Youngkyung Ko

Presence of Porphyromonas gingivalis and plasma cell dominance in gingival tissues with periodontitis

OBJECTIVE Porphyromonas gingivalis can invade and survive within its host epithelial cells. The aim of this study was to test our hypothesis that persistent presence of intracellular periodontal pathogens in gingival tissue causes the chronic inflammation and that an inappropriate immune response is a risk factor for periodontitis. METHODS Together with the presence of P. gingivalis, the distribution of B cells, plasma cells, and CD4(+), CD8(+), and FOXP3(+) regulatory T cells was evaluated in gingival tissues from healthy (n = 7) and periodontitis (n = 8) sites by in situ hybridization and immunohistochemistry, respectively. RESULTS Porphyromonas gingivalis was detected in proximity to inflammatory infiltrates in three and seven biopsies from the healthy and periodontitis sites, respectively. Compared with healthy sites, periodontal lesions contained a significantly increased number of each immune cell studied with a relative dominance of plasma cells over T cells. CONCLUSIONS Persistent bacterial invasion of gingival tissues in combination with a plasma cell-dominant immune response may be involved in the pathogenesis of periodontitis.

Association Between Alcohol Consumption and Periodontal Disease: The 2008 to 2010 Korea National Health and Nutrition Examination Survey

BACKGROUND A positive association has been reported between alcohol and periodontal disease. Therefore, this study is conducted to assess the relationship between alcohol intake and severity of periodontal disease in a large probability sample of the Korean population using the Korea National Health and Nutrition Examination Survey (KNHANES). METHODS Data from KNHANES, conducted between 2008 and 2010 by the Division of Chronic Disease Surveillance under the Korea Centers for Disease Control and Prevention and the Korean Ministry of Health and Welfare, were used for this study. The presence of periodontal treatment needs according to demographic variables and anthropometric and hematologic characteristics of the participants are presented as means with their standard errors. Multivariate logistic regression analyses were used to assess the associations of periodontal treatment needs with the amount of alcohol intake and other variables including smoking and the number of times of toothbrushing per day. RESULTS An association between drinking alcohol and periodontal treatment needs could be seen in men after adjustment for variables. Adjusted odds ratios (ORs) and their 95% confidence intervals (CIs) in males were 1.271 (1.030 to 1.568) for heavy drinkers after controlling for age, smoking, body mass index, exercise, education, income, white blood cell count, diabetes, hypertension, metabolic syndrome, and number of toothbrushing episodes per day (model 3). Adjusted ORs and their 95% CIs in males were 1.569 (1.284 to 1.916) for alcohol use disorders identification test (AUDIT) level ≥20 in model 3. ORs increased with the increase in alcohol consumption levels and AUDIT levels. Statistically significant correlations between drinking and periodontal treatment needs could not be seen in female heavy drinkers or female drinkers with AUDIT levels ≥20. CONCLUSIONS Men with higher alcohol intake were more likely to have a higher prevalence of treatment needs regardless of their age, socioeconomic factors, systemic conditions (including diabetes, hypertension, and metabolic syndrome), and number of times of toothbrushing per day in multivariable adjusted models. By contrast, in women, alcohol intake was not independently associated with periodontal treatment needs. Alcohol consumption was discovered to be a potential risk indicator for periodontal treatment needs in men in this study.

Evaluation of the effects of Angelicae dahuricae radix on the morphology and viability of mesenchymal stem cells

