• Imaging Science in Dentistry
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• 제51권4호
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• pp.429-438
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• 2021

Purpose: This study investigated the accuracy of laser-scanned models and 3-dimensional(3D) rendered cone-beam computed tomography (CBCT) compared to the gold standard (plaster casts) for linear measurements on dental arches. Materials and Methods: CBCT scans and plaster models from 30 patients were retrieved. Plaster models were scanned by an Emerald laser scanner (Planmeca, Helsinki, Finland). Sixteen different measurements, encompassing the mesiodistal width of teeth and both arches' length and width, were calculated using various landmarks. Linear measurements were made on laser-scanned models using Autodesk Meshmixer software v. 3.0 (Autodesk, Mill Valley, CA, USA), on 3D-rendered CBCT models using OnDemand 3D v. 1.0 (Cybermed, Seoul, Korea) and on plaster casts by a digital caliper. Descriptive statistics, the paired t-test, and intra- and inter-class correlation coefficients were used to analyze the data. Results: There were statistically significant differences between some measurements on plaster casts and laser-scanned or 3D-rendered CBCT models (P<0.05). Molar mesiodistal width and mandibular anterior arch width deviated significantly different from the gold standard in both methods. The largest mean differences of laser-scanned and 3D-rendered CBCT models compared to the gold standard were 0.12±0.23 mm and 0.42±0.53 mm, respectively. Most of the mean differences were not clinically significant. The intra- and inter-class correlation results were acceptable for all measurements(>0.830) and between observers(>0.801). Conclusion: The 3D-rendered CBCT images and laser-scanned models were useful and accurate alternatives to conventional plaster models. They could be used for clinical purposes in orthodontics and prostheses.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제47권6호
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• pp.432-437
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• 2021

Objectives: The mandible and other parts of the maxillofacial region suffer significant morbid injuries following road traffic accidents. Our study gives epidemiological description of mandibular fractures in Ghana and also evaluates the relevance of closed reduction and indirect fixation for managing mandibular fractures in low-resource health facilities in low-income countries like Ghana. Patients and Methods: This is a retrospective study involving 268 patients who reported to the Department of Oral and Maxillofacial Surgery of the Sunyani Regional Hospital with mandibular fractures from January 2010 to December 2019. Patient medical records were assessed for information on age, sex, fracture etiology, anatomic location of fracture, time of day of road traffic accident, and other associated injuries. Results: A total of 268 patients were included in this study (males, 216 [80.6%]; females, 52 [19.4%]). Motor vehicular accident (MVA) was the leading cause of mandibular fractures (202 injuries, 75.4%). Other etiologies included assault (39, 14.6%), gunshot (13, 4.9%), falls (12, 4.5%), and industrial accidents (2, 0.7%). Of the 161 male cases caused by MVA, 121 (75.2%) occurred at night and in the evening while the remaining 40 (24.8%) occurred in the morning and afternoon. Among all managed 222 patients, 212 (79.1%) were treated with closed reduction and indirect fixation technique while 10 (3.7%) were treated with open reduction and direct fixation. Conclusion: Closed reduction with indirect fixation could successfully be used to manage mandibular fractures in low resourced health facilities, especially in low-income countries. The poor lightening system on roads in Ghana is a major contributory factor to motor vehicular accidents.

• Journal of Korean Dental Science
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• 제15권1호
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• pp.61-67
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• 2022

Purpose: This study aimed to evaluate the accuracy of bite registration using intraoral scanner based on data trimming strategy for fremitus teeth. Materials and Methods: A reference model was designed by Medit Model Builder software (MEDIT Corp., Seoul). Tooth number 24 and 25 were separated as dies and tooth number 26 was prepared for full-coverage crown. Those were printed using a 3D printer (NextDent 5100). The scanning procedure was performed by a single trained operator with one intraoral scanner (i700; MEDIT Corp.). The scanning groups were divided as follows: group 1 (G1), no fremitus; group 2 (G2), 0.5 mm buccal fremitus in the maxillary left first and second premolar; and group 3 (G3), 1.5 mm buccal fremitus in the maxillary left first and second premolar. Each group was scanned 10 times and were analyzed using the reference model data. Surface-based occlusal clearance was analyzed at the prepared tooth to evaluate accuracy. Result: Mean values of control group (G1) were 1.587±0.021 mm. G2 showed similar values to those from the control group (1.580±0.024 mm before trimming strategy and 1.588±0.052 mm after trimming strategy). G3 showed significantly greater values (1.627±0.025 mm before trimming strategy and 1.590±0.024 mm after trimming strategy) and the differences were found between trimming strategy (P=0.004). Conclusion: Bite trimming strategy for fremitus teeth is a reliable technique to reduce inaccuracies caused by the mobility at maximum intercuspation.

