PURPOSE: This study was performed to examine the effects of image filter on observer performance by counting the number of holes at each wedge step on a radiographic image. MATERIALS AND METHODS: An aluminum step wedge with 11 steps ranged in thickness from 1.5 mm to 16.5 mm in 1.5 mm increments was fabricated for this study. Each step had 10 notched holes with 1.0 mm diameter on the bottom of the step wedge which were ranged in depths from 0.1 mm to 1.0 mm in 0.1 mm increments. Digital radiographic raw images of the aluminum step wedge were acquired by using CCD intraoral sensor. The images were processed using several types of noise reduction filters and kernel sizes. Three observers counted the number of holes which could be discriminated on each step. The data were analyzed by ANOVA. RESULTS: The number of holes at each step was decreased as the thickness of step was increased. The number of holes at each step on the raw images was significantly higher than that on the processed images. The number of holes was different according to the types and kernel sizes of the image filters. CONCLUSION: The types and kernel sizes of image filters on observer performance were important, therefore, they should be standardized for commercial digital imaging systems.
Aluminum ; Noise ; Radiographic Image Enhancement ; Radiography, Dental ; Task Performance and Analysis

Clinical remounting of complete denture is performed to refine occlusal harmony in maxillo-mandibular relation. It has been reported that patients who used adjusted dentures with clinical remounting felt less complications such as pain and discomfort in mastication. The purpose of this study was to assess effects of clinical remounting with case series. Seven patients with existing complete prosthesis were included. Clinical remounting procedure was done through interocclusal relation recording. In addition, occlusal force was measured with pressure indicating sensor and occlusal contact areas were evaluated with photo occlusion analysis. Occlusal contact areas of prosthesis were enlarged, while bite pressure was not increased. Hit and slide phenomenon of prosthesis was reduced concurrently. Clinical remounting procedure improved denture stability and increased occlusal contact area. Therefore, clinical remounting should be considered.

We investigated the action of NOS inhibitors on NOS in rats. Both of nitric oxide synthase inhibitors, NG-monomethyl-L-arginine (L-NMMA, 3 micrometer) or NG-nitro-L-arginine methylester (L-NAME, 30 micrometer), augmented phenylephrine (PE, 10-7 M)-induced contraction which was inhibited by acetylcholine (ACh) in rat thoracic aorta. This augmentation by L-NAME or L-NMMA was attenuated with the treatment of NO precursor, arginine. ACh, however, decreased the augmentation induced by L-NMMA, but not by L-NAME. Superoxide dismutase (SOD, 50 u/ml) potentiated an inhibitory effect of ACh on the PE (10-7 M)-induced contraction. It has been known that platelet activating factor itself induces iNOS. Platelet activating factor (PAF, 10-7 M) inhibited PE (10-7 M)-induced contraction. Pretreatment with L-NMMA (30 mM) or L-NAME (30 mM) significantly blocked the inhibitory action of PAF on PE-induced contraction. L-NMMA (100 mM) or L-NAME (100 mM) reduced nerve conduction velocity (NCV) relevant to nNOS in rat sciatic nerve. ACh attenuated the reduction of NCV by L-NMMA-, but not by L-NAME-induced reduction of NCV. These results suggest that L-NMMA and/or L-NAME have different action on three types of NOS in rats.
Acetylcholine ; Animals ; Aorta, Thoracic ; Arginine ; Neural Conduction ; NG-Nitroarginine Methyl Ester ; Nitric Oxide Synthase* ; Nitric Oxide* ; Nitroarginine ; omega-N-Methylarginine ; Phenylephrine ; Platelet Activating Factor ; Rats* ; Sciatic Nerve ; Superoxide Dismutase