Stress distributions in maxillary central incisors restored with various types of post materials and designs.

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.

Vitamin A-fortified monosodium glutamate and vitamin A status: a controlled field trial.

A controlled trial of fortification of crystalline monosodium glutamate (MSG) with 810 micrograms RE vitamin A/g was undertaken in an area of endemic vitamin A deficiency in Indonesia. Powdered MSG was used to mask the yellow color of the vitamin A. Fortified MSG was marketed through ordinary channels in five villages in the program area and five nearby villages served as the control area. The product retained 84% of its potency after 4 mo and 57% after 11 mo in the marketplace. Base-line serum and breast-milk vitamin A levels were slightly higher in the control areas. Follow-up serum levels increased dramatically in program villages, 0.67 +/- 0.33 at prefortification base line to 0.92 +/- 0.33 mumol/L (p less than 0.001) at 11 mo after introduction of the fortified product. Breast-milk levels also rose, from 0.60 +/- 0.29 at base line to 0.67 +/- 0.30 mumol/L at 11 mo (p less than 0.05). Serum and breast-milk levels in control villages did not change.