Clinical study of the color stability of veneering ceramics for zirconia frameworks

PURPOSE: The purpose of this study was to compare 3 veneering ceramics for zirconia frameworks regarding color stability and predictability of the esthetic result. Materials AND METHODS: Six patients with 1 maxillary central incisor to be restored were enrolled in the study. The contralateral incisor had to be nonrestored and vital to serve as a reference tooth. For each patient, 4 single crowns with zirconia frameworks were fabricated. Three veneering ceramics were assessed and masked to eliminate bias. Choice of the veneering ceramics was done at random. The veneering was performed by 4 dental technicians. Three veneering ceramics were compared: ceramic A (Initial, GC), ceramic B (Triceram, Esprident), and ceramic C (Cercon Ceram S, DeguDent). The color of the crowns and reference teeth was captured using spectrophotometric analysis (SpectroShade, MHT), and the color difference (deltaE) was calculated (objective method). In addition, the crowns and reference teeth were compared subjectively by 11 observers blind to the ceramic used for veneering. Statistical analysis was performed with analysis of variance (ANOVA). RESULTS: Regardless of the veneering ceramic used, all crowns showed a high color deviation from the reference teeth when applying the objective analysis (deltaE(A) 6.8 +/- 2.5, deltaE(B) 5.6 +/- 1.2, deltaE(C) 5.7 +/- 2.1). In addition, no significant differences were found between the deltaE of crowns and teeth for the 3 ceramics. In the framework-supported area, ceramic B showed a significantly lower difference in value (deltaL) compared to the reference teeth than the other 2 ceramics (deltaL(A) 4.9 +/- 2.3, deltaL(B) 1.1 +/- 2.1, deltaL(C) 4.1 +/- 1.5; P < .01 ANOVA). When performing the subjective analysis, ceramic B was chosen as the best match by a majority of observers (> 60%) in 4 of 6 patients. CONCLUSIONS: All 3 ceramics met the esthetic demands only to a limited extent. Ceramic B allowed for the most predictable result in terms of color stability.     

Racial differences in type of surgical procedure performed for proximal humerus fractures

Background  

Proximal humeral fracture constitutes a medical emergency on most occasions in which the decision to perform either open reduction and internal fixation (ORIF) or hemiarthroplasty is determined by the operating surgeon. Hemiarthroplasty is a more expensive and technically challenging procedure that requires compliance with rigorous and prolonged rehabilitation postsurgically. We assessed whether racial differences exist in utilization of hemiarthroplasty versus ORIF in patients with proximal humeral fracture.     

CaV2.1 channelopathies

Mutations in the CACNA1A gene that encodes the pore-forming α₁ subunit of human voltage-gated Ca_V2.1 (P/Q-type) Ca²⁺ channels cause several autosomal-dominant neurologic disorders, including familial hemiplegic migraine type 1 (FHM1), episodic ataxia type 2, and spinocerebellar ataxia type 6 (SCA6). For each channelopathy, the review describes the disease phenotype as well as the functional consequences of the disease-causing mutations on recombinant human Ca_V2.1 channels and, in the case of FHM1 and SCA6, on neuronal Ca_V2.1 channels expressed at the endogenous physiological level in knockin mouse models. The effects of FHM1 mutations on cortical spreading depression, the phenomenon underlying migraine aura, and on cortical excitatory and inhibitory synaptic transmission in FHM1 knockin mice are also described, and their implications for the disease mechanism discussed. Moreover, the review describes different ataxic spontaneous cacna1a mouse mutants and the important insights into the cerebellar mechanisms underlying motor dysfunction caused by mutant Ca_V2.1 channels that were obtained from their functional characterization.     

The Rapid Impact on Mortality Rates of a Dedicated Care Team Including Trauma and Emergency Physicians at an Academic Medical Center

Background: Trauma center designation can result in improved patient outcomes after injuries. Whereas the presence of trauma teams has been associated with improved trauma patient outcomes, the specific components, including the role of emergency medicine (EM)-trained, board-certified emergency physicians, have not been defined. Objective: To assess the outcomes of patients before and after the establishment of a dedicated trauma team that incorporated full-time EM-trained physicians with trauma specialists at a Level I trauma center at an academic institution. Methods: Secondary analysis of prospectively collected trauma registry data was performed to compare mortality rates of all treated trauma patients before and after this intervention. Results: The establishment of a dedicated specialty trauma team incorporating full-time EM presence including EM-trained, board-certified emergency physicians was associated with a reduction in overall non-DOA (dead on arrival) mortality rate from 6.0% to 4.1% from the time period preceding (1999–2000) to the time period after (2002–2003) this intervention (1.9% absolute reduction in mortality, 95% confidence interval [CI] 0.7%–3.0%). Among patients who were most severely injured (Injury Severity Score [ISS] ≥ 25), mortality rates decreased from 30.2% to 22.0% (8.3% absolute reduction in mortality, 95% CI 2.1%–14.4%). In comparison, there was minimal change in national mortality rates for patients with ISS ≥ 25 during the same time period (33% to 34%). Conclusions: The implementation of a dedicated full-time trauma team incorporating both trauma surgeons and EM-trained, board-certified or -eligible emergency physicians was associated with improved mortality rates in trauma patients treated at a Level I academic medical center, including those patients presenting with the most severe injuries.     

Conventional visual vs spectrophotometric shade taking for porcelain-fused-to-metal crowns: a clinical comparison

This study tested the shade match of single porcelain-fused-to-metal restorations with the adjacent dentition when the restorations were fabricated according to data from conventional visual shade matching or from a new spectrophotometric system. The samples of a Vita Classic shade guide were measured with the spectrophotometer to determine the CIE L*a*b* color parameters. Three clinicians independently selected the best match to a maxillary right or left incisor needing a restoration in 10 patients. The 10 incisors were then measured using a reflectance spectrophotometer. CIE L*a*b* coordinates were directly recorded on the spectrophotometer's detector area using a standard light source. Resulting conventional and spectrophotometric restorations were tested intraorally for best match with the adjacent incisor using conventional shade matching versus spectrophotometric measuring. Total color difference was calculated, and all groups were statistically analyzed. Initial shade evaluation matched for all three visual shade selections in two cases. In six cases only two evaluators matched, and in the remaining two cases all three visual selections differed. In contrast, in nine of 10 cases all three spectrophotometric shade selections matched. Additionally, in nine of 10 cases delta E values of visually assessed tooth shades were higher than spectrophotometrically assessed delta E values. Resulting delta E values for conventional crowns compared to spectrophotometric crowns were significantly higher. Finally, in nine of 10 cases spectrophotometric crowns were preferred over conventional crowns for definitive cementation when evaluated visually. Spectrophotometric shade analysis and communication can be used efficiently for fabrication of porcelain-fused-to-metal restorations.