• 대한두개안면성형외과학회지
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• 제19권3호
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• pp.190-193
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• 2018

Background: This study was conducted to determine the effect of the distributional relationship between dental roots and the mandibular bone on single mandibular bone fractures, which are common craniofacial fractures. Methods: This was a retrospective, single-center study in Seoul, Korea. Patients with single mandibular fractures in the symphysis, parasymphysis, body, and angle area, with tooth structure involvement were included. The control group included patients with simple, bone-level lacerations without fractures. In total, 94 patients (72 males and 22 females) were included in the treatment group, and 125 (71 males and 54 females) were included in the control group. The height of the mandibular bone and the dental root were measured with panoramic radiography. The central incisor represented the symphysis area, the canine represented the parasymphysis area, the first molar represented the body area, and the second molar represented the angle area. Results: In the treatment group, symphysis fractures occurred in 16 patients (17%), parasymphysis fractures in 36 patients (38%), body fractures in 17 patients (18%), and angle fractures in 25 patients (27%). The ratios of the dental roots to the total height of the mandibular bone in the treatment group were 30.35%, 39.75%, 39.53%, and 36.27% for symphysis, parasymphysis, body, and angle areas, respectively, whereas in the control group, they were 27.73%, 39.70%, 36.76%, and 35.48%. The ratios of the treatment group were significantly higher than those of the control group. Conclusion: The results show that the higher ratio of the dental root to the height of the mandibular bone increases the fracture risk.

• 치과방사선
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• 제22권1호
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• pp.7-22
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• 1992

The stress distributions on a human mandible for 18 load cases under two different boundary conditions (mouth open and closed), using the three dimensional finite element modeling were studied. Also, the expected fracture loads for each load cases were calculated by using the Von-Mises yield criterion. The model of a mandible with all teeth was composed of 2402 hexahedron elements and 3698 nodes. CAD techniques were used to analyze the 3-dimensional results. The conclusions of this study were as follows: 1. In the mouth open state, the maximum stress occured at the condyle neck; when the lateral load was exerted, the maximum stress occured at the load side condyle. 2. In the mouth closed state, when the loads were exerted on the mandibular body and chin, the maximum stress occured at the loaded area, and when the loads were exerted on the angle and ramus, the maximum stress occured at the condyle neck. 3. The expected fracture loads in each load case were calculated using the Von-Mises yield criterion, and it was confirmed that the mandible in the mouth open state was more easily fractured than that in the mouth closed state, and the expected fracture loads are lesser in the cases that load direction is parallel at mandibular plane than 45°. 4. The magnitudes of the expected fracture loads increased in the order of angle, ramus, body and chin in case of the mouth closed state, while chin, body, angle and ramus in case of the mouth open state. 5. The Von-Mises stress concentration regions analyzed by F.E.M. corresponded well with the results of clinical studies.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제18권3호
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• pp.470-487
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• 1996

The purpose of this study was to investigate the dynamic response of the mandible to impact and provide insight into the fracture mechanism of the mandible, by 3-dimensional finite element method. The finite element model of the mandible was developed and calculated using NASTRAN/XL (MSC co. U.S.A.) and the linear dynamic transient analysis was performed according to the impulsive force direction, force type and impulse time to the mandible. At first, the load was applied on the mandibular symphysis, body, angle and subcondylar area in the horizontal mandibular plane and the computed stress-time histories at 14 locations of the mandible were obtained. Secondly, the impulsive force was directed to the symphyseal area with changing the force magnitude and impulse time, and calculated the node displacement at 8 locations of mandible. The conclusions from from this study were as follows. 1. The appearance of impulsive energy transmission was different to the direction of impulse to the mandible. 2. The impulsive stress and deformation were larger in lingual or medial side than buccal or lateral in the mandible. 3. The velocity, appearance of energy transmission and the fracture pattern in mandible were affected rather impulse time than force. 4. The horizontal impact to the one side of mandible did not have effect on the stress and displacement of contralateral mandible. From the above results, fracture pattern in symphysis can be showed as simple or comminuted, multiple or associated in body and angle and solitary in subcondyle area.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제29권1호
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• pp.50-54
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• 2007

This report constitutes a 7-year study of facial fractures based on a series of 616 patients who were treated for facial fractures as in-patients at Chosun University Dental Hospital between 1998 and April 2005. The following results were obtained : 1. The ratio of men to women was 5 : 1. 2. The major etiological factors were falls (36.2%), traffic accidents (23.4%), punches (18.1%), sports (8.3%), and accidents related to work (2.8%). 3. They were most frequent in the second (28.8%), first (26.6%), and third (12.3) decades, in that order. 4. The sites of frequent mandible fracture are the symphysis (32%), left mandibular angle (25.3%), and right mandibular angle (10.9%). 5. The most frequent maxillary fractures were zygomatic fractures (46.4%), Le Fort I fractures (28.8%), and Le Fort II (12.0%) fractures.

