Administration, Topical Aged Aged, 80 and over Anti-Infective Agents, Local--administration & dosage Dental Care for Aged--instrumentation Dental Care for Chronically Ill--instrumentation Dental Care for Persons with Disabilities--instrumentation Dental Devices, Home Care Dental Plaque--prevention & control Equipment Design Female Health Education, Dental--methods Humans Male Middle Aged Oral Hygiene--instrumentation Periodontal Index Povidone-Iodine--administration & dosage Toothbrushing--instrumentation