Introduction: The teaching of manual skills and competencies is among the most time-consuming aspects of oral health-care education, especially when large groups of students are involved. Video has been repeatedly used as an educational tool with varying results. Purpose: The present study aimed to investigate theeffectiveness ofacomputer-based video support system during practical training ofmanual skills and competencies related to periodontal treatment. Materials and Methods: Eighty-four students were randomized into 9 groups: 5 experimental and 4 control groups. The control groups received instruction in the use of scaling and root planing instruments during a 7-hour seminar, and 2 hours of manual practice. The experimental groups received the same instruction, but in addition had access to a computer-based video support system, the Visual Training System (VTS), during practical training. During the 2-hour long practice session, all students practiced 21 different procedures, which were video recorded. The videos were later evaluated by an independent observer. Results: On the whole, the students in the experimental group performed significantly better than their colleagues in the control group. Specifically, the groups that utilized the VTS video support performed significantly better in 9 of the 21 procedures tested. Conclusion: These results suggest that this computer-based video support can be an effective aid in the teaching of manual skills related to oral health care. Keywords: dental education, effectiveness of teaching, effectiveness of learning, periodontology, psychomotor skills, video support