• Annals of Clinical Neurophysiology
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• 제8권1호
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• pp.1-5
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• 2006

The head thrust maneuver is a simple bedside test of the higher frequency vestibulo-ocular reflex, which is based on Ewald's second law. It is performed by grasping the patient's head and applying a brief, small-amplitude, high-acceleration head turn, first to one side and then to the other. The patient fixates on the examiner's nose and the examiner watches for corrective rapid eye movements (saccades), which are a sign of decreased vestibular response. The "catch-up" saccades after a head thrust in one direction indicate a peripheral vestibular lesion on that side (in the labyrinth or the $8^{th}$ nerve including the root's entry zone in the brain stem). An individual pair of vertical semicircular canals can also be stimulated by turning the head to the right or left by $45^{\circ}$ and then by rotating the head in the pitch plane relative to the body. Recent studies have suggested that assessment of individual semicircular canal function by head thrust test may provide useful information for anatomical and functional details of a variety of peripheral vestibulopathies and for predicting the prognosis of vestibular neuritis. In central vestibulopathy, the head thrust test may also be valuable sign to determine dysfunction of the central pathways from individual semicircular canals and its role for the development of diverse central nystagmus.

• Restorative Dentistry and Endodontics
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• 제28권1호
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• pp.50-56
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• 2003

The purpose of this study was to evaluate the effects of EDTA and pulsed Nd :YAG laser on apical leak-age of canal obturation. Forty-eight single-rooted teeth were used in this study. The teeth were instrumented up to a size 40 K-file and irrigated with 2.5% NaOCl between each fie size. And the teeth were divided into 4 groups. In group A, the root canals were irrigated with a final flush of 5ml 2.5% NaOCl as a control group. The teeth in group B were irrigated with a final flush of 5ml 17% EDTA. The teeth in group C and D were irradiated by pulsed Nd：YAG laser(laser parameters were set at 1W, 100mJ, 10Hz, and 2W, 100mJ, 20Hz respectively). The results were as follows : 1. Apical leakage was observed in 50% of samples in group A, 30% of samples in group B, 20% of samples in group C, and 10% of samples in group D. 2. The teeth in group B had less leakage than group A, but there was no statistically significant differences(p＞0.05). 3. The teeth in group C, D had less leakage than group A, and there was statistically significant differences(p＜0.05). 4. The teeth in group C, D had less leakage than group B, but there was no statistically significant differences(p＞0.05). 5. There was no significant differences in apical leakage between group C and group D(p＞0.05).

• Restorative Dentistry and Endodontics
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• 제1권1호
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• pp.26-32
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• 1975

After a vital pulpotomy in dogs' teeth, the responses of the remaining pulp tissue under hydroxides (calcium hydroxide, magnesium hydroxide, aluminium hydroxide and zinc hydroxide) were studied histologically. The class V cavities were prepared on the teeth and the pulp was amputated. Each hydroxide was placed over the amputated tissue and the cavity was sealed with zinc oxide eugenol cement. Animals were sacrificed after 3 days, 1, 2, and 3 weeks following the operation. The teeth were decalcified, sectioned and stained with hematoxylin and eosin. Microscopic examination reveals as follows; 1. Calcium hydroxide: Inflammatory change was seen in the superficial portion of the remaining pulp tissue at the 3rd day and 1st week. The incompleted calicified material began to be deposited from the canal wall at the 2nd week, and the advanced calcified material was seen at the 3rd week. 2. Magnesium hydroxide: Severe inflammatory change was seen in the superficial portion of the remaining pulp from the 3rd day and the 1st week samples. Inflammatory change was decreased at the 2nd week and the slight calcified material was deposited from the root canal at the 3rd week. 3. Aluminium hydroxide: Severe inflammatory changes were seen in the remaining pulp tissue, the blood vessel was dilated, and the odontoblasts were destroyed at the 3rd day and 1st week. The fibrous degeneration spread to the apex at the 2nd week. There was no evidence of newly formed odontoblasts or deposition of calcified material underneath aluminium hydroxide. 4. Zinc hydroxide: The micrscopic picture was destructive. A thick necrotic layer was found under the amputated surface at the 3rd day and 1st week. Granulation tissue formation as well as chronic inflammatory changes extended to the apical area in the pulp tissue. Also there were no sign of odontoblastic formation or calcified material at the 2nd and 3rd week.

