Sheldon Rovin

Aggressive growth and neoplastic potential of odontogenic cysts: with special reference to central epidermoid and mucoepidermoid carcinomas.

An aggressive form of odontogenic cyst known as the keratocyst has been reviewed with a report on the findings of 70 new instances. Recurrence after 2 years of followup was found to be 20%. From both a review of the literature and original cases, carcinomatous and ameloblastomatous transformation in odontogenic keratocysts seems to be an extremely rare phenomenon. Alternatively, epidermoid carcinoma and mucoepidermoid carcinoma arising centrally within the jaws are often associated with other types of dental cysts. Review of 36 instances of central epidermoid carcinoma has disclosed that 75% were associated with a cyst lining; the 2‐year survival rate was found to be 53%. Central mucoepidermoid carcinoma was associated with a dental cyst or impacted tooth in 48% of the cases, and enjoyed a 100% 2‐year and 5‐year survival; however, 2 patients were recorded alive with disease at 4 months and 10 years, whereas another patient succumbed to disease 14 years post‐operatively.

Verrucous squamous cell carcinoma of the oral cavity

Verrucous‐type oral tumors have been reviewed. This variety of epidermoid carcinoma of the oral cavity presents as a warty growth in patients who have a history of chewing tobacco and poor oral hygiene. They are slow‐growing, locally invasive, and do not metastasize to lymph nodes in our experience. In five of these patients, the microscopic pattern was that of a well‐differentiated squamous cell carcinoma. The others presented the classical histologic pattern of verrucous carcinoma. No difference was found in the behavior of these two groups. Three cases developed anaplastic transformation after irradiation and surgery. A change in the clinical behavior of the tumor was observed in these patients and all three died. There is some possibility that ionizing radiations could be the trigger mechanism in this transformation. The authors feel that surgery is the treatment of choice in early or easily resectable lesions. It would appear unnecessary to perform neck dissection in these patients. Radiation therapy should be used in advanced verrucal‐type lesions in which surgical resection is difficult or not feasible. These patients require frequent and careful observation. The authors believe that this entity deserves further investigation.

Diphenylhydantoin Sodium (Dilantin) as a Caries Retarder

Rats that had their mandibular first molars silk-ligated and that were fed chow with diphenylhydantoin sodium (Dilantin) developed less caries than rats that were not fed Dilantin. The retarding effect of Dilantin was enhanced by the cleanliness of the environment in which the animals lived.

Caries Due to Food Retention in Nonsusceptible Rats Fed a Noncariogenic Diet

Ligation of mandibular first molars in Fischer rats resulted in extensive food retention and massive caries, although the rats were fed a high fluoride, noncariogenic diet. These experimental conditions were suggested as a model to study the relationship of food retention to caries.

Blood Flow, Collagen Components of Oral Tissue and Salivary Kallikrein in Young to Senescent, Germfree and Conventional Rats

In oral tissues of rats, progress of age resulted in a gradual reduction of regional blood flow and in decreased levels of eluable (labile) hydroxyproline from the collagen component. These were paralleled by an increment of salivary kallikrein. The presence of the microbial flora in the oral cavity, portrayed by the comparison of conventional and germfree rats, caused an elevation of blood flow in all age groups, without exerting a marked effect on eluable hydroxyproline. In addition to aging and flora effects, the action of chronic hypoxia and of mechanical stress has been observed on the mentioned parameters. The presently used animal models and experimental design permit a critical study of etiologic agents and characteristic lesions of peridontal disease.