• Journal of Dental Rehabilitation and Applied Science
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• v.32 no.1
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• pp.47-59
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• 2016

Purpose: The aim of this study was to investigate the changes in occlusal force after loss of the lower first molar depending on the inclination and extrusion of the adjacent and opposing teeth by using a strain gauge. Materials and Methods: Anatomic teeth were used to reconstruct the normal dental arch with loss of the lower right first molar. A uniformly thick layer of silicone was applied to the root to mimic the periodontal ligament. Four stages of dies with varying degrees of inclination and extrusion of the adjacent and opposing teeth were constructed and attached to master model interchangeably by using a CAD/CAM fabricated customized die system. The strain gauges were attached to teeth and a universal testing machine was used to determine the changes in occlusal force. An independent t-test and one-way ANOVA were performed (${\alpha}=.05$). Results: While simulating chewing food, the upper first, second premolar and lower second molar showed greater occlusal force than before extraction. When the change of adjacent teeth's occlusal force with their progressive movement after molar loss was evaluated, the difference among four die models was significant and was in the decreasing aspect (P < 0.05). Conclusion: When the lower first molar was lost and the adjacent teeth did not move yet, the occlusal force in adjacent teeth was higher than that when the lower first molar still existed. In addition, the occlusal force in the upper premolars and lower second molar decreased significantly with the progressive movement of adjacent teeth.

• Journal of the korean academy of Pediatric Dentistry
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• v.24 no.3
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• pp.543-548
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• 1997

The first permanent molar takes important place in the occlusion. Malposition of the lower first molar is frequently due to mesial migration, which is occurred by early exfoliation of the second deciduous molar or proximal caries of deciduous teeth. Above things happen without any consideration of space maintainer, prompt measures for space regaining have to be started. Especially in the case with early loss of the second deciduous molar, it has been said that there is no suitable appliance for maintaining the space before the eruption of the permanent first molar. In distalizing the upper first molar, headgears have been routinely used, which its result was definitely depended on cooperation of the patients. Nowadays, appliances such as pendulum appliances, K-loop, magnets, which can be used without cooperation of the patients, are introduced. Jones Jig, one of the molar distalizing appliances, was used on the patients who visited department of pediatric dentistry in Seoul National University Dental Hospital complaining of no eruption space for the lower second bicuspid. Either removable splint or lingal arch was used as the anchorage. Jones Jig was favorably used in the lower molar, where vestibule is shallow, and this is a case report on the satisfactory result thereof.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.45 no.5
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• pp.233-240
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• 2019

Trigeminal nerve injury as a consequence of lower third molar surgery is a notorious complication and may affect the patient in long term. Inferior alveolar nerve (IAN) and lingual nerve (LN) injury result in different degree of neurosensory deficit and also other neurological symptoms. The long term effects may include persistent sensory loss, chronic pain and depression. It is crucial to understand the pathophysiology of the nerve injury from lower third molar surgery. Surgery remains the most promising treatment in moderate-to-severe nerve injuries. There are limitations in the current treatment methods and full recovery is not commonly achievable. It is better to prevent nerve injury than to treat with unpredictable results. Coronectomy has been proved to be effective in reducing IAN injury and carries minimal long-term morbidity. New technologies, like the roles of erythropoietin and stem cell therapy, are being investigated for neuroprotection and neural regeneration. Breakthroughs in basic and translational research are required to improve the clinical outcomes of the current treatment modalities of third molar surgery-related nerve injury.

• 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.

• Journal of Korean Dental Science
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• v.3 no.1
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• pp.5-10
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• 2010

This study sought to compare the amounts of posterior anchorage loss during the en masse retraction of the upper anterior teeth between orthodontic mini-implant (OMI) and conventional anchorage reinforcement (CAR) such as headgear and/or transpalatal arch. The subjects were 52 adult female patients treated with sliding mechanics (MBT brackets, .022" slot, .019X.025" stainless steel wire, 3M-Unitek, Monrovia, CA, USA). They were allocated into Group 1 (N=24, Class I malocclusion (CI), upper and lower first premolar (UP1LP1) extraction, and CAR), Group 2 (N=15, Cl, UP1LP1 extraction and OMI), and Group 3 (N=13, Class II division 1 malocclusion, upper first and lower second premolar extraction, and OMI). Lateral cephalograms were taken before (T0) and after treatment (T1). A total of 11 anchorage variables were measured. Analysis of variance was used for statistical analysis. There was no significant difference in treatment duration and anchorage variables at T0 among the three groups. Groups 2 and 3 showed significantly larger retraction of the upper incisor edge (U1E-sag, 9.3mm:7.3mm, P<.05) and less posterior anchorage loss (U6M-sag, 0.7~0.9mm:2mm, P<.05; U6A-sag, 0.5mm:2mm, P<.01) than Group 1. The ratio of retraction amount of the upper incisor edge per 1 of anchorage loss in the upper molar made for the significant difference between Groups 1 and 2 (4.6mm:7.0mm, P<.05). Group 3 showed a relatively distal inclination of the upper molar (P<.05) and the intrusion of the upper incisor and first molar (U1E-ver, P<.05; U6F-ver, P<.05) compared to Groups 1 and 2. Although OMI could not shorten the treatment duration, it could provide better maximum posterior anchorage than CAR.

