Resistencia a la fractura de coronas dentales fabricadas análogamente vs tecnología cad-cam. Estudio In vitro / Fracture resistance of analogally made dental crowns vs cad-cam technology. In vitro study

Resumen Antecedentes. La resistencia a la fractura de las coronas puede tener influencia en su ocurrencia, de acuerdo con el método de fabricación usado, ya sea análogamente o por medio de tecnología Cad-Cam. Objetivo. Comparar la resistencia a la fractura de las coronas individuales realizadas por dos métodos de fabricación, bajo diseño asistido por ordenador y fabricación computarizada (CAD-CAM) e inyectadas. Método. Estudio in vitro. Tamaño de la muestra 20 coronas en dos grupos: 10 coronas bajo tecnología CAD-CAM y 10 coronas inyectadas. Fueron sometidas a cargas compresivas en una máquina de ensayos universal, con una velocidad de 1mm/min y una carga de celda de 5kN hasta obtener la fractura máxima de estas. Los datos se analizaron estadísticamente utilizando las pruebas Shapiro Wilk, Mann Whitney p=0,05. Resultados. Las coronas fabricadas por Cad-Cam obtuvieron un mínimo de 602,5 Newton y un máximo de 1093 Newton, mientras que las coronas fabricadas análogamente obtuvieron un mínimo de 525,2 Newton y un máximo de 1773 Newton en el experimento con la máquina de ensayo universal para lograr su fractura. Se obtuvo una diferencia significativa en la prueba de resistencia a la factura entre ambos métodos de fabricación (p <0,001). Conclusión. Las coronas de Disilicato de litio Prensadas obtuvieron una mayor resistencia a la fractura que las coronas fabricadas via CAD-CAM.

Abstract Background. The fracture resistance of the crowns may have an influence on their appearance, according to the method of making them, either analogously or by means of Cad-Cam technology. Objective. To compare the resistance to the fracture of the individual crowns made by two manufacturing methods, under computer-aided design and computerized manufacturing (CAD-CAM) and injected. Methods. In vitro study. Sample size 20 crowns in two groups: 10 crowns using CAD-CAM technology and 10 crowns injected. Crowns were subjected to compressive loads in a universal testing machine, with a speed of 1mm / min and a cell load of 5kN until obtaining the maximum bill for these. Data were statistically analyzed using the Shapiro Wilk tests, Mann Whitney p = 0.05. Results. Crowns manufactured by Cad-Cam obtained a minimum of 602.5 Newton and a maximum of 1093 Newton, while the crowns manufactured analogously obtained a minimum of 525.2 Newton and a maximum of 1773 Newton in the experiment with the machine Universal test to achieve their fracture. A significant difference was obtained in the invoice resistance test between both manufacturing methods (p <0.001). Conclusion. Pressed Lithium Disilicate crowns obtained higher fracture resistance than crowns under design and manufacturing by computer (CAD-CAM).

Prosthodontic practice during the COVID-19 pandemic: prevention and implications

Abstract: The objective of this review is to identify preventive measures for COVID-19 to safeguard dental professionals providing prosthodontic dental care. Electronic searches were performed in PubMed, Scopus, and Cochrane databases using the following descriptors and/or words: "COVID-19," "SARS-CoV-2," "Dental practice," "Prosthodontics," and "Dental infection control." Prosthodontists are at high risk for exposure to the novel coronavirus through aerosols and possibly contaminated surfaces and indirect contact with dental laboratories and dental technicians through impressions, dental stone casts, and fixed and removable prosthetic appliances. Therefore, preventive measures should be implemented, including performing emergency treatments only, rescheduling patients with suspected disease, disinfecting surfaces and prosthodontic materials with biocidal substances, and using protective equipment such as N95 masks, disposable gowns, and face-shields.

Ligas metálicas empregadas na confecção de retentores intrarradiculares nas Cidades de João Pessoa e Campina Grande–PB / Alloys employed in the manufacture of seals intraradical cities in Joao Pessoa and Campina Grande-PB

Objetivo: Identificar os tipos de ligas metálicas que sãoutilizadas na fundição de retentores intrarradiculares em 20laboratórios de prótese dentária nas cidades de João Pessoae Campina Grande. Material e Métodos: Dois examinadorescalibrados preencheram um formulário contendo as seguintesinformações em uma amostra de 400 retentores: 1)Localização do retentor na arcada dentária, liga metálicaempregada, nome comercial e se o dentista indicava a liga aser empregada na fundição. Resultados: Em João Pessoa,45,71% dos retentores foram confeccionados para dentesanteriores e (54,29%) para os posteriores (54,29%); emCampina Grande, 47,50% eram anteriores e 52,55%posteriores. As ligas mais utilizadas em João Pessoa foram abase de níquel-cromo (87,5%) e de cobre-zinco-alumínio(6,5%). Em Campina Grande, as de níquel-cromo (50%) ecobre-zinco-alumínio (50%). Conclusões: Na cidade de JoãoPessoa, as ligas metálicas mais empregadas foram à basede níquel-cromo; na cidade de Campina Grande foram à basede cobre-alumínio e níquel-cromo; na maioria das vezes, aseleção da liga metálica tem sido uma decisão do técnico deprótese dentária.

Objective: To identify the types of metal alloys used in thecasting of intraradicular retainers in 20 prosthesis laboratoriesin the cities of João Pessoa and Campina Grande. Materialand methods: Two calibrated examiners completed a formcontaining the following information about 400 retainers:location of the retainer in the dental arch, metal alloy used,trade name and presence or not of a statement by the dentistindicating the alloy to be used in the casting. Results: In JoãoPessoa, 45.71% of the intraradicular retainers were madefor anterior and 54.29% for posterior teeth; in CampinaGrande, 47.50% were for anterior and 52.55% for posteriorteeth. Most of the alloys used in João Pessoa were based onnickel-chromium (87.5%) and copper-zinc-aluminum (6.5%)materials. In Campina Grande, there was predominance ofnickel-chromium (50%) and copper-zinc-aluminum (50%).Conclusions: In João Pessoa, most of metal alloys used werebased on nickel-chromium material, whereas in the city ofCampina Grande there was predominance of copperaluminumand nickel-chromium; in most cases, the selectionof the alloy was a decision made by the prosthesis technician.