Perceptions and attitudes of dental hygienists toward radiation safety and protection in the Republic of Korea

To investigate the perceptions and attitudes of dental hygienists toward radiation safety management in Korea. A total of 800 dental hygienists were randomly selected for an anonymous survey, and 203 of them participated. The questionnaire items included the following: sex, career period, type of installed radiographic equipment, recognition of the diagnostic reference level (DRL), participation in radiation safety education, and attitudes toward radiation protection for both patients and dental hygienists. The participants were divided into two groups according to their years of experience (< 10 years versus ≥ 10 years). The difference between the groups was investigated according to frequency distribution. Fisher’s exact test or Pearson’s chi-square (χ2 ) test was used as appropriate. A regression analysis was performed to investigate the impact of wearing a thyroid collar for personnel protection during patient radiation exposure. The types of installed radiographic equipment included panoramic radiography (96.1%), cephalometric radiography (76.9%), intraoral radiography (72.9%), and cone-beam computed tomography (69.5%). Significant differences were observed in the learning pathway for the DRL (Fisher’s exact test, p < 0.05), satisfaction with radiation safety education (Pearson’s χ2 test = 5.3975, Pr = 0.02), and use of personnel radiation monitoring systems (Pearson’s χ 2 test = 18.1233, Pr = 0.000) between the groups. Significant differences were also observed in personnel protection using a thyroid collar and patient protection during panoramic radiography (odds ratio = 14.2). Dental hygienists with more than 10 years of experience were more satisfied with radiation safety education and more interested in radiation monitoring. Considering career experience, customized, continuous, and effective radiation safety management education should be provided.

Ameloblastoma with dystrophic calcification: A case report with 3-dimensional cone-beam computed tomographic images of calcification

This report presents a rare case of ameloblastoma with histopathologic and radiographic calcification, including 3-dimensional cone-beam computed tomographic (CBCT) images. A 22-year-old woman had hard swelling on the right mandible. Panoramic and CBCT images showed multilocular radiolucencies with internal calcification foci in the right mandible. Three-dimensional images clearly showed varying-sized radiopacities within the lesion from various angles. A histopathologic examination showed central squamous differentiation and more densely packed peripheral palisading ameloblastic cells. Many areas of keratin pearls and calcifications were also seen. Four previous reports have described 5 cases of ameloblastoma showing histopathologic calcification. This might be the first report to present the calcification of ameloblastoma on panoramic and CBCT images, especially on 3-dimensional images.

Low serum 25-hydroxyvitamin D levels, tooth loss, and the prevalence of severe periodontitis in Koreans aged 50 years and older

Purpose@#Vitamin D deficiency may cause bone loss and increased inflammation, which are well-known symptoms of periodontal disease. This study investigated whether serum 25-hydroxyvitamin D (25(OH)D) levels are associated with periodontal disease status and tooth loss. @*Methods@#Cross-sectional data from 5,405 individuals aged ≥50 years (2,253 males and 3,152 females) were obtained from the 2008–2010 Dong-gu study, a prospective cohort study of risk factors for chronic diseases. Periodontal examinations were conducted to evaluate the number of remaining teeth, the periodontal probing depth (PPD), the clinical attachment level (CAL), and bleeding on probing. The percentages of sites with PPD ≥4 mm and CAL ≥4 mm were recorded for each participant. The severity of periodontitis was classified using the Centers for Disease Control and Prevention and the American Academy of Periodontology case definitions.Serum 25(OH)D levels were classified as reflecting severe deficiency, deficiency, insufficiency, or sufficiency. Multivariate linear regression analysis was performed to assess the associations of serum 25(OH)D levels with periodontal parameters and the number of remaining teeth after adjusting for confounders including age, smoking status, alcohol consumption status, month of blood collection, and physical activity. Multivariate logistic regression was used to evaluate the association between serum vitamin D levels and severe periodontitis. An overall statistical analysis and a stratified analysis by sex were performed. @*Results@#Overall, the rates of severe deficiency, deficiency, insufficiency, and sufficiency were 6.5%, 67.9%, 22.4%, and 3.2%, respectively. After adjustment for confounders, vitamin D levels were directly associated with the number of remaining teeth, an association that was significant in males, but not in females. Sufficient serum 25(OH)D was associated with a low frequency of severe periodontitis. @*Conclusions@#This population-based cross-sectional study indicates that low serum 25(OH) D is significantly associated with tooth loss and severe periodontitis in Koreans aged 50 years and older.

