The purpose of this study was to prepare improved education guideline by grasping parts and items felt difficult to apply instruments by the students of the dental hygiene department in the practice of oral prophylaxis using manikin and analyzing factors influencing the satisfaction at the oral prophylaxis subject. To achieve this purpose, 285 senior students of the dental hygiene department located in the Kwangju. Jeonnam area who took theory and practice courses of oral prophylaxis but only practiced the manikin from the second semester of 1st year were selected as the subjects. The following results were obtained. 1. In the manikin, the most difficult part was maxillary anterior lingual in the use of explorer, sickle scaler, and universal curet, and maxillary right posterior lingual was in the use of gracey curet. In the dentiform, the most difficult item was instrument stroke in the use of explorer, sickle scaler, universal curet and gracey curet. 2. The highest stressor was the lack of knowledge and skill in practice of oral prophylaxis, followed by the lack of confidence, and difference between theory and practice in oral prophylaxis. The overall practice satisfaction was 3.23 at oral prophylaxis. The highest satisfaction was found in patient and operator position(3.51), followed by basic skill(3.34), the way to use hand instrumentation(3.16), and the way to use oral examination instrumentation(3.01). 3. According to school records, satisfaction at oral prophylaxis practice satisfaction was 3.36 of good, 3.24 of fair, and 3.06 of poor, suggesting significant difference(p<0.05). Students who participated just in practice during a school term showed 3.47 of satisfaction. The highest satisfaction was found in a full-time professor as a professor in charge(3.24) and there was significant difference(p<0.05). 4. The highest correlated factor between oral prophylaxis theory and practice satisfaction was curriculum satisfaction. The use of hand instrumentation was found to have the greatest effect on the practice satisfaction at oral prophylaxis, followed by basic skill, the way of basic instrumentation, and position. There was statistically significant difference(p<0.01).