The use of 0.5% or 3% NaOCl for irrigation during root canal treatment results in similar clinical outcome: A 6-year follow-up of a quasi-randomized clinical trial
Arvid Dahlstrand Rudin, Agnes Dahlstrand Rudin, Charlotte Ulin, Thomas Kvist
Don’t you love it when you can guess the conclusion of a study before you read it!
I’m afraid this kind of predictable and flawed clinical trial is the sort of quasi-science we have to put up with as quasi-scientists.
About 300 patients referred for root canal treatment to an endodontic specialist clinic were recruited to the study. The concentration of NaOCl was allocated quasi-randomised at 50% in each group. Bacterial sampling was performed immediately before root canal filling. Samples were cultured and evaluated as growth or no growth. Patients were invited to a clinical and radiological follow-up more than five years postoperatively. The clinical outcome measurements were tooth survival, cumulative incidence of endodontic retreatments, patients’ assessment of pain, clinical findings and radiological signs of apical periodontitis.
So it reads well to start with. A decent hypothesis and something that would be useful to know. Tick. A clinical trial. Tick. Sort of randomised. Tick. Six years. Tick. Largish sample. Tick.
But hang on. What treatment protocols were used? How much hypochlorite was syringed into the canals? What were the canal preparation sizes? One visit or two visits? Does negative growth on a paper point really mean the canal is bacteria free, or maybe the paper point didn’t reach where the bugs are?
Tooth survival is an adequate level playing field, but would we not want to know the true measure of clinical success with radiographic healing? Sadly, the periapical radiograph is the adjudicator. Well known for missing pathology, issues with comparative assessment with different projections, and with difficulty in inter-observer and intra-observer variation; success/failure studies have moved on to using more definitive CBCT data.
I try not to write off any paper and look for some learning points. The limitations, though, in these sort of well-meaning studies make it almost impossible to derive something. The headline will no doubt be quoted in lectures to the undiscerning. Unsurprisingly, the use of 0.5% or 3% NaOCl for irrigation during root canal treatment resulted in similar clinical outcomes 5-7 years postoperatively. Well I’ll be darned!
And also, persisting bacteria immediately before root filling may predict future episodes of subjective pain. Very useful. I will send paper points taken under CO2 for culture, taking a week, so I can possibly predict whether the patient will get pain immediately after treatment. Why?
International Endodontic Journal. First published: 12 August 2024
https://doi.org/10.1111/iej.14134
