Porosity of different dental luting cements.

OBJECTIVE: The aim of this in vitro study was to compare open porosity and pore size distribution of different types of luting cements (zinc phosphate and polycarboxylate produced by Harvard Cement, Great Britain, glass-ionomer product GC Fuji I, GC Corporation, Japan, and Panavia F, resin based composite cement, Kurraray Co. Ltd. Japan) using mercury intrusion porosimetry and use it as an additional parameter for ranging the quality of cements used in prosthetics. METHOD: Samples were hand mixed in accordance with the manufacturer's instructions and formed in cylindrical test specimens. Density of samples was determined using a pycnometer while porous structure was estimated using high pressure mercury intrusion porosimeter enabling estimation of pore diameters in interval 7.5-15,000 nm. RESULTS: The polycarboxylate cement posses the highest porosity and specific pore volume among investigated cements. By comparison of the results obtained for zinc phosphate and glass-ionomer cement, it can be observed that according to some textural properties zinc phosphate cement is better choice (smaller specific pore volume and absence of macropores larger than 1 microm) while according to other textural properties the glass-ionomer has advantage (smaller porosity). The resin based composite cement poses the most desired porous structure for prosthetic application among the investigated cements (the lowest porosity and specific pore volume and all identified pores are smaller than 20 nm). SIGNIFICANCE: Based on results of this study, it is possible to estimate the efficiency of luting cements to protect the interior of tooth from penetration of oral fluids, bacteria and bacterial toxins into unprotected dentine.     

The rise and fall of the Latino dentist supply in California: implications for dental education

The purpose of this study was to determine the number of Latino dentists in California, identify the schools and countries where they were educated, and compare Latino dentist demographics with that of the state's new demographics. From the 2000 California Department of Consumer Affairs list of 25,273 dentists, we identified Latino U.S. dental graduates (USDGs) by "heavily Hispanic" surnames and Latino international dental graduates (IDGs) by country and school of graduation. From the 2000 U.S. census Public Use Microdata Sample (PUMS), we described Latino dentist characteristics such as Spanish language capacity and practice location. The number of Latino dentists acquiring licenses to practice in California has fallen dramatically, by nearly 80 percent, between 1983 and 2000. This decline is not merely an affirmative action issue; it results in an issue of access. Latino dentists are far more likely to speak Spanish and be located in a heavily Latino area than non-Latino dentists. Currently, although the supply of Latino dentists is dwindling, the Latino population is growing rapidly. In California and out-of-state schools, first-year matriculation of Latino USDG must increase. Further, non-Latino dentists should be prepared and given incentives to learn Spanish and locate practices in areas of need. The reintroduction of IDG Latino dentists needs to be seriously considered.     

Comparative analysis of antimicrobial action of polyhexametylenguanide hydrochloride (Biopag) and chlorhexidine bigluconate upon potential infectious agent of suppurative-inflammatory diseases of maxillo-facial region and neck

Sensitivity of microflora representatives isolated from inflammatory foci from 40 patients with suppurative-inflammatory diseases of maxillo-facial region and neck to different concentrations of antiseptic preparations of polyhexametylenguanide hydrochloride (Biopag) and chlorhexidine bigluconate was tested. It was determined that 0.05-0.1% solutions of these antiseptics were optimal for these diseases treatment. Biopag had more pronounced fungicidal action, less toxic and more prolonged antimicrobial action and better organoleptic properties when compared with chlorhexidine bigluconate.     

Oral tuberculosis in an asymptomatic pulmonary tuberculosis

Tuberculosis (TB) has been a worldwide health problem for centuries. It most commonly affects the lungs, but rare oral manifestations of TB have been reported. The aim of this paper is to present a case of painful erythematous lesion of oral cavity in undiagnosed asymptomatic pulmonary tuberculosis. This case is unusual in that the appearance of the painful oral lesion caused the patient to seek professional care and was concurrent with quiescent pulmonary disease.     

