• The korean journal of orthodontics
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• v.34 no.2 s.103
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• pp.109-119
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• 2004

This study aimed at investigating the skeletal, dentoalveolar, and soft tissue changes of Class III malocclusion cases treated by second molar extraction. The lateral cephalograms of 15 subjects with moderate Class III malocclusion by average ANB $-1.4^{\circ}\;and\;IMPA\;85^{\circ}$ were traced and the computerized superimposition of average craniofacial change was made. The data was gathered and statistically analyzed. The results were as follows: 1 Lower anterior facial height/anterior facial height increased by 0.6%(P<0.01), mandibular plane increased by $1.5^{\circ}$(P<0.05). 2. There was a slightly downward & backward rotation of the mandible. 3. Lower first molar tipped distally by 4.nm(P<0.001), lower anterior teeth lingually tipped by $3.2^{\circ}$(P<0.05). 4. Retracted lower lip improved facial profile. This study may suggest that second molar extraction could be effective for a moderate Class III malocclusion to make distalization of the lower first molar easier and avoid severe lingual tipping of the lower incisor, if the lower third molar has a normal shape, good direction of eruption and adequate time for lower second molar extraction

• The korean journal of orthodontics
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• v.24 no.3 s.46
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• pp.695-707
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• 1994

This study investigates the effects of third molar on the occlusal plane in Angle's class El malocclusion with possibilities of posterior crowding and the interrelationships of occlusal plane inclinations to other skeletal patterns. Above investigations might showed that considerations should be given to third molars with possibilities of posterior crowding in establishing diagnosis and treatment plans for Angle's class III malocclusion patients. The following conclusions were obtained 1. In events of third molars causing possible posterior crowding, maxillary third molars showed more mesial inclinations than second molars, and compared to those with third molar missing cases, first molars were more mesially inclined and displaced more inferiorly from the palatal plane and OP-MP was increase , thus the occlusal plane was less steep. 2. In events of third molars causing possible posterior crowding, the anglulation between AB line and mandibular plane was decreased and ANB showed negative values. Thus chin points were more protruded, ramus were more anteriorly displaced, and increase in lower facial height, genial angle, effective mandibular length and mandibular plane angle were observed. This in all caused more vertical opening and more severe skeletal disturbance. 3. OP-MP was increased as the maxillary first molars were more inferiorly displaced from the palatal plane. As this angle was increased mandibular planes were more inferiorly inclined and LFH, genial angle, effective mandibular length were more increased and mandibular ramus was more anteriorly placed. 4. As the maxillary first molars were more inferiorly placed from the palatal plane, more increased OP-MP/PP-MP ratio made the occlusal plane less steep. As OP-MP/PP-MP was increased, mandibular ramus was more anteriorly placed and made longer, and facial angle and effective mandibular length were increased.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.42
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• pp.4.1-4.4
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• 2020

Background: Odontogenic cysts associated with lower third molar are common. The prognosis for surgical treatment is relatively good. However, postoperative infection discourages the clinicians. Hence, we would like to investigate the factors associated with infection after surgical treatment of cysts associated with the mandibular third molar. Methods: We retrospectively reviewed the medical and radiographic records of 81 patients who were diagnosed with dentigerous cyst or odontogenic keratocyst and underwent cyst enucleation. The factors affecting postoperative infection were divided into host factor, treatment factor, and cystic lesion factor. To identify the factors associated with postoperative infection, we attempted to find out the variables with significant differences between the groups with and without infection. Results: A total of 81 patients (64 male and 17 female) were enrolled in this study. There was no statistical relationship about the postoperative infection between all variables (gender, smoking, diabetes mellitus, age, bone grafting, related tooth extraction, previous marsupialization or decompression, type of antibiotics, cortical perforation associated with cystic lesion, preoperative infection, preoperative cyst size). Conclusions: The results of this study suggest that it is not necessary to avoid bone grafts that are concerned about postoperative infection.

• Archives of Craniofacial Surgery
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• v.20 no.6
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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.

• The korean journal of orthodontics
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• v.23 no.4 s.43
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• pp.493-501
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• 1993

It is the aim of this study to determine the impacts of radicular development of lower third molars on its eruption/impaction and to grope the prediction for eruption and/or impaction in advance. Three hundred and thirty cases of orthopantomogram were employed and classified as mesial root-dominant group, distal root-dominant group and Identical group according to the radicular development of lower third molars. This presentation has carried out the incipient mesial inclination, radicular development, impaction/eruption rate and changes of mesial inclination of the very teeth. Consequently the following summary and conclusions were drawn; Radicular development dominated mesial root than the distal and dominant mesial root invited higher potentialities for normal eruption. The mesial or honzontal impactions were detected on the distal root-dominant group. This analysis has been suggested the potential eruption/impaction of lower third molars were dependent upon the radicular development and the incipient mesial inclination.

