• Restorative Dentistry and Endodontics
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• v.31 no.5
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• pp.371-377
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• 2006

The purposes of this study were to assess the accuracy of measurements in pre-enlarged canals with small instruments and to compare the accuracies, in enlarged canal, with small size instruments and instruments that match the actual canal diameter using Root ZX, Bingo1020, SmarPex, and e-Magic Finder. Ten extracted teeth were embedded in an alginate model made for testing apex locators. A size 10 file was placed into the root canal until the tip of the file reached the plane of the major diameter of the foramen under a dental operating microscope at the 25 x magnification. The measurement was done with digital caliper and defined as actual length. Electronic length measurement with a size 10 file in pre-enlarged canal was done by reading the index indicating Apex of each device to gain a definite value After completion of canal enlargement to a size 45 file, each difference between actual length and electric measurement value with a size 10 and 40 files in enlarged canal was recorded as L10 and L40. The one-way ANOVA and Scheffe's multiple range tests were computed for analyze the differences among the four apex locators in the same group. The Student's t-test between L10 and L40 of each locator was done. The accuracies of electronic measurements were significantly different among the 4 devices. The file size made no difference on the accuracy of electronic measurement in enlarged canal with same device. The e-Magic Finder was the most accurate device among the 4 apex locators used in this study.

• Journal of the korean academy of Pediatric Dentistry
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• v.45 no.2
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• pp.203-214
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• 2018

Root resorption of the permanent maxillary incisors can occur due to ectopic eruption of the permanent canines. Severe root resorption threatens the long-term survival of the affected incisors. The aim of the present study was to identify risk factors for root resorption of the maxillary incisors associated with impacted maxillary canines. In the present study, we retrospectively analyzed the Cone-Beam Computed Tomography (CBCT) scans of 65 children and adolescents with ectopically erupting maxillary canines (total of 88 impacted canines). Root resorption of central incisors was significantly associated with the mesiodistal position and root development of the adjacent canine. Root resorption of lateral incisors was significantly associated with sex, age, and the buccolingual and vertical position of the adjacent canine. However, enlargement of the dental follicle was not significantly associated with root resorption of adjacent incisors. Although incisor resorption is difficult to diagnose and predict, our findings suggest that changes in the dental follicles of the erupting maxillary canines do not cause resorption of the adjacent permanent incisors. CBCT should be utilized to ensure early diagnosis of impacted canines and precise evaluation of incisor root resorption.

• Journal of the korean academy of Pediatric Dentistry
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• v.48 no.4
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• pp.449-459
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• 2021

This study retrospectively analyzed the effect of clinical factors on the outcomes of REP(regenerative endodontic procedure). Patients who received the REP using triple antibiotic paste due to trauma or fracture of dens evaginatus from February, 2011 to January, 2020 were included in the study. Finally, 57 teeth in 54 patients were selected. Investigated clinical factors were as follows: intentional bleeding, etiology, and root development stage. Treatment outcomes evaluated were as follows: improvement of subjective symptoms, changes in the periapical lesion, and the amounts of root development after REP. To compensate for differences in angulation and position between repeated radiographic examinations, images were aligned by Turboreg plugin. To evaluate the amounts of root development, apical diameter, root area, and root length were measured by ImageJ software. Among the aforementioned factors, intentional bleeding had no significant effect on treatment results. Regarding the etiology, the increase in the root area and the root length was significantly less in trauma cases than in dens evaginatus fracture cases. Considering root development stage, more immature teeth presented more increase in the root area.

• Journal of the korean academy of Pediatric Dentistry
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• v.26 no.2
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• pp.437-445
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• 1999

The purpose of this study was to evaluate the changes of laser doppler flowmeter output associated with stage of root development. Laser Doppler Flowmeter was done in 40 elementary students aged between 7 and 8 years and in 20 adults aged between 23 and 24 years. Among 40 elementary students, 20 had apical foramens with $1{\sim}2mm$ diameters and another 20 had ones with larger diameters than 2mm. The LDF values were analyzed with ANOVA and paired t-test. The results were as follows. 1. Immature root apecies group had a higher tendency than mature root apecies group in LDF values, but there was no statistical significance (p>0.05). 2. There was no statistical significance in LDF values comparing groups with immature root apecies (p>0.05). 3. There were no significant differences between right and left central incisors in LDF values (p>0.05).

