Therefore, bacteria are expected to remain in the great majority of treated canals, and successful treatment is expected when maximum U0126 in vivo bacterial reduction is achieved and the remaining bacteria are in levels that are compatible with tissue healing.25 However, the possibility exists that the host response can be influenced by disease modifiers and, as a consequence, cases with low numbers of residual bacteria might not heal or might take

longer to remit in patients with some unfavorable disease modifier, in spite of adequate root canal treatment. Although herpesvirus infection might be included in this category of disease modifier influencing the response of apical periodontitis

to treatment, this was not observed in the present study for any of the target herpesviruses. Whereas HSV-1/2 was not found in any of the samples, all of the other 4 herpesviruses were detected in saliva from both success and failure groups. Prevalences for these 4 viruses were slightly higher in failure cases, but not enough to reach statistical significance. Therefore, no association of herpesvirus carriage in saliva with poor treatment outcome was discernible in the population studied. One important limitation of this study is that although the PF-02341066 mw evaluation of treatment outcome was retrospective, analysis of virus presence was cross sectional, as this information was available only at the time of recall. Because saliva samples were taken at the time of follow-up examination, it is not possible to infer when infected individuals acquired the virus. Also, the virus presence in saliva may have been only transient after a recent transfer from another infected individual, Adenosine triphosphate which would then represent a carriage state with no infection. For the hypothesis of this study to be confirmed and virus infection be considered a predictor of poor outcome or delayed healing response, the individual should have been infected before the endodontic treatment

or shortly thereafter. However, this study was just a preliminary cross-sectional analysis searching for association. Longitudinal studies are required to confirm or refute the present findings. Samples were collected from saliva for 2 reasons. First, although failure cases might have been treated by surgery and virus detection ascertained directly using the lesion as a source of DNA, this would not be possible and ethically viable for healed/healing cases. Second, had any association with poor outcome been disclosed for the test viruses, development of a test to predict the treatment outcome would be easier because saliva is promptly available and no invasive technique is required for sampling.