• Journal of Korean Dental Science
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• 제3권2호
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• pp.12-19
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• 2010

Despite the latest advancement made in its techniques and devices/apparatuses and the resulting rising expectation in the field of dental surgery, apicoectomy performed in the molar teeth remains a technical challenge and lacks evidence substantiated by long-term follow-up studies. This study sought to investigate the treatment outcomes and post-operative success rate in the root-end resected molar teeth accompanied by a high level of surgical risks due to their close proximity to the mandibular canal and maxillary sinus. A total of 68 patients who received treatment at Livingwell Dental Hospital between 2004 and 2010 and underwent apical surgery in the maxillary or mandibular molar area were enrolled in this study. A total of 160 roots collected from 75 molar teeth were subjected to surgical endodontic treatment and subsequently evaluated clinically as well as radiographically. Based on the results of the study, the clinical success rate was found to be 78.8% in cases involving radiological healing. Likewise, 90.7% of the roots recorded a robust clinical survival rate, but with incomplete healing as shown by radiography. The results indicate that the apical procedure involving molar teeth is a prognosis-friendly method that promises positive outcomes and higher success rate based on long-term follow-up observations.

• 대한소아치과학회지
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• 제42권2호
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• pp.197-202
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• 2015

치수괴사가 있는 미성숙 치아를 치료할 때 많은 도전을 받는데, 역사적으로 수산화칼슘을 장기간 적용하여 석회 차단벽의 형성을 유도하는 것이 사용되어 왔다. 2004년 개방성 근첨을 치료할 수 있는 '재혈관화'라는 새로운 방법이 소개되어 널리 인정받게 되었다. 기존의 근첨형성술과 이 방법이 다른 점은 근관을 세 항생제 (ciprofloxacin, metronidazole and minocycline)로 소독하고 인위적으로 근관내 출혈을 유도한 다음, MTA로 밀폐한다. 괴사된 미성숙 영구치를 재생 근관치료를 성공적으로 하였을 경우, 지속적인 치근의 성장과 상아질벽 두께의 증가, 및 치근첨의 폐쇄를 얻을 수 있다. 이는 치수-상아질 복합체의 기능적 회복과 발달이 궁극적으로 자연치의 유지에 기여하는 점이다.

• Restorative Dentistry and Endodontics
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• 제19권1호
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• pp.205-216
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• 1994

The purpose of this study is to evaluate of apical plug materials for the contral of extrusion and sealing ability of high-temperature thermoplasticized gutta-percha in plastic root canal blocks. Seventy seven plastic blocks with canal preformed were instrumented with # 50K file 1 mm beyond apical foramen. Blocks were randomly divided into 5 groups of 15 blocks each. Group 1 was filled by high-temperature thermoplasticized gutta-percha only. The another 4 groups were placed with apical plug materials each other and then remaining space was back filled with high temperature thermoplasticized gutta-percha Apical plug materials were used as follows; Group 2: Thermoplasticized gutta-percha (Thermoplasticized gutta-percha group) Group 3 :. Calcium hydroxide powder (Calcium hydroxide group) Group 4 : Silver point (Silver point group) Group 5 : Gutta-percha cone softened by chloroform (Gutta-percha cone group) All the blocks were stored in 100 % relative humidor at room temperature for 14 days. Filling material extruded was removed carefully and then weighed in analytic balance. Each block was placed in centrifuge tube filled with India ink, and then centrifuged for 20 minutes at 3,000 rpm. Apical leakage was measured from the apical foramen to the most coronal level of dye leakage in millimeter by two examiners under a stereoscope. The data were analysed statistically by Student's t-test The obtained results were as follows; 1. The amounts of material extruded through the foramen decreased in all of groups used apical plug materials (P<0.01). 2. Silver point group and gutta-percha cone group were similar linear leakage to high-temperature thermoplasticised gutta-percha technique only (P>0..5). 3. Calcium hydroxide group and thermoplasticized gutta-percha group showed more liner leakage than high-temperature thermoplasticized gutta-percha only (P<0.01, P<0.05). 4. High-temperature thermoplasticized gutta-percha technique with silver point and gutta-percha cone as apical plugs showed less linear leakage and less extrusion of filling material.

