Annals of Japan Prosthodontic Society
Online ISSN : 1883-6860
Print ISSN : 1883-4426
ISSN-L : 1883-4426
Volume 3, Issue 2
Displaying 1-14 of 14 articles from this issue
Invited Articles
  • Takayuki Takeda, Yoshiharu Hayashi
    2011 Volume 3 Issue 2 Pages 97-107
    Published: April 10, 2011
    Released on J-STAGE: April 21, 2011
    JOURNAL FREE ACCESS
    Applying as little load as possible to protect osseous tissue around the dental implant has been considered as the most important element especially during the osseointegration period. Therefore the patients' QOL might be unwillingly sacrificed during this period. Moreover, the management of occlusal function (or occlusal relationships) is believed lower priority, and often is deferred until a later time once osseointegration is obtained.
    However, maintaining patients' QOL even during the healing period ought to be given higher priority as well as nutritional care and wound healing. Furthermore, in case of numerous teeth loss, maintaining stable centric occlusion from the beginning to the end of the treatment period and positioning the mandible adequately in a limited time period are important to avoid any mechanical complications.
    Consequently, the purpose of this paper is to indicate the basic principle of providing occlusal contacts on the provisional and final restorations; also suggested are some strategies and precautions to ensure success for the management of mastication function during the healing period.
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  • Yoshinori Nameta
    2011 Volume 3 Issue 2 Pages 108-118
    Published: April 10, 2011
    Released on J-STAGE: April 21, 2011
    JOURNAL FREE ACCESS
    To achieve satisfactory esthetic results in patients is an important challenge for dentists. To maintain esthetic results is difficult from the view of prevention of prosthesis collapse and of marginal tissue recession.
    First, the dentist and dental technician deliver the final restorations that harmonize with the esthetic zone of the patient. Second, the dentist attempts to prevent marginal tissue recession after delivery of the final restorations. To maintain healthy gingival tissue is also difficult, so it is necessary to understand the natural features of tissue surrounding intact teeth and implants.
    This article discusses differences between intact teeth and implants. The regeneration characteristics of supra-alveolar fiber apparatus surrounding the tooth and implant, also reveals the importance of the portion of penetrating mucosa that connects to the root or prosthesis directly. Some clinical approaches to the above issues are presented.
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  • —Key Points of Layering Method and Press Method—
    Kazunobu Yamada
    2011 Volume 3 Issue 2 Pages 119-125
    Published: April 10, 2011
    Released on J-STAGE: April 21, 2011
    JOURNAL FREE ACCESS
    CAD/CAM applications in the prosthodontic field have expanded through improved scanning accuracy, design freedom, operation and dental technicians' efforts. The manufacturing and reproduction accuracy of the copings and frameworks has been progressing day by day. Furthermore, the materials to be used for milling are varied such as wax, resin, metals, ceramics and others. The quality of each material itself has been developing.
    Yttria-stabilized zirconia with a single-phase crystal has a good biocompatibility as well as an excellent flexural strength. This material now is being studied as a new material for clinical cases for which we could not have expected good results before. However, because this is a new material and technique, we have not yet established the knowledge and know-how for the aesthetic restoration, making the most of this excellent material. At present, the information is not sufficient as to the acquisition of the aesthetics which is well-balanced with the surrounding periodontal tissues, and also as to the stable technique on a long term basis which enables the acquisition.
    In this paper, the author is going to discuss with the clinical steps what dental technicians should note when they use zirconia material in the their cases.
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Original Articles
  • Kazumasa Nishimura, Takashi Ohi, Masaki Takatsu, Yoshinori Hattori, Ak ...
    2011 Volume 3 Issue 2 Pages 126-134
    Published: April 10, 2011
    Released on J-STAGE: April 21, 2011
    JOURNAL FREE ACCESS
    Purpose: We conducted a 1-year cohort study in a community-dwelling elderly population to investigate associations between the possession of ≥ 20 teeth and onset of mild cognitive impairment (MCI).