Angelicae dahuricae radix is a traditional herbal medicine used to treat various diseases in China and Korea, such as colds, headaches, rhinitis and psoriasis. Angelicae dahuricae radix has been used as an anti-inflammatory, analgesic, antipyretic and antioxidant remedy. This study was performed in order to evaluate the effects of the extracts of Angelicae dahuricae radix on the morphology and viability of mesenchymal stem cells derived from the gingiva. Mesenchymal stem cells derived from the gingiva were grown in the presence of Angelicae dahuricae radix at final concentrations that ranged from 0.001 to 100 µg/ml. The morphology of the cells was viewed under an inverted microscope, and the analysis of cell proliferation was performed with cell counting kit-8 (CCK-8) on days 1, 3 and 7. The cells in the control group had spindle-shaped, fibroblast-like morphology at days 1, 3 and 7 under optical microscopy. The shapes of the cells in 0.001, 0.01, 0.1, 1, 10 and 100 µg/ml Angelicae dahuricae radix were similar to the shapes of the cells in the control group. The relative values of the CCK-8 assays of 0.001, 0.01, 0.1, 1, 10, and 100 µg/ml Angelicae dahuricae radix were 102.5 ± 0.6, 133.3 ± 9.6, 148.4 ± 20.5, 147.7 ± 12.6, 132.3 ± 27.7 and 101.1 ± 4.6%, respectively, when the CCK-8 result of the control group on day 1 was considered to be 100%. There was a marginal increase in cell proliferation at 0.1 and 1 µg/ml groups at day 1; however, this did not achieve statistical significance (P=0.052). The relative values of the CCK-8 assays of 0.001, 0.01, 0.1, 1, 10 and 100 µg/ml Angelicae dahuricae radix were 96.5 ± 1.3, 89.3 ± 0.9, 90.3 ± 3.0, 84.8 ± 12.2, 92.3 ± 4.5 and 86.8 ± 11.7%, respectively, when the CCK-8 result of the control group on day 3 was considered to be 100% (P>0.05). The relative values of the CCK-8 assays of 0.001, 0.01, 0.1, 1, 10 and 100 µg/ml Angelicae dahuricae radix day 7 were 94.9 ± 22.3, 102.8 ± 22.1, 127.4 ± 7.4, 130.4 ± 1.3, 129.2 ± 10.8 and 124.8 ± 9.1%, respectively, when the CCK-8 result of the control group on day 7 was considered to be 100%, but there were no statistically significant differences among the groups (P>0.05). Within the limits of this study, Angelicae dahuricae radix at the tested concentrations did not produce statistically significant differences in the viability of stem cells derived from the gingiva.

Effects of titanium brush on machined and sand‐blasted/acid‐etched titanium disc using confocal microscopy and contact profilometry

OBJECTIVE Mechanical techniques, including scaling with metal, plastic, or ultrasonic instruments, rubber cup polishing, air-powder abrasive system and brushing with a conventional or a rotating brush, have been used for the debridement of dental implants. Recently, rotating brushes with titanium bristles (titanium brush) have been introduced for the debridement of implant surface when peri-implant osseous defects occur. The purpose of this study was to evaluate the effects of a titanium brush on machined (MA) and sand-blasted and acid-etched (SA) titanium surfaces using scanning electron microscopy, confocal microscopy and profilometry. Moreover, correlations between the two quantitative evaluation methods (confocal microscopy and contact profilometry) were assessed. MATERIALS AND METHODS Both MA and SA discs were treated with rotating titanium brush at 300 rpm under irrigation for a total of 40 s. Roughness measurements were taken with confocal microscopy and surface profilometry. Then, the MA and SA surfaces were evaluated using scanning electron microscopy to determine the changes of the surface properties. RESULTS Untreated MA surface demonstrated uniform roughness with circumferential machining marks, and scratch lines over the original surfaces were observed after treatment with the titanium brush. Similarly, the titanium brush produced noticeable changes on the SA titanium surfaces. However, this treatment with titanium brush did not significantly change the roughness parameters, including the arithmetic mean height of the surface (Sa) and the maximum height of the surface (Sz), in both MA and SA surfaces. Correlations between two evaluation methods showed a Pearson correlation coefficient of 0.98 with linear regression R(2) of 0.96. CONCLUSION This study showed that the treatment with the titanium brush did not significantly change the roughness parameters, including Sa and Sz, in both MA and SA surfaces. Correlations between confocal microscopy and surface profilometry showed high correlation with a Pearson correlation coefficient of 0.98.

In Vitro Analysis of the Efficacy of Ultrasonic Scalers and a Toothbrush for Removing Bacteria from Resorbable Blast Material Titanium Disks

BACKGROUND A resorbable blast material (RBM) surface is reported to have a higher bone-to-implant contact percentage than machined surfaces, but modified surfaces with rougher textures have been shown to favor colonization by bacteria and development of peri-implantitis. Therefore, this in vitro study compares the effects of different instruments on surface roughness and removal of bacteria from RBM titanium implant disks. METHODS RBM titanium disks were treated with various ultrasonic scaler tips and a toothbrush, and change in surface roughness was measured by confocal microscopy. The disks were incubated with bacteria, and instruments made of carbon or plastic, two metal ultrasonic scaler tips, or a toothbrush were used to remove the attached bacteria. The amount of remaining bacteria was evaluated using a crystal violet assay. RESULTS The change in surface structure following different treatment modalities was analyzed by confocal microscopy. A statistically significant decrease in the arithmetic mean value of RBM surfaces (R(a)) was observed after treatment with an ultrasonic scaler with a metal tip. The use of a metal tip (rather than a carbon or plastic tip) and brushing with dentifrice was more efficient in removing bacteria from the contaminated titanium surface according to the crystal violet assay. CONCLUSION Within the limits of this study, the use of a metal tip may be effective in removing bacteria from contaminated surfaces.

