• Journal of Korean Academy of Oral and Maxillofacial Radiology
• /
• v.21 no.1
• /
• pp.7-13
• /
• 1991

An anatomic radiolucency called medial sigmoid depression can be observed on a number of panoramic and mandibular oblique lateral views in the ramus just below and anterior to the mandibular sigmoid notch. The radiolucency may be unilateral or bilateral. Seventy-eight mandibles of dry skulls were visually examined and radiographed by panoramic machine. The observable incidence, the location center, and the mean size of the medial sigmoid depression were studied. Additionally, the radiographic incidence of the depression was determined using 500 panoramic radiographs. Normal anatomic radiolucent areas in the jaws are encountered often in the radiographs taken for the usual dental practice purpose. Some of these radiolucencies can be misdiagnosed as pathologic entities. But in most cases, the size, location, and appearance of the radiolucent area, and the presence or absence of symptoms can lead one to the correct diagnosis before surgery is undertaken. And this can be secured if diagnosticians are aware of the common and varied appearances of the normal anatomic radiolucencies A depression in the ramus just below and slightly anterior to the most inferior aspect of mandibular sigmoid notch shows occasionally foramen-like or notch-like radiolucency on some panoramic and oblique lateral views. This radiolucency was named medial sigmoid depression by Langlais et a1. in 1983. Since there're no reports about this medial sigmoid depression after that, (The author retrieved the Mediline from 1983 to 1990: Cambridge scientific abstracts, (7200 Wisconsin Ave Bethesda MD 20814 U.S.A.) National Library of Medicine) the author studied the size and the location of the depression of the mandible specimens, and determined the relationship between the observable anatomic incidence and its reproducibility on the radiographs.

• Imaging Science in Dentistry
• /
• v.53 no.3
• /
• pp.193-198
• /
• 2023

Purpose: Artificial intelligence (AI) is poised to play a major role in medical diagnostics. Periodontal disease is one of the most common oral diseases. The early diagnosis of periodontal disease is essential for effective treatment and a favorable prognosis. This study aimed to assess the effectiveness of AI in diagnosing periodontal bone loss through radiographic analysis. Materials and Methods: A literature search involving 5 databases (PubMed, ScienceDirect, Scopus, Health and Medical Collection, Dentistry and Oral Sciences) was carried out. A specific combination of keywords was used to obtain the articles. The PRISMA guidelines were used to filter eligible articles. The study design, sample size, type of AI software, and the results of each eligible study were analyzed. The CASP diagnostic study checklist was used to evaluate the evidence strength score. Results: Seven articles were eligible for review according to the PRISMA guidelines. Out of the 7 eligible studies, 4 had strong CASP evidence strength scores (7-8/9). The remaining studies had intermediate CASP evidence strength scores (3.5-6.5/9). The highest area under the curve among the reported studies was 94%, the highest F1 score was 91%, and the highest specificity and sensitivity were 98.1% and 94%, respectively. Conclusion: AI-based detection of periodontal bone loss using radiographs is an efficient method. However, more clinical studies need to be conducted before this method is introduced into routine dental practice.

• Journal of The Korea Institute of Healthcare Architecture
• /
• v.23 no.4
• /
• pp.27-36
• /
• 2017

Purpose: The characteristics of spatial allocation planning in dentistry through examining the dental hospitals in Korea and comparison between them are necessary for the development of planning of the dental healthcare system. This study has been started to provide basic informations such as zoning, allocation distribution, and space configuration for the planning of dental hospital architecture. Methods: Literature review of dental care departments and investigation on current status of dental hospital in Korea have been conducted. The spatial allocation and space configuration of eleven dental hospitals have been analyzed. Results: The result of this study can be summarized in three points. The first one is that dental hospitals in Korea are consisted with eight to eleven dental care departments and they are divided with the horizontal allocation type with three to four departments in a floor for the spatial communication or the vertical allocation type with a department in each floor for the independent space. The second one is that oral medicine and oral maxillofacial radiology are located near the main entrance, orthodontics and pedodontic dentistry in lower level, prosthodontics in upper level, and conservative dentistry and periodontics have no specific spatial consideration. The third one is that the factors to consider the allocation planning are zoning for examination & diagnosis, basic practice, adolescence, surgery, circulations for patient, dentist, staff, different access for department like as easy access for reception and pedodontic dentistry, enclosure space for prosthodontics and surgery, frequency of visit and treatment care time, and change of treatment concept from treatment department to disease control corporative practice. Implications: This study is the starting point for the research of spatial configuration in dentistry and it is necessary to analyze the architectural planning to develop the dental healthcare system.

