Ca(OH)2 application modes: in vitro alkalinity and clinical effect on bacteria

Area of Science:

• Endodontics
• Dental materials science

Background:

• Calcium hydroxide (CH) is widely used in endodontics for its antimicrobial properties and ability to maintain an alkaline environment.
• Different formulations of CH exist, including pastes, gels, and combinations with gutta-percha, which may influence their performance.

Purpose of the Study:

• To compare the alkalinity maintenance of five calcium hydroxide (CH) products, including CH-gutta-percha Plus points (CHGP) and conventional CH paste.
• To evaluate the clinical antimicrobial efficacy of CHGP.

Main Methods:

• Laboratory assessment of CH product alkalinity via titration with HCl and in the presence of dentine powder.
• Clinical trial involving 21 teeth with apical periodontitis, medicated with either CHGP or conventional CH paste.
• Bacterial sampling before and after treatment, with statistical analysis using ANOVA and Fisher's exact test.

Main Results:

• Aqueous CH mixtures and Calasept demonstrated the highest alkalinity, while gel products and CHGP showed significantly lower values.
• Dentine powder neutralized all tested CH products to pH 8.6 within 24 hours.
• Clinical trials showed culture-negative results in 5/10 canals for CHGP and 7/11 for conventional CH, with no statistically significant difference.

Conclusions:

• Aqueous CH formulations maintain higher pH compared to viscous gel products and CHGP.
• Dentine powder exhibits a consistent buffering effect across all tested CH products.
• Both CHGP and conventional CH paste possess clinical antimicrobial activity, but without a significant difference in efficacy.