• Imaging Science in Dentistry
• /
• v.42 no.1
• /
• pp.25-33
• /
• 2012

Purpose : This study was performed to determine the accuracy of linear measurements on three-dimensional (3D) images using multi-detector computed tomography (MDCT) and cone-beam computed tomography (CBCT). Materials and Methods : MDCT and CBCT were performed using 24 dry skulls. Twenty-one measurements were taken on the dry skulls using digital caliper. Both types of CT data were imported into OnDemand software and identification of landmarks on the 3D surface rendering images and calculation of linear measurements were performed. Reproducibility of the measurements was assessed using repeated measures ANOVA and ICC, and the measurements were statistically compared using a Student t-test. Results : All assessments under the direct measurement and image-based measurements on the 3D CT surface rendering images using MDCT and CBCT showed no statistically difference under the ICC examination. The measurements showed no differences between the direct measurements of dry skull and the image-based measurements on the 3D CT surface rendering images (P>.05). Conclusion : Three-dimensional reconstructed surface rendering images using MDCT and CBCT would be appropriate for 3D measurements.

• Imaging Science in Dentistry
• /
• v.40 no.1
• /
• pp.15-23
• /
• 2010

Purpose : This study was designed to compare the effective doses from low-dose and standard-dose multi-detector CT (MDCT) scanning protocols and evaluate the image quality and the spatial resolution of the low-dose MDCT protocols for clinical use. Materials and Methods : 6-channel MDCT scanner (Siemens Medical System, Forschheim, Germany), was used for this study. Protocol of the standard-dose MDCT for the orthodontic analysis was 130 kV, 35 mAs, 1.25 mm slice width, 0.8 pitch. Those of the low-dose MDCT for orthodontic analysis and orthodontic surgery were 110 kV, 30 mAs, 1.25 mm slice width, 0.85 pitch and 110 kV, 45 mAs, 2.5 mm slice width, 0.85 pitch. Thermoluminescent dosimeters (TLDs) were placed at 31 sites throughout the levels of adult female ART head and neck phantom. Effective doses were calculated according to ICRP 1990 and 2007 recommendations. A formalin-fixed cadaver and AAPM CT performance phantom were scanned for the evaluation of subjective image quality and spatial resolution. Results : Effective doses in ${\mu}Sv$ ($E_{2007}$) were 699.1, 429.4 and 603.1 for standard-dose CT of orthodontic treatment, low-dose CT of orthodontic analysis, and low-dose CT of orthodontic surgery, respectively. The image quality from the low-dose protocol were not worse than those from the standard-dose protocol. The spatial resolutions of both standard-dose and low-dose CT images were acceptable. Conclusion : From the above results, it can be concluded that the low-dose MDCT protocol is preferable in obtaining CT images for orthodontic analysis and orthodontic surgery.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• v.35 no.5
• /
• pp.329-334
• /
• 2009

Objective: To evaluate the ratio between bone-contact length and inter-segmental length of the rigid fixation screw used in bilateral sagittal split ramus osteotomy (BSSRO) for mandibular setback. Material and Methods: Records of 40 patients with Class III malocclusion were selected. 20 of them had BSSRO, while the other 20 had BSSRO with maxillary LeFort I osteotomy. All of the patients had three noncompressive bicortical screws inserted at the gonial angle through transcutaneous approach. Two screws were inserted antero-posteriorly above inferior alveolar nerve and one screw was inserted below. The lengths of bone-contact and that of inter-segmental part were measured using cone-beam computed tomography. Ratio between these two measured lengths was calculated. Results: Both bone-contact and inter-segmental lengths were longer in BSSRO group than in BSSRO with maxillary LeFort I osteotomy group. Ratio of bone-contact to inter-segmental length was lower in BSSRO group than in BSSRO with Lefort I group. Both bone-contact and inter-segmental lengths were longer at the antero-superior position than at the inferior position. However, their ratio showed little difference. Conclusion: This study suggest that stability of screws in BSSRO group was greater than in BSSRO with Lefort I group. Stability of screws at the antero-superior position was greater than at the inferior position. Ratio of bone-contact to inter-segmental lengths was 0.2 in average.