• Imaging Science in Dentistry
• /
• v.54 no.1
• /
• pp.43-48
• /
• 2024

Purpose: Oral hygiene, maintained through plaque control, helps prevent periodontal disease and dental caries. This study was conducted to examine the accuracy of plaque detection with an intraoral scanner(IOS) compared to images captured with an optical camera. Materials and Methods: To examine the effect of color tone, artificial tooth resin samples were stained red, blue, and green, after which images were acquired with a digital single-lens reflex (DSLR) camera and an IOS device. Stained surface ratios were then determined and compared. Additionally, the deviation rate of the IOS relative to the DSLR camera was computed for each color. In the clinical study, following plaque staining with red disclosing solution, the staining was captured by the DSLR and IOS devices, and the stained area on each image was measured. Results: The stained surface ratios did not differ significantly between DSLR and IOS images for any color group. Additionally, the deviation rate did not vary significantly across colors. In the clinical test, the stained plaque appeared slightly lighter in color, and the delineation of the stained areas less distinct, on the IOS compared to the DSLR images. However, the stained surface ratio was significantly higher in the IOS than in the DSLR group. Conclusion: When employing IOS with dental plaque staining, the impact of color was minimal, suggesting that the traditional red stain remains suitable for plaque detection. IOS images appeared relatively blurred and enlarged relative to the true state of the teeth, due to inferior sharpness compared to camera images.

• Imaging Science in Dentistry
• /
• v.51 no.1
• /
• pp.27-34
• /
• 2021

Purpose: This study was performed to compare the ability of limited- and large-volume cone-beam computed tomography (CBCT) to display isthmuses in the apical root canals of mandibular molars. Materials and Methods: Forty human mandibular first molars with isthmuses in the apical 3 mm of mesial roots were scanned by micro-computed tomography (micro-CT), and their thickness, area, and length were recorded. The samples were examined using 2 CBCT systems, using the smallest voxels and field of view available for each device. The Mann-Whitney, Friedman, and Dunn multiple comparison tests were performed (α=0.05). Results: The 3D Accuitomo 170 and i-Cat devices detected 77.5% and 75.0% of isthmuses, respectively (P>0.05). For length measurements, there were significant differences between micro-CT and both 3D Accuitomo 170 and i-Cat(P<0.05). Conclusion: Both CBCT systems performed similarly and did not detect isthmuses in the apical third in some cases. CBCT still does not equal the performance of micro-CT in isthmus detection, but it is nonetheless a valuable tool in endodontic practice.

• The korean journal of orthodontics
• /
• v.45 no.5
• /
• pp.253-260
• /
• 2015

Objective: The aim of this study was to evaluate the facial dimensions of young adult women with a preferred facial appearance and compare the results with those from the general population. Methods: Twenty-five linear, nine angular, and three area measurements were made and four ratios were calculated using a sample of standardized frontal and lateral photographs of 46 young adult women with a preferred facial appearance (Miss Korea group) and 44 young adult women from the general population (control group). Differences between the two groups were analyzed using multivariate analysis of variance (MANOVA). Results: Compared with the control group, the Miss Korea group exhibited a significantly greater facial height, total facial height (TFH; trichion-menton), facial width (tragus right-tragus left), facial depth (tragus-true vertical line), and trichion-nasion/TFH ratio and smaller subnasale-menton/TFH and facial width/TFH ratios. Furthermore, the control group had smaller intercanthal and interpupillary widths. Conclusions: The Miss Korea group exhibited longer, wider, and deeper faces compared with those from the general population. Furthermore, the Miss Korea group had larger eyes, longer but less protruded noses, longer and more retruded lower lips and chins, larger lip vermilion areas, and smaller labiomental angles. These results suggest that the latest trends in facial esthetics should be considered during diagnosis and treatment planning for young women with dentofacial abnormalities.

• The Journal of Advanced Prosthodontics
• /
• v.15 no.3
• /
• pp.101-113
• /
• 2023

PURPOSE. This randomized controlled trial aimed to evaluate the effect of implants' two different diameters and cantilever lengths on the marginal bone loss and stability of mplants supporting maxillary prostheses. MATERIALS AND METHODS. Ninety-six implants were placed in sixteen completely edentulous maxillary ridges. Patients were randomly divided into two groups: Group A, implants were placed with a cantilever to anterior-posterior AP spread length (CL:AP) at a ratio of 1:3; Group B, implants were placed with a CL:AP at a ratio of 1:2. Patients were further divided into four sub-groups: Groups A1, A2, B1, and B2. Groups A1 and B1 received small diameter implants while Groups A2 and B2 received standard diameter implants. Bone height and stability measurements around each implant were performed at 0, 4, 8 and 24 months after definitive prostheses delivery. RESULTS. Statistical analysis of the mean implant stability and height values revealed an insignificant difference between Group A1 and Group A2 at all the different time intervals while significantly higher values in Group B1 in comparison with Group B2. Results also showed significantly higher values in Group A1 in comparison with Group B1 and an insignificant difference between Group A2 and Group B2 at all the different time intervals. CONCLUSION. It can be concluded that the use of small diameter implants placed with a CL:AP at a ratio of 1:3 provided predictable results and that the 1:2 CL:AP significantly induced more critical bone loss in the small diameter implants group, which can significantly reduce long term success and survival of implants