• Journal of the Korea Furniture Society
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• v.11 no.1
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• pp.53-59
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• 2000

This study was to measure formaldehyde emission and bonding strength of plywoods manufactured with urea-melamine formaldehyde adhesives, which were made from three different mixing ratios of urea and melamine, and with four different formaldehyde/urea-melamine molar ratios of 1.0,1.1,1.2 and 1.4. The results were as follows 1. Amount of formaldehyde emission was the lowest at the first method of molar ratio(F/(M+U)) 1.0. Amounts of formaldehyde emission of experimental manufactured adhesives were lower than that of commercial adhesive. 2. Bonding strength of dry specimen was the highest at the first method of molar ratio(F/(M+U)) 1.4. Dry bonding strength of molar ratio(F/(M+U)) 1.4 was similar to commercial adhesive. 3. Bonding strength of wet specimen was the highest at the second method of molar ratio(F/(M+U)) 1.4. Bonding strength of wet specimen used by the third method of molar ratio(F/(M+U)) 1.4 was almost equal to commercial adhesive.

• Journal of The Korean Dental Society of Anesthesiology
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• v.10 no.1
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• pp.27-33
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• 2010

The gag reflex is a physiologic reaction which safeguards the airway from foreign bodies. But, an exaggerated gag reflex can be a severe limitation to a patient's ability to accept dental care and for a clinician's ability to provide it. The overactive gag reflex can be due to psychological factors or physiological factors, or both. Psychological factors can include fear of loss of control and past traumatic experiences. A 58-year-old man, scheduled for extraction of left upper second molar, left lower second and third molar and implantation of left upper second molar, and left lower second molar had no specific underlying medical problems. He had exaggerated gag reflex. Dental treatment was successfully performed using intravenous sedation. Intravenous sedation with midazolam and propofol was a useful management technique for reflex control during dental treatment extended to the posterior regions in the oral cavity.

• Journal of Periodontal and Implant Science
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• v.38 no.1
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• pp.103-108
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• 2008

Purpose: Studies reported controversial results about prognosis of root resection with 0%-38% failure rate. The purpose of this study is to consider clinical efficacy of root resection. Materials and Methods: This study reported three cases of root resection which were performed on different sites. In first case, lower right first molar showed pus discharge and 7 mm of probing pocket depth. It was diagnosed as fracture of mesial root. Hemisection of mesial root was performed. In second case, upper right first molar showed severe bone loss on disto-buccal root and 7 mm of probing pocket. Resection of disto-buccal root was performed In third case, lower left second molar showed severe bone loss on distal root including apex and 15mm of probing pocket depth. Hemisection of distal root was performed. Result: In these three cases of root resection, compromised molars were treated successfully and conserved. Conclusion: Root resection is a successful procedure treating compromised multi-rooted teeth and conserving teeth when proper case selection is performed.

• The korean journal of orthodontics
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• v.49 no.3
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• pp.194-201
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• 2019

When a patient shows severe crowding, premolar extraction should be considered to provide required available space for alignment. If the third molars have already erupted and demonstrate a poor prognosis, third molar extraction and distalization of the posterior dentition can be used instead of premolar extraction to obtain space. Interproximal stripping (IPS) may also be used to gain space in cases of crowding. This case report describes the treatment of a 25-year-old man with severe crowding and mild lip protrusion. Although the crowding in the lower arch was severe enough to require first premolar extraction, distalization of the entire lower dentition with orthodontic mini-implants, extraction of the lower third molars, and IPS could successfully resolve the crowding and lip protrusion.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.41
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• pp.60.1-60.6
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• 2019

Background: The lingual nerve plays an important role in multiple functions, including gustatory sensation and contact sensitivity and thermosensitivity. Misdiagnosed conservative treatments for serious lingual nerve (LN) injuries can induce the patient to serious mental disability. After continuous observation and critical diagnosis of the injury, in cases involving significant disruption of lingual nerve function, microneurosurgical reconstruction of the nerve is recommended. Direct anastomosis of the torn nerve ends without tension is the recommended approach. However, in cases that present significant gaps between the injured nerve ends, nerve grafts or conduits (tubes of various materials) are employed. Recently, various reconstruction materials for peripheral nerves were commercially offered especially in the USA, but the best method and material is still unclear in the world. There currently exists no conventional protocol for managing LN neurosensory deficiency in regard to optimal methods and the timing for surgical repair. In Japan, the allograft collagen nerve for peripheral nerves reconstruction was permitted in 2017, and we tried to use this allograft nerve and got a recommendable result. Case presentation: This report is a long-term abandoned torn LN reconstructed with allograft nerve induced by the lower third molar extraction. Conclusions: In early sick period, with the exact diagnosis, the LN disturbance should be managed. In a serious condition, the reconstruction with allograft nerve is one of the recommendable methods.