Roy S. Feldman

Influence of cigarette, pipe, and cigar smoking, removable partial dentures, and age on oral leukoplakia

Oral leukoplakia, a potentially malignant lesion, has been associated with tobacco smoking, but few studies have investigated the influence of different products on lesion prevalence. In the current study 925 healthy male subjects from the Veterans Administration Dental Longitudinal Study were examined for lesion site and prevalence. The participants were grouped according to smoking status: nonsmokers, smokers of cigarettes, cigars, a pipe, cigars plus a pipe, or cigarettes plus another tobacco product. In addition, the amount of product smoked, presence of a removable partial denture, and age were examined to determine their relation to leukoplakia prevalence. The data indicated that cigar smokers had significantly fewer lesions than the other smoker groups and that persons smoking a pipe or a pipe plus cigars had the highest prevalence. Heavy cigarette smokers had significantly more palatal lesions than light to moderate cigarette smokers. While removable partial dentures did not appear to affect lesion prevalence significantly, older smokers, persons of 50 years and above, had a significantly higher prevalence than persons less than 50 years of age.

Six-year report of the periodontal health of fixed and removable partial denture abutment teeth

There were minimal differences in longitudinal periodontal effects when fixed and removable partial dentures were compared. Both treatment alternatives provide long-term periodontal health and should be considered for the restoration of a partially edentulous arch. Regardless of treatment, conscientious home care and professional prophylaxis are recommended.

Parathyroid hormone and calcitonin interactions in bone: Irradiation-induced inhibition of escape in vitro

SummaryCalcitonin (CT) inhibits hormonally stimulated bone resorption only transiently in vitro. This phenomenon has been termed “escape,” but the mechanism for the effect is not understood. One possible explanation is that bone cell differentiation and recruitment of specific precursor cells, in response to stimulators of resorption, lead to the appearance of osteoclasts that are unresponsive to CT. To test this hypothesis, cell proliferation in neonatal mouse calvaria in organ culture was inhibited by irradiation from a cobalt-60 source. At a dose of 6000 R, [3H]thymidine incorporation into intact calvaria was inhibited approximately 90%. Irradiation had no effect on the resorptive response to 0.1 U/ml parathyroid hormone (PTH). However, irradiation induced a dose-dependent inhibition of the escape response which was maximal at 6000 R. A dose of 6000 R did not affect the binding of125I-salmon CT to calvaria and decreased PTH stimulation of cyclic AMP release from bone without affecting the cyclic AMP response to CT. Although irradiation caused a dose-dependent inhibition of DNA synthesis, the dose-response curves for that effect and inhibition of escape were not superimposable.A morphologic study of hormonally treated calvaria demonstrated that irradiation prevented the early increase in number of osteoclasts in PTH-treated calvaria that had been observed previously in unirradiated bones. Autoradiography showed that irradiation also prevented the PTH-stimulated recruitment of newly divided mononuclear cell precursors into osteoclasts. This may be correlated with the effect of irradiation to prevent the loss of responsiveness to CT in the presence of PTH.