The unpleasant taste may prevent the normal population from using diluted bleach as a mouthwash. A recent pilot study, which has resulted already in two papers (since pooled microbiological samples had been taken, one might expect at least another paper) in the once prestigious Journal of Periodontal Research, might leave scientists even more skeptical. The published RCT does not mention the CONSORT statement. Apparently, no sample size was calculated. Randomization took place and 15 test patients with untreated periodontitis were asked to rinse twice per week with 0.25% sodium hypochlorite while 15 patients were supposed to rinse twice per week with water [sic] for 3 months. At baseline and after 2 weeks, patients received oral hygiene instructions, and pockets were irrigated with either 0.25% sodium hypochlorite or, well, water. The test solution was prepared by the patients, one teaspoonful Chlorox (6% sodium hypochlorite) on one-half glass of water (5 mL on 120 mL).
It is very much concerning that just 12 out of 30 patients (40%) completed the 3-month trial. While awful taste of Chlorox was actually mentioned by two patients who, for that, missed couple of rinses, according to Galvan et al. concerns of delay of proper periodontal treatment and transportation issues were the main reasons for drop outs.
But what is even more disturbing is how the authors analyzed their data. Although Galvan et al. (2014) claim that the subject was the unit for all statistical analyses, Gonzales et al., in an additional analysis of just 7 test and 5 control subjects who completed the 3-month trial write,
“The individual pockets were treated as independent statistical units, based on nonspecific and wide-ranging antimicrobial action of sodium hypochlorite and the observation that pockets with a large range of depths responded positively to the bleach treatment and that residual bleeding on probing sites showed no tendency to cluster in particular patients or around specific teeth.” (Emphasis added.)
Most of spurious evidence of the 1970s and 1980s in periodontics stems from that misconception, be it clinical responses when pockets with different depths were considered independent in a limited number of patients, or observations made in microbiological samples from numerous sites in certain patients. At least since Larry L. Laster’s paper of 1985, periodontists must be aware of inflated p-values and spurious conclusions.
Certain dentists have advised patients to rinse with sodium hypochlorite as an adjunct to daily toothbrushing. There is not so much about it in respective databases. A quick search using search terms
(“sodium hypochlorite”[MeSH Terms] OR (“sodium”[All Fields] AND “hypochlorite”[All Fields]) OR “sodium hypochlorite”[All Fields]) AND ((“mouthwashes”[Pharmacological Action] OR “mouthwashes”[MeSH Terms] OR “mouthwashes”[All Fields] OR “mouthwash”[All Fields]) OR (“mouthwashes”[Pharmacological Action] OR “mouthwashes”[MeSH Terms] OR “mouthwashes”[All Fields] OR (“oral”[All Fields] AND “rinse”[All Fields]) OR “oral rinse”[All Fields]) OR ((“mouth”[MeSH Terms] OR “mouth”[All Fields] OR “oral”[All Fields]) AND (“therapeutic irrigation”[MeSH Terms] OR (“therapeutic”[All Fields] AND “irrigation”[All Fields]) OR “therapeutic irrigation”[All Fields] OR “irrigation”[All Fields]))) AND ((“gingivitis”[MeSH Terms] OR “gingivitis”[All Fields]) OR (“gingival diseases”[MeSH Terms] OR (“gingival”[All Fields] AND “diseases”[All Fields]) OR “gingival diseases”[All Fields] OR (“gingival”[All Fields] AND “disease”[All Fields]) OR “gingival disease”[All Fields]),
yields only six papers of which four are review articles which were not further considered in the analysis below. One article dealt with the adjunct effects of subgingival irrigation of chlorhexidine and sodium hypochlorite on scaling and root planing and was not considered either. The study by De Nardo et al. (2012) refers to a pilot study by Lobene et al. (1972) in which 3% hydrogen peroxide and 0.5% NaOCl were used as a mouthwash in a pulsating irrigating device which was also considered here.