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A threshold of PTV >6 could be applied clinically for the estimation of self-drilling mini-implant root proximity.

The aim of this study was to investigate the initial stability of mini-implants when placed slanting or perpendicular to the bone surface, and to examine the effects of differences in tractional direction. Titanium mini-implants were inserted into rabbit nasal bones, slanting (60 degrees , 120 degrees ) or perpendicular (90 degrees ) to the bone surface. These implants were then loaded with a force of approximately 2 N, using a NiTi coil spring. The mobilities on the traction and non-traction sides were assessed using the Periotest device immediately after placement and after traction for two weeks. Then, the tissues with the mini-implants were resected, and the contact between the bone and the implant was examined by electron microscopy. There was a tendency for the mobilities of the mini-implants at 60 degrees and 120 degrees to be smaller than those at 90 degrees when measured before and after traction. The bone-implant contact lengths at 60 degrees were significantly longer than those at 90 degrees . There was no significant difference in the bone-implant contact ratio among the different angles. Correlations were evident between implant mobility and contact length or contact ratio. It is concluded that in clinical practice, implants inclined to the bone surface tend to have better primary stability.

This study investigated the stability of mini-screws placed in the median palate. The study included 25 patients (7 males, 18 females; mean age, 23.4 ± 5.6 years; age range, 15.0-34.5 years) who had mini-screws placed during orthodontic treatment at

LIPUS may accelerate the bone healing process after miniscrew placement in growing subjects and can reduce the latent period.

Although there have been improvements in bracket systems precoated with adhesive, removal of adhesive remnants continues to be problematic. This study compared the hardness and maintainability of precoated adhesive with other commercial adhesives. Knoop hardness values were measured after light-or chemical-induced initial curing, immersion in distilled water at 37°C for 24 h and 1,000 and 10,000 thermal cycles after 24 h. Additionally, the forces required to move brackets by 0.5 mm were measured during bracket positioning, and brackets bonded to bovine enamel were examined by field-emission scanning electron microscopy. The Knoop hardness values of the precoated adhesives were lower than those of commercial resin composite adhesives, and hardness was dependent on the amount of filler in the resin matrix. The ability to maintain the device position may depend on the resin matrix composition. Precoated adhesives with less filler and more matrix material are light curable, and remnant resin may be easily removed.

Although herbage biomass and nutrient status are widely assessed from hyperspectral measurements, certain difficulties are encountered in semiarid and arid regions with low canopy cover. This study investigated the potential of band depth approaches using partial least squares (PLS) regression to estimate herbage biomass and the concentrations of nitrogen (N) and phosphorus (P) in the Inner Mongolia grassland. Field hyperspectral measurements and plant sampling were conducted in desert and typical steppes with different fertilizer levels. The PLS analyses of typical steppe, desert steppe and combined datasets were based on canopy reflectance and first derivative reflectance (FDR) at wavelengths of 400-1000 nm, with consideration of six band depth features extracted from the red absorption region (580-740 nm). The predictive accuracy of the standard full-spectrum PLS (FS-PLS) was compared with that of the iterative stepwise elimination PLS (ISE-PLS) via the cross-validated coefficient of determination (R 2 cv ) and the ratio of prediction to standard deviation (RPD). In most of the datasets, the ISE-PLS provided better predictive results than the FS-PLS. The final models used band depth features to estimate herbage biomass (R 2 cv = 0.624-0.952, RPD = 1.506-4.539) and pasture N (R 2 cv = 0.437-0.888, RPD = 1.331-2.869) and reflectance and FDR to estimate pasture P (R 2 cv = 0.686-0.815, RPD = 1.754-2.267). The models could accurately estimate most of the grass parameters (RPD >1.5), with the exception of pasture N concentrations in the desert steppe dataset due to a range of variation that was too small. The band depth approach with ISE-PLS improved the predictive ability of the method for estimating herbage biomass and the nutrient contents of grasses in sparse grasslands.

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