An observational study of hydrodynamic impact on water mass transport due to tidal power generation.

The world's largest Sihwa Tidal Power Plant (TPP), located on the west coast of Korea, was built in 2011 for the purpose of improving water quality and producing renewable energy. After several years of actual operation, most of the original purpose was achieved, but unexpected coastal environmental changes such as tidal flat damage and sediment accumulation also occurred. In this study, in order to understand the causes of these environmental changes, field observations were conducted near TPP, and spatial and temporal variability of flow structure and water exchange process were investigated. Three-dimensional velocity data were collected along the closed line surrounding the outside of the TPP for 11 h during spring tide and analyzed according to two discharge phases: power generation phase (PGP) and drainage phase (DP). The results show that the depth-averaged maximum current velocity was more than three times greater at DP than at PGP. Jet-like flow during DP caused very high horizontal shear, whereas vertical shear was relatively weak, indicating that the horizontal and vertical flow structures were very different. The most notable result is that the mass transport patterns between PGP and DP are significantly different, i.e., during PGP, mass transport is dominated on the left side of the TPP, whereas during DP, it occurs at the front of the TPP. This means that there is a strong spatiotemporal asymmetry between the inflow from the downstream (outside of the TPP) during PGP and the outflow from the upstream (inside of the TPP) during DP. These asymmetric processes can have a significant impact on the material exchange and sediment transport near the TPP. Since observational studies on TPP are extremely rare, this study is expected to contribute to future TPP related research, such as numerical modeling.

In Vitro Red Fluorescence as an Indicator of Caries Lesion Activity.

This in vitro study examined the utility of comparing red fluorescence between active and inactive caries lesions and investigated whether changes in red fluorescence and fluorescence loss are influenced by lesion activity following remineralization. Sixty-two noncavitated smooth surface caries lesions on extracted human teeth were classified into active or inactive lesions using the Nyvad system prior to a 12-day pH-cycling procedure. Quantitative light-induced fluorescence-digital images were used to measure fluorescence parameters before and after pH cycling. At baseline, the intensity (ΔR) and area (AΔR) of red fluorescence were 1.5- and 2.2-fold higher in active lesions than in inactive lesions (p<0.05). The ratio of AΔR to lesion area was associated with classification of active lesions (odds ratio = 1.031; 95% confidence interval = 1.005-1.058). After pH cycling, the active lesions showed about 2- and 8-fold greater reductions in the median values of AΔR and fluorescence loss related to lesion volume (ΔQ) compared with inactive lesions (p<0.05). In conclusion, red fluorescence differs depending on lesion activity, and the red fluorescence area and lesion volume change following remineralization. The results suggest that measuring red fluorescence may be a useful way of objectively evaluating lesion activity of smooth surface lesions.

Larval species composition and genetic structures of Carposina sasakii, Grapholita dimorpha, and Grapholita molesta from Korea.

Rapid determination of the larval species composition and understanding of their genetic structure is important to establish the appropriate management system for multiple species infesting in fruits. We established accurate and rapid diagnostic methods based on multiplex polymerase chain reaction (PCR) diagnostic techniques to discriminate the three major lepidopteran species in orchard, Carposina sasakii, Grapholita dimorpha, and Grapholita molesta. Each species was identified by amplifying species-specific PCR products (375 bp for C. sasakii, 125 and 234 bp for G. dimorpha, and 125 bp for G. molesta). Based on species composition analysis from six types of infested fruits, G. dimorpha constituted the highest proportion (47.8%), followed by 35.2 and 13.5% for G. molesta and C. sasakii, respectively. Interestingly, high prevalence was found in G. dimorpha and G. molesta for plum and peach, respectively. Based on genetic diversity analysis, the three insect species exhibited moderate or high haplotype diversity and low nucleotide diversity, ranging from 0.319 to 0.699 and 0.0006 to 0.0045, respectively. Demographic expansion was not detected according to either a neutrality test or mismatch distribution analysis. Moreover, no significant genetic structure corresponding to province, host plant, fruit type, or collection period was observed. These results suggest that the population of each species would have high dispersal ability following fruit-generating periods via intrinsic host adaptation ability regardless of the spatial and temporal conditions. Determination of larval composition on fruit is valuable for establishing appropriate management systems that take the species into consideration; additionally, population genetic approaches can be utilized to understand the effects of environmental factors (province, host fruit, fruit type, etc.) on population structures.

