Unilateral Mastication Evaluated Using Asymmetric Functional Tooth Units as a Risk Indicator for Hearing Loss.

BACKGROUND: Some previous studies reported hearing ability can be reduced by impaired masticatory ability, but there has been little evidence reported of an association between hearing loss and unilateral mastication. Therefore, this study aimed to investigate the relationship between unilateral mastication (UM), estimated from individual functional tooth units (FTUs), and hearing loss in a representative sample of Korean adults. METHODS: The analyzed data were obtained from 1,773 adults aged 40-89 years who participated in Korean national survey. Hearing loss was defined as a pure-tone average of >25 dB at frequencies of 0.5, 1, 2, and 4 kHz in either ear. In each subject, UM was calculated as the difference in the sums of the FTU scores, which is an index of posterior tooth occlusion, on the two sides of the oral cavity. The scores were used to classify the UM into low, moderate, and high. The adjusted odds ratios (aORs) and their 95% confidence intervals (CIs) were calculated in multivariable logistic regression analyses. RESULTS: When controlling for sociodemographic factors, the aOR for hearing loss was 3.12 (95% CI, 1.21-8.03) for high UM relative to low UM. This association remained in a fully-adjusted model containing factors related to noise exposure (aOR 2.88; 95% CI, 1.12-7.46). CONCLUSION: Adults with high UM as measured using FTUs showed a higher occurrence of hearing loss than those with low UM.

Detection of residual resin-based orthodontic adhesive based on light-induced fluorescence.

INTRODUCTION: This study evaluated the fluorescence of orthodontic adhesives using quantitative light-induced fluorescence-digital (QLF-D) images, and compared differences in the color characteristics of the fluorescence between adhesive and the adjacent tooth with that under white-light illumination in specimens containing residual adhesive of various thicknesses. METHODS: Disc-shaped adhesive samples and samples comprising adhesive attached to extracted human teeth were prepared using Transbond XT, Blugloo, and Enlight, and they were ground to thicknesses ranging from 800 to 20 µm. Fluorescence and white-light images of the two types of specimens were taken with a QLF-D system. The color parameters for the fluorescence from the discs and the color difference (ΔE) between residual adhesive and the adjacent tooth were quantified in images using the CIE L*a*b* system. RESULTS: The fluorescence color values of the discs differed significantly among the three adhesive products (P < 0.05). The ΔE values in fluorescence (ΔEF) and white-light (ΔEW) images for all three adhesives were lower for thinner residual adhesive specimens. The thickness of the adhesive could be perceived over a range of 50-100 µm for fluorescence images and 400-800 µm for white-light images (ΔE > 3.3). ΔEF was significantly larger than ΔEW for all of the residual adhesives, Blugloo specimens thicker than 100 µm, and Transbond XT and Enlight specimens thicker than 50 µm (P < 0.05). CONCLUSIONS: Detecting and analyzing fluorescence signals can improve the ability to detect residual adhesive on a tooth and also provide thickness information.

Management of Pediatric Patients Presenting with Acute Abdomen Accompanying Dilatation of the Common Bile Duct.

PURPOSE: The aim of this study was to describe our treatment experiences with patients who had acute abdomen (AA) with common bile duct (CBD) dilatation. METHODS: The treatment outcomes in children with AA and CBD dilatation were retrospectively reviewed. According to the shape of the intrahepatic bile ducts on ultrasonography (US), the origin of the pain was estimated as choledochal cyst (CC) complication or choledocholithiasis in normal CBD. Patients with complicated CC underwent surgery, and patients with choledocholithiasis in a normal appearing CBD underwent symptomatic treatment initially. RESULTS: Of the 34 patients, 30 (88.2%) were female. The mean age of the patients was 6.4±4.9 (range, 0.8-17) years. Seventeen (50.0%) patients had CBD stones and 17 (50.0%) did not. Surgical treatment was performed in 20 (58.8%) patients, 2 of whom underwent preoperative stone removal with endoscopic retrograde cholangiopancreatography and an operation. Conservative treatment was applied in 12 (35.3%) patients (8 with and 4 without stones), 1 of whom developed symptom relapse and underwent an operation. Among the 8 patients with CBD stones, 4 (4/17, 23.5%) had complete resolution of the stones and recovery of the CBD diameter after conservative treatment. US findings of patients with stone showed a fusiform or cylindrical shape of the CBD in 14 (82.4%) patients. CONCLUSION: The presence of stones in the distal CBD and the US features of CBD dilatation may be helpful to diagnose and treat the causes of biliary dilatation. Conservative treatment can be considered as initial therapy in patients with uncomplicated CBD dilatation with stone.

Differences in the intensity of light-induced fluorescence emitted by resin composites.

BACKGROUND: The aims of this study were to compare the intensities of fluorescence emitted by different resin composites as detected using quantitative light-induced fluorescence (QLF) technology, and to compare the fluorescence intensity contrast with the color contrast between a restored composite and the adjacent region of the tooth. METHODS: Six brands of light-cured resin composites (shade A2) were investigated. The composites were used to prepare composite discs, and fill holes that had been prepared in extracted human teeth. White-light and fluorescence images of all specimens were obtained using a fluorescence camera based on QLF technology (QLF-D) and converted into 8-bit grayscale images. The fluorescence intensity of the discs as well as the fluorescence intensity contrast and the color contrast between the composite restoration and adjacent tooth region were calculated as grayscale levels. RESULTS: The grayscale levels for the composite discs differed significantly with the brand (p<0.001): DenFil (10.84±0.35, mean±SD), Filtek Z350 (58.28±1.37), Premisa (156.94±1.58), Grandio (177.20±0.81), Charisma (207.05±0.77), and Gradia direct posterior (211.52±1.66). The difference in grayscale levels between a resin restoration and the adjacent tooth was significantly greater in fluorescence images for each brand than in white-light images, except for the Filtek Z350 (p<0.05). However, the Filtek Z350 restoration was distinguishable from the adjacent tooth in a fluorescence image. CONCLUSIONS: The intensities of fluorescence detected from the resin composites varied. The differences between the composite and adjacent tooth were greater for the fluorescence intensity contrast than for the colors observed in the white-light images.