Background: Acrylic and bisacryl resins are widely used both during the temporization phase as well as for provisional restorations and the effect of external agents on dentin sensitivity can be reduced by the obliteration of the tubules.

Objective: The purpose of this study was to evaluate diffusion of methyl methacrylate monomer through dentin by high performance liquid chromatography (HPLC) after three different desensitizing procedures during the fabrication of two different provisional crown materials.

Materials and Methods: Forty extracted restoration and caries free human premolar teeth were used in this study. Thermoplastic vacuum formed material was used as a matrix to fabricate provisional restorations for each tooth before crown preparation. Teeth were prepared for a metal supported ceramic crown with 1 mm shoulder margins and then crown parts were separated from cementoenamel junction with a carborundum disk perpendicular to the long axis of the teeth. To the cementoenamel junction of each tooth a polypropylene chamber was attached that contains 1.5 cm3