• Journal of Periodontal and Implant Science
• /
• v.39 no.1
• /
• pp.17-26
• /
• 2009

Purpose: The non-carious cervical lesion(NCCL) is a loss of tooth structure at the neck of affected teeth that is unrelated to tooth caries. The reported prevalence of NCCL varies from 5% to 85%. Prevalence and severity of lesions have been found to increase with age. They are becoming more significant as people live longer and become more aware of the importance of oral health. The purposes of this study were first, to examine the periodontal conditions associated with NCCL, and second, to investigate the clinical effects of class V restorations of NCCL on periodontal tissues. Materials and methods: The sample size was 982 teeth of 50 subjects(25 male, mean age $52{\pm}7$) who were seen at the Department of Periodontology, Pusan National University Hospital. At the baseline examination, clinical periodontal parameters were measured. After the initial examination, 24 patients who were absent from hypersensitivity were selected. The teeth with NCCL were randomly divided into the test and control groups. The teeth in the test group were restored with flowable resin; the control teeth were not restored. Six months later, the clinical examinations were repeated. The data were analyzed using the SPSS program. Results: The results were as follows: 1) NCCL occurred on 45.8% of examined teeth. The percentage of affected teeth was higher in maxillary and premolar teeth. 2) The shallow saucer type was the most common. 3) Teeth with NCCL had more gingival recession, lower attachment level, and higher incidences of bleeding on probing(BOP) and plaque than NCCL-free teeth. 4) Six months later, gingival recession, attachment level, the percentages of BOP and plaque in the test group were lower than in the control group(p<0.05). Conclusion: NCCLs were more found in maxillary teeth, especially in premolar teeth. The results suggest that the restoration of NCCL could affect some periodontal parameters favorably.

• Journal of Biosystems Engineering
• /
• v.7 no.2
• /
• pp.36-44
• /
• 1983

Farm population was rapidly decreasing due to shift of the people from farm sector to the non-farm sector caused by the economic growth of the country. Especially, a great shortage of farm labor in busy farming period in June and October is becoming a serious problem in maintaining or promoting land productivity. The peak of labor requirement in summer is caused by rice transplanting and barley harvesting. In order to reduce the restrictions imposed on farm management by the concurrence of labor requirement and the lack of labor, the experimental study for mechanization of barley harvesting has been carried out in the fields. 1. The machines for barley harvesting were knap-sack type reapers, windrow reaper (power tiller attachment), binder and combine. The order of higher efficiency of machine for barley harvesting was combine, binder, windrow reaper (WR), knapsack type reaper 1(KSTR1), and knap sack type reaper 2(KSTR2; mist and duster attachment). 2. The ratio of grain loss for the manual, binder, and combine plot was about four percent of total field yield. 3. The total yield of barley in 35 days and 40 days harvesting after heading were 514 kg and 507kg per 10 ares respectively. The yield of 35 days-plot was higher than other experimental plots. 4. The lowest yield was recorded in 30 days-plot due to the large quantity of immatured grains and having lighter 1000-grain weight. The ratio of immatured grains was 2.66 percent and 1000-grain weight was 29.4 grams. 5. The total harvesting cost of the windrow reaper was 10,178 won per 10 ares. It was the lowest value compared to other machines. The next were combine, binder, KSTR1, KSTR2, and manual in sequence. As a result, the optimum time of barley harvesting for mechanization was 35-40 days after heading. Combine, binder, and windrow reaper were recommended as the suitable machines for barley harvesting in the work efficiency. However, in total harvesting cost, the windrow reaper was the most promising machine for barley harvesting.

