• Journal of the korean academy of Pediatric Dentistry
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• v.25 no.4
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• pp.717-730
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• 1998

The Finite Element Analysis has been used for stress analysis of prosthesis, orthodontic or orthopedic appliances and filling materials. The primary purpose of the present studying was to evaluate the effectiveness of needle post in promoting the retention and integrity of composite crown restored on the pulpotomized primary central incisor. Three finite element models-natural tooth (Sample I), composite crown with (Sample II) and without (Sample III) needle post-were constructed and the stress distribution within each model were analyzed and compared one another. The results can be summarized as follows: 1. In sample I, the stress was shown to have distributed uniformly throughout the whole tooth even to the alveolar bone. 2. In sample II, the transmission of stress from the crown to the root area was shown to be very poor and irregular. 3. In sample III, the needle post was proved to be very effective in distributing the stress well to the aveolar bone which might help in maintaining the stability of crown restoration.

• Restorative Dentistry and Endodontics
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• v.44 no.3
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• pp.29.1-29.7
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• 2019

Endodontic microsurgery is defined as the treatment performed on the root apices of an infected tooth, which was unresolved with conventional root canal therapy. Recently, the advanced technology in 3-dimensional model reconstruction based on computed tomography such as cone beam computed tomography has opened a new avenue in application of personalized, accurate diagnosis and has been increasingly used in the field of dentistry. Nevertheless, direct intra-oral localization of root apex based on the 3-dimensional information is extremely difficult and significant amount of bone removal is inevitable when freehand surgical procedure was employed. Moreover, gingival flap and alveolar bone fenestration are usually required, which leads to prolonged time of surgery, thereby increasing the chance of trauma as well as the risk of infection. The purpose of this case report is to present endodontic microsurgery using the guide template that can accurately target the position of apex for the treatment of an anterior tooth with calcified canal which was untreatable with conventional root canal therapy and unable to track the position of the apex due to the absence of fistula.

• The Journal of the Korean dental association
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• v.50 no.12
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• pp.763-770
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• 2012

The purposes of this work were to assess the cognition of the registered nurse(RN) on oral and maxillofacial emergency treatment and to compare cognition of the RN with that of the 119 emergency medical technician(EMT). 450 RNs who were working at each of secondary hospitals in Jeju province had responded to the questionnaire. Independent sample t-test and chi-square test were used to assess the state of RN on dental emergency treatment and to compare RN with EMT. The question 'education time on dentistry in formal education' that marked '0 hour' and '1-3 hours' were 73.3% and 20.0%, respectively. The question 'refresher training class on dentistry' that marked '0 hour' and '1-3 hours' were 92.9% and 6.7%, aggregately 99.6%. The results showed low score in the question 'reduction of temporo-mandibular joint(TMJ)'($1.67{\pm}0.857$), 'fixation of dislocated TMJ'($1.70{\pm}0.853$) and 'post-avulsed tooth treatment'($1.78{\pm}0.774$) by 5-point Likert scale. Likewise, the scores were $2.02{\pm}0.806$ in the question 'treatment of maxillofacial trauma', $2.76{\pm}1.061$ in the question 'emergent care of avulsed tooth', $2.70{\pm}1.095$ in the question 'treatment time of avulsed tooth' and $2.79{\pm}1.056$ in the question 'mouth guard', respectively. Compared to EMT, results of RN showed a statistically lower figure(p<0.05) in all items compared except the question 'medicine control', and the question 'doctor care in emergency room' was borderline(p=0.069). From this study, it is necessary for RN and student of nursing science to be educated on the oral and maxillofacial emergency treatment for the initial management of injuries. Authors suggest further co-study and nation-wide research with nursing care.

