SEM evaluation of pulp reaction to different pulp capping materials in dog's teeth

Abstract

Introduction: This investigation evaluates the effects of mineral trioxide aggregate (MTA), calcium hydroxide (CH) and calcium enriched mixture (CEM) as pulp capping materials on dental pulp tissues.

Materials and methods: The experimental procedures were performed on eighteen intact dog canine teeth. The pulps were exposed. Cavities were randomly filled with CEM, MTA, or CH followed by glass ionomer filling. After 2 months, animals were sacrificed, each tooth was sectioned into halves, and the interface between each capping material and pulp tissue was evaluated by scanning electron microscope (SEM) in profile view of the specimens.

Results: Dentinal bridge formation as the most characteristic reaction was resulted from SEM observation in all examined groups. Odontoblast-like cells were formed and create dens collagen network, which was calcified gradually by deposition of calcosphirit structures to form newly dentinal bridge.

Conclusion: Based on the results of this in vivo study, it was concluded that these test materials are able to produce calcified tissue in underlying pulp in the case of being used as a pulp capping agent. Additionally, it appears that CEM has the potential to be used as a direct pulp capping material during vital pulp therapy.

Keywords: Calcium enriched mixture; Calcium hydroxide; MTA; Pulp capping agent; SEM.

Figure 1

Scanning electron micrograph of dentin and pulp border of coronal pulp in control group (bold arrow: predentin layer consist of collagen matrix, normal arrows: odontoblast cell bodies in multilayer and intercellular spaces contain a fine network of reticular fibers, arrow heads: branched odontoblastic processes when entered to dentinal tubules, x900).

Figure 2

Scanning electron micrograph of dentin and pulp border in MTA pulp capped tooth (bold arrow: predentin layer consist of collagen matrix, normal arrows: odontoblast-like cell bodies longer than normal ones, arrow heads: hydroxyappatite crystals in the intercellular space, x1500).

Figure 3

Scanning electron micrograph (SEM) of collagenous fibers of predentin of CH pulp capping (x1500).

Figure 4

SEM of dentin and pulp (left) border in CEM pulp capped tooth. Dentinal bridge was broken obliquely and odontoblastic process exit from broken part and are seen naked (bold arrow: predentin layer consist of collagen matrix, normal arrows: cross section of dentinal tubules, arrow heads: odontoblastic processes when entered to dentinal tubules, x1000)