Journal of Prosthodontic Research
Online ISSN : 1883-9207
Print ISSN : 1883-1958
ISSN-L : 1883-1958
Volume 61, Issue 1
Displaying 1-13 of 13 articles from this issue
Editorial
Letter to the Editor
Review
  • Agnieszka Tarkowska, Lukasz Katzer, Marcus Oliver Ahlers
    2017 Volume 61 Issue 1 Pages 9-19
    Published: 2017
    Released on J-STAGE: March 22, 2017
    JOURNAL OPEN ACCESS

    Purpose: Previous research determined the relevance of masticatory performance with regard to nutritional status, cognitive functions, or stress management. In addition, the measurement of masticatory efficiency contributes to the evaluation of therapeutic successes within the stomatognathic system. However, the question remains unanswered as to what extent modern techniques are able to reproduce the subtle differences in masticatory efficiency within various patient groups. The purpose of this review is to provide an extensive summary of the evaluation of masticatory performance by means of a color-changeable chewing gum with regard to its clinical relevance and applicability.

    Study selection: A general overview describing the various methods available for this task has already been published. This review focuses in depth on the research findings available on the technique of measuring masticatory performance by means of color-changeable chewing gum. Described are the mechanism and the differentiability of the color change and methods to evaluate the color changes. Subsequently, research on masticatory performance is conducted with regard to patient age groups, the impact of general diseases and the effect of prosthetic and surgical treatment.

    Results: The studies indicate that color-changeable chewing gum is a valid and reliable method for the evaluation of masticatory function.

    Conclusion: Apart from other methods, in clinical practice this technique can enhance dental diagnostics as well as the assessment of therapy outcomes.

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Original Articles
  • Yoshizo Matsuka, Yoshiyuki Hagiwara, Katsushi Tamaki, Hisahiro Takeuch ...
    2017 Volume 61 Issue 1 Pages 20-33
    Published: 2017
    Released on J-STAGE: March 22, 2017
    JOURNAL OPEN ACCESS

    Purpose: The Japan Prosthodontic Society (JPS) has proposed a new diagnostic nomenclature system (DNS), based on pathogenesis and etiology, to facilitate and improve prosthodontic treatment. This system specifies patient disability and the causative factor (i.e. “B (disability) caused by A (causative factor)”). The purpose of this study was to examine the reliability and validity of this DNS.

    Study selection: The JPS Clinical Guideline Committee assessed mock patient charts and formulated disease names using the new DNS. Fifty validators, comprising prosthodontic specialists and dental residents, made diagnoses using the same patient charts. Reliability was evaluated as the consistency of the disease names among the validators, and validity was evaluated using the concordance rate of the disease names with the reference disease names.

    Results: Krippendorff's α was 0.378 among all validators, 0.370 among prosthodontic specialists, and 0.401 among dental hospital residents. Krippendorff's α for 10 validators (3 specialists and 7 residents) with higher concordance rates was 0.524. Two validators (1 specialist and 1 resident) with the highest concordance rates had a Krippendorff's α of 0.648. Common disease names had higher concordance rates, while uncommon disease names showed lower concordance rates. These rates did not show correlation with clinical experience of the validator or time taken to devise the disease name.

    Conclusions: High reliability was not found among all validators; however, validators with higher concordance rates showed better reliability. Furthermore, common disease names had higher concordance rates. These findings indicate that the new DNS for prosthodontic dentistry exhibits clinically acceptable reliability and validity.

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  • Panagiotis Tsirogiannis, Sophia Neophytou, Anika Reul, Guido Heydecke, ...
    2017 Volume 61 Issue 1 Pages 34-42
    Published: 2017
    Released on J-STAGE: March 22, 2017
    JOURNAL OPEN ACCESS

    Purpose: To develop a reliable and valid instrument for the comprehensive assessment of patients’ burdens during dental impression making, the Burdens in Dental Impression Making Questionnaire, BiDIM-Q.

    Materials: The item pool was generated in a convenience sample of 20 prosthodontic patients using semi-structured face-to-face interviews. The final instrument was tested in 145 consecutively recruited patients, and psychometric properties of the BiDIM-Q were determined. Four different impression materials were used according to the manufacturers’ instructions and indications: alginate, c-silicone, polyvinylsiloxane, and polyether.

    Results: The final BiDIM-Q consisting of 12 items showed sufficient reliability, indicated by Cronbach's alpha of .82 and an average inter-item correlation of .29. Validity was supported by Pearson correlation coefficients for the correlation between the instrument's total score with the patients’ overall satisfaction rating (r = .63), and by the correlation matrix for the correlations of the patients’ perceptions with the practitioners’ satisfaction ratings. Overall, patient perceived burdens were low with highest burdens observed when using polyether in partially dentate patients for pick-up impressions, while lowest burdens were reported when using c-silicone for impressions of edentulous jaws.

