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[Effect of ultrasonic scalers, burs and silicone points on the resins for denture bases].

BACKGROUND
Complete dentures in elderly patients often present a large build-up of dental calcolus. In order to avoid this leading to the onset of mycosis or other infections of the oral cavity, all the dental calcolus must be removed during check-ups.


METHODS
In order to analyse the consequences of removing the dental calcolus by mechanical means on the resin of the dentures, a polymethylmetacrylate (PMMA) plate was treated with a ultrasonic scaler, with rotating silicone points and with tungsten carbide burrs mounted on a straight hand-grip. The specimens were observed under a light stereomicroscope and their surface was analysed using a surface roughness tester. Observation under the stereomicroscope showed that in all cases the smooth surface of the resin is damaged and modified.


RESULTS
The analysis using the surface roughness tester revealed that only very limited quantities of resin are removed whatever the method. Using the lateral edge of the ultrasonic scaler tip and the rotating silicone points mounted on a hand-grip were the techniques that gave the best results, causing the least abrasions.


CONCLUSIONS
The results obtained show that after removing the dental calcolus with the instruments tested, the dentures need to be polished in order to prevent the roughness and irregularities caused by the instruments from favouring plaque retention and the consequent reformation of dental calcolus.