• Journal of the Korean Academy of Child and Adolescent Psychiatry
• /
• v.27 no.1
• /
• pp.48-55
• /
• 2016

Objectives: Children with attention-deficit hyperactivity disorder (ADHD) may have deficits in time perception, as assessed by the time estimation task and the time reproduction task, however its age-related trajectory is not yet determined. Therefore we examined the correlation between accuracy of time perception tasks and age, and the association between accuracy of estimation tasks and reproduction tasks. Methods: Sixty-three patients with ADHD, aged 8 to 18 years tested the tasks for five time durations (2, 4, 12, 45, and 60 seconds). Accuracy of tasks was assumed differences (absolute values) between raw results of tasks and original time durations. Spearman's correlation analysis was performed to determine correlation between accuracy of time perception tasks and age. Multivariate regression was used to determine the association of accuracy of estimation tasks with accuracy of reproduction tasks. Results: Age showed correlation with accuracy of estimation tasks, but not with that of reproduction tasks. We observed that the higher the accuracy in 12, 45, and 60 seconds duration time reproduction, the higher the accuracy in longer seconds duration time estimation. Conclusion: Age was correlated with time estimation accuracy whereas there was no impact on time reproduction accuracy. Association of each of the two time perception tasks, particularly in longer time duration, suggested specific impairments in time perception.

• Journal of Oral Medicine and Pain
• /
• v.46 no.4
• /
• pp.125-130
• /
• 2021

Purpose: The dental age estimation of children is performed using dental maturity. Postmortem missing of the anterior teeth or the distortion of image of the anterior teeth in panoramic radiographs can make it difficult to analyze the development of the anterior teeth. This pilot study was conducted to derive a new age estimation method based only on the developmental stage of mandibular posterior teeth. Methods: This study was conducted using panoramic radiographs of 650 subjects aged 3 to 15 years old. The dental developmental stages of the lower left first premolar, second premolar, first molar and second molar were evaluated according to the Demirjian's criteria. The intra-/inter-observer reliability was evaluated, and multiple linear regression analyses were performed including the developmental stage of each tooth as an independent variable. Results: The intra-/inter-observer reliability was 0.9626 and 0.8877, respectively, and showed very high reproducibility. Multiple linear regression analyses were performed for males and females, and the age calculation table was derived by obtaining the intercept and the coefficient according to the development stage of each tooth. The coefficient of determination (r²) of the age calculation method was 0.9634 for male and 0.9570 for female subjects, and the mean difference between chronological age and estimated dental age was -0.42 and -0.21, respectively. Conclusions: This pilot study evaluated the developmental stages of four lower posterior teeth in the Korean group according to Demirjian's criteria, and derived age estimation method. The accuracy was lower than when more teeth were used, but it will be useful to estimate age of children when the anterior teeth are difficult to accurately analyze.

• Journal of Oral Medicine and Pain
• /
• v.10 no.1
• /
• pp.73-89
• /
• 1985

This study comprised 157 extracted teeth, 73 of the teeth originated from mates and 84 from females, the age range was 12-79 years. The correlation coefficient of each Gustafson's criteria in relation to age was carried out. Age estimation were performed on 157 teeth according to the method by Gustafson and by use of multiple regression, as used by Johanson, after evaluating the six criteria of Gustafson by multiple regression computer analysis. Two prediction formulas and standard deviations were compared with each other. The results were as follows : 1. The author found that six Gustafson's criteria had strong correlation with age except root resorption, and correlation coefficients were r = 0.79 (Transparent dentin), r=0.72 (Secondary dentin), r 0.69 (Periodontal change), r=0.63(Attrition), r = 0.39 (Root resorption), respecti vely. 2. The age estimation formula by Gustafson's method was calculated as follows: Y 8.88 + 3.52X r =0.87, r2 = 0.76, SD = 8.18, F = 483.56, P < 0.01 The age estimation formula by multiple regression was calculated as follows: Y 8.57 + 6.37T + 6.37T + 4.63P + 2.70S + 2.40C + 3.08A + 1.34R r= 0.89, r2 = 0.78, SD = 7.82, F = 91.62, P < 0.01, Durbin-Watson Coefficient = 1.09 3. In comparison of two estimation formulas, the formula by multiple regression, the method of Johanson, was found to be slightly more reliable than Gustafson's method. Gustafson's method SD = 8.18, Multiple regression (Johanson's method) SD = 7.82 4. It was reaffirmed that Gustafson's six criteria could be a independent variable in multiple regression analysis.