• Imaging Science in Dentistry
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• 제52권3호
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• pp.303-308
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• 2022

Purpose: This technical report aims to describe and detail the use of micro-computed tomography for a reliable evaluation of the bulk-fill composite/tooth interface. Materials and Methods: Bulk-fill composite restorations in tooth cavities were scanned using micro-computed tomography to obtain qualitatively and quantitatively valuable information. Two-dimensional information was processed using specific algorithms, and ultimately a 3-dimensional (3D) specimen reconstruction was generated. The 3D rendering allowed the visualization of voids inside bulk-fill composite materials and provided quantitative measurements. The 3D analysis software VG Studio MAX was used to perform image analysis and assess gap formation within the tooth-restoration interface. In particular, to evaluate internal adaptation, the Defect Analysis addon module of VG Studio Max was used. Results: The data, obtained with the processing software, highlighted the presence and the shape of gaps in different colours, representing the volume of porosity within a chromatic scale in which each colour quantitatively represents a well-defined volume. Conclusion: Micro-computed tomography makes it possible to obtain several quantitative parameters, providing fundamental information on defect shape and complexity. However, this technique has the limit of not discriminating materials without radiopacity and with low or no filler content, such as dental adhesives, and hence, they are difficult to visualise through software reconstruction.

• Clinical and Experimental Vaccine Research
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• 제12권3호
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• pp.209-215
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• 2023

Purpose: The delay in acceptance or refusal to get vaccinated despite the availability of services is called vaccine hesitancy. The Global Polio Eradication Initiative in Pakistan faced consistent barriers preventing the eradication of the disease in the country. Similarly with the advent of the coronavirus disease 2019 (COVID-19) pandemic mass vaccination drives were initiated to a vaccine hesitant population. The aim of this study is to explore the prevalence and reasons for COVID-19 vaccine hesitancy in the Pakistani population. Materials and Methods: Cross-sectional study conducted during July to September 2021 using a snowball sampling technique targeting the adult population of Pakistan. The modified version of the vaccine hesitancy questionnaire related to the Strategic Advisory Group of Experts on Immunization Vaccine Hesitancy matrix was distributed online. Results: Out of 973 participants, 52.4% were immediately willing to take the vaccine and constituted the acceptance group whereas the remaining 47.6% who were still not sure formed the hesitant group. Support from leaders was found to be statistically significant for the difference between the hesitant and acceptance groups (p-value=0.027). Hesitant people were concerned about the effectiveness of the vaccine (60.9%) and potential side effects (57.9%) as it was not sufficiently tested prior to launch (44.7%). Age and education were significant factors affecting the acceptance of vaccination. The most trusted source of information regarding vaccination was health care workers (43.8%). Conclusion: A moderately high prevalence of vaccine hesitancy was reported in Pakistan. To overcome it, policymakers need to address the reasons for it. Leaders, celebrities, and healthcare workers can play an instrumental role in dispelling conspiracy theories regarding vaccines and making the vaccination drive a success.

• 대한치과교정학회지
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• 제54권2호
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• pp.89-107
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• 2024

Objective: This systematic review aimed to provide a comparative analysis of the treatment outcomes, including hard and soft tissues, postoperative stability, temporomandibular disorders (TMD), and quality of life (QoL), in patients with facial asymmetry who underwent orthognathic surgery. Methods: The primary objective was to address the question, "How do different factors related to surgery affect the outcomes and stability of orthognathic surgery in the correction of facial asymmetry?" A meta-analysis was conducted on the outcome parameters, such as skeletal, dental, and soft tissue symmetry, TMD, QoL, and relapse, using the Hartung-Knapp-Sidik-Jonkman method for random-effects models. Subgroup analyses were conducted considering surgery-related factors such as surgical techniques (one-jaw vs. two-jaw), use of the surgery-first approach, utilization of computer simulation, and analytical methods employed to evaluate asymmetry (2D vs. 3D). Results: Forty-nine articles met the inclusion criteria. The metaanalysis demonstrated a significant improvement in the symmetry of hard and soft tissues. The subgroup analysis indicated that the treatment outcomes showed significant improvement, regardless of the factors related to surgery. Changes in TMD signs and symptoms varied according to the surgical technique used. Quality of life improved in the facial, oral, and social domains. Skeletal relapse was observed during the follow-up. Conclusions: Our findings support the positive outcomes of orthognathic surgery in the treatment of facial asymmetry in terms of skeletal and soft tissue improvements, stability, relief of TMD symptoms, and enhancement of QoL. However, most of the included studies showed a low certainty of evidence and high heterogeneity.

