Abstract
This study evaluated physiochemical proprieties of a calcium hydroxide-based paste (Calen®) combined with a zinc oxide cement at different ratios (1:0.5, 1:0.65, 1:0.8 and 1:1). Materials were compared regarding setting time, pH variation, radiopacity, solubility, dimensional changes, flow and release of chemical elements. Data were analyzed statistically by ANOVA and Tukey's test (α=0.05). Longer setting time and higher dimensional changes and solubility values were exhibited by 1:0.65 and 1:0.5 ratios (p<0.05). The 1:0.5 and 1:0.65 ratios exhibited the highest pH values at all time points. All materials exhibited high radiopacity values. Significant differences were found only between 1:0.5 and 1:1 ratios for calcium and zinc release (p<0.05), whereas the amount of zirconium was similar among all groups (p>0.05). Considering the evaluated proprieties, combinations of Calen® paste with ZO at 1:0.5 and 1:0.65 ratios had the best results as root canal filling materials for use in primary teeth.
Highlights
Root canal filling materials used in primary teeth must have compatibility with the apical and periapical tissues, stimulating or enabling repair by means of the deposition of mineralized cementoid tissue or fibrous connective tissue; be placed in and removed from the canals, if necessary; exhibit antimicrobial activity; be radiopaque; adhere to the canal walls without suffering shrinkage; not be soluble in water; not cause tooth discoloration; not set as a compact mass that could interfere with the eruption of permanent successor teeth; be phagocytized together with the physiological resorption of deciduous tooth roots, as well as when they spill accidentally [1]
Among the filling materials used for primary teeth, one of frequently used are materials based on zinc oxide and eugenol [2,3]
Thickening Calen® paste with zinc oxide (ZO) has been suggested to enable the paste’s use as a filling material for root canals in primary teeth [15,18] by reducing its phagocytosis, the speed of which, from a clinical perspective, must be the same as the that of deciduous tooth root resorption, and by improving its physical and chemical properties, such as better working consistency and radiopacity [15], resorption of material synchronously with the physiological root resorption [19], and in vivo biocompatibility [14]
Summary
Root canal filling materials used in primary teeth must have compatibility with the apical and periapical tissues, stimulating or enabling repair by means of the deposition of mineralized cementoid tissue or fibrous connective tissue; be placed in and removed from the canals, if necessary; exhibit antimicrobial activity; be radiopaque; adhere to the canal walls without suffering shrinkage; not be soluble in water; not cause tooth discoloration; not set as a compact mass that could interfere with the eruption of permanent successor teeth; be phagocytized together with the physiological resorption of deciduous tooth roots, as well as when they spill accidentally [1]. Among the filling materials used for primary teeth, one of frequently used are materials based on zinc oxide and eugenol [2,3] They can trigger chronic inflammatory reactions in the periapical tissues [3,4], they alter various cell functions like viability [5], proliferation, and adhesion [6] of cells; they induce the expression of pro-inflammatory cytokines [7]; they alter the process of phagocytosis [8]; they alter the function of neutrophils [9]; they act as inhibitors of cell respiration [10]. Zinc oxide and eugenol (ZOE) can alter the permanent tooth eruption path [12], and they exhibit high apical marginal infiltration [13]
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