Journal of Indian Society of Pedodontics and Preventive Dentistry
Journal of Indian Society of Pedodontics and Preventive Dentistry
                                                   Official journal of the Indian Society of Pedodontics and Preventive Dentistry                           
Year : 2006  |  Volume : 24  |  Issue : 3  |  Page : 144--145

An in vitro evaluation of pH variations in calcium hydroxide liners


P Subramaniam, S Konde, P Prashanth 
 Department of Pedodontics and Preventive Dentistry, The Oxford Dental College, Hospital and Research Centre, Bangalore, Karnataka, India

Correspondence Address:
P Subramaniam
Department of Pedodontics and Preventive Dentistry, Oxford Dental College, Hospital and Research Center, 10th Mile, Hosur Road, Bommanahalli, Bangalore - 560 068, Karnataka
India

Abstract

The purpose of this present study was to determine the pH changes of five different commercially available calcium hydroxide liners and variations of pH at different time intervals. The following commercially available materials were investigated: Dycal (LD Caulk); Calcimol (Vocco Products); calcium hydroxide powder (Deepti Products); Calcimol LC (Vocco Products); Lime-Lite (Pulpdent Corporation). Five samples were prepared from each liner. The pH measurements were recorded at time intervals of 1 h, 24 h, 3 days and 7 days after mixing of the liner. The pH variations of each material at the given time intervals were recorded and the means were calculated. Comparison of the mean values at all time intervals with the statistical analysis showed significantly high differences ( P < 0.001) between pH values induced by each material at all time intervals. Among the water-insoluble products, Dycal had the strongest alkaline effect after 7 days interval. The materials that chemically hardened produced higher pH values than materials that hardened by a visible light source after 7 days.



How to cite this article:
Subramaniam P, Konde S, Prashanth P. An in vitro evaluation of pH variations in calcium hydroxide liners.J Indian Soc Pedod Prev Dent 2006;24:144-145


How to cite this URL:
Subramaniam P, Konde S, Prashanth P. An in vitro evaluation of pH variations in calcium hydroxide liners. J Indian Soc Pedod Prev Dent [serial online] 2006 [cited 2022 Dec 4 ];24:144-145
Available from: http://www.jisppd.com/text.asp?2006/24/3/144/27895


Full Text

 Introduction



Cavity liner is defined as a liquid in which calcium hydroxide is suspended in solution of natural or synthetic resins.[1] The main purpose of cavity liners is to use the beneficial effects of calcium hydroxide in accelerating the formation of reparative dentin and the high pH resulting in unfavorable conditions for possible remaining organisms.[2]

A layer of cavity liner is placed on the floor of the cavity to protect the pulp from chemical irritants of the restorative material, sterilization of the remaining soft dentin and also to promote reparative dentin formation by increasing the pH of the underlying dentin. It also reduces the permeability of dentin.[1]

The therapeutic effects of calcium hydroxide liners are dependent on the dissociation of calcium hydroxide into calcium and hydroxide ions. This causes high alkalinity, which would activate adenosine triphosphate activity, which in turn might accelerate the mineralization of hard tissues like dentin and bone. The presence of calcium and hydroxide ions might modify the environmental pH in areas of inflammation to levels favorable for cell division and matrix mineralization.[3],[4]

The purpose of this study was to determine the pH changes of five different commercially available calcium hydroxide liners and variations of pH at different time intervals.

 Materials and Methods



The following commercially available materials were investigated: Dycal (LD Caulk); Calcimol (Vocco Products, Germany); calcium hydroxide powder (Deepti Products, India); Calcimol LC (Vocco Products, Germany); Lime-Lite (Pulpdent Corporation). Each product was mixed in accordance with manufacturer's instructions, allowed to set in plastic moulds (diameter 3.5 mm, height 2 mm) and pressed between two glass microscopic slides. Five samples were prepared from each liner. The samples of Dycal, calcium hydroxide powder and Calcimol materials were allowed to harden chemically at 26C and Calcimol LC and Lime-Lite samples were allowed to harden by means of a visible light curing source (LA 500 Blue Light, Apaza Enterprise) for 40 s. The resultant samples were taken out of the moulds and placed into separate vials, each containing 10 ml de-ionized water (starting pH 7.0). The samples were stored at room temperature (26-27C) and pH measurements were recorded at time intervals of 1 h, 24 h, 3 days and 7 days after mixing of the liner. An Ultrameter Digital pH meter (Myroll Company, USA), which was calibrated with standard buffer solutions and a glass electrode connected to the pH meter (Myroll, USA) were used for the measurements.

Statistical analysis was done using ANOVA and post-hoc of Tukey test for the mean pH values recorded.

 Results



Mean pH values and standard deviations of the test materials are shown in the [Table 1]. Comparison of the mean values at all time intervals with the above analysis showed significantly high differences ( P in vivo situation, there is a continuous exchange of tissue fluids at the medicament interface that will rapidly dilute the effect of the calcium hydroxide pH.[2],[11] Hence, further clinical-based studies are warranted. In the present study, the pH values of calcium hydroxide liners were statistically different at different time intervals. Calcium hydroxide powder showed the highest pH at all intervals. All the calcium hydroxide liners rendered de-ionized water alkaline. The materials that chemically hardened produced higher pH values than materials that hardened by visible light source after 7 days.

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