    Methods: A community-based comprehensive geriatric assessment including measurements of physical, mental, oral, and social functioning was conducted in elderly people aged ≥ 70 years in a suburban area of Sendai, Japan. Of 1,198 participants in baseline survey, 557 individuals (females, N=310) who had normal cognition at baseline and took part in the follow-up survey were included in the analysis. Cognitive function was evaluated by Mini-Mental State Examination (MMSE) with a cutoff of 25/26 and subjects were classified as normal (MMSE ≥ 26) or having MCI (MMSE ≤ 25). We also assessed body mass index, history of stroke, myocardial infarction, hypertension, and diabetes, smoking, alcohol consumption, depressive symptoms, duration of education, marital status, social support, physical activity and self-assessed health as confounding factors for onset of MCI.
    Results: Multiple logistic regression analysis indicated that possession of ≥ 20 teeth was independently associated with decreased risk of MCI in elderly men. The odds ratio (95% Confidence Interval) of possession of ≥ 20 teeth for onset of MCI was 0.19 (0.04-0.82).
    Conclusions: Our findings suggest that possession of ≥ 20 teeth might be advantageous to prevent cognitive impairment as well as masticatory dysfunction.
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  • Mutsumi Takahashi, Kaoru Koide, Fumi Mizuhashi, Osami Morita
    2011 Volume 3 Issue 2 Pages 135-143
    Published: April 10, 2011
    Released on J-STAGE: April 21, 2011
    JOURNAL FREE ACCESS
    Purpose: The usefulness of mouthguard to prevent stomatognathic injury during sports depends on the materials and the thickness of the mouthguard. The aim of this study was to investigate the thickness of mouthguard sheet after vacuum forming based on the shape of the mouthguard sheet during heating conditions.
    Methods: Cross stripes (10 × 10 mm) were printed in mouthguard sheets. The thickness of each cross stripe area was measured by measuring device. The plaster cast was trimmed to the height of 20 mm at the incisal edge of the upper central incisor and 15 mm at the medial buccal cusp of the upper first molar. The sheets were heated until they sagged 10, 15, and 20 mm from baseline by vacuum former. Two shapes of the sheet were compared as follow: Impactguard® grooved sheet (IM-G) and flat sheet (IM-F). The difference in the ratio of change of thickness depending on the shapes of the sheet and the heating conditions was analyzed by two-factor ANOVA.
    Results: The change of thickness in the part of the sheet fitted to the anterior teeth and posterior teeth of IM-G was smaller than that of IM-F. The change of thickness was influenced by the heating conditions.
    Conclusions: This study suggests that the thickness of mouthguard sheet after vacuum forming was affected by the shape of the sheet, and the grooved sheet could secure the thickness in the part of the anterior teeth and posterior teeth of mouthguard sheet.
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  • Toshiko Sawada, Yasuhiro Nageishi, Noritaka Sako, Fumiko Takita, Yoshi ...
    2011 Volume 3 Issue 2 Pages 144-153
    Published: April 10, 2011
    Released on J-STAGE: April 21, 2011
    JOURNAL FREE ACCESS
    Purpose: The present study aimed to evaluate the discomfort of mouth guards (MGs) by using two objective physiological measures.
    Methods: Fifteen healthy male students (age, 19-28 years) participated. We recorded salivary activity of α-amylase (enzyme activity) and heart rate variability by measuring of R-R intervals. Subjective questionnaire assessments for their comfort were also measured by visual analog scale method. Each parameter was recorded while subjects wore large, middle, or small MGs. The large MG was the covered palate type. We cut along the 4-mm outer cervical line to make the medium MG, and along the cervical line to make the small MG. The three sets of parameters were assessed on consecutive 2 days. Salivary α-amylase was measured four times for each MG type: immediately before inserting the MG, 3 min after insertion, immediately after removal, and 3 min after removal. Heart rate variabilities [HF: high-frequency component, LF (low-frequency component)/(HF+LF) × 100] were measured during two periods for each MG type: 90 sec period immediately before insertion and 60 sec period during wear. After removing each MG, participants answered a questionnaire consisting of five items: ease of breathing, dry mouth, sensation of a foreign object, usability during sports and tongue sensation.
