• 대한두개안면성형외과학회지
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• 제20권6호
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• pp.376-381
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• 2019

Background: This study was conducted to determine the relationship between third molar (M3) and mandibular fracture. Methods: Patients with unilateral mandibular angle or condyle fractures between 2008 and 2018 were evaluated retrospectively. Medical records were reviewed regarding the location of fractures, and panoramic radiographs were reviewed to discern the presence and position of ipsilateral mandibular third molars (M3). We measured the bony area of the mandibular angle (area A) and the bony area occupied by the M3 (area B) to calculate the true mandibular angle bony area ratio (area A-B/area A×100). Results: The study consisted of 129 patients, of which 60 (46.5%) had angle fractures and 69 (53.5%) had condyle fractures. The risk of angle fracture was higher in the presence of M3 (odds ratio [OR], 2.2; p< 0.05) and the risk of condyle fracture was lower in the presence of M3 (OR, 0.45; p< 0.05), than in the absence of M3. The risk of angle fracture was higher in the presence of an impacted M3 (OR, 0.3; p< 0.001) and the risk of condyle fracture was lower in the presence of an impacted M3 (OR, 3.32; p< 0.001), than in the presence of a fully erupted M3. True mandibular angle bony area ratio was significantly lower in the angle fractures than in the condyle fractures (p= 0.003). Conclusion: Angle fractures had significantly lower true mandibular angle bony area ratios than condyle fractures. True mandibular angle bony area ratio, a simple and inexpensive method, could be an option to predict the mandibular fracture patterns.

• 구강회복응용과학지
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• 제26권4호
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• pp.463-476
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• 2010

다수의 구치 상실로 인한 구치부 지지의 부족은 일차적으로 대합치의 정출 및 잔존치의 과도한 교합하중을 발생시킨다. 대합치의 정출은 교합평면의 부조화(reverse curve)와 보철수복공간의 부족을 일으킬 수 있다. 잔존치의 과도한 교합하중 역시 전치의 전방돌출이나, 잔존치의 급속한 마모를 일으켜 적절한 전방유도의 상실 및 교합의 부조화, 보철수복공간의 부족을 일으킬 수 있다. 이러한 환자의 경우, 치과의사는 현재의 교합수직고경이 적절한지의 여부를 판단한 후, 환자가 적응할 수 있는 범위 내에서 기능적, 심미적인 수직고경을 정하고, 반복재현 가능한 하악위에서 적절한 전방유도와 교합평면을 설정해야 한다. 본 증례에서는 구치부 상실 및 대합치의 정출, 그리고 잔존치의 심한 마모로 인하여 교합수직고경 및 교합평면이 붕괴된 환자의 완전구강회복 증례를 문헌 고찰과 함께 보고하고자 한다.

• 대한치과교정학회지
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• 제50권2호
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• pp.86-97
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• 2020

Objective: To propose a three-dimensional (3D) method for evaluating temporomandibular joint (TMJ) changes during Twin-block treatment. Methods: Seventeen patients with Class II division 1 malocclusion treated using Twin-block and nine untreated patients with a similar malocclusion were included in this research. We collected their cone beam computed tomography (CBCT) data from before and 8 months after treatment. Segmentations were constructed using ITK-SNAP. Condylar volume and superficial area were measured using 3D Slicer. The 3D landmarks were identified on CBCT images by using Dolphin software to assess the condylar positional relationship. 3D models of the mandible and glenoid fossa of the patients were constructed and registered via voxel-based superimposition using 3D Slicer. Thereafter, skeletal changes could be visualized using 3DMeshMetric in any direction of the superimposition on a color-coded map. All the superimpositions were measured using the same scale on the distance color-coded map, in which red color represents overgrowth and blue color represents resorption. Results: Significant differences were observed in condylar volume, superficial area, and condylar position in both groups after 8 months. Compared with the control group (CG), the Twin-block group exhibited more obvious condyle-fossa modifications and joint positional changes. Moreover, on the color-coded map, more obvious condyle-fossa modifications could be observed in the posterior and superior directions in the Twin-block group than in the CG. Conclusions: We successfully established a 3D method for measuring and evaluating TMJ changes caused by Twin-block treatment. The treatment produced a larger condylar size and caused condylar positional changes.

