Pulp and dentin modifications that occur after direct and indirect overlay with materials on the calcium hydroxide-base

Abstract

When pulp tissue gets exposed, therapy procedures are supposed to promote healing and to ease forming of reparative dentin in order to preserve vitality and health of the pulp. Vital pulp therapy (VPT) procedure includes removal of the local irritants as well as application of protective materials directly or indirectly on tooth pulp. Vital pulp therapy may be used for the treatment of the reversible pulp diseases in order to promote root development and to form apical region which will ensure correct endodontic tooth treatment in later stages. There are numerous controversies concerning vital pulp therapy but mostly related to the choice of the materials, correct technique and evaluation of the final therapy results. The goal of the experimental research is to use scanning electron and polarized microscopy to analyze modifications on cellular and extracellular components of the tooth pulp after direct and indirect overlaying with materials on the calcium hydroxide basis (Calcimol VOCO USA). We will also determine the appearance of dental surface after direct and indirect overlaying and if Calcimol proves good and effective in dentinogenesis, we will propose it for clinical usage. Research has been conducted on experimental animals (pig). Materials used in this research were on calcium hydroxide - base, Calcimol. V class preparation has been applied on the teeth of the experimental group. Eleven teeth have been overlaids directly and the same number of teeth has been overlaid indirectly. After the preparation, materials based on calcium hydroxide have been applied and cavity has been closed with materials from the glass ionomer cement group (FUJI IX GC Japan). Teeth that were treated with pulp perforation had their chambers filled with materials on calcium hydroxide-base and their cavities were closed with glass ionomer cement (FUJI IX GC Japan). Correctly prepared teeth have been observed with SEM and polarization microscopes. Observing and analyzing of the results with polarization and scanning electron microscope in comparison with control group showed that gained results may have significant clinical implication in biological pulp treatment. Directly applied Calcimol observed through polarization microscope points to intensive changes in blood vessels and beginnings of erythrocyte disintegration, distinct extravasation, and appearance of the small necrotic spots. SEM analyzes shows contact of the amalgam-Calcimol without new amorphous dentinal structures. Indirectly applied Calcimol observed through polarization microscope points to newly formed dentinal structures, calcification cores surrounded by huge cells and blood vessels presence. SEM analyzes shows clear border between newly formed dentinal tubules and ordinary dentinal structure. Gained results suggest application of the Calcimol as a material for indirect pulp overlay while its application in indirect overlay isn't indicated.