A Retrospective Clinical Study on 1075 Lithium Disilicate CAD/CAM Veneers with Feather-Edge Margins Cemented on 105 Patients.

PURPOSE: To evaluate the clinical performance of lithium disilicate (LiDiSi) computer-aided- design/computer-assisted-manufacturing (CAD/CAM) veneers with feather-edge margins. METHODS: Over 4 years (2015-2019), 1075 LiDiSi veneers with feather-edge margins were fabricated with a fully digital workflow and cemented on 105 patients. The outcome variables were survival of the restorations, colour matching, quality of the ceramic surface, presence of marginal discolouration and marginal integrity. The last four variables were assessed using the modified California Dental Association (CDA) and Ryge criteria. RESULTS: The mean observation period was 30.8 months. The cumulative survival rate was 99.83%. At the last follow-up control, the colour matching of the surviving 1074 restorations was rated Alpha (1064 veneers, 99.06%) and Bravo (10 veneers, 0.94%); the ceramic surface was rated Alpha (1070 veneers, 99.62%) and Bravo (4 veneers, 0.38%); the marginal discolouration was rated Alpha (1069 veneers, 99.53%) and Bravo (5 veneers, 0.47%); and the marginal integrity was rated Alpha (1070 veneers, 99.62%) and Bravo (4 veneers, 0.38%). CONCLUSION: CAD/CAM LiDiSi veneers with feather-edge margins fabricated with a fully digital workflow showed good clinical performance in terms of survival, colour matching, ceramic surface, marginal discolouration and integrity. Further, prospective and long-term studies are needed to confirm these positive results.

Continuous Scan Strategy (CSS): A Novel Technique to Improve the Accuracy of Intraoral Digital Impressions.

PURPOSE: To present the results obtained with the "Continuous Scan Strategy" (CSS), a direct intraoral scanning technique based on the connection of the implant scan bodies (SBs) with thermoplastic resin. METHODS: 40 patients were restored with 45 long-span monolithic implant-supported zirconia restorations (10 partial prostheses [PP] and 35 full arches [FA]) fabricated via a full-digital workflow after the capture of an intraoral impression (Trios3®) using the CSS technique. The primary outcomes were the marginal adaptation and passive fit of the superstructures, checked at T0 (intraoral try-in of polyurethane or metal replica of the final prosthesis) and T1 (delivery of the final zirconia restoration). The secondary outcomes, registered at T2 (2 years after the delivery of the final prosthesis), were implant survival, prosthetic success, and complications. A throughout statistical analysis was performed. RESULTS: At T0, 40/45 replicas demonstrated a perfect passive fit and adaptation. At T1, one prosthesis had fractured, and at T2, an additional prosthesis had fractured and one had chipped. The implant survival rate was 100%. The prosthetic success was 93.3%. CONCLUSIONS: CSS seems to represent a viable option for capturing accurate intraoral digital impressions for the fabrication of precise long-span implant-supported restorations.

Effects of Digit Orientation on Gecko Adhesive Force Capacity: Synthetic and Behavioral Studies.

In this study we developed an analytical relationship between adhesive digit orientation and adhesive force capacity to describe the tendencies of climbing organisms that use adhesion for climbing to align their toes in the direction of loading, maximizing adhesive force capacity. We fabricated a multi-component adhesive device with multiple contact surfaces, or digits, to act as a model system mimicking the angular motion of a foot and found the synthetic experiments agree with the developed analytical relationship. In turn, we find that observations of gekkonid lizards climbing on vertical substrates correlate well with our analytical relationship; a reduction in toe spacing is seen on the forelimbs when the animals are facing up. Interestingly, the toes on the hindlimbs tend to have an increase in spacing, possibly a mechanism for stabilization rather than load-bearing.

Electrocardiographic diagnosis of remote posterior wall myocardial infarction using unipolar posterior lead V9.

The accuracy of four electrocardiographic criteria for diagnosing remote posterior myocardial infarction was assessed prospectively in 369 patients undergoing exercise treadmill testing with thallium scintigraphy. Criteria included the following: 1) R-wave width greater than or equal to 0.04 s and R-wave greater than or equal to S-wave in V1; 2) R-wave greater than or equal to S-wave in V2; 3) T-wave voltage in V2 minus V6 greater than or equal to 0.38 mV (T-wave index); 4) Q-wave greater than or equal to 0.04 s in left paraspinal lead V9. Twenty-seven patients (7.3 percent) met thallium criteria for posterior myocardial infarction, defined as a persistent perfusion defect in the posterobase of the left ventricle. Sensitivities for the four criteria ranged from 4 to 56 percent, and specificities ranged from 64 to 99 percent. Posterior paraspinal lead V9 provided the best overall predictive accuracy (94 percent), positive predictive value (58 percent), and ability to differentiate patients with and without posterior myocardial infarction of any single criterion (p less than .0001). Combining the T-wave index with lead V9 further enhanced the diagnostic yield: the sensitivity for detecting posterior infarction by at least one of these criteria was 78 percent, and when both criteria were positive, specificity was 98.5 percent. It is concluded that a single, unipolar posterior lead in the V9 position is superior to standard 12-lead electrocardiographic criteria in diagnosing remote posterior myocardial infarction, and that combining V9 with the T-wave index maximizes the diagnostic yield.