• 대한치과교정학회지
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• 제50권2호
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• pp.129-135
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• 2020

Objective: This study aimed to evaluate the immediate effects of mandibular posterior displacement on the pharyngeal airway space (PAS) by using cephalometric evaluations and to investigate how the surrounding structures are schematically involved. Methods: In this retrospective study, 38 subjects with functional Class III malocclusion and two lateral cephalograms were selected. The first lateral cephalogram was taken with the mandible in the habitual occlusal position, and the second in anterior edge-to-edge bite. Paired t-test was used to analyze changes in the PAS, hyoid bone, tongue, and soft palate, followed by mandibular posterior displacement. Pearson's correlation analysis was used to determine the relationship between the amount of mandibular posterior displacement and other variables. Results: A statistically significant decrease was observed in the PAS following mandibular posterior displacement. Along with mandibular posterior displacement, the tongue decreased in length (p < 0.001) and increased in height (p < 0.05), while the soft palate increased in length, decreased in thickness, and was posteriorly displaced (p < 0.001). The hyoid bone was also posteriorly displaced (p < 0.05). There was no correlation between the amount of mandibular posterior displacement and the measured variables. Conclusions: The PAS showed a statistically significant decrease following mandibular posterior displacement, which was a consequence of retraction of the surrounding structures. However, there were individual variances between the amount of mandibular posterior displacement and the measured variables.

• Journal of Oral Medicine and Pain
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• 제17권2호
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• pp.63-73
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• 1992

This study was performed for the purpose of investigating the relation between width of temporomandibular joint space and craniofacial morphology in patients with CMDs. The subjects utilized here were aged from 16 to 63 years old and 19 male and 46 female. For the study, each patient was taken radiographs by Transcranial and Lateral Cephalographic projection and the films were traced with routine method. The measured items were anterior, superior, posterior joint space and relative condylar position to the deepest part of glenoid fossa in Transcranial film and items related vertical and/or horizontal growth in Cephalogram. The data were processed with SPSS/PC+ package for statistical analysis. The obtained results were as follows : 1. Anterior joint space in affected side were wider than that of unaffected side, but for superior and posterior joint space, the value of unaffected side were more than those of affected side. 2. Superior or posterior joint space of affected side were significantly correlated with items related vertical growth, such as ramus height, Jarabak ratio, FMA. From this, the following cold be proposed, the wider the joint space of superior or posterior aspect of affected side was, the more the patient showed growth pattern of counter clockwise. 3. Superior or posterior joint space of affected side were significantly correlated with items related horizontal growth, such as SNPo, NAPo, APDI and ANB. From this the following could be proposed, the wider the joint space of superior or posterior aspect of affected side was, the more the patient showed anterior displacement of mandible. 4. It would be proposed that the diagnositic value of superior and posterior joint space of affected side in transcranial radiograph was excellent.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제37권1호
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• pp.21-29
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• 2011

Introduction: To compare the change in frontal ramal inclination (FRI) in laterognathism after orthognathic surgery. Materials and Methods: Twenty four patients (10 men, 14 women; mean age, $22.8{\pm}5.2$ years) with minimal facial canting (${\leq}$ 2 mm) and apparent menton deviation ($5.9{\pm}2.4\;mm$) who had been operated on to correct facial asymmetry and skeletal CIII malocclusion, were selected. On a preoperative posteroanterior (PA) cephalogram, the FRI of the deviated side and non deviated side, L1 deviation amounts and menton deviation amounts were measured. The FRI differences between both sides were compared, and the correlations between the measured deviated elements and the FRI differences were analyzed. On a postoperative PA cephalogram, the shifting amount of L1, shifting amount of L7 and FRI of both sides were measured, and the correlations between the shifting elements and the change in FRI were analyzed. Results: On the preoperative PA cephalogram, the FRI of the non deviated side was significantly greater than those of the deviated side. The differences in FRI, with a menton deviation amount showed a significant correlation. On the postoperative PA cephalogram, the FRI differences between the deviated and non deviated side were decreased significantly and mandibular transverse movement toward central position was noted. The mean shifting amounts of L7 were associated with the amount of change in the deviated side of FRI. Conclusion: Transverse shifting of the mandible through orthognathic surgery decreases the FRI difference, which showed laterognathism, and improves the facial contour.

• Imaging Science in Dentistry
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• 제34권3호
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• pp.129-136
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• 2004

Purpose: To evaluate whether cone beam computed tomography can depict the distribution, position, frequency, relative vertical dimension, and the diameter of the lingual foramen and direction of lingual bone canal. Materials and Methods : Cone beam computed tomography of mandible was performed on 25 males and 25 females with no history of any orthodontic treatments or any other dental surgeries. A statistical comparison was done on the mean values of males and females. Results: In the location and distribution of lingual foramina, median lingual foramen was found in all subjects and lateral lingual foramen in 58%. In the lateral lingual foramen, bilateral type was found in 28% and unilateral type in 30%. In the number of lingual foramina, median lingual foramen had two foramina and lateral lingual foramen had one foramen, mostly. In the relative mean vertical dimension of lingual foramina, median lingual foramen was 0.03±0.08, and both lateral lingual foramina was 0.20±0.04. The mean diameter of lingual foramina, median lingual foramen was 0.9mm±0.28, right lateral lingual foramen was 0.92mm±0.23, and left lateral lingual foramen was 0.88mm±0.27. The most frequent direction of the lingual bone canals, median lingual bone canal proceeded in anteroinferior direction and lateral lingual bone canal in anterosuperolateral direction. Conclusion : Cone beam computed tomography can be helpful for surgery and implantation on the mandibular area. Radiologist should be aware of this anatomical feature and its possible implications.

