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O presente estudo teve como objetivo a importância da vacinação contra Coronavírus (COVID-19; SARS-COV-2) no Brasil, buscando descrever a sua eficácia e a importância da conscientização da imunização. Trata-se de uma revisão bibliográfica do tipo revisão integrativa da literatura (RIL), que apresenta abordagem qualitativa. Para a realização desse estudo, foram consultadas as bases de dados: Medical Literature Analysis and Retrieval System Online (MEDLINE), Scholar Google, Literatura Latino-americana e do Caribe em Ciências da Saúde (LILACS), Scientific Eletronic Library Online (SCIELO), Repositórios e Google acadêmico. Utilizou-se os Descritores em Ciências da Saúde (DeCS) de forma associada: “COVID-19”, “vacina”, “Brasil”, "Imunização" e “Coronavírus”. Os critérios de inclusão foram: artigos disponibilizados na íntegra, disponíveis nos idiomas português e inglês e publicados entre os anos de 2019 e 2021. Após a aplicação dos critérios de inclusão, restaram 18 estudos. Ao longo da história observa-se que as práticas de vacinação programadas e organizadas evitam milhões de óbitos e controla a evolução de várias doenças. No Brasil, a cobertura vacinal se iniciou por dois grupos prioritários: profissionais da saúde por estarem na linha de frente e população idosa, pelo maior risco de morte por COVID-19 que aumenta com a idade, especialmente entre os portadores de doenças crônicas.

Purpose To compare the fracture resistance before and after cyclic fatigue assays of ceramic crowns with customized zirconia abutments when screw retained and cemented onto implants. Materials and Methods The sample of this study consisted of 40 ceramic crowns with zirconia infrastructure fixed onto external hexagonal implants. The crowns were distributed into two groups (n = 20): Screw-retained and cemented crowns. Half the crowns of each group (n = 10) underwent compression until fracture and the other half (n = 10) underwent cyclic fatigue and subsequent compression until fracture. The cyclic fatigue test was carried out using an electromechanical fatigue device (loads from 0 to 100 N, 2 Hz frequency, in distilled water, at 37°C for a period of 1 million cycles). The compression test was carried out using a universal testing machine with a 0.5 mm/min speed and 5 KN load cell. After fracture, the crowns were classified according to the type of fracture. Student's t test (p < 0.05) was used for statistical analysis. Results The cyclic fatigue altered neither the mean fracture resistance of the screw-retained crowns (before = 1068.31 N, after = 891.49 N; p > 0.05) nor that of the cemented crowns (before = 2117.78 N; after = 2094.81 N; p > 0.05); however, the mean fracture resistance of the cemented crowns was higher than that of the screw-retained crowns both before (p < 0.001) and after (p < 0.001) the cyclic fatigue. Fractures occurred most frequently in the ceramic veneer, followed by fracture of some of the copings. Conclusion The ceramic crowns cemented onto the customized zirconia abutments offered greater fracture resistance than ceramic crowns with customized zirconia abutments screw retained onto implants. The cyclic fatigue did not seem to influence the fracture resistance of these crowns, whether cemented or screw retained onto implants. Fracture of the veneering ceramic was the predominant failure in this study.

Statement of problem The maintenance of the mechanical stability of implant-abutment connections is relevant to the clinical success of implant-supported restorations. However, the reduction in the conical area of abutments with an internal hexagonal index may result in a biomechanical disadvantage in Morse taper connections. Purpose The purpose of this in vitro study was to evaluate the influence of an internal hexagonal index on the removal torque and tensile removal force of different Morse taper connection abutments submitted to thermomechanical cycling. Material and methods Forty Morse taper implants with their respective abutments were divided into 4 groups (n=10): straight abutment without index (PRNI); straight abutment with index (PRI); angled abutment without index (PANI); and angled abutment with index (PAI). Each abutment received an insertion torque of 15 Ncm, and the removal torque was recorded before and after thermomechanical cycling (10 6 cycles, 2 Hz, load of 130 N). After cycling, the groups were submitted to tensile testing at 0.5 mm/min under a load of 500 N until displacement of the abutment. A paired t test was performed for the intragroup analysis of removal torque before and after cycling and 2-way ANOVA followed by the Tukey Honestly Significant Difference (HSD) test was used for intergroup comparison (α=.05). Results Statistical analysis showed significant differences in intragroup removal torque values before compared with after thermomechanical cycling ( P P =.028) was significant for tensile removal force. Conclusions The type of abutment did not significantly influence the removal torque or tensile removal force after cycling. However, the presence of the internal hexagonal index significantly reduced the force necessary to dislodge the abutment from the implant.