Direct capping with four different materials in humans: histological analysis of odontoblast activity

Pulp inflammation in restored teeth is mainly due to the presence of bacteria or bacterial products introduced by microleakage around the restoration or to the material toxicity. Recent knowledge has permitted a precise identification of the risks for pulpal irritation associated with adhesive materials and procedures. The purpose of this work was to evaluate the cellular events that occur in direct pulp exposure capped using different materials. Twenty-four vital teeth without caries, scheduled for extraction for orthodontic reasons, were selected. After a control of the hemostasis, each pulp was directly capped with a different material. The samples were randomly divided into four groups of six specimens each: group I: dental-bonding agent (Solist) followed by resin composite (Ecusit); group II: dental adhesive (Prompt) and resin composite (Pertac II); group III: traditional calcium hydroxide (Dycal) plus resin composite (Ecusit); group IV: light-curing calcium hydroxide (Ultrablend Plus) and amalgam (Dentsply). After 15 days the teeth were extracted, immediately fixed in 10% buffered formalin, embedded in resin (7200 Technovit), and prepared for thin ground sections with Precise 1 System. In the specimens of all groups, there were active odontoblasts near the composite resins and no newly formed dentin. Small quantities of inflammatory cells were present. A 1- to 3-microm layer zone of necrosis was present. In conclusion, all materials tested in this study induced similar tissue responses.