Evaluation of penetration effect of resin infiltrant using optical coherence tomography.

OBJECTIVE: The aims of this in vitro study were to investigate whether optical coherence tomography (OCT) could analyze infiltration of resin infiltrant (RI) into early dental caries (EC), and to confirm the correlation between the results of OCT and confocal laser scanning microscopy (CLSM) for evaluation of RI infiltration into EC. METHODS: Sound bovine permanent teeth were used to produce sixty specimens by making two windows on the teeth. Each 20 specimens were demineralized for 20, 30, and 40 days, and the RI was treated on one of the windows. As a result, the images of the fifty-two specimens were taken by OCT and CLSM. The demineralized lesion depth (LDOCT and LDCLSM) and the infiltrated depth of RI into lesion (IDOCT and IDCLSM) obtained from the OCT and the CLSM were analyzed. The correlations between the LDOCT and the LDCLSM, and between the IDOCT and the IDCLSM, were analyzed by Pearson correlation and intra-class correlation. Also, Bland-Altman plot was constructed to assess the agreement between the IDOCT and the IDCLSM, and the IDOCT divided by refractive index of RI and the IDCLSM. RESULTS: The Pearson correlation coefficient and intra-class correlation of 0.75 and 0.83 (95% CI: 0.71-0.91) respectively were confirmed between the LDOCT and the LDCLSM (p<0.001), and 0.59 and 0.71 (95% CI: 0.50-0.84) respectively were observed between the IDOCT and the IDCLSM (p<0.001). The lower bias was confirmed in Bland-Altman plot between adjusted IDOCT and the IDCLSM than between the IDOCT and the IDCLSM. CONCLUSION: The OCT was the promising quantitative evaluation method for RI penetrated into EC. CLINICAL SIGNIFICANCE: The OCT would be used as a nondestructive and real-time evaluation method for RI penetrated into EC on clinical procedure.

White matter microstructural changes in pure Alzheimer's disease and subcortical vascular dementia.

BACKGROUND AND PURPOSE: Recent studies have demonstrated that Alzheimer's disease (AD) and subcortical vascular dementia (SVaD) have white matter (WM) microstructural changes. However, previous studies on AD and SVaD rarely eliminated the confounding effects of patients with mixed Alzheimer's and cerebrovascular disease pathologies. Therefore, our aim was to evaluate the divergent topography of WM microstructural changes in patients with pure AD and SVaD. METHODS: Patients who were clinically diagnosed with AD and SVaD were prospectively recruited. Forty AD patients who were Pittsburgh compound B (PiB) positive [PiB(+) AD] without WM hyperintensities and 32 SVaD patients who were PiB negative [PiB(-) SVaD] were chosen. Fifty-six cognitively normal individuals were also recruited (NC). Tract-based spatial statistics of diffuse tensor imaging were used to compare patterns of fractional anisotropy (FA) and mean diffusivity (MD). RESULTS: Compared with the NC group, the PiB(+) AD group showed decreased FA in the bilateral frontal, temporal and parietal WM regions and the genu and splenium of the corpus callosum as well as increased MD in the left frontal and temporal WM region. PiB(-) SVaD patients showed decreased FA and increased MD in all WM regions. Direct comparison between PiB(+) AD and PiB(-) SVaD groups showed that the PiB(-) SVaD group had decreased FA across all WM regions and increased MD in all WM regions except occipital regions. CONCLUSION: Our findings suggest that pure AD and pure SVaD have divergent topography of WM microstructural changes including normal appearing WM.

Effect of nano-carbonate apatite to prevent re-stain after dental bleaching in vitro.

