title: Effect of systematic oral hygiene instruction on oral health among 13 year old schoolchildren.
mesh_terms: D000293:Adolescent; D003742:Dental Devices, Home Care; D003773:Dental Plaque / Q000517:prevention & control; D005260:Female; D005500:Follow-Up Studies; D005884:Gingival Hemorrhage / Q000517:prevention & control; D006267:Health Education, Dental; D006801:Humans; D008297:Male; D009910:Oral Hygiene; D010353:Patient Education as Topic; D014099:Toothbrushing