Inclusion Criteria:  Overjet group:  ANB angle ≥ 3 degrees (ANB are three marking points, which produce an angle describing the skeletal relationship between the maxilla and mandible) Horizontal maxillary overjet ≥ 6 mm and need of orthodontic treatment according to the Danish procedure for screening the child population for malocclusion involving health risk. Informed consent from parent(s)/guardian(s)  Control group:  Neutral occlusion No history of orthodontic treatment Informed consent from parent(s)/guardian(s)  Exclusion Criteria:  Known general and/or craniofacial syndromes/diseases Known sleep disorders, included bruxism during sleep Chronic respiratory diseases and asthma6/12 Adenoid vegetations, hypertrophic tonsils and significantly reduces airflow through the nose (mouth breather), which need primary treatment. Dysfunction of masticatory muscles and temporomandibular joint, which need primary treatment.