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During the last ten years, there has been considerable discussion by practitioners regarding pulp capping. Traditionally, dental schools have recommended that calcium hydroxide (Dycal, Life etc.) was the best agent for capping exposed pulps. In recent years, Dr. Charles Cox (1993) formerly at the University of Alabama conducted a clinical study using monkeys to re-evaluate this concept.  His findings suggested that calcium hydroxide might not be the agent of choice. Instead, he proposed that the vital pulps exhibited a higher level of vitality if first subjected to phosphoric acid followed by an application of a dentin-bonding agent. In fact, it was suggested that calcium hydroxide be eliminated as an intermediate agent under the restorative material.

            The impetus for his studies was derived from earlier investigations of both Branstromm and himself as well. Both investigators have demonstrated clearly that the inflammation of the pulp could be minimized or even avoided by denying the invasion of microbes into the pulpal chamber. Today this microbe free concept is widely accepted by the majority of the profession.

            Subsequent studies dealing with acid etching and subsequent application of a dentin bonding agent however, have not been in total accord. In fact, the overwhelming majority of them (Gwinnett 1998, Costa 2001, Stanley 2001,etc.) have demonstrated that acid etching of pulpal tissue following by an application of dentin bonding agents is strongly contraindicated. Under most conditions, pulpal response to calcium hydroxide was far superior to that associated with application of phosphoric acid and a dentinal adhesive.

            One of the major concerns to an application of the dentin-bonding agent to pulpal tissue was published by Gwinnett. Specifically, he demonstrated that some of the ingredients of the bonding agent actually diffused into the pulpal chamber as a globule or foreign body. Continued histological evaluations demonstrated that although the non degradable globules were surrounded by macrophages, these foreign bodies could not be absorbed biologically. Instead, they remained in tact. The concern then is that over an extended period of time these monomer globules could eventually end up in some lymph gland.

            More recently, still another recent publication has condemned the use of acid etching and bonding directly to pulpal tissue. The conclusion of this paper stated that calcium hydroxide continues to be the most reliable and clinically successful agent for treating small pulpal exposures. The reference is as follows:

Accorinte MLR, Loguercio AR, Muench A, de Araujo VC. Adverse effects of human pulps after direct pulp capping with the different components from a total-etch, three-step adhesive system. Dent Mater (2005) 21, 599-607.

Significance: All of the bonding agent components as well as composite resins should be avoided for pulp capping. Calcium hydroxide should be the first choice for pulp capping.

            Calcium hydroxide is extremely effective in killing those microbes that are associated with the caries process. Simply by elevating the pH to a level of 10.0 or higher, the dissociated hydroxyl ions dramatically change the physiologic environment normally conducive for sustaining those microorganisms.

            Calcium hydroxide is also the material of choice in conjunction with indirect pulp capping. When it is necessary to retain small masses of caries so as not to cause a pulpal exposure, this agent immediately begins to necrose the residual microbes, thereby arresting the caries process. Incidentally, as related to all other systems such as polycarboxylate cement, glass ionomers or zinc oxide and eugenol, calcium hydroxide is the most effective agent available to the clinician.