United States National Aeronautics and Space AdministrationSpace FlightAstronautsCosmic RadiationSpacecraftWeightlessnessNitrate ReductaseNitratesDental InstrumentsSurgical InstrumentsReproducibility of ResultsPsychometricsQuestionnairesQuality of LifeFactor Analysis, StatisticalLaparoscopesEquipment DesignRoot Canal PreparationSickness Impact ProfileHealth Status IndicatorsTranslations