• 대한치과교정학회지
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• 제18권2호
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• pp.289-308
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• 1988

The center of resistance is a important determining factor of tooth movement pattern. Laser speckle interferometry, recently developed for noninvasive measurement of small displacements (microns), was used to detect the center of resistance of a maxillary canine which has normal tooth axis and distal curved root in dry human skull. Laser holographic interferometry was used to verify the results of laser speckle interferometry The following result were obtained; 1. In measurement of the degree of rotation, center of resistance was localized when the traction line passed 4.4/18.0 level from alveola crest to root apex. 2. In measurement of the degree of tipping, center of resistance was localized when the traction line passed 4.6/18.0 level from alveola crest to root apex. 3. In holographic determination, the center of resistance was observed when the traction line passed between 3mm to 6mm level from alveola crest to root apex, therefore the results using laser speckle interferometry was coincided with holographic results.

• 대한치과의사협회지
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• 제14권5호
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• pp.457-459
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• 1976

The author experienced a failed ase of root resection which qas performed on the abnormal upper right lateral incisor. The patient was 16year old female. Clinically the effected tooth had neither a carious cavity nor periondontal diseases, ut, a fistula was present on the gum tissue near the root apex. The roentogenogram revealed a pathological area around the apex of the tooth. The results of failed apicoectomy lead to following conclusions. 1. The operated tooth was a case of dense invaginatus which had two pulp cavities and two canals seperated along their entire length. 2. It was the main cause of failure that the second pulp cavity and root canal were not obturated.

• Journal of Periodontal and Implant Science
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• 제53권6호
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• pp.453-466
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• 2023

Purpose: This study aimed to quantify alveolar bone morphology, demonstrate the relationship between tooth angulation and alveolar bone thickness, and introduce a new classification for anterior mandibular teeth related to immediate implant placement (IIP). Methods: Cone-beam computed tomography (CBCT) images of 211 anterior mandibular teeth were analyzed in sagittal slices to measure the thickness of the facial alveolar bone crest (FAB1) and apex (FAB2), and the lingual alveolar bone crest (LAB1) and apex (LAB2). Tooth angulation was classified as 1°-10°, 11°-20°, and >20° according to the tooth's long axis and alveolar bone wall. Spearman correlation coefficients were used to evaluate correlations between the variables. Results: FAB1 and LAB1 were predominantly thin (<1 mm) (84.4% and 73.4%, respectively), with the lateral incisors being thinnest. At the apical level, FAB2 and LAB2 were thick in 99.5% and 99.1% of cases, respectively. Significant differences were documented in FAB2 (P=0.004), LAB1 (P=0.001), and LAB2 (P=0.001) of all mandibular teeth. At all apical levels of the inspected teeth, a significant negative correlation existed between TA and FAB2. Meanwhile, TA showed a significant positive correlation with LAB2 of the lateral incisors and canines. These patterns were then divided into class I (thick facial and lingual alveolar bone), class II (facially inclined teeth) with subtype A (1°-10°) and subtype B (11°-20°), and class III (lingually inclined teeth) with subtype A (1°-10°) and subtype B (11°-20°). Conclusions: Mandibular anterior teeth have predominantly thin facial and lingual crests, making the lingual bone apical thickness crucial for IIP. Although anchorage can be obtained from lingual bone, tooth angulation and tooth types had an impact on IIP planning. Hence, the new classification based on TA and alveolar bone wall may enable rational clinical planning for IIP treatment.

• 치과방사선
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• 제13권1호
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• pp.117-126
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• 1983

The mandibular canal must be considered carefully during surgical treatment, especially surgical extraction of the impacted tooth and intraosseous implant because it contains the important inferior alveolar nerve and vessels. The author investigated the curvatUre of the mandibular canal, the positional frequency of mandibular foramen to the occlusal plane and gonial angle and the positional frequency of the mental foramen to the tooth site using orthopantomograms. The materials consisted of 295 orthopantomograms divided into seven groups ranging from the first decade to 6th. decade. The results were as follows: 1. The position of mandibular foramen was most frequently below occlusal plane in Group Ⅰ (78.6%) and Group Ⅱ (71.2%), above occlusal plane in Group Ⅲ (63.0%), Group IV (71.1%), Group V (57.6%), Group (76.7%) and Group VII (70.0%). 2. The curvature of mandibular canal was 142.8° in Group Ⅰ, 142.09° in Group Ⅱ, 139.34° in Group Ⅲ, 141.48° in Group Ⅳ, 138.45° in Group Ⅴ, 140.77° in Group Ⅵ and 143.89° in Group Ⅶ. 3. The gonial angie was 125.82° in Group Ⅰ, 123.18° in Group Ⅱ, 124.06° in Group Ⅲ, 120.45° in Group Ⅳ, 121.12° in Group Ⅴ, 121.63° in Group Ⅵ and 121.24° in Group Ⅶ. 4. The position of the menta] foramen was most frequently below the apex of mandibular first premolar in Group Ⅰ (57.2%), between the apex of mandibular first and second premolar in Group Ⅱ (59.6%) and Group Ⅲ (48.9%), and below the apex of mandibular second premolar in Group Ⅳ (39.2%), Group Ⅴ (48.5%) Group Ⅵ(46.6%) and Group Ⅶ(56.4%)

• Restorative Dentistry and Endodontics
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• 제44권3호
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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.

