Article
Practice-based research has its origin back in around 1993,1 when a publication cited the problems – lack of training for practitioners, need for funding because in practice time = money – but also the solutions – get an interested group together, find the funding and get started. The advantages of carrying out research into restoration survival in general dental practice are obvious: practice is the real world, with real patients and real dentists, from varying undergraduate and postgraduate backgrounds, all of whom are trying to make a living from dentistry. Practice-based research has recently come of age, with the establishment of a practice-based research network at the International Association for Dental Research (IADR). But, do restorations placed in practice survive as well as those placed in the more controlled situations in dental hospitals or academic institutions? I took part in a symposium at an IADR meeting in Helsinki recently, at which this was discussed.
The obvious way to find out how long restorations placed in hospital and practice-based studies survive seemed to be to carry out a literature review. However, after analysing over 30 studies, I still had problems determining where some of the studies were actually carried out, and for the ones that I could determine, the research methodology was so heterogeneous that it proved impossible to actually decide what was happening. Answer – contact Professor Stephen Bayne, of the University of Ann Arbor, USA, someone who has carried out extensive work on survival of restorations everywhere!
Visualize a typical restoration survival curve (Figure 1). This represents a wide variety of factors relating to survival – patient factors, dentist factors, location factors (social grouping, water fluoridation, for example), representing, as Bayne wrote,2 ‘…the average performance for a pool of restorations’. However, Bayne considered that, for the survival of restorations in general dental practice, the curve moves to the left, in other words, restoration survival in practice is less good than in the academic hospital studies.2 Why is that? Well, in hospital-based clinical survival studies, there will be inclusion/exclusion criteria often relating to factors such as the patients' willingness to re-attend for the evaluations (meaning that they must be regular attenders), their caries or oral hygiene status. In other words, they will be ideal patients. Do practitioners taking part in restoration survival studies have such a luxury? No – in practice we have to accept the patients who wish to attend our practices (and pay their bills!). There may also be differing criteria with regard to whether a restoration has actually failed and this may depend upon the sharpness of the dentist's probe. In this regard, a BPE probe is perfectly adequate for checking restoration margins. In addition, in private practice, a restoration may be replaced because the practitioner thinks that it is likely to fail and does not want to wait until there is a catastrophic failure. In other words, practice-based studies are the real world. Practice-based studies evaluate effectiveness (how something performs in the real world) whereas hospital-based studies evaluate efficacy (how something performs in the ideal situation). There is no contest in my opinion. General dental practice, the real world, is where studies on restoration survival should be carried out.
Finally, readers may wonder why there are two papers (by Ekstrand and colleagues, and by Paris and Meyer-Lueckel) on a similar topic in the same issue. The two papers were written independently, but, after peer review, were both ready for publication around the same time. I felt that they were complementary to each other, hence their simultaneous publication. I hope that you enjoy their description and discussion of a new technique and the other papers in this issue.