Cariogenic Activity in Saliva of Korean Head and Neck Cancer Patients

The purpose of this study is to evaluate salivary flow rate, salivary pH, and cariogenic activity using unstimulated saliva of the head and neck cancer patients. Twenty three cancer patients (19 males, 4 females) who had undergone chemotherapy and radiation therapy and twenty four healthy volunteers (14 males, 10 females) as a control were included. Salivary flow rate, salivary pH, and cariogenic activity using unstimulated saliva were examined. Compared to saliva of the control group, salivary flow rate (p<0.001) and salivary pH (p<0.001) were significantly lower in head and neck cancer patients. The colony counts of Lactobacilli was higher in head and neck cancer patients (p<0.05) than in control group. These salivary factors and cariogenic activity can increase the prevalence of dental caries in head and neck cancer patients.

Four Voltage-Gated Potassium Currents in Trigeminal Root Ganglion Neurons

Various voltage-gated K+ currents were recently described in dorsal root ganglion (DRG) neurons. However, the characterization and diversity of voltage-gated K+ currents have not been well studied in trigeminal root ganglion (TRG) neurons, which are similar to the DRG neurons in terms of physiological roles and anatomy. This study was aimed to investigate the characteristics and diversity of voltage-gated K+ currents in acutely isolated TRG neurons of rat using whole cell patch clamp techniques. The first type (type I) had a rapid, transient outward current (I(A)) with the largest current size having a slow inactivation rate and a sustained delayed rectifier outward current (I(K)) that was small in size having a fast inactivation rate. The I(A) currents of this type were mostly blocked by TEA and 4-AP, K channel blockers whereas the I(K) current was inhibited by TEA but not by 4-AP. The second type had a large I(A) current with a slow inactivation rate and a medium size-sustained delayed IK current with a slow inactivation rate. In this second type (type II), the sensitivities of the I(A) or I(K) current by TEA and 4-AP were similar to those of the type I. The third type (type III) had a medium sized I(A) current with a fast inactivation rate and a large sustained I(K) current with the slow inactivation rate. In type III current, TEA decreased both I(A) and I(K) but 4-AP only blocked I(A) current. The fourth type (type IV) had a smallest I(A) with a fast inactivation rate and a large IK current with a slow inactivation rate. TEA or 4-AP similarly decreased the I(A) but the I(K) was only blocked by 4-AP. These findings suggest that at least four different voltage-gated K+ currents in biophysical and pharmacological properties exist in the TRG neurons of rats.

Response of fetal rat calvarial cells on mineral trioxide aggregate after IL-1beta stimulation / 대한치주과학회지

PURPOSE: The purpose of this study was to investigate the ability of Mineral trioxide aggregate(MTA) to support osteoclastic differentiation from fetal rat calvarial cell. METHODS: In this study, response of IL-6, RANKL, and OPG in fetal rat calvarial cells stimulated with IL-1beta on MTA was evaluated by ELISA and RT-PCR. RESULTS: The results were as follows; there was no significant difference between glass and MTA at 5days. In ELISA analysis, Glass group and MTA group showed similar IL-6 expression, Glass+IL-1beta group and MTA+IL-1beta group showed similar IL-6 expression. In RT-PCR analysis, Glass group and MTA group showed similar IL-6, RANKL, OPG mRNA expression, MTA+IL-1beta group and Glass+IL-1beta group showed 3 fold increase of IL-6 and RNAKL mRNA expression when compared with MTA group. All groups showed similar OPG mRNA expression. CONCLUSIONS: MTA does not suppress cell proliferation and increase the proinflammatory cytokine that induce osteoclastogenesis. Thus, MTA is biocompatible material that could be used in various clinical conditions.

Biological response of primary rat calvarial cell by surface treatment of Ti-8Ta-8Nb alloy / 대한치주과학회지

PURPOSE: Ti-6Al-4V alloy is widely used as an implant material because of its good biocompatibility and good mechanical property compared with commercial pure titanium. Otherwise, toxicity of aluminum and vanadium in vivo has been reported. Ti-8Ta-3Nb alloy is recently developed in the R&D Center for Ti and Special Alloys and it was reported that this alloy has high mechanical strength, no cytotoxicity and similar biocompatibility to commercial pure titanium, but many studies are needed for its clinical use. In these experiment, we carried out different surface treatment on each Ti-8Ta-3Nb alloy disks, then cultured cell on it and assessed biological response. MATERIALS AND METHODS: cpTi, Ti-6Al-4V, Ti-8Ta-3Nb alloy disks were prepared and carried out sandblasting and acid etching (SLA) or alkali-heat treatment (AH) on the Ti-8Ta-3Nb alloy disks. We cultured primary rat calvarial cells on each surface and assessed early cell attachment and proliferation by scanning electron microscopy, cell proliferation, alkaline phosphatase activity. RESULT: The rates of cell proliferation on the cpTi, Ti-8Ta-3Nb AH disks were higher than others (p<0.05) and alkaline phosphatase activity was significantly enhanced on the Ti-8Ta-3Nb AH disks (p<0.05). CONCLUSION: Most favorable cell response was shown on the Ti-8Ta-3Nb AH surfaces. It is supposed that alkali-heat treatment of the Ti-8Ta-3Nb alloy could be induced earlier bone healing and osseointegration than smooth surface.

Autogenous transplantation of tooth with complete root formation / 대한치주과학회지

PURPOSE: Autogenous transplantation of teeth can be defined as transplantation of teeth from one site to another in the same individual, involving transfer of impacted or erupted teeth into extraction sites or surgically prepared sockets". Successful autogenous transplantation of teeth depends upon a complex variety of factors. Such factors include damage to the periodontal ligament of the donor tooth, residual bone height of the recipient site, extra-oral time of tooth during surgery. Schwartz and Andreasen previously reported that autogenous transplantation of teeth with incomplete root formation demonstrated higher success rate than that of teeth with complete root formation. Gault and Mejare yielded similar rate of successful autogenous transplantation both in teeth with complete root formation and in teeth with incomplete root formation when appropriate cases were selected. This case report was aimed at the clinical and radiographic view in autogenous transplantation of teeth with complete root formation. MATERIALS AND METHODS: Patients who presented to the department of periodontics, Chonnam National University Hospital underwent autogenous transplantation of teeth. One patient had vertical root fracture in a upper right second molar and upper left third molar was transplanted. And another patient who needed orthodontic treatment had residual root due to caries on upper right first premolar. Upper right premolar was extracted and lower right second premolar was transplanted. Six months later, orthodontic force was applied. RESULTS: 7 months or 11/2 year later, each patient had clinically shallow pocket depth and normal tooth mobility. Root resorption and bone loss were not observed in radiograph and function was maintained successfully. CONCLUSION: Autogenous transplantation is considered as a predictive procedure when it is performed for the appropriate indication and when maintenance is achieved through regular radiographic taking and follow-up.