• Journal of Oral Medicine and Pain
• /
• v.39 no.4
• /
• pp.119-126
• /
• 2014

This review provides an overview of the most commonly used dental age estimation techniques which focus on radiological methods in Korean adults. The literature from 1995 through July 31, 2014, was searched, using PubMed, for publications in English language. In PubMed, the keywords 'tooth' OR 'dental' AND 'pulp' AND 'age estimation' were searched. Inclusion criteria was comprised of the following: the subjects were living adults and dental radiography (excluded computed tomography [CT] and cone-beam CT) was used to measure the pulpal size. Twenty articles that met the criteria were selected. The method of age estimation using dental radiographs for measuring pulp and tooth size was represented in all studies. The methods were assorted into three categories generally; Kvaal's, Ikeda's and Cameriere's methods. Those methods had certain limitations such as large error range and low correlation coefficient depending on populations, type of employed teeth and particular method. Various techniques and many studies have been published for age estimation from human teeth using dental radiographs, but those techniques showed various predictability and reliability. Therefore, future studies on larger samples with well-distributed age group using not only existing techniques but new techniques are necessary for deriving convincing results.

• Journal of the Korea Institute of Building Construction
• /
• v.6 no.3 s.21
• /
• pp.99-105
• /
• 2006

In this paper, the estimation of compressive strength of concrete incorporating fly ash subjected to high temperature is discussed. Ordinary Portland cement and fly ash cement(30% of fly ash) were used, respectively. Water to binder ration ranging from 30% to 60% and curing temperature ranging from $20^{\circ}C{\sim}65^{\circ}C$ were also adopted for the experimental parameters. According to results, at the high temperature, FAC had higher strength development at early age than OPC concrete and it kept its high strength development at later age due to accelerated pozzolanic reaction subjected to high temperature. For strength estimation, Logistic model based on maturity equation and Carino model based on equivalent age were applied to verify the availability of estimation model. It shows that fair agreements between calculated values and measured values were obtained evaluating compressive strength with logistic curve. The application of logistic model at high temperature had remarkable deviations in the same maturity. Whereas, the application of Carino model showed good agreements between calculated values and measured ones regardless of type of cement and W/B. However, some correction factors should be considered to enhance the accuracy of strength estimation of concrete.

• Journal of Environmental Science International
• /
• v.16 no.3
• /
• pp.347-355
• /
• 2007

In this paper, estimation of the compressive strength of the concrete incorporating blast furnace slag subjected to high temperature was discussed. Ordinary Portland cement and blast furnace slag cement (BSC;30% of blast furnace slag) were used, respectively. Water to binder ratio ranging from 30% to 60% and curing temperature ranging from $20^{\circ}C{\sim}65^{\circ}C$ were also chosen for the experimental parameters, respectively. At the high temperature, BSC had higher strength development at early age than OPC concrete and it kept its high strength development at later age due to accelerated latent hydration reaction subjected to high temperature. For the strength estimation, the Logistic model based on maturity equation and the Carino model based on equivalent age were applied to verify the availability of estimation model. It was found that fair agreements between calculated values and measured values were obtained evaluating compressive strength with logistic curve. The application of logistic model at high temperature had remarkable deviations in the same maturity. Whereas, the application of Carino model showed good agreements between calculated values and measured ones regardless of type of cement and W/B. However, some correction factors should be considered to enhance the accuracy of strength estimation of concrete.

• Smart Media Journal
• /
• v.10 no.2
• /
• pp.22-29
• /
• 2021

In the past decade, deep learning has been applied to various medical image analysis tasks. Skeletal bone age estimation is clinically important as it can help prevent age-related illness and pave the way for new anti-aging therapies. Recent research has applied deep learning techniques to the task of bone age assessment and achieved positive results. In this paper, we propose a bone age prediction method using a deep convolutional neural network. Specifically, we first train a classification model that automatically localizes the most discriminative region of an image and crops it from the original image. The regions of interest are then used as input for a regression model to estimate the age of the patient. The experiments are conducted on a whole-body scintigraphy dataset that was collected by Chonnam National University Hwasun Hospital. The experimental results illustrate the potential of our proposed method, which has a mean absolute error of 3.35 years. Our proposed framework can be used as a robust supporting tool for clinicians to prevent age-related diseases.