OBJECTIVES: This study examined the effect of nano-carbonate apatite (n-CAP) to prevent re-staining and the change of enamel surface after dental bleaching in vitro. METHODS: Twenty-four bovine specimens were bleached for 2 weeks with 10% carbamide peroxide (CP). After bleaching, the specimens were divided into the following four groups: distilled and deionized water (DDW, negative control), 10% n-CAP, NaF (positive control) and casein phosphopeptide-amorphous calcium phosphate (CPP-ACP, positive control). Each group was subjected to pH cycling for 7 days. The specimens were treated for 4 min 3 times per day and re-staining was induced naturally by artificial saliva in the remineralization process. After pH cycling, the changes in colour were evaluated with spectrophotometry and scanning electron microscopy (SEM). The difference in colour between before and after pH cycling was evaluated using an ANOVA and Tukey test. RESULTS: After pH cycling, the colour difference of n-CAP group was significantly lower than that of the DDW and CPP-ACP groups (p<0.05). SEM showed that n-CAP particles were deposited regularly on the damaged surface compared to the other groups. CONCLUSION: 10% n-CAP could significantly maintain the initial colour and protect the damaged enamel structure after bleaching.

The addition of nano-sized hydroxyapatite to a sports drink to inhibit dental erosion: in vitro study using bovine enamel.

OBJECTIVES: This study examined the dental erosion and demineralization potential of a sports drink containing nano-sized hydroxyapatite (nano-HA) as an additive. METHODS: The experimental solutions were Powerade (PA) alone and PA with 0.05%, 0.10%, and 0.25% nano-HA. The pH, titratable acidity, and calcium and phosphate content of each solution were analysed, and the degree of saturation with respect to the dental enamel (DS(En)) was obtained. Twelve sound bovine enamel specimens for each group were treated in accordance with the pH-cycling schedule which had 60min treatment with experimental solution per day for 7 days. The erosion potential was determined from the changes in surface micro hardness (SMH), the depths of erosion and demineralized layer using confocal laser scanning microscopy (CLSM), and the morphological changes to the tooth surface were examined with scanning electron microscopy (SEM) after pH-cycling. RESULTS: pH and DS(En) increased with increasing nano-HA concentration in the drinks, whereas the titratable acidity decreased. There were significant differences in the SMH between the PA alone and >0.10% nano-HA groups (p<0.001). Although the PA alone group showed a pronounced erosion depth, CLSM showed no erosion depth in 0.25% nano-HA group. SEM showed an intact surface with increasing nano-HA concentration in the drinks. In conclusion, dental erosion was effectively prevented with increase of adding concentration of nano-HA, and a sports drink containing 0.25% nano-HA might prevent dental erosion.

Subjective food intake ability in relation to the Mixing Ability Index in Korean adults.

This study examined the association between the subjective food intake ability (FIA) using a questionnaire with 30 types of foods and the objective Mixing Ability Index (MAI) using a two-coloured wax cube. A total of 147 subjects (32 males, 115 females, mean age: 54.9 +/- 20.7) were enrolled in this study. The FIA for 30 food types and the key food intake ability (KFIA) for five key food types were obtained using a self-assessed questionnaire to evaluate the subjective chewing ability. The objective chewing ability was evaluated by asking the subjects to chew a wax cube for 10 strokes. The MAI was calculated by image analysis of the chewed wax cube. The Pearson's correlation between the subjective FIA and objective MAI was analysed according to age and number of post-canine teeth lost. The FIA for the 30 foods and five key food types showed a moderate correlation with the MAI (r = 0.51, 0.55, respectively, P < 0.01). The KFIA of the denture wearing group (r = 0.44, P < 0.01) and over 60-year-old group (r = 0.49, P < 0.01) showed a significantly higher correlation with the MAI than the other groups. In conclusion, there was a moderate correlation between the subjective FIA and objective MAI in Korean adults.

Application of fluoride iontophoresis to improve remineralization.

