The resonant characteristics of ultrasonic files driven by the Cavi-Endo unit were examined. The investigation was carried out by evaluating the pattern of oscillation and the power emitted by the ultrasonic files. It was observed that the files oscillated in a sinusoidal fashion, exhibiting a standing wave pattern along the file. The power emitted was found to be directly proportional to the flexibility of the file. Such behaviour is typical of a system that exhibits resonance.
Sterilisation is an essential step in the reprocessing of reusable dental instruments including burs that have become contaminated, or potentially contaminated. Transmission of disease or infection may happen as an effect of improper sterilisation of the reused instruments. Dental burs are one of the essential tools in any conservative dental procedures, which undergo multiple sterilisation cycles before being discarded. However, repeated sterilisation process is associated with the reduction in cutting efficiency of a bur that is potentially due to corrosion. Thus, this study aims to compare the effect of two sterilisation methods on cutting efficiency of a diamond bur that is commonly used in dental procedures. Methods: 30 fissure diamond burs were randomly divided into three sterilisation groups: Group A (dry heat), B (steam under pressure) and C (control). Each bur was used to cut teeth for 45 seconds for ten cycles. Between cuts, the burs underwent sterilisation based on their sterilisation groups. Amount of cutting weight was measured after each cut. Results: This study shows that no significant difference (p>0.05) in the cutting efficiency of the burs following sterilisation of Groups A and B. However, there is a significant mean difference (p