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The aim of this study was to investigate the effects of swallowing exercises on oral function in independent elderly patients visiting the Department of Prosthodontics at Tokyo Dental College Chiba Hospital. Twenty-nine patients aged over 65 years (15 men and 14 women; mean age, 75.0 years) in whom treatment was completed at this college were enrolled in the study. The patients were instructed on how to perform swallowing exercises monthly (including at baseline) for the first 2 months from the start of the study and asked to perform those exercises at least once daily. At the beginning and end of the study (a 3-month study period), the Repetitive Saliva Swallowing Test was conducted and occlusal force, oral diadochokinesis, unstimulated whole saliva flow rate, stimulated whole saliva flow rate, salivary pH at rest, and salivary buffering capacity measured to determine the effects of the exercises on oral function. Analyses demonstrated significant increases in diadochokinesis rate (/ta/ and /ka/) and unstimulated whole saliva flow rate (p<0.05), suggesting that the swallowing exercises promote the maintenance and improvement of oral function in the independent elderly.

Ce-TZP/Al(2)O(3) nanocomposite (NANOZR) has not only higher strength, but also higher fracture toughness than conventional Y-TZP, indicating its potential for use in dental implants. Surface treatment to obtain osseointegration, however, may alter its surface topography, thus affecting the cyclic fatigue strength that plays such an important role in the durability of this material. The aim of this study was to evaluate the influence of surface treatment on cyclic fatigue strength in NANOZR as compared with grit-blasted and acid-etched Y-TZP (125BE Y-TZP). Bi-axial flexure strength was measured in both static and cyclic fatigue tests, as recommended by ISO 6872. The cyclic fatigue test was performed by the staircase method in distilled water at 37°C, with a load of 10(6) cycles and 10 Hz. Bi-axial flexure strength of NANOZR was 1111-1237 MPa and 667-881 MPa in the static and cyclic fatigue tests, respectively. The bi-axial flexure strength of NANOZR under all conditions was greater than that of 125BE Y-TZP in the static and cyclic fatigue tests. The cyclic fatigue strength of NANOZR was more than twice that of Y-TZP as specified in ISO 13356 for surgical implants (320 MPa), indicating the promise of this material for use in dental implants.

Objectives To investigate the in vitro diagnostic accuracy of low‐dose cone‐beam computed tomography (LD‐CBCT) for the detection, classification, and measurement of peri‐implant bone lesions. Material and methods Titanium dental implants with all‐ceramic single crowns (n = 24) were inserted into bovine bone. At twelve implants, four types of peri‐implant bone lesions were created. Radiographic imaging was performed using three techniques: LD‐CBCT, high‐definition CBCT (HD‐CBCT), and intraoral radiography (IR). The datasets were presented twice to four observers in a random order. Diagnostic accuracy was measured by calculating sensitivity and specificity, and analyzed using the McNemar's test at a significance level of 0.05. Absolute agreement between the defect sizes was assessed by means of intraclass correlation coefficients (ICC). Results For all three techniques, diagnostic accuracy and reliability for the detection of defects were almost perfect. The following order was found for classification of the different defect types (sensitivity/specificity): HD‐CBCT (0.96/0.99) > LD‐CBCT (0.93/0.98) > IR (0.71/0.95). No significant difference was found between the two CBCT techniques. Their performance was superior to that of IR. With regard to absolute agreement of defect size, LD‐CBCT agreement with HD‐CBCT (ICC, 95% confidence interval) was slight for defect depth (0.342, 0.181–0.625) and substantial for defect width (0.911, 0.775–0.963). Conclusion Intraoral radiography is useful for detecting peri‐implant bone lesions. LD‐CBCT provides additional information regarding the geometry of defects. The even higher diagnostic accuracy of the HD‐CBCT protocol tested needs to be carefully weighed against its radiation dose, which is 14 times higher than that of LD‐CBCT.