Iontophoresis is generally used to maximize the therapeutic action of drugs in medicine. This technique can be used to improve the remineralization effect of topical fluoride applications in dentistry. The aim of this study was to compare the remineralization effect of fluoride iontophoresis (FI) with the conventional fluoride application (CFA) method in vitro. Sixty bovine enamel specimens were divided into three groups: no fluoride treatment, CFA and FI. Fluoride was applied to the demineralized specimens for 4 min in each experimental group. The types of fluoride system used for application were 1.23% acidulated phosphate fluoride gel (12 300 p.p.m. F, pH 3.5) and 2% sodium fluoride solution (9050 p.p.m. F, pH 7) in the experimental groups. All the specimens were then placed in a remineralizing solution for 24 h. This cycle was repeated five times. An iontophoresis device (0.4 mA, 12 V) was used in the FI groups. The efficacy of this technique was evaluated by measuring changes in the surface microhardness and lesion depth of the specimens using confocal laser scanning microscope (CLSM). Data were analysed using anova and Tukey's post hoc test (P < 0.05). Although the FI groups showed higher DeltaVHN than the CFA groups, there were no significant differences between these fluoride application methods (P > 0.05). When the lesion depth was measured using CLSM imaging, there was also no significant difference between the FI and CFA groups (P > 0.05). In conclusion, FI was not significantly superior to CFA in terms of the remineralization effect.

Subjective food intake ability in relation to maximal bite force among Korean adults.

This study examined the relationship between the subjective food intake of 30 food types and their objective bite force to identify the key food items within the 30 food types to achieve a greater depth of masticatory function in Korean adults. A sample of 308 (112 males and 196 females) adults over the age of 20 (average age, 48.6) was selected among patients who visited four dental hospitals in Seoul, Korea. The subjective masticatory ability was evaluated through an interview with food intake ability questionnaires consisting of 30 food types ranging from hard to soft using a five-step Likert scale. The objective maximal bite force was measured using pressure-sensitive films. The relationship between the food intake ability and bite force was analysed and stratified according to age, gender, number of post-canine teeth lost and several clinical oral health indicators. The key foods were selected using correlation and factor analysis. The subjective food intake ability between the 30 foods and key foods were tested by cluster and one-way anova analysis. The Pearson's correlation coefficient between food intake ability and bite force was 0.45 (P < 0.01). The five key food items selected were dried cuttlefish, raw carrot, dried peanut, cubed white radish kimchi and caramel. The correlation coefficient between the food intake ability and bite force of these items was 0.51 (P < 0.01). These results suggest that the subjective food intake ability using the 30 and five key foods can be used to evaluate the masticatory function in Korean adults.

Effect of dentinal tubule occlusion by dentifrice containing nano-carbonate apatite.

This study evaluated the effects of the short-term use of a dentifrice containing nano-sized carbonate apatite (n-CAP) on the occlusion of the dentinal tubules using a scanning electron microscope (SEM) and an image analyser in vitro. One hundred human dentine specimens were wet ground with a silicone carbide papers and etched with 6% citric acid for 1 min to allow complete opening of the dentinal tubule. Specimens showing complete opening tubules were used as the baseline. The specimens were divided randomly into five groups: G1: 0% n-CAP, G2: 5% n-CAP, G3: 10% n-CAP, G4: 20% n-CAP and G5: 10%strontium chloride (SrCl(2)). Five specimens from each group were brushed by applying 50, 100, 250 and 500 strokes, respectively. All the specimens were evaluated by a SEM (x3000), and the degree of occlusion of the dentinal tubules was quantified using an image analyser. The results were analysed by one-way anova and a Tukey's test using the spss 12.0 statistical package program. The dentifrice containing 20% n-CAP for 50 strokes, which indicated 2-day use, showed the highest tubular occlusion than the other groups (P < 0.05). Moreover, this group showed 79.5% and 77.4% less open tubular area than the baseline and 0% n-CAP group, respectively. The groups containing various concentrations of n-CAP showed significant differences in the SrCl(2) group after tooth-brushing for 500 strokes, which indicated 17-day use. According to this examination of the short-term use of desensitizing dentifrices in vitro, the dentifrice containing 20% n-CAP was the most effective in occluding the dentinal tubules.

