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The influence of monomer content on the viscoelasticity, water sorption and solubility of experimental fluorinated soft lining materials was investigated. Changes in the viscoelastic properties of the materials were also examined after thermal cycling. Four fluorinated soft lining materials containing different amounts of methoxy diethylene glycol methacrylate (MDGMA) and tridecafluorooctyl methacrylate (13FMA) were prepared. The viscoelastic displacement for specimens containing 13FMA was found to be less than that without 13FMA (p<0.05), and the values tended to decrease with increasing 13FMA content. Reduction of the MDGMA content and addition of 13FMA caused a decrease of water sorption and solubility (p<0.05). Thermal cycling was found to affect the viscoelastic deformation of the specimens without 13FMA and those specimens with relatively large amounts of 13FMA. [ABSTRACT FROM AUTHOR]

Background Demand for complete denture treatment is expected to rise over several decades. However, to date, no questionnaire on complete dentures, as evaluated by edentulous patients, has been shown to be reliable and valid. This study sought to assess the reliability and validity of Patient's Denture Assessment (PDA), which provides a multidimensional evaluation of dentures among edentulous patients. Methods Patients, who had new complete dentures fabricated at the University Hospital of Dentistry, Tokyo Medical and Dental University through 2009 to 2010, were enrolled. The reliability of the PDA was determined by examining internal consistency and test-retest reliability. Internal consistency for all of the question items and the six subscales was measured using Cronbach's α and average inter-item correlation coefficients among 93 participants. For 33 of these participants, test-retest reliability was determined at a 2 month-interval using the interclass correlation coefficients (ICCs) and 95% confidence interval for the summary scores and the six subscale scores. The PDA was validated in 93 participants by examining the difference in the summary score and the six subscale scores of the PDA before and after replacement with new dentures by the paired t-test. Ability to detect change was also tested in 93 patients using effect size.Results The Cronbach's α for the PDA ranged from 0.56 to 0.93. The average inter-item correlation coefficients ranged from 0.28 to 0.83. ICCs for the PDA ranged from 0.37 to 0.83. The paired t-test showed a significant difference between the summary score and the six subscale scores before and after replacement with new dentures (p < 0.05) and the effect size was 0.97. Conclusions The PDA demonstrated good reliability by assessing internal consistency and test-retest reliability. In addition, the PDA demonstrated good validity by assessing discriminant validity. Thus, the PDA could help dentists obtain a detailed understanding of the patients' perceptions in using their dentures. [ABSTRACT FROM AUTHOR]

Vertical misfit of implant-abutment interface can affect the success of implant treatment; however, currently available modalities have limitations to detect these gaps. This study aimed to evaluate implant-abutment gaps in vitro using optical coherence tomography (OCT). Vertical misfit gaps sized 50,100,150, or 200 μm were created between external hexagonal implants and titanium abutments (Nobel Biocare, Göteborg, Sweden). A porcine gingival tissue slice, 0.5, 1.0, 1.5, or 2.0 mm in thickness, was placed on each implant-abutment interface. The gaps were evaluated by swept-source OCT at a center wavelength of 1330 nm (Panasonic Healthcare, Ehime, Japan) with beam angles of 90, 75 and 60 deg to the implant long-axis. The results suggested that while the measurements were precise, gap size and gingival thickness affected the sensitivity of detection. Gaps sized 100 μm and above could be detected with good accuracy under 0.5- or 1.0-mm-thick gingiva (GN). Around 70% of gaps sized 150 μm and above could be detected under 1.5-mm-thick GN. On the other hand, 80% of gaps under 2.0-mm-thick GN were not detected due to attenuation of near-infrared light through the soft tissue. OCT appeared as an effective tool for evaluating the misfit of implant-abutment under thin layers of soft tissu [ABSTRACT FROM AUTHOR]

Aim: This cross-sectional study had two aims: to assess the prevalence of oral frailty (OF), according to the Oral Frailty 5-Item Checklist (OF-5), among community-dwelling older adults; and to examine the associations among oral frailty, dietary variety, social engagement, and physical frailty. Methods: We pooled data from two population-based studies (the Otassha Study and the Itabashi Longitudinal Study on Aging). With the OF-5, OF is characterized by the presence of two or more of the following: (i) fewer teeth, (ii) difficulty in chewing, (iii) difficulty in swallowing, (iv) dry mouth, and (v) low articulatory oral motor skills. We calculated the OF prevalence for each sex. We assessed dietary variety, social engagement, and physical frailty. Generalized structural equation modeling was employed to investigate the associations among oral frailty, low dietary variety (dietary variety score =3), social isolation (Lubben Social Network Scale score <12), and physical frailty (Japanese version of the Cardiovascular Health Study score =3). Results: A total of 1206 individuals (626 women and 580 men) with a mean age of 74.7 years were included. The prevalence of OF was 36.7%, and it increased with age; however, there was no significant sex difference. OF was significantly indirectly associated with physical frailty via low dietary variety (odds ratio, 1.43; 95% confidence interval, 1.04-1.97) and social isolation (odds ratio, 1.42; 95% confidence interval, 1.04-1.94). Conclusions: Two of five community-dwelling older adults exhibited OF. Low dietary variety and social isolation are potential underlying mechanisms through which OF is indirectly associated with physical frailty. [ABSTRACT FROM AUTHOR]

