DENTAL EROSION AND TOOTH WEAR

  • Tooth wear arises from multiple causes but most commonly from physical damage, acidic attack and tooth disease
  • The resultant wear can be considered at multiple scales with each scale presenting unique problems for the accurate quantification of wear
  • At the macro scale – complete arch sets or individual teeth – problems include highly sloped surfaces and complex geometry. Quantitative evaluation of erosion is also very challenging due to complex freeform geometry of teeth, evolutionary nature of dental wear and instability of individual teeth reference to one another. evaluating erosion quantitatively very challenging
  • At the micro/nano scale – Wear analysis has previously relied on artificial datum, however this leads to reduced clinical relevance in the result.
  • TaiCaan Technologies have collaborated with a number of dental schools in the UK and Europe to develop tools and techniques to understand and quantify dental wear and erosion.

INTRODUCTION

Research in the area of tooth wear has expanded over the last decade linked to reports identifying dental erosion and a growing problem particularly among Western populations where diet and longevity present aggravating factors. Tooth wear is widely considered to consist of three main aspects; abrasion and attrition (both manifestations of physical wear) and erosion (chemical dissolution) the third.

The methods used for measuring damage caused by tooth wear are many and varied but the method most often reported is contact profilometry. While this method has proven simple, it is extremely slow and generally limited to 2-dimensional measurements. The physical contact, inherent in this method, presents a high risk of wear itself, thus incorrect measurement of the wear, which is case of erosion may typically be micrometres (x10-6 m) scale.

The accurate and rapid transfer of the dental morphology record between patient and laboratory has been made possible by the advent of the current generation of ultra-high performance dental casting materials. The current gold standard for measurement of dental wear measurement is 3-dimensional optical surface metrology, which provides rapid and precise measurement without the inherent risk of wear.

TaiCaan Technologies have specialised in 3-D optical profiling solutions and over the last decade have worked with leading dental research organisations to provide an array of instrumentation, tools and techniques for advanced research into dental wear.

Measuring of Dental Impressions - Macro Scale In-vivo Wear

A typically measurement system employed for investigation of in-vivo tooth wear at the macro-scale may be based around the XYris 2000 system. Featuring a 100 mm x 100 mm motion systems capable of simultaneously mounting multiple full dental arch casts, with the measurement of the entirety of the tooth to the cervical margin made possible through the use of multiple triangulation laser sensors that provide and extremely high angular tolerance and sub-micrometre positional resolution.

The imaging on the right is from the automated measurement and combination of multiple tooth measurements combined into single overview measurement of the complete dental arch. The processing software allows the operator to simply set up the instrument, and return upon completion of the automated measurement.

MORPHOLOGY DATA FROM AN INDIVIDUAL TOOTH AND THE ENTIRE DENTAL ARCH MEASURED WITH THE TAICAAN XYRIS 2000 TL NON-CONTACT 3D OPTICAL PROFILING SYSTEM

Measurement of Micro/Nano Scale Wear – In-vitro Wear

As it is not generally practical to expose human to intentionally damaging dental erosion, nor practical to have them available other than brief periods at infrequent periods, the necessity for in-vitro study for the dental research is obvious.

Practical detection of nanoscale wear is limited by resolution of instrumentation, but more usually by the precision with which the reference data (before wear) can be gathered and fitted. Previously published studies have employed techniques that seek to obviate this limitation. The attachment of artificial datums (where foreign material is attached to tooth samples) or define a reference surface, through processes such as mechanical polishing. In either case the unintended outcome is a sample that is not as clinically relevant by introducing significant variation not present in-vivo.

Using a XYris 2000 CL (100mm stages 10nm resolution) a surface map of the sample is prepared. The sample is then masked and a circular region exposed to erosive conditions. After 5 minutes the sample is recovered, rinsed, dried and remeasured. Before and after data sets are superimposed such that the difference in morphology can be observed. Mathematically – hard point clouds iterative approach – don’t get complex. The eroded region can clearly be measured at the center of the image on the right.

Morphology data from a human tooth section exposed to citric acid erosion conditions for 5 minutes, the blue region is exposed and shows 4UM loss of material.
Morphology data from a human tooth section exposed to citric acid erosion conditions for 5 minutes, the blue region is exposed and shows 4UM loss of material
The measurement plate from a typical 100mm x 100mm X, Y Motion System.

Some Journal Publications using the TaiCaan Technology XYris systems.

  1. S. Austin, J.M. Rodriguez, S. Dunne, R. Moazzez, D.W. Bartlett. (2010), The effect of increasing sodium fluoride concentrations on erosion and attrition of enamel and dentine in vitro. Journal of Dentistry. Volume 38 (Issue 10), Pages 782-787.
  2. S Ranjitkar, J M Rodriguez, J A Kaidonis, L C Richards, G C Townsend, D W Bartlett. (2009), The effect of casein phosphopeptide–amorphous calcium phosphate on erosive enamel and dentine wear by toothbrush abrasion. Journal of Dentistry . Volume 37 (Issue 4), Pages 250-254.
  3. Jose M Rodriguez, Richard V Curtis, David W Bartlett . (2009), Surface roughness of impression materials and dental stones scanned by non-contacting laser profilometry. The Academy of Dental Materials. Volume 25 (Issue 4), Pages 500-505.
  4. M. Rodriguez, R.S. Austin, D.W. Bartlett. (2012), In vivo Measurements of Tooth Wear over 12 Months, Caries Research. Volume 46 (Number 1), Pages 9-15.
  5. M. Rodriguez R.S. Austin D.W. Bartlett. (2011), A method to evaluate profilometric tooth wear measurements, Available: http://www.sciencedirect.com/science/article/pii/S0109564111008657.  
  6. Mann, D. Parmar, A. D. Walmsley, S.C. Lea . (2012), Effect of plastic-covered ultrasonic scalers on titanium implant surfaces, Clinical Oral Implants Research. Volume 23 (Issue 1), Pages 76-82.
  7. Darrell Bartolo, Glenn Cassar, Nadin Al-Haj Husain, Mutlu Özcan, and Josette Camilleri, (2016) Effect of polishing procedures and hydrothermal aging on wear characteristics and phase transformation of zirconium dioxide, Journal of Prosthetic Dentistry.
  8. Aude-Marine Paepegaey, Matthew L. Barker, David W. Bartlett, Miten Mistry, Nicola X. West, Nicola Hellin, Louise J. Brown, Philip G. Bellamy, (2013), Measuring enamel erosion: A comparative study of contact profilometry, non-contact profilometry and confocal laser scanning microscopy. Journal of Dental Materials.
  9. M. Formosa, B. Mallia, T. Bull, J. Camilleri, (2012), The microstructure and surface morphology of radiopaque tricalcium silicate cement exposed to different curing conditions, Journal of Dental Materials.