• International Journal of Oral Biology
• /
• 제42권3호
• /
• pp.91-97
• /
• 2017

Although anti-aging activities of melatonin, a hormone secreted by the pineal gland, have been reported in senescence-accelerated mouse models and several types of cells, its impact and mechanism on the senescence of human dental pulp cells (HDPCs) remains unknown. In this study, we examined the impact of melatonin on cellular premature senescence of HDPCs. Here, we found that melatonin markedly inhibited senescent characteristics of HDPCs after exposure to hydrogen peroxide ($H_2O_2$), including the increase in senescence-associated ${\beta}$-galactosidase (SA-${\beta}$-gal)-positive HDPCs and the upregulation of p21 protein, an indicator for senescence. In addition, as melatonin attenuated $H_2O_2$-stimulated phosphorylation of c-Jun N-terminal kinase (JNK), while selective inhibition of JNK activity with SP600125 significantly attenuated $H_2O_2$-induced increase in SA-beta-gal activity. Results reveal that melatonin antagonizes premature senescence of HDPCs via JNK pathway. Thus, melatonin may have therapeutic potential to prevent stress-induced premature senescence, possibly correlated with development of dental pulp diseases, and to maintain oral health across the life span.

• Journal of Korean Academy of Oral Health
• /
• 제41권4호
• /
• pp.267-273
• /
• 2017

Objectives: Unmet needs for dental treatment are one of the potential contributing factors to poor oral health because oral health problems worsen if left untreated. This study aimed to demonstrate the prevalence of and the causes for unmet dental needs, and to evaluate the association between unmet needs for dental treatment and oral health status. Methods: Data on 3,883 subjects aged ${\geq}18years$ from the Korean National Oral Health Survey 2006 were analyzed. Information regarding unmet needs for dental treatment was obtained using standardized questionnaires. Eight trained dentists examined decayed, missing, or filled teeth (DMFT). Multiple regression models were built to assess the association between unmet needs for dental treatment and the DMFT scores. Results: The prevalence of perceived unmet needs for dental treatment was 34.7% among the adult Korean population. Economic constraints were the main cause (38.6%) for unmet dental needs. The average DMFT scores were higher in the subjects with unmet needs for dental treatment than in those without. In individuals with unmet needs for dental treatment within the past 1 year, the number of decayed teeth after adjusting for confounders was likely to be greater by 0.58 and that of missing teeth by 0.27 compared to that in their counterparts with no unmet dental needs in the past 1 year. Conclusions: Perceived unmet needs for dental treatment were significantly associated with poor oral health status among the adult Korean population. Further studies are needed to clarify the direct and indirect effects of unmet needs for dental treatment on an individual's oral health status by investigating critical variables of the causal pathways among perceived dental needs, dental care utilization, and oral health status.

• 대한치과교정학회지
• /
• 제37권5호
• /
• pp.331-340
• /
• 2007

이 연구는 한국인 여자 유명 모델과 일반인의 정면입술의 차이점을 비교하여 아름다운 입술의 특징을 규명하며 양악 전방 분절골절단술을 시행한 환자에서 정면입술의 변화를 측정하고 그 수술 결과를 한국인 모델과 비교하여 차이점을 알아보고자 하였다. 한국인 유명 모델 30명, 일반인 26명과 양악 전방 분절골절단술을 받은 환자의 10명을 대상으로 정면입술 부위의 12개의 선 길이, 홍순의 5개의 각도와 둘레 및 면적을 측정하였고, 통계분석은 unpaired & paired t-test를 이용하였다. 한국인 유명 모델 군과 일반인 군의 비교에서 하안면 얼굴 폭경, 하안면 수직 길이, 상홍순의 높이, 하순의 길이, 상홍순의 구각부 각도와 central bow의 각도는 의미 있는 차이로 일반인 군보다 유명 모델 군에서 작았다. 그러나, 입술의 폭, 하홍순의 높이, Cupid's bow tip간 거리와 하홍순의 구각부 각도는 유명 모델 군에서 컸고 입술의 둘레와 전체 면적에서도 일반인 군보다 쳐다 양악 전방 분절골절단술을 받은 환자의 정면입술에서는 하안면 얼굴 폭경, 상홍순의 높이, Cupid's bow tip에서 구각부까지의 길이와 상홍순의 면적이 통계적으로 의미 있는 변화를 보였고 한국인 유명 모델과의 비교에서 비슷한 수치를 나타내었지만 상순의 길이는 반대로 증가하였다. 연구의 결과는 교정치료 혹은 양악 전방 분절골절단술을 계획할 때 정면 입술 심미성을 평가하는데 도움이 될 것으로 생각된다.

