• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.28 no.2
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• pp.471-489
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• 1998

For the successful endodontic treatment, root canal should be cleaned thoroughly by accurate mechanical and chemical canal preparation and sealed completely with canal filling material without damaging the periapical tissues. The accuracy of the root canal length measurement is a prerequisite for the success of the endodontic treatment, and the root canal length is often determined by the standard periapical radiographs and digital tactile sense. In this study, the accuracy and the clinical usefulness of Digora/sup (R)/, an intraoral digital imaging processor and the conventional standard radiographs were compared by measuring the length from the top of the file to the root apex. 30 single rooted premolars were invested in a uniformly sized blocks and No.25 K-file was inserted into and fixed in each canal. Each block was placed in equal distance and position to satisfy the principle of the bisecting angle and paralleling techniques and Digora/sup (R)/ system's image and standard periapical radiographs were taken. Each radiograph was examined by 3 different observers by measuring the length from top of the file to the root apex and each data was compared and analyzed. The results were as follows; 1. In the bisecting angle technique, the average difference between the Digora/sup (R)/ system and standard periapical radiograph was 0.002 mm and the standard deviation was 0.341 mm which showed no statistically significant difference between the two systems(p>0.05). Also, in the paralleling technique, the average difference between these two system was 0.007 mm and the standard deviation was 0.323 mm which showed no statistically significant difference between the two systems(p>0.05). 2. In Digora/sup (R)/ system, the average difference between the bisecting angle and paralleling technique was -0.336 mm and the standard deviation was 0.472 mm which showed a statistically significant difference between the two techniques(p<0.05). Also, in the standard periapical radiographs, the average difference between the bisecting angle and paralleling technique was 0.328 mm and the standard deviation was 0.517 mm which showed a statistically significant difference between these two techniques(p<0.05). 3. In Digora/sup (R)/ system and the standard periapical radiographs. there was a statistically significant difference between the measurement using the bisecting angle technique and the actual length(p<0.05), But there was no statistically significant difference between the measurement using the paralleling technique and the actuallength(p>0.05). In conclusion. the determination of the root canal length by using the Digora/sup (R)/ system can give us as good an image as the standard periapical radiograph and using the paralleling technique instead of the bisecting angle technique can give a measurement closer to the actual canal length. thereby contributing to a successful result. Also. considering the advantages of the digital imaging processor such as decreasing the amount of exposure to the patient. immediate use of the image. magnification of image size. control of the contrast and brightness and the ability of storing the image can give us good reason to replace the standard periapical radiographs.

• Restorative Dentistry and Endodontics
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• v.44 no.4
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• pp.40.1-40.10
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• 2019

Objectives: This study aimed to assess the effect of DentalVibe on the level of pain experienced during anesthetic injections using 2 different techniques. Materials and Methods: This randomized crossover clinical trial evaluated 60 patients who required 2-session endodontic treatment. Labial infiltration (LI) anesthesia was administered in the anterior maxilla of 30 patients, while inferior alveolar nerve block (IANB) was performed in the remaining 30 patients. 1.8 mL of 2% lidocaine was injected at a rate of 1 mL/min using a 27-gauge needle. DentalVibe was randomly assigned to either the first or second injection session. A visual analog scale was used to determine participants' pain level during needle insertion and the anesthetic injection. The paired t-test was applied to assess the efficacy of DentalVibe for pain reduction. Results: In LI anesthesia, the pain level was 12.0 ± 15.5 and 38.1 ± 21.0 during needle insertion and 19.1 ± 16.1 and 48.9 ± 24.6 during the anesthetic injection using DentalVibe and the conventional method, respectively. In IANB, the pain level was 14.1 ± 15.9 and 35.1 ± 20.8 during needle insertion and 17.3 ± 14.2 and 39.5 ± 20.8 during the anesthetic injection using DentalVibe and the conventional method, respectively. DentalVibe significantly decreased the level of pain experienced during needle insertion and the anesthetic injection in anterior LI and mandibular IANB anesthesia. Conclusions: The results suggest that DentalVibe can be used to reduce the level of pain experienced by adult patients during needle insertion and anesthetic injection.

• The Journal of the Korean dental association
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• v.57 no.11
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• pp.672-678
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• 2019

AIM: The purpose of this study was to evaluate and compare the torsional fracture resistances, cyclic fatigue resistance, and bending stiffness of two nickel-titanium (NiTi) rotary instruments made of different heat-treated alloy: Aurum Blue (heat-treated) and Aurum Pro (conventional). Methods: Forty-five Aurum Blue and Aurum Pro NiTi files were selected for the three mechanical tests (n=15). For the torsional resistance test, 3 mm file tip was fixed and the shaft was driven clockwise at 2 rpm until fracture occurred by using a customized device. Cyclic fatigue resistance was evaluated by rotating instruments in artificial canal with dynamic mode. Bending stiffness was tested by observation of the bending moment on attaining a 45° bend. The results were analyzed by student-t tests at a significance level of 95%. The fractured surface of each groups were examined under a scanning electron microscope (SEM). Results: Aurum Blue showed significantly higher toughness, ultimate strength, distortion angle, and number of cycles to failure than those of Aurum Pro (p < 0.05). However, Aurum Blue and Aurum Pro did not differ significantly in terms of bending stiffness. SEM showed typical topographic appearances of the cyclic fatigue and torsional fracture. Conclusions: Under the limitations of this study, heat-treated instruments showed higher flexibility and fracture resistances than conventional NiTi instruments.

