A Relationship Study Between Developmental Lateral Jaw Deformity And Cervical Spine Disorders

Developmental lateral jaw deformity(DLJD) is a common kind of jaw deformity in clinic. Patients suffer from not only craniofacial paramorphia but also oral ~lysfunction. Additionally, recent studies have found that DUD was often accompanied by abnormal cervical curve and pain in head-neck, shoulder and back muscles, which are similar to cervical spine disorder(CSD).Up to now, it is not clear that whether DUD could lead to CSD and by what way it does. Therefore, studies of facial morphology, cervical spine curve and also oral clinical examination were preformed to research the relationship between these two kinds of disease. Furthermore, electromyography and mandibular movement as well as head and shoulders movement were also recorded to research the etiology from craniofacial to cervical diseases. 39 young healthy adults with normal occlusion severed as control group and 28 developmental mandibular lateral deviation persons as patient group. The following studies have been carried out: i.The relationship between developmental lateral jaw deformity and cervical spine disorders. Cephalometric and cervical spine roentgenograms of posterior-anterior, lateral projection in nature head position and radiographs of mental-vertical, lateral temporomandibular joint tomogram were taken for both two groups to exam bone structures and morphology both in craniofacial and cervical vertebrae in order to research the relationship between this two kinds of diseases. 2.The pathogenesis from jaw deformity to cervical spine disorders. Surface electromyographic signals from left and right sides of masseter, anterior digastricus, sternocleidomastoid,upper-trapezius muscles and mandibular movement were detected during self-paced continuous maximum jaw opening-closing, gum chewing, shoulders elevation-lowering, protraction-retraction and head flexion? extension movement. Basing on frequency domain, time domain and Joint Time Frequency, muscular function was analyzed to compare the difference of the four paired muscles and the symmetry in the two groups so as to clarify the etiology from jaw deformity to cervical spine disorders. -4- 3.Treatment methods for patients who suffer from both jaw deformity and cervical spine disorders. Morphological and kinetic changes in patients were compared to find if cervical spine disorders could be relieved by orthodontic correction and (or)orthognathic surgery treatment. The main findings were: The relationship between cranofacial morphology and cervical spine posture. 1.The inclination of the dens and the cervical vertebrae plane showed positive correlation to Frankfort Horizontal, Palatal, Occlusal and Mandibular Plane. Each plane inclination was high in case of forward flexion dens in both control and patient group; 2.The curve from the second cervical vertebrae to the fourth cervical vertebrae had a negative correlation to the cervical vertebrae plane inclination .The curve was small with forward flexion dens but large with backward flexion dens in both two groups. 3.The position of the left and right side molar, mandibular angle and condylar as well as mandible height had significant difference in two groups (P