Response of human pulps to dental materials applied in deep cavities

Objective: Evaluate the response of the pulpo-dentin complex following application of different dental materials in human teeth. Methods: Deep class V cavities were prepared on the buccal surface of 26 sound premolars. In Group 1, the cavity walls (dentin) and enamel were etched with 32% phosphoric acid and the adhesive system One Step (OS- BISCO) was applied. In Groups 2 and 3, before total etching, the cavity floor was lined with the glass-ionomer cement - Vitrebond (VIT- 3M) or the calcium hydroxide cement - Dycal (DY- DENTSPLY), respectively. The cavities were restored with Z-100 resin composite (3M). The teeth extracted between 5 and 30 days were prepared for microscopic examination. Five-micron thick sections were stained with H/E, Masson´s trichrome and Brown & Brenn techniques. Results: In Group 1, the inflammatory response was more evident than in Groups 2 and 3. Diffusion of resin components accross dentinal tubules was observed only in Group 1, in which the intensity of pulp response increased as the remaining dentin thickness decreased. Bacteria were evidenced in the lateral walls of two samples (Group 2) which exhibited no inflammatory response or tissue disorganization. Conclusions: Acid etching followed by application of the adhesive system One Step in very deep class V cavities can not be recommended as adequate procedures. In this clinical condition, the cavity floor should be lined with a biocompatible dental material, such as Vitrebond or Dycal.