• Journal of Dental Anesthesia and Pain Medicine
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• 제18권3호
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• pp.183-187
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• 2018

Complex cervical spine fractures are a serious complications of maxillofacial trauma and associated with high mortality and neurological morbidity. Strict vigilance in preventing further insult to the cervical spine is a crucial step in managing patients who are at risk for neurologic compromise. We report a rare case of a right transverse process of atlas fracture with right-sided vertebral artery injury that was associated with a comminuted fracture of the body and angle of the mandible, which restricted mouth opening. Airway management was performed by an awake fiber-optic nasotracheal intubation, where neck movement was avoided with a cervical collar. Vertebral artery injuries may have disastrous consequences, such as basilar territory infarction and death, and should be suspected in patients with head and neck trauma. After mandibular plating, the patient was on cervical collar immobilization for 12 weeks and anti-coagulant therapy.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제40권6호
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• pp.285-290
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• 2014

Objectives: We compared resorbable plates with titanium plates for treatment of combined mandibular angle and symphyseal fractures. Materials and Methods: Patients with mandibular angle and symphysis fractures were divided into two groups. The control (T) group received titanium plates while the experimental (R) group received resorbable plates. All procedures were carried out under general anesthesia using standard surgical techniques. We compared the frequency of wound dehiscence, development of infection, malocclusion, malunion, screw breakage, and any other technical difficulties between the two groups. Results: Thirteen patients were included in the R group, where 39 resorbable plates were applied. The T group consisted of 16 patients who received 48 titanium plates. The mean age in the R and T groups was 28.29 and 24.23 years, respectively. Primary healing of the fractured mandible was obtained in all patients in both groups. Postoperative complications were minor and transient. Moreover, there were no significant differences in the rates of various complications between the two groups. Breakage of 3 screws during the perioperative period was seen in the R group, while no screws or plates were broken in the T group. Conclusion: Resorbable plates can be used to stabilize combined mandibular angle and symphysis fractures.

• The Journal of Advanced Prosthodontics
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• 제11권3호
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• pp.187-192
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• 2019

PURPOSE. The purpose of this in vitro study was to investigate the fracture loads and modes of failure for the full range of natural teeth under simulated occlusal loading. MATERIALS AND METHODS. One hundred and forty natural teeth were taken from mandibles and maxillas of patients. There were 14 groups of teeth with 10 teeth in each group (5 males and 5 females). Each specimen was embedded in resin and mounted on a positioning jig, with the long axis of the tooth at an inclined angle of 30 degrees. A universal testing machine was used to measure the compression load at which fracture of the tooth specimen occurred; loads were applied on the incisal edge and/or functional cusp. RESULTS. The mean fracture load for the mandibular first premolar was the highest (2002 N) of all the types of teeth, while the mean fracture load for the maxillary first premolar was the lowest (525 N). Mean fracture loads for the mandibular and maxillary incisors, and the first and second maxillary premolars, had significantly lower values compared to the other types of teeth. The mean fracture load for the teeth from males was significantly greater than that for the teeth from females. There was an inverse relationship between age and mean fracture load, in which older teeth had lower fracture loads compared to younger teeth. CONCLUSION. The mean fracture loads for natural teeth were significantly different, with dependence on tooth position and the sex and age of the individual.

• 대한치과기공학회지
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• 제42권2호
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• pp.129-137
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• 2020

Purpose: The aim of this study is to observe the compressive fracture strength of the crown according to the direction of the occlusal force of the mandibular canine and carnassial of the small dog. Methods: The abutment models of mandibular canine and carnassial were prepared, specimens of zirconia, PMMA and Ni-Cr alloy were produced. The experimental jig was fabricated with Co-Cr alloy and buried in acrylic resin after make tilt to specified angle. The specimen was attached to a jig and loaded using a universal testing machine until the specimen fractured. Results: The compressive fracture strengths of CXZ and CXP specimens were found to be 999.21 ± 31.15 N on average and 731.42 ± 59.13 N on average. And CZZ and CZP specimens were 730.48 ± 70.14 N on average and 377.65 ± 11.87 N on average. CXN and CZN specimens were not fractured. In addition, MZZ and MZP specimens were 746.46 ± 50.75 N and 258.64 ± 31.86 N on average. The MZN specimens were not fractured. Conclusion: Zirconia has compressive fracture strength that can be applied to small dog's canine and Carnassial prosthetics, while PMMA has inadequate strength to small dog's carnassial prosthesis.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제13권2호
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• pp.137-143
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• 1991

악안면부의 기형은 기능 및 심미적인 매우 중요한 문제이며, 이러한 면에서 현대 악안면 영역의 성형술은 기능 및 사회심리적으로 많은 기여를 한다는 것은 사실이다. 악안면 성형술 중 하악 우각부에 대한 관심은 19 세기 후반부터 교근비대증 (Masseter Hypertrophy)으로 표현되었으며, 안모의 심미적인 영향에 대한 평가는 동양에서 하악골의 변형과 함께 비중있게 다루어지고 있다. 교근비대 또는 협부비대의 원인은 악성 및 양성종물, 악습관에 의한 생리적 비대, 감염, 선천적기형 등이 있을 수 있으나, 환자가 호소하는 주소는 안연의 비대칭 또는 사각형의 안모등이므로 이에 대한 수술의 주된 목적은 심미적인 면이 대부분을 차지한다고 볼 수 있다. 그러므로 안모개선 등 수술 후의 결과에 대한 깊은 관심이 요구되며, 따라서 혈종이나 감염, 하악골 골절, 개구장애 등과 같은 합병증과 후유증에 대한 올바른 이해와 최대한의 예방이 필요할 것으로 사료되어 문헌고찰과 함께 증례보고를 하는 바이다.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제17권3호
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• pp.277-282
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• 1995

With the use of antibiotics and improved dental care, osteomyelitis of the jaw is less common these days, But sometimes the management of osteomyelitis is more difficult because of appearance of resistant organisms to antibiotics. Treatment of the steomyelitis are incision and drainage, closed catheter irrigations, sequestrectomy, saucerization, hyperbaric ocygen therapy, and resection with or without bone graft. We experienced advanced osteomyelitis due to delayed treatment of left mandibular angle fracture. He have medical history of pschysoprenia. We decided to treat the patient with open reduction and closed cather irrigation. We achived reconsolidation of mandibular fracture accompanied by osteomyelitis by complete removal of inflammatory tissues, rigid fixation with miniplate and closed catheter irrigation.