    Results: Salivary α-amylase levels increased significantly with all types of MG, particularly for the large MG during the wear and immediately after removal. In HF, there was no significant differences between pre-insertion and insertion for any MGs. However, LF/(HF+LF) × 100 increased while participants wore any MGs. Especially, it for large MG was significantly higher than those for other two MGs. The questionnaires showed significant differences among the MG types. In particular, the large MG was more uncomfortable than the other two.
    Conclusion: Our results suggest that small and middle MGs are more comfortable than large ones.
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Case Reports
  • Koh Kaneda
    2011 Volume 3 Issue 2 Pages 154-157
    Published: April 10, 2011
    Released on J-STAGE: April 21, 2011
    JOURNAL FREE ACCESS
    Patient: The patient was a 72-year-old woman with chronic periodontitis and tooth mobility. She refused to undergo surgery for tooth extraction. She already wore removable partial denture and several crowns and had dissatisfaction about aesthetics of her oral condition. Therefore we applied her conical crown-retained denture.
    Discussion: The conical crown-retained denture had good prognosis for 8 years because this denture has a rigid support and a sprinting effect of remaining teeth.
    Conclusion: It was recognized that conical crown-retained denture was effective as final prosthesis in a chronic periodontal patient with tooth mobility.
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  • Akiko Hosogai
    2011 Volume 3 Issue 2 Pages 158-161
    Published: April 10, 2011
    Released on J-STAGE: April 21, 2011
    JOURNAL FREE ACCESS
    Patient: 62-year-old female requiring correction of unaethestic prosthesis on the midline diastema. Molar occlusion was first established with a removable partial denture then the diastema was closed by retraction of the upper anterior teeth by means of a partial brace.
    Discussion: Since the dental occlusion had been established and the tension of the upper lip was strong, the diastema was closed by retraction of the anterior teeth. During the dynamic treatment period the gap between canine and premolar did not extend. No relapse has been observed during the 4.5 years since the final restoration.
    Conclusion: Symmetric correction of this diastema case could not be achieved by prosthesis alone. Therefore prosthodontic pretreatment of minor movement of teeth was applied resulting in satisfactory long-term functional stable oral environment.
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  • Miki Ryuzaki
    2011 Volume 3 Issue 2 Pages 162-165
    Published: April 10, 2011
    Released on J-STAGE: April 21, 2011
    JOURNAL FREE ACCESS
    Patient: A 60-year-old female complained of pain of the palatine mucosa during mastication. A few years ago, she received a removable partial denture although she sensed incongruity and did not use it at all. Then, her lower anterior teeth started to bite into palatine mucosa, and she became conscious of pain. The occlusal vertical dimension was increased in prosthetic restoration to relieve it.
    Discussion: For setting of occlusal vertical dimension, multiple data such as results of lateral cephalometric analysis were referred. Therefore a prosthetic restoration without the sense of incongruity could be constructed.
    Conclusion: Lateral cephalometric analysis is useful in the setting of occlusal vertical dimension.
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  • Shota Ichinose
    2011 Volume 3 Issue 2 Pages 166-169
    Published: April 10, 2011
    Released on J-STAGE: April 21, 2011
    JOURNAL FREE ACCESS
    Patient: The patient was a 71-year-old female who visited our dental office. Her chief complaint was that of dissatisfaction with her anterior dental esthetics. Predictable prosthetic treatment with occlusal reconstruction was performed using a relined removable denture. Final restoration was made with a fixed ceramic bridge and ovate pontic for esthetic recovery.
    Discussion: A fixed bridge with an ovate pontic could avoid alveolar bone disruption and also maintain the papilla shape as well as the gum level appropriately.
    Conclusion: A fixed bridge with ovate pontic was deemed an appropriate treatment for the patient who was previously complaining about anterior dental esthetics.