Dental caries and salivary immunoglobulin A in Down syndrome children.

OBJECTIVES: This study investigated the relationship between dental caries and the salivary Streptococcus mutans specific antibodies in Down syndrome children. METHODS: Nineteen children with Down syndrome and 41 normal children aged 8-17 years were selected. The oral health status (dental caries experience, pit and fissure depth, dental arch space, and Simplified Oral Hygiene Index) was examined and unstimulated saliva was collected. The total salivary immunoglobulin A (IgA) and S. mutans specific salivary IgA concentrations were measured using ELISA. RESULTS: The decayed and filled surface index of the deciduous teeth, and the decayed, missing, and filled surfaces index of the permanent teeth in Down syndrome children were significantly lower compared to those in normal children. The salivary S. mutans (serotype g and c) specific IgA concentrations were significantly higher in Down syndrome children than in the normal children. There was no significant difference in the tooth characteristics and oral hygiene between the two groups. CONCLUSIONS: The low caries prevalence in Down syndrome children appears to be due to immune protection caused by the elevated salivary S. mutans specific IgA concentrations.

A two-year longitudinal study of dental caries in permanent first molars of Korean elementary schoolchildren.

OBJECTIVE: This longitudinal study investigated dental caries increment in permanent first molars of Korean elementary schoolchildren. METHODS: A convenience sample of 722 children aged 7-9 years attending one urban elementary school was examined at baseline, with follow-up examinations at one and two years. Coronal surfaces of permanent first molars were scored with regard to caries experience and sealant status. RESULTS: Among sound occlusal surfaces at baseline, 21 percent of upper and 25 percent of lower surfaces developed caries during the two-year interval. In teeth that erupted between baseline and the first follow-up exam, over 10 percent of occlusal surfaces developed caries. Pit and fissure caries accounted for 93 percent of all new carious surfaces, while sealants had been placed on 16 percent of occlusal surfaces during the study. CONCLUSIONS: Recognizing the limitations of this convenience sample, dental sealants should be used more widely in this Korean population, and should be applied soon after tooth eruption.

Torsion of the pregnant uterus.

A 31-year-old woman, with a history of previous cesarean section and right oophorectomy, was admitted for a repeat cesarean section. After the commencement of surgery uterine torsion was diagnosed because of the anterior position of the remaining left ovary and tube, the absence of normal uterovesical peritoneum, and extremely engorged vessels in the lower uterine surface. Posterior classical hysterotomy was performed and a healthy female baby was delivered. Following delivery of the baby and suturing the incision site of the uterus, the contracted uterus was detorted and put back in the pelvic cavity. Extreme uterine torsion of 180 degrees at term is a rare obstetric event. This paper presents a case of uterine torsion at full term pregnancy in which the delivery and repositioning of the uterus was successful.

The outcome of the nonoperated contralateral hand in carpal tunnel syndrome.

It is not well known how the nonoperated contralateral hand behaves in bilateral carpal tunnel syndrome (CTS). The postoperative clinical course of the nonoperated contralateral hand in unilateral CTS is not well documented either. Of 324 CTS patients, the authors studied 37 who had carpal tunnel release on one hand only to evaluate the postoperative outcome of the nonoperated contralateral hand. The other 287 patients had operations on both hands. Seven patients were excluded because of missing data or because they could not be contacted. All 324 patients were subject to clinical and electrodiagnostic studies on both hands. The patients were divided into three groups. Group I was composed of patients who had bilateral CTS, diagnosed clinically and electrophysiologically, but who had surgery done only on the hand with the most pronounced symptoms. The patients in group II showed symptoms of CTS in one hand only. However, the opposite hand was diagnosed with subclinical CTS: Electrodiagnostic studies showed involvement of the median nerve, but without symptoms. Group III was composed of true unilateral CTS patients, diagnosed by symptoms and electrodiagnostic study. The results of the electrodiagnosis were categorized according to the severity of median nerve damage (mild, moderate, severe). The outcome and postoperative clinical course of the nonoperated contralateral hand were evaluated by electromyography and telephone survey. This method of survey was used because of the vast spread of patients throughout the country. Within 1 year, all 30 operated hands showed significant improvement, 20 of which belonged to group I. Regarding progress of the nonoperated contralateral hand, 10 patients showed improvement of one grade whereas 5 patients showed three grades of improvement. In another 5 patients there was no change whatsoever. In addition, from groups II and III there were 5 patients who showed no change in the nonoperated hand. The postoperative electromyographic findings of the nonoperated contralateral hand was not commensurate with the symptoms. However, regardless of electromyographic results, the nonoperated contralateral hand showed significant improvement (p < 0.0001). Patients with unilateral CTS did not experience any symptom development in the nonoperated contralateral hand.

