RESUMO
Forca perforation is one of the unexpected and unwanted accidents while root canal procedures which affects the long term prognosis of the therapy. Different material such as ProRoot MTA and MTA has been suggested to repair these perforations; however, the high price of these material has been troublesome for the patients and made the researchers to look for more suitable substitutions.Considering that Root MTA in comparison with other material is more accessible and suitable in price, the present study has been conducted to compare the bacterial microleakage of these three material [Root MTA, ProRoot MTA, Portland cement] to repair forca perforations. In this experimental invitro study, 60 extracted molars were divided into three experimental groups of Root MTA, ProRoot MTA and Portland cement [18 teeth in each group]. There were also two groups of positive and negative in the study [3 teeth in each]. Following access cavity preparation, cleaning and shaping was done. The crowns and the roots of the teeth were cut and the roots were filled. Then a perforation with the diameter of 1mm in the central part of the pulp chamber of each teeth was made. After repairing the perforations with the three material under study, the teeth were exposed to stafillococus epidermis bacteria and the degree of microleakage in each teeth was evaluated at the end of the first and the fifth week with the use of Cochrane, exact fischer and Chi-squre tests. The microleakage in ProRoot MTA group was: 8.27, in Root MTA group was:8.27 and in the group of Portland cement was:3.33. according to statistical tests there were no significant difference amonge these three groups from the point of microleakage and the time of its occurrence. Considering the lack of any significant difference among the three groups under this study, provided that other characteristics of Root MTA and Portland cement are proven, these two are capable to act as substitutions for ProRoot MTA