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The bionator is one of the most commonly used functional appliances in treating Angle Class II division 1 malocclusions. However, the original type of bionator often causes lower incisor flaring and is limited in cases with mild crowding. There is little published literature on treating Angle Class II division 2 malocclusions using bionators. Our group suggested some modifications to the original-type bionator, including addition of an anterior resin cap, upper and lower labial bows, an expansion screw and a posterior resin wedge, to attempt to overcome limitations of the original design. This article shows our results on two male patients, one with an Angle Class II division 1 malocclusion with a large overjet and the other with an Angle Class II division 2 malocclusion. The treatment was completed using a newly modified bionator with no other fixed appliance and resulted in a decrease in facial convexity, a reduced overjet and overbite, ideal interincisal relationships, and a harmonious profile.

Background/PurposeAssessing periodontal conditions has always been a concern for dental researchers. In this study, we evaluated the potential of a natural frequency (NF) analysis to detect the health status of natural human canine teeth.Materials and methodsThree-dimensional finite element models of the human maxillary canine were constructed. NF values of the canine model were calculated with one-, two- and three-sided vertical bone loss.ResultsBy simulating a modal testing experiment, the NF value for a healthy canine was found to be 2581 Hz. As the bone level was lowered, a strong linear relationship between the frequency and attachment level was demonstrated in all three models. Results from this study demonstrated that the change in the NF was < 12% in canines with a one-sided defect when the bone level varied by 10 mm from the cementoenamel junction. However, when a three-sided bony defect was simulated, the change in NF ranged from 20% to 60%.ConclusionThis study demonstrates that the NF of the human canine decreases with various degrees of periodontal bone height loss.

Background/purpose: The aim of this study was to examine the effects of the time period between tooth extraction and the freezing procedure on pulp cells in frozen intact teeth of rats. Material and methods: In total, 120 incisors from 30 rats were extracted and kept in transportation solution for 0 hour, 12 hours, and 24 hours. The tested teeth were divided into 2 experimental groups, where the extracted incisors were first frozen in a magnetic-programmed freezer (PF) or a traditional −20°C freezer (TF). The tested teeth were then stored at −150°C for 7 days. Incisors extracted from the opposite side of the same rat were treated as the non-frozen control. After thawing, the pulp was extracted and dissected. Hematoxylin and eosin staining was performed to observe the cell distributions. Cell densities in the odontoblast region and cell-rich zone were calculated using an optical microscope. Results: When samples were immediately frozen after extraction, the cell density of odontoblastic cells was higher in the PF group compared with analogs which were frozen in the −20°C freezer (P

Background Grape seeds extract (GSE) is a famous health food supplement for its antioxidant property. Different concentrations of GSE may have different impacts on cellular oxidative/reduction homeostasis. Antiproliferative effect of GSE has been reported in many cancers but rarely in oral cancer. Methods The aim of this study is to examine the antioral cancer effects of different concentrations of GSE in terms of cell viability, apoptosis, reactive oxygen species (ROS), mitochondrial function, and DNA damage. Results High concentrations (50–400 μg/ml) of GSE dose-responsively inhibited proliferation of oral cancer Ca9-22 cells but low concentrations (1–10 μg/ml) of GSE showed a mild effect in a MTS assay. For apoptosis analyses, subG1 population and annexin V intensity in high concentrations of GSE-treated Ca9-22 cells was increased but less so at low concentrations. ROS generation and mitochondrial depolarization increased dose-responsively at high concentrations but showed minor changes at low concentrations of GSE in Ca9-22 cells. Additionally, high concentrations of GSE dose-responsively induced more γH2AX-based DNA damage than low concentrations. Conclusions Differential concentrations of GSE may have a differentially antiproliferative function against oral cancer cells via differential apoptosis, oxidative stress and DNA damage.