Conflict of interest: non-existentAccording to Grade et al. 2 , the temporomandibular joint (TMJ) represents the connection of the mandible to the base of the skull, which in turn presents muscle and ligament connections with the cervical region. Together, they form a functional system denoted cranio-cervico-mandibular. Studies concerning this intimate connection have been designed in order to confirm that changes of posture of the head and of other body parts may lead to functional alteration of the masticatory system and vice versa [3][4][5][6][7][8] . It has been observed that the molar relation seems to play an important role in this connection and that certain malocclusion problems may be related to changes in head posture more than others 9 . Several authors have studied the presence of changes in head posture in patients with malocclusion. Some of them have stated that patients with class II and class III malocclusion present changes in head posture on the sagittal plane 1,[10][11][12][13] , as well as on the frontal and transverse plane [13][14][15] . Although there is a consensus about the connection existing between the stomatognathic and ABSTRACT Purpose: this study investigates whether there is a difference in head posture between groups with different dentofacial deformities (class II and class III) and a group with no deformity. Method: 25 volunteers aged from 16 to 40 year old took part in the study. Ten patients had a diagnosis of class II dentofacial deformity, 15 had a diagnosis of class III skeletal deformity, and 15 healthy volunteers matched for sex and age to the group with deformity were used as a control group. Head posture was first checked, followed by evaluation through postural photography (photogrammetry). Results: there was no significant difference (p>0.05) between groups regarding postural evaluation by photogrammetry. However, postural evaluation using clinical inspection, revealed anterior head posture among subjects with class II dentofacial deformity compared to subjects with class III deformity (p = 0.001) and to control group (p = 0.001). The percentage of class II dentofacial deformity subjects with neutral head posture was also lower compared to class III dentofacial deformity (p = 0.008) and to control group (p = 0.001). Conclusion: subjects with class II dentofacial deformity may show anteriorization of the head. There is no influence of the deformity on the increase or reduction of the head-neck angle when analyzed by photogrammetry.

OBJETIVO: este estudo investiga a diferença entre grupos com deformidade dentofacial (padrão classe II e classe III), em relação à preferência mastigatória referida e inclinação de cabeça durante a mastigação, assim como predomínio intra-grupo de cada um desses aspectos, comparativamente a um grupo controle. MÉTODOS: participaram deste estudo, voluntariamente, 25 pacientes (entre 18 e 35 anos). Doze pacientes com diagnóstico de deformidade dentofacial classe II e 13 pacientes com o diagnóstico de classe III esquelética e 10 voluntários, com equivalência em sexo e idade ao grupo de deformidade, formando o grupo controle. Os voluntários da pesquisa foram questionados sobre a existência de um lado de preferência mastigatória. Em seguida foram filmados durante a mastigação habitual de um biscoito maizena e através das imagens captadas, a postura de cabeça pôde ser analisada. RESULTADOS: não houve diferença entre os grupos em relação à preferência mastigatória referida, entretanto os grupos com deformidades dentofaciais apresentaram predomínio significativo de preferência mastigatória referida. Os grupos com deformidade dentofacial apresentaram maior predomínio de inclinação de cabeça durante a mastigação quando comparados ao grupo controle. CONCLUSÃO: indivíduos com deformidade dentofacial podem apresentar uma preferência mastigatória e alteração de postura de cabeça durante a mastigação.

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