The Journal of Japan Endodontic Association
Online ISSN : 2423-9429
Print ISSN : 1347-8672
ISSN-L : 1347-8672
Current issue
Displaying 1-8 of 8 articles from this issue
Review Articles
Original Articles
  • OGAWA Atsushi, IZUMISAWA Mitsuru, KOGI Shintaro, TAKAHASHI Noriaki, FU ...
    2024 Volume 45 Issue 3 Pages 186-190
    Published: 2024
    Released on J-STAGE: October 15, 2024
    JOURNAL FREE ACCESS

    Abstract : Purpose : The aim of this study was to evaluate the incidence of alveolar bony fenestration in a Japanese population using dental cone-beam computed tomography (CBCT).

    Materials and methods : We analyzed the CBCT images of 1,930 maxillary teeth and 1,975 mandibular teeth from 145 patients. Alveolar bony fenestration was identified as a tooth root protruding from a window-like opening or a defect in the alveolar bone without involvement of the alveolar margin.

    Results : Fenestrations were observed in 450 out of 3,905 teeth (11.5%). We found 334 fenestrations in the maxilla (17.3%) and 116 in the mandible (5.9%). Fenestrations were found most frequently on both maxillary and mandibular anterior teeth.

    Conclusion : Because 11.5% of teeth had fenestrations that could not be identified by conventional radiography, CBCT was found to be a convenient examination method for diagnosing fenestration.

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  • KATAYAMA Takuya, URABA Shintaro, BABA Satoru, SUZUKI Noriyuki
    2024 Volume 45 Issue 3 Pages 191-196
    Published: 2024
    Released on J-STAGE: October 15, 2024
    JOURNAL FREE ACCESS

    Abstract : Purpose : This study aimed to evaluate the effect of personal protective equipment (PPE) on the use of dental operating microscopes (DOMs), specifically examining how PPE such as goggles and face shields affect the field of view and resolution of the DOM.

     Materials and Methods : The study involved 10 dentists from the Department of Endodontics at Showa University School of Dentistry. The subjects were divided into three groups : no PPE (NP group), goggles (GG group), and face shield (FS group). The DOM used was the OPMI pico (ZEISS). Each participant adjusted the interpupillary distance and diopter settings before the measurements. Field diameter was measured using a custom target with concentric circles ranging from 10 to 100 mm in diameter, placed at a fixed distance of 200 mm from the objective lens. Resolution was assessed using a high-resolution target. Statistical analysis was performed using the Steel-Dwass test, with a significance level of 5%.

     Results and Discussion : The NP group had the largest field diameter and field area, followed by the GG and FS groups. Specifically, the field area was reduced to 86.7% in the GG group and 18.4% in the FS group compared to the NP group (p<0.05). There were significant differences in field diameter between the NP and GG, NP and FS, and GG and FS groups (p<0.05). However, no significant differences in resolution were observed among the three groups at any magnification level (p>0.05). The results indicate that while PPE reduces the field diameter and field area when using the DOM, it does not affect resolution. This finding underscores the importance of selecting PPE that minimizes the distance between the eyepiece and the user’s eyes to maintain an optimal field of view. Modern surgical microscopes are designed to accommodate eyeglass wearers, suggesting that appropriate PPE selection can mitigate field of view reduction. Goggles, due to their closer fit, had less effect on the field of view than a face shield.

     Conclusion : PPE reduces the field diameter and area during DOM use, with goggles having less impact than a face shield. However, PPE does not affect the resolution at any magnification level.

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  • KAMIYAMA Takahisa
    2024 Volume 45 Issue 3 Pages 197-203
    Published: 2024
    Released on J-STAGE: October 15, 2024
    JOURNAL FREE ACCESS

    Abstract : Purpose : The patient was a 77-year-old woman diagnosed with severe periodontal disease at our clinic, leading to extraction of the upper right second premolar. Upon examining the apex of the extracted tooth, we identified it as a Type 2 endodontic-periodontal lesion. Observations of cementum resorption and the state of destruction around the apical foramen allowed us to consider how the pathological condition had progressed.

     Material and Methods : We used micro X-ray CT and scanning electron microscope (SEM) to observe the microstructure of the extracted tooth.

     Results and Discussion : No caries was observed on the crown, and there were no accessory canals in the root. The apical foramen was flared, and SEM observations revealed that the cementum was resorbed inside the root canal opening, thinning due to internal resorption. This resorption resulted in thinning of the cementum, which eventually led to the formation of islands of broken and destroyed cementum. Additionally, a biofilm was observed within the apical foramen.