• Journal of the korean academy of Pediatric Dentistry
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• v.34 no.1
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• pp.162-168
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• 2007

Impaction of the maxillary central incisor may cause social, esthetic, and functional problems in children. There are various means of treatment for the inverted maxillary central incisor, such as extraction, surgical opening followed by orthodontic traction surgical repositioning or intra-alveolar autotransplantation prior to extraction. In this case, we surgically repositioned the inverted maxillary central incisor to normal semi-erupted position in a 5-year-old boy The developmental stage of the inverted tooth was Nolla's 6.5, which indicates formation of less than one third of the root. After surgical reposition, we did follow-up for 21 months, expecting spontaneous growth Unfortunately, poor prognosis was noted further root was not observed. Such failure seems to originate from possible injury on Hertwig's epithelial root sheath by surgical trauma. We performed surgical repositioning to retain the tooth instead of extraction. However, arrest of root development occurred which is one of the critical complications. In order to increase the success rate of the surgical reposition procedure, minimal surgical trauma is required as well as selection of adequate indication and decision of proper time of treatment considering the stage of root development.

• Journal of Dental Rehabilitation and Applied Science
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• v.27 no.4
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• pp.423-436
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• 2011

Trauma from occlusion (TFO) is a pathologic alterations which develop in the periodontium as a result of undue masticatory force. The purpose of this article is to review the controversies about TFO. There are evidences that TFO is a risk factor in the progression of periodontitis. Tooth mobility should be reduced by selective occlusal adjustment. TFO can be developed dependent on the masticatory pattern, occlusion and anterior overbite in sound periodontal conditions. Secondary TFO may aggravate unstable occlusion. If "loss of posterior support" was occur, the problems were worsen. Extrusion, migration, rotation and pathologic deviation can be resulted. Opposite contention is the "shortened dental arch" concept. However, these two concepts persue the occlusal stability together. To treat TFO adequately, exact diagnosis and multi-disciplinary treatment should be needed.

• Journal of the korean academy of Pediatric Dentistry
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• v.40 no.2
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• pp.127-132
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• 2013

Traumatic injuries to immature permanent teeth are common and the results can be destructive. Although Hertwig's epithelial root sheath is usually sensitive to trauma, it may resist damage from trauma thereby retaining its vitality and continuing to calcify a root under favorable conditions. This case report describes two cases of trauma to immature permanent incisors. The first case presents an avulsed maxillary central incisor which has been replanted. The other case shows completely avulsed mandibular central incisors which have not been replanted. However, both cases subsequently show continued growing roots separated from the main roots. This report highlights the ability of the immature pulp tissue to continue to form dentin and the robustness of Hertwig's epithelial root sheath to initiate root development despite a traumatic injury.

• Journal of the korean academy of Pediatric Dentistry
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• v.32 no.3
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• pp.550-556
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• 2005

Tooth impaction is defined as a cessation of the eruption of a tooth at the level of the oral mucosa or alveolar bone by any causes. Any tooth in the dental arch can be impacted, but the teeth frequently involved in a descending order are the mandibular and maxillary third molars, the maxillary canines, the mandibular and maxillary second premolars, and the maxillary central incisors. In these teeth, impaction of maxillary incisor occurs in about 0.1-0.5% and major causes are trauma, supernumerary teeth and periapical inflammation of primary maxillary incisor. Delayed eruption of a maxillary central incisor results in midline shift, the space's being occupied by an adjacent tooth and different levels of alveolar height. Treatment options are observation, surgical intervention, surgical exposure and orthodontic traction, transplantation and extraction. These cases were about the patients with delayed eruption of maxillary central incisor. We surgically exposed impacted tooth and guided it into normal position by the orthodontic traction. At the completion of traction, the maxillary central incisor was positoned fairly within the arch and complications such as root resorption were not observed.