• 치위생과학회지
• /
• 제22권4호
• /
• pp.222-232
• /
• 2022

Background: Self-leadership, an action strategy that can maximize individual capabilities, can affect the organizational commitment of dental hygienists and ultimately improve the quality of medical services. This study aims to demonstrate the need for self-leadership and organizational commitment for dental hygienists and develop measures to improve the quality of medical services. Methods: An online survey of dental hygienists working at dental hospitals and clinics in Seoul and Gyeonggi province, Republic of Korea was conducted from March 28 to May 1, 2022. A total of 341 questionnaires were returned and analyzed. The measurement tools were modified and supplemented based on the theories and models developed by Manz for self-leadership, Mowday for organizational commitment, and Cronin and Taylor for medical services. Descriptive statistics, independent t-tests, ANOVA, simple regression, and multiple regression analyses were performed using SPSS 25.0. Results: In leadership education, self-leadership is based on participation experience, the number of participants, and when and where it is received. Organizational commitment comes from participation experience, and the quality of medical services has been found to affect participation experience and location. Self-leadership had an effect on the quality of medical services (β=0.497, t=10.551, p<0.001; β=0.599, t=13.783, p<0.001; β=0.353, t=7.601, p<0.001) and organizational commitment was found to have a mediating effect. Conclusion: Dental hygienists' self-leadership has a positive effect on the quality of medical services through the formation of appropriate interrelationships within the organization. Therefore, self-leadership programs should be developed, participated in, and promoted to improve the self-leadership of dental hygienists. Moreover, hospitals should improve their environment to provide and improve self-leadership education.

• The Journal of Advanced Prosthodontics
• /
• 제7권3호
• /
• pp.199-206
• /
• 2015

PURPOSE. The present study investigated the influences of various gypsum materials on the precision of fit of CAD/CAM-fabricated prostheses and analyzed their correlation with surface roughness. MATERIALS AND METHODS. The master model of the mandibular right first molar was replicated, and four experimental groups based on two types of Type IV stone (GC Fujirock EP, Die keen) and two types of scannable stone (Aesthetic-Basegold, Everest Rock) were created to include a total of 40 specimens, 10 in each group. The surface roughness of the working models for the respective experimental groups was measured. Once the zirconia cores had been fabricated, the marginal and internal fits were measured with a digital microscope using the silicone replica technique. The mean and standard deviation of the respective points of measurement were computed and analyzed through the one-way ANOVA and Tukey's HSD test. The correlation between surface roughness and the precision of fit of the zirconia core was analyzed using the Pearson correlation analysis (${\alpha}$=.05). RESULTS. The zirconia cores fabricated from the scannable stone working models exhibited a superior precision of fit as compared to those fabricated from the Type IV stone working models. The correlation analysis results showed a clear positive correlation between surface roughness and the precision of fit of zirconia cores in all of the experimental groups (P<.05). CONCLUSION. The results confirmed that the surface roughness of dental working models has a decisive influence on the precision of fit of zirconia cores.

• 대한치과기공학회지
• /
• 제42권1호
• /
• pp.17-25
• /
• 2020

Purpose: The purpose of this study was to evaluate and compare the accuracy of definitive casts that are fabricated from digital intraoral impression and conventional impression technique. Methods: A master model(ANNA-4, Frasaco GmbH, Tettnang, Germany) with the prepared upper full arch tooth was used. Conventional impression and then stone model(n=10) were produced from this master model, and on the other hands, digital impressions were made with the CS-3600 intraoral scanner(n=10). Six linear measurements were recorded between landmarks, directly on each of the stone models on two occasions by a single examiner. Measurements were made with a digital caliper to the nearest 0.01mm from manual models and with the software(Delcam PowerSHAPE) from the virtual models. The t-student test for paired samples and intraclass correlation coefficient(ICC) were used for statistical analysis. Results: The measurement of two methods showed good reliability. The ICC of the two models were 0.88~0.91(stone model) and 0.94~0.99(digital model). The mean differences to master model for stone model and digital model were 0.10~0.14mm, and 0.14~0.20mm, respectively. Conclusion: The definitive casts obtained with digital intraoral technique model had significantly larger dimensions as compared to those of the stone model. However, the differences to the master model detected appear to provide enough accuracy and reliability for clinical application.