• Asian Pacific Journal of Cancer Prevention
• /
• v.17 no.8
• /
• pp.3663-3673
• /
• 2016

Cervical cancer (CaCx) is the second most fatal cancer contributing to 14% of cancers in Indian females, which account for 25.4% and 26.5% of the global burden of CaCx prevalence and mortality, respectively. Persistent infection with high-risk human papilloma virus (HPV- strains 16 and 18) is the most important risk factor for precursors of invasive CaCx. Comprehensive prevention strategies for CaCx should include screening and HPV vaccination. Three screening modalities for CaCx are cytology, visual inspection with acetic acid, and HPV testing. There is no Indian national policy on CaCx prevention, and screening of asymptomatic females against CaCx is practically non-existent. HPV vaccines can make a major breakthrough in the control of CaCx in India which has high disease load and no organized screening program. Despite the Indian Government's effort to introduce HPV vaccination in the National Immunization Program and bring down vaccine cost, challenges to implementing vaccination in India are strong such as: inadequate epidemiological evidence for disease prioritization, duration of vaccine use, parental attitudes, and vaccine acceptance. This paper reviews the current epidemiology of CaCx and HPV in India, and the current status of HPV vaccination in the country. This article stresses the need for more research in the Indian context, to evaluate interventions for CaCx and assess their applicability, success, scalability and sustainability within the constraints of the Indian health care system.

• Asian Pacific Journal of Cancer Prevention
• /
• v.17 no.8
• /
• pp.3687-3696
• /
• 2016

Cancer registration, an important component of cancer surveillance, is essential to a unified, scientific and public health approach to cancer prevention and control. India has one of the highest cancer incidence and mortality rates in the world. A good surveillance system in the form of cancer registries is important for planning and evaluating cancer-control activities. Cancer registration in India was initiated in 1964 and expanded since 1982, through initiation of the National Cancer Registry Program (NCRP) by the Indian Council of Medical Research. NCRP currently has twenty-six population based registries and seven hospital based registries. Yet, Indian cancer registries, mostly in urban areas, cover less than 15% of the population. Other potential concerns about some Indian registries include accuracy and detail of information on cancer diagnosis, and timeliness in updating the registry databases. It is also important that necessary data collection related quality assurance measures be undertaken rigorously by the registries to ensure reliable and valid information availability. This paper reviews the current status of cancer registration in India and discusses some of the important pitfalls and issues related to cancer registration. Cancer registration in India should be complemented with a nationwide effort to foster systematic investigations of cancer patterns and trends by states, regions and sub populations and allow a continuous cycle of measurement, communication and action.

• Korean Journal of Cleft Lip And Palate
• /
• v.6 no.2
• /
• pp.91-105
• /
• 2003

There are significant limitations in the precision of mandibular distraction in setting a desired occlusal and facial esthetic outcome. The purpose of this study is to present the simulation method for the distraction osteogenesis treatment planning. 3-D surgery simulation software programs V-works and V-Surgery(Cybermed, Seoul, Korea) were used from the 3D CT data in addition to the conventional data facial photography, panorama and cephalogram, dental cast model. We have utilized already for the various surgical procedures to get information preoperatively for the maxillofacial surgery like cancer localization and reconstructive surgery, orthognathic surgery and implant surgery in the department of Oral and Maxillofacial surgery, Seoul National University Hospital. On the software, bone cutting can be done at any place and any direction. Separated bone segment can be mobilized in all 3 dimensional direction. After the 3D simulation on the software program, mock surgery on the RP model can be performed. This planning method was applied to two hemifacial microsomia patients. With this protocol, we could simulate the movement of bony segment after maxillofacial distraction osteogenesis

• Korean Journal of Cleft Lip And Palate
• /
• v.6 no.1
• /
• pp.27-34
• /
• 2003

