• Speech Sciences
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• v.7 no.4
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• pp.83-90
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• 2000

The purpose of this study was to examine some acoustic characteristics in the ear canal. It was assumed that a sound outside the external auditory canal could be different from the sound inside the external auditory canal. The acoustic signals were captured by a probe microphone placed at a distance within 1 cm from the tympanic membrane, and a reference microphone was placed over the upper pinna. Three vowels /a/, /i/, /u/ were recorded from a normal adult male speaker. The parameters such as the formant frequency ($Fl\simF5$) and the peak intensity were measured using a speech analyser, PCquirer. It was found that the entering part of the external auditory canal functions as a narrowing point as to the speech that passes through the free field. Results show that acoustic characteristics were changed for speech discrimination rather than speech perception.

• Restorative Dentistry and Endodontics
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• v.6 no.1
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• pp.105-107
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• 1980

A total of 125 extracted maxillary first molars were used to study the configuration of the floor of the pulp chamber. The specimens were ground and the pulp chamber was examined with a magnifying glass and explored with sharp explorer. The study showed the shape of the pulp chamber, number of root canals, and type of canal orifice. The results were as follows; 1. In so far as observing the shape of the pulp chamber of the teeth, 50.4% of the teeth were trapezoid, 20.8% were inverted trapezoid, 18.4% were rectangle and 10.4% were triangle shape. 2. 71.2% of the specimens have 3 root canal orifices, and 28.8% have 4 root canal orifices. 3. 71.2% of the specimens have 1 mesiobuccal canal orifice, 23.2% have 2 mesio-buccal canal orifices joined by a groove, and 5.6% have 2 mesio-buccal canal orifices seperated each other.

• Proceedings of the KACD Conference
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• 2003.11a
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• pp.595-595
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• 2003

I. Objectives This study was done to evaluate which type of Ni-Ti instrument be able to perform canal shape well in the simulated canal with abrupt curvature near it's apex. II. Materials and Methods A total of 96 simulated root canals were made in epoxy resin(EPOXICURETM, BUEHLER, USA), ＃15 finger spreader (MANI, Japan) were used as root canal templates. The simulated root canal were made with radius of curvature of 1.5 mm, 3.0 mm, 4.0 mm, 6.0 mm respectively, and angle of curvature of all simulate camals was 90 degree.(omitted)

• Restorative Dentistry and Endodontics
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• v.17 no.2
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• pp.413-420
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• 1992

The purpose of this study was to compare the effectiveness of hand instrumentation with K - file and ultrasonic instrumentation and irrigation system in removing pulpal debris and canal wall planing. 20 mandibular molar teeth were instrumented to size 30 K - file and 20 teeth were instrumented with ultrasonic Suprasson. And Normal Saline and 2.5% NaOCl were used as irrigation solution. All specimens were viewed at the coronal, middle, and apical third of the root canals for the evaluation of the cleaning effect under the multiview microscope. The result were as follows : 1. All of the technique and irrigation solution was effecient in the debris removal and canal wall planing at the cervical and middle thirds of the root canal. 2. All of the techniques and irrigation solutions was less efficient in the debris removal and canal planing at the apical third of the root canal. 3. The debris removal and canal wall planing was depended more on the anatomical variations of the root canal than on the techniques and irrigation solutions.

• Restorative Dentistry and Endodontics
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• v.49 no.2
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• pp.16.1-16.10
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• 2024

Objectives: This cross-sectional study evaluated the prevalence of apical periodontitis (AP) and the technical quality of root canal fillings in an adult Kuwaiti subpopulation using cone-beam computed tomography (CBCT) images. Materials and Methods: Two experienced examiners analyzed 250 CBCT images obtained from Kuwaiti patients aged 15-65 years who attended government dental specialist clinics between January 2019 and September 2020. The assessment followed the radiographic scoring criteria proposed by De Moor for periapical status and the technical quality of root canal filling. Chi-square and Fisher's exact tests were used for statistical analysis, with significance level set at p < 0.05. Results: Among the 2,762 examined teeth, 191 (6.91%) exhibited radiographic signs of AP, and 176 (6.37%) had undergone root canal filling. AP prevalence in root canal-treated teeth was 32.38%, with a significant difference between males and females. Most of the endodontically treated teeth exhibited adequate root canal filling (71.5%). Conclusions: The study demonstrated a comparable prevalence of AP and satisfactory execution of root canal treatment compared to similar studies in different countries.

• The Journal of the Korean dental association
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• v.56 no.5
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• pp.254-262
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• 2018

Objectives: This study aimed to compare the postoperative pain and clinical performance after applying three different intracanal medicaments and root canal sealers. Materials and Methods: Sixty-five patients requiring root canal treatment due to symptomatic apical periodontitis were included in this study. After a glide path preparation by using PathFile, each canal was shaped with ProTaper Next file system. After the canal cleaning and shaping procedure, the canal was dried and each intracanal medicaments were adjusted (Calcipex II, TRC-paste, Metapaste). At the next visit, the patients were requested to answer the absence of the pain after the procedure. Once the patients showed no symptom, the canal was obturated with each corresponded root canal sealers (AH plus, Radic-sealer, ADseal). The patients were recalled after 1 week, 1, 3, and 6 months to check the postoperative pain or unexpected clinical signs. One-way ANOVA and Duncan's post hoc comparison, and Chi-square test were used for statistical analysis to evaluate any differences among tested materials. Results: The average number of visits for intracanal medication was 2.69, 2.65, and 2.61 for Calcipex II, TRC-paste, and Metapaste. There were no statistically differences in post-obturation pain among three groups obturated with different root canal sealers (P > 0.05). Conclusions: Under the limitations of this study, three tested intracanal medicaments and epoxy resin root canal sealers showed clinically acceptable similar results.