• Restorative Dentistry and Endodontics
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• 제42권1호
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• pp.65-71
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• 2017

A revascularization procedure was shown to be the best alternative therapy for immature teeth with necrotic pulp and apical infection. A 12 year old female with a history of trauma to her upper central incisor and a sinus tract was referred for endodontic treatment. She was an active orthodontic patient and had undergone regenerative endodontic treatment for the past 2 years. Clinical examination revealed no response to sensibility, percussion, and palpation tests. The preoperative radiograph showed an open apex and apical rarefaction. The case was diagnosed as previously treated tooth with asymptomatic apical periodontitis. Regenerative endodontic retreatment was performed, and the case was followed for 3 years. Clinical, radiographic, and cone-beam computed tomography follow-up examination revealed an asymptomatic tooth, with evidence of periapical healing and root maturation.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제42권4호
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• pp.231-235
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• 2016

A benign cementoblastoma, which is another name for a true cementoma, is a rare neoplasm that develops from odontogenic ectomesenchyme. It is characterized by a mineralized mass attached to the apex of the root produced by neoplastic cementoblasts. More than 75% of cases arise in the mandible, with 90% of them manifesting in the molar and premolar regions. This neoplasm occurs most commonly in children and young adults, with males being affected slightly more than females. Radiographically, the tumor is observed as a well-defined radiopaque mass that is fused to a tooth root and is surrounded by a radiolucent rim. The treatment of benign cementoblastoma consists of removal of the lesion and extraction of the affected tooth. This report presents an unusual case of benign cementoblastoma in a 31-year-old female, presenting as a densely mineralized mass seen at the apex of the impacted right mandibular canine tooth on radiographs.

• 대한치과보철학회지
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• 제38권4호
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• pp.552-560
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• 2000

Purpose : The purpose of this study was to determine proper position and angulation of an implant for immediate implantation. Materials and Method : From the years 1997 to 2000. 52 Denta $scan^R$ views, 22 upper and 32 lower jaw with an average age of 43 and 40 respectively, were investigated, which comprise intact upper and lower 6 anterior teeth and premolars. On the Denta $scan^R$, the optimal placement for the immediated implantation was simulated. The measuring methods included 1) Angulation difference between tooth long axis and alveolar bone process. 2) Angulation difference of long axis between tooth and installing fixture 3) Distance between center of tooth at cervical area and center of fixture. 4) Distance from root apex to the bone limit of vital structure. One sample t-test was used for statistical analysis. Result : The results were as follows. 1) At the maxillary central incisor and lateral incisor, angulation difference of long axis between tooth and installing fixture was respectively 0.5 and 3.2 degrees with the fixture center's palatally positioned 2mm apart from tooth center. 2) At the lower anterior 6 teeth, that was about $-2.8^{\circ}\;to\;-4.6^{\circ}$ with the fixture center's lingually positioned 1mm apart from tooth center. 3) At the maxillary canine and premolar, that was respectively $11.8^{\circ}\;and \;7.2^{\circ}$ with the fixture center palatally positioned $2\sim2.4mm$ apart from tooth center. 4) At the lower premolar area, that was about $0^{\circ}\;to\;2^{\circ}$ with the fixture center's lingually positioned $0.5{\sim}1mm$ apart from tooth center. 5) Distance from root apex to the bone limit of vital structure, at the maxillary anterior and premolars. was the range of 10 to 12mm, and at the mandibular anterior teeth and the 1st premolar, that was the range of 18 to 20mm. Conclusion : The proper implant position of maxillary anterior and premolar teeth is as paralleled as or more buccally angulated than long axis of tooth with the fixture center's palatally positioned. In mandiblular anterior region, long axis of implants is lingully angulated compared with long axis of tooth and in premolar, almost parelleled with long axis of tooth and alveolar process.

• 한국정밀공학회지
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• 제24권8호통권197호
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• pp.116-121
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• 2007

The length of root canal has to be measured for endodontic treatment. Several electronic apex locators were developed to measure the length of root canal by other researchers. And their accuracies were verified by X-ray or micrometer method. But these methods did not consider the non-linear bends of pulp and had ${\pm}0.5mm$ error which was large enough to measure the length of root canal. The purpose of this study is the introduction of a new method to measure the length of root canal and the verification of the accuracy of an electronic apex locator using a Micro-CT. The length of root canal of 6 teeth were measured with the electronic apex locator. When the electronic apex locator reads 0.5, 0.6, 0.7, 0.8, 0.9 and 1.0 mm length of the file which was inserted in the hole of the tooth to measure the length of root canal. The average (${\pm}$Standard deviation) length of root canal of 6 teeth measured by the Micro-CT was $0.49{\pm}0.03,\;0.59{\pm}0.04,\;0.68{\pm}0.03,\;0.78{\pm}0.03,\;0.90{\pm}0.04\;and\;1.01{\pm}0.03mm$, respectively. The maximum error of the electronic apex locator was 0.06 mm.

• Journal of Periodontal and Implant Science
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• 제37권3호
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• pp.647-653
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• 2007

Rapid crestal bone resorption following maxillary tooth loss is further accentuated in the posterior regions because of pneumatization and enlargement of the maxillary sinuses. A treatment rationale that allows preservation and augmentation of vertical available bone at the time of posterior maxil-lary tooth extraction may offer numerous therapeutic benefits which are more short courses of ther-apy and no needs of additional surgical augmentation. The present study comprised 3 patients who had 4 posterior maxillary teeth with no evident bone between the tooth apex and sinus floor, as estimated through preoperative radiographic analysis. Sinus floor augmentation at the time of tooth extraction was chosen for the ltreatment of these patients. After the tooth was carefully extracted, the empty alveolus was thoroughly debrided and a trephine approach was performed. Particulated autogenous bone was gently pushed beyond the empty alveolus to elevate the sinus membrane using an osteotome. The distance between bone crest and si-nus floor was radiographically estimated 4 months after the first procedure. Another procedure was then carried out to place the implants of 11 mm length without another augmentation procedure. All implant were clinically stable, with no sign of infection. The presented surgical procedure performed at the time of extraction of posterior maxillary teeth in close proximity to the sinus floor allowed placement of implants of proper length.