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  • Hiroyuki Kibayashi
    2011 Volume 3 Issue 2 Pages 170-173
    Published: April 10, 2011
    Released on J-STAGE: April 21, 2011
    JOURNAL FREE ACCESS
    Patient: The patient was a 58-year-old woman who had chronic periodontitis and morphological and functional complex dysfunction. Various problems were solved by integrated preprosthetic treatments such as minor tooth movement and periodontal surgery which included periodontal regeneration therapy. Afterwards, posterior occlusal reconstruction was carried out, and the patient's oral condition considerably improved with regards to oral hygiene and function.
    Discussion: When extensive prosthetic treatment such as in this case is carried out, it is necessary to decide the efficient treatment order based on an accurate diagnosis. Four years have passed since definitive restorations were placed. Maintenance therapy and oral hygiene instruction are continuously given to the patient every 6 months to keep the excellent oral condition.
    Conclusion: This case shows the importance of integrated preprosthetic treatments to enable good prognosis.
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  • Misaki Jinnouchi
    2011 Volume 3 Issue 2 Pages 174-177
    Published: April 10, 2011
    Released on J-STAGE: April 21, 2011
    JOURNAL FREE ACCESS
    Patient: A 61-year-old female complained of masticatory dysfunction of maxillary and mandibular removable partial denture. During the treatment she asked for much progress with masticatory function and improvement of articulation disorder caused by maxillary partial denture. Then implant supported fixed prostheses were selected for maxillary and mandibular rehabilitation.
    Discussion: During follow-up, implant supported fixed prosthesis ((4)32(1)|1(2)) became debonded. However, no significant problem occurred after cementation. Definitive prosthesis of implants beyond 3 years after treatment preserves occlusal function.
    Conclusion: Implant treatment for this partially edentulous patient was more effective for recovery and preservation of occlusal function than removable partial denture.
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  • Hideyuki Koike
    2011 Volume 3 Issue 2 Pages 178-181
    Published: April 10, 2011
    Released on J-STAGE: April 21, 2011
    JOURNAL FREE ACCESS
    Patient: A 59-year-old woman visited our clinic presenting with inadequate occlusal support on the right side resulting from non-use of the cone-crown retained denture in the mandibular right molar region. To improve the patient's quality of life (QOL), the occlusal plane was corrected by minor tooth movement, and the occlusion was reconstructed using implants.
    Discussion: The ideal occlusal plane for prosthetic treatment was determined before initiating treatment. Based on this occlusal record, the provisional restoration was replaced by the final prosthesis and it was possible to achieve a stable intraoral environment with minimum discomfort.
    Conclusion: Correction of the occlusal plane and use of an implant-supported prosthesis effectively improved the QOL in this patient with unilateral loss of occlusal support in the molar region.
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  • Shigeo Tanaka
    2011 Volume 3 Issue 2 Pages 182-185
    Published: April 10, 2011
    Released on J-STAGE: April 21, 2011
    JOURNAL FREE ACCESS
    Patient: A 67-year-old female patient presented with chief complaints of occlusal bite and esthetic appearance disorder due to a decrease in the vertical dimension of occlusion. The bite was diagnositically restored using an occlusal splint appliance. Provisional restorations were then placed and gradually adjusted to establish optimum treatment relationships of occlusal vertical dimension, periodontal health, and esthetic appearance. The final restorations were then completed for the maxillary and mandibular arches with metal-ceramic PFM crowns.
    Discussion: The patient was satisfied with esthetic and functional results of the completed rehabilitation. However, a protective postrestoration occlusal splint and regular periodic reevaluation are required to reassess any continued nocturnal parafunction during sleep.
    Conclusion: Prosthetic restorative stability requires diagnostic and evaluative stabilization of the temporomandibular joint, supporting tissues, and occlusion. A long-term provisional restoration helps to determine the ultimate potential of restorative stability in the temporomandibular joint and occlusion gained by reconstructive prosthetic treatment.
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