• Imaging Science in Dentistry
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• v.44 no.4
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• pp.273-278
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• 2014

Purpose: This study was performed to investigate the course of the mandibular canal on panoramic radiography and the visibility of this canal on both panoramic radiography and cone-beam computed tomography (CBCT). Materials and Methods: The study consisted of panoramic radiographs and CBCT images from 262 patients. The course of the mandibular canal, as seen in panoramic radiographs, was classified into four types: linear, elliptical, spoon-shaped, and turning curves. The visibility of this canal from the first to the third molar region was evaluated by visually determining whether the mandibular canal was clearly visible, probably visible, or invisible. The visibihlity of the canal on panoramic radiographs was compared with that on CBCT images. Results: Elliptical curves were most frequently observed along the course of the mandibular canal. The percentage of clearly visible mandibular canals was the highest among the spoon-shaped curves and the lowest among the linear curves. On panoramic radiographs, invisible mandibular canals were found in 22.7% of the examined sites in the first molar region, 11.8% in the second molar region, and 1.3% in the third molar region. On CBCT cross-sectional images, the mandibular canal was invisible in 8.2% of the examined sites in the first molar region, 5.7% in the second molar region, and 0.2% in the third molar region. Conclusion: The visibility of this canal was lower in the first molar region than in the third molar region. The mandibular canal presented better visibility on CBCT images than on panoramic radiographs.

• Restorative Dentistry and Endodontics
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• v.43 no.1
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• pp.3.1-3.10
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• 2018

Objectives: The aim of this study was to compare root canal volume change and canal transportation by Vortex Blue (VB; Dentsply Tulsa Dental Specialties), ProTaper Next (PTN; Dentsply Maillefer), and ProTaper Universal (PTU; Dentsply Maillefer) nickel-titanium rotary files in curved root canals. Materials and Methods: Thirty canals with $20^{\circ}-45^{\circ}$ of curvature from extracted human molars were used. Root canal instrumentation was performed with VB, PTN, and PTU files up to #30.06, X3, and F3, respectively. Changes in root canal volume before and after the instrumentation, and the amount and direction of canal transportation at 1, 3, and 5 mm from the root apex were measured by using micro-computed tomography. Data of canal volume change were statistically analyzed using one-way analysis of variance and Tukey test, while data of amount and direction of transportation were analyzed using Kruskal-Wallis and Mann-Whitney U test. Results: There were no significant differences among 3 groups in terms of canal volume change (p > 0.05). For the amount of transportation, PTN showed significantly less transportation than PTU at 3 mm level (p = 0.005). VB files showed no significant difference in canal transportation at all 3 levels with either PTN or PTU files. Also, VB files showed unique inward transportation tendency in the apical area. Conclusions: Other than PTN produced less amount of transportation than PTU at 3 mm level, all 3 file systems showed similar level of canal volume change and transportation, and VB file system could prepare the curved canals without significant shaping errors.

• Imaging Science in Dentistry
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• v.38 no.3
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• pp.163-167
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• 2008

Purpose : The purpose of this study is to evaluate the position of the mandibular canal in relation to the mandibular third molar by cone beam CT in cases showing a close relationship between the third molar and the mandibular canal on the panoramic radiograph. Materials and Methods : The panoramic images and cone beam CT scans of 87 impacted mandibular third molars in 60 patients were evaluated to assess the tooth relationship to the mandibular canal. The clearness of the canal wall and the vertical depth of the lower third molar were evaluated on panoramic radiographs. The lower third molars were assessed using cone beam CT to determine the proximity and position of the canal relative to the roots. Results : In the 66 cases where the canal wall was unclear on the panoramic radiographs, 58 (87.9%) of the third molars had contact between the canal and root; 34 (51.5%) canals were showed an inferior position and 22 (33.3%) showed a linguoinferior position on cone beam CT. Conclusion : Interruption of the canal wall on panoramic radiographs was highly predictive of contact between the mandibular canal and the third molar. Cross sectional CT may be indicated for localization of the mandibular canal in such cases.

• Imaging Science in Dentistry
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• v.51 no.1
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• pp.35-40
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• 2021

Purpose: This study was conducted to evaluate the accuracy of cone-beam computed tomography (CBCT) in detecting the posterior superior alveolar(PSA) artery canal in a sample of the Egyptian population. Materials and Methods: CBCT images of 600 maxillary sinuses of patients were examined for the presence or absence of the PSA artery along the lateral wall of the maxillary sinus, and for the diameter and type of the canal in relation to age and sex. The distances from the canal to the alveolar crest and sinus floor were also measured. Each canal was assessed to determine whether it was bifid. Results: The PSA artery canal could be detected in 92.0% of the sinuses. The mean distance from the inferior border of the PSA artery canal to the sinus floor was 8.2±2.2 mm (range, 3.2-13.6 mm) in males and 7.3±2.1 mm (range, 3.0-13.1 mm) in females. The mean distance from the inferior border of the PSA artery canal to the alveolar crest was 18.2±2.7 mm (range, 11.0-23.9 mm) in males and 17.4±2.3 mm (range, 10.8-23.5 mm) in females. The mean diameter of the PSA artery canal was larger in male subjects. The PSA artery canal was bifid in 8.7% of cases. The most frequently observed location of the PSA artery canal was intraosseous(82.2%). Conclusion: CBCT was confirmed to be a valuable tool for evaluation and localization of the PSA artery before maxillary sinus lift surgery to avoid intraoperative bleeding.