RESUMO
OBJECTIVES: The aim of this study was to assess the presence of enamel craze lines (ECLs), part of the spectrum of the so-called cracked tooth syndrome, on the surface of teeth irradiated in vivo. STUDY DESIGN: Forty teeth extracted from patients with head and neck cancer were paired, matched, and equally divided into 4 groups: noncarious irradiated (G1); noncarious control (G2); radiation-related caries (RRC) (G3), and carious control (G4). Samples were examined for ECL detection with a fiberoptic transillumination device and photographed, and ECL mean size, number, and patterns of topographic distribution in tooth crown were determined. Groups were compared accordingly: G1 versus G2; G3 versus G4. RESULTS: We analyzed 538 ECLs, of which 30.1% were found in noncarious irradiated teeth, 19.3% in noncarious controls, 27.6% in RRC, and 23% in carious controls. Non-carious irradiated teeth presented higher quantities of ECL than non-carious control (P < 0.05). Higher incidences of ECLs were identified in specific enamel topographies of anterior G1 and G3 samples (P <.05). There was no correlation between ECL size/numbers and radiation isodose delivery to teeth. CONCLUSIONS: Increased incidence of ECLs may indicate weakened enamel structure in irradiated teeth, and this may play a role in the onset and progression of RRC.