An evaluation of antagonist enamel wear opposing full-coverage zirconia crowns versus other ceramics full-coverage crowns and natural enamel - An umbrella review.

AIM: The aim of this umbrella review was to systematically review the systematic reviews on antagonist enamel wear opposing zirconia crowns compared to other ceramics and natural enamel. SETTINGS AND DESIGN: This was an umbrella review following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. MATERIALS AND METHODS: An electronic search of PubMed, Cochrane Central, EBSCOhost, and Google Scholar search engines for articles published from January 1, 2013, to January 1, 2023, was conducted using keywords "enamel wear," "zirconia," "feldspathic," "dental ceramics," and "Y-TZP" to identify systematic reviews on antagonist enamel wear opposing zirconia crowns compared to other ceramics and natural enamel. STATISTICAL ANALYSIS USED: Qualitative analysis. RESULTS: A total of 86 articles were obtained through electronic search, of which four articles were selected after abstract screening that met the inclusion criteria for evaluating antagonist enamel wear. As compared to feldspathic groups, zirconia had substantially less antagonist wear, while surface polishing exhibited less enamel wear than glazing. Because of the heterogeneity in study design, measurement methods, and outcome variables, a meta-analysis was not possible. CONCLUSIONS: Over time, the opposing enamel wear caused by polished monolithic zirconia will be either equal to or less than that of natural enamel wear. Polished monolithic zirconia also maintains lower values of enamel wear compared to metal ceramics, feldspathic porcelains, and lithium disilicate.

Assessment of dimensional stability of novel VPES impression material at different time intervals with standard disinfectants.

BACKGROUND: Vinyl polyether silicone (VPES) is a novel impression biomaterial made of a combination of vinyl polysiloxane (VPS) and polyether (PE). Thus, it is significant to assess its properties and behaviour under varied disinfectant test conditions. This study aimed to assess the dimensional stability of novel VPES impression material after immersion in standard disinfectants for different time intervals. METHODS: Elastomeric impression material used -medium body regular set (Monophase) [Exa'lence GC America]. A total of 84 Specimens were fabricated using stainless steel die and ring (ADA specification 19). These samples were distributed into a control group (n=12) and a test group (n=72). The test group was divided into 3 groups, based on the type of disinfectant used - Group-A- 2% Glutaraldehyde, Group-B- 0. 5% Sodium hypochlorite and Group-C- 2% Chlorhexidine each test group was further divided into 2 subgroups (n=12/subgroup) based on time intervals for which each sample was immersed in the disinfectants - subgroup-1- 10 mins and Subgroup 2- 30 mins. After the impression material was set, it was removed from the ring and then it was washed in water for 15 seconds. Control group measurements were made immediately on a stereomicroscope and other samples were immersed in the three disinfection solutions for 10 mins and 30 mins to check the dimensional stability by measuring the distance between the lines generated by the stainless steel die on the samples using a stereomicroscope at x40 magnification. RESULTS: The distance measured in the control group was 4397.2078 µm and 4396.1571 µm; for the test group Group-A- 2% Glutaraldehyde was 4396.4075 µm and 4394.5992 µm; Group-B- 0. 5% Sodium hypochlorite was 4394.5453 µm and 4389.4711 µm Group-C- 2% Chlorhexidine was 4395.2953 µm and 4387.1703 µm respectively for 10 mins and 30 mins. Percentage dimensional change was in the range of 0.02 - 0.25 for all the groups for 10 mins and 30 mins. CONCLUSIONS: 2 % Glutaraldehyde is the most suitable disinfectant for VPES elastomeric impression material in terms of dimensional stability and shows minimum dimensional changes as compared to that of 2% Chlorhexidine and 0.5% Sodium hypochlorite.

An Analysis of Relative Gait Impairment in Commonly Diagnosed Pediatric Conditions.

BACKGROUND: Gait indices were developed to represent the magnitude of impairment extracted from a gait analysis with a single value. The Gillette Gait Index (GGI), and the Gait Deviation Index (GDI) are 2 widely used indices that represent gait impairment differently based on their statistical properties. Our purpose was to (1) report on the results of gait analysis for a broad spectrum of pediatric conditions using the GGI and GDI, and (2) identify the parameters that dominate impairment. METHODS: A total of 1439 children with 13 different diagnoses with a complete, baseline gait analysis were identified. The GGI and its 16 parameters were calculated in all cases, and the GDI was calculated from a smaller subset. T tests, and z-scores were used to compare each of these values to typically developing children for each diagnosis. A separate linear regression controlling for age, sex, and use of an orthosis, or assistive device was performed for the GGI. RESULTS: In our series, there were 71 typically developing children with a GGI of 31. We qualify relative gait impairment as severe, mild, or moderate as based on the GGI, and propose that values <100 represent mild, 100 to 200 represent moderate, and >200 represents severe impairment. On the basis of strong correlation between the GGI and GDI, we suggest that GDI values >80 represent mild, and values <70 represent severe impairment. T tests and z-scores demonstrated that both the number and magnitude of abnormal parameters increase the GGI. These tests also identified the most clinically relevant parameters contributing to functional impairment for each diagnosis. Multivariate linear regression showed that all diagnoses except flatfoot and scoliosis demonstrated statistically significant differences in GGI scores. CONCLUSIONS: This is the first study to apply these gait indices to a large population of diverse pediatric conditions. We propose GGI and GDI values to qualify gait impairment among these conditions as severe, moderate, or mild. Furthermore, impairment in gait reflects both the number and magnitude of abnormal parameters within each condition. LEVEL OF EVIDENCE: Level III-retrospective comparative study.