Apicidin, a histone deacetylase inhibitor, inhibits proliferation of tumor cells via induction of p21WAF1/Cip1 and gelsolin.

Apicidin [cyclo(N-O-methyl-L-tryptophanyl-L-isoleucinyl-D-pipecolinyl -L-2-amino-8-oxodecanoyl)] is a fungal metabolite shown to exhibit antiparasitic activity by the inhibition of histone deacetylase (HDAC). In this study, we evaluated apicidin as a potential antiproliferative agent. Apicidin showed a broad spectrum of antiproliferative activity against various cancer cell lines, although with differential sensitivity. The antiproliferative activity of apicidin on HeLa cells was accompanied by morphological changes, cell cycle arrest at G1 phase, and accumulation of hyperacetylated histone H4 in vivo as well as inhibition of partially purified HDAC in vitro. In addition, apicidin induced selective changes in the expression of p21WAF1/Cip1 and gelsolin, which control the cell cycle and cell morphology, respectively. Consistent with increased induction of p21WAF1/Cip1, phosphorylation of Rb protein was markedly decreased, indicating the inhibition of cyclin-dependent kinases, which became bound to p21WAF1/Cip1. The effects of apicidin on cell morphology, expression of gelsolin, and HDAC1 activity in vivo and in vitro appeared to be irreversible, because withdrawal of apicidin did not reverse those effects, whereas the induction of p21WAF1/Cip1 by apicidin was reversible. Taken together, the results suggest that induction of histone hyperacetylation by apicidin is responsible for the antiproliferative activity through selective induction of genes that play important roles in the cell cycle and cell morphology.

Differential expression of four sweet potato peroxidase genes in response to abscisic acid and ethephon.

Expression of four peroxidase (POD) genes, three anionic PODs (swpa1, swpa2 and swpa3), and one neutral POD (swpn1) isolated from suspension cultures of sweet potato (Ipomoea batatas) were analyzed by measuring the accumulation of transcripts in suspension cultured cells and leaves of sweet potato in response to the stress-related plant hormones abscisic acid (ABA) and ethephon (an ethylene generating chemical). The four genes responded differently to ABA (0.1 mM) and ethephon (0.1 mM) in cultured cells and leaves. In suspension cultures, ABA reduced the expression levels of swpa1, swpa2, and swpn1, but did not affect the level of swpa3. Ethephon strongly increased expression levels of swpa3 and swpn1, and slightly increased the level of swpa1. The expression level of swpa2 was reduced. Expression levels in intact leaves, however, were significantly changed by this treatment. Expression of the swpa1 and swpa2 genes was induced 15 min after ABA treatment, followed by a decrease to a basal level after 3 h. A strong re-expression occurred after 12 h. Expression of the swpa3 and swpn1 genes occurred from 3 to 24 h after treatment. All four genes were differentially expressed 12 h after ethephon treatment. The swpa2 gene was strongly expressed immediately after ethephon treatment. The results indicate that each POD gene is differentially regulated by ABA and ethylene in whole plants and in cultured cells in vitro.