Low serum 25-hydroxyvitamin D levels, tooth loss, and the prevalence of severe periodontitis in Koreans aged 50 years and older

Purpose@#Vitamin D deficiency may cause bone loss and increased inflammation, which are well-known symptoms of periodontal disease. This study investigated whether serum 25-hydroxyvitamin D (25(OH)D) levels are associated with periodontal disease status and tooth loss. @*Methods@#Cross-sectional data from 5,405 individuals aged ≥50 years (2,253 males and 3,152 females) were obtained from the 2008–2010 Dong-gu study, a prospective cohort study of risk factors for chronic diseases. Periodontal examinations were conducted to evaluate the number of remaining teeth, the periodontal probing depth (PPD), the clinical attachment level (CAL), and bleeding on probing. The percentages of sites with PPD ≥4 mm and CAL ≥4 mm were recorded for each participant. The severity of periodontitis was classified using the Centers for Disease Control and Prevention and the American Academy of Periodontology case definitions.Serum 25(OH)D levels were classified as reflecting severe deficiency, deficiency, insufficiency, or sufficiency. Multivariate linear regression analysis was performed to assess the associations of serum 25(OH)D levels with periodontal parameters and the number of remaining teeth after adjusting for confounders including age, smoking status, alcohol consumption status, month of blood collection, and physical activity. Multivariate logistic regression was used to evaluate the association between serum vitamin D levels and severe periodontitis. An overall statistical analysis and a stratified analysis by sex were performed. @*Results@#Overall, the rates of severe deficiency, deficiency, insufficiency, and sufficiency were 6.5%, 67.9%, 22.4%, and 3.2%, respectively. After adjustment for confounders, vitamin D levels were directly associated with the number of remaining teeth, an association that was significant in males, but not in females. Sufficient serum 25(OH)D was associated with a low frequency of severe periodontitis. @*Conclusions@#This population-based cross-sectional study indicates that low serum 25(OH) D is significantly associated with tooth loss and severe periodontitis in Koreans aged 50 years and older.

A comparative study of the deviation of the menton on posteroanterior cephalograms and three-dimensional computed tomography

PURPOSE: Facial asymmetry has been measured by the severity of deviation of the menton (Me) on posteroanterior (PA) cephalograms and three-dimensional (3D) computed tomography (CT). This study aimed to compare PA cephalograms and 3D CT regarding the severity of Me deviation and the direction of the Me. MATERIALS AND METHODS: PA cephalograms and 3D CT images of 35 patients who underwent orthognathic surgery (19 males and 16 females, with an average age of 22.1±3.3 years) were retrospectively reviewed in this study. By measuring the distance and direction of the Me from the midfacial reference line and the midsagittal plane in the cephalograms and 3D CT, respectively, the x-coordinates (x1 and x2) of the Me were obtained in each image. The difference between the x-coordinates was calculated and statistical analysis was performed to compare the severity of Me deviation and the direction of the Me in the two imaging modalities. RESULTS: A statistically significant difference in the severity of Me deviation was found between the two imaging modalities (Δx=2.45±2.03 mm, p<0.05) using the one-sample t-test. Statistically significant agreement was observed in the presence of deviation (k=0.64, p<0.05) and in the severity of Me deviation (k=0.27, p<0.05). A difference in the direction of the Me was detected in three patients (8.6%). The severity of the Me deviation was found to vary according to the imaging modality in 16 patients (45.7%). CONCLUSION: The measurement of Me deviation may be different between PA cephalograms and 3D CT in some patients.

