Reactionary and reparative dentin formation after pulp capping: Hydrogel vs. Dycal

Abstract

Background: After indirect capping, injured odontoblasts generate reactionary dentin, whereas after direct capping of a pulp exposure pulp, cells stimulate the formation of reparative dentin. The aim of this study was to evaluate and compare the effects of two direct capping agents on pulp tissue reactions: Hydrogel (a bovine serum albumin (BSA)/glutaraldehyde,) and Dycal (a calcium hydroxide-based capping agent). Methods: In 6-week-old male Sprague-Dawley rats, occlusal cavities were drilled in the first maxillary molars, and the pulps were exposed. In one of the groups, 24 right molars were capped with Hydrogel (G1), whereas in the other group 24 M were capped with Dycal (G2). After 1 to 4 weeks, the rats were anaesthetized intraperitoneally (six rats per group) and perfused intracardiacally with 4 % paraformaldehyde fixative. Maxillary molar's blocks were demineralized with a 4.13 % EDTA solution, embedded in paraffin, and the sections were histologically stained. Measurements of the thickness of reactionary dentin and area of inflammation were measured with ImageJ software. Results were compared with Kruskal Wallis and Mann Whitney U tests at p = 0.05. Results: One week after Dycal capping, a statistically significant large number of aggregates of pulp cells enlightened pulpal inflammation compared to Hydrogel. At 2-3 weeks, reactionary dentin formation was increased at the periphery of the pulp chamber. After 4 weeks, a dentinal bridge sealed partially the pulp exposure, while tunnel defects persisting across reparative osteodentin. In contrast, 1 week after Hydrogel capping, inflammation was barely detectable. Hydrogel induced the massive apposition of reactionary dentin at the pulp periphery, and reparative dentin was developing within the pulp. The degradation of Hydrogel releases glutaraldehyde acting on pulp cells as a fixative and consequently favoring BSA bioactivity. Conclusion: After Hydrogel capping, nemosis stimulates pulp mineralization, improving reactionary and reparative dentin formation. In contrast, the highly alkaline compound Dycal produced inflammation within the pulp. The differences between the two capping agents suggest that Hydrogel might present some clinical advantages over Dycal.

Clinical Comparison of Eggshell Derived Calcium Hydroxyapatite with Dycal® as Indirect Pulp Capping Agents in Primary Molars

“…A Njeh studied the reactionary and reparative dentin formation after pulp capping with Dycal ® . The thickness of reparative dentin varied between 100 and 200 μm (0.1-0.2 mm) after 4 weeks [28]. Whereas, in the present study the reparative dentin thickness formed by eggshell derived calcium hydroxyapatite (0.091 ± 0.003) was much higher than Dycal ® (0.061 ± 0.001) at the end of 3-months review.…”

Pulpal repair after direct pulp capping with new bioceramic materials: A comparative histological study

“…Pulpal floors were further deepened until the unexposed pulp was seen through dentin as a pink spot. The pulp was then exposed in the middle of the pulpal floor using a sterile dental explorer (Hu-Friedy, USA) (Njeh et al, 2016). Bleeding was controlled by placement of a cotton pellet moistened with sterile saline until physiologic hemostasis occurred.…”

Characterization of Chlorhexidine-Loaded Calcium-Hydroxide Microparticles as a Potential Dental Pulp-Capping Material

“…Nevertheless, it can be observed that CHX incorporation has not adversely affected the alkalinity of CHX-loaded/Ca(OH) 2 microparticles as the high pH values were maintained throughout ( Figure 6 a), as indicated in earlier studies [ 18 ]. When performing pulp capping, such high alkalinity of Ca(OH) 2 is known to incite an irritation potential, capable of inducing coagulation necrosis at the contact surface of the pulp [ 68 ]. Accordingly, the high pH values of the CHX-loaded/Ca(OH) 2 microparticles (at 15 days) indicate their promising potential for reparative dentin barrier formation.…”

“…However, experiments involving a vital pulp and corresponding histological evaluation of the dentin-bridge formation will provide fertile ground for future research. Previous literature findings have reported formation of mineralized tissue from ~7th to 10th day upon contact with Ca(OH) 2 , with complete bridge formation in 4 weeks sealing pulp exposure [ 68 , 69 ]. In the present study, in vitro CHX-release profiles show ~94.94% of CHX released in ~15 days ( Figure 9 a) and it is anticipated that the CHX-loaded/Ca(OH) 2 microparticles continue to release CHX in a sustained manner beyond this specified time-period.…”