oral pyogenic granuloma during puberty.

Intra-oral pyogenic granulomas have been associated with pregnancy. The exaggerated response of these tumors has been related to the hormonal changes occurring during this period. A change in the hormonal balance also occurs during puberty. In this paper, we present two young patients with large pyogenic granulomas and suggest that the hormonal changes play a primary role in the pathogenesis of this tumor.

Early immobilization of mandibular fractures: a retrospective study.

This study reviews the treatment outcome of 204 fractures in 131 patients over a 33-month period. In the total group, an infection rate of 4.4% was experienced, which is comparable with other reports. However, in complaint patients immobilized within 72 hours of injury, there was a 0% incidence of bone infection in 111 fractures treated by closed reduction and a 2% (one case) incidence of bone infection in 50 fractures treated by open reduction. Thus, of the of 161 fractures treated by closed and/or open reduction with early immobilization in complaint patients, the incidence of posttreatment bone infection was 0.6%. It was not significant whether teeth in the line of fracture were retained or removed. This study supports the principle that compound fractures of the mandible should to be immobilized within 72 hours of the initial trauma.

Augmentation of the atrophic edentulous maxilla with hydroxylapatite.

A technique for augmentation of the severely atrophic edentulous maxilla is presented. This technique combines the mobilization of the available soft tissue of the labial vestibule with a subperiosteal reflection and "filleting" of the redundant crestal soft tissue to create ample space to accommodate the insertion of the desired amount of hydroxylapatite. The surgical development of a distinct labial periosteal flap by both a subperiosteal and supraperiosteal dissection allows a two-layered lapped closure of the mucosal and periosteal flaps. Fourteen patients were treated with this technique and have been observed for period of 8 to 40 months. Arch form was dramatically improved in all cases. Observation of panoramic radiographs disclosed an average initial increase in ridge height of 11.8 mm in the midline and 7.6 mm in the first premolar regions. During the first 6 months, consolidation of the ridge occurred, but the diminution in ridge height never exceeded 15%.

A prospective double-blind evaluation of penicillin versus clindamycin in the treatment of odontogenic infections.

In a prospective, double-blind trial, penicillin and clindamycin were compared in treatment of moderate to severe orofacial infections of odontogenic origin, which yielded pus on aspiration. Among 27 patients randomized to receive penicillin, 22 (81%) had a successful outcome, and five (19%) were improved. In the 28 clindamycin-treated patients, 23 (82%) had a successful outcome, and five (18%) were improved. No failures were noted in either group. One patient who was receiving penicillin and two who were receiving clindamycin developed diarrhea. Bacteriologic results showed an average of 6.1 organisms per culture (2.5 aerobes and 3.6 anaerobes). Resistance rates for anaerobic isolates were 8.9% to penicillin and 1.9% to clindamycin. It was concluded that penicillin and clindamycin produce similar good results in treating odontogenic infection when the rate of penicillin resistance among oral anaerobic bacteria is at a relatively low level.

Arthrogryposis multiplex complex involving the temporomandibular joint.

A case of arthrogryposis multiplex complex involving the temporomandibular joints is reported. The anatomy and physiopathology of the arthrogrypotic articulation are reviewed. The role of biomechanical factors in the development and maintenance of joint surfaces is discussed. Treatment modalities are proposed.

The Goldenhar syndrome: diagnosis and early surgical management.

The diagnosis, classification, pathogenesis, and surgical treatment of a child with Goldenhar syndrome is reviewed. Our experience with early costochondral growth center transplantation to the temporomandibular joint and ramus is discussed.

Perspectives on massive osteolysis. Report of a case and review of the literature.

Massive osteolysis is a rare, chronic disease characterized by the progressive dissolution of contiguous osseous structures. There is no regeneration following the osteolysis. Pathologic fracture often leads to its discovery. The etiology and pathophysiology of the disease remain obscure. Chemo- and radiotherapeutic attempts at arresting the osteolytic process are generally unsuccessful. Bone grafting has proved disappointing, as the graft usually undergoes osteolysis. A new case of facial bone involvement in a 13-year-old boy is presented. The literature is reviewed, and the clinical experience gained from treating the disease is discussed.

Autogenous dermal grafting vestibuloplasty in dogs.

Vestibuloplasties were done in dogs, using autogenous dermis as a graft material. Clinical and histologic examination was done at 10, 17, 21, and 28 days. Results showed good graft take and a final appearance resembling that of mucosa. Histologic findings correlated well with clinical appearance. From this investigation it appears that the dermis acts as a true graft and not just as a biologic dressing.