Hydrogen peroxide activates p70(S6k) signaling pathway.

We investigated a possible role of reactive oxygen species (ROS) in p70(S6k) activation, which plays an important role in the progression of cells from G(0)/G(1) to S phase of the cell cycle by translational up-regulation of a family of mRNA transcripts that encode for components of the protein synthetic machinery. Treatment of mouse epidermal cell JB6 with H(2)O(2) generated extracellularly by glucose/glucose oxidase led to the activation of p70(S6k) and p90(Rsk) and to phosphorylation of p42(MAPK)/p44(MAPK). The activation of p70(S6k) and p90(Rsk) was dose-dependent and transient, maximal activities being in extracts treated for 15 and 30 min, respectively. Further characterization of ROS-induced activation of p70(S6k) using specific inhibitors for p70(S6k) signaling pathway, rapamycin, and wortmannin revealed that ROS acted upstream of the rapamycin-sensitive component FRAP/RAFT and wortmannin-sensitive component phosphatidylinositol 3-kinase, because both inhibitors caused the inhibition of ROS-induced p70(S6k) activity. In addition, Ca(2+) chelation also inhibited ROS-induced activation of p70(S6k), indicating that Ca(2+) is a mediator of p70(S6k) activation by ROS. However, down-regulation of 12-O-tetradecanoylphorbol-13-acetate (TPA)-responsive protein kinase C (PKC) by chronic pretreatment with TPA or a specific PKC inhibitor Ro-31-8220 did not block the activation of p70(S6k) by ROS, indicating that the activation of TPA-responsive PKC was not required for stimulation of p70(S6k) activity by H(2)O(2) in JB6 cells. Exposure of JB6 cells to platelet-derived growth factor or epidermal growth factor led to a rapid increase in H(2)O(2), phosphorylation, and activation of p70(S6k), which were antagonized by the pretreatment of catalase. Taken together, the results suggest that ROS act as a messenger in growth factor-induced p70(S6k) signaling pathway.

A case of supernumerary teeth in the premaxilla, maxillary cuspid, and mandibular premolar regions.

A case of several developing supernumerary teeth is reported. A seven-year-old African-American boy presented with retained primary maxillary central incisors, two impacted mesiodens, and unerupted permanent maxillary central incisors. A dentigerous cyst was removed at the time of surgical removal of the mesiodens. Approximately fourteen months post-extraction, a new panoramic radiograph showed the presence of six previously unidentified developing and unerupted supernumerary teeth, one on each of the maxillary cuspid areas and two on the mandibular premolar regions bilaterally. Practitioners should be aware that supernumerary teeth may develop late. Thus, periodic reevaluation with appropriate radiographs is indicated, especially in patients who have presented with supernumerary teeth.

Relationship between nutritional intake and dental caries experience of junior high students.

This study was designed to investigate the relationship between nutritional intake and caries experience of junior high school students. The sample consisted of 295 boys and 356 girls in Kangwha county. Dependent variables were total caries experience, occlusal surface caries experience, smooth surface caries experience and DMFS score (Decayed, Missing, Filling Tooth Surface score). Independent variables such as pit and fissure retentiveness of first molars, oral hygiene status, intraoral acidogenicity were also measured by dentists. Other independent variables such as toothbrushing habits, socioeconomic conditions, between-meal eating habits, and daily nutritional intake were determined during an interview. Univariate and multivariate analysis was performed to evaluate how nutritional intake influences caries experience. The results were as follows: 1. The most influential factor on dental caries experience was pit and fissure retentiveness. 2. Dietary fiber and potassium were the significant nutritional factors on total caries experience and occlusal caries experience, and niacin was the significant nutritional factor on smooth surface caries. 3. DMFS score was positively associated with the daily amount of carbohydrate and niacin intake, and negatively associated with total energy intake. The above results suggested that pit and fissure retentiveness was the most influential factor on caries experience. However, in this study, the intake of potassium and niacin was identified to influence the caries experience in addition to confirming the well-known relationship between fiber and carbohydrate intake.