Humans; Male; Female; Child, Preschool; Child; Health Education, Dental/classification; Health Education, Dental/methods; Dental Care for Children/classification; Dental Care for Children/instrumentation; Dental Care for Children/methods; Bicuspid/physiology; Dental Caries/etiology; Dental Caries/prevention & control; Cuspid/physiology; Dental Arch/physiology; Dental Devices, Home Care/classification; Dental Devices, Home Care/standards; Dentifrices/classification; Dentifrices/pharmacology; Dentition, Permanent; Toothbrushing/classification; Toothbrushing/instrumentation; Toothbrushing/methods; Gingiva/physiology; Gingiva/physiopathology; Incisor/physiology; Molar/physiology; Oral Hygiene; Oral Hygiene/classification; Oral Hygiene/instrumentation; Dental Plaque/etiology; Dental Plaque/prevention & control; Dental Restoration, Temporary/classification; Dental Restoration, Temporary/methods; Tooth, Deciduous