• Restorative Dentistry and Endodontics
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• 제48권1호
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• pp.10.1-10.9
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• 2023

Objectives: This study compared the buckling resistance of 3 nickel-titanium (NiTi) retreatment file systems and the torque/force generated during retreatment. Materials and Methods: The buckling resistance was compared among the D-RaCe (DR2), HyFlex Remover, and Mtwo R25/05 retreatment systems. J-shaped canals within resin blocks were prepared with ProTaper NEXT X3 and obturated by the single-cone technique with AH Plus. After 4 weeks, 4 mm of gutta-percha in the coronal aspect was removed with Gates-Glidden drills. Retreatment was then performed using DR1 (size 30, 10% taper) followed by DR2 (size 25, 4% taper), HyFlex Remover (size 30, 7% taper), or Mtrwo R25/05 (size 25, 5% taper) (15 specimens in each group). Further apical preparation was performed with WaveOne Gold Primary. The clockwise torque and upward force generated during retreatment were recorded. After retreatment, resin blocks were examined using stereomicroscopy, and the percentage of residual filling material in the canal area was calculated. Data were analyzed using 1-way analysis of variance with the Tukey test. Results: The HyFlex Remover files exhibited the greatest buckling resistance (p < 0.05), followed by the Mtwo R25/05. The HyFlex Remover and Mtwo R25/05 files generated the highest maximum clockwise torque and upward force, respectively (p < 0.05). The DR1 and DR2 files generated the least upward force and torque (p < 0.05). The percentage of residual filling material after retreatment was not significantly different between file systems (p > 0.05). Conclusions: NiTi retreatment instruments with higher buckling resistance generated greater clockwise torque and upward force.

• Restorative Dentistry and Endodontics
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• 제48권3호
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• pp.28.1-28.13
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• 2023

Objectives: This study aimed to investigate the effect of the application method of 2% chlorhexidine (CHX) and its influence on the adhesion of fiberglass posts cemented with a self-adhesive resin cement. Materials and Methods: Sixty human mandibular premolars were endodontically treated and divided into 5 groups (n = 12), according to the canal irrigant and its application method: 2 groups with conventional syringe irrigation (CSI)-2.5% sodium hypochlorite (NaOCl) (control) and 2% CHX- and 3 groups with 2% CHX irrigation/activation-by passive ultrasonic irrigation (PUI), Easy Clean file, and XP-Endo Finisher file. Two roots per group were evaluated for smear layer (SL) removal by scanning electron microscopy. For other roots, fiber posts were luted using a self-adhesive resin cement. The roots were sectioned into 6 slices for push-out bond strength (BS) (7/group) and nanoleakage (NL) (3/group). Data from SL removal were submitted to Kruskal-Wallis and Student-Newman-Keuls tests (α = 0.05). Data from BS and NL were evaluated by 2-way analysis of variance and Tukey's test (α = 0.05). Results: For SL removal and BS, the CHX irrigation/activation promoted better values than CSI with CHX (p < 0.05), but it was not significantly different from CSI with NaOCl (p > 0.05). For NL, the lowest values were obtained by the chlorhexidine irrigation/activation groups (p < 0.05). Conclusions: Active 2% CHX irrigation can be used to improve the post space cleaning and adhesion before fiber post cementation with self-adhesive resin cements.

