• 대한의용생체공학회:학술대회논문집
• /
• 대한의용생체공학회 1997년도 춘계학술대회
• /
• pp.316-317
• /
• 1997

For successful endodontic therapy, complete and accurate biochemical and chemical preparations will allow accurate root canal. Hence the accurate determination of root length is very important for the highest rates of success in endodontic therapy. Among the apex locators, frequency dependent type has higher accuracy and more advantages than others. In this paper, we proposed better frequencies for the method of measuring root canal length by the ratio of two different impedances. It was found that 500Hz and 10kHz is better selection than other frequencies used in the commercial products.

• 치과방사선
• /
• 제13권1호
• /
• pp.87-96
• /
• 1983

Radiographic measurements on the width of mandibular cortical plate and the lamina dura and on the root length were done in 42 patients who were in long-term Dilantin medication. Osteoporosis and root abnormalities were also investigated. The obtained results were as follows: 1. The number of male patients was greater than that of female patients. 2. The width of mandibular cortical plate was thinner in patient group than in control group. 3. There was no significant change in the width of lamina dura between the patient group and control group. 4. The root length of patient group was generally shorter than that of control group. 5. There were evidences of generalized mandibular osteoporosis and alteration in mandibular canal wall in 8 patients. (19%) 6. In Dilantin induced osteomalacia, the radiographic changes of mandibular canal wall and mandibular cortical plate were prominent, but that of lamina dura was not significant.

• Restorative Dentistry and Endodontics
• /
• 제33권6호
• /
• pp.518-525
• /
• 2008

본 연구의 목적은 제 IV형 근관에서 Continuous Wave 가압법을 이용하여 충전할 때 System B Plugger tip의 깊이에 따른 근단부 밀폐효과를 평가하기 위함이다. 50개의 J형 만곡을 갖는 레진 블록에 부러진 F3 ProTaper 파일을 이용해 근관장에서 3mm 지점에 ledge를 형성한 후, F1 ProTaper Ni-Ti file을 이용해 레진 블록을 천공시켜 제 IV형 근관을 형성하고 System B Plugger tip의 깊이에 따라 3개의 실험군과 1개의 대조군으로 분류하였다. 제 IV형 근관의 거터퍼쳐와 실러의 길이는 확대경하에서 캘리퍼를 이용해 측정하였고 다음과 같은 결과를 얻었다. 1. 대조군의 설측 근관에서 거터퍼쳐와 실러 모두 관찰되지 않았다. 2. 3 mm군에서는 5 mm 또는 7 mm군에 비해 유의하게 많은 거터퍼쳐의 충전이 관찰되었다 (p<0.05). 3. 7 mm군에서는 유의하게 많은 빈 공간이 관찰되었다 (p<0.05).