    Conclusion: The BiDIM-Q is a reliable and valid tool for assessing patient-based process-related quality of care in dentistry allowing a deeper insight into patients’ perspective during dental impression making.

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  • Miguel de Araújo Nobre, António Mano Azul, Evangelista Rocha, Paulo Ma ...
    2017 Volume 61 Issue 1 Pages 43-53
    Published: 2017
    Released on J-STAGE: March 22, 2017
    JOURNAL OPEN ACCESS

    Purpose: This study aimed to estimate the impact of risk factors for peri-implant pathology, to identify potentially modifiable factors, and to evaluate the accuracy of the risk algorithm, risk scores and risk stratification.

    Methods: This retrospective case–control study with 1275 patients (255 cases; 1020 controls) retrieved a model according to the predictors: history of Periodontitis, bacterial plaque, bleeding, bone level, lack of passive fit or non-optimal screw joint, metal-ceramic restoration, proximity to other implants/teeth, and smoking habits. Outcome measures were the attributable fraction; the positive and negative likelihood ratios at different disease cut-off points illustrated by the area under the curve statistic.

    Results: Six predictors may be modified or controlled directly by either the patient or the clinician, accounting for a reduction in up to 95% of the peri-implant pathology cases. The positive and negative likelihood ratios were 9.69 and 0.13, respectively; the area under the curve was 0.96; a risk score was developed, making the complex statistical model useful to clinicians.

    Conclusions: Based on the results, six predictors for the incidence of peri-implant pathology can be modified to significantly improve the outcome. It was possible to stratify patients per risk category according to the risk score, providing a tool for clinicians to support their decision-making process.

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  • Takamichi Ogino, Takayuki Ueda, Koichiro Ogami, Takashi Koike, Kaoru S ...
    2017 Volume 61 Issue 1 Pages 54-60
    Published: 2017
    Released on J-STAGE: March 22, 2017
    JOURNAL OPEN ACCESS

    Purpose: We examined how chewing rate and the extent of reactive hyperemia affect the blood flow in denture-supporting mucosa during chewing.

    Methods: The left palatal mucosa was loaded under conditions of simulated chewing or simulated clenching for 30 s, and the blood flow during loading was recorded. We compared the relative blood flow during loading under conditions that recreated different chewing rates by combining duration of chewing cycle (DCC) and occlusal time (OT): fast chewing group, typical chewing group, slow chewing group and clenching group. The relationship between relative blood flow during simulated chewing and the extent of reactive hyperemia was also analyzed.

    Results: When comparing the different chewing rate, the relative blood flow was highest in fast chewing rate, followed by typical chewing rate and slow chewing rate. Accordingly, we suggest that fast chewing increases the blood flow more than typical chewing or slow chewing. There was a significant correlation between the amount of blood flow during simulated chewing and the extent of reactive hyperemia.

    Conclusions: Within the limitations of this study, we concluded that slow chewing induced less blood flow than typical or fast chewing in denture-supporting mucosa and that people with less reactive hyperemia had less blood flow in denture-supporting mucosa during chewing.

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  • Caoimhin Mac Giolla Phadraig, June Nunn, Rachael Carroll, Mary McCarro ...
    2017 Volume 61 Issue 1 Pages 61-66
    Published: 2017
    Released on J-STAGE: March 22, 2017
    JOURNAL OPEN ACCESS

    Purpose: Older adults with intellectual disabilities (ID) are often edentulous. When total tooth loss occurs, they are very unlikely to wear complete removable dentures (CRDs) to restore oral function in Ireland. The reasons for this are unclear, though opinion holds that this is because dentists do not offer prosthodontic treatment to this group. In this study we ask edentulous older adults with ID why they do not wear dentures.

    Methods: Cross-sectional survey data from Wave 2 of the Intellectual Disability Supplement to The Irish Longitudinal Study on Ageing (IDS-TILDA) was examined to study reported denture wear among edentulous older adults with ID.

    Results: Out of 692 participants, 186 were edentulous (26.9%), of whom 57 (30.6%) wore CRDs and 129 (69.3%) did not. Twelve of this 129 had dentures but did not wear them. Of the 117 respondents who reported that they did not have dentures, 99 (valid % = 92.5%) did not want dentures, while only 8 did. No respondents in this study reported that they were denied denture therapy. Rather, they simply did not want dentures. Clinicians should understand that extra steps may be needed to ensure that consent is truly informed when patients opt for, or decline, complete denture therapy.

