Effect of fiber posts on stress distribution of endodontically treated upper premolars : finite element analysis

By means of a finite element method (FEM), the present study evaluated the effect of fiber post (FP) placement on the stress distribution occurring in endodontically treated upper first premolars (UFPs) with mesial–occlusal–distal (MOD) nanohybrid composite restorations under subcritical static load. FEM models were created to simulate four different clinical situations involving endodontically treated UFPs with MOD cavities restored with one of the following: composite resin; composite and one FP in the palatal root; composite and one FP in the buccal root; or composite and two FPs. As control, the model of an intact UFP was included. A simulated load of 150 N was applied. Stress distribution was observed on each model surface, on the mid buccal–palatal plane, and on two horizontal planes (at cervical and root-furcation levels); the maximum Von Mises stress values were calculated. All analyses were replicated three times, using the mechanical parameters from three different nanohybrid resin composite restorative materials. In the presence of FPs, the maximum stress values recorded on dentin (in cervical and root-furcation areas) appeared slightly reduced, compared to the endodontically treated tooth restored with no post; in the same areas, the overall Von Mises maps revealed more favorable stress distributions. FPs in maxillary premolars with MOD cavities can lead to a positive redistribution of potentially dangerous stress concentrations away from the cervical and the root-furcation dentin

Prevalence of dental caries and oral hygiene habits in patients with Crohn's disease living in urban and rural regions of southern Poland

Patients with Crohn’s disease (CD) prefer carbohydrates and foods, which easy to digest, both risk factors of caries disease. The aim of this study was to evaluate the dental caries prevalence and oral hygiene habits in CD patients who live in urban and rural areas of the southern part of Poland in comparison to controls. Seventy one adult patients with CD and 61 age – and sex – matched volunteers were enrolled; 52% of patients were living in urban areas, 48% in rural regions. We studied: findings on clinical examination, calculation of BMI, blood hemoglobin and serum CRP levels, oral examination according to the WHO recommendations, with assessment of oral hygiene habits, dental history, visits to dentists. Presence of decayed (D), missing (M), filled teeth (F) were assessed, and the “Decayed, Missing, and Filled Teeth Index” (DMF-T) was calculated. Statistical methods included non-parametric tests and Spearman correlation coefficient estimation. Dental caries assessed by DMF-T index was higher in CD patients compared to controls. DMF-T was similar in patients from urban and rural areas (14.2±4.7 vs 15.4±2.1, respectively). M and F scores were comparable in both groups, but D score was higher in CD patients (p<0.01). No correlation was found between DMF-T index and place of living. Patients from rural areas less frequently used tooth brushing (68% vs 57%, p<0.05) and dental floss (11% vs 5%, p<0.05). Patients from urban areas visited dentists more frequently than those from rural regions. The prevalence of dental caries in the middle aged CD patients living in the southern region of Poland is higher in comparison to healthy controls. The prevalence of caries disease and oral hygiene habits in CD patients is comparable between patients living in urban areas and in rural regions

Effect of composite core materials on fracture resistance of endodontically treated teeth : a systematic review and meta-analysis of in vitro studies

Various material properties are involved in the success of endodontically treated restorations. At present, restorative composites are commonly employed as core build-up materials. This study aimed to systematically review the literature to assess the effect of using composite core materials on the in vitro fracture of endodontically treated teeth. Two different reviewers screened the literature, up to June 2021, in five distinct electronic databases: PubMed (MedLine), Scopus, Scielo, ISI Web of Science, and EMBASE. Only in vitro studies reporting the effect of the use of composite core materials on the fracture resistance of endodontically treated teeth were included. A meta-analysis was carried out using a software program (Review Manager v5.4.1; The Cochrane Collaboration, Copenhagen, Denmark). The risk of bias in each study was assessed following the parameters of another systematic review. A total of 5016 relevant papers were retrieved from all databases. After assessing the title and abstract, five publications remained for qualitative analysis. From these, only three studies remained for meta-analysis. The fracture strength of endodontically treated teeth where a core build-up composite was used was statistically significantly higher than the control (p = 0.04). Most of the analyses showed a high heterogenicity. The in vitro evidence suggests that the composite core build-up with higher filler content tended to improve the fracture resistance of the endodontically treated teeth, in comparison with conventional composite resins. This research received no external funding. Considering that this systematic review was only carried out on in vitro papers, registration was not performed. Furthermore, there were no identified clinical studies assessing core build-up materials; therefore, more well-designed research on these materials is needed