• Restorative Dentistry and Endodontics
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• v.29 no.6
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• pp.515-519
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• 2004

Straight access cavity design allows the operator to locate all canals, helps in proper cleaning and shaping, ultimately facilitates the obturation of the canal system. However, change in the fracture strength according to the access cavity designs was not clearly demonstrated yet. The purpose of this study was to determine the influence of different access cavity designs on the fracture strength in endodontically treated mandibular anterior teeth. Recently extracted mandibular anterior teeth that have no caries, cervical abrasion, and fracture were divided into three groups (Group 1 : conventional lingual access cavity, Group 2 : straight access cavity, Group 3 : extended straight access cavity) according to the cavity designs. After conventional endodontic treatment, cavities were filled with resin core material. Compressive loads parallel to the long axis of the teeth were applied at a crosshead speed of 2mm/min until the fracture occurred. The fracture strength analyzed with ANOV A and the Scheffe test at the 95% confidence level. The results of this study were as follows: 1. The mean fracture strength decrease in following sequence Group 1 (4558.90{\;}\pm{\;}77.40{\;}N$), Group 2 ($494.07{\;}\pm{\;}123.98{\;}N) and Group 3 ($267.33{\;}\pm{\;}27.02{\;}N). 2. There was significant difference between Group 3 and other groups (P = 0.00). Considering advantage of direct access to apical third and results of this study, straight access cavity is recommended for access cavity form of the mandibular anterior teeth.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.28 no.2
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• pp.435-459
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• 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.

• Restorative Dentistry and Endodontics
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• v.22 no.1
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• pp.347-357
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• 1997

An accurate working length is an essential factor in the success of endodontic treatment. There are several methods for determining working length; electronic apex locator, tactile sense by clinician, and radiography. Among these methods, the most commonly used method is radiography. But this method requires excessive radiation, long developing time, and many equipments. In additon, it could give an image distortion and two dimensional image. To improve these disadvantages, an intraoral digital radiographic system (Digora$^{(R)}$) which use an imaging plate instead of a film, was developed. The purpose of this investigation was to compare Digora imaging with conventional radiography in determining the working length. Maxillary first or second molars of human dried skull were used. Files were inserted into canals at randomly selected lengths, from 2mm short of the radiographic apex to 2rnm beyond. Radiographs and Digora images(Digora positive and Digora negative) were evaluated to determine the adjustment needed to place the file 0.5mm from the radiographic apex. The results were as follows ; 1. There was no significant difference in accuracy between those evaluated in ${\pm}0.5mm$ and those accurately evaluated in the 3 images. 2. When comparing the accuracy of each image without distinguishing the 3 images, in the group accurately determined within ${\pm}0.5mm$, the mesiobuccal group showed significantly higher accuracy compared to the palatal group(p<0.05).

• Journal of the korean academy of Pediatric Dentistry
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• v.34 no.3
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• pp.454-460
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• 2007

Traumatic dental injuries in childhood and adolescent occurred more frequently than in adult. The time between the accident and the treatment is one of the most critical factors to prognosis, and because of the limited time available to examine and treat patients with traumatic dental injuries, if not treat appropriately, the result would be critical for the patient. In the previous studies, the prevalence and incidence of traumatic injuries were the most frequent at the age of 8 to 10 years, the majority of dental injuries involve the anterior teeth, especially the maxillary incisors, and males were more prevalent than females in an approximated proportion of 2:1. As the mean age of complete root formation is 10 years old, the maxillary permanent incisor involved in the most affected age group is usually immature, and the possibility of pulpal healing through excellent revascularization exists, more positive prognosis for pulp vitality would be expected. These are treatment cases of the immature maxillary permanent central incisor involved in the traumatic injury, and reports for progress and results of preserving the pulp vitality through the conservative treatment instead of the conventional endodontic root therapy.

• 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.

• Journal of the korean academy of Pediatric Dentistry
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• v.34 no.3
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• pp.506-512
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• 2007

Traumatic injury of tooth in children is commonly occurred problem. It is classified into tooth, periodontal tissue, supporting bone, soft tissue injury by it's area and extent. Among the periodontal tissue injuries, traumatically intruded teeth are common in anterior maxillary area, though the occurrence rate is rather low, the pulp and supporting tissue injury is possible by vertical impact. The treatment method of traumatically intruded teeth is various. Observation on the spontaneous reeruption for 3-4 weeks is recommended if the traumatized teeth are deciduous teeth or slightly intruded immature permanent anterior teeth. If this did not occur because the extent of intrusion is severe or the traumatized teeth are mature permanent anterior teeth, orthodontic traction is applied by fixed/removable appliances. At this time, light and continuous force is applied for the extrusive movement of the intruded teeth. When above procedures are impossible, surgical repositioning and fixation is recommended. In these cases, we performed conventional endodontic therapy for pulp necrosis and orthodontic traction with fixed appliance. We obtained satisfactory results and will report that.

• Journal of the korean academy of Pediatric Dentistry
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• v.44 no.1
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• pp.20-27
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• 2017

This study aimed to assess microleakage of Endoseal MTA when it is used as a root canal sealer and a root canal filling material compared with conventional endodontic treatment materials Forty-two mature human permanent teeth with a single root canal were divided randomly into three experimental groups (n = 10) and two control groups (n = 6). Group A was obturated with AH $plus^{(R)}$ and gutta-percha (GP). Group E1 was obturated with Endoseal MTA and GP. Group E2 was obturated with Endoseal MTA only. The positive control group was obturated with GP only and the negative control group was obturated in the same way as the experimental groups. The samples were kept in saline solution for 24 hours and were immersed in 0.2% rhodamine B dye solution for 24 hours. Then the samples were split longitudinally and the micoleakage was assessed under a stereomicroscope. Complete microleakage was detected in all positive control group samples, whereas no microleakage was detected in the negative control group. There was no statistically significant difference between the experimental groups in the Kruskal-Wallis test. These results suggest that Endoseal MTA has potential use as a root canal sealer and a root canal filling material.