The aim of this study was to evaluate the ability of the indexes DAI and IOTN in predicting the need of orthodontic treatment based in one property: reproducibility. The index DAI was developed in USA in 1989 and can identify 10 occlusal alterations that result, mathematically, in scores, with weights based in its relative importance according with the judgment of laypeople. The IOTN was developed in England also in 1989 and incorporates an aesthetic component AC and a component of dental health DHC. The AC component consists on a scale illustrated with 10 photos which had been divided in bands of degrees in accordance with a hierarchic scale and classifies the patients in degrees of treatment needed. The instruments of collection of the data were: plastic rule of DHC component and an aesthetic visual scale of component AC praised for the IOTN and one periodontal OMS probe praised for DAI. The sample was composite by 60 patients. The results indicated that both indexes were highly reproducible in accordance with Pearson and Spearman coefficients, which were strengthened by t-tests of Student and Wilcoxon, respectively. The correlation results between the examiners had varied between r=0.85 and r=1.00.