• Journal of Korean Dental Science
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• 제7권2호
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• pp.66-79
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• 2014

Purpose: To analyze the amount and pattern of tooth movement and the changes in arch dimension of mandibular dentition after orthodontic treatment using a new three-dimensional (3D)-indirect superimposition method. Materials and Methods: The samples consisted of fifteen adult patients with class I bialveolar protrusion and minimal anterior crowding, treated by extraction of four first premolars with conventional sliding mechanics. After superimposition of 3D-virtual maxillary models before and after treatment using best-fit method, 3D-virtual mandibular model at each stage was placed into a common coordinate of superimposition using 3D-bite information, which resulted in 3D-indirect superimposition for mandibular dentition. The changes in mandibular dental and arch dimensional variables were measured with Rapidform 2006 (INUS Technology). Paired t-test was used for statistical analysis. Result: The anterior teeth moved backward, displaced laterally, and inclined lingually. The posterior teeth showed statistically significant contraction toward midsagittal plane. The amounts of backward movement of anterior teeth and forward movement of posterior teeth showed a ratio of 6 : 1. Although the inter-canine width increased slightly (0.8 mm, P<0.05), the inter-second premolar, inter-first molar, and inter-second molar widths decreased significantly with similar amounts (2.2 mm, P<0.05; 2.3 mm, P<0.01; 2.3 mm, P<0.001). The molar depth decreased (6.7 mm, P<0.001) but canine depth did not change. Conclusion: A new 3D-indirect superimposition of the mandibular dentitions using best-fit method and 3D-bite information can present a guideline for virtual treatment planning in terms of tooth position and arch dimension.

• Journal of Dental Anesthesia and Pain Medicine
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• 제16권2호
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• pp.111-116
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• 2016

Background: Inferior alveolar nerve block (IANB) of the mandible is commonly used in the oral cavity as an anesthetic technique for dental procedures. This study evaluated the success rate of the first IANB administered by dental practitioners. Methods: Volunteer dental practitioners at Mahidol University who had never performed an INAB carried out 106 INAB procedures. The practitioners were divided into 12 groups with their advisors by randomized control trials. We recorded the success rate via pain visual analog scale (VAS) scores. Results: A large percentage of the dental practitioners (85.26%) used the standard method to locate the anatomical landmarks, injecting the local anesthetic at the correct position, with the barrel of the syringe parallel to the occlusal plane of the mandibular teeth. Further, 68.42% of the dental practitioners injected the local anesthetic on the right side by using the left index finger for retraction. The onset time was approximately 0-5 mins for nearly half of the dental practitioners (47.37% for subjective onset and 43.16% for objective onset), while the duration of the IANB was approximately 240-300 minutes (36.84%) after the initiation of numbness. Moreover, the VAS pain scores were $2.5{\pm}1.85$ and $2.1{\pm}1.8$ while injecting and delivering local anesthesia, respectively. Conclusions: The only recorded factor that affected the success of the local anesthetic was the administering practitioner. This reinforces the notion that local anesthesia administration is a technique-sensitive procedure.

• 대한치과교정학회지
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• 제45권3호
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• pp.121-129
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• 2015

Objective: This study aimed to assess three-dimensional changes in the temporomandibular joint positions and mandibular dimensions after correction of dental factors restricting mandibular growth in patients with Class II division 1 or division 2 malocclusion in the pubertal growth period. Methods: This prospective clinical study included 14 patients each with Class II division 1 (group I) and Class II division 2 (group II) malocclusions. The quad-helix was used for maxillary expansion, while utility arches were used for intrusion (group I) or protrusion and intrusion (group II) of the maxillary incisors. After approximately 2 months of treatment, an adequate maxillary arch width and acceptable maxillary incisor inclination were obtained. The patients were followed for an average of 6 months. Intraoral and extraoral photographs, plaster models, and cone-beam computed tomography (CBCT) images were obtained before and after treatment. Lateral cephalometric and temporomandibular joint measurements were made from the CBCT images. Results: The mandibular dimensions increased in both groups, although mandibular positional changes were also found in group II. There were no differences in the condylar position within the mandibular fossa or the condylar dimensions. The mandibular fossa depth and condylar positions were symmetrical at treatment initiation and completion. Conclusions: Class II malocclusion can be partially corrected by achieving an ideal maxillary arch form, particularly in patients with Class II division 2 malocclusion. Restrictions of the mandible in the transverse or sagittal plane do not affect the temporomandibular joint positions in these patients because of the high adaptability of this joint.