• Journal of Periodontal and Implant Science
• /
• v.44 no.4
• /
• pp.201-206
• /
• 2014

Purpose: Aggressive periodontitis, especially in its severe form, was traditionally considered to have an unfavourable prognosis. It required a complex treatment and its stabilization was often achieved by surgical therapy. The aim of this study was to investigate the results of nonsurgical periodontal treatment in severe generalized forms of aggressive periodontitis. Methods: Patients with advanced generalized aggressive periodontitis were included in the study. Probing depth (PD) of pockets ${\geq}7mm$ and clinical attachment level (CAL) of sites with attachment loss ${\geq}5mm$ were measured at baseline before nonsurgical periodontal treatment, at re-evaluation, and after treatment. The following other parameters were recorded: resolution of inflammation and bone fill. We compared the baseline values with re-evaluation and posttreatment values using the Friedman test. The Wilcoxon test with the Bonferroni correction was used for both re-evaluation and posttreatment values. Results: Seven patients with 266 periodontal sites were examined. A significant difference was found between values, reported as medians with interquartile ranges, for PD at baseline (7.94 [7.33-8.19] mm) and both re-evaluation (4.33 [3.63-5.08] mm) and posttreatment (3.54 [3.33-4.11] mm) values (P=0.002). A significant difference was also found between values for CAL at baseline (9.02 [7.5-9.2] mm) and both re-evaluation (6.55 [6.30-6.87] mm) and posttreatment (6.45 [5.70-6.61] mm) (P=0.002). Inflammation was resolved and angular bone defects were repaired in all cases. Conclusions: These therapeutic results suggest that this form of periodontitis could have positive outcomes after nonsurgical periodontal treatment. The reparative potential of tissue affected by severe aggressive periodontitis should encourage clinicians to save apparently hopeless teeth in cases of this form of periodontitis.

• Journal of Periodontal and Implant Science
• /
• v.35 no.4
• /
• pp.877-889
• /
• 2005

This study was designed to compare the effects of treatment using chitosan membrane $(Nanogide-C^{(R)})$ resorbable barrier with control treated by polylactic acid/polylacticglycolic acid membrane(PLA/PLGA membrane, $Biomesh^{(R)}$). 44 furcation defecs from 44 patients with class 2 furcation degree were used for this study, 22 sites of them were treated by chitosan membrane as experimental group and 22 site were treated by PLA/PLGA membrane as control group. Clinical parameters including probing depth, gingival recession, attachment level and radiographic examination were evlauated at base line, 1 month, 2 month and 3 month. after surgery. Statistical test used to analyze these data included paired t-test, one way ANOVA. The results are as follows : 1. Probing depth was significanlly decreased in the two group and there were significant differences between groups(p<0.05). 2. Gingival recession was not significanlly increased in the two group and there were no significant differences between groups(p<0.05). 3. Loss of attachment was statistically decreased in the two group and there were no significant differences between groups(p<0.05). 4. Horizontal bone level was significanlly increased in the two group and there were significant differences between groups(p<0.05). On the basis of these results, chitoans resorbable membrane has similar potential to PLA/PLGA membrane in GTR for furcation defect.

• Journal of Periodontal and Implant Science
• /
• v.25 no.3
• /
• pp.623-634
• /
• 1995

Periodontitis is characterized by gingival inflammation and results in periodontal pocket formation with loss of the supporting alveolar bone and connective tissue around the teeth. Therapeutic modalities should therefore aim not only at eliminating the gingival inflammatory process and preventing the progression of periodontal disease but also at reestablishing and regenerating the periodontal tissue previously lost to the disease. To achieve periodontal regeneration, progenitor cells must migrate to the denuded root surface, attach to it, proliferate and mature into an organized and functional fibrous attachment apparatus. Likewise, progenitor bone cells must also migrate, proliferate, and mature in conjunction with the regenerating periodontal ligament. Significant advances have been made during the last decade in understanding the factors controlling the migration, attachment and proliferation of cells. A group of naturally occuring molecules known as polypeptide growth factors in conjunction with certain matrix proteins are key regulators of these biological events. Of these, the fibroblast growth factor(FGF), platelet-derived growth factor(PDGF) , insulin like growth factor(CIGFs), transforming growth factor(TGFs), epidermal growth factor(EGF) and bone morphogenetic growth factor(BMPs) apper to have an important role in periodontal wound healing. The purpose of this study was to determine the effects of BMP on periodontal ligament cells. Human periodontal ligament cells were cultured from extracted tooth for non-periodontal reason. Cultured periodontal ligament cells were treated with BMP. Cellular activities were determined by MTT(3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide) assay and ALP(alkaline phosphatase) activity. The results were as follows ; Regardless of cultured time, cellular activities were stimulated by BMP. Also, BMP greatly increased alkaline phosphatase(ALP) in periodontal ligament cells. These results suggest that BMP not only have no cytotoxic effect on periodontal ligament cells, but also have osteogenic stimulatory effect on periodontal ligament cells.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.18 no.4
• /
• pp.363-368
• /
• 1985

