RADIOGRAPHIC CARIES DIAGNOSIS BY CLINICIAN IN NORWAY AND WESTERN-AUSTRALIA

In connection with continuing education courses in Norway and Western Australia (WA), dealing with caries diagnosis and treatment decisions, pre-tests were conducted. The pre-tests involved 433 dentists in Norw ay (ND), and 62 dentists (WAD) and 108 dental therapists (WAT) in WA, altogether 603 clinicians. Radiographs of 68 approximal surfaces were to be diagnosed and a treatment proposal was requested for each surfac e. ND showed the best overall diagnostic quality measured by the area beneath ROC-curve (P < 0.00001). The frequency of false-positive diagn oses (over-registrations) on sound surfaces varied between 7.1% (ND) a nd 11.9% (WAT) while the frequency of true-positive scores for lesions in the outer half of dentine varied from 57.4% (ND) to 48.1% (WAT). T he mean numbers of restorations suggested by the three groups of clini cians were: ND: 14.3; WAD: 13.0, and WAT: 14.5. None of the difference s was statistically significant. The proportion of sound surfaces prop osed filled varied considerably between the groups, from 4.3% among No rwegian dentists to 10.6% among WAT (P<0.0001). Of the lesions penetra ting the outer half of dentine, the ND group would have restored 34.5% and the Australian clinicians somewhat fewer: WAD 25.6% and WAT 26.5% . The 11.3% of the ND who proposed more than two fillings on sound sur faces were responsible for 51.2% of the total number of filling propos als on sound surfaces. The corresponding numbers in the Australian gro up were 19.4% (WAD) and 33.3% (WAT) who made 73.6% and 75.7% of the re storative proposals on sound surfaces respectively. When the WA clinic ians made a positive caries diagnosis in enamel, they suggested a rest oration in about 10% of the cases on average, the corresponding value was nearly 20% for the Norwegian dentists. When Norwegian dentists dia gnosed a dentine lesion. in about 94% of cases they also suggested ope rative treatment, for the WA clinicians this proportion was about 90%. The WA clinicians seem to have a more wait-and-see approach with rega rd to instituting restorative therapy based on their radiographic inte rpretation. This difference in treatment philosophy may be due to diff erent experiences of caries progression. In WA most drinking water is fluoridated and caries prevalence is much lower than in Norway.