Effect of spreader and accessory cone size on density of obturation using conventional or mechanical lateral condensation.

A simulated curved root canal in a resin block was enlarged to size 40 and used to compare the depth of accessory cone penetration and weight of obturation occurring with the use of different obturation techniques and spreader-accessory cone combinations. Twelve groups, each consisting of 10 obturations, were created. A conventional lateral condensation technique was used in six groups and a mechanical lateral condensation (MLC) technique was used in six matched groups. The six spreader-accessory cone combinations were either Fine-Medium or Fine nickel-titanium finger spreaders with either Fine, Medium-Fine, or size 25 accessory cones. Seven accessory cones were placed in every obturation. The depth of each accessory cone penetration into the canal was measured. After each obturation the gutta-percha was removed, sectioned, and the resulting mass was weighed. The means for each variable were determined and compared. MLC fills were significantly heavier and had greater depth of penetration on average than conventional lateral condensation. The best combination for heavy fills was MLC, Fine-Medium spreaders, and Fine accessory cones. The greatest mean accessory cone depth occurred with MLC, Fine-Medium spreaders, and size 25 accessory cones.