• Imaging Science in Dentistry
• /
• 제51권1호
• /
• pp.41-47
• /
• 2021

Purpose: This study aimed to compare the accuracy of 3-dimensional(3D) printed models derived from multidetector computed tomography (MDCT) and cone-beam computed tomography (CBCT) systems with different fields of view (FOVs). Materials and Methods: Five human dry mandibles were used to assess the accuracy of reconstructions of anatomical landmarks, bone defects, and intra-socket dimensions by 3D printers. The measurements were made on dry mandibles using a digital caliper (gold standard). The mandibles then underwent MDCT imaging. In addition, CBCT images were obtained using Cranex 3D and NewTom 3G scanners with 2 different FOVs. The images were transferred to two 3D printers, and the digital light processing (DLP) and fused deposition modeling (FDM) techniques were used to fabricate the 3D models, respectively. The same measurements were also made on the fabricated prototypes. The values measured on the 3D models were compared with the actual values, and the differences were analyzed using the paired t-test. Results: The landmarks measured on prototypes fabricated using the FDM and DLP techniques based on all 4 imaging systems showed differences from the gold standard. No significant differences were noted between the FDM and DLP techniques. Conclusion: The 3D printers were reliable systems for maxillofacial reconstruction. In this study, scanners with smaller voxels had the highest precision, and the DLP printer showed higher accuracy in reconstructing the maxillofacial landmarks. It seemed that 3D reconstructions of the anterior region were overestimated, while the reconstructions of intra-socket dimensions and implant holes were slightly underestimated.

• 대한치과교정학회지
• /
• 제16권2호
• /
• pp.81-97
• /
• 1986

The purpose of this study was to investigate the factors which cause the differences in the percentage of anterior overbite in spite of normal molar relationship in terms of skeletal, dental and dentoalveolar relations. The models and cephalograms taken from 154 subjects, 89 of shallow overbite and 65 of deep overbite ranging from 18 to 29 years of age were studied and analyzed statistically. The results were as follows. 1. In determining the percentage of anterior overbite, the significant differences were higher in the dental and dentoalveolar factors than in the skeletal factors and were higher in the proportional and angular measurements than in linear measurements. 2. The factor which had the greatest influence on the percentage of anterior overbite was the proportional parts of the dental and dentoalveolar heights. 3. The most influencing factor which determined the percentage of anterior overbite was the SN-MP angle among the skeletal factors.

• 한국치위생학회지
• /
• 제7권4호
• /
• pp.441-453
• /
• 2007

This study was conducted among 831 industrial workers in Gumi City in Gyung-Sang-Buk Do for the purpose of acquiring knowledge to improve quality of life though industrial workers' oral health promotion. Oral examination and questionnaire surveying were used to evaluate workers' oral health state and subjective health state and analyze their effect on quality of life. At the same time, the scales used in measuring the subjects' health state and quality of life-OHIP and WHOQOL-BREF-were validated for their constituent concepts and their relations were analyzed through structural modeling. The analysis results can be summarized as follows; The constituent concepts of OHIP and QOL factor structural models were validated since they were all in the range of appropriateness, as shown in the result of analysis using Indices of Fit-GFI, CFL, TLI and RMSEA. The result of analysis of constituent concepts to identitify the relations between OHIP and QOL confirmed that OHIP influences QOL.

• Journal of Korean Dental Science
• /
• 제5권2호
• /
• pp.48-53
• /
• 2012

Various ceramic implant systems made of yttria-stabilized tetragonal zirconia polycystal (Y-TZP) have become commercially available in recent years. A search of the literature was performed to assess the clinical success of dental Y-TZP implants and whether the osseointegration of Y-TZP is comparable to that of titanium, the standard implant material. No controlled clinical studies in humans regarding clinical outcomes or osseointegration could be identified. Clinical data were restricted to case studies and case series. Only 7 animal studies were found. Osseointegration was evaluated at 4 weeks to 24 months after placement in different animal models, sites and under different loading conditions. The mean bone-implant contact percentage was above 60% in almost all experimental groups. In studies that used titanium implants as a control, Y-TZP implants were comparable to or even better than titanium implants. Surface modifications may further improve initial bone healing and resistance to removal torque. Y-TZP implants may have the potential to become an alternative to titanium implants but cannot currently be recommended for routine clinical use, as no long-term clinical data are available.