The location of midfacial landmarks according to the method of establishing the midsagittal reference plane in three-dimensional computed tomography analysis of facial asymmetry

PURPOSE: The purpose of this study was to evaluate the influence of methods of establishing the midsagittal reference plane (MRP) on the locations of midfacial landmarks in the three-dimensional computed tomography (CT) analysis of facial asymmetry. MATERIALS AND METHODS: A total of 24 patients (12 male and 12 female; mean age, 22.5 years; age range, 18.2-29.7 years) with facial asymmetry were included in this study. The MRP was established using two different methods on each patient's CT image. The x-coordinates of four midfacial landmarks (the menton, nasion, upper incisor, and lower incisor) were obtained by measuring the distance and direction of the landmarks from the MRP, and the two methods were compared statistically. The direction of deviation and the severity of asymmetry found using each method were also compared. RESULTS: The x-coordinates of the four anatomic landmarks all showed a statistically significant difference between the two methods of establishing the MRP. For the nasion and lower incisor, six patients (25.0%) showed a change in the direction of deviation. The severity of asymmetry also changed in 16 patients (66.7%). CONCLUSION: The results of this study suggest that the locations of midfacial landmarks change significantly according to the method used to establish the MRP.

Interobserver agreement on the diagnosis of carotid artery calcifications on panoramic radiographs

PURPOSE: This study was performed to investigate the interobserver agreement on the detection of carotid artery calcifications on panoramic radiographs. MATERIALS AND METHODS: This study consisted of panoramic radiographs acquired from 634 male patients of the age of 50 years or older. Having excluded carotids of no diagnostic quality, 1008 carotids from the panoramic radiographs of the patients were interpreted by two oral and maxillofacial radiologists independently for the presence of carotid artery calcifications. Statistical analysis was used to calculate the interobserver agreement. RESULTS: Interobserver agreement was obtained for 932 carotids (92.4%). Inconsistent interpretation of 76 carotids (7.5%) between the two observers was found. Cohen's kappa value was 0.688 (p<0.001). CONCLUSION: The probability of a match between the two observers was substantially high.

The Factors Influencing on Employment Stress of University Students / 한국직업건강간호학회지

PURPOSE: This study examined to explore factors influencing on employment stress of university students. METHODS: The data were collected by structured questionnaires to students who agreed to be the subjects of this study. And 230 cases were finally analyzed. T-test, one-way ANOVA, Pearson's correlation coefficients, and multiple regression were conducted for data analysis using SPSS/WIN 18.0. RESULTS: Significant differences revealed in age, department of major, residental type and school year on employment stress by general characteristics. Also, employment stress showed negative correlation with self-esteem, and satisfaction in major. Self-esteem and satisfaction in major, department of major were confirmed as a factors influencing on employment stress and accounted for 36% of the variance. CONCLUSION: Further studies that discover factors influencing on employment stress of university students are needed, and also practical programs are necessary to decrease employment stress of university students.

Use of spherical coordinates to evaluate three-dimensional facial changes after orthognathic surgery

PURPOSE: This study aimed to assess the three-dimensional (3D) facial changes after orthognathic surgery by evaluating the spherical coordinates of facial lines using 3D computed tomography (CT). MATERIALS AND METHODS: A 19-year-old girl was diagnosed with class III malocclusion and facial asymmetry. Orthognathic surgery was performed after orthodontic treatment. Facial CT scans were taken before and after orthognathic surgery. The patient had a menton deviation of 12.72 mm before surgery and 0.83 mm after surgery. The spherical coordinates of four bilateral facial lines (ramal height, ramal lateral, ramal posterior and mandibular body) were estimated from CT scans before and after surgery on the deviated and opposite side. RESULTS: The spherical coordinates of all facial lines changed after orthognathic surgery. Moreover, the bilateral differences of all facial lines changed after surgery, and no bilateral differences were zero. CONCLUSION: The spherical coordinate system was useful to compare differences between the presurgical and postsurgical changes to facial lines.