• 치과방사선
• /
• 제28권2호
• /
• pp.435-459
• /
• 1998

In order to achieve a successful endodontic treatment, root canals must be obturated three-dimensionally without causing any damage to apical tissues. Accurate length determination of the root canal is critical in this case. For this reason, I've used the conventional periapical radiography, Digora/sup (R)/(digital imaging system) and Root ZX/sup (R)/(the frequency dependent type apex locator) to measure the length of the canal and compare it with the true length obtained by cutting the tooth in half and measuring the length between the occlusal surface and the apical foramen. From the information obtained by these measurements, I was able to evaluate the accuracy and clinical usefulness of each systems. whether the thickness of files used in endodontic therapy has any effect on the measuring systems was also evaluated in an effort to simplify the treatment planning phase of endodontic treatment. 29 canals of 29 sound premolars were measured with #15, #20, #25 files by 3 different dentists each using the periapical radiography. Digora/sup (R)/ and Root ZX/sup (R)/. The measurements were then compared with the true length. The results were as follows: 1. In comparing mean discrepancies between measurements obtained by using periapical radiography(mean error: -0.449±0.444 mm), Digora/sup (R)/(mean error: -0.417±0.415 mm) and Root ZX/sup (R)/(mean error: 0.123±0.458 mm) with true length. periapical radiography and Digora/sup (R)/ system had statistically significant differences(p<0.05) in most cases while Root ZX/sup (R)/ showed none(p>0.05). 2. By subtracting values obtained by using periapical radiography, Digora/sup (R)/ and Root ZX/sup (R)/ from the true length and making a distribution table of their absolute values. the following analysis was possible. In the case of periapical film. 140 out of 261<53.6％) were clinically acceptable satisfying the margin of error of less than 0.5 mm. 151 out of 261 (53,6％) were acceptable in the Digora/sup (R)/ system while Root ZX/sup (R)/ had 197 out of 261(75.5％) within the limits of 0.5mm margin of error. 3. In determining whether the thickness of files has any effect on measuring methoths, no statistically significant differences were found(p>0.05). 4. In comparing data obtained from these methods in order to evaluate the difference among measuring methods, there was no statistically significant difference between periapical radiography and Digora/sup (R)/ system(p>0.05), but there was statistically significant difference between Root ZX/sup (R)/ and periapical radiography(p<0.05). Also there was statistically significant difference between Root ZX/sup (R)/ and Digora/sup (R)/ system(p<0.05). In conclusion, Root ZX/sup (R)/ was more accurate when compared with the Digora/sup (R)/ system and periapical radiography and seems to be more effective clinically in determining root canal length. But Root ZX/sup (R)/ has its limits in determining root morphology and number of roots and its accuracy becomes questionable when apical foramen is open due to unknown reasons. Therefore the combined use of Root ZX/sup (R)/ and the periapical radiography are mandatory. Digora/sup (R)/ system seems to be more effective when periapical radiographs are needed in a short period of time because of its short processing time and less exposure.

• Journal of Periodontal and Implant Science
• /
• 제26권4호
• /
• pp.933-948
• /
• 1996

The purpose of this study was to examine the anatomic structures of the mandible-inferior alveolar canal, mental foramen, mental canal-with panoramic radiography and conventional tomography and to compare both radiographic techniques in conjunction with endosseous implants. In this study 14 adult dentulous mandibles -27 cases of right and left side of mandibles- were examined and the results were as follows. 1. The distance between superior border of the inferior alveolar canal and the alveolar ridge crest showed a decreasing tendency from the mental foramen to 4cm posterior to the mental foramen. 2. The mean diameter of the inferior alveolar canal was $4.11{\pm}0.50mm$ with panoramic radiography and $3.29{\pm}0.59mm$ with conventional tomography. 3. The inferior border of the inferior alveolar canal and inferior border of the mandible was closest at 2cm posterior to the mental foramen but it was not statistically significant. the mean distance was $1l.64{\pm}2.95mm$ in panoramic radiography and $1l.68{\pm} 2.91mm$ in conventional tomography. 4. The inferior alveolar canal located lingually in bucco-lingual direction 16%(mental foramen), 54%(lcm posterior to the mental foramen), 68%(2cm posterior to the mental foramen), 50%(3cm posterior to mental foramen), 55%(4cm posterior to the mental foramen). 5. Mean length of the anterior loop of the mental canal was 2.73mm, and the loop below 2mm was 35% and 15% of mental canal was invisible in panoramic radiography. 6. The minimum interforaminal distance was 56.7mm, the maximum distance was 73.2mm and the mean distance was 66.42mm in panoramic radiography. 7. The mean distance between midpoint of the mental canal and alveolar ridge crest was 16.24mm and the mean buccolingual angulation of the mental canal was $52.98^{\circ}$ in conventional tomography. 8. In comparison of panoramic radiography and conventional tomography, inferior alveolar canal is better visualized with conventional tomography than panoramic radiography from the mental foramen to the 2cm posterior to the mental foramen, while visiblity of conventional tomography prominently decreased in 4cm posterior to the mental foramen and alveolar ridge crest is better visualized with panoramic radiography than conventional radiography at the mental foramen and at 4cm posterior to the mental foramen. In radiologic examination of anatomic structures of the mandible for endosseous implants, panoramic radiography and conventional tomography can be effectively used when it is used to overcome the anatomic limitations.

