Optimum bitewing examination recall intervals assessed by computer simulation

Objective To assess the effect of altering bitewing examination recall inte rvals on health gain from dental restorative treatment and to determine opt imum recall intervals under varying clinical conditions. Design A computer simulation of the caries process in posterior approximal tooth surfaces. Th e effect of superimposing restorative treatment, based on diagnoses From bi tewing radiological examinations carried out at differing time intervals, w as incorporated. Input data included caries attack rates, median survival t imes of restorations, and sensitivity (Sn) and specificity (Sp) of treatmen t decision making by a high (A) and a low (B) performing dentist, Participa nts A hypothetical population, initially 14-15 years old. Interventions Cla ss II amalgam restorations. Outcome Health gain in utility based units (UBU s) was assessed relative to interim end point UBUs pertaining under 'do not hing scenarios'. Results One thousand approximal surfaces, designated initi ally as 920 sound, 51 carious and 29 filled were followed in the model over in years. The greatest health gain (39.33 UBUs) was from dentist A (Sn = 0 .23, Sp = 0.99, restoration median survival time = 20 years, caries rate = 4.4% per annum, optimal recall interval between bitewing radiological exami nations = 7 months). The least was from dentist B (Sn = 0.52, Sp = 0.88, me dian survival time = 5 years, caries rare = 0.0% per annum, optimal recall interval between bitewing radiological examinations > 120 months) represent ing a loss of 16.79 UBUs compared with 'do nothing'. Conclusions In the bea t interests of their patients, it would seem that dentists need to exercise considerable caution in making positive decisions to restore approximal to oth surfaces on the basis of bitewing radiographic evidence and that for so me dentists current guidelines for bitewing examination intervals would app ear to he too permissive.