Calcium hydroxide is used as dressing material for both unexposed and exposed to the pulps. This is a strong alkaline mixture with a pH of about 12, causing superficial necrosis about 1.5-2 mm in the area under its placement on the open cellulose. After the initial irritation subcutaneous tissue, pulp produces new collagen and after that bone-as hard tissues. Avoidance extrapulpal blood clot is essential when using calcium hydroxide as dressing, because its presence may hinder pulp healing. It is therefore important to use a gentle equipment, including cutting with high-speed equipment and diamond burs with subsequent irrigation with water or saline in order to achieve hemostasis.
Formation of a hard cloth barrier, although seldom complete, protects mechanical pulp and provides partial protection from bacterial infection. Although it should be noted that the presence of such a barrier is often considered a criterion of success of the treatment does not guarantee a healthy residual pulp.
Unsuccessful outcomes pulpotomies with the help of calcium hydroxide as dressing attributed to a blood clot left between the dressing and wound surface (73).
In vitro laboratory studies have shown that blood and serum substantially lowered the pH of calcium hydroxide and thereby reducing its bactericidal effect (45). The presence of bacteria in combination with a blood clot, therefore, may be an important reason for the failure. Because the blood clot probably serves as a buffer, it also prevents calcium hydroxide to its superficial necrotic effect on pulp tissue. Another reason for refusal may be the wrong preoperative pulp diagnosis. Thus, it was suggested that calcium hydroxide has no other effect, in addition, contributes to the formation of hard tissue barrier and therefore cannot be successfully used on inflamed tissue pulp (73). The last statement, however, is not consistent with recent reports on the relatively high rates of successful treatments using partial pulpoto I believe in cariously exposed slurries (47, 74).
After pulpotomy with calcium hydroxide as dressing, reported success rates vary between 31 and 80% (24, 52, 71, 89). Using the same criteria of diagnostics, the overall success rates were higher when the calcium hydroxide is used as dressing material after partial pulpotomy (78-83%) (35, 74). As can be seen from these studies, it seems that a partial pulpotomy technique is more favorable than the direct coverage of the tooth pulp. From randomized clinical trials comparing the two techniques yet to confirm this assumption...