• Imaging Science in Dentistry
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• v.53 no.2
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• pp.137-144
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• 2023

Purpose: This study aimed to evaluate the anatomic circle around the impacted lower third molar to show, document, and correlate essential findings that should be included in the routine radiographic assessment protocol as clinically meaningful factors in overall case evaluation and treatment planning. Materials and Methods: Cone-beam computed tomographic images of impacted lower third molars were selected according to specific inclusion criteria. Impacted teeth were classified according to their position before assessment. The adjacent second molars were assessed for distal caries, distal bone loss, and root resorption. The fourth finding was the presence of a retromolar canal distal to the impaction. Communication with the dentist responsible for each case was done to determine whether these findings were detected or undetected by them before communication. Results: Statistically significant correlations were found between impaction position, distal bone loss, and detected distal caries associated with the adjacent second molar. The greatest percentage of undetected findings was found in the evaluation of distal bone status, followed by missed detection of the retromolar canal. Conclusion: The radiographic assessment protocol for impacted third molars should consider a step-by-step evaluation for second molars, and clinicians should be aware of the high prevalence of second molar affection in horizontal and mesioangular impactions. They also should search for the retromolar canal due to its associated clinical considerations.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.12 no.3
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• pp.42-48
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• 1990

This is a case report on an unusual - heavy buccal frenum in young lady which was treated by frenectomy, vestibuloplasty and total-palatal mucosal free graft. The authors noticed that this abnormal condition lead several chronic complications in young patient as like as premature loss of upper molar teeth, early and rapid loss of alveolar bone around insertion of frenum, over - extended eruption of lower molar teeth and abnormal mandibular movements, etc. After frenectomy and surgical extension of buccal vestiblue on both upper and lower posterior regions, we obtained a full - sized palatal mucosal graft and moved it on upper and lower extension area seperately as two pieces of free grafts to offer inherent function of denture - bearing mucogingiva and same color - matching with oral mucosa and to prevent post - operative relapse of vestibular height. We discussed here about unusual abnormality and their complications of unusual buccal frenum and its treatment.

• 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.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.22 no.1
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• pp.110-116
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• 2000

A 61-years old man with diabetes mellitus(DM) was admitted to our hospital, complaining of progressive right periorbital swelling, headache and toothache on the right lower second molar. On the first visit, moderate swelling was noticed from the right periorbital region with exophthalmos and subconjunctival effusion. Intraorally, right lower second molar had a severe periodontal disease and fistular formation on its distal area. From 3 days after hospitalization, the visual acuity of his right eye was gradually worsen and we performed CT scan. CT scan demonstrated an inflammatory change at the right orbit with subperiosteal abscess at the inferior orbital wall, which was extended from the right infratemporal, parapharyngeal and internal pterygoid space. Patient was treated by mean of intraoral(right upper vestibular and retromolar) and extraoral(infraorbital) incision and drainage, massive anti-therapy and DM control. The patient improved gradually and finally was discharged from the hospital, but his visual loss of right side was not recovered.

• The korean journal of orthodontics
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• v.14 no.1
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• pp.47-52
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• 1984

A girl aged 13 years 1 month, had a Angle's Class 1 malocclusion, characterized by severe aterior crowding, high canine, and loss of the upper and lower left first molars on account of dental caries. This patient underwent ${\frac{4}{4}}$extraction and multibonded system was used. After 20 Months, anterior crowding and high canine was corrected, and the extraction space as closed on both arch. The upper and lower left 2nd molars occupied the first molar spaces instead of the first polars. After 6 Months from debanding, band spaces were disappeared and the third molars were upting normally.