| Autor: |
Barbosa PIZ; Graduate Program in Pediatric Dentistry, School of Dentistry of Ribeirão Preto, University of São Paulo(FORP/USP), Ribeirão Preto, São Paulo, Brazil., Lima RB; Graduate Program in Pediatric Dentistry, School of Dentistry of Ribeirão Preto, University of São Paulo(FORP/USP), Ribeirão Preto, São Paulo, Brazil., Marubayashi LM; Graduate Program in Pediatric Dentistry, School of Dentistry of Ribeirão Preto, University of São Paulo(FORP/USP), Ribeirão Preto, São Paulo, Brazil., Oliveira HF; Department of Internal Medicine, Ribeirão Preto School of Medicine, University of São Paulo (FMRP/USP), Ribeirão Preto, São Paulo, Brazil., Silva RABD; Graduate Program in Pediatric Dentistry, School of Dentistry of Ribeirão Preto, University of São Paulo(FORP/USP), Ribeirão Preto, São Paulo, Brazil.; Department of Pediatric Clinics, School of Dentistry of Ribeirão Preto, University of São Paulo(FORP/USP), Ribeirão Preto, São Paulo, Brazil., Nelson-Filho P; Graduate Program in Pediatric Dentistry, School of Dentistry of Ribeirão Preto, University of São Paulo(FORP/USP), Ribeirão Preto, São Paulo, Brazil.; Department of Pediatric Clinics, School of Dentistry of Ribeirão Preto, University of São Paulo(FORP/USP), Ribeirão Preto, São Paulo, Brazil., Arnez MFM; Graduate Program in Pediatric Dentistry, School of Dentistry of Ribeirão Preto, University of São Paulo(FORP/USP), Ribeirão Preto, São Paulo, Brazil., Paula-Silva FWG; Graduate Program in Pediatric Dentistry, School of Dentistry of Ribeirão Preto, University of São Paulo(FORP/USP), Ribeirão Preto, São Paulo, Brazil.; Department of Pediatric Clinics, School of Dentistry of Ribeirão Preto, University of São Paulo(FORP/USP), Ribeirão Preto, São Paulo, Brazil., Queiroz AM; Graduate Program in Pediatric Dentistry, School of Dentistry of Ribeirão Preto, University of São Paulo(FORP/USP), Ribeirão Preto, São Paulo, Brazil.; Department of Pediatric Clinics, School of Dentistry of Ribeirão Preto, University of São Paulo(FORP/USP), Ribeirão Preto, São Paulo, Brazil. |
| Abstrakt: |
The objective of this study was to compare the activation of gelatinases in dentin-enamel junction (DEJ) and underlying dentin of permanent teeth after experimental radiotherapy in conventional and hypofractionated modalities. Newly extracted third molars (n = 15) were divided into three experimental radiotherapy groups: control, conventional (CR), and hypofractionated (HR) (n = 5 per group). After in vitro exposure to ionizing radiation, following standardized protocols for each modality, a gelatinous substrate was incubated on the tooth slices (n = 10 per group). Activation of gelatinases was measured by in situ zymography, expressed in arbitrary fluorescence units (mm2) from three tooth regions: cervical, cuspal, and pit. Fluorescence intensity was compared among radiotherapy protocols and tooth regions in each protocol, considering a significance level of 5%. Considering all tooth regions, the fluorescence intensity of the CR group was higher than the HR and control groups, both in DEJ and underlying dentin (p <0.001). In addition, the fluorescence intensity was higher in underlying dentin when compared to DEJ in all groups (p <0.001). Considering each tooth region, a statistically significant difference between CR and HR was only observed in the pit region of underlying dentin (p <0.001). Significant and positive correlations between fluorescence intensities in DEJ and underlying dentin were also observed (p <0.001). Experimental radiotherapy influenced the activation of gelatinases, as well as exposure to the conventional protocol can trigger a higher activation of gelatinases when compared to hypofractionated, both in DEJ and underlying dentin. |
