Vital Pulp Capping With A Bioactive Resin-based Experimental Material Poster #xxxx C.H. PAMEIJER1, O. Zmener2, G. Kokubu2, S. Alvarez Serrano2, M. Yamauchi2, S. Kokubu2, N. D'Annunzio2 1University of Connecticut, Farmington, CT USA.2University of El Salvador/AOA, Buenos Aires, Argentina Objectives: Attempts at developing materials that predictably can generate calcified bridges in direct vital pulp capping treatment continues with an emphasis on bioactive materials. A recently developed pulp capping material (Activa PC) was evaluated for its ability to form a dentin bridge after pulp exposure. The most recent ANSI/ADA Specification #41 Guidelines for Recommended Standard Practices for Biological Evaluation of Dental Materials was adhered to. Methods: Under general anesthesia Cl V cavities followed by pulp exposures were prepared in all 8 lower incisors of 2 young adult goats. A frank exposure as evidenced by bleeding was followed by hemostatis with sterile saline. Activa PC was passively applied to the pulp and light cured. Vitremer covered the capping material followed by selective etching of the enamel margins, a dentin bonding agent and a flowable resin composite (FlowsRite). MTA as control was used according to the manufacturer’s instructions. After 30 and 70 days the teeth were extracted and processed for histological evaluation. Results: A total of 16 teeth were evaluated, 12 with Activa PC and 4 with MTA. Activa PC: After 30 days 5 of 6 teeth exhibited complete dentin bridge formation with frequent incorporation of dentin chips. Of the 5 teeth, 3 had pulps that were chronically inflamed, 2 exhibited minor inflammation. In one tooth an attempt at bridge formation was seen while the pulp was vital with chronic inflammation. There was no evidence of abscess formation or necrosis. After 70 days all 6 teeth demonstrated bridge formation. Superficial and deep pulpal tissues were normal with a few teeth showing isolated inflammatory cells. Enlarged blood vessels either filled with erythrocytes or empty (washed out during histological processing) was frequently seen. The calcified bridges were dense with frequent dentin chip inclusions but with an absence of tunnel formation. MTA: After 30 days a thin bridge and some inflammation and after 70 days a complete bridge, no inflammation and hyperemia were observed. Conclusions: Activa PC tested in goats generated thicker bridge formation with insignificant adverse histological features compared to MTA. Clinical studies in humans are recommended. RESULTS HISTOLOGY A total of 16 teeth were evaluated, 12 with Activa PC and 4 with MTA. Activa PC: After 30 days 5 of 6 teeth exhibited complete dentin bridge formation with frequent incorporation of dentin chips. Of the 5 teeth, 3 had pulps that were chronically inflamed, 2 exhibited minor inflammation. In one tooth an attempt at bridge formation was seen while the pulp was vital with chronic inflammation. There was no evidence of abscess formation or necrosis. After 70 days all 6 teeth demonstrated bridge formation. Superficial and deep pulpal tissues were normal with a few teeth showing isolated inflammatory cells. Enlarged blood vessels either filled with erythrocytes or empty (washed out during histological processing) was frequently seen. The calcified bridges were dense with frequent dentin chip inclusions but with an absence of tunnel formation. MTA: After 30 days a thin bridge and some inflammation and after 70 days a complete bridge, no inflammation and hyperemia were observed. Representative micrograph of experimental material after 30 days. There is a complete thick dentin bridge (DB) containing encapsulated cells and a large chip of dentin (arrow). The pulp shows some congested blood vessels and scattered inflammatory cells. Odontoblast line the dentin bridge and tertiary dentin (TD) extends into the deeper pulp. D=dentin (H&E Stain. Original magnification X100). MTA - control. After 30 days, a complete, but irregular dentin bridge (DB) can be seen at the exposure site and adjacent to the capping material. (H&E Stain. Original magnification X150). OBJECTIVE A recently developed pulp capping material [Activa PC, a visible light curable composite with patent-pending MCP (modified/methacrylated calcium and phosphate)] was evaluated for its ability to form a dentin bridge after pulp exposure. Recommended Standard Practices for Biological Evaluation of Dental Materials, Document No. 41 (ISO 10991) were followed. 70 D Activa PC A: Composite photomicrograph showing calcified dentin bridge mass with debris inclusions and a large dentin chip surrounded by a continuous odontoblast palisade. Note numerous congested vessels and normal tertiary dentin along the canal walls.(H&E stain. Original magnification x45) MATERIALS AND METHODS Under general anesthesia Cl V cavities followed by pulp exposures were prepared in all 8 lower incisors of 2 young adult goats. A frank exposure as evidenced by bleeding was followed by hemostasis with sterile saline. Activa PC was passively applied to the pulp and light cured. Vitremer covered the capping material followed by selective etching of the enamel margins, a dentin bonding agent and a flowable resin composite (FlowsRite). MTA as control was used according to the manufacturer’s instructions. After 30 and 70 days the teeth were extracted and processed for histological evaluation. 70 D Activa PC Photomicrograph showing calcified dentin bridge with debris inclusions..(H&E stain. Original magnification x45) 70 D MTA-control A calcified wall to wall dentin bridge with dentin chip inclusions. Normal tertiary dentin along the canal walls.(H&E staining. Original magnification 100X) CONCLUSION Activa PC tested in goats generated thicker bridge formation with insignificant adverse histological features compared to MTA. Clinical studies in humans are recommended. REFERENCE Recommended Standard Practices for Biological Evaluation of Dental Materials, Document No. 41 (ISO 7405). Supported in part by Pulpdent Corp.