Research abstract
British Dental Journal 196, 42 - 45 (2004)
Published online: 10 January 2004 | doi:10.1038/sj.bdj.4810881
The in vivo perception of roughness of restorations
C S Jones1, R W Billington2 & G J Pearson3
- Patients are very aware of rough restorations.
- Little research has been carried out on the degree to which patients can detect differences in roughness.
- This study shows that previous figures for surface roughness values were much too high.
Abstract
Objective To determine a threshold of detection value for surface roughness of restorations by patients using their tongue.
Method Samples of composite resin were finished with differing grades of abrasive. The surface roughness (Ra) was measured and representative scanning electro-micrographs taken. These were compared with labial enamel. Twenty-five volunteers were asked to rank them in order of perceived roughness using the tip of their tongue.
Results These showed that the 60% of volunteers were able to rank the specimens correctly, and were able to distinguish differences in roughness values from between 0.25 and 0.50 
m. This range encompasses that of natural enamel.
Conclusions The subjects were able to distinguish lower roughness values than have previously been reported. It is concluded that when finishing restorations the surface should have a maximum roughness 0.50 m if it is not to be detected by the patient.
- C. S. Jones, Hon. Research Fellow Queen Mary, University of London
- R. W. Billington, Hon. Research Fellow Queen Mary, University of London
- G. J. Pearson, Professor of Biomaterials in Relation to Dentistry, Queen Mary, University of London
Correspondence to: C S Jones1
Biomaterials in Relation to Dentistry, Medical Sciences Building, Queen Mary Westfield Campus, Mile End Road, London E1 4NS
e-mail: cjonesstheaker@cwcom.net