Comparing the effect of a resin based sealer on crown retention for three types of cements: an in vitro study.

To determine the effect of resin based sealer on retention of casting cemented with three different luting agents. 55 extracted molar teeth were prepared with a flat occlusal surface, 20° taper and 4 mm axial height. The axial surface of each specimen was determined. The specimen were then distributed into five groups based on decreasing surface area, so each cementation group contained 11 specimens with similar mean axial surface area. A two-step, single bottle universal adhesive system (One-Step-Resinomer, Bisco) was used to seal dentin after the tooth preparation. Sealer was not used on the control specimens except for the modified-resin cement (Resinomer, Bisco) specimens that required use of adhesive with cementation. Using ceramometal (Wirobond(®), BEGO), a casting was produced for each specimen and cemented with either zinc phosphate (Harvard), glass ionomer (Vivaglass) or modified resin cement (Resinomer) with single bottle adhesive. All the castings were cemented with a force of 20 kg. Castings were thermal cycled at 5 and 55 °C for 2,500 cycles and were then removed along the path of insertion using a universal testing machine at 0.5 mm/min. A single-factor ANOVA was used with a = 0.05. The nature of failure was also recorded. The mean stress removal for non sealed zinc phosphate, sealed zinc phosphate, non sealed glass ionomer, sealed glass ionomer and modified resin cement was found to be 3.56, 1.92, 2.40, 4.26, 6.95 MPa respectively. Zinc phosphate cement remained principally on the castings when the tooth surface was treated with the sealer and was found on both the tooth and the casting when the sealer was not used. Fracture of root before dislodgement was seen in 9 of 11 specimens with modified resin cement. Resin sealer decreases the retention of the castings when used with zinc phosphate and increases it when used with glass ionomer cement. The highest mean dislodgement force was measured with modified resin cement.

Chronic Periodontitis is Associated With Cerebral Atherosclerosis -A Nationwide Study.

Introduction Chronic periodontitis and atherosclerosis share common risk factors and produce the same inflammatory markers. Many studies found a high prevalence of chronic periodontitis in patients with atherosclerosis but there is no strong evidence to support a specific association of chronic periodontitis with cerebral atherosclerosis. We aimed to study the concurrent prevalence and association of chronic periodontitis with cerebral atherosclerosis and cerebrovascular diseases among the US population. Methods We performed a cross-sectional analysis of a Nationwide Inpatient Sample with adult hospitalizations to identify the primary diagnosis of cerebrovascular diseases [acute ischemic stroke (AIS), hemorrhagic stroke (HS), and transient ischemic attack (TIA)] with concurrent cerebral atherosclerosis and chronic periodontitis. Multivariate survey logistic regression models were fitted to evaluate the linkage of chronic periodontitis with cerebral atherosclerosis and cerebrovascular diseases. Results Of total 56,499,788 hospitalizations, 0.01% had chronic periodontitis. Prevalence of chronic periodontitis was higher in 50-64 years (36.18% vs. 23.91%), males (59.19% vs. 41.06% in females), Afro-Americans (25.93% vs. 15.21%), and 0-25th percentile median-household-income-category (38.31% vs. 30.15%) compared to non-chronic periodontitis. There was significantly higher prevalence of cerebral atherosclerosis (0.71% vs. 0.41%; p<0.0001) with weak evidence of high prevalence of cerebrovascular diseases (AIS:2.21% vs. 1.97%; p=0.1563; HS:0.57% vs. 0.46%; p=0.1560) among chronic periodontitis compared to non-chronic periodontitis. In regression analysis, odds of having cerebral atherosclerosis were 2.48-folds higher in patients with chronic periodontitis compared to that without-chronic periodontitis, and cerebral atherosclerosis patients were associated with higher odds of TIA (aOR:2.40; p<0.0001), AIS (aOR:3.35; p<0.0001), and HS (aOR:1.51; p<0.0001) compared to without-cerebral atherosclerosis. No significant relationship between chronic periodontitis and cerebrovascular diseases was observed. Conclusion Although chronic periodontitis may not directly increase the risk of cerebrovascular diseases, it increases the burden of cerebrovascular diseases by evidently increasing the risk of cerebral atherosclerosis. Early identification of chronic periodontitis and atherosclerotic risk factors may help to mitigate the risk of cerebrovascular diseases.

To evaluate the validity of Recurring Esthetic Dental proportion in natural dentition.

BACKGROUND: Different proportions are described in the literature for smile designing, such as Golden proportion, Golden percentage, Preston's proportion, and recently, Recurring Esthetic Dental (RED) proportion. AIMS AND OBJECTIVES: To evaluate the existence of RED proportion in natural dentition. To determine the relative height of maxillary lateral incisor and canine occurring in natural dentition so that it can be used in any of the above proportions. MATERIALS AND METHODS: Fifteen male subjects and 15 female subjects in each of the different age groups of 18-23 years, 24-29 years and 30-35 years were selected for this study (total 90). Photographs of the subjects were taken using Nikon D200 camera with 135 mm lens and analyzed using Adobe Photoshop CS4 extended software. The height and width of maxillary central incisors, lateral incisors and canines were found out using the measuring tool provided in the software. RESULTS: Average width ratio and height ratio of maxillary lateral incisor to central incisor and maxillary canine to lateral incisor were calculated to check the existence of RED proportion in natural dentition. Average lateral incisor to central incisor height ratio for "small"- and "medium"-sized teeth was found to be 88% and for "tall"-sized teeth was found to be 84%. Average canine to lateral incisor height ratio for "small"- and "medium"-sized teeth was found to be 106% and for "tall"-sized teeth was found to be 105%. CONCLUSIONS: Within the limitations of the study, RED proportion was not seen in natural dentition.

Bruxism: a literature review.

Bruxism is a movement disorder characterized by grinding and clenching of teeth. Awake bruxism is found more in females as compared to males while sleep bruxism shows no such gender prevalence. Etiology of bruxism can be divided into three groups psychosocial factors, peripheral factors and pathophysiological factors. Treatment modalities involve occlusal correction, behavioural changes and pharmacological approach. A literature search was performed using National Library of Medicine's (NLM) Medical Subject Headings (MeSH) Database, Pubmed and Google search engines. The search term 'Bruxism' yielded 2,358 papers out of which 230 were review papers. Most of the papers selected were recently published during the period of 1996-2010 and very few of them were published before 1996.