1998, pp 57-58
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FLUORIDE 31(1) 1998, pp 57-58 |
International Society for Fluoride Research | Table of Contents |
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REPLY TO CRITIQUE
Thank you for this opportunity to respond to the critique of our article by Bill Wilson (Fluoride 30 (4) 268-269 1997).
Firstly the referee states that "the full study does not support the conclusions in the abstract." The conclusion(s) in the abstract were "that fluoride exposure during the first 12 years of life, which reduced caries in this population, may also protect teeth from wear to some extent". The referee accuses us of publishing the DMFS data of the entire group presumably to enhance (our) pro-F views. These data were objectively included to illustrate that caries in non-fluoridated subjects does increase with age. However owing to lack of availability of water fluoridation or fluoride supplements to subjects over 50 years of age in this region, comparative groups of subjects, over 50 with F were not available for valid tooth wear comparisons. As the DMFS rates of fluoridated subjects, less than 50 years of age, were consistently lower than the non-fluoridated subjects it seems reasonable to conclude that our subjects were experiencing the reduction in decay, as found in other much larger surveys. Likewise our decision to record DMFS for subjects in the age range of 10-14 is entirely defensible as these subjects did or did not have F within the first 12 years of life, presumably as did subjects of older age ranges.
This was not a study of the incidence of dental fluorosis and we do not claim "total absence of dental fluorosis." Overt caries or restored carious lesions and tooth wear were measured grossly by sextant Any attempt to discriminate between white lesions of enamel due either to fluorosis, demineralisation by plaque acids or demineralisation due to extrinsic or intrinsic acid erosion would have been fraught with logistical and reliability problems.
Paradoxically we agree with the "prevailing view that topical rather than systemic fluoride may confer benefit". We did not state we believed topical fluoride from toothpaste had little if any effect. However this is the only study to date that has attempted to address what, if any, effect systemic fluoride has on tooth wear. We conclude it may have an effect and may empirically support the use of fluoride mouthwashes in the prevention of dental erosion. However we also recorded, for the first time, that fluoride does not appear to protect against severe erosion of lower molar occlusal surfaces which is of real concern to practising dentists, This paper was not intended to be a contribution to the fluoride debate but as a contribution to understanding dental erosion and its management.
W G Young
The University of Queensland
Oral Biology and Pathology
Brisbane, Qld 4072, Australia
REJOINDER
Professor Young has not addressed the main point that the age discrepancies, between fluoride and non-fluoride exposed subjects, made the study1 of little value. The other points in his response are easily answered.
1. He implies that there was only one conclusion in the abstract, yet his study title, 1 and his above quotation, clearly imply two: reduced caries and reduced wear.
2. My statement about pro-F views is confirmed by my quotes from the study.
3. The comment about the non-availability of water and supplement F-exposed subjects over the age of 50 years of age seems to have also largely applied to subjects between 35 and 50 years old.
4. The study conclusion states "Prior fluoride exposure in the first 12 years of life appears to confer some resistance to excessive tooth wear . . . in adulthood . . . ". It is invalid to use tooth wear data of the under 12 year olds or even under 16s in this study, for the obvious reason that they had not yet experienced tooth wear as adults.
5. Young states "we do not claim total absence of dental fluorosis". I quote from the full study: "None of the patients was identified as having mottling or dental fluorosis."
6. My critique quoted from the study that the subjects were well aware "of the protective effects of fluoride." Since fluoridated toothpaste dominates the market, it is reasonable to assume that most of the subjects used it. The study claims that subjects obtaining fluoride from water or supplements had less caries and tooth wear. It follows that topical fluoride from toothpaste appears to have had little effect.
7. It is indeed paradoxical that Young agrees "with the prevailing view that topical rather than systemic fluoride may confer benefit." His study introduction stated "There is considerable evidence that fluoride ingestion in the early years of life, when the teeth are developing, results in reduced risk of dental caries … by incorporation in the apatite lattice".
8. Young’s reply above also concludes that fluoride may have a systemic effect on tooth wear and hence "may empirically support the use of fluoridated mouthwashes in the prevention of dental erosion". Young appears to be very confused, since mouthwash effects, if any, will be topical (unless the mouthwashes are going to be drunk, injected or used in suppositories).
9. Albeit not intended, the study in question, because of its subject, is an interesting contribution to the fluoride debate.
10. Young concludes above that "…our subjects were experiencing the reduction in decay, as found in other much larger surveys." The assumption of the efficacy and safety of fluoride is mainly based on the four North American studies of half a century ago, and 128 later studies quoted by Murray and Rugg-Gunn. 2 The late Dr Sutton of Melbourne University is one of the few scholars who reviewed every one of these studies which were still available. His book, 3 with the critiques, responses from authors, and refutations of the responses, should be required reading for all who still so unquestioningly claim that fluoride benefits are proven.
Bill Wilson
118 Forrest Hill Road
North Shore City
Auckland, New Zealand
REFERENCES
| FLUORIDE 31(1) 1998, p 57 - 58 |
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