• Restorative Dentistry and Endodontics
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• v.39 no.2
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• pp.137-142
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• 2014

This article presents the successful surgical management of a failed mineral trioxide aggregate (MTA) orthograde obturation of a tooth with a history of impact trauma and perforated internal root resorption. A symptomatic maxillary lateral incisor with a history of perforation due to internal root resorption and nonsurgical repair using MTA was referred. Unintentional overfill of the defect with MTA had occurred 4 yr before the initial visit. The excess MTA had since disappeared, and a radiolucent lesion adjacent to the perforation site was evident radiographically. Surgical endodontic retreatment was performed using calcium enriched mixture (CEM) cement as a repair material. Histological examination of the lesion revealed granulation tissue with chronic inflammation, and small fragments of MTA encapsulated within fibroconnective tissue. At the one and two year follow up exams, all signs and symptoms of disease had resolved and the tooth was functional. Complete radiographic healing of the lesion was observed two years after the initial visit. This case report illustrates how the selection of an appropriate approach to treatment of a perforation can affect the long term prognosis of a tooth. In addition, extrusion of MTA into a periradicular lesion should be avoided.

• Journal of the korean academy of Pediatric Dentistry
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• v.26 no.1
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• pp.146-150
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• 1999

With the improved cure rates for childhood malignant conditions in the past decade, late effects of cancer therapy must be recognized to minimize their impact on the quality of life in long-term survivors. Chemoradiation therapy is a major part of pediatric oncology treatment and is implicated in causing tooth agenesis, microdontia, root shortening, early apical closure, and coronal hypocalcification. Dental development may be affected by illness, trauma, chemotherapy, or radiation therapy at any point prior to complete maturation. Treatment given during the first 3.5 years of life was more likely to affect the dental lamina and crown formation and result in a small tooth. Dental treatment affected by chemoradiation damage to developing teeth includes orthodontic tooth movement, prosthetic abutment consideration, periodontal health, space maintenance, requirement for home fluoride regimens to protect hypomineralized teeth, and enodontic procedures. Dental abnormalities are common in patients treated for cancer, and these children require aggressive dental follow-up. Meticulous surveillance may facilitate detection of abnormalities, enabling the dental practitioner to intervene earlier in promoting a more aggressive regimen of oral care, thus reducing the morbidity associated with dental sequelae of oncotherapy, specifically periodontal disease and malocclusion. In this case, we report microdontia of all permanent second premolar and second molar in an 8 year old boy treated with chemotherapeutic agents during period of active dental development(14 months to 38 months of age).

• The Journal of the Korean dental association
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• v.54 no.5
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• pp.365-373
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• 2016

Purpose: Cemental tear is a specific type of root surface fracture characterized by a complete separation of a cemental fragment along the cementodentinal junction or a partial split within the cementum along an incremental line. It is suggested to be a factor for periodontal or periapical tissue destruction. The aim of this study is to present a diagnosis and treatment of cemental tear associated with periapical lesion with root canal treatment and regenerative periodontal surgery. Treatments: A 60-year-old male who had a history of sports trauma on the mandibular right central incisor about 10 years ago presented with apical cemental tear. Clinical examination showed a slightly dark yellowish discoloration and sinus tract that was located on the apical labial mucosa. The mobility and percussion were also assessed on the diseased tooth and recorded as $Miller^{\circ}{\phi}s$ Class II and tenderness to percussion. The probing depth was within the normal limit (<3 mm). Radiographic examination revealed a radiolucent lesion at the apical area and extended to distal aspect of the tooth along the fragment of cemental tear. After root canal treatment, periapical surgery was performed. The bony defect was exposed and then the detached root fragment was removed. Apical root resection and retrograde filling with Mineral Trioxide Aggregate (MTA) were accomplished and the bony defect was filled with deproteinized bovine bone mineral (DBBM) and covered with biodegradable collagen membrane. Results: After 9-month follow-up, healing of the mandibular right central incisor was uneventful and no swelling, purulence or pain was revealed in the associated area. Probing pocket depth was favorably stable, and the tooth mobility was decreased to the Miller's Class I. Conclusions: Apical cemental tear associated periapical lesion could be successfully treated with removal of the detached cementum in combination with apical surgery and GTR procedure.