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An alternative regimen for root canal disinfection Bonsor S. J. Nichol R. Reid T. M. S. and Pearson G. J. Br Dent J 2006; 201: 101– 105

Comment

In photo-activated disinfection (PAD) bacteria become photo-sensitised by absorbing a solution of tolonium chloride. The solution is activated by low power laser (635nm) light releasing active oxygen species causing disruption of the bacterial membranes.

This paper describes the application of PAD in endodontics. Patients requiring root canal treatment were divided into two groups. In both, crown-down pressure-less canal preparation was used but with different sequences of irrigant and photo-activated disinfection and the bacterial load was determined at three stages. In Group 1, there was initial coronal preparation using citric acid and sterile water as irrigants, then PAD. In Group 2, citric acid and NaOCl were used together and the canal fully prepared, then PAD was used. The root canals were sampled for aerobic bacteria: the sampling regime is not easy to follow because treatment of the canals was different between groups. The following table may help:

Table 1

The Group 1 results demonstrated the efficacy of PAD in eliminating nearly all aerobic bacteria, where only sufficient coronal canal preparation was made to allow access for the light guide required to activate the photo-sensitising solution. Subsequent full canal preparation led a small further bacterial reduction. In Group 2, conventional p reparation accompanied by citric acid and NaOCl irrigation produced a similar reduction in bacterial load as in Group 1. Further treatment in Group 2 using PAD gave a small additional bacterial reduction. The reduction in bacterial load between the first and second samples was highly significant for both groups.

The results indicate potential for PAD in root canal disinfection of aerobic organisms. The study would have been clearer if sampling procedure 2 had been the same in both groups i.e. the canals initially enlarged coronally, treated with their respective irrigants and Group 1 treated with PAD. The report also hdsints at potential fragility of the light guide on the photo-activation equipment.

The investigator is to be commended for managing within primary care a complex clinical protocol. PAD has potential in root canal disinfection, one of the aims of endodontic treatment. It is hoped that the authors will continue their work.