Faculty Bibliography

Although root fractures are among the less common oral injuries (6 percent), a careful diagnostic evaluation of such injuries is required to arrive at an appropriate treatment plan. The position of the fracture in the root will determine the proper management. The problem of luxation due to trauma often involves the use of dental splints, which, if not properly designed, may cause root resorption, loss of alveolar bone, pulpal necrosis and pulp canal obliteration. The guidelines for the type of splint to use and conditions under which it should be placed are presented

PURPOSE/OBJECTIVE:This cadaver dissection studied the relationship of the buccal branch of the facial nerve to the parotid duct and its relevance to surgical procedures in this area. MATERIALS AND METHODS/METHODS:Ten cadaveric heads (twenty sides) were dissected. The superficial tissues were removed, and the buccal branch of the facial nerve and the parotid duct were identified. The vertical and horizontal relationships were recorded and analyzed. RESULTS:Eighty-five percent of the cadavers had a single buccal branch of the facial nerve, whereas 15% had two branches. In 75% of cases, the nerve was inferior to the duct as it emerged from the parotid gland, whereas in 25% of cases the nerve crossed the duct, usually from superior to inferior. CONCLUSION/CONCLUSIONS:The buccal branch of the facial nerve has a close relationship with the parotid gland for over 2.5 cm after it emerges from the parotid gland; it normally lies inferior to the duct. This relationship is of importance in performing parotid gland surgery, parotid duct surgery, and some facial cosmetic surgery.

PURPOSE/OBJECTIVE:This study evaluated the relationship of the mandibular third molar to the lingual nerve. MATERIALS AND METHODS/METHODS:An anatomic dissection of the lingual nerve in the third molar region was done on 20 cadavers (40 sides). RESULTS:The position of the nerve on one side bore no statistical relationship to the position of the nerve on the opposite side. The position of the lingual nerve was variable in both the sagittal and coronal planes. In two specimens the nerve lay superior to the lingual plate and in another the superior surface of the nerve was level with the crest of the lingual plate. CONCLUSION/CONCLUSIONS:These findings have implications for the avoidance of lingual nerve damage during surgery in the third molar and retromolar region of the mandible.

PURPOSE/OBJECTIVE:There are little data available on the prevalence of human immunodeficiency virus (HIV) disease and its relationship to postoperative infection in patients presenting with mandibular fractures. This retrospective study assesses these parameters. PATIENTS/METHODS:The study population consisted of 251 patients treated for mandibular fractures at San Francisco General Hospital (SFGH) between January 1990 and December 1993. Group 1 (n = 20) was composed of patients with documented HIV infection and group 2 (n = 231) served as controls. The groups were comparable with regard to age, sex, etiology, and number and types of fractures. RESULTS:HIV prevalence for this population was 7.9%, and was consistent with previously documented prevalence studies in SFGH surgical patients. In the HIV-positive group, 6 of 20 patients (30%) developed postoperative infection: 2 soft tissue (10%) and 4 bone-related (20%). In the control group, 22 of 231 patients (9.5%) developed postoperative infections: 16 soft tissue (6.9%) and 6 bone-related (2.6%). Statistical analysis showed a significant difference between the two groups with regard to overall (P = .016) and to bone-related (P = .001) infection rates. There was no statistically significant difference in soft tissue infections between the two groups (P = .953). The rate of postoperative infection was significantly higher in those patients (both HIV-positive and controls) who had open reduction and internal fixation (ORIF; 25/155; 16%) versus those who had closed reduction and maxillomandibular fixation (3/96; 3.1%; P = .003). The postoperative infection rate after ORIF was significantly higher in the HIV-positive (5/11; 45%) compared with the control group (20/144; 13.9%; P = .02). CONCLUSIONS:The results of this study indicate that the overall rate of postoperative infection after treatment of mandibular fractures is significantly higher in HIV-positive than in HIV-negative patients. Specifically, the use of ORIF in HIV-positive patients represents a significant risk.

We present two cases of massive gingival enlargement and osteolysis of alveolar bone in a 30-year-old female and a 36-year-old male. The etiology could not be established in either case. Histologically, both lesions contained hyperplastic fibrous connective tissue and intense plasma cell infiltrates. Both patients responded well to extensive gingivectomy, extraction of all teeth, and alveoplasty

20 cadaver mandibles were studied for the presence of an antilingula and its relationship to the true lingula and mandibular foramen. Three independent observers evaluated the mandibles for the presence of an antilingula. It could be identified on all 40 sides. On 9 of the sides, there was complete concordance on the position of the antilingula between the three observers. On the other 31 sides, however, there was a variation between observers of up to 11 mm. In only 43% of the cases was the antilingula within 5 mm of the true lingula. In most cases, the true lingula was postero-inferior to the antilingula. There was a negative horizontal and positive vertical correlation between the position of the antilingula on one side and its position on the contralateral side

The structure of the submental platysma muscle was evaluated in 20 preserved cadavers. Four distinct patterns were identified, depending on the pattern of merging of the right and left platysma bundles. Fifteen percent of cases showed a complete platysma diaphragm submentally, while in the other 85% there was some degree of midline dehiscence. In the 85% of cases where right and left fibers merged or crossed to form a V or U shape, the apex of the V or U was measured relative to the chin point. The distance between right and left fibers was measured at two locations posterior to the chin point. The width of the midline dehiscence (when present) was 6-24 mm (mean 11.8 mm) 1 cm posterior to its apex and 10-44 mm (mean 20.00 mm) 2 cm posterior to the apex. The wider and more divergent the dehiscence and the more U-shaped the dehiscence between left and right platysma bundles, the greater may be the tendency to a 'turkey gobbler' deformity with inadequate medial support for the skin and subcutaneous tissues

This study examines the histologic and biochemical features of wound healing in a cleft lip model in the mid-third-trimester fetal rabbit. At days 1, 2, and 4 after the procedure, control, unrepaired, and repaired fetal heads were obtained, sectioned, and stained for histologic examination. The localization of hyaluronic acid in the wound was documented using a cartilage-derived hyaluronic acid-binding protein. In both repaired and unrepaired wounds, the fetal cleft healed without inflammatory cell infiltration or scar formation. Six months after birth, the repaired cleft showed complete regeneration of muscle across the wound and the collagen fibers were of normal density and orientation. Decreased hyaluronic acid deposition was observed in unrepaired clefts as compared with adjacent tissue; no such difference was detected in repaired clefts. Our findings support the hypothesis that a cleft lip repaired in utero heals without the scarring that accompanies postnatal repair. This may explain the lack of maxillary growth restriction after in utero cleft lip repair.

We have previously described a model for in utero cleft lip repair in rabbits. Cleft lip and alveolus (CL) were created in fetal rabbits at 24 days gestation (term, 31 days). In this study, postnatal maxillary growth was evaluated in three groups of animals: 1) unoperated controls, 2) unrepaired CL, and 2) repaired CL. The animals were killed at 4, 12, and 26 weeks after birth. Direct cephalometry was performed on dry skulls to evaluate premaxillary width, anterior maxillary length and width, and posterior maxillary width. The results of this study indicate that rabbits that undergo an in utero CL procedure, with or without repair, exhibit no significant decrease in maxillary length and width when compared with controls.