B- The exam iner should not base his entire evaluation of malocclusion on the relationshipe of the first permanent molars or the relationship of the opposing arches, since the reminder of the face and muscles are often intimiately related to malocclusion
* An appraisal of the profile may be made by use of the Frankfort horizontal ( eye – ear)plane and a plane perpendicular to the Frankfort plane that passess through the nasion, called the anterior facial plane .
* An appraisal of facial symmetry may be made by using the midsagital plane ;this is perpendicular to a plane through the orbital and verticle divides the face and head into two equal parts.
Visual inspection of the space occupied by the nose,upper lip,lower lip & chin while the lips are brought together lightly usually indicates that nasal height constitutes about 43% of vertical height while the region below constitutes 57%.
Proportionate lengths of the body and ramus of the mandible should also be evaluated
Lateral&other abnormal shifts of the mandible ( protrusion) may be observed by the examiner when the patient is requested to occlude the teeth from the rest position of the mandible.
An occlusion that is considered normal at the age of 18 years cannot be considered normal for the same individual at the age of 40 or 50y . Physiologic & pathologic process Mamelons(incisal wear),second molars(increse the width of the alveolar arches)
Extraction, replacement of teeth, attration,extrusion,tipping,migration
It is a systematic examination of the anatomy and function of the masticatory system with special consideration given to functional disturbances and pathologic changes in the periodontium,teeth,joint,and muscles of mastication
Etiologic factors responsible for disharmony of the masticatory system as well as for traumatic TMJ arthritis are :-
discrepancy between centric relation and
centric occlusion,abnormal tonicity of masticatory muscles,local irritation associated with periodontal disease or dental caries,loss of vertical dimention,neurologic disorders,loss of teeth without replacement,bruxism
Examination of the edentulous and partially edentulous mouth
Sharpnes,flatness,height and relation to the opposing arches, nasal spine,zygomatic process of the maxilla,hamulus,mental foramen, buccal vestibule,retromolar area, genial tubercles,mylohyoid line,tongue,floor of the mouth
The main difference lies in the analysis. the analysis of the areas to recive dentures relates to effective impressions for adequate construction of the denture base wheres the analysis of denture bearing areas relates to dentures already in use .