Microleakage along apical root fillings and cemented posts

Statement of problem. Coronal leakage of endodontically treated teeth has been found to result in a high failure rate. Purpose. This study tested leakage along apical root fillings remaining after post space preparation and cemented posts in root canals. Material and methods. A total of 120 human roots were used in the study and divided into six groups, 20 roots for each group. By using a modified fluid transport model, leakage (in μL/hr) along ParaPost dowels that were cemented in the coronal 7 mm of root canals with Fuji Duet, Ketac Cem, Panavia EX, or zinc phosphate cements was compared with that along the coronal 7 mm of conventional root canal fillings. Leakage along the apical 4 mm of root filling remaining after post space preparation was compared with that along the 11 mm root filling before post space preparation. Results. More leakage was recorded along the apical 4 mm of root filling than along the 11 mm of original root filling ( p = 0.0325). ParaPost dowels cemented with any test cement did not produce more leakage than the 7 mm coronal root filling ( p = 0.2145). Conclusions. The apical 4 mm of root canal filling remaining after post space preparation leaks statistically significantly more than the original full-length root canal filling. The leakage created by removal of the coronal part of root canal filling during post space preparation may be compensated by the cemented posts. (J Prosthet Dent 1998;79:264-9)