Deviation of landmarks in accordance with methods of establishing reference planes in three-dimensional facial CT evaluation

PURPOSE: This study aimed to investigate the deviation of landmarks from horizontal or midsagittal reference planes according to the methods of establishing reference planes. MATERIALS AND METHODS: Computed tomography (CT) scans of 18 patients who received orthodontic and orthognathic surgical treatment were reviewed. Each CT scan was reconstructed by three methods for establishing three orthogonal reference planes (namely, the horizontal, midsagittal, and coronal reference planes). The horizontal (bilateral porions and bilateral orbitales) and midsagittal (crista galli, nasion, prechiasmatic point, opisthion, and anterior nasal spine) landmarks were identified on each CT scan. Vertical deviation of the horizontal landmarks and horizontal deviation of the midsagittal landmarks were measured. RESULTS: The porion and orbitale, which were not involved in establishing the horizontal reference plane, were found to deviate vertically from the horizontal reference plane in the three methods. The midsagittal landmarks, which were not used for the midsagittal reference plane, deviated horizontally from the midsagittal reference plane in the three methods. CONCLUSION: In a three-dimensional facial analysis, the vertical and horizontal deviations of the landmarks from the horizontal and midsagittal reference planes could vary depending on the methods of establishing reference planes.

Normal range of facial asymmetry in spherical coordinates: a CBCT study

PURPOSE: This study aimed to measure the bilateral differences of facial lines in spherical coordinates from faces within a normal range of asymmetry utilizing cone-beam computed tomography (CBCT). MATERIALS AND METHODS: CBCT scans from 22 females with normal symmetric-looking faces (mean age 24 years and 8 months) were selected for the study. The average menton deviation was 1.01+/-0.66 mm. The spherical coordinates, length, and midsagittal and coronal inclination angles of the ramal and mandibular lines were calculated from CBCT. The bilateral differences in the facial lines were determined. RESULTS: All of the study subjects had minimal bilateral differences of facial lines. The normal range of facial asymmetry of the ramal and mandibular lines was obtained in spherical coordinates. CONCLUSION: The normal range of facial asymmetry in the spherical coordinate system in this study should be useful as a reference for diagnosing facial asymmetry.

Three-dimensional finite element analysis of stress distribution for different implant thread slope and implant angulation / 대한치과보철학회지

PURPOSE: The purpose of this study was to find an inclination slope of the screw thread that is favorable in distributing the stresses to alveolar bone by using three dimensional finite element analysis. MATERIALS AND METHODS: Three types modelling changed implant thread with fixed pitch of 0.8 mm is the single thread implant with 3.8degrees inclination, double thread implant with 7.7degrees inclination and the triple thread implant with 11.5degrees inclination. And three types implant angulation is the 0degrees, 10degrees and 15degrees on alveolar bone. The 9 modelling fabricated for three dimensional finite element analysis that restored prosthesis crown. The crown center applied on 200 N vertical load and 15degrees tilting load. RESULTS: 1. The more tilting of implant angulation, the more Von-Mises stress and Max principal stress is increasing. 2. Von-Mises stress and Max principal stress is increasing when applied 15degrees tilting load than vertical load on the bone. 3. When the number of thread increased, the amount of Von-Mises stress, Max principal stress was reduced since the generated stress was effectively distributed. 4. Since the maximum principal stress affects on the alveolar bone can influence deeply on the longevity of the implants. When comparing the magnitude of the maximum principal stress, the triple thread implant had a least amount of stress. This shows that the triple thread implant gave a best result. CONCLUSION: A triple thread implant to increase in the thread slope inclination and number of thread is more effective on the distribution of stress than the single and double thread implants especially, implant angulation is more tilting than 10degrees on alveolar bone. Thus, effective combination of thread number and thread slope inclination can help prolonging the longevity of implant.

Comparison of the bone healing capacity of autogenous bone, demineralized freeze dried bone allograft, and collagen sponge in repairing rabbit cranial defects