Head immobilization can impair jaw function

Findings that jaw-opening/-closing relies on both mandibular and head movements suggest that jaw and neck muscles are jointly activated in jaw function. This study tested the hypothesis that rhythmic jaw activities involve an active repositioning of the head, and that head fixation can impair jaw function. Concomitant mandibular and head-neck movements were recorded during rhythmic jaw activities in 12 healthy adults, with and without fixation of the head. In four participants, the movement recording was combined with simultaneous registration of myoelectric activity in jaw and neck muscles. The results showed neck muscle activity during jaw opening with and without head fixation. Notably, head fixation led to reduced mandibular movements and shorter duration of jaw-opening/-closing cycles. The findings suggest recruitment of neck muscles in jaw activities, and that head fixation can impair jaw function. The results underline the jaw and neck neuromuscular relationship in jaw function.     

Loss of space and changes in the dental arch after premature loss of the lower primary molar: a longitudinal study

The purpose of the study was to evaluate the space changes, dental arch width, arch length and arch perimeter, after the unilateral extraction of lower first primary molar in the mixed dentition period. A longitudinal study was conducted among forty children in the age group of 6-9 years, who reported for extraction of lower first primary molar in the department of Pedodontics, Govt. Dental College, Trivandrum. Study models were made from alginate impression taken before extraction and after extraction at the periodical intervals of two months, four months, six months and eight months. The mesiodistal width of lower first primary molar of the non-extracted side was taken as the control. The results of the study showed statistically significant space loss in the extraction side ( P value < 0.01) and no significant space loss in the control side (P value > 0.05). The rate of loss was greatest in the first four months. The arch width, arch length and arch perimeter had no significant change from initial to eight months follow up. The present study challenges the use of a space maintenance under the circumstances of premature loss of mandibular primary molar for preventing space loss.     

Adult Dental Visits in California: Successes and Challenges

OBJECTIVES: This study sought to estimate and characterize the proportion of California adults who visited a dentist in the preceding year and to identify reasons for not going. METHODS: In 1995, 4,029 adults were interviewed by telephone as part of the California Behavioral Risk Factor Surveillance System. Items included recentness of a dental visit, dental insurance status, and number of teeth lost due to disease. Persons who had not seen a dentist within the preceding year were asked the main reason they had not gone. RESULTS: In 1995, 65.9% of adults reported visiting a dentist in the preceding twelve months. Use of dental services was greater among persons aged 35 years or older (70.4%) than among those aged 18-34 years (58.4%) and among those with dental insurance (74.9%) than those without (54.4%). Dental visits were less likely among adults living at or below 200 percent of the federal poverty level, those with less than a high school education, and the edentulous. Reasons most commonly cited for not seeing a dentist were no perceived reason to go (37.2%), cost (30.7%), and fear (9.2%). CONCLUSION: Substantial variation in use of dental services exists among California's adults. Achieving equity in access and opportunity for disease prevention in this state may require expanded dental insurance coverage and serious efforts in oral health promotion.     

A slow release calcium delivery system for the study of reparative dentine formation

Abstract— Several liquid, semi-solid and solid delivery systems were formulated and tested to devise a method of reproducibly administering accurate micro-doses of calcium into a 700 μm diameter cakity in a rat maxillary incisor tooth, in the absence of hydroxyl ions. Development of this delivery system was necessary to facilitate studies of the mechanisms of pulpal repair and odontoblast differentiation. The principal requirements for the delivery system were that it should be easily administered into a small pulp exposure in the rat incisor and that a greater than 1000-fold range in calcium ion concentrations could be incorporated and delivered for a period of 2–3 days, preferably in an acidic environment to minimize the effect of non-specific nucleation under alkaline conditions. Poly ethylene) glycol microspheres were found to be an ideal vehicle. Under the in vivo dissolution conditions used, complete release of all calcium salts occurred within 12–15 hours, except for the very water-insoluble calcium stearate. It was anticipated that the re lease of calcium ions would be significantly more prolonged in vivo because of the physical constraints of the prepared cavity as well as the restricted access to fluid flow.