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.     

Induction of IL-10-producing CD4+ T-cells in chronic periodontitis

Precise immunological aspects of inflamed gingival mucosa remain to be elucidated in the murine experimental periodontitis model; therefore, we have characterized the mucosal immune cells in the inflamed gingiva of mice with alveolar bone reduction. Mice were orally infected with Porphyromonas gingivalis 15 times over 2 weeks. Gingival mononuclear cells (GMCs) were isolated from P. gingivalis- and sham-infected mice 1, 7, 15, and 30 days after the last infection. Although the greatest degree of periodontitis was seen in P. gingivalis-infected mice at 30 days after infection, the highest levels of IL-6 and TNF-α production were noted in the GMCs isolated 7 days after infection. Further, the frequency of RANKL(+)CD4(+) T-cells in GMCs of inflamed gingiva peaked 15 days after infection. Importantly, the number of Foxp3(+)CD4(+) CD25(+) regulatory T (Treg)-cells was increased only in the experimental group 30 days after infection. Thus, intracellular cytokine analysis revealed an increased number of IL-10-producing CD4(+) T-cells in inflamed gingiva when compared with the control group. These results suggest that there are potential roles for Treg cells during the chronic stage of periodontitis in the regulation of gingival inflammation and alveolar bone loss.     

Influence of grinding procedures on the flexural strength of zirconia ceramics

The surface of zirconia may be damaged during grinding, influencing the mechanical properties of the material. The purpose of this study was to compare the flexural strength of zirconia after different grinding procedures. Twenty bar-type zirconia specimens (21 x 5 x 2 mm) were divided into 4 groups and ground using a high-speed handpiece or a low-speed straight handpiece until the bars were reduced 1 mm using two different grinding times: continuous grinding and short-time grinding (n=5). Control specimens (n=5) were analyzed without grinding. The flexural strengths of the bars were determined by using 3-point bending test in a universal testing machine at a crosshead speed of 0.5 mm/min. The fracture load (N) was recorded, and the data were analyzed statistically by the Kruskal Wallis test at a significance level of 0.05. In the test groups, high-speed handpiece grinding for a short time had produced the highest mean flexural strength (878.5 ± 194.8 MPa), while micromotor continuous grinding produced the lowest mean flexural strength (733.8 ± 94.2 MPa). The control group was the strongest group (928.4 ± 186.5 MPa). However, there was no statistically significant differences among the groups (p>0.05). Within the limitations of the study, there was no difference in flexural strength of zirconia specimens ground with different procedures.     

Oral health status of adults in Southern Vietnam - a cross-sectional epidemiological study

Background

Dental caries is one of the primary causes of tooth loss among adults. It is estimated to affect a majority of Americans aged 55 and older, with a disproportionately higher burden in disadvantaged populations. Although a number of treatments are currently in use for caries prevention in adults, evidence for their efficacy and effectiveness is limited.

Methods/Design

The Prevention of Adult Caries Study (PACS) is a multicenter, placebo-controlled, double-blind, randomized clinical trial of the efficacy of a chlorhexidine (10% w/v) dental coating in preventing adult caries. Participants (n = 983) were recruited from four different dental delivery systems serving four diverse communities, including one American Indian population, and were randomized to receive either chlorhexidine or a placebo treatment. The primary outcome is the net caries increment (including non-cavitated lesions) from baseline to 13 months of follow-up. A cost-effectiveness analysis also will be considered.

Discussion

This new dental treatment, if efficacious and approved for use by the Food and Drug Administration (FDA), would become a new in-office, anti-microbial agent for the prevention of adult caries in the United States.

Trial Registration Number

NCT00357877     

Multiple supernumerary teeth and odontoma in the maxilla: A case report

Most supernumerary impacted teeth are located in the anterior maxillary region. They are classified according to their form and location. Their presence may give rise to a variety of clinical problems. The detection of supernumerary teeth is best achieved by thorough clinical and radiographic examination. Their management should form part of a comprehensive treatment plan. This article presents an overview of the diagnostic problems associated with multiple supernumerary impacted teeth and includes a discussion of the classification, diagnosis, and management of this difficult clinical entity.     

Dentures for a severe class III jaw relationship

This report describes a young woman with a gross Class III skeletal pattern who had been edentulous for 10 years. She was unhappy with her appearance, mainly because her upper lip ‘fell in’. The construction of a denture with adequate labial support involved the use of a modified ‘hollow box obturator’ technique, in order to reduce the overall weight of the denture.