Effect of finish line design on stress distribution in bilayer and monolithic zirconia crowns: a three‐dimensional finite element analysis study

This study evaluated the influence of different finish line designs and abutment materials on the stress distribution of bilayer and monolithic zirconia crowns using three‐dimensional finite element analysis (FEA). Three‐dimensional models of two types of zirconia premolars – a yttria‐stabilized zirconia framework with veneering ceramic and a monolithic zirconia ceramic – were used in the analysis. Cylindrical models with the finish line design of the crown abutments were prepared with three types of margin curvature radius (CR): CR = 0 (CR0; shoulder margin), CR = 0.5 (CR0.5; rounded shoulder margin), and CR = 1.0 (CR1.0; deep chamfer margin). Two abutment materials (dentin and brass) were analyzed. In the FEA model, 1 N was loaded perpendicular to the occlusal surface at the center of the crown, and linear static analysis was performed. For all crowns, stress was localized to the occlusal loading area as well as to the axial walls of the proximal region. The lowest maximum principal stress values were observed when the dentin abutment with CR0.5 was used under a monolithic zirconia crown. These results suggest that the rounded shoulder margin and deep chamfer margin, in combination with a monolithic zirconia crown, potentially have optimal geometry to minimize occlusal stress.     

Association of periodontal status with occlusal force and food acceptability in 70‐year‐old adults: from SONIC Study

This cross‐sectional study aimed to investigate the association of periodontal status with occlusal force and food acceptability. We hypothesised that mastication deteriorated with reduced periodontal support, even when posterior occlusal contacts with natural teeth were maintained and the patients remained clinically asymptomatic. Participants were 482 independently living 69‐71‐year‐olds, classified as Eichner's group A, having no mobile teeth and no periodontal symptoms. The periodontal probing depth (PPD) and restoration status of each tooth were examined. Occlusal force in the intercuspal position was measured with pressure‐sensitive films. Food acceptability was evaluated from the difficulty experienced in chewing apples, grilled beef, and hard rice crackers. Multivariate regression analysis was performed to investigate the association of periodontal status with occlusal force and food acceptability. A P‐value of <0·05 was considered statistically significant. Multiple linear regression analysis showed that occlusal force had significant negative associations with maximal PPD (standardised partial regression coefficient (β) = ?0·121) after controlling for gender, handgrip strength, number of teeth, and percentage of restored teeth. Approximately 15% of participants were included in the compromised food acceptability group. Logistic regression analyses showed that compromised food acceptability was significantly associated with PPD, after controlling for gender, number of teeth, and percentage of restored teeth. Periodontal probing depth (PPD) was significantly correlated with occlusal force and self‐rated food acceptability after controlling for the possible confounding factors in septuagenarians, even those with complete posterior occlusal contacts and no tooth mobility.     

Factors associated with the publication outcomes of paediatric proceedings presented at 2010‐2016 the International Associations for Dental Research annual meetings

The International Associations for Dental Research (IADR) annual meeting is one of the most important dental meetings throughout the world, and researches about paediatric dentistry presented in this platform are often used to guide clinical work. To evaluate the publication outcomes of oral and poster paediatric proceedings, which were accepted by the International Associations for Dental Research (IADR), annual meetings from 2010 to 2016 and to analyse the possible factors influencing an abstract's progression to publication. Oral and poster abstracts were retrieved from the official website of IADR (2010‐2016). Searching for subsequent publications was conducted in PubMed and Google Scholar (up to March 2019). Two authors independently selected studies, collected, and analysed data. A total of 1396 abstracts were identified, including 275 oral presentations and 1121 poster presentations. Finally, 606 were published in peer‐reviewed journals, with a publication rate of 43.41%. Abstracts were published earlier if it is from Europe, well funded, presented orally, or with large sample size. The high publication rate of the IADR proceedings supported the impact of IADR annual meetings on paediatric dentistry in the last 10 years.