RESUMO
The goal of this study was to evaluate the pH and the release of calcium from four calcium-silicate-based cements. METHODS: Four materials were tested (ProClinic MTA; Angelus MTA; ProRoot MTA; Biodentine). The palatal canal root of acrylic upper molars was filled with each cement. Afterwards, they were set in phosphate-buffered saline. Measurements were taken by atomic adsorption spectroscopy (AAS) at 3, 24, 72, 168, 336, 672, and 1008 h. The pH was measured at the same timepoints. Kruskal-Wallis tests were carried out in each period, as the Kolmogorov-Smirnov and Shapiro-Wilk tests showed no parametric results. RESULTS: Significant differences (p < 0.05) in calcium release were found at the 3-, 24-, and 72-hour evaluations. All of the analyzed groups presented a release of calcium ions up to 168 h, and the general tendency was to increase up to 672 h, with a maximum release of 25.45 mg/g in the ProRoot group. We could only observe significant differences (p < 0.05) in pH value over 168 h between the Biodentine (7.93) and Angelus MTA (7.31) groups. CONCLUSIONS: There were significant differences (p < 0.05) in calcium release. Nevertheless, no significant differences (p > 0.05) in the pH values were found at the studied timepoints, except for the values at 168 h.
RESUMO
PURPOSE: Evaluating the distortion probability in impressions of completely dentate arches when different impression materials are used in relation to operator experience. MATERIAL AND METHODS: Twenty-eight students (group A) and 7 dentists (group B) performed 3 maxillary impressions on 28 students (participants), each using vinyl siloxane ether (VSE), polyether (PE), and irreversible hydrocolloid (IHC). Gypsum master casts were fabricated and subsequently digitized. Intraoral scans were taken as a control. Differences between master casts and intraoral scans were visualized by heatmaps and planar deviations were investigated. If planar deviations of >120 µm were found, the impression was rated as "distorted." An additional superimposition using the casts from VSE or PE was performed to confirm the presence of distortions. The relative number of surfaces with distortions in each impression was calculated. The procedure was repeated for a distortion threshold of 500 µm. The statistical analyses included measures ANOVA and post-hoc tests (a < 0.05). RESULTS: When 120 µm was considered as the threshold for distortions, IHC impressions showed higher distortion probability than PE impressions in group A (P = 0.003) and group B (P < 0.0001). In group B only, PE showed a lower distortion probability than VSE (P = 0.02). There was no difference between the study groups (P = 0.42). Considering 500 µm as a threshold for distortions, there was no difference between impression materials (P = 0.17) or study groups (P = 0.53). CONCLUSION: There were no statistic significant differences in relation to operator experience. Different impression materials had a significant impact on distortion probability. Polyether impressions showed the lowest distortion probability. Int J Prosthodont. 10.11607/ijp.8555.
RESUMO
According to the World Health Organization (WHO), the estimated number of older adults is around 962 million and is projected to increase to 2.1 billion by 2050. The oral frailty concept is associated with gradual oral function loss in relation to aging. There is a need to emphasize the improvement of oral function based on an evaluation of masticatory performance in patients with various oral conditions or systemic diseases and especially in the frail elderly. The present narrative review presents an overview of the current state of the assessment and improvement of masticatory performance in frail older people. To fully encompass oral frailty, oro-facial hypofunction, or oro-facial fitness, dental Patient Reported Outcomes (dPROs) should be included; nevertheless, there are limited evidence-based rehabilitation approaches. The concept of oral frailty, oro-facial hypofunction, or oro-facial fitness should involve dental Patient Reported Outcomes (dPROs), and in this sense, there are only a few evidence-based rehabilitation procedures to improve oro-facial hypofunction besides prosthodontics. It must be considered that reduced neuroplastic capacity in old individuals might preclude a positive outcome of these strategies that might need to be accompanied by functional training and nutritional counseling.
RESUMO
OBJECTIVE: To assess the marginal and bacterial microleakage in zirconia and CAD-CAM or cast Co-Cr implant abutments. METHODS: Sixty-four conical connection implants with their respective abutments were divided into four groups (Co-Cr (milled, laser-sintered, and cast) and Zirconia (milled)). All specimens were subjected to a chewing simulation and thermocycling. After aging process, specimens were submerged in a 0.2% methylene blue solution with Porphyromonas gingivalis (P.g) for 48 h. The marginal microleakage was measured using a 40× optical microscopy at the internal part of the implant, and when positive microleakage was observed, a DNA isolation with a polymerase chain reaction (PCR) test was used. The microbiological assessment was based on colony forming units (CFUs). RESULTS: Thirty (47%) implant-abutments presented microleakage and the PCR was performed on those specimens (1 Zirconia, 1 Co-Cr milled, 14 Co-Cr laser-sintered and 14 cast). Seven specimens (1 Co-Cr laser-sintered and six cast) presented values below the PCR detection limit (< 100 CFUs). The lowest CFUs count occurred in the Co-Cr milled group (5.17E+02 CFUs/ml) followed by zirconia (7.70E+03 CFUs/ml). The Co-Cr cast (9.39E+03 CFUs/ml) and laser-sintered (2.4E+05 CFUs/ml) groups had higher bacterial count. The CFU count comparison performed between Co-Cr cast and laser-sintered resulted in a statistically significant differences in favor of Co-CrCL (p < .05). CONCLUSIONS: The abutment material and fabrication technique affected the implant-abutment microleakage. Although the CAD-CAM abutments presented favorable results, all tested groups presented microleakage.