• The Journal of Advanced Prosthodontics
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• 제16권1호
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• pp.57-65
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• 2024

PURPOSE. The aim of this stuldy was to compare the clinical marginal fit of CAD-CAM inlays obtained from intraoral digital impression or addition silicone impression techniques. MATERIALS AND METHODS. The study included 31 inlays for prosthodontics purposes of 31 patients: 15 based on intraoral digital impressions (DI group); and 16 based on a conventional impression technique (CI group). Inlays included occlusal and a non-occlusal surface. Inlays were milled in ceramic. The inlay-teeth interface was replicated by placing each inlay in its corresponding uncemented clinical preparation and taking interface impressions with silicone material from occlusal and free surfaces. Interface analysis was made using white light confocal microscopy (WLCM) (scanning area: 694 × 510 ㎛²) from the impression samples. The gap size and the inlay overextension were measured from the microscopy topographies. For analytical purposes (i.e., 95-%-confidence intervals calculations and P-value calculations), the procedure REGRESS in SUDAAN was used to account for clustering (i.e., multiple measurements). For p-value calculation, the log transformation of the dependent variables was used to normalize the distributions. RESULTS. Marginal fit values for occlusal and free surfaces were affected by the type of impression. There were no differences between surfaces (occlusal vs. free). Gap obtained for DI group was 164 ± 84 ㎛ and that for CI group was 209 ± 104 ㎛, and there were statistical differences between them (p = .041). Mean overextension values were 60 ± 59 ㎛ for DI group and 67 ± 73 ㎛ for CI group, and there were no differences between then (p = .553). CONCLUSION. Digital impression achieved inlays with higher clinical marginal fit and performed better than the conventional silicone materials.

• Journal of Yeungnam Medical Science
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• 제41권2호
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• pp.80-85
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• 2024

Background: This study aimed to compare and evaluate the marginal fit of nanocomposite computer-aided design/computer-aided manufacturing (CAD/CAM) inlays. Three types of nanocomposite CAD/CAM blocks (HASEM, VITA Enamic, and Lava Ultimate) were used as materials. Methods: Class II disto-occlusal inlay restorations were prepared on a typodont mandibular right first molar using diamond rotary instruments. The inlays were fabricated using CAD/CAM technology and evaluated using the silicone replica technique to measure marginal gaps at five locations on each inlay. The data were analyzed by two-way analysis of variance and Tukey post hoc tests (α=0.05). Results: There were no significant differences in the marginal gaps based on the type of nanocomposite CAD/CAM inlay used (p=0.209). However, there was a significant difference in the marginal gaps between the measurement regions. The gingival region consistently exhibited a larger marginal gap than the axial and occlusal regions (p<0.001). Conclusion: Within the limitations of this in vitro study, the measurement location significantly influenced the marginal fit of class II disto-occlusal inlay restorations. However, there were no significant differences in the marginal gaps among the different types of CAD/CAM blocks. Furthermore, the overall mean marginal fits of the class II disto-occlusal inlay restorations made with the three types of nanocomposite CAD/CAM blocks were within the clinically acceptable range.

• 대한치과보철학회지
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• 제54권3호
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• pp.210-217
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• 2016

목적: 본 연구의 목적은 실제 환자에서 디지털 구강스캐너로 모형 없이 제작한 보철물의 변연 및 내면 적합도를 평가하는 것이다. 대상 및 방법: 전향적 임상시험으로 시행한 본 예비 연구는 총 11개의 수복물을 대상으로 하였다. 구강스캐너(TRIOS, 3shape, Copenhagen, Denmark)로 디지털 구강인상을 채득한 후, 캐드 디자인 및 밀링 가공 과정을 통해 전부지르코니아 수복물을 제작하였다. 완성된 지르코니아관을 환자 구강 내에 시적하였고, 레플리카 술식으로 보철물-지대치 복제물을 얻었다. 이를 근원심, 협설 방향으로 잘라 변연오차, 변연간극과 축벽부, 선각부, 교합면부의 내면간극을 측정하였다. 통계처리는 Kruskal-Wallis 검정과 Mann-Whitney U 검정을 이용하여 통계적 유의성을 분석하였다(${\alpha}=.05$). 결과: 복제물을 통한 적합도 분석 결과, 근원심, 협설 절편 사이에는 통계적으로 유의한 차이가 없었다(P>.05). 변연간극에 불일치가 있었으며, 변연 오차가 변연간극 보다 컸다(P<.01). 결론: 본 연구의 한계 내에서, 구강스캐너로 모형 없이 제작한 전부지르코니아 수복물의 적합도는 임상적으로 허용할만한 결과를 보였다. 그러나 지르코니아관의 변연부위가 과풍융되는 경향이 있었으므로 주의 깊은 임상 적용 및 추적 연구가 요구된다.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제28권4호
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• pp.348-355
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• 2006

우리는 3예의 편측성 불완전 구순열 환아에서 Bardach 삼각피판법을 사용하여 구순열을 수복하였다. Millard법에 비해 비주기저부와 비익기저부에 부가적인 절개를 가하지 않으므로 술후 반흔을 줄일 수 있었다. 또한 Tennison-Randall법에 비해 간단하면서도 정교한 계측에 의한 작도가 가능하였다. 한편 삼각피판법의 단점으로 지적되고 있는 인중 부위의 술후 반흔은 3예 모두 불완전 구순열이었기 때문에 삼각피판의 길이가 짧아 심미적으로 허용할 만하였다. Bardach 삼각피판법은 편측성 불완전 구순열의 수복에 추천할 만한 술식임을 경험하였다.