Evaluation of PH and calcium release of novel calcium-based materials used in vital pulp therapies

The aim of this study is to evaluate and compare the pH values and the calcium release of various pulp capping materials, in vitro. Calcium hydroxide-based materials; Dycal, Ultra-Blend plus and calcium silicate-based materials TheraCal LC, MTA Angelus, Biodentine and were prepared and placed into molds (diameter: 8.0±0.1 mm; thickness: 1.6±0.1 mm) (n=10). Set samples were immersed in the 10 mL of deionized water. On Day 1, 3, 7,14 and, 28 the storage media were collected for measurement of pH and calcium release and refreshed. The measurements of pH were carried out with a pH-meter (pH 2100 series; pH/mV/Ion/°C/°F Meter with RS232 and Recorder output; OAKTON Instruments, Vernon Hills, IL USA) and the amount of calcium release was determined using an Atomic Absorption Spectrophotometer (Zeenit 700 P, Analytik Jena AG, Germany). All the material groups released both hydroxyl and calcium ions over 28 days which decreased gradually. Exceptionally, the Dycal group showed a tendency to increase regarding calcium ion release. The mean pH was found significantly highest in the MTA Angelus and Biodentine groups in short term (Day 1 and 3) (p<0.005); and Dycal and Biodentine groups in long term (Day 28) (p<0.05). Biodentine group showed significantly the highest amount of calcium ion release among all the material groups in Day 1 (p=0.0001); also highest in Day 28 except Dycal group (p<0.05). On Day 28 the least amount of calcium ion release was measured in the Ultra-Blend plus group among all material groups (p=0.0001). There were no statistically significant differences between the mean amount of calcium ions in MTA Angelus, Dycal, and Ultra-Blend plus groups in Day 1; however, on Day 28, the Dycal material group showed significantly higher calcium ion release than the other material groups except Biodentine (p<0.05). As conclusion; both calcium silicate and calcium hydroxide-based materials tested in this in vitro study were found successful in the release of products required for hard tissue formation. Especially Biodentine group released significantly more calcium and hydroxyl ions in short term. In long term; Biodentine still showed statistically significantly the highest pH and calcium release among all material groups; except the Dycal material group. Keywords: TheraCal, MTA Angelus, Biodentine, Calcium release, pH