• Journal of Oral Medicine and Pain
• /
• v.33 no.3
• /
• pp.269-277
• /
• 2008

The purpose of this study was to estimate occlusal tooth wear and bruxism severity in TMD patients, and evaluate the effectiveness of the present age estimation method by occlusal tooth wear in TMD patients. Takei's age estimation method was applied to 163 subjects(56 controls, 107 TMD patients). The author analyzed the degree of occlusal tooth wear from the difference between estimated age and actual age. The obtained results were as follows: 1. In all age group, occlusal tooth wear in TMD patients is higher than those in asymptomatic controls. In 20's age group, a statistically significant difference was found. 2. In both gender, occlusal tooth wear in TMD patients is higher than those in asymptomatic control. In male, a significant difference was found. 3. Occlusal tooth wear in TMD patients with bruxism is significantly higher than that in control. 4. We found no significant difference in bruxism severity and occlusal tooth wear among the RDC/TMD subgroups. 5. Application of Takei's method would be still useful for age estimation in Korean. In case of age estimation of TMD patients using occlusal tooth wear, evaluation of the bruxism severity and appropriate correction according to age, sex and difference of geographical location should be considered.

• Journal of Oral Medicine and Pain
• /
• v.33 no.2
• /
• pp.167-176
• /
• 2008

We analyzed 121 age estimation clients who had visited oral medicine clinic, Chonbuk National University Hospital, from January 2000 to December 2007 to evaluate its characters in Jeonllabuk-do. The obtained results were as follows : 1. There was distinct difference in sex distribution(Male : 58.7%, Female : 41.3%) and more than half percent(55.4%) was over 50's. 2. The difference between registered and alleged age was the most in more than 5 years, and most of them were over 50's. 3. There were more clients who wanted to increase their age than to decrease and was no prominent difference in sex. Age estimation clients who wanted to decrease their age were predominant under 10 years old and in 20's, and those wanted to increase were predominant in 10's and over 30's. 4. The most reasons to correct age were related to welfare benefit. The purpose of age estimation was different according to each age groups; welfare benefit was the most over 50's, occupation in 40's and 50's, friendship in 30's and 40's, sibling-related in 50's, employment in 10's and 20's. 5. Age was estimated by the attrition of permanent tooth and pulp/tooth ratio from 20 years, root apex closure for 10's and calcification of permanent tooth under 10 years old. In cases that were difficult to estimate by use of the attrition of permanent tooth and pulp/tooth ratio, age was estimated by missing time of permanent tooth and the change of mandibular angle with age. 6. The estimated ages were close to alleged age in 77.7% of clients but the rest(22.3%) was close to registered age.

• Journal of Oral Medicine and Pain
• /
• v.25 no.2
• /
• pp.253-263
• /
• 2000

We collected age determination cases which were done at Yonsei university dental hospital, department of oral medicine from 1976 to 1999 to analyze it's tendency among Koreans. We analyzed 435 clients cases which were stored by age estimation program from January 1993 to December 1999. The results are as follows: 1. There were no significant difference in the sexual distribution (male : 52.0%, female : 48.0%) and more than half percent (51%) were 20's and 30's. 2. Among the age determination clients, those who wanted to decrease their age (50.3%) and those who wanted to increase their age (49.7%) shows similar in number. And the former case were predominant in the female clients, but the latter case in the male clients. Also the clients below six years of age were predominant in the former case, but the clients more than sixty were predominant in the latter case. 3. The purposes of age correction showed different distribution for ages: job or employment for 20's and 30's, marriage for 20's, registration for school for below six, welfare and other social services for 50 and older. 4. Age was estimated by Nolla's growth stage for 12 and under, calcification of the second and third molar for 12~20, and for 20 and over, Takei's tooth abrasion model was used. 5. The alleged age was in accordance with the documents and other information given by clients, but in the 20.6% of the estimation cases, the alleged age was discarded. In the results of the analysis of age determination cases in Koreans, many of the cases resulted from our historical turbulence and social distinctiveness, causing an increase in the necessity for age correction in each age group. For more accurate determination for each age group, further studies with Koreans must be done continuously.