Ions Release and pH of Calcium Hydroxide-, Chlorhexidine- and Bioactive Glass-Based Endodontic Medicaments

Abstract

This study evaluated pH and release of calcium, sodium and phosphate ions from different medications in human dentin. Fifty premolars were prepared and randomly divided into groups: (CHX) - 2% chlorhexidine gel; (CHX + CH) - CHX + calcium hydroxide PA; (CH) - CH + propylene glycol 600; (NPBG) - experimental niobium phosphate bioactive glass + distilled water; (BG) - bioactive glass (Bio-Gran) + distilled water. The specimens were immersed in deionized water and the pH variations were measured. The quantification of ions in the solutions was made by inductively coupled plasma - atomic emission spectroscopy (ICP/AES) at 10 min, 24 h, 7, 14, 21 and 30 days. The results were analyzed by ANOVA and Tukey`s test, with a significance level of 5%. CH had the highest level of calcium ions release at 30 days, while CHX and BG released more sodium ions. BG, NPBG and CHX released a higher amount of phosphate ions. The pH of CH was significantly higher compared with the other groups. CH favored the greatest increase of pH and calcium ions release. The bioactive glasses released more sodium and phosphate ions and presented an alkaline pH immediately and after 30 days.

Physicochemical Properties of Silicate Based Biomaterials

“…Also, it showed the mineral enrichment efficacy [33] . This was in consonance with Carvalho et al [34] who reported that bioactive glasses presented an alkaline pH immediately in the first 10 min, and over the course of 7 days tended to neutralize. Also, in the first 10 min, Bioglass released more calcium, but from 24 h on, this release was decreased and ceased on the 14 th day.…”

Evaluation of the physicochemical properties of silicone- and epoxy resin-based root canal sealers

“…The material is mainly composed of sodium oxide, which stimulates the formation of mineralized tissue. 32,33,34,35,36 Calcium and sodium ion release increases the pH of the dental environment and prohibits bacterial viability.…”

Dentin Microhardness and Sealer Bond Strength to Root Dentin are Affected by Using Bioactive Glasses as Intracanal Medication

“…The different mechanism of ions release between Ca(OH) 2 and bioactive glasses can support the current results where we found a higher dentinal MH when bioactive glasses were in contact with dentin. In a previous study [23], it was shown that NbG and 45S5 release calcium ions, decreasing the amount over time (0 to 14 days), similarly to what occurs with Ca(OH) 2 . If we considered this fact alone, we should expect a reduction in dentinal MH for samples treated with bioactive glasses, in the same manner than that occurred for the samples treated with Ca(OH) 2 .…”

“…We obtained NbG by the fusion of chemical precursors in an electric furnace, according to previous studies [22,23]. The composition of the NbG was 44 wt% Nb 2 O 5 , 3 wt% P 2 O 5 , 21 wt% CaO, and 2 wt% Na 2 O, and 45S5 45 wt% SiO 2 , 24.5 wt% CaO, 24.5 wt% Na 2 O, and 6 wt% P 2 O 5 .…”