     From the state of destruction of the apical foramen and the presence of bacterial aggregation, this case was considered a Type 2 endo-perio lesion where bacteria had infiltrated through the apical foramen. Observing the apical foramen from the inside revealed resorption cavities, and cracks were observed in the cementum at the margin of the apical foramen. This resulted in the outward flaring of the apical foramen.

     Conclusion : In Type 2 endo-perio lesions with cracks in the cementum at the margin, it is considered difficult to achieve apical closure with conventional root canal treatment, leading to a more refractory condition. Therefore, special attention should be paid to pre-treatment explanations and treatment method decisions.

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Case Reports
  • FUKUNISHI Kazuhiro, FURUKAWA Takahiro
    2024 Volume 45 Issue 3 Pages 204-212
    Published: 2024
    Released on J-STAGE: October 15, 2024
    JOURNAL FREE ACCESS

    Abstract : Dens invaginatus, also called dens in dente, is a dental malformation caused by infolding of part of the inner enamel epithelium deeply into the underlying dental papilla and their proliferation before the morphological differentiation stage of tooth germ development. It is found in all tooth types, but is reported to occur frequently in about 3 to 10% of maxillary lateral incisors.

     Histological studies have shown that the enamel of dens invaginatus is hypomineralized, weak or defective in some cases. In addition, cracks may exist in the dentin, and there may be communication between the invagination site and the pulp. Due to such structural problems, infection rapidly reaches the pulp from the invagination site and is subsequently prone to pulpitis and apical periodontitis.

     Treatment of dens invaginatus varies according to the degree of invagination, including preventive filling treatment, endodontic treatment, surgical endodontic treatment, and tooth extraction. In the case of deep invagination, endodontic treatment is often complicated and challenging due to the complexity of the root canal morphology.

     In this study, three cases of maxillary lateral incisors classified as Type I-III in Oehlers classification were treated. In each case, we devised a treatment strategy after confirming the invagination morphology by CBCT. Treatments were performed by preventive filling treatment and endodontic treatment under the dental operation microscope. We report on satisfactory outcomes in radiographic and oral examinations, and give some considerations.

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  • HASEGAWA Tomoya, MIYAMOTO Yuka, TANAKA Masashi, KIHO Kazuki, SAKAI Chi ...
    2024 Volume 45 Issue 3 Pages 213-220
    Published: 2024
    Released on J-STAGE: October 15, 2024
    JOURNAL FREE ACCESS

    Abstract : Purpose : Horizontal root fracture is a pathological condition caused by impact on the crown of the tooth due to trauma, and often requires root canal treatment, in which case closure of the fracture part is also required. We report on the 5-year prognosis of a tooth with horizontal root fracture due to trauma, which did not cause apical periodontitis and hard tissue formation was observed at the fracture part despite inadequate root canal treatment 10 years ago.

     Case : The maxillary right central incisor had suffered trauma 10 years ago, but recently the patient came to our clinic because the discoloration of the tooth had become severe. Electric pulp test, cold test, and thermal pulp test of the incisor showed negative reactions. In addition, no percussion pain or periapical tenderness was observed. Periodontal pocket test and mobility test were within normal limits. Radiographic examination showed a fracture at the center of the root of the maxillary right central incisor, but no X-ray transmission images were observed. CBCT findings revealed a bone-like high-density image between the dissected tooth roots. Based on the clinical examination findings, the affected tooth was the maxillary right central incisor, the pulp was diagnosed as previously initiated therapy, and the apical periodontal tissue was diagnosed as normal. The cause of the discoloration was diagnosed as endogenous local discoloration due to pulp necrosis. As treatment, we decided to perform root canal treatment up to the fracture part and bleaching using the walking bleach method. The patient’s chief complaint was resolved by bleaching treatment after root canal treatment. At the 5-year postoperative follow-up, a slight reversion of the color tone was observed. Postoperative evaluation using CBCT showed that the fracture site was progressing well.

     Discussion : In this case, it was not possible to accurately determine the condition of the tooth root fracture at the time of injury. However, because 10 years had passed since the injury, there were no clinical symptoms, and there were no X-ray transmission images of the fracture or root apex, it was thought that there was almost no bacterial infection within the root canal.

     Conclusion : In the case of horizontal root fracture occurring within the bone, the progress is good if there is no bacterial infection within the root canal, reconfirming that bacterial infection is the problem with endodontic treatment.

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