Effect of Periodontal Instrumentation on Tooth Structure Exposure to Ionizing Radiation: In Vitro Study

This study aimed to evaluate the effects of different scaling protocols on the morphology and roughness of the root dentin substrate exposure to ionizing radiation. One hundred and thirty extracted bovine incisors were randomly divided into two groups (n=65): non-irradiated (NIR) and irradiated (IR). Each group was initially subdivided into three subgroups according to the type of non-surgical periodontal protocol: NIT: no instrumentation; HS: hand scaling with 15 apical-coronal instrument movements; US: ultrasonic scaling with 15 apical-coronal cycles. Subsequently, all samples were subjected to the prophylaxis protocol, being subdivided into the following groups: NIT/PP: prophylaxis with a fine prophylactic paste using a rubber cup for 15 seconds; HS/PP: Hand scaling followed by the prophylaxis protocol; US/PP: Ultrasonic scaling followed by the prophylaxis protocol. The roughness of the root dentin surface was measured with a profilometer (Ra/Rz - μm), and the morphology of the dentin surfaces was analyzed using scanning electron microscopy (SEM). The analyses were conducted before and after the prophylaxis protocol. In the absence of prophylaxis, the roughest surfaces were observed after ultrasonic instrumentation followed by hand instrumentation for both IR and NIR groups. No difference in Ra and RZ values between HS/PP and US/PP was observed for both substrates. For the IR group, the prophylaxis resulted in similar Ra and RZ values for both instrumentation groups in comparison to no instrumentation. Ordinal logistic regression showed that both HS and US resulted in higher scores than NIT, irrespective of IR presence. In conclusion, the IR showed a rougher root surface for both HS and US in comparison to NIR. However, the prophylaxis procedure significantly reduced the roughness of root surfaces after both instrumentation procedures.