Since 1907, the international community has used Angle's classification to assess the mesio-distal relationships of the dental arches. It is the basis of the diagnosis of malocclusion in the sagittal dimension and indicates or not an orthodontic correction treatment. This work was aimed to inventory the classification methods of malocclusions used today. Indices of treatment need were also presented because they are based on one or more occlusal anomalies to indicate treatment. The classifications were criticized and the contribution of a functional analysis based on the use of the trilogy setting, centering and guiding was detailed. The type of anomalies (skeletal and dental) must be completed by the analysis of the occlusal anomaly of setting (centering or guiding) and of the category of occlusion (functional occlusion, functional malocclusion or pathogenic malocclusion), ie its possible pathogenic impact on orofacial structures. A consensus on the classification of occlusal anomalies is necessary in order to better identify the anomalies and their global repercussions, and to better define the needs for orthodontic treatment.