Effects of Asiasari radix on the morphology and viability of mesenchymal stem cells derived from the gingiva

Medicinal herbs used in traditional Oriental medicine, which have been in use clinically for thousands of years, are attractive sources of novel therapeutics or preventatives. Asiasari radix (A. radix) has been suggested for use in the treatment of dental diseases, including toothache and aphthous stomatitis. The aim of this study was to evaluate the effects of A. radix extracts on the morphology and viability of human stem cells derived from the gingiva. An Asiasarum heterotropoides extract was centrifuged and freeze-dried in a lyophilizer. Stem cells derived from the gingiva were grown in the presence of A. radix at concentrations ranging between 0.1 µg/ml and 1 mg/ml (0, 0.1, 1, 10, 100 and 1,000 µg/ml). Cell morphology was evaluated with an optical microscope and the viability of the cells was quantitatively analyzed with a cell counting kit-8 (CCK-8) assay for up to seven days. The untreated control group exhibited normal fibroblast morphology. The shapes of the cells following 0.1, 1, 10 and 100 µg/ml A. radix treatments were similar to those of the control group. However, a significant change was noted in the 1,000 µg/ml group on day 1, when compared with the untreated group. Furthermore, on day 7, the shapes of the cells following 100 and 1,000 µg/ml A. radix treatments were rounder and fewer cells were present, when compared with those of the control group. The cultures that grew in the presence of A. radix did not exhibit any changes in the CCK‑8 assay on day 2; however, significant reductions in cell viability were noticed following 100 and 1,000 µg/ml A. radix treatment on days 5 and 7. Within the limits of this study, A. radix influenced the viability of the stem cells derived from the gingiva. Thus, the direct application of A. radix to oral tissues may produce adverse effects at high doses. Therefore, the concentration and application time of A. radix requires meticulous control to obtain optimal results. These effects require consideration, if the use of A. radix is planned for the treatment of dental diseases.

Associations between the number of natural teeth in postmenopausal women and duration of lactation: The 2010–2012 Korea National Health and Nutrition Examination Survey

OBJECTIVES Lactation is reported to be associated with changes in maternal calcium homeostasis. The relationship between lactation and long-term oral health remains to be revealed. This study was aimed to evaluate the relationship between lactation and the number of natural teeth in postmenopausal women using nationally representative data. METHODS The data from the Korea National Health and Nutrition Examination Survey between 2010 and 2012 were used, and the analysis in this study was confined to 4211 respondents over 19 years old who had gone through menopause and had no missing values for the reproductive factors and outcome variables. The total number of natural teeth was then calculated after excluding third molars. Multiple logistic regression analyses were used to assess the associations of the number of natural teeth and lactation. RESULTS As the duration of total lactation increased, the number of natural teeth decreased. Average duration of lactation per child showed similar trends. The association between the total duration of lactation and the number of natural teeth showed an inverse relationship with a beta value of -0.0181 per day after adjustment, and the beta value of the average duration of lactation per child was -0.0287 after the adjustment. The odds ratios of the percentage of individuals with the number of teeth ≤ 27 tended to increase with increased duration of lactation. Adjusted odds ratios and 95% confidence intervals were 1.830 (1.009, 3.320); 1.142 (0.765, 1.704); 1.159 (0.807, 1.664); and 0.857 (0.563, 1.306) for lactation period of ≥ 25 months, 13-24 months, 7-12 months, ≤ 6 months, and no lactation, respectively. CONCLUSIONS This study investigated the relationship between the number of teeth and the total duration of lactation or an average duration of lactation per child using nationally representative data. Total duration of lactation and average duration of lactation per child were inversely related to the number of natural teeth. Lactation may be considered to be an independent risk indicator for tooth loss in Korean postmenopausal women.

The thickness of alveolar bone at the maxillary canine and premolar teeth in normal occlusion

Purpose The main purpose of this study was to investigate bone thickness on the buccal and palatal aspects of the maxillary canine and premolars using cone-beam computed tomography (CBCT). The differences between left- and right-side measurements and between males and females were also analyzed. Methods The sample consisted of 20 subjects (9 males and 11 females; mean age, 21.9±3.0) selected from the normal occlusion sample data in the Department of Orthodontics, The Catholic University of Korea. The thickness of the buccal and palatal bone walls, perpendicular to the long axis of the root were evaluated at 3 mm and 5 mm apical to cemento-enamel junction (CEJ) and at root apex. Results At the canines and first premolars regions, mean buccal bone thickness of at 3 mm and 5 mm apical to CEJ were less than 2 mm. In contrast, at the second premolar region, mean buccal bone thickness at 3 mm and 5 mm apical from CEJ were greater than 2 mm. Frequency of thick bone wall (≥2 mm) increased from the canine to the second premolar. Conclusions This result should be considered before tooth extraction and planning of rehabilitation in the canine and premolar area of maxilla. Careful preoperative analysis with CBCT may be beneficial to assess local risk factors and to achieve high predictability of success in implant therapy.

