Volumetric Assessment of root canal obturation using 3% nano-chitosan versus zinc oxide eugenol (ZOE) and iodoform-calcium hydroxide (Metapex), in primary root canals shaped with rotary versus manual methods: A preliminary in-vitro spiral CT study

Currently, cytotoxic materials are used for pulpectomy obturation in primary teeth (mostly ZOE or iodoform-Ca(OH)2 compounds). This study compared the volumetric quality of a new biocompatible/antimicrobial agent (nano-chitosan) against conventional obturation materials. It also compared rotary and manual systems. This preliminary in-vitro study was performed on 152 intact non-resorbed root canals of primary molars, divided into [rotary (n=78) versus hand-instrumentation (n=74)], and also into [ZOE (n=53), an iodoform-Ca(OH)2 (n=50), and 3% nano-chitosan (n=49)]. Canals were cleaned/shaped using hand- or rotary-files. Canal spaces were measured using spiral CT. Canals were then obturated using the three materials. The percentages of obturation volume (POV) were estimated for the materials. Canal spaces both before obturation and after it were compared statistically between two filing systems, and between 3 obturation materials (α=0.05). Average POVs of materials were 96.54% (ZOE), 97.87% (Metapex), and 74.74% (nano-chitosan, ANOVA P=0.000). POV of chitosan differed from the other two (Tukey P=0.000), but the other two were similar (P=0.896). Average POVs were 91.46% (manual) and 88.51% (rotary, t-test P=0.322). Pre-obturation spaces of canals for different methods were 3.89 mm3 (manual) and 3.26 mm3 (rotary, t-test P=0.013). Two-way ANCOVA showed a significant effect of materials (P=0.000) but not root length (P=0.585) or shaping methods (P=0.362) on POVs. The nano-chitosan showed a considerable success, but it still needs reformulation as it was weaker than the extremely successful commercial competitors. Rotary instrumentation can provide results similar to hand-filing in terms of POV, although they might yield smaller canals.