Reference points suitable for evaluation of the additional arch length required for leveling the curve of Spee.

OBJECTIVE: The additional arch length required for leveling (AALL) the curve of Spee (COS) can be estimated by subtracting the two-dimensional (2D) arch circumference, which is the projection of the three-dimensional (3D) arch circumference onto the occlusal plane, from the 3D arch circumference, which represents the arch length after leveling the COS. The purpose of this study was to determine whether the cusp tips or proximal maximum convexities are more appropriate reference points for estimating the AALL. METHODS: Sixteen model setups of the mandibular arch with COS depths ranging from 0 mm to 4.7 mm were constructed using digital simulation. Arch circumferences in 2D and 3D were measured from the cusp tips and proximal maximum convexities and used to calculate the AALL. The values obtained using the two reference points were compared with the paired t-test. RESULTS: Although the 3D arch circumference should be constant regardless of the COS depth, it decreased by 3.8 mm in cusp tip measurements and by 0.4 mm in proximal maximum convexity measurements as the COS deepened to 4.7 mm. AALL values calculated using the cusp tips as reference points were significantly smaller than those calculated using the proximal maximum convexities (p = 0.002). CONCLUSIONS: The AALL is underestimated when the cusp tips are used as measurement reference points; the AALL can be measured more accurately using the proximal maximum convexities.

Comparative evaluation of nutritional compositions between transgenic rice harboring the CaMsrB2 gene and the conventional counterpart.

As a part of a safety assessment of new transgenic crops, compositional equivalence studies between transgenic crops with non-transgenic comparators are almost universally required. This study was conducted to compare nutritional profiles of proximate composition, and fatty acid, amino acid, mineral, and vitamin contents, and anti-nutrients, between transgenic drought-tolerant Agb0103 rice harboring the pepper methionine sulfoxide reductase B2 gene CaMsrB2 and the parental rice cultivar, 'Ilmi' as a non-transgenic control. Both transgenic and non-transgenic rice were grown and harvested in 2 different locations. Proximate compositions of moisture, starch, protein, lipid, and ash content of Agb0103 rice were similar to parental non-transgenic rice. There were no differences between transgenic and non-transgenic rice with respect to the whole nutritional composition, except for minor locality differences for a few nutritional components. Agb0103 rice with improved resistance to drought is nutritionally equivalent to the parental rice cultivar.