424 Examination of occlusion Presentation Transcript
Facial form analysis
Mixed dