Masticatory Performance and the Related Factors in Korean Children and Adolescents / 대한소아치과학회지

This study aimed to evaluate the masticatory performance of Korean children and adolescents and to investigate related factors. Early loss of primary molars, degree of occlusion of first molars, occlusal relationship of first molars, and presence of anterior crossbite were considered. From March 2020 to July 2021, 56 children and adolescents between the ages of 6 and 12 were included. The mixing ability index (MAI) was calculated to evaluate the masticatory efficiency of children and adolescents. The subjects were classified into three groups according to the number of early lost primary molars; normal dentition, 1 - 2 teeth lost, more than 3 teeth lost. The number of participants are 23, 18, and 15, respectively. There was no difference in the MAI values between the normal dentition group and the group has 1 - 2 teeth lost. However, when 3 or more primary molars were lost, the MAI value decreased and a significant difference was observed. This study is the first study to evaluate the masticatory performance of children and adolescents in Korea, and it will be helpful to pediatric dentists who evaluate the masticatory performance of children and adolescents and strive to improve the masticatory efficiency of children and adolescents in clinical practice.

Effect of nicotine on orthodontic tooth movement and bone remodeling in rats / 대한치과교정학회지

Objective@#To quantitatively analyze the effect of nicotine on orthodontic tooth movement (OTM) and bone remodeling in rats using micro-computed tomography and tartrate-resistant acid phosphatase immunostaining. @*Methods@#Thirty-nine adult male Sprague–Dawley rats were randomized into three groups: group A, 0.5 mL normal saline (n = 9, 3 per 3, 7, and 14 days); group B, 0.83 mg/kg nicotine (n = 15, 5 per 3, 7, and 14 days); and group C, 1.67 mg/kg nicotine (n = 15, 5 per 3, 7, and 14 days). Each animal received daily intraperitoneal injections of nicotine/saline from the day of insertion of identical 30-g orthodontic force delivery systems. A 5-mm nickel-titanium closed-coil spring was applied between the left maxillary first molar (M1) and the two splinted incisors. The rate of OTM and volumetric bone changes were measured using micro-computed tomography. Osteoclasts were counted on the mesial alveolar bone surface of the distobuccal root of M1. Six dependent outcome variables, including the intermolar distance, bone volume fraction, bone mineral density, trabecular thickness, trabecular volume, and osteoclast number, were summarized using simple descriptive statistics. Nonparametric Kruskal–Wallis tests were used to evaluate differences among groups at 3, 7, and 14 days of OTM. @*Results@#All six dependent outcome variables showed no statistically significant among group-differences at 3, 7, and 14 days. @*Conclusions@#The findings of this study suggest that nicotine does not affect OTM and bone remodeling, although fluctuations during the different stages of OTM in the nicotine groups should be elucidated in further prospective studies.

Effect of nicotine on orthodontic tooth movement and bone remodeling in rats / 대한치과교정학회지

Objective@#To quantitatively analyze the effect of nicotine on orthodontic tooth movement (OTM) and bone remodeling in rats using micro-computed tomography and tartrate-resistant acid phosphatase immunostaining. @*Methods@#Thirty-nine adult male Sprague–Dawley rats were randomized into three groups: group A, 0.5 mL normal saline (n = 9, 3 per 3, 7, and 14 days); group B, 0.83 mg/kg nicotine (n = 15, 5 per 3, 7, and 14 days); and group C, 1.67 mg/kg nicotine (n = 15, 5 per 3, 7, and 14 days). Each animal received daily intraperitoneal injections of nicotine/saline from the day of insertion of identical 30-g orthodontic force delivery systems. A 5-mm nickel-titanium closed-coil spring was applied between the left maxillary first molar (M1) and the two splinted incisors. The rate of OTM and volumetric bone changes were measured using micro-computed tomography. Osteoclasts were counted on the mesial alveolar bone surface of the distobuccal root of M1. Six dependent outcome variables, including the intermolar distance, bone volume fraction, bone mineral density, trabecular thickness, trabecular volume, and osteoclast number, were summarized using simple descriptive statistics. Nonparametric Kruskal–Wallis tests were used to evaluate differences among groups at 3, 7, and 14 days of OTM. @*Results@#All six dependent outcome variables showed no statistically significant among group-differences at 3, 7, and 14 days. @*Conclusions@#The findings of this study suggest that nicotine does not affect OTM and bone remodeling, although fluctuations during the different stages of OTM in the nicotine groups should be elucidated in further prospective studies.

Factors affecting objective and subjective masticatory ability assessment of Korean elderly people / 대한구강보건학회지

OBJECTIVES: The purpose of the study was to investigate factors affecting the assessment of objective and subjective masticatory ability in the elderly, and to evaluate masticatory ability assessment more accurately. METHODS: A total of 112 participants were recruited after oral examination in senior citizen welfare facilities. The participants' masticatory ability was evaluated objectively (Mixing ability index; MAI), and subjectively (Key food intake ability; KFIA). Participants' general characteristics and oral health-related variables were also recorded. Based on masticatory ability assessment, participants were classified as either high or low. IBM SPSS Statistics Ver.23.0 was used for all analyses, including descriptive statistics, Chi-square test, Mann-Whitney U test, Spearman rank correlation, and Logistic regression analysis. RESULTS: Higher masticatory ability was positively correlated with higher scores on MAI and KFIA. Additionally, there was a significant positive correlation between MAI and KFIA. When analyzing factors affecting objective and subjective masticatory ability assessments, Functional tooth units (FTUs) were revealed as a related factor. In subjective masticatory ability assessment, oral moisture, difficulty in chewing, and the Geriatric Oral Health Assessment Index (GOHAI) were also influential factors. CONCLUSIONS: In order to accurately assess masticatory ability, it is necessary to use both objective and subjective measures. Additionally, to improve the masticatory ability in the elderly, treatment should be provided to improve overall oral health and satisfaction.

Diagnostic accuracy of a combination of salivary hemoglobin levels, self-report questionnaires, and age in periodontitis screening

PURPOSE: This study evaluated the predictive performance of a combination of self-report questionnaires, salivary hemoglobin levels, and age as a non-invasive screening method for periodontitis. METHODS: The periodontitis status of 202 adults was examined using salivary hemoglobin levels, responses to 10 questions on a self-report questionnaire, and the Community Periodontal Index (CPI). The ability of those two variables and the combination thereof with age to predict the presence of CPI scores of 3-4 and 4 was assessed using logistic regression and receiver operating characteristic (ROC) curve analysis. RESULTS: CPI scores of 3-4 and 4 were present among 79.7% and 46.5% of the sample, respectively. The area under the ROC curves (AUROCs) of salivary hemoglobin levels for predicting prevalence of CPI scores of 3-4 and 4 were 0.63 and 0.67, respectively (with sensitivity values of 71% and 60% and specificity values of 56% and 72%, respectively). Two distinct sets of five questions were associated with CPI scores of 3-4 and 4, with AUROCs of 0.73 and 0.71, sensitivity values of 76% and 66%, and specificity values of 63% and 69%. The combined model incorporating both variables and age showed the best predictive performance, with AUROCs of 0.78 and 0.76, sensitivity values of 71% and 65%, and specificity values of 68% and 77% for CPI scores of 3-4 and 4, respectively. CONCLUSIONS: The combination of salivary hemoglobin levels and self-report questionnaires was shown to be a valuable screening method for detecting periodontitis.

Evaluation of fluoride bioavailability in toothpastes / 대한구강보건학회지

OBJECTIVES: The aims of this study were to determine the total fluoride concentration and bioavailable fluoride concentration in different toothpastes, based on a newly suggested method by the International Organization for Standardization (ISO), and to compare the measured concentrations with the concentrations written on the packaging. METHODS: The concentrations of total fluoride (TF) and bioavailable fluoride (BF) were measured in six toothpastes. For the TF measurement, 1 g of each toothpaste was mixed with dipotassium hydrogen phosphate (K2HPO4), and hydrogen chloride (HCl) was placed. After 24 hours, the samples were centrifuged and total ionic strength adjustment buffer (TISAB) solution was added. For the BF measurement, the toothpaste was mixed with K2HPO4 for only 1 minute. The samples were centrifuged, and then HCl was placed and allowed to stand for 24 hours. The TISAB solution was added subsequently. The concentration of fluoride ions was measured using a fluoride ion-selective electrode and calculated against a standard curve. RESULTS: The six toothpastes were composed of different fluoride compounds and abrasives. The measured TF concentration ranged from 624.99 ppm to 1,353.00 ppm, and the similarity to the declared fluoride concentration ranged from 53.48% to 93.31%. The measured BF concentration ranged from 587.61 ppm to 1,360.05 ppm, and the similarity to the expected fluoride concentration ranged from 41.97% to 93.80%. Two samples were clearly separated when the samples were centrifuged, whereas the remaining four samples had unclear supernatants. The clearly separated toothpastes (i.e., toothpastes 5 and 6) had BF concentrations that were similar to or lower than the declared fluoride concentrations and the measured TF concentrations. However, the unclearly separated toothpastes showed inconsistent relationships between the measured TF and BF concentrations. CONCLUSIONS: The measured TF and BF concentrations of the six toothpastes did not reach the expected fluoride concentration. This finding resulted from the different compositions and forms of the toothpastes. Therefore, the properties of toothpastes need to be considered when measuring their fluoride concentrations.

Efficacy of dentifrices containing policresulen in controlling dental plaque and gingivitis formation / 대한구강보건학회지

OBJECTIVES: This clinical study aimed to investigate if dentifrices containing policresulen would help to control dental plaque and gingivitis. METHODS: Seventy-eight eligible adults participated in this double-blind and randomized clinical study after an initial oral examination, calculus removal, and tooth prophylaxis. Two weeks after the procedure, the participants were assigned to three groups using the following dentifrices: (1) a dentifrice containing 0.22% NaF (control group); (2) a dentifrice containing 0.22% NaF and 100 ppm policresulen (policresulen group); and (3) a dentifrice containing 0.22% NaF, 100 ppm policresulen, and 1.00% bamboo salt (policresulen/bamboo group). The participants used only the provided dentifrice (for 1 min, twice a day, over 8 weeks) when brushing their teeth and followed their normal brushing habits. Dental plaque accumulation and gingivitis measurements were conducted using the Turesky modification of the Quigley-Hein plaque index (PI), the Loe and Silness gingival index (GI), and the percent bleeding on probing (%BOP) to obtain baseline data and 4- and 8-week data after grouping. RESULTS: A total of 73 participants aged 35.92+/-11.46 years (mean+/-SD) completed the study. The results after 8 weeks demonstrated statistically significant group-by-time interactions for PI, GI, and %BOP (P<0.001). The PI observed in the control groups increased over time up to 6%, while that observed in the dentifrice groups containing policresulen decreased by 5% (P<0.001). For GI and %BOP, the control group exhibited significantly higher values after 8 weeks, while the policresulen and the policresulen/bamboo groups revealed similar index values as the baseline after 4 and 8 weeks. The changes in all indices were significantly different between the control and the two experimental groups. There were no significant differences in the results obtained from the policresulen/bamboo group and the results obtained from the policresulen group. CONCLUSIONS: Use of dentifrices containing policresulen over 8 weeks demonstrated anti-plaque and anti-gingivitis efficacy compared to a control dentifrice.

Assessment of the erosive potential of carbonated waters / 대한구강보건학회지

OBJECTIVES: The aims of this study were to determine the erosive potential of several carbonated waters and to confirm the availability of a simple ISO protocol for screening the erosive potential of drinks. METHODS: A total of six carbonated waters were tested. Three products (Lemon-Sparkling water, Seagram, and Trevi) were domestic, and the other three (Perrier, San Pellegrino, and Rosbacher) were imported. Two kinds of carbonated drinks (Coca-Cola and Sprite) were used as controls. The erosive potential of each drink was assessed by measuring the initial pH (pH(I)), the final pH after degassing of carbon dioxide (pH(F)), and the titratable acidity to pH 5.5 (TA(5.5)) and 7.0 (TA(7.0)). The pH changes (DeltapH) caused by the addition of drinks to screening solutions were calculated according to the ISO protocol for evaluating the erosive potential of oral rinses. RESULTS: The overall erosive potential of the carbonated waters was lower than that of the control drinks. The pHI and pH(F) of the carbonated waters ranged from 3.94 to 5.84 and from 5.07 to 7.88, respectively. The Lemon-Sparkling water showed the highest erosive potential among the carbonated waters, having the lowest pH (3.94) and the highest TA(5.5) (1.67 ml). The DeltapH of all tested drinks ranged from -1.00 to 0.23. Also, the tendency of erosive potential measured by DeltapH was similar to that measured by TA(5.5). CONCLUSIONS: The carbonated waters tested in this study had a lower erosive potential than did the carbonated drinks. However, the erosive potential of domestic products was higher than that of imported products. The results of the ISO screening test could reflect the influence of the acid content as well as the pH of drinks. Therefore, this protocol could also be conveniently applied to evaluate the erosive potential of various drinks.

Short-term improvement of masticatory function after implant restoration

PURPOSE: Dental implants present several advantages over other tooth replacement options. However, there has been little research on masticatory function in relation to implant treatment. Therefore, the aim of the present study was to evaluate the improvement of masticatory function two weeks after implant restoration. METHODS: Masticatory ability was evaluated with the subjective food intake ability (FIA) and objective mixing ability index (MAI) methods. Fifty-four subjects with first and second missing molars completed the study. The subjects were asked to complete a self-reported questionnaire about 30 different food items, and to chew wax samples 10 times both before and two weeks after implant restoration. A total of 108 waxes were analyzed with an image analysis program. RESULTS: Dental implant restoration for lost molar teeth on one side increased the FIA score by 9.0% (P<0.0001). The MAI score also increased, by 14.3% after implant restoration (P<0.0001). Comparison between the good and poor mastication groups, which were subdivided based on the median MAI score before implant restoration, showed that the FIA score of the poor group was enhanced 1.1-fold while its MAI score was enhanced 2.0-fold two weeks after an implant surgery. CONCLUSIONS: Using the FIA and MAI assessment methods, this study showed that masticatory function was improved two weeks after implant restoration. In particular, the enhancement of masticatory function by implant restoration was greater in patients with relatively poor initial mastication than in those with good initial mastication.

A comparison of tooth brushing methods recommended in different countries / 대한구강보건학회지

OBJECTIVES: The aim of this study was to compare the tooth brushing methods recommended by dental associations and toothbrush manufacturers in various countries including South Korea. METHODS: Eighteen countries-6 Asian, 2 North American, 2 Oceanian, and 8 European-were selected from members of the OECD, EU, and APEC, using information obtained from the primary email address of each dental association and information obtained from the websites of the associations regarding the officially recommended tooth brushing methods. In addition, 12 major toothbrush manufacturers were selected based on their market share, including 4 Asian manufacturers, 2 North American, and 2 European. Information about recommended tooth brushing methods was obtained from their websites. RESULTS: The countries recommending a particular tooth brushing method by name were South Korea, Hong Kong, and Taiwan. While South Korea recommended the "rolling" technique, Hong Kong and Taiwan recommended the "bass" technique. Except for these countries, the other countries presented their recommended methods by explaining the initial position or motion of the toothbrush. The most commonly recommended method was tilting the brush head at an angle of 45 degrees to the gingival margin; this was recommended by 8 countries (44%) and 6 toothbrush manufacturers (75%). Brushing with a vibrating motion was also recommended by 9 countries (50%) and 4 manufacturers (50%). CONCLUSIONS: The most recommended brushing method was initially positioning the toothbrush at an angle of 45 degrees to the gingival margin and using a vibrating motion, which is effective against periodontal diseases. However, South Korea recommended the rolling technique, which is effective for controlling dental plaque. Given the high frequency with which periodontal disease occurs in South Korea, vibrating the toothbrush on the gingival margin should be recommended in addition to the rolling technique.

Assessing the clinical validity of a new caries activity test using dental plaque acidogenicity / 대한구강보건학회지

OBJECTIVES: This study was aimed at evaluating the clinical usability of a new caries activity test (Cariview(R)), which was based on the acidogenic potential of plaque by evaluating it's correlation with the DMFT index and comparing the results of Cariview(R) with those of previous caries activity tests in an adult group. METHODS: Teeth of 74 subjects were examined, and the DMFT index was calculated according to World Health Organization (WHO) criteria to determine the past caries experience. Caries activity tests were performed according to manufacturer's instructions. For Cariview(R) test, plaque samples were collected from the tooth surface by using a sterile cotton swab and incubated at 37degrees C for 48 h; an indicator was added to observe the color changes according to the plaque acidogenicity. The subjects were classified into three groups (Low, Moderate, High) according to the level of caries risk. The data were assessed using one-way ANOVA to compare the caries experiences of risk groups according to the caries activity test results, and the relationships between the caries activity tests and the DMFT index were evaluated. RESULTS: The overall mean DMFT index was 5.70+/-4.42. There was a significant difference in the DMFT index among the caries risk groups (Low, Moderate, High) according to the Cariview(R) test result (P=0.036). Further, there was a positive correlation between the Cariview(R) score and the DMFT index (r=0.23, P=0.047) and between the Cariview(R) score and the previous caries activity tests score (P<0.01). CONCLUSIONS: The new caries activity test (Cariview(R)) can be easily used at dental clinics and enables precise caries risk assessment.

In vitro quantification of occlusal caries lesion using QLF-D, ICDAS, and DIAGNOdent / 대한구강보건학회지

OBJECTIVES: To compare the QLF-D method and the ICDAS and DIAGNOdent techniques for in vitro quantification of occlusal caries and to assess the histological features of the caries. METHODS: One hundred and twenty-two extracted permanent teeth were selected, and the site of interest on the occlusal surface was examined using each detection method. The occlusal sites were classified according to the ICDAS II criteria based on the decision taken by two investigators, who have taken the ICDAS E-learning course. The examined site was then measured using the DIAGNOdent, and the peak value was recorded. In addition, by using the QLF-D, the occlusal site was photographed to obtain the DeltaFmax value. After all assessments were performed, the occlusal sites were vertically sectioned in order to assess the histological features. This was considered the gold standard. The histological criteria were graded using a 4-point scale as follows: S=sound (n=21), E1=limited enamel caries (n=27), E2=caries extending to the dento-enamel junction (n=49), D=caries involving the dentine (n=25). RESULTS: An ICDAS code between 0 and 4 was assigned to all the occlusal sites, and this revealed the QLF-D value, which was between -95 to 0. The DIAGNOdent value was between 8 and 99. The correlation values of QLF-D, ICDAS, and DIAGNOdent with the histological features were 0.68, 0.58, and 0.46, respectively (P<0.01). A highly significant correlation was observed between QLF-D and the gold standard, which showed a moderate correlation and an acceptable correlation was observed with ICDAS (r=0.75, P<0.01). A statistically significant difference was observed in the average QLF-D values of each histological grade i.e., -28.5 (S), -53.7 (E1), -68.1 (E2), and -84.4 (D). CONCLUSIONS: The QLF-D showed a significant correlation with the ICDAS and histological features. Therefore, visual inspection with QLF-D would improve the detection accuracy and ensure early diagnosis of dental caries.

Detection of early changes in caries lesion using QLF-D and OCT / 대한구강보건학회지

OBJECTIVES: We aimed to compare the differences in caries lesion changes when measured by QLF-D as fluorescence loss and by SS-OCT as lesion depth with respect to demineralized time, during formation of artificial early caries lesion. We also demonstrated that QLF-D and SS-OCT can be used effectively in monitoring the longitudinal progression of simulated caries lesions. METHODS: Ten bovine incisors were sectioned (5x4 mm) and embedded in epoxy resin. An acid-resistant nail varnish was applied to a part of the tooth surfaces to protect sound enamel (2x4 mm). To generate lesions, each specimen was immersed in 40 ml of a demineralizing gel for 20 days at 37degrees C. To measure mineral loss of the demineralized specimens, fluorescence loss (DeltaF, %) was measured by QLF-D and lesion depth (microm) was determined by SS-OCT from the captured cross-sectional image. All the specimens were analyzed daily by QLF-D image analysis software and SS-OCT image analysis program for 20 days. The repeated measures analysis of DeltaF and lesion depth was used. The paired t-test was used to assess differences between each day. The correlation between DeltaF and lesion depth was determined using the Pearson's correlation coefficient. RESULTS: On the 5th, 10th, and 15th day, compared to baseline values, DeltaF decreased in 12.7%, 25.0%, and 33.6% of the specimens, respectively, and the lesion depth increased in 9.9%, 16.0%, and 22.6% of the specimens, respectively. However, after 15 days, there was no change in the DeltaF and lesion depth. High significant correlation was identified between the resultant values of DeltaF obtained by QLF-D and those of lesion depth obtained by SS-OCT (r = -0.811, P<0.0001). CONCLUSIONS: The QLF-D and SS-OCT could detect subtle changes in mineral loss and lesion depth with respect to demineralized time. Furthermore, these devices were useful for monitoring changes in mineral amount and lesion depth.

Modification of surface pretreatment of white spot lesions to improve the safety and efficacy of resin infiltration / 대한치과교정학회지

OBJECTIVE: A low-viscosity resin (infiltrant) was used to inhibit the progression of white spot lesions (WSLs) and resolve associated esthetic issues. An alternative pretreatment was explored to increase the pore volume of the surface layer of the WSLs. Also, the penetration effects of the infiltrant were evaluated for various pretreatments. METHODS: Sixty two artificial lesions were fabricated on bovine teeth. As a positive control, 15% HCl gel was applied for 120 seconds. Further, 37% H3PO4 gel was applied for 30 seconds using three methods. The samples were divided as follows: H3PO4 only group, H3PO4 sponge group, and H3PO4 brush group. The acid was gently rubbed with the applicators (i.e., a sponge or brush) throughout the application time. To compare the effects of resin infiltration, twenty paired halves of specimens were treated with an infiltrant (ICON(R)). RESULTS: Thicknesses of the removed surface layers and infiltrated areas were evaluated by confocal laser scanning microscope. The positive control and the 37% H3PO4 brush group failed to show significant differences in the removed thickness (p > 0.05); however, the mean percentage of the infiltrated area was higher in the 37% H3PO4 brush group (84.13 +/- 7.58%) than the positive control (63.51 +/- 7.62%, p < 0.001). Scanning electron microscope observations indicate higher pore volumes for the 37% H3PO4 brush group than for the positive control. CONCLUSIONS: Application of 37% H3PO4 with a brush for 30 seconds increased the pore volume of WSL surface layers and the percentage of infiltrated areas in comparison to the use of 15% HCl for 120 seconds.

Analysis of the erosive effects of children's beverages using a pH-cycling model / 대한구강보건학회지

OBJECTIVES: The aims of this in vitro study were (1) to assess the erosive potential of several children's beverages in comparison to cola and orange juice, by using an in vitro pH-cycling model, and (2) to investigate the factors related to dental erosion caused by the beverages. METHODS: Eight different children's beverages (Chorongi, Capri-sun, Grateful nature wisdom, I-kicker, Koal-koal koala, My friend pororo, Qoo, and Strong zzanggu), Cola, and an orange juice, which are available in the Korean market, were used. To characterize each test beverage, the pH, titratable acidity to pH 7.0, concentration of calcium and phosphorus, and degree of saturation with respect to hydroxyapatite (DS(HAP)) were analyzed. Erosive potential of the test beverages was assessed by the depth of enamel loss observed in specimens subjected to pH cycling for 8 days. This cycle consisted of exposure to each beverage for 20 min, thrice daily, and to a remineralizing solution every day. The correlation between the depth of the enamel loss and the chemical properties of the beverages was assessed by Spearman's rank correlation coefficients and multiple linear regression tests (P<0.05). RESULTS: The depth of enamel loss caused by the beverages was found to vary from 0.11 to 105.47 microm. Enamel loss with all the children's beverages tested was lesser compared to that with Cola (P<0.05) but was similar or greater than that with orange juice, except in one beverage. The pH, concentration of calcium, and DS(HAP) were significantly correlated with the depth of enamel loss (rho=-0.842, rho=-0.796, and rho=-0.867, respectively; P<0.01). Multiple regression analysis showed that pH and concentration of calcium were impact variables for the erosive potential of test beverages (P<0.05). CONCLUSIONS: The children's beverages tested had lower erosive potential than Coca Cola, but five (I-kiker, Grateful nature wisdom, Qoo, Capri-sun, and Chorongi) of them had higher erosive potential than orange juice. Moreover, among the chemical properties of beverages, significant factors affecting enamel loss were pH value and concentration of calcium.

