Subgingival Ultrasound Curettage And Polishing The Tooth Surface Of The Scanning Electron Microscope

Objective:To study the effect on the root surfaces and the work efficacy following ultrasonic subgingival scaling with different output power and different parts of work tip. To research the impact of polishing on tooth surfaces after ultrasonic scaling. The mainly purpose of this experiment was to give an experimental evidence for the basic therapy of periodontal diseases. Methods:(1) Twenty root surfaces from ten teeth extracted for severe periodontal diseases, which with almost similar calculus, were randomly divided into group A or group B, the high power was set as "3" (group A) and the low power was set as "1" (group B), using the side (group A1 and B1) and the top (group A2 and B2) of work tip. The time for scaling was recorded and the surface feature of all the specimens was observed under scanning electron microscope (SEM). (2) Forty teeth for severe periodontal diseases were randomly divided into four groups, which after ultrasonic scaling on dental crown labial 1/2 surfaces and root labial 1/2 surfaces approaching dental cervix. Four groups were without polishing (group A), polished by 3M polishing paste (group B), by air-powder polishing (group C) and by silicon particles polishing (group D), observed the tooth surfaces under scanning electron microscope (SEM). Results:(1) The damage of root surfaces in group A1 and B1 was less severe, while more in group A2 and B2; there were less calculus and plaque residual on root surfaces in group A than in group B. Cementum exfoliation was observed in group A but not in group B. The operating time of group A was shorter than that of group B (P<0.01); however, there was no significant difference between group A1 and A2 or group B1 and B2 (P>0.05). (2) After the scaling without polishing group (group A), the tooth surfaces were rough or scratched or and had a small amount of calculus; after polished by 3M polishing paste (group B), the tooth surfaces were clear with minimal calculus and polishing scratches; the surfaces of air-powder polishing group (group C) were formation and had little calculus, but with more shallow dent; while the surfaces of silicon particles polishing group (group D) were highly clean with little or no calculus but had more polishing scratches. The damage of root surfaces was more severe than dental crown ones in the same groups after polishing. Conclusion:Calculus and plaque can be cleaned more effectively and the damage is less severe by using the side of work tip. Although the calculus can be cleaned more rapidly by using higher power set, the damage is more severe. After ultrasonic scaling, the teeth should be polished using to improve the clearness surfaces, polishing paste is the best tool on root surfaces.