• Restorative Dentistry and Endodontics
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• v.25 no.4
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• pp.543-549
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• 2000

Gutta-percha와 근관sealer를 사용한 근관 충전은 가장 많이 이용되고 성공률이 높은 방법이지만, 현재 사용되는 모든 근관sealer는 미세누출을 나타낸다. 따라서 더 효과적인 근관 폐쇄를 이루기 위한 재료 및 방법들이 연구되어왔다. 이중 상아질 접착제는 근관 충전재와 함께 사용되어 미세누출을 감소시키지만, 근관 내에 사용하기에 술식이 복잡하고 기술이 요구된다. 본 연구의 목적은 gutta-percha와 레진계 근관 sealer로 충전한 근관에서 self-etching primer를 미리 도포한 경우와 도포하지 않은 경우의 치근단 미세누출을 비교하고, self-etching primer를 도포함에 있어 근관 내에 적용하는 방법에 따른 미세누출을 비교하는 것이다. 또한 근관sealer와 상아질 계면을 주사전자현미경으로 관찰하여, 이 결과를 미세누출과 관련시켜보고자 하였다. 36개의 발거된 사람의 단근치에서 치관부를 절단, 제거하고 ProFile로 근관 형성한 후, 무작위로 선택하여 4개의 군으로 분류하였다. 1군에서는 주사기와 30게이지 주사 바늘로 self-etching primer를 근관 내에 적용하였고, 2군에서는 self-etching primer를 paper point에 적셔 근관 내에 적용하였다. 3군에서는 self-etching primer를 적용하지 않았다. 1, 2, 3군의 치아를 gutta-percha와 AH26 sealer를 사용하여 continuous wave 충전법으로 충전한 후 치근단공 주위 3mm를 제외한 치근변에 nail polish를 2회 도포하였고, 4군(음성 대조군)은 치근면 전체에 도포하였다. 1군과 2군에서 각각 2개의 치아는 주사전자현미경적 관찰을 위해 준비하였다. 모든 치아를 Methylene Blue 수용액에 48시간동안 침적, 수세한 후 치아 장축에 평행하게 양분하여 10배의 실물확대현미경 하에서 치근단 색소 침투를 관찰하였다. Self-etching primer를 도포한 군과 도포하지 않은 군 사이에는 평균 미세누출량에 유의한 차이가 없었다. 주사 바늘로 적용한 군과 paper point로 적용한 군 사이에도 평균 미세누출량에 유의한 차이가 없었다. 상아질과 근관 sealer계면의 주사전자현미경 관찰 결과 일부분에서 긴밀한 접착 관계를 나타내었고, 다른 부분에서는 간극을 나타내었다.

• Journal of the korean academy of Pediatric Dentistry
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• v.38 no.1
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• pp.44-50
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• 2011

An immature tooth with infected pulp has numerous potential complications. Conventional apexification with calcium hydroxide has several disadvantages, including susceptibility to tooth fracture. This method does not promote continual root development. Pulp revascularization of a necrotic, immature permanent tooth will allow further development of the root and dentinal structure. Disinfection of the root canal system is a prerequisite for pulp revascularization and tissue regeneration. A combination of antibiotic drugs (ciprofloxacin, metronidazole, and minocycline) is effective for disinfection of necrotic pulp, and has been used successfully in regenerative endodontic treatment. These case reports involve the treatment of 3 immature permanent teeth with necrotic pulp using a 3-Mix paste and mineral trioxide aggregate. All cases showed the notable apical maturation with closure of the apex and increased thickness of dentinal walls. This approach suggests a paradigm shift in treating endodontically involved immature permanent teeth from the traditional apexification with calcium hydroxide to the conservative approach by providing a favorable environment for tissue regeneration.