Tagged and untagged sea urchins, Hemicentrotus pulcherrimus (A. Agassiz) were reared for 84 days in the laboratory, Vinyl tape and trapall paper were used as tag materials. The natural mortality, mortality by predation and shedding rate of tags of the tagged groups were examined, and the results were compared with those of untagged control group. The results of Chi-square test of natural mortality between tagged and control groups were very significative, however, the comparison between the two tagged groups was insignificative. No effect of tag attachment seems to be present at the point of natural predation by starfish, and $x^2-test$ between two the tagged groups on the loss rate of tags showed also insignificance. The mortality shortly after tagging seems to be negligible, and the distinct decreasing effect on growth due to tag attachment was not revealed because of insufficient individuals and rearing periods.

• Journal of Periodontal and Implant Science
• /
• v.44 no.6
• /
• pp.274-279
• /
• 2014

Purpose: To evaluate whether the levels of immunoglobulin G (IgG) antibody to Tanerella forsythia are associated with periodontal status. Methods: Patients with a diagnosis of chronic periodontitis were considered candidates for the study; thus 80 chronic periodontitis patients and 28 healthy persons (control group) were invited to participate in this investigation. The presence of T. forsythia was detected by polymerase chain reaction (PCR) analysis using primers designed to target the respective 16S rRNA gene sequences. Peripheral blood was collected from each subject to identify the IgG1 and IgG2 serum antibodies against T. forsythia. All microbiological and immunological laboratory processes were completed blindly, without awareness of the clinical status of the study patients or of the periodontal sites tested. Results: The bivariate analysis showed that lower mean levels of clinical attachment level (CAL) and probing depth were found in the presence of the IgG1 antibody titers against whole-cell T. forsythia; however, only the difference in CAL was statistically significant. In the presence of the IgG2 antibody titers against whole-cell T. forsythia, the periodontal parameters evaluated were higher but they did not show statistical differences, except for plaque. The unadjusted linear regression model showed that the IgG1 antibody against whole-cell T. forsythia in periodontitis patients was associated with a lower mean CAL (${\beta}=-0.654$; 95% confidence interval [CI], -1.27 to -0.28; P<0.05). This statistically significant association remained after adjusting for possible confounders (${\beta}=-0.655$; 95% CI, -1.28 to -0.29; P<0.05). On the other hand, smoking was a statistically significant risk factor in the model (${\beta}=0.704$; 95% CI, 0.24 to 1.38; P<0.05). Conclusions: Significantly lower mean levels of CAL were shown in the presence of the IgG1 antibody titers against whole-cell T. forsythia in periodontitis patients. Thus, the results of this study suggest that IgG1 antibody to T. forsythia may have been a protective factor from periodontitis in this sample.

