RESUMO
Periods of soil water stress have been recurrent in the Cerrado region and have become a growing concern for Brazilian tropical pasture areas. Thus, the search for forage grasses more tolerant to water stress has intensified recently in order to promote more sustainable livestock. In a greenhouse experiment, the degree of water stress tolerance of nine tropical forage grass cultivars was studied under different soil water regimes. The investigation followed a 9 × 3 factorial design in four randomized blocks. Nine cultivars from five species of perennial forage grasses were tested: Urochloa brizantha ('BRS Piatã', 'Marandu', and 'Xaraés'), Panicum maximum ('Aruana', 'Mombaça', and 'Tanzânia'), Pennisetum glaucum ('ADR 300'), Urochloa ruziziensis ('Comum'), and Paspalum atratum ('Pojuca'). These cultivars were grown in pots under three soil water regimes (high soil water regime-HSW (non-stressful condition), middle soil water regime-MSW (moderate water stress), and low soil water regime-LSW (severe water stress)). Plants were exposed to soil water stress for 25 days during the tillering and stalk elongation phases. Twelve tolerance indices, including tolerance index (TOL), mean production (MP), yield stability index (YSI), drought resistance index (DI), stress tolerance index (STI), geometric mean production (GMP), yield index (YI), modified stress tolerance (k1STI and k2STI), stress susceptibility percentage index (SSPI), abiotic tolerance index (ATI), and harmonic mean (HM), were calculated based on shoot biomass production under non-stressful (YP) and stressful (YS) conditions. Soil water stress decreased leaf area, plant height, tillering capacity, root volume, and shoot and root dry matter production in most cultivars, with varying degrees of reduction among tropical forage grasses. Based on shoot biomass production under controlled greenhouse conditions, the most water-stress-tolerant cultivars were P. maximum cv. Mombaça and cv. Tanzânia under the MSW regime and P. maximum cv. Aruana and cv. Mombaça under the LSW regime. P. maximum cv. Mombaça has greater adaptability and stability of shoot biomass production when grown under greenhouse conditions and subjected to soil water stress. Therefore, this forage grass should be tested under field conditions to confirm its forage production potential for cultivation in tropical regions with the occurrence of water stress. The MP, DI, STI, GMP, YI, k2STI, and HM tolerance indices were the most suitable for identifying forage grass cultivars with greater water stress tolerance and a high potential for shoot biomass production under LSW regime.
RESUMO
A reabilitação oral de pacientes edentados totais inferiores através de implantes com carga imediata tem se tornado um procedimento seguro e de alta previsibilidade. Entretanto, a reabilitação de maxilas edêntulas continua sendo um dos procedimentos mais complexos da Implantodontia. O objetivo deste trabalho foi analisar a efetividade de implantes utilizados em reabilitação total superior submetida à carga imediata. Foram selecionados estudos clínicos de indivíduos que se submeteram a uma reabilitação total superior implanto-suportada com carga imediata. Os estudos foram analisados a partir de itens estabelecidos e, posteriormente, os dados obtidos foram transcritos para uma tabela que serviu de base para a análise dos resultados. A taxa de sucesso dos implantes foi medida segundo o tempo de acompanhamento do estudo e segundo o número de implantes por individuo. Segundo o tempo de acompanhamento, a taxa de sucesso foi de 98,5% quando acompanhados até dois anos e 96,5% quando acompanhados por um período de três a sete anos. Quanto ao número de implantes por individuo, a taxa de sucesso foi de 97,4% quando utilizados quatro implantes, 98,15% quando utilizados de cinco a sete implantes e 98,8% quando utilizados de oito a 12 implantes. Portanto, conclui-se que a taxa de sucesso dos implantes utilizados em protocolos totais superiores com carga imediata aumentou proporcionalmente ao número de implantes utilizados e diminuiu quanto maior for o tempo de acompanhamento do estudo.
The oral rehabilitation of total edentulous mandibular patients through immediate-loaded implants has become a safe procedure with a high predictability. However, the rehabilitation of edentulous maxilla is still one of the most complex procedures of dentistry. The objective of this study was to analyze the effectiveness of immediately loaded implants supporting fixed prostheses in the edentulous maxilla. The scientific articles had been analyzed through established item and later the screened data had been analyzed. The rate of success of the implants was measured according to time of follow- up of the study and according to the number of implants per individual. According to time follow-up, there was a success rate of 98.5% when followed for two years and 96.5% when followed for three to seven years. According to the number of implants per individual, the success rate was 97.4% when four implants were used, 98.15% when five to seven implants were used and 98.8% when eight to 12 implants were used. Therefore, it is concluded that the rate of success of implants used in total upper fixed protocols with immediate loading increases along with the number of implants used and decreases with the number of follow-up time intervals.
