The prognostic value of histopathologic grading of oral squamous cell carcinomas (SCC) has varied from not any to highly significant. We have retrospectively studied all (130) SCCs registered in Norway 1963-72 in the buccal and maxillary alveolar mucosa. From 68 of these cases biopsy specimens of acceptable quality were obtained. Broders' method of grading was compared with a modification of a recent malignancy grading system recommended by Anneroth et al. which was performed only within the histologically most invasive areas of the tumors. Cox's multivariate survival analyses showed that this grading in the invasive sites had highly significant prognostic value. Broders grade had no prognostic value. The stage of tumor had also prognostic value. These highly significant results indicate that the histologically invasive areas may be primarily responsible for the clinical behavior of the tumor, and this may be of importance for the choice of therapy for oral SCC.

Vincristine in doses of 0.1, 0.3, 0.5 and 0.7 mg/kg was administered to 60 rats in four groups. Histomorphologic investigation of the odontoblast population in the maxillary incisors revealed dose-dependent reactions consisting of (1) swelling of the odontoblasts and an accumulation of abnormal mitotic cells in the germinative parts ofthe pulp after 5 h, (2) a supervening necrosis and destrucdon of some odontoblasts and ofthe mitotic cells after 24 h, and (3) after 3 d, a reversal to normal structure in some parts ofthe odontoblast population, but a further development ofthe vincristine-induced changes, with severe cellular derangement and irregular predentin production, in others.

– A preliminary report on the histomorphologic effects of vincristine on rat incisor dentinogenesis is presented. Niche‐like areas of osteodentin and a faint incremental line in the dentin were the main derangements observed after single injections of the drug. The severity of the lesions was dose‐dependent.

– Vincristine was administered to 60 rats in four groups in doses of 0,1, 0,3, 0,5 and 0.7mg/kg. Histomorphologic investigation of the dentin and odontoblasts in the maxillary incisors after 1, 2 and 3 weeks revealed a moderate to severe disturbance of dentin production in some parts of the incisors. In some of the affected areas the effect seemed to be reversible in that normal‐appearing dentin was found pulpal to the dentinal derangements after 2 and 3 weeks. The distribution and severity of the lesions were similar to those previously observed 3 days after injection of the same doses of vincristine.

– 0.7 mg/kg VCR was given to nine rats in three experimental groups. Twenty‐three hours after VCR injection the animals were injected with 3H‐thymidine. The animals were sacrificed 24, 48 and 72 h after the VCR injection, and by comparison with nine control animals similarly injected with sodium chloride solution and nucleotide, it was shown that VCR causes a delayed migration of pulp cells from the proliferative pool and a small but distinct inhibition of the incisal growth of the incisors. The growth inhibition corresponded to the normal growth over a 24‐h period in nou‐VCR‐injected animals.