Objective: Oral rehabilitation success is enhanced by an accurate and reproducible final impression. The purpose of this study is to evaluate the dimensional changes of a polyether and addition silicone subjected to disinfection and/or sterilization after a long storage period. Material and methods: Ninety samples were obtained from polyether ImpregumTM PentaTM (3M ESPETM, Seefeld, Germany) and 90 of addition silicone ImprintTM 4 PentaTM Putty (3M ESPETM, Seefeld, Germany) according to ISO 4823:2000. The samples of each material were split to form three groups with 30 samples each: a control group, a hypochlorite group (disinfection) and an autoclave group (sterilization). Samples were stored in the Portuguese Institute for Quality for six months at 23 °C. Samples were measured by laser interferometry, according to the Michelson technique before calculating dimensional stability according ISO 4823:2000. A statistical analysis via a three-way mixed ANOVA was performed. Results: Significant shrinkage of ImpregumTM PentaTM was 0.77 ± 0.17% in the control group, 0.42 ± 0.19% in the hypochlorite group and 0.52 ± 0.28% in the autoclave group. For ImprintTM 4 PentaTM Putty, the control group had a shrinkage of 0.42 ± 0.12%, the hypochlorite group 0.36 ± 0.09% and the autoclave group 0.59 ± 0.13%. Conclusions: The long-term storage of samples subjected to disinfection with 5.25% hypochlorite or autoclave sterilization can be used in a clinical setting as the dimensional changes are below the maximum permitted by the ISO 4823:2000, since there are no clinically significant changes in the dimension of the samples during the storage period.
Oral rehabilitation success depends upon the accuracy and dimensional stability of the impressions. The purpose of this study is to evaluate the dimensional changes of a first impression type VPS (Vinyl Polysiloxane) (Imprint™ 4 Preliminary Penta™ Super Quick, 3M ESPE™, St Paul, MN, USA). 10 samples were obtained from this silicone with an automatic mixing machine (Pentamix 2, 3M ESPE™, Seefeld, Germany) according to International Organization for Standardization (ISO) 4823:2000 and stored in the IPQ (Portuguese Institute for Quality) for one week. The measurements were performed by laser interferometry, according to the Michelson technique. The dimensional stability was calculated according to the formula specified in ISO (International Organization for Standardization) 4823:2000. A statistical analysis via a one-way repeated measures ANOVA was performed. The material shrinkage was 0.29 ± 0.15% after setting, 0.32 ± 0.21% at 24 h and 0.30 ± 0.23% after 1 week. No significant shrinkage of the silicone under investigation was found over time. This material can be stored for a week without the risk of clinically significant dimensional changes.
The purpose of this study was to evaluate the color changes of feldspathic ceramics CEREC Blocs (Dentsply Sirona, Milford, DE, USA) when cemented with different luting agents, while varying the ceramic thickness. Seventy ceramic discs of feldspathic ceramic (A2 shade) were obtained with 0.5 and 0.8 mm thicknesses. Seventy composite discs (A3 shade) 1 mm in thickness were used as substrates. After being polished and conditioned, the ceramic and composite discs were cemented with different resin cements and a flowable composite: Variolink® Esthetic Light, Neutral and Warm (Ivoclar Vivadent, Schaan, Liechtenstein); RelyXTM Veneer B0.5, Translucent and A3 Opaque/yellow shades (3M Oral Care, St. Paul, MN, USA); G-aenial® Universal Flow A2 (GC Europe, Leuven, Belgium). Color difference (ΔE) was determined using a spectrophotometer. A two-way ANOVA and multiple comparisons were performed using the Bonferroni method with a 95% confidence interval. Variolink® Neutral showed the highest ΔE (15.12 ± 0.71) and RelyXTM Veneer A3 the lowest value (1.59 ± 0.33). There are no statistically significant differences between the two ceramic thicknesses for Variolink® Light (p = 0.230) and RelyXTM Veneer B0.5 (p = 0.318) cements. The feldspathic ceramic final color is influenced by the cement used and the ceramic thickness. The use of different cements in a thin ceramic has a clinically significant impact on the final esthetic result.
