Objective: Evaluate histologically and compare the inflammatory pulp response following direct pulp capping of mechanically exposed dogs' teeth with: Ca(OH)2 base Dycal, UltraBlend Plus and TheraCal LC, at different time intervals. Subjects and methods. A total of 54 permanent teeth of six healthy dogs were used. They were randomly divided into three groups (n=18) according to pulp capping material used. Group I: Dycal, Group II: UltraBlend Plus (UBP) and Group III: TheraCal LC. All cavities were restored with Riva LC Resin Modified Glass Ionomer. Each group was subdivided into three subgroups according to storage time (n=6) at time intervals of 1 week, 1 month and 3 months. Control samples (3 teeth) were added representing normal untouched teeth for evaluating histological features of normal pulp. Paraffin sections were prepared stained with H&E then examined under light microscope for histologic evaluation of the inflammatory cell response. Results: Theracal specimens showed the lowest inflammatory score among the three capping materials in one week period followed by UBP and Dycal respectively .The inflammatory score by the end of third month improved for all materials. No inflammation was detected in Theracal specimens by the end of third month. Conclusions: Subsiding of inflammation over the study period is a sign of biological acceptance of the materials used in this investigation. Theracal is superior to Dycal and UBP for pulp capping of mechanically exposed human teeth, it can be used as an effective direct pulp capping material.

Objective: The objective of this study was to evaluate and compare histologically the repair response following direct pulp capping of mechanically exposed dogs' teeth with: Dycal, UltraBlend Plus and TheraCal LC: at different time intervals (1 week, 1 month and 3 months) Materials and methods: A total of 54 permanent teeth of six healthy male mongrel dogs were used, divided into three groups (n=18) according to pulp capping material used. Group I: Dycal, Group II: UltraBlend Plus and Group III: TheraCal LC. All cavities were restored with Riva LC Resine Modified Glass Ionomer. Each group was subdivided into three subgroups according to storage time (n=6). Control samples (3 teeth) were added representing normal untouched teeth. The specimens were fixed, decalcified, processed to paraffin blocks. Serial sections of 5 microns thickness were prepared and stained with H&E then examined under light microscope for histologic examination and were evaluated histologically for pulp tissue organization and reparative tissue formation following scoring system used by Nowicka et al. Results: As regards calcific barrier, all three materials, by the end of third month showed: continuity (score 3) with irregular dentin bridge formation, the morphology showed mostly irregular hard tissue and the tubules were mild in most specimens. Conclusion: Theracal is superior to Dycal and UBP for pulp capping of mechanically exposed human teeth, it can be used as an effective direct pulp capping material. There was no statistically significant difference between the three capping agents by end of third evaluation period as regards calcific barrier and odontoblastic layer.