    Conclusion: While there is a high normative need for prosthodontic rehabilitation, expressed need is low. Extra steps may be necessary to ensure optimal outcomes for people with ID.

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  • Ippei Hamanaka, Hiroshi Shimizu, Yutaka Takahashi
    2017 Volume 61 Issue 1 Pages 67-72
    Published: 2017
    Released on J-STAGE: March 22, 2017
    JOURNAL OPEN ACCESS

    Purpose: This study evaluated the shear bond strength of a chairside autopolymerizing reline resin to injection-molded thermoplastic denture base resins.

    Methods: Four kinds of injection-molded thermoplastic resins (two polyamides, a polyethylene terephthalate copolymer and a polycarbonate) and PMMA, as a control, were tested. The eight types of surface treatment: ((1) no treatment, (2) air abrasion, (3) dichloromethane, (4) ethyl acetate, (5) 4-META/MMA-TBB resin, (6) air abrasion and 4-META/MMA-TBB resin, (7) tribochemical silica coating, and (8) tribochemical silica coating and 4-META/MMA-TBB resin) were applied to each specimen. The chairside autopolymerizing reline resins were bonded to disks of the injection-molded thermoplastic denture base resins. All of the specimens were immersed in water for 4 months and then thermocycled for 10,000 cycles in water between 5 and 55 °C. The shear bond strengths were determined.

    Results: The shear bond strengths of the two polyamides treated using air abrasion, dichloromethane and ethyl acetate and no treatment were exceedingly low. The greatest bond strength was recorded for the polyethylene terephthalate copolymer specimens treated with tribochemical silica coating and 4-META/MMA-TBB resin (22.5 MPa). The bond strengths of the other injection-molded thermoplastic denture base resins increased using 4-META/MMA-TBB resin.

    Conclusions: Tribochemical silica coating and 4-META/MMA-TBB resin were the most effective surface treatments among all denture base resins tested.

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  • Wataru Komada, Tasuku Inagaki, Yoji Ueda, Satoshi Omori, Keiichi Hosak ...
    2017 Volume 61 Issue 1 Pages 73-80
    Published: 2017
    Released on J-STAGE: March 22, 2017
    JOURNAL OPEN ACCESS

    Purpose: The purpose of this study was to evaluate the influence of water immersion on the mechanical properties of three kinds of glass fiber posts and the fracture resistance of structures using resin composites with glass fiber posts.

    Methods: Each post was divided into three groups; a control group and two water immersion groups (30 and 90 days). Flexural strength was determined by three-point bending test. Each structure was divided into two groups; a control group and a water immersion group for 30 days. The fracture strength of structures was determined by a static loading test.

    Results: In the flexural strength, two kinds of post in water immersion groups showed lower values than control groups. In the fracture strength, two kinds of structures in water immersion group showed lower values than control groups.

    Conclusion: The prefabricated glass fiber posts and structures using resin composites with glass fiber posts were affected by water immersion.

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Technical Procedure
Case Report
  • Kazuo Okura, Shuji Shigemoto, Yoshitaka Suzuki, Naoto Noguchi, Katsuhi ...
    2017 Volume 61 Issue 1 Pages 87-95
    Published: 2017
    Released on J-STAGE: March 22, 2017
    JOURNAL OPEN ACCESS

    Patient: Observation of attrition patterns suggests that mandibular movement in sleep bruxism (SB) may be associated with current tooth attrition. The aim of this study was to confirm this phenomenon by investigating mandibular movement and masseter muscle activity. The subject was a healthy 21-year-old Japanese male. We recorded biological signals including mandibular movement and masseter electromyograms (EMGs) with a polysomnograph. Based on the EMG using Okura's criteria, SB events were classified into clenching, grinding and mixed types according to mandibular movement criteria. The close-open mandibular movement cycles (CO-cycles) during grinding and mixed type events were selected based on mandibular movement trajectories.

    Discussion: Fifty-eight CO-cycles were selected in seven grinding and three mixed types. We found that SB mandibular movements associated with current tooth attrition. Excessive lateral movements (ELM) beyond the canine edge-to-edge position were observed in the closing (10.3%) and opening (13.8%) phases of the CO-cycle. Total masseter muscle activity was significantly higher during voluntary grinding (VGR) than during CO-cycle including ELM (working side: P = 0.036, balancing side: P = 0.025). However, in the middle and late parts of the opening phase, working side masseter muscle activity was significantly higher during CO-cycle including ELM than during VGR (P = 0.012). In the early part of the closing phase, balancing side masseter muscle activity was significantly higher during CO-cycle including ELM than during VGR (P = 0.017).

    Conclusion: These findings suggest that excessive forceful grinding during ongoing SB events may have caused canine attrition in this patient.

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