This allows for an accurate assessment of the size, position, orientation, shape, and symmetry of the jaws. The anterior-posterior skeletal pattern measures the relationship of the lower jaw to the upper jaw. This is judged with the patient seated upright, head in a neutral horizontal position, and teeth in gentle occlusion. It can be classified into the following classes:

Class I: The ideal relationship whereby the upper jaw lies 2-4mm in front of the lower jaw 
Class II: Upper jaw lies more than 4mm in front of the lower jaw
Class III: Upper jaw lies less than 2mm in front of the lower jaw, or in more severe cases, the lower jaw may be in front of the upper jaw. The vertical dimension can be measured by facial thirds, with ideal facial aesthetics showing equality between each vertical third. The face is divided into thirds – hairline to glabella; glabella to subnasale; and subnasale to the lowest part of the chin. Two other clinical indicators can be assessed when analysing vertical dimensions, namely the Frankfort Mandibular Planes Angle (FMPA) and the Lower Facial Height (LFH) – both of which are each recorded as either average, increased, or decreased. FMPA: This is estimated by the point of intersection between the lower border of the mandible and the Frankfort Horizontal plane. LFH: The face is divided into thirds, and the proportion of the lower third of the face is compared to the rest.The transverse relationship is a measure of jaw or facial asymmetry.
There are also studies in mice and dogs reported the protective effect of folic acid supplementation to prevent cleft lip palate occurrence. Treatment
Jaw abnormalities are commonly treated with combined surgical (orthognathic surgery) and orthodontic treatment. The procedure is carried out by oral and maxillofacial surgeons and orthodontists in close collaboration.In most cases, the orthodontist will first align the teeth with braces or other appliances, which may worsen the occlusion until after the surgery. This is carried out to show the full degree of abnormality, and to create sufficient space for full correction in the bones.Orthognathic surgery, also known as corrective jaw surgery, is performed to normalise dentofacial deformity and reposition part/all of the upper and/or lower jaws to improve occlusion stability and facial proportions. It is the mainstay treatment for patients who are too old for growth modification and for dentofacial conditions that are too severe for either surgical or orthodontic camouflage.The surgery usually involves gaining access to the bone from inside the mouth, revealing and moving the bone into a correct functional position, and fixing it in position with metal plates and screws. These plates are most often left in the bone, but at times require removal due to infection, which would require another operation. Most orthognathic surgeries are performed inside the mouth without any external scarring. Mandibular surgery
There are numerous surgical techniques available to correct the position of the mandible.