Evaluation of a technique for recording temporomandibular joint sounds.

Analysis of temporomandibular joints sounds may contribute to the differential diagnosis of temporomandibular joint disorders. In this article an advanced system for the recording of joint sounds is presented. The method proved to be reliable. The problem of filtering out artifacts has been solved to a great extent but not completely. Temporomandibular joint sounds measured with this technique vary considerably in energy, frequency spectrum, and peak-to-peak amplitude over 3 months, as well as within 1 day. These differences seem to reflect natural variations in joint sounds caused by the physical impossibility of performing identical jaw movements. The results indicate that joint sound characteristics do not yet offer a solid basis for inferences concerning the development of temporomandibular joint abnormalities in the clinical setting.     

Amalgam use and mercury emission in the Netherlands

An overview is presented of the emission of mercury to the environment by restoring teeth with amalgam, extraction, replacement of amalgam, and the final phase of teeth. Important input data were the trade figures of amalgam. The emission of mercury from amalgam fillings are characterized by diffuse spreading. Many small sources are together a substantial source of the leakage of mercury to the environment. Amalgam adhering to cotton-wool and in extracted teeth deliver a relevant contribution to the mercury load in municipal waste. The total mercury emission from dental amalgam to the environment in the Netherlands is at the estimate 500 kg a year, with a worst case maximum of 935 kg.     

Oral microbiota in smokers and non-smokers in natural and experimentally-induced gingivitis

Abstract. The present study primarily aimed at investigating the oral microbiota in smokers and non-smokers with established gingivitis and monitoring its composition during experimental gingivitis. Secondly, it aimed at examining whether the composition of the microbiota is associated with different levels of gingival inflammation during this experimental gingivitis trial. For this purpose, 25 non-dental university students with gingivitis were recruited. 11 subjects were smokers and 14 were non-smokers. After achieving gingival health, they entered a 14-day experimental gingivitis trial. Plaque and bleeding were assessed before entering into the study (intake), at day 0. day 5 and at day 14 of the experiment. Microbiological samples from mucosal sites and dental plaque (taken at intake, day 0, and day 14) were analysed for the presence of Actinomyces species. Actinobacillus actinomycetemcomitans, Bacteroides forsythus, Campylobacter rectus, Fusobacterium nucleatum, Peptostreptococcus micros. Porphyromonas gingivalis, Prevotella intermedia and Streptococcus species. At day 14 of the experimental period, the level of plaque formation was not different between smokers and nonsmokers, but bleeding scores were lower in smokers than in non-smokers (15% and 30%) respectively, p= 0.01). The change from natural gingivitis to a state of gingival health and a subsequent change from gingival health to experimentally induced gingivitis was accompanied by quantitative alterations in the cultivable microbiota in both groups. Changes were most prominent in the transition from gingival health to experimental gingivitis and were found in dental plaque for Actinomyces species, C. rectus, F. nucleatum, and P. intermedia. Within the group of non-smokers, a distinction was made between subjects with a‘weak’or 'strong’inflammatory response. No relationship with a single bacterial species could be established which would likely explain the differences in levels of inflammation. It is concluded that differences in response to experimental gingivitis are not caused by major differences in the composition of the oral microbiota.     

The culture of human buccal and vaginal epithelial cells for permeability studies.

The objective of the present study was to develop a single improved technique to culture human vaginal and buccal epithelial cells, whereby the cultured cells can be used in drug permeability studies. Cells were obtained from healthy human vaginal and buccal mucosa following vaginal hysterectomies and various oral surgical procedures. Tissue obtained was washed extensively in phosphate buffered saline (PBS, pH 7.3) containing antibiotics and amphotericin-B. Tissue specimens were cut into small pieces and plated out in 24-well plates. After drying, the full medium was added. Cell growth occurred within 4-6 days from primary explants and confluency was reached within 2-3 weeks. Primary explants yielded epithelial cells with minimal fibroblast contamination. After trypsinization, cells were seeded into collagen-coated wells and onto Transwell membranes. Trypsinized cells grew best on collagen-coated surfaces yielding more than one layer. The average steady state flux for the collagen-coated membranes (ccm's) containing either buccal or vaginal epithelial layers towards water was 6-10 times lower than that found for the cell-free ccm's. Fluxes for cultured cells on ccm's were 3x higher than those obtained for intact buccal and vaginal mucosa. Growth and permeability to water of the vaginal and buccal epithelial cells were comparable, confirming the similarity of these two tissues and the suitability of using the former as a model for the latter in permeability to tritiated water.     

Dermatography, a treatment for sequelae after head and neck surgery: a case report.

Two patients with discolouration fo skin grafts after head and neck surgery, were treated with dermatography, a refined method of tattooing, and with intra-cicatricial keloidectomy, of which the results are described.     

Attitude of a group of South Africans toward advertising by dentists in private practice]

The advertising of dental services in South Africa is controlled by rules and regulations of the South African Medical and Dental Council. According to these, advertising is not permissible with the exception of specified professional information which may be made known only by means of a nameplate and an entry in a telephone directory. Questionnaires were sent to a randomised sample of 2,100 persons in order to determine the attitude of South Africans towards advertising by private practitioners. According to information obtained from this study there is a strong indication that consumers of dental services prefer a freer form of advertising by dentists in the private practice.     

Applicability of osseointegrated oral implants in the rehabilitation of partial edentulism: a prospective multicenter study on 558 fixtures

Nine clinical centers using the Br?nemark System participated in a prospective study of 159 partially edentulous patients between 18 and 70 years of age. Clinical parameters evaluated were plaque index, gingivitis, pocket depth, bleeding index, tooth mobility, and stomatognathic function. Initially, 558 fixtures were placed and 521 remained in the study following prosthesis placement (199 prostheses in 154 patients). Fixtures were lost or unaccounted for because of nonintegration prior to prosthesis fabrication (19), patient withdrawal (11), prosthodontic reasons (6), and failure during prosthetic procedures (1). Failure was primarily attributable to unfavorable bone quality, sex (more in males), and smaller fixture size. Complications and failure related to other patient characteristics are presented. After 1 year of a 5-year study, preliminary results suggest that a success rate equal to or better than that obtained with edentulous patients may be expected.     

The fibroblast population in oral submucous fibrosis

The purpose of the investigation was to compare the morphology of fibroblasts cultured from healthy oral mucosa and mucosa of patients with oral submucous fibrosis (OSF) and to collate the occurrence of cell types of similar morphology. Cells cultured from biopsy specimens from the buccal mucosa of six subjects who did not chew the areca nut and six patients with OSF who chewed areca nut were grown according to standard techniques. Ninety cells per cell line were recorded daily for 8 days, classified into types F1, F2 and F3 according to their morphology, and the results statistically analyzed. We found that there was a relative increase of F3 cells in relation to Fl cells in OSF resulting in the ratio of F3 to F1 cells being significantly larger in OSF than the ratio in the controls. As it has been reported that F3 cells m rat connective tissues produce significantly more collagen types I and III than F1 cells, we concluded that a change of fibroblast population has occurred in OSF and that this relative increase of F3 cells in humans, which could be committed to the production of large quantities of collagen, can be an explanation for the excessive collagen formation in OSF.