• Journal of Ecology and Environment
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• 제48권1호
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• pp.110-119
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• 2024

Background: The Mae Kha Canal is one of Chiang Mai's most important waterways. It supports local agriculture, irrigation, and transportation as well as provides stormwater drainage to prevent floods. Due to the unregulated rapid urbanization of the city and lack of efficient waste and wastewater management systems over the past few decades, the canal has become heavily polluted. This study aimed to evaluate the water quality of Mae Kha canal through assessment of the physico-chemical water quality and coliform bacteria. Moreover, benthic macroinvertebrates were samples and assessed using the Biological Monitoring Working Party (BMWP^Thai) and Average Score Per Taxon (ASPT^Thai) as biological indices. Results: The physico-chemical showed low dissolved oxygen levels, high levels of ammonia and phosphates, and elevated levels of biochemical oxygen demand, indicating that the water quality had significantly deteriorated. The canal was found to be heavily polluted, with most sites falling into the polluted to very heavily polluted. Coliform bacteria analysis revealed alarmingly high levels of total coliform bacteria and fecal coliform bacteria in the canal. The BMWP^Thai and ASPT^Thai scores indicated poor to very poor water quality. Conclusions: The physico-chemical and coliform bacteria indicated that the water quality of the Mae Kha canal had significantly deteriorated. The biological indices also indicated the poor to very poor water quality. This study underscores the urgent need for comprehensive remediation efforts, emphasizing strategic planning, investment, and community engagement to revive the canal's ecological health and water quality.

• 한국임상수의학회지
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• 제21권2호
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• pp.149-153
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• 2004

This study was to determine the procedure for ultrasonographic imaging of the canine external ear canal(ECC). By infusion of warm saline solution into the ear canal, a real-time B mode ultrasonographic examination of the ECC was performed in five healthy Beagle dogs and two dogs with severe otitis externa. The ultrasonography was very useful to detect the structures of the ECC and the tympanic membrane. An 11 NHz linear probe was permitted to assess an anechoic lumen of the ECC and a hyperechoic cartilage surrounding the ear canal. In two dogs with otitis externa, it could be assessed the ECC with ultrasonography without ear cleansing. A lumen of the ECC was irregular and a cerumen could be seen, but edematous inflammatory changes of the ECC could not be identified. The results suggest that ultrasonography of the ECC with an 11 NHz linear probe after infusing the saline solution into the ear canal may be an accurate, non-invasive, rapid, and widely available method for assessment of the ear canal diseases such as otitis externa, polyp, stenosis, hyperplasia, and foreign body in dogs.

• Restorative Dentistry and Endodontics
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• 제13권1호
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• pp.79-89
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• 1988

The purpose of this study was to evaluate the canal preparation time, deviation of the apex (Zipping), and debridement effect of the canal of three canal preparation techniques. Thirty extracted 1st and 2nd molars were divided into 3 groups and each group was enlarged by ultrasonic, sonic or hand instrument. The specimens were examined under scanning electron microscope and light microscope. The results were as follows: 1. In the canal preparation time, ultrasonic group was the shortest, followed by sonic, hand group. All pairs of groups were significantly different at the 0.05 level. (P < 0.05) 2. In the deviation of the canal, no two groups were significantly different at the 0.05 level. (P > 0.05) 3. In the evaluation of debris scores, ultrasonic and sonic groups were better debridement effect than hand group in the fine canals. In the large canals, ultrasonic group was the best results, followed by sonic, hand group. 4. In the evaluation of smear layer scores, ultrasonic group was the best and sonic and hand group were same effect in the fine canals. In the large canals, three groups were same effect. 5. In the effect of the removal of predentin and pulpal debris, in the regardless of canal size, three groups were same and pulpal debris was not completely removed by either technique.

• Restorative Dentistry and Endodontics
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• 제37권4호
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• pp.220-227
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• 2012

Objectives: The study was to compare the shaping ability of Reciproc (VDW) and WaveOne (Dentsply Maillefer) instruments compared with ProTaper, Profile and hand instrument during the preparation of simulated root canals. Materials and Methods: Five groups (n = 5) were established. Reciproc, WaveOne, ProTaper, Profile and K file (K-flexo file) were used to prepare the resin simulated canals. A series of preoperative and postoperative images were taken by a microscope and superimposed in 2 different layers. The amount of resin removed from both the inner and the outer sides of the canal was measured to the level of 10 mm from the apical tip, with a 1 mm increment. Results: The mean of resin removal from the inner canal wall was not different from the outer canal wall for Reciproc and WaveOne groups at apical third (1 - 3 mm level). There was no difference in the change of working length and maintenance of canal curvature. NiTi instruments are superior to stainless-steel K file in their shaping ability. Conclusions: Within the limitation of this present study, Reciproc and WaveOne instruments maintained the original canal curvature in curved canals better than ProTaper and Profile, which tend to transport towards the outer canal wall of the curve in the apical part of the canal.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 춘계학술대회 논문집
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• pp.647-648
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• 2006

The length of root canal has to be measured to cure root canal. Several apex locators were developed to measure the length of root canal. And they were verified by X-ray or micrometer method. But these methods do not consider the non-linear bends of pulp and have ${\pm}0.5mm$ error which is large to measure the length of root canal. The purpose of this study is the research of new method to measure the length of root canal and verifying the apex locator using Micro-CT. The length of root canal of 6 teeth were measured with the apex locator. When the apex locator reads 0.5, 0.6, 0.7, 0.5, 0.9, 1.0mm, the teeth with the file fixed were photographed. The average lengths of root canal of 6 teeth measured by Micro-CT were 0.488, 0.589, 0.680, 0.775, 0.897, 0.992mm.