• Journal of Periodontal and Implant Science
• /
• v.54 no.1
• /
• pp.3-12
• /
• 2024

Deep learning (DL) offers promising performance in computer vision tasks and is highly suitable for dental image recognition and analysis. We evaluated the accuracy of DL algorithms in identifying and classifying dental implant systems (DISs) using dental imaging. In this systematic review and meta-analysis, we explored the MEDLINE/PubMed, Scopus, Embase, and Google Scholar databases and identified studies published between January 2011 and March 2022. Studies conducted on DL approaches for DIS identification or classification were included, and the accuracy of the DL models was evaluated using panoramic and periapical radiographic images. The quality of the selected studies was assessed using QUADAS-2. This review was registered with PROSPERO (CRDCRD42022309624). From 1,293 identified records, 9 studies were included in this systematic review and meta-analysis. The DL-based implant classification accuracy was no less than 70.75% (95% confidence interval [CI], 65.6%-75.9%) and no higher than 98.19 (95% CI, 97.8%-98.5%). The weighted accuracy was calculated, and the pooled sample size was 46,645, with an overall accuracy of 92.16% (95% CI, 90.8%-93.5%). The risk of bias and applicability concerns were judged as high for most studies, mainly regarding data selection and reference standards. DL models showed high accuracy in identifying and classifying DISs using panoramic and periapical radiographic images. Therefore, DL models are promising prospects for use as decision aids and decision-making tools; however, there are limitations with respect to their application in actual clinical practice.

• The korean journal of orthodontics
• /
• v.51 no.2
• /
• pp.126-134
• /
• 2021

Objective: This study aimed to evaluate the following null hypothesis: there are no differences in the morphology of the temporomandibular joint (TMJ) structures in relation to vertical and sagittal cephalometric patterns. Methods: This retrospective study was performed with 131 participants showing no TMJ symptoms. The participants were divided into Class I, II, and III groups on the basis of their sagittal cephalometric relationships and into hyperdivergent, normodivergent, and hypodivergent groups on the basis of their vertical cephalometric relationships. The following measurements were performed using cone-beam computed tomography images and compared among the groups: condylar volume, condylar size (width, length, and height), fossa size (length and height), and condyle-to-fossa joint spaces at the anterior, superior, and posterior condylar poles. Results: The null hypothesis was rejected. The Class III group showed larger values for condylar width, condylar height, and fossa height than the Class II group (p < 0.05). Condylar volume and superior joint space in the hyperdivergent group were significantly smaller than those in the other two vertical groups (p < 0.001), whereas fossa length and height were significantly larger in the hyperdivergent group than in the other groups (p < 0.01). The hypodivergent group showed a greater condylar width than the hyperdivergent group (p < 0.01). The sagittal and vertical cephalometric patterns showed statistically significant interactions for fossa length and height. Conclusions: TMJ morphology differed across diverse skeletal cephalometric patterns. The fossa length and height were affected by the interactions of the vertical and sagittal skeletal patterns.

• The korean journal of orthodontics
• /
• v.42 no.1
• /
• pp.47-54
• /
• 2012

Objective: To determine and compare the frequency distribution of various arch shapes in ethnic Malays and Malaysian Aborigines in Peninsular Malaysia and to investigate the morphological differences of arch form between these two ethnic groups. Methods: We examined 120 ethnic Malay study models (60 maxillary, 60 mandibular) and 129 Malaysian Aboriginal study models (66 maxillary, 63 mandibular). We marked 18 buccal tips and incisor line angles on each model, and digitized them using 2-dimensional coordinate system. Dental arches were classified as square, ovoid, or tapered by printing the scanned images and superimposing Orthoform arch templates on them. Results: The most common maxillary arch shape in both ethnic groups was ovoid, as was the most common mandibular arch shape among ethnic Malay females. The rarest arch shape was square. Chi-square tests, indicated that only the distribution of the mandibular arch shape was significantly different between groups (p = 0.040). However, when compared using independent t-tests, there was no difference in the mean value of arch width between groups. Arch shape distribution was not different between genders of either ethnic group, except for the mandibular arch of ethnic Malays. Conclusions: Ethnic Malays and Malaysian Aborigines have similar dental arch dimensions and shapes.