Experimental Pulpotomy Simultaneously Using Dentin Chips and Calcium Hydroxide in Permanent Monkey Teeth with Incompletely Formed Apices

Abstract

Vital pulpotomy involves the application of a medicament or dental material to the amputated pulp in an attempt to preserve its vitality. Many materials and medicaments have been used as pulp-capping agents. Calcium hydroxide has been the standard and is generally accepted as a successful pulp-capping agent of choice. A major disadvantage of calcium hydroxide in amputated pulp is that the developmental structures in newly formed dentinal bridge including small holes or defects with degenerated and necrotic tissues are seen. The purpose of this study was to investigate histologically the tissue responses of amputated teeth pulps simultaneously by using dentin chips with calcium hydroxide. The pulp tissues of 42 sound permanent teeth with incompletely formed apices from crab eating (Macaca irus) young adult monkeys were capped with calcium hydroxide, dentin chips, or the former two agents and evaluated at 3, 7, 14, 28 days or 4 to 5 months after vital pulpotomy. Histological analysis was performed in decalcified serial paraffin sections of 6 to 8 μm thickness stained with hematoxylin-eosin, Bielschowsky-Perdrau's silver stain and Gram's stain. The results obtained were as follows. 1. Following calcium hydroxide dressing, an early calcific (dentin) bridge was well produced beneath the necrotic area of pulp and osteodentin with cell inclusions, vascular channels or finely spaced structures developed over 7 days. 2. When dentin chips were applied directly to the amputated pulp tissue, necrosis of adjacent pulp tissue and inflammation of the contiguous tissue seldom or never occurred. At the early stage, dentin particles appeared to be being phagocyted by macrophage-like cells. The proliferation of fibrous granulation tissues with many new blood vessels and calcification around dentin chips (fragments) were observed 14 days after pulpotomy. 3. Four to five months postoperatively, complete dentinal bridging with healthy radicular pulp was observed in the experimental group in whom dentin chips were applied directly to the amputated pulp areas and calcium hydroxide materials were overlaid. In the teeth, it was obviously effective for inducing continued coronal dentin bridge with fewer developmental holes and defects communicated with the coronal and pulpal surface of the dentinal bridge. These results suggested that the application of non-infected clear dentinal chips plug and calcium hydroxide material directly to the exposed pulp had biocompatibility and successfully caused the formation of a new dentin bridge.