A century of controversy regarding the benefit or detriment of occlusal contacts on the mediotrusive side

Many opinions have been presented in the literature during the past century regarding so-called mediotrusive/balancing/non-working side contacts. During the first half of this century, most authors advocated the advantage of these contacts (it was more or less the state of the art in prosthetic treatments), while during the last 50 years mediotrusive side contacts/interferences have mostly been regarded as a disturbing factor in the functioning of the mandible. Recently, it has been proposed that mediotrusive side contacts have a protective effect on the temporomandibular joint (TMJ). The aim of this study was to review opinions advocated during the twentieth century regarding the advantages and disadvantages of having contacts on the mediotrusive side during lateral excursions of the mandible. We conclude that, at present, there is no uniform body of scientific evidence supporting a balanced occlusion in favour of a mutually protective occlusion or vice versa. Longitudinal studies based on cohorts with different types of occlusal contacts, estimating the risk among these of developing signs and symptoms of temporomandibular disorders, are generally lacking and could provide valuable knowledge in this field.