Objective The purpose of this study is to evaluate the color changes of lithium disilicate ceramics when cemented with different brands of cement by varying the thickness of the ceramic. Materials and Methods Forty ceramic discs, shade A2, were fabricated with 0.5 and 0.8 mm thickness. Forty composite resin discs, shade A3, were also produced. The ceramic samples were cemented to the composite resin discs, with two colors of resin cement, Neutral and Warm. A spectrophotometer evaluation was made. Translucency and color change analysis was performed by calculating the ΔE. A two‐way analysis of variance test and multiple comparisons were performed using the Bonferroni method with a 95% confidence interval. Results There are statistically significant differences between the two ceramic thicknesses with different brands of cement (p < .001). In addition, using the translucency analysis it was found that there are statistically significant differences between the two ceramic thicknesses in both types of cement (p < .001). Conclusions The use of different cementation materials on lithium disilicate ceramics appears to have little visible influence at the clinical level. Different ceramic thicknesses have a clinically visible influence on the final restoration color.
In vitro studies evaluating the cytotoxic potential of substances released from dental adhesives are lacking. The purpose of this study was to compare the cytotoxicity of the extracts of dental adhesives Scotchbond Universal and Optibond Solo Plus, and an adhesive in the experimental phase: T1. 3T3 mouse fibroblast cells and MG-63 osteoblast-like cells from human osteosarcoma were exposed for 24 h to serial extract dilutions. Cytotoxicity was determined using an MTT assay. For both cell lines, the cytotoxicity order obtained, of the unfiltered adhesive extracts, was T1 (less cytotoxic) < Optibond Solo Plus < Scotchbond Universal (most cytotoxic).
View related articlesView Crossmark data increase [1,2]. However, there is still a lack of information for the Portuguese population for this issue. This exploratory study aimed to evaluate the relationship between patient perception of OHRQoL and the severity of dental malocclusion in a Portuguese sample. Materials and methods: This work was approved by the Egas Moniz Ethics Committee. This cross-sectional observational study involved patients that sought orthodontic treatment between January and April 2019, at the Orthodontic Care Consultation of Egas Moniz Dental Clinic (Monte de Caparica -Almada, Portugal). Exclusion criteria were patients with severe diseases, craniofacial abnormalities, cognitive deficits, caries, periodontal diseases, and previous orthodontic treatment history. A total of 19 patients were enrolled in the study. OHRQoL was assessed by application of the Oral Health Impact Profile -Portuguese validated version [3] and dental malocclusion through the Index of Complexity, Outcome and Need (ICON) [4]. Based on the ICON score, patients were categorised as: in need of treatment (ICON > 43) or not (ICON 43). Resulting data were submitted to descriptive and inferential statistical analysis. Results: The sample included 7 (37%) males and 12 (63%) females, with a mean age of 27.9 years. Overall OHIP-14 score ranged from 0 to 49 and ICON score from 13 to 75 (9 (47.4%) subjects with ICON > 43 and 10 (52.6%) with ICON 43). Total OHIP-14 score and all seven median domain scores were not found to be significantly different (p ¼ .113 to p ¼ .968), when comparing both groups. Discussion and conclusions: OHRQoL was not found to be significantly different when considering the severity of dental malocclusion. Overall, results highlight a difference between patients' self-perception of clinical condition impact in OHRQoL when compared to a clinical expertise judgement.
View related articlesView Crossmark data used in this study positioned the temporomandibular joint in a centric relation position. Kinematic data were collected using a 3D motion capture, consisting five high speed cameras system, for body horizontal sway (shoulders, anterior and posterior superior iliac spine) and vertical sway (spine). This research was approved by the ethics committee of the Faculdade de Motricidade Humana for use of human research (6/2016). Results: The use of occlusal splints did not influence the body sway during gait and running since no differences were found in the mean values for both horizontal and vertical body sway, for all the test conditions Discussion and conclusions: Dental occlusion, achieved through the use of occlusal splints, that change the temporomandibular joint into a centric relation position, appears to have no effect on body horizontal and vertical sway, for gait and running in healthy male subjects. High inter-subject variability in the kinematic parameters was found, mainly during gait. Due to this, intra-subject variability should be considered in future studies in order to understand the occlusal splints influence among subjects.
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