Abrasion of human enamel and dentine caused by toothpastes of differing abrasivity determined using an in situ wear model

Objectives : To determine the rates of enamel and dentine wear in situ during tooth brushing with a range of five toothpastes of differing RDA and REA values. Methods : Enamel/dentine inserts were placed in the buccal aspects of full upper dentures of human volunteers. Enamel wear was determined by change in Knoop indent length and dentine wear was determined from the enamel‐dentine step height, measured using optical profilometry. Results : Significant differences between the test products were found for both enamel and dentine (p < 0.05). However for the conventional toothpastes the rate of wear was similar and differences between the products were not generally statistically significant for either enamel or dentine, despite the fact that their RDA values differed by more than a factor of two. The rate of wear was found to decrease throughout the duration of the study. Conclusions : The study demonstrated that the methodology used is capable of assessing enamel and dentine wear in situ within a relatively short period of time. The data suggest that whilst in vitro tests have value in understanding differences in abrasivity between products, they cannot be used to predict in vivo effects.     

The effect of sectioning the trigeminal sensory root on the periodontally-induced jaw-opening reflex

The experiment was designed to determine the pathway taken to the brain stem by periodontal afferents responsible for the digastric jaw-opening reflex induced by tooth-tapping. Cutting the trigeminal sensory roots of anesthetized decerebrate cats eliminated the ipsilateral periodontally-induced reflex, although the stretch reflexes of the jaw-closing muscles were undiminished. These results suggest that periodontal afferents causing the jaw-opening reflex reach the brainstem through the Vth sensory root, and confirm that muscle spindle afferents travel through the Vth motor root.     

The use of infrared thermography in the evaluation of oral lesions

This study was conducted to quantitate the degree of inflammation associated with oral lesions by using infrared thermography. It was reasoned that the increased vascularity associated with inflamed tissue may result in measurable increases in surface temperature. One subject with normal oral mucosa and three subjects with oral lesions of varying causes were studied with a thermal video system, using an infrared imager and microprocessor. A clinical photograph of each subject was obtained. Multiple thermograms were made in a temperature range of 30.0 C to 34.2 C at a sensitivity of 0.2 C. Photographs were taken on different occasions to determine whether the temperature readings could be duplicated and to test the accuracy of each reading. The normal surface temperature of the control subject's mucosa was significantly cooler than were the temperatures of the inflamed areas in the subjects with lesions induced by chemotherapy. The temperature of the areas of stomatitis was consistent (subject 3, mean = 33.7 C; subject 4, mean = 33.9 C). The necrotic center of a traumatic ulcer inhibited measurement of an underlying inflamed base and, thus, was equivalent to the control in temperature (subject 1 (control), mean = 31.9 C; subject 2 (necrotic lesion), mean = 31.7 C). These results suggest that infrared thermography may provide a means to quantitatively assess the degree of mucosal inflammation.     

Radiographic detection of porosities in removable partial denture castings

The purpose of this study was to discern the existence of structural defects in removable partial denture frameworks by means of radiographs. A simple technique was described using a dental radiograph unit and routine periapical dental films. All components of removable partial denture castings were radiographed with different angulations. The visibility of defects was clear. Structural defects were located and classified in two brands of removable partial denture base metal alloys (Ticonium and Nobilium) commonly used in fabrication of removable partial denture castings. The technique described is simple, inexpensive, not time-consuming, and can be implemented with minimum instrumentation. Future studies with this radiographic method for investigation of internal defects in fixed prostheses or dental implants are recommended.     

Hemodynamic effects of molsidomine on weight sustaining isometric exercise in patients with ischemic heart disease

Hemodynamic effects of 2 mg of sublingual molsidomine were evaluated in 11 patients with ischemic heart disease using a weight-sustaining isometric exercise (WSIE) that we developed. Left ventricular end diastolic pressure (LVEDP), mean pulmonary pressure, mean systemic arterial pressure (mAP), cardiac index and stroke work index increased significantly during WSIE before and after molsidomine. Although WSIE resulted in a similar rise of mAP before and after molsidomine, the increment value of LVEDP during WSIE was significantly lower after molsidomine. The recovery time to the resting state of all parameters was shorter and the left ventricular function curves showed a leftward deviation with molsidomine. In conclusion, the results suggest that molsidomine will produce a preload reduction and improve the left ventricular function during WSIE in patients with ischemic heart disease.     

Immunoelectron microscopic findings in oral mucosa of patients with dermatitis herpetiformis and linear IgA disease

Two patients with dermatitis herpetiformis and one with linear IgA disease were examined. Two of the patients had oral lesions and all three showed IgA deposits detected by direct immunofluorescence in apparently normal buccal mucosa. To localize the target structures for IgA deposition, biopsy specimens were taken from normal appearing buccal mucosa for immunoelectron microscopy. The patients with dermatitis herpetiformis had distinct IgA deposits in the upper connective tissue. These were often associated with elastic fibers and occasionally also with capillary walls. In contrast, the patient with linear IgA disease had IgA deposition at the subbasal lamina. Though the clinical expressions may be similar the present immunoelectron microscopic findings in oral mucosa clearly differentiate dermatitis herpetiformis from liner IgA disease.     

A case: control study of oro-facial clefts in Western Australia

A bstract — A case: control study was undertaken using all children with oro-facial clefts born between 1 January 1982 and 14 April 1984 and conceived in Western Australia (WA) — a total of 90 cases and 180 matched controls. Information on all cases and controls was obtained from hospital records and a postal questionnaire. A 92 per cent response rate was obtained from the mothers of affected children.
An excess of cleft lip with or without cleft palate (CL(P)) was confirmed for rural Western Australia and reasons for this finding proposed. Further information is presented on maternal age, parity, blood groups, paternal occupation, familial and syndromic clefts, maternal alcohol and cigarette consumption and history of previous miscarriages.     

Immunohistochemical and ultrastructural demonstration of keratin in epi-myoepithelial islands of autoimmune sialadenitis in man

Immunohistochemistry of salivary gland suggested that keratin is a specific marker of duct-epithelial cells and myosin for myoepithelial cells. Epi-myoepithelial islands found in some autoimmune sialadenitis, such as Sjögren's syndrome, were mainly composed of keratin-positive cells. Keratin filaments, with bundles and desmosome-attachments were invariably found in epithelial cells with electron microscopy. The islands contained no cells with myoepithelial characteristics. The findings show that there is no obvious participation of myoepithelial cells in the growth of the epi-myoepithelial islands.