It is considered that clinical application of an air-powder abrasive system for cleaning the cervical area has some effects on gingiva sprayed. These effects are due to changes in distance, angle, et. of the spray. The authors conducted this research to investigate the influence exert on gingiva. Six males, aged 23-25, with normal upper central incisor gingiva were used as subjects. Spraying location and duration were decided as 10 seconds for the cervical area, and one second for direct spray of gingiva. Splaying angle was 60° at a distance of 5mm. Macroscopic and gingival replica observations, and examination of bleeding index and gingival crevicular fluid were carried out before and immediatery after spraying, and one, two, three and seven days folowing spraying.
The following results were obtained.
1. Both the ten second cervical area and one second direct sprayings caused marginal gingival damage that required a one week period to recover macroscopically.
2. Bleeding index and gingival crevicular fluid increased immediately after spraying but soon returned to pre-spraying levels by the next observation period.
3. Damage was discerned by replica observation even one week after spraying in more than half the subjects.