• Restorative Dentistry and Endodontics
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• 제33권1호
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• pp.66-75
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• 2008

본 연구에서는 근관형성의 치근단 크기가 근관 충전의 치근단 폐쇄에 미치는 영향에 대해 알아보고자 하였다. 36개의 단근관, 단근치를 대상으로 3가지 치근단 크기 (Master apical file : #25, #40, #60)에 따라 3가지 실험군으로 나누어 $Profile^{(R)}$과 $LightSpeed^{(R)}$를 이용하여 근관을 확대하고, Modified continuous wave technique으로 근관충전을 시행하였다. 미세누출의 측정을 위해 실험군당 10개의 치아를 1주일간 India ink에 넣어 색소 침투를 일으키고 치아를 투명화시켜 미세누출의 정도를 측정하였다. 미세누출에 치근단 크기가 미치는 영향을 분석하기 위하여 Kruskal-Wallis one-way ANOVA를 시행하였고, 사후 검정을 위하여 Student-Newman-Keuls method를 시행하였다. 또한, 치아 단면의 형태를 관찰하기 위하여 색소 침투까지 실행된 각 실험군당 2개의 치아를 근첨 1 mm에서 4 mm까지 1 mm간격으로 수평 절단하고 사진 촬영하였다. 각 실험군에서 측정된 미세누출양을 Krustal-Wallis one-way ANOVA에서 분석한 결과 치근단 크기는 유의성 있게 (P < 0.05) 미세누출에 영향을 미쳤으며 치근단 크기가 클수록 미세누출의 평균간과 표준편차 값은 감소하는 경향을 보였다. Student-Newman-Keuls method를 통한 사후 검정에서 치근단 크기가 #25 - #40, #25 - #60에서 유의 한 차이를 보였으며 #40 - #60간에는 통계적인 유의차는 없었다. 단면형태에서는 대부분의 치아에서 난원형의 근관 형태를 관찰 할 수 있었고, 치근단의 크기가 작을수록 성형된 근관에 불규칙한 내면이 존재하였고 gutta-percha나 sealer로 충전되지 않는 recess의 면적이 증가함을 알 수 있었으며 이러한 recess는 미세누출의 통로가 됨을 확인 할 수 있었다. 본 연구 결과, Modified continuous wave technique으로 근관충전시 근관 형성된 치근단 크기가 커질수록 보다 일관되고 성공적 인 결과를 예상할 수 있는 근관충전을 시행할 수 있음을 알 수 있었다.

• Restorative Dentistry and Endodontics
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• 제35권2호
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• pp.80-87
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• 2010

이 실험의 목적은 NaOCl과 CHX의 혼합사용 시, 발생하는 침전물의 형성을 막기 위해 두 용액간의 접촉을 줄일 수 있는 여러 가지 방법을 비교하고, 관찰된 침전물의 원소를 분석하는 것이다. 발거된 50개의 단근치를 사용하였으며 2.5% NaOCl을 이용하여 .04 taper ProFile #40까지 근관형성 하였다. 치아는 다음과 같은 근관세척 방법에 따라 4개의 실험군과 1개의 대조군으로 나누었다; 대조군: 2.5% NaOCl, 1군: 2.5% NaOCl + 2% CHX, 2군: 2.5% NaOCl + paper points + 2% CHX, 3군: 2.5% NaOCl + .04/#45 근관확대 + 2% CHX, 4군: 2.5% NaOCl +95% alcohol+ 2% CHX. 근관세척 후 치아를 양분하고 치관부, 중간부, 치근부 세부위로 나누어 전계 방사형 주사 전자현미경을 통하여 잔사 비율, 개방 상아세관 비율, 상아세관 내 물질의 원소분석을 시행하였다. 실험결과, 실험군 사이에 잔사비율과 개방된 상아세관 비율 비교에서 통계학 적으로 유의할 만한 차이는 나타나지 않았다. 1 군의 한 시편에서 C의 함유량이 높게 나타났으며 N과 Cl도 함께 검출되어 para-chloraniline으로 추정되며, 1 군의 다른 시편과 나머지 실험군에서는 O, P, C, Ca의 순으로 함유량이 높은 것으로 나타나 수산화인회석으로 추정된다. NaOCl 세척 후 바로 CHX 세척을 한 군에서 PCA로 의심되는 물질이 검출된 바, 두 용액의 직접적인 접촉을 피하기 위해 주의가 필요하며, 본 실험에 사용된 여러 근관 세척방법 이용 시 침전물의 형성을 예방할 수 있을 것이다.