Effects of ultrasonic scaler tips and toothbrush on titanium disc surfaces evaluated with confocal microscopy.

Purpose Instrumentation to remove plaque from dental implants may cause damage to the implant surface, and previous studies that have evaluated the effects of the ultrasonic scalers and brushing in experimental settings reported that substantial changes were seen on implant surfaces after mechanical plaque removal. There is limited information on changes of the surface profile and roughness of sandblasted acid-etched (SLA) and machined titanium surfaces after treatment with different instruments in simulated clinical situations. The purpose of this study was to evaluate the effects of oral hygiene instruments including various types of ultrasonic tips in simulated clinical settings and brushing with dentifrice on machined and SLA titanium surface with confocal microscopy. Methods Both SLA and machined discs were treated with various ultrasonic scaler tips and brushing. Discs were either instrumented with 4 different ultrasonic scaler tips or brushed with dentifrice. The entire top surface of the discs was instrumented for a total of 40 seconds (20 seconds, 2 cycles). Brushing with dentifrice was done for 40 seconds. Roughness measurements were performed using a confocal microscope. Results The change of surface structure after different treatment modalities could be observed with the naked eye when compared with the untreated surface (SLA and machined groups). In case of SLA surfaces, the 2 metal tips produced greater changes on the titanium surfaces when compared with the plastic ultrasonic tips and brushing. On the machined discs, scratch lines over the original surfaces could be observed from all ultrasonic metal and plastic tips, but 2 metal tips produced significant and definite scratches on the original disc surfaces. Conclusions This study showed the effects of different types of ultrasonic tips and brushing with dentifrice on both SLA and machined titanium surfaces in simulated clinical setting. Within the limits of our study, we suggest that metal or plastic ultrasonic scaler tips may be applied as usual to treat the SLA surface of dental abutment or fixture surfaces without increasing the irregularities on the titanium surfaces. However, in case of machined surfaces, ultrasonic metal tips cannot be recommended because the surface becomes rougher after treatment. In addition, brushing of titanium, regardless of surface treatment (SLA and machined surfaces), resulted in reduction of surface roughness. Meticulous oral hygiene with brushing must be reinforced for the patients with dental implants to maintain the exposed implant surface clean. Brushing with dentifrice may facilitate maintaining the exposed fixture surface clean by smoothening the surface.

Associations Between the Periodontal Disease in Women Before Menopause and Menstrual Cycle Irregularity: The 2010-2012 Korea National Health and Nutrition Examination Survey.

AbstractThe association between menstrual cycle irregularities and system disease has been evaluated in previous studies. However, the association between periodontal disease and menstrual cycle irregularity has not been fully investigated. The study aimed to evaluate the relationship between periodontal disease and tooth loss in women before menopause and menstrual cycle irregularity using nationally representative data.This study performed a cross-sectional analysis and used hierarchical multivariable logistic regression analysis models. Data from Korean National Health and Nutrition Examination Survey (KNHANES) between 2010 and 2012 were analyzed. The analysis in this study was confined to a total of 1553 respondents over 19 years old who had not gone through menopause and had no missing values for the reproductive factors and outcome variables. A community periodontal index was greater than or equal to code 3 was used to define periodontal treatment needs.The risk of periodontal treatment needs tended to increase in the presence of menstrual cycle irregularity after adjustment for potential confounders (P for trend in the odds ratios = .0481 in model 1; 0.0613 in model 2; 0.0369 in model 3; 0.0456 in model 4). The number of natural teeth of 28 did not reach statistically significant differences (P for trend in the odds ratios = 0.2204 in model 1; 0.2373 in model 2; 0.2814 in model 3; 0.2609 in model 4).Menstrual cycle irregularity was positively associated with the risk of periodontal treatment needs in Korean women before menopause. However, there was no significant association between tooth loss and menstrual cycle irregularity. Menstrual cycle irregularity may be considered to be a potential risk indicator for periodontal treatment needs in Korean women before menopause.