SEM analysis of dentin intratubular structures in non-carious cervical lesions

Objectives: To study clinically and by SEM the occurrence of dentin intratubular structures (ITS) in NCCL with respect to the counterpart lesion-free lingual aspect of the tooth and to the presence of dentin hypersensitivity (DH). The null hypothesis is that ITS are an event restricted to NCCL. Methods: Dentin samples from buccal and lingual aspects of 14 extracted human teeth with NCCL were collected. Patient's age, gender and occurrence of DH were recorded before tooth extraction. After extraction the teeth were immediately fixed with Karnovsky and then fractured alongside the body of the lesion and its lingual counterpart as well. Afterwards the samples were post fixed, critical-point-dried and sputter-coated with gold following the protocol for SEM. The fractured surfaces of each specimen were examined for the presence of dentin casts (ITS). Results: Both buccal NCCL and lesion-free lingual surfaces presented ITS. These ITS extended from the dentin surface up to the pre-dentin-dentin limit. Four NCCL were non-sensitive, while 10 showed different degrees of hypersensitivity. No differences were found in dentin from hypersensitive and non-sensitive lesions. Conclusions: It seems correct to suggest that the ITS are common event of dentine which, for any circumstance has been displayed to the buccal environment for long-lasting periods. So, the null hypothesis was not confirmed under the light of the method used. ITS can occur in both hypersensitive and non-sensitive dentin.