• Restorative Dentistry and Endodontics
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• v.29 no.5
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• pp.439-445
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• 2004

The purpose of this study was to evaluate the influence of plugger penetration depth on the apical extrusion of root canal sealer during root canal obturation with Continuous Wave of Condensation Technique. Root canals of forty extracted human teeth were divided into four groups and were prepared up to size 40 of 0.06 taper with ProFile. After drying. canals of three groups were filled with Continuous Wave of Condensation Technique with System $B^{TM}$ and different plugger penetration depths of 3. 5, and 7 mm from the apex. Canals of one group were filled with cold lateral compaction technique as a control. Canals were filled with non-standardized master gutta-percha cones and 0.02 mL of Sealapex. Apical extruded sealer was collected in a container and weighed. Data was analyzed with one-way ANOVA and Duncan's Multiple Range Test. 3 and 5 mm penetration depth groups in Continuous Wave of Condensation Technique showed significantly more extrusion of root canal sealer than 7 mm penetration depth group (p < 0.05). However, there was no significant difference between 7 mm depth group in Continuous Wave of Condensation Technique and cold lateral compaction group (p < 0.05). The result of this study demonstrates that deeper plugger penetration depth causes more extrusion of root canal sealer in root canal obturation by Continuous Wave of Condensation Technique. Therefore, special caution is needed when plugger penetration is deeper in the canal in Continuous Wave of Condensation Technique to minimize the amount of sealer extrusion beyond apex.

• The Journal of the Korean dental association
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• v.10 no.3
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• pp.149-153
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• 1972

The apical foramen is not always found on the very tip of the root. The apical foramen may make its exit on the mesial, distal, labial or lingual side of a root slightly short of the root apex rather than at the root apex itself. The author collected 43 upper first molars and 84 lower first molars as a samples. Apical foramens were carefully checked and examined these location on each tip. (table 1) 1. About 33% to 49% of upper cases were found on extreme tip of roots and the remaining cases were on the distal side or mesial side. 2. Except distal simple canal of lower molars, approximately 40% to 50% were located on the very tip of the root. The remaining cases were on distal or mesial surface. 3. On lower distal simple canal, about 51% of cases made its exit on distal side. The remaining cases located on the tip end or mesial side.

• Journal of the korean academy of Pediatric Dentistry
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• v.26 no.2
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• pp.317-322
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• 1999

Dens invaginatus is a developmental anomaly resulting from an invagination of the enamel organ. The incidence is highest with maxillary permanent lateral incisors. The reported occurrence ranges from 0.04 to 10%. This anomaly may involve the pulp and periapical tissues and cause pulpal inflammation, loss of vitality, apical and lateral periodontitis, periapical abscesses and cysts and stimulate internal resorption. Oehlers describes dens invaginatus as occurrence in three forms. In treating type 3 invaginatus, treatment strategy can be determined by considering the complexity and accessibility of invagination. In this case, showing simple invagination, it could be treated by simple endodontic treament confining to invagination without loss of vitality of tooth. After treatment of the present case, the results were as follows: 1. In type 3 dens invagiantus, if the tooth is vital and there is no evidence of communicating between invagination and pulp, we can save the vitality of the tooth and resolve the lesion by endodontic treament confining to the invagination. 2. In the invagination with opened apex, the closure of apex can be induced by apexification procedure doing this, we can avoid the neccessity of surgical intervention.

• Journal of the korean academy of Pediatric Dentistry
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• v.32 no.1
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• pp.18-25
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• 2005

Traumatic bone cyst is a nonodontogenic cyst without epithelial-linig which contains fluid in it's cavity, and it is limited by bone walls with no evidence of infection. Traumatic bone cyst is asymptomatic and appears more frequently in the second decade. Gender distribution is approximately equal, although males are affected slightly often than females. Radiographically the lesion shows a well demarcated radiolucent lesion of variable size and the lesion may have scalloped margins. The adjacent teeth to traumatic bone cyst remains vital. Traumatic bone cyst is usually treated by surgical exploration and currettage of the lesion. In the first case of this case report, the patient was refered from the local dental clinic for the radiolucent area under the left mandibular first molar. From the panorama radiograph at the first visit, the radiolucent area of the left mandible showed a well defined scalloped margin and identified as traumatic bone cyst. In the second case, the patient have visited for the chief complaint of swelling and abcess of right maxillary second premolar. In the radiographic check up with panorama radiograph, the radiolucent lesion with well demarcated scalloped margin was found in the right mandible body, and identified as traumatic bone cyst. In the first case, overinstrumentation was done through the mesial root canal to irrigate the lesion. In the second case, not any treatment was done, and watched the progression of the lesion. And in both cases, after two month, the radiolucency and the size of the lesion has decreased to show healing in progress.