Comparison between the National Oral Health Survey Systems of the United States and South Korea / 대한구강보건학회지

In Korea, two kinds of National oral health surveys have been conducted to develop various oral health indices during the past decade. The system still needs to be improved further in terms of quality control for the examination system, data management, personnel empowerment, etc. Therefore, this study compares the National Oral Health Survey system of the United States (US) with that of South Korea. The US national surveys related to oral health were set from the 1970s, whereas Korea's national surveys have been initiated only recently; consequently, the US system is well organized and systematically managed by the professional personnel in governmental institutes, such as the Division of Oral Health in Centers for Disease Control. Furthermore, this study examines the scope of the examiner training program, and the methods for developing and implementing a standardized examination environment, data quality control, a data input system with automatic error checking, and data back up in the US. Considering the various factors involved in conducting nationwide epidemiological surveys as mentioned above, the structure and implementation methods of oral surveys in Korea clearly need to be improved.

Prevalence of demand for dentures in Korean elderly receiving governmental support funds / 대한구강보건학회지

OBJECTIVES: This study was conducted to investigate the status of elderly dentures wearers and to understand the relationship between elderly welfare recipients and general elderly Koreans. METHODS: A total of 3,810 subjects (3,458 general elderly and 352 elderly welfare recipients) over 65 years who participated in the Forth Korea National Health and Nutrition Examination Survey were examined. Oral examinations were conducted to ascertain those that were wearing dentures and those that needed dentures. A questionnaire measured chewing ability, concern about oral health, oral health behaviors, pronunciation ability and socio-demographic characteristics. The statistical analysis was done by using the SPSS 19.0 program. RESULTS: In the elderly welfare recipients, 28.2% was maxillary and 19.2% was mandible complete dentures and 36.0% had unmet denture treatment needs. In the general elderly, 21.7% was maxillary and 13.9% was mandible complete dentures and 24.3% had unmet denture treatment needs. The unmet denture treatment need in elderly welfare recipients was significantly higher than the general elderly after adjusting for other covariates. CONCLUSIONS: A denture service program is necessary for the elderly welfare recipients' oral health.

Comparison of bite force with dental prescale and unilateral bite force recorder in healthy subjects / 대한치과보철학회지

STATEMENT OF PROBLEM: The previous unilateral bite force recorder has several limitations for taking long time for measuring and causing discomfort to subjects. Because of these reasons, it could not use widely for epidemiological researches. However, "Dental Prescale System" which is new equipment for measuring bite force, is more convenient for measuring bite force than previous unilateral recorder. PURPOSE: The purpose of this study was to compare a new technique(Dental Prescale System) using pressure sensitive foils for recording of maximal jaw closing force with conventional measurement using unilateral bite force recorder. MATERIAL AND METHOD: This studies included 22 healthy dental students in college of dentistry, Yonsei university in Rep. of Korea. Mean age was 23.9 years. All subjects had continuous dental arches and no significant malocclusion or signs from the teeth and craniomandibular system. The Dental Prescale System (Fuji Film, Tokyo, Japan) consists of a horseshoe-shaped pressure sensitive sheet (50H, R type) and a computerized scanning system.(FPD705) We also used unilateral bite force recorder(Denbotics Co. Seoul, Rep.Korea) for comparing with Dental Prescale. RESULTS AND CONCLUSION: The total bite force recorded with Dental Prescale System (1423 N) was systematically higher than that recorded by unilateral bite force recorder.(256 N) However, the maximum bite force values measured in the two ways were significantly correlated (r=0.46, p<0.05). The Dental Prescale bite force calculated for first molar (208 N) was lower than that recorded by unilateral bite force recorder.(256 N) The two values were also very significantly correlated .(r=0.66. p<0.001) There were significantly different in bite force between two measurement methods. The reasons were first, unilateral bite force recorder measured only the bite force of a part of teeth, and Dental Prescale measured the total teeth force. Second, in measurement, a difference in muscle contraction appeared by an extent of mouth-opening. Third, unilateral bite force recorder has the reducing effect of the bite force by protective tape. Fourth, Dental Prescale has limitations during the computer scanning procedure. Therefore, Dental Prescale System is considered to be a very promising alternative to be conventional bite force recording methods.

