British Dental Journal 206, 4 (2009)
Published online: 10 January 2009 | doi:10.1038/sj.bdj.2008.1147

Formocresol: a plea

B. B. Lewis1

Send your letters to the Editor, British Dental Journal, 64 Wimpole Street, London W1G 8YS e-mail: bdj@bda.org
Priority will be given to letters less than 500 words long. Authors must sign the letter, which may be edited for reasons of space.

Sir, I write further to my letter published earlier in the year (BDJ 2008; 204: 477) and A. Milne's reply (BDJ 2008; 205: 615).

Having started the debate in 19811 I have had the benefit of reviewing the literature2, 3 as it has developed, without bias and with consistent regard for scientific principles and protocols. Hand-picking studies that have aberrant or inconclusive results when weighed against the accepted evidence becomes self-serving while simultaneously destructive to clinicians seeking the best for their patient.4 As recently as March 20085 research has shown that formocresol causes genetic damage. Studies using the comet assay have previously produced contrary results when examining peripheral lymphocytes.6

Some studies dismiss the addition of cresol without scouring the literature. I am baffled when I read: 'No data currently exist regarding ... environmental sources of cresol' and its inclusion in formocresol is dismissed as unimportant.7 Cresol exposure runs the gamut from photographic materials to cigarette smoke and various forms of cresol have been identified as being mutagenic from the early 1980s onward. Newer research shows its genotoxicity to mammalian cells.8

I urge dentists to rethink their use of formocresol. Children should not be exposed to formocresol since there isn't any conclusive evidence warranting its use.



  1. Lewis B B. Formaldehyde in dentistry: a review of mutagenic and carcinogenic potential. J Am Dent Assoc 1981; 103: 429–434. | PubMed | ChemPort |
  2. Myers D R. Distribution of 14C-formaldehyde after pulpotomy with formocresol. J Am Dent Assoc 1978; 96: 805–813. | PubMed | ChemPort |
  3. Casas M J, Kenny D J, Judd P L, Johnston D H. Do we still need formocresol in paediatric dentistry. J Can Dent Assoc 2005; 71: 749–751. | PubMed |
  4. Milnes A R. Persuasive evidence that formocresol use in pediatric dentistry is safe. J Can Dent Assoc 2006; 72: 247–248. | PubMed |
  5. Ramos M E, Cavalcanti B C, Lotufo L V, de Moraes M O et al. Evaluation of mutagenic effects of formocresol: detection of DNA-protein cross-links and micronucleus in mouse bone marrow. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2008; 105: 398–404. | Article | PubMed |
  6. Ribeiro D A, Marques M E, Salvadori D M. Lack of genotoxicity of formocresol, paramonochlorophenol, and calcium hydroxide on mammalian cells by comet assay. J Endod 2004; 30: 593–596. | Article | PubMed |
  7. Collaborative Study by Anesthesia and Dentistry Confirms Routine Use of Formocresol in Pediatric Dentistry. Practice Update Winter 2007.
  8. Hamaguchi F, Tsutsui T. Assessment of genotoxicity of dental antiseptics: ability of phenol, guaiacol, p-phenolsulfonic acid, sodium hypochlorite, p-chlorophenol, m-cresol or formaldehyde to induce unscheduled DNA synthesis in cultured Syrian hamster embryo cells. Jpn J Pharmacol 2000; 83: 273–276. | Article | PubMed | ChemPort |
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