• The Korean Journal of Community Living Science
• /
• v.27 no.3
• /
• pp.495-508
• /
• 2016

This study was conducted to recognize the need for diet and nutrition education to correct body-shape and eating habits that lead to eating disorders in college students. The relationship between diet and obesity was confirmed. Approximately 405 (male 46.4%, female 53.6%) students were evaluated by questionnaire in September 2014. The statistical program SAS (ver. 4.3) was used to evaluate the Chi-squared, F and T-value. The correlation between eating disorder risk and eating habits was evaluated by Pearson's correlation. Body type recognition was classified into nine steps up the body fatty (9) to skinny (1) to show their body. Eating disorder risk (KEAT-26) was composed of F1 (attachment factors for weight loss), F2 (attachment factors for binge eating, and food), and F3 (adjustment factor to eating their will. The risk of eating disorders in male 73.4% of low risk, in female 61.3% (p<0.05). According to body mass index, underweight groups recognized in the normal weight (53.7%), normal weight group was in overweight (29.1%) (p<0.001). According to body-type, the overweight group had a higher risk of eating disorders (68.2%). The KEAT-26 showed that the overweight and obese group were high-risk in F1 & F2, while the underweight group was high-risk in F3 (p<0.001). Recognized overweight showed the dangers of eating disorders, proper recognition of body-type and body mass index required. Tendency to seek a balanced diet was associated with eating disorders, no-imposed adequate diet for nutritional education would be made. Proper nutrition education for males is needed depending on the increased incidence of male eating disorders.

• Journal of Periodontal and Implant Science
• /
• v.53 no.4
• /
• pp.248-258
• /
• 2023

Purpose: This study aimed to characterize the early stages of periodontal disease and determine the optimal period for its evaluation in a mouse model. The association between the duration of ligation and its effect on the dentogingival area in mice was evaluated using micro-computed tomography (CT) and histological analysis. Methods: Ninety mice were allocated to an untreated control group or a ligation group in which periodontitis was induced by a 6-0 silk ligation around the left second maxillary molar. Mice were sacrificed at 1, 2, 3, 4, 5, 8, 11, and 14 days after ligature placement. Alveolar bone destruction was evaluated using micro-CT. Histological analysis was performed to assess the immune-inflammatory processes in the periodontal tissue. Results: No significant difference in alveolar bone loss was found compared to the control group until day 3 after ligature placement, and a gradual increase in alveolar bone loss was observed from 4 to 8 days following ligature placement. No significant between-group differences were observed after 8 days. The histological analysis demonstrated that the inflammatory response was evident from day 4. Conclusions: Our findings in a mouse model provide experimental evidence that ligature-induced periodontitis models offer a consistent progression of disease with marginal attachment down-growth, inflammatory infiltration, and alveolar bone loss.

• Journal of Periodontal and Implant Science
• /
• v.24 no.3
• /
• pp.529-540
• /
• 1994

Rapidly progressive periodontitis is known to be usually associated with systemic problems and improved with antibiotic therapy. Recent experiments in which bioresorbable polycaprolactone was polymerized with minocycline has shown that the system released effective antibiotic concentration during the 7 days' period. This clinical trial was to compare the efficacy of a minocycline film(poly-caprolactone+polyglycol+10% minocycline) insertion plus supragingival scaling(MS) or subgingival scaling & root planing(MSRP) with the scaling(S) or subgingival scaling & root planing alone(SRP), at improving the periodontal condition in RPP. Fifteen patients were examined for plaque accumulation, gingival inflammation, probing depth and attachment loss at baseline, then 1, 2, 4 and 8 weeks after 4 treatment regimens were randomly undergone in 4 comparable sites(PD>5mm, LA>3mm) in each subject. Results revealed statistically significant treatement effect with a reduction in a probing depth in SRP(2.0mm), MS(1.8mm), and MSRP(2.1mm). There was no significant reduction in the supragingival scaling alone group(0.6mm). Similarly, attachment levels were significantly improved in the SRP(1.5mm), MS(2.0mm) and MSRP(2.0mm) groups. Net % BOP reduction at 8 week compared to baseline was 6.7% (S), 26.7% (MS), 26.7% (SRP), and 33.3% (MSRP). MSRP produced the greatest improvement in BOP at 8 week. This data suggests that a subgingival minocycline delivery system as a adjunct to scaling alone or scaling & root planing may produce significant clinical benefits over scaling alone in rapidly progressive periodontitis patients.