OBJECTIVES: This study sought to evaluate the efficacy of collagen graft materials, as compared to other graft materials, for use in healing calvarial defects in rabbits. MATERIALS AND METHODS: Ten mm diameter calvarial defects were made in ten rabbits. The rabbits were then divided into 4 groups: control, autogenous bone graft, SureOss graft, and Teruplug graft. Bone regeneration was evaluated using histological and radiographic methods. RESULTS: Based on visual examination, no distinct healing profile was observed. At 4 weeks after treatment, histological analysis showed there was no bone regeneration in the control group; however, at 8 weeks after treatment, new bone formation was observed around the margin of the defective sites. In the autogenous bone graft group, new bone formation was observed at 4 weeks after treatment and mature bone was detected around the grafted bone after 8 weeks. In the SureOss graft group, at 4 weeks after treatment, acute inflammatory and multinuclear cells were noted around the grafted materials; at 8 weeks after treatment, a decrease in graft materials coupled with new bone formation were observed at the defective sites. In the Teruplug graft group, new bone formation was detected surrounding the bone margin and without signs of inflammation. There were statistically significant differences observed between the graft and control group in terms of bone density as evidenced by radiographic analysis using computed tomography (P<0.05), particularly for the autogenous bone graft group (P<0.001). CONCLUSION: These results suggested that autogenous bone, SureOss and Teruplug have the ability to induce bone regeneration as compared to an untreated control group. The osteogenic potential of Teruplug was observed to be lower than that of autogenous bone, but similar to that of SureOss.

The Factors Influence upon Job Maintenance of the Mentally Disabled with Job Experience / 한국직업건강간호학회지

PURPOSE: This study tried to explore factors influencing on job maintenance of the mentally disabled who employed before. The subjects of this study were the mentally disabled who participated in community mental health center and social rehabilitation center, there had experienced a job in the past. METHODS: The number of community centers were 27 places, there were located in different region. The number of participants were 221 persons agreed to this study. Data was analyzed by Mean, SD and logistic regression analyzation using SPSS/WIN 14.0. RESULTS: General character such as age was significant factor. Monthly pay and working a day in the midst of job related factors were significant. Moreover, job rehabilitation program satisfaction rate and social support revealed significant factors. CONCLUSION: On the basis of results, Job rehabilitation programs for job maintenance of the mentally disabled should be development and establish mediate strategies to improve social support to them.

Diagnostic reference levels in intraoral dental radiography in Korea

PURPOSE: The objectives of this study were to survey the radiographic exposure parameters, to measure the patient doses for intraoral dental radiography nationwide, and thus to establish the diagnostic reference levels (DRLs) in intraoral dental X-ray examination in Korea. MATERIALS AND METHODS: One hundred two intraoral dental radiographic machines from all regions of South Korea were selected for this study. Radiographic exposure parameters, size of hospital, type of image receptor system, installation duration of machine, and type of dental X-ray machine were documented. Patient entrance doses (PED) and dose-area products (DAP) were measured three times at the end of the exit cone of the X-ray unit with a DAP meter (DIAMENTOR M4-KDK, PTW, Freiburg, Germany) for adult mandibular molar intraoral dental radiography, and corrections were made for room temperature and pressure. Measured PED and DAP were averaged and compared according to the size of hospital, type of image receptor system, installation duration, and type of dental X-ray machine. RESULTS: The mean exposure parameters were 62.6 kVp, 7.9 mA, and 0.5 second for adult mandibular molar intraoral dental radiography. The mean patient dose was 2.11 mGy (PED) and 59.4 mGycm2 (DAP) and the third quartile one 3.07 mGy (PED) and 87.4 mGycm2 (DAP). Doses at university dental hospitals were lower than those at dental clinics (p<0.05). Doses of digital radiography (DR) type were lower than those of film-based type (p<0.05). CONCLUSION: We recommend 3.1 mGy (PED), 87.4 mGycm2 (DAP) as the DRLs in adult mandibular molar intraoral dental radiography in Korea.

Odontogenic Keratocyst Associated with an Ectopic Tooth in the Maxillary Sinus: A Report of Two Cases and a Review of the Literature

Odontogenic keratocysts are benign intraosseous tumors of odontogenic origin that occur most commonly in the jaw. In particular, they have a predilection for the angle and ascending ramus of the mandible. In contrast, odontogenic keratocysts arising in the maxillary sinus are relatively rare. Two such cases are reported herein. In addition, the English literature that concerns odontogenic keratocysts of the maxillary sinus is reviewed.