Comparison of bite force with dental prescale and unilateral bite force recorder in healthy subjects / 대한치과보철학회지

STATEMENT OF PROBLEM: The previous unilateral bite force recorder has several limitations for taking long time for measuring and causing discomfort to subjects. Because of these reasons, it could not use widely for epidemiological researches. However, "Dental Prescale System" which is new equipment for measuring bite force, is more convenient for measuring bite force than previous unilateral recorder. PURPOSE: The purpose of this study was to compare a new technique(Dental Prescale System) using pressure sensitive foils for recording of maximal jaw closing force with conventional measurement using unilateral bite force recorder. MATERIAL AND METHOD: This studies included 22 healthy dental students in college of dentistry, Yonsei university in Rep. of Korea. Mean age was 23.9 years. All subjects had continuous dental arches and no significant malocclusion or signs from the teeth and craniomandibular system. The Dental Prescale System (Fuji Film, Tokyo, Japan) consists of a horseshoe-shaped pressure sensitive sheet (50H, R type) and a computerized scanning system.(FPD705) We also used unilateral bite force recorder(Denbotics Co. Seoul, Rep.Korea) for comparing with Dental Prescale. RESULTS AND CONCLUSION: The total bite force recorded with Dental Prescale System (1423 N) was systematically higher than that recorded by unilateral bite force recorder.(256 N) However, the maximum bite force values measured in the two ways were significantly correlated (r=0.46, p<0.05). The Dental Prescale bite force calculated for first molar (208 N) was lower than that recorded by unilateral bite force recorder.(256 N) The two values were also very significantly correlated .(r=0.66. p<0.001) There were significantly different in bite force between two measurement methods. The reasons were first, unilateral bite force recorder measured only the bite force of a part of teeth, and Dental Prescale measured the total teeth force. Second, in measurement, a difference in muscle contraction appeared by an extent of mouth-opening. Third, unilateral bite force recorder has the reducing effect of the bite force by protective tape. Fourth, Dental Prescale has limitations during the computer scanning procedure. Therefore, Dental Prescale System is considered to be a very promising alternative to be conventional bite force recording methods.

Risk factors for oral cancer: a case-control study

The purpose of this study was to investigate the relationship between oral cancer and such factors as smoking and drinking pattern, oral health status, dietary intake pattern, socio-economic status. Oral cancer patients and other disease patients who visited Yonsei University Dental Hospital from May to September in 2000 were selected as the study subjects. The numbers of cases and controls were 41, 108, respectively. Two groups were matched with age and sex for case control study. Oral examination and questionnaires survey was performed by the dentist. To assess the strength of associations between oral cancer and other variables, chi-square tests were performed. The results were as follows : 1. The durations of smoking and alcohol drinking were not related significantly with oral cancer. But the doses of smoking and alcohol intake increased the risk of oral cancer significantly(OR=2.52, 4.11, p<0.05). 2. Denture wearing, the number of missing teeth and spicy and salty food, coffee, tea and fresh fruit intake frequency did not significantly increase the risk of oral cancer. But low education level, residency in rural area increased risk of oral cancer significantly(p<0.01).