Patients with maxillary hypoplasia secondary to cleft lip and palate present numerous challenging problems for the oral and maxillofacial surgeon, These patients present with maxillary hypoplasia in multiclimensions, and often have thin or structually weak bone. This deformity has been traditionally corrected by Le Fort I osteotomy and acute skeletal advancement with wide surgical exposure. The long-term results of cleft patients with maxillary deficiency treated with this traditional approach has been sometimes disappointing, and an increased relapse tendency has been reported, Distraction osteogenesis for these cleft patients offers successful results while potentially minimizing the risk of relapse. Advancing the maxilla via distraction forces requires only a minor surgical procedure that maintains vascularity and neurosensory integrity. Moreover, the response of the facial soft tissues during maxillary distraction has proven to be more favorable than with a conventional LeFort I osteotomy. The purpose of this report is to present the use of maxillary distraction osteogenesis by rigid external distraction (RED) system for the treatment of patient with maxillary deficiency secondary to cleft lip and palate.

• Journal of dental hygiene science
• /
• v.20 no.3
• /
• pp.136-145
• /
• 2020

Background: Hepatitis B is an important public health problem as one of the leading causes of morbidity and mortality. The aim of this study was to compare the theoretical and practical knowledge levels of dental assistant students about Hepatitis B Virus. Methods: The 1st and 2nd grade students of the Oral and Dental Health program were invited to participate in the survey. Out of the 68 invited students, 61 completed the questionnaire. The average ages of the male and female students surveyed were 20.27±1.45 and 19.56±1.16, respectively. A total of 34 questions were asked, of which 15 measured basic theoretical knowledge and 19 assessed basic practical knowledge. Results: There was no statistically significant difference between the students' knowledge for each question according to their sex and grade. When the questionnaire was grouped into basic theoretical and basic practical knowledge levels, both were observed to be high. While the lowest correct answer rate was 35.00% for the questions about practical applications, it was 31.14% for the questions measuring the level of theoretical knowledge. There was no statistically significant difference when the levels of knowledge of 1st and 2nd grade students were compared. Students answered the majority of the questions correctly, and ranged between 71% and 100%. Conclusion: Students' high level of basic theoretical knowledge can be a result of their in-class education on the fundamentals. However, their knowledge about the correct approaches in practical applications indicates the beneficial role of having well-defined criteria and prevention protocols that are required in hospitals and the effectiveness of their environmental orientations.

• Journal of Periodontal and Implant Science
• /
• v.46 no.3
• /
• pp.197-206
• /
• 2016

Purpose: The aim of this study was to evaluate alterations of papilla dimensions after orthodontic closure of the diastema between maxillary central incisors. Methods: Sixty patients who had a visible diastema between maxillary central incisors that had been closed by orthodontic approximation were selected for this study. Various papilla dimensions were assessed on clinical photographs and study models before the orthodontic treatment and at the follow-up examination after closure of the diastema. Influences of the variables assessed before orthodontic treatment on the alterations of papilla height (PH) and papilla base thickness (PBT) were evaluated by univariate regression analysis. To analyze potential influences of the 3-dimensional papilla dimensions before orthodontic treatment on the alterations of PH and PBT, a multiple regression model was formulated including the 3-dimensional papilla dimensions as predictor variables. Results: On average, PH decreased by 0.80 mm and PBT increased after orthodontic closure of the diastema (P<0.01). Univariate regression analysis revealed that the PH (P=0.002) and PBT (P=0.047) before orthodontic treatment influenced the alteration of PH. With respect to the alteration of PBT, the diastema width (P=0.045) and PBT (P=0.000) were found to be influential factors. PBT before the orthodontic treatment significantly influenced the alteration of PBT in the multiple regression model. Conclusions: PH decreased but PBT increased after orthodontic closure of the diastema. The papilla dimensions before orthodontic treatment influenced the alterations of PH and PBT after closure of the diastema. The PBT increased more when the diastema width before the orthodontic treatment was larger.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.34 no.4
• /
• pp.718-724
• /
• 2007

A case of dentinal dysplasia type I is presented. Dentin dysplasia type I is a rare dental anomaly that is characterized by disturbance in dentin formation. It appears to be normal clinically, but, radiographically, it is characterized by obliteration of all pulp chambers and short, blunted, and malformed roots. Histological analysis shows whorls of tubular dentin and atypical osteodentin. In this case, features of dentin dysplasia type I in mixed dentition is presented. The clinical, radiographic, and histopathological findings of this condition are described along with its management.