ABSTRACT
Objectives: This study aims to identify the relationship between dietary intakes of β-carotene with riskof oral cancer. Methods: A hospital-based, case-control study was conducted on 306 Malaysians whoseek treatment at participating centres/hospitals. Subjects selected from the Malaysian Oral Cancer Dataand Tissue Banking System (MOCDTBS) consisted of 153 cases and 153 controls that were matchedfor gender, age (±5 years) and ethnicity. Food consumption was measured using Food FrequencyQuestionnaire (FFQ). NutrieMart Version 2.0.0 software was used to estimate daily nutrient of eachsubject from the FFQ. Logistic Regression analysis was conducted to compute the odds ratio (OR) forintakes of β-carotene and oral cancer risk. Results: Intake of β-carotene was found to be not associatedwith risk of oral cancer (OR 0.83, 95%CI: 0.42-1.66, p>0.05). Conclusion: No significant associationwas found between dietary intakes of β-carotene with oral cancer risk in this study population.
ABSTRACT
Different dental post designs and materials affect the stability of restoration of a tooth. This study aimed to analyse and compare the stability of two shapes of dental posts (parallel-sided and tapered) made of five different materials (titanium, zirconia, carbon fibre and glass fibre) by investigating their stress transfer through the finite element (FE) method. Ten three-dimensional (3D) FE models of a maxillary central incisor restored with two different designs and five different materials were constructed. An oblique loading of 100 N was applied to each 3D model. Analyses along the centre of the post, the crown-cement/core and the post-cement/dentine interfaces were computed, and the means were calculated. One-way ANOVAs followed by post hoc tests were used to evaluate the effectiveness of the post materials and designs (p=0.05). For post designs, the tapered posts introduced significantly higher stress compared with the parallel-sided post (p<0.05), especially along the centre of the post. Of the materials, the highest level of stress was found for stainless steel, followed by zirconia, titanium, glass fibre and carbon fibre posts (p<0.05). The carbon and glass fibre posts reduced the stress distribution at the middle and apical part of the posts compared with the stainless steel, zirconia and titanium posts. The opposite results were observed at the crown-cement/core interface.