• Clinical and Experimental Pediatrics
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• 제55권4호
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• pp.143-146
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• 2012

The processus vaginalis within the inguinal canal forms the canal of Nuck, which is a homolog of the processus vaginalis in women. Incomplete obliteration of the processus vaginalis causes indirect inguinal hernia or hydrocele of the canal of Nuck, a very rare condition in women. Here, we report 2 cases of hydrocele of the canal of Nuck that were diagnosed with ultrasonography in both cases and magnetic resonance imaging in 1 case to confirm the sonographic diagnosis. High ligation and hydrocelectomy were conducted in both patients. In 1 patient, 14 months later, the occurrence of contralateral inguinal hernia was suspected, but did not require surgery. The other patient had a history of surgery for left inguinal hernia 11 months before the occurrence of right hydrocele of the canal of Nuck. In both cases, the occurrence of an inguinal hernia on the contralateral side was noted.

• Restorative Dentistry and Endodontics
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• 제16권1호
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• pp.167-180
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• 1991

The purpose of theis study was to evaluate the effectiveness of ultrasonic instrumentation in removing debris and smear layer from the root canal walls. 54 extracted, permanent single rooted teeth were randomly divided into 6 groups of 9 teeth. After canal preparation, the teeth were longitudinally sectioned. The sepcimens were then naturally dried for 2 days, given a maximun thickness gold coating, and examined under the SEM (JSM-35C type, JAPAN). Photographs of all specimens were then taken of the middle and the apical third of the root canal wall. The results were as follows: 1. In all groups, debris and the smear layer were not completely removed from the canal wall 2. There were no significant differences between at the apical third and at the middle third in removing debris and the smear layer in all groups. 3. There were no significant difference between the step - back group and the ultrasound group in removing debris and smear layer. 4. In general, the step - back/ultrasonund groups showed greater canal debridement than the step - back group or ultrasound group. 5. The step - back/ultrasound group with a No. 25 file for 3 min. showed significantly greater canal debridement than the step-back group (p<0.05), or the other step - back/ultrasound groups(p<0.05).

• Imaging Science in Dentistry
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• 제39권2호
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• pp.89-92
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• 2009

Purpose: To assess the angle between mandibular canal and occlusal plane at each posterior tooth region and location of mental foramen on the panoramic radiographs. Materials and Methods: This study analysed 46 half-mandibles of panoramic radiographs. Inferior border of mandibular canal was traced. Occlusal plane was drawn from lingual cusp tip of the first premolar to distolingual cusp tip of the second molar. Perpendicular line from occlusal plane was drawn at each tooth region and then tangential lines were drawn from the crossing points at canal. the angle between occlusal plane and tangential line was measured. The location of mental foramen was also studied. According to the location of mental foramen, radiographs were divided into M (mesial) group and D (distal) group on the basis of the second premolar. and then inter-group analysis about mandibular canal angle was done. Results: The angles of mandibular canals were -17.7$^{\circ}$, -9.5$^{\circ}$, 8.2$^{\circ}$, 22.3$^{\circ}$, and 39.2$^{\circ}$at first premolar, second premolar, first molar, second molar, and third molar, respectively. The commonest position of the mental foramen was distal to the second premolar. Inter-group comparison showed statistically significant difference at the second premolar and the first molar(p<0.001). Conclusion: The knowledge of mandibular canal angle and location of mental foramen can help understanding the course of mandibular canal. (Korean J Oral Maxillofac Radiol 2009; 39: 89-92)

• Restorative Dentistry and Endodontics
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• 제40권3호
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• pp.241-248
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• 2015

Variation in root canal morphology, especially in maxillary first molar presents a constant challenge for a clinician in their detection and management. This case report describes the successful root canal treatment of a three rooted right maxillary first molar presenting with three canals each in the mesiobuccal and distobuccal roots and one canal in the palatal root. The clinical detection of this morphologic aberration was made using a dental operating microscope, and the canal configuration was established after correlating and computing the clinical, radiographic and cone-beam computed tomography (CBCT) scan findings. CBCT images confirmed the configuration of the canals in the mesiobuccal and distobuccal roots to be Al-Qudah and Awawdeh type (3-2) and type (3-2-1), respectively, whereas the palatal root had a Vertucci type I canal pattern. This report reaffirms the importance of careful examination of the floor of the pulp chamber with a dental operating microscope and the use of multiangled preoperative radiographs along with advanced diagnostic aids such as CBCT in identification and successful management of aberrant canal morphologies.

• Journal of Korean Dental Science
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• 제14권2호
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• pp.61-68
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• 2021

Purpose: The aim of this study was to investigate the outcomes of endodontic treatment of mandibular second molar with C-shaped canal in elderly patients and related factors affecting the survival of the tooth. Materials and Methods: From 2010 to 2015, the survival rate following endodontic treatment was evaluated in elderly patients over 60 years who visited the Veterans Health Service Medical Center for endodontic treatment. The presence of C-shaped canals was confirmed using clinical records and radiographic features. Patient's age, sex, systemic diseases, tooth location, vitality, signs and symptoms, fractures, caries, apical radiolucency, canal shaping methods, sealer leakage, filling voids, and restoration of prosthesis were included in the analyses as confounding variables. The survival rate of teeth was analyzed using Kaplan-Meire analysis and the relationship between the survival rate and variables was analyzed using Simple and Multiple Cox regression analysis. Result: In total, 107 teeth in elderly patients had C-shaped canal. The survival rate of teeth that received endodontic treatment was 63.70%. None of the factors investigated significantly influenced the survival rate (P>0.05). Conclusion: In elderly patients with C-shaped canal, the survival rate after root canal treatment was not significantly different from that of other mandibular molars.