• Restorative Dentistry and Endodontics
• /
• 제38권1호
• /
• pp.26-30
• /
• 2013

Objectives: The aim of this study was to investigate the relationship between the apical foramen morphology and the length of merged canal at the apex in type II root canal system. Materials and Methods: This study included intact extracted maxillary and mandibular human premolars (n = 20) with fully formed roots without any visible signs of external resorption. The root segments were obtained by removing the crown 1 mm beneath the cementum-enamel junction (CEJ) using a rotary diamond disk. The distance between the file tip and merged point of joining two canals was defined as Lj. The roots were carefully sectioned at 1 mm from the apex by a slow-speed water-cooled diamond saw. All cross sections were examined under the microscope at ${\times}50$ magnification and photographed to estimate the shape of the apical foramen. The longest and the shortest diameter of apical foramen was measured using ImageJ program (1.44p, National Institutes of Health). Correlation coefficient was calculated to identify the link between Lj and the apical foramen shape by Pearson's correlation. Results: The average value of Lj was 3.74 mm. The average of proportion (P), estimated by dividing the longest diameter into the shortest diameter of the apical foramen, was 3.64. This study showed a significant negative correlation between P and Lj (p < 0.05). Conclusions: As Lj gets longer, the apical foramen becomes more ovally shaped. Likewise, as it gets shorter, the apical foramen becomes more flat shaped.

• Restorative Dentistry and Endodontics
• /
• 제40권4호
• /
• pp.334-335
• /
• 2015

• 대한장애인치과학회지
• /
• 제3권2호
• /
• pp.97-100
• /
• 2007

In patients with cerebral palsy, dental treatments, which require absolute patient's corporation, have many difficulties because of muscle spacity, involuntary muscle movements and spasm. Especially in endodontic treatments which very meticulous instrumentation is needed, these muscle discordances may lead to unexpected accidents such as tissue damage while filing, over-instrumentation and swallowing instruments. Also, taking radiographs for measuring canal length is often hindered by walking and movement disorders. This paper is to present a clinical case of one-visit root canal treatment using electrical apex locator under general anesthesia in a cerebral palsy patient.

• 대한치과보존학회:학술대회논문집
• /
• 대한치과보존학회 2003년도 제120회 추계학술대회 제 5차 한ㆍ일 치과보존학회 공동학술대회
• /
• pp.592-593
• /
• 2003

I. Objectives The purpose of this study was to compare in vivo the biocompatibility of new calcium phosphate-based root canal sealers(CAPSEAL I, CAPSEAL II) with another type of commercially available calcium phosphate sealer (Apatite Root Sealer type I, Apatite Root Sealer type II) and zinc oxide-eugenol-based sealer (Pulp Canal Sealer EWT) after implantaion in rat subcutaneous tissue. II. Materials and Methods 64 Sprague-Dawley rats were used. There were five groups of three animals each for experimental period of 1, 2, 4, and 12 weeks. The teflon tubes, 5mm in length with an inner diameter of 1.5mm, were washed with ethanol and distilled weter and autoclaved.(omitted)

• Journal of Oral Medicine and Pain
• /
• 제39권4호
• /
• pp.133-139
• /
• 2014

Purpose: There have been reports regarding the various factors associated with the level of discomfort and recovery from neurosensory symptoms in patients with trigeminal nerve injury. However, the contributing factors remain uncertain and poorly understood. The purpose of this paper was to investigate the possible association between various factors expected to affect neurosensory discomfort and recovery in patients with mandibular nerve injury after dental implant surgery. Methods: Eighty-nine post-dental implant surgery patients with mandibular nerve injury were enrolled in this retrospective analysis. A medical records review of the patients was done to determine if the patients' improvement was related to pain intensity, the length of time between the injury and removal of the implant or the depth of penetration of the implant into the mandibular canal as determined by cone-beam computed tomography. Results: There was no significant linear relationship between pain intensity and symptomatic improvement (p=0.319). There was no significant linear relationship between the level of mandibular canal penetration and either pain intensity (p=0.588) or symptomatic improvement (p=0.760). There was a statistically significant linear relationship between length of time before the injury was treated, both with pain intensity (p=0.004), and symptomatic improvement (p=0.024). Conclusions: Our findings indicate that the length of time between nerve injury and initiation of conservative treatment is more closely related to the pain intensity and symptomatic improvement than other factors, including the level of mandibular canal invasion. Additionally, increased pain intensity and decreased symptomatic improvement can be expected over time, because of this linear trend. Therefore, although direct injury to the nerve is the most important factor contributing to a neurosensory disturbances, early neurosensory assessment and initiation of conservative treatment should be done to optimize recovery.