Application of spherical coordinate system to facial asymmetry analysis in mandibular prognathism patients

PURPOSE: The purpose of this study was to compare asymmetric mandibular prognathism individuals with symmetric mandibular prognathism individuals using a new alternate spherical coordinate system. MATERIALS AND METHODS: This study consisted of 47 computed tomographic images of patients with mandibular prognathism. The patients were classified into symmetric and asymmetric groups. Mandibular and ramal lines were analyzed using an alternate spherical coordinate system. The length as well as midsagittal and coronal inclination angle of the lines was obtained. The bilateral differences of the spherical coordinates of the facial lines were statistically analyzed in the groups. RESULTS: There were significant differences between the groups in bilateral difference of the length and midsagittal inclination angle of the lines (p<0.05). The bilateral difference of the length and midsagittal inclination angle of the lines has significant correlation with chin deviation (p<0.05). CONCLUSION: The new alternate spherical coordinate system was able to effectively evaluate facial lines. The bilateral difference of lengths and midsagittal inclination of the facial lines might contribute to the facial asymmetry in mandibular prognathism individuals.

Three dimensional evaluation of impacted mesiodens using dental cone beam CT / 대한구강악안면방사선학회지

PURPOSE: This study was performed to analyze the position, pattern of impacted mesiodens, and their relationship to the adjacent teeth using Dental cone-beam CT. MATERIALS AND METHODS: Sixty-two dental cone-beam CT images with 81 impacted mesiodenses were selected from about 2,298 cone-beam CT images at Chonnam National University Dental Hospital from June 2006 to March 2009. The position, pattern, shape of impacted mesiodenses and their complications were analyzed in cone-beam CT including 3D images. RESULTS: The sex ratio (M : F) was 2.9 : 1. Most of the mesiodenses (87.7%) were located at palatal side to the incisors. 79% of the mesiodenses were conical in shape. 60.5% of the mesiodenses were inverted, 21% normal erupting direction, and 18.5% transverse direction. The complications due to the presence of mesiodenses were none in 43.5%, diastema in 19.4%, tooth displacement in 17.7%, delayed eruption or impaction in 12.9%, tooth rotation in 4.8%, and dentigerous cyst in 1.7%. CONCLUSION: Dental cone-beam CT images with 3D provided 3-dimensional perception of mesiodens to the neighboring teeth. This results would be helpful for management of the impacted mesiodens.

Factors Influencing Job Stress in Work Experience of employees with Mentally Disabled / 정신간호학회지

PURPOSE: This study was done to identify the degree of job stress for workers with mentally disabled and factors influencing their job stress. METHODS: The participants in this study were employees with mental disabilities employed in job programs sponsored by community mental health centers and social rehabilitation centers. For this study, researchers conducted a survey with structured questionnaires with 221 employees. Data were analyzed using t-tests, ANOVA, Pearson's correlation coefficients and multiple regression analysis with SPSS/WIN 14.0. RESULTS: There were no significant differences in job stress according to general characters. However, there were significant differences in job stress according to type of employment and monthly-income. Multi-regression analysis showed that type of employment and social support affected job stress. CONCLUSION: The findings of this study indicate that following should be emphasized: conditions of employment such as type of employment and social support should be improved to decrease job stress and help the employee to remain in the job.

A Study on the Residential Relational Factors and Residential Service Needs of Persons with a Mental Disability / 정신간호학회지

PURPOSE: The purpose of this study was to explore residential needs of the mentally disabled which reflect residential relational factors and residential service needs. METHODS: The instrument used to measure residential needs of mentally disabled persons was the questionnaires reformed previous questionnaires. The instrument was tested with a sample of 307 participants who were registered in a day hospital, mental health center or social rehabilitation center. RESULTS: The needs for a residential facility for the mental disabled were significantly related with paying the entrance cost, monthly living cost and the decision making of the residents. The needs for residential services were independent living skills and an occupational rehabilitation program. CONCLUSION: The needs for residential services of the mentally disabled were varied because their diagnosis, symptom, functional level, treatment and personal priority are different. Therefore, we should develop various residential types and living services based on the needs and priorities of the mentally disabled.