Objectives: To investigate the relationship between mandibular ridge form, stability and retention of mandibular complete denture, accuracy of jaw relation recording, patients' perception of chewing ability, satisfaction with dentures and oral health-related quality of life (OHRQoL) in complete denture wearers. Methods: A total of 183 edentulous patients, who visited the Dental Hospital of Tokyo Medical and Dental University for new complete dentures, were recruited. Oral examination was performed. Cawood and Howell's method was used to grade the mandibular ridge form. The stability and retention of the mandibular complete denture were assessed using Kapur method. Accuracy of jaw relation recording was evaluated using a newly developed jaw relation index. Patients' perception of chewing ability was rated using a food intake questionnaire. Patients' satisfaction with complete dentures was assessed on a 100-mm visual analogue scale. OHRQoL was measured using the Japanese version of the Oral Health Impact Profile for edentulous subjects. A structural equation model was constructed based on the hypothesis that oral condition and denture quality would be related to chewing ability, satisfaction and OHRQoL. Results: Significant relationships were found between mandibular ridge form, stability of mandibular complete denture, accuracy of jaw relation recording, perceived chewing ability, satisfaction and OHRQoL. Various fit indices were within acceptable limits. Conclusions: Oral condition and denture quality were related to patients' perception of chewing ability, satisfaction with dentures and OHRQoL in complete denture wearers. Clinical significance: A favourable oral condition and denture quality are important for successful complete denture therapy. [ABSTRACT FROM AUTHOR]

Objectives: To compare the effect of conventional complete dentures (CD) fabricated using two different impression methods on patient-reported outcomes in a randomized controlled trial (RCT). Methods: A cross-over RCT was performed with edentulous patients, required maxillomandibular CDs. Mandibular CDs were fabricated using two different methods. The conventional method used a custom tray border moulded with impression compound and a silicone. The simplified used a stock tray and an alginate. Participants were randomly divided into two groups. The C-S group had the conventional method used first, followed by the simplified. The S-C group was in the reverse order. Adjustment was performed four times. A wash out period was set for 1 month. The primary outcome was general patient satisfaction, measured using visual analogue scales, and the secondary outcome was oral health-related quality of life, measured using the Japanese version of the Oral Health Impact Profile for edentulous (OHIP-EDENT-J) questionnaire scores. Results: Twenty-four participants completed the trial. With regard to general patient satisfaction, the conventional method was significantly more acceptable than the simplified. No significant differences were observed between the two methods in the OHIP-EDENT-J scores. Conclusions: This study showed CDs fabricated with a conventional method were significantly more highly rated for general patient satisfaction than a simplified. Clinical significance: CDs, fabricated with the conventional method that included a preliminary impression made using alginate in a stock tray and subsequently a final impression made using silicone in a border moulded custom tray resulted in higher general patient satisfaction. [ABSTRACT FROM AUTHOR]

Recently, computer-aided design/computer-aided manufacturing (CAD/CAM) technology has been applied to the field of removable complete denture prosthodontics. We developed a system for fabricating complete dentures applying CAD/CAM technology. In this system, artificial teeth were bonded to the recesses of a milled denture base. However, the offset values needed for the recesses are not known. The purpose of the present study was to evaluate the accuracy of bonded artificial teeth positions in 0.00 (control), 0.10, 0.15, 0.20, and 0.25 mm offset recess groups. Four types of artificial teeth, upper left central incisor (UL1), upper left canine (UL3), upper left first premolar (UL4), and upper left first molar (UL6), were used. Each type of artificial tooth was arranged at regular intervals on the denture base model with the CAD software. These data were defined as the master data. The artificial teeth parts were subtracted from the denture base model by Boolean logic operations in order to make recesses, and the recesses were then offset in five values. Based on these denture base data, prepolymerized resin blocks were milled (n=3). After bonding artificial teeth on the milled denture base model, a cone beam computed tomography (CBCT) scan was performed to obtain scanned data. Deviations between the master data and the scanned data were calculated. Based on the results, the optimal offset values were found to be 0.15-0.25 mm for UL1, 0.15 and 0.25 mm for UL3, 0.25 mm for UL4, and 0.10-0.25 mm for UL6. [ABSTRACT FROM AUTHOR]

Several reports have recently been published regarding dysphagia in very elderly patients, and centenarian dysphagia patients have become more common in Japan. The aim of this study was to assess the prognosis of dysphagia in very elderly patients. Participants were 24 centenarian dysphagia patients. For each patient, we collected information on age, care level, past medical history, and changes in oral intake according to the Functional Oral Intake Scale (FOIS). Patients were divided into two groups based on the mode of food intake at the time of transfer or discharge: the per oral-only group (the PO-only group, i.e., oral intake alone) and the tube feeding-dependent group (the TF-dependent group, i.e., combination of oral intake and tube feeding, or tube feeding alone). In both groups, the FOIS score decreased significantly from pre-hospitalization to the time of transfer or discharge (p = 0.006 for both). The FOIS score at initial assessment was higher in the PO-only group with the TF-dependent group (p = 0.0004). Furthermore, the frequency of a FOIS score of 4 at initial assessment was significantly higher in the PO-only group, and the frequency of a FOIS score of 1 was significantly higher in the TF-dependent group (p = 0.0006). These findings collectively suggest that oral intake can be recovered if the FOIS score is ≥4 at initial assessment, is difficult if the score is 1, and may be possible with a FOIS score of 2. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the accuracy of implant placement with mucosa-supported surgical guides in edentulous mandibles and to determine the factors affecting accuracy. Implant placement was simulated on the preoperative CT image and mucosa-supported surgical guides were fabricated for six edentulous mandible models and 15 patients with edentulous mandibles, using CAD/CAM technology. Deviations of the actual implant position from the planned position were calculated by comparing the planned image and the postoperative image. Based on the results, it was concluded that mucosa-supported surgical guides have high accuracy and that bone density and mucosal thickness could affect accuracy. [ABSTRACT FROM AUTHOR]