First, do no harm

20 March, 2014

For for many years we have written and spoken out against some of the destructive excesses of modern, supposedly ‘restorative’ or ‘cosmetic’ dental
practice, one as a concerned Scottish GDP, and the other as a consultant in restorative dentistry.

We had thought that such destructive methods were becoming less prevalent in modern dentistry, but apparently not so. We, therefore, write to challenge
several of the points expressed in a recent article. This peculiar article demonstrated mild upper anterior tooth surface loss with a mild postural class
three adaptive position, which is often found when the loss of upper incisor height has been due to chemical erosion. We disagree strongly that this
picture showed ‘severe wear’ as was stated in that article.

As a general rule in tooth wear assessment, if the crown heights of the upper anterior teeth have been preferentially shortened, but the height of the
lower teeth have not been equivalently affected, experienced clinicians can usually be fairly sure that the upper tooth surface loss has been caused mainly
by chemical erosion. This is because the lower teeth are generally spared from most of the damage caused by the damaging erosive acid fluids, during either extrinsic or intrinsic acid attacks, by the protective action of the tongue.

The tongue lies over the lower teeth during the swallowing of acidic fluids, or during any sort of regurgitation and thereby keeps most of the erosive
acids away from the lower teeth but allowing the damaging acids to attack the top teeth and thereby shortening them so that their height to width ratios
are reduced disproportionately and they then look ‘short and wide’.

In the recently published case report, the heights of the upper anteriors appeared to have been preferentially reduced to the extent of them being about
the same as their width. By way of contrast, the opposing lower teeth still appeared to be a normal shape and have a significantly greater height than
their width – which is usually the case in healthy unworn lower incisor teeth.

This contrast in the opposing dental arches clearly pointed to chemical erosion as being the most likely explanation for this particular case presentation,
because, if the tooth surface loss had been due to physical attrition, then the much smaller lower incisors would have been worn preferentially, or at the
very least equivalently, to match the tooth surface loss apparent at the upper incisors. By way of illustration of this important differential diagnostic
point, two images from a different case, this time actually showing severe preferential tooth surface loss caused by Coca Cola erosion are shown in Figures
1a and 1b.

Sadly, in our view, it is not infrequent to still see this sort of failure of accurate diagnosis of the probable aetiology for shortened upper teeth before
then proceeding as shown in that recent case report with what, in our sincerely held opinion, was an unnecessarily destructive treatment plan involving
multiple ceramic veneered full coverage crowns for this mild wear problem.

Many of these cases appear to us to be sometimes done for rather questionable ‘cosmetic’ benefit or to conform to some unproven, or unscientific, occlusal
belief system sometimes involving articulators of varying complexity being used in order to treat tooth surface loss problems.

Parts of the Hippocratic Oath include: “Firstly, or most importantly, do no harm”, but also exhort that: “Extreme remedies should be reserved for extreme
diseases.” Mild tooth surface loss is not an extreme disease. Elective removal of much residual sound tooth tissue undoubtedly does structural and other
biologic harm, often involving processes that are not benign, not trivial and not reversible.

High speed drills with diamond burs are dental weapons of mass destruction and every seriously destructive preparation of an already worn tooth will
probably shorten its life. Although the ceramic veneered crowns may well look pretty at the start of their life, that aesthetic or biologic picture will
probably look worse in 20 or 30 years time with a poor ‘fall back position’, sadly, for the patient.

We honestly believe that most experienced dentists when treating mild wear would not remove vast amounts of residual sound tooth tissue from their own
daughter’s teeth1, from a colleague’s teeth, nor indeed have it removed voluntarily from their own teeth. There is no articulator

system in the world that can compensate a tooth for hazarding its pulpal health with an elective full coverage crown preparation2, or for the loss of 62-73
per cent of it’s load bearing structure, which has been shown by Edelhof and Sorenson3 to be what happens with full coverage preparations for ceramic
veneered crowns.

We feel strongly that many experienced dentists would recognise that most sane patients would reject the destructive options if those known figures
mentioned above were explained to them in advance, and in writing, in order to obtain their informed consent for the ‘dental destruction’ illustrated in
these case reports, especially given that there were other viable, non destructive options available to them.

For example, instead of this irreversibly damaging porcelain pornography4 some direct composite bonding applied to the upper incisors to lengthen them and
composite additions to the canines to reintroduce canine guidance, would have predictably changed this sort of ‘pseudo class three’ into a class one
occlusion in relatively short order, but without taking any pulpal risks or doing any structural damage to these teeth.

If the colour happened to have been an important issue for the patient then, again in our view, conventional night guard vital bleaching with 10 per cent
carbamide peroxide could have sorted out that perceived colour problem safely and predictably in advance of some non destructive direct resin composite
bonding being done to change the shapes of the teeth.

Such an additive rather than destructive approach can sort out these apparent tooth surface loss problems, probably in a few visits, with minimal biologic
or structural damage being done to the shortened upper teeth.

Direct resin composite bonding would probably have been predictable, because the composite resin material indicated here only needed to be resistant to
further acid attack, the source of which should have been determined prior to treatment. By way of contrast to the destructive philosophy, a different case
with moderate wear is shown in Figure 2a-d (above) being treated with an ‘additive approach’ rather than a ‘subtractive’ one.

In spite of these alternative, biologically sensible approaches being proven5,6,7 and readily available, we are very perturbed to see case reports using an
outdated and grossly destructive full coverage crown approach to these mainly structurally sound upper teeth, to produce a questionable biologic and
‘cosmetic’ result under the guise of using a semi adjustable articulator.

In those cases, the ‘air rotor attack’ did more damage in one visit than many previous, or successive years of wear might have caused, if the erosive acid
attacks had been identified in order to eliminate them.

This sort of aggressively destructive treatment for the apparently mild tooth surface loss was and remains, in our sincerely held opinion, the wrong
treatment from a biologic perspective. We believe that it can result in about 40 more years of structural damage being done by a dental bur in a short
period of time. This was something that we feel can not now be justified ethically, or biologically, given our modern understanding of the longer term
biological costs of damaging worn but mainly sound teeth.

The adaptive class three shown here was probably just that – adaptive – and in our experience this occurs as a result of slow hard tissue loss and the
periodontal ligament mechano-receptors programming the neuro-musculature around the mandible to move the teeth forward more to an edge to edge relationship
in order to improve function.

However, once one opens the anterior vertical dimension with direct resin, or other restorations, the lower teeth usually move back quite soon in to class
one as the condyles move upwards and backwards quite quickly, and then other tooth movements occur to establish a new intercuspal position over time 5,6,7.
Localised increase in anterior vertical dimension is sometimes described as being a ‘Dahl principle’6, but adaptation by dentate patients to increasing
vertical dimension with restorations, was described by Anderson as long ago as 19629.

In our opinion, given the now well documented evidence for these scientifically proven minimally destructive approaches, it is very worrying for the
profession at large and the patients in general to see this sort of old fashioned iatrogenic damage still being published under the guise of using
articulators to optimise the subsequent crown restorations.

This sort of destructive preparation for crowns in wear cases was common in the 1970s8 and 1980s when that was all that was available for us to treat this
sort of problem.

The sort of treatment shown in these articles pre-dated predictable adhesive dentistry, or our understanding of differential diagnosis of causes of tooth
surface loss, and when treating various sorts of problems without further damaging the teeth was rather less well developed than it is now11.

References :

1. Burke FJ, Kelleher MGD. The ‘Daughter Test’ in elective esthetic dentistry. J Esthet Restor Dent. 2009; 21(3) : 143-6

2. Felton D, Madison S, Kanoy E et al. Long term effects of crown preparations on pulp vitality. J Dent Res 1989; 681009: Abstract 1139.

3. Edelhoff D, Sorensen JA.Tooth structure removal associated with various preparation designs for anterior teeth. J Prosthet. Dent. 2002 May;87(5):503-9.

4. Kelleher M. Porcelain pornography. Fac. Dent. J 2011; 2: 134-141

5. Poyser NJ, Briggs PF, Chana HS, et al. The evaluation of direct composite restorations for the worn mandibular anterior dentition – clinical performance
and patient satisfaction. J Oral Rehabil. 2007 May;34(5):361-76.

6. Gulamali AB, Hemmings KW,Tredwin CJ, Petrie A. Survival analysis of composite Dahl restorations provided to manage localised anterior tooth wear
(10-year follow-up). Brit. Dent. J. 2011 Aug 26;211(4):E9. Doi: 10.1038/sj.bdj.2011.683.

7. Al-Khayatt AS, Ray-Chaudhuri A, Poyser et al. J Oral Rehab. 2013 May;40(5):389-401. Doi: 10.1111/joor.12042. Epub 2013 Mar 15. Direct composite
restorations for the worn mandibular anterior dentition: a seven-year follow-up of a prospective randomised controlled split-mouth clinical trial.

8. Shillingburg HT, Hobo S, Whitsett. Fundamentals of Fixed Prosthodontics Quintessence Publishing Co. 1978, pages 67, 111.

9. Anderson DJ Tooth movement in experimental malocclusion Archs. Oral Biol 1962. p.7-16.

10. Burke FJT, Kelleher MGD, Wilson N, Bishop KB (2011). Introducing the concept of pragmatic esthetics with special reference to the treatment of tooth
wear J.Esthet .Restor.Dent.23 (5) 1-17.

11. Kelleher MGD, Bomfin D, Austin RS (2012). Biologically-based restorative management of tooth wear. Int. J. Dent. ID 742509.

About the authors

John Craig, BDS, DGDP(UK), FFGDP, FDS (RCSEd), qualified in 1966 and was a GDP for 40 years, mainly in Falkirk. He had a long involvement with postgraduate

dental education in Scotland and was chair of SDVTC for seven years. As chair of the steering group which set up the FGDP in Scotland and the first
Director of the West of Scotland Division, he was instrumental in laying the foundations of the FGDP in Scotland. He was a member of the BDA Rep Body/Rep
Board for many years, vice-chair of the BDA Executive Board and President of the BDA in 2005. In 2003 he was awarded an FDS (ad Hominem) by the Royal
College of Surgeons of Edinburgh.

Martin Kelleher MSc, FDSRCPS, FDSRCS is a consultant in restorative dentistry at King’s College London Dental Institute. He has lectured nationally and
internationally on a large variety of topics and is a past president of the British Society for Restorative Dentistry as well as serving on the board of
Dental Protection Ltd for 10 years. He is on the GDC specialist lists in restorative dentistry and prosthodontics and is the author or co-author of many
peer reviewed papers, a number of chapters in books, and some controversial opinion articles. He is in private restorative practice in Bromley, Kent

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