Re-epithelialization of human oral keratinocytes in vitro.

Re-epithelialization involves interactions between keratinocytes and the extracellular matrix upon which these cells move. It is hypothesized that keratinocytes are activated when wounded, and the resultant phenotypic change directs re-epithelialization. We have adapted organotypic cultures, in which oral gingival keratinocytes are fully differentiated, to study re-epithelialization following wounding. To elucidate keratinocyte behavior and phenotype during re-epithelialization, we have investigated this process in the presence and absence of the growth factor TGF-beta 1 and have monitored expression of MMP-1 (Type I collagenase) mRNA by in situ hybridization. In addition, we have followed proliferation and migration of wound keratinocytes by genetically marking these cells with a retroviral vector and by measuring their proliferative index. We found that keratinocytes grown without TGF-beta 1 were hyperproliferative in response to wounding, and re-epithelialization was complete by 24 h. However, 2.5 ng/mL TGF-beta 1 induced a transient delay in re-epithelialization, a reduction in proliferation, and fewer clusters of genetically marked cells. Keratinocytes expressed MMP-1 mRNA only when they covered the wounded surface, suggesting that the cells acquire a collagenolytic phenotype during re-epithelialization and that contact with different ECM components may modulate keratinocyte expression of MMP-1. We conclude that the phenotype of oral keratinocytes is altered during re-epithelialization in vitro and that this process is modulated by TGF-beta 1. Re-epithelialization occurs as keratinocytes are activated to move over the wound bed. Understanding the phenotype of wounded keratinocytes may facilitate treatment of chronic oral wounds and periodontal disease.

Touton-like giant cells in periapical granulomas.

Two types of multinucleated giant cells were observed in periapical granulomas--the foreign body type and the Touton type. In the Touton type, the nuclei were near the center of the cell, surrounded by foamy cytoplasm. Both types of giant cells reacted positively to lysozyme, alpha 1-antitrypsin and alpha 1-antichymotrypsin, indicating their histiocytic origin.

The fate of genetically marked human oral keratinocytes in vitro.

The fate of the progeny of human oral gingival keratinocytes was mapped in stratified epithelial tissues in vitro by following the expression of a marker gene in genetically related clones. Oral epithelial progenitor cells were genetically marked at high efficiency by transducing them with a retrovirus vector that carried the gene for a histochemically detectable product, Escherichia coli beta-galactosidase (beta-gal). These cells were then grown in submerged cultures and on collagen rafts at the air-liquid interface to demonstrate the distribution of genetically marked cells in a differentiating tissue in vitro. The dynamics of transduced cells showed that clonally related cells were arranged in discrete units of labelled cells and these clusters were defined as 'clonal proliferation units'. The size and configuration of these units were related to the proliferative potential and differentiating capacity of the cell that was initially transduced. This model demonstrates the relation between clonally related cells and tissue architecture for oral keratinocytes in vitro.

Surgical excision of a congenital lateral fistula of the upper lip. An intra-oral approach.

A new technique for removal of a congenital lateral upper lip fistula is described, using an intra-oral approach. Previous reports of removal of such a congenital malformation have used an extra-oral approach. The technique described allows for excellent visualization of the fistula without cutaneous lip incision. Using this approach, good aesthetic results and complete removal of the fistula and associated mucous glands can be obtained.

A technique for the treatment of mandibular body fractures in young children.

Mandibular body fractures in young children are uncommon, yet their treatment and management often present several difficulties. The presence of developing dental follicles may lead to irregular fracture lines and precludes the use of intraosseus wiring. In addition, treatment of fractures in children of this age requires a technique that limits the number of separate procedures that they are subjected to. The technique outlined below for the treatment of mandibular body fractures in young children, uses a plastic impression tray as a splint and provides a simple means for their reduction and fixation.

Aneurysmal bone cyst of the mandible.

The case of a 48-year-old male patient with a slowly growing mass in the right molar region of the mandible is presented. The biopsy specimen showed an aneurysmal bone cyst. After radiation therapy failed to arrest the process, the patient was treated surgically via an external approach. Between the time of the initial presentation and the date of definitive surgery 9 months later, a dramatic change was noted in the roentgenographic pattern of the lesion, demonstrating early and late stages in the development of an aneurysmal bone cyst. There has been no recurrence in a 17-year follow-up period.

Head and neck manifestations of tumoral calcinosis.

Intraoral facial and laryngeal features of tumoral calcinosis are reviewed in six patients of Jewish-Yemenite descent. Extraoral features included calcified masses, erythematous patches, and angular cheilitis. Oral soft tissue findings included papillary hyperplasia of the lip vermilion and velvety-red macules on the tongue, palate, and buccal mucosa. Gingival findings included advanced periodontitis and an erythematous marginal gingivitis. In all patients, orthognathic evaluation revealed a concave profile, retruded maxilla, and relative mandibular prognathism. Although previously reported clinical dental abnormalities were not present, extracted teeth demonstrated abnormal dentin. Hoarseness was present in all patients and was the earliest appearing feature in two patients. The appearance of these head and neck findings preceded the classical manifestations of tumoral calcinosis and may be helpful in the early diagnosis of this entity. The varied reported features of tumoral calcinosis support the notion that this disease may present multiple formes frustes with variable clinical expressivity.

Simultaneous occurrence of a congenital lateral upper lip sinus and congenital gingival cyst: a case report and discussion of pathogenesis.

The simultaneous occurrence of a congenital lateral sinus of the upper lip and of a congenital gingival cyst in a newborn boy is reported. The sinus extended to a depth of 10 mm and was lined by a parakeratinized squamous epithelium. The gingival cyst appeared as a 1 cm palatal enlargement lingual to the maxillary alveolar ridge and demonstrated a thin epithelial lining with localized plaquelike thickenings and occasional clear cells with vacuolated cytoplasm. There was no familial history of congenital deformities, and no additional abnormalities were noted. These two epithelium-lined structures show a clear topographic and morphologic relationship, and they may share a common embryologic origin. It is suggested that they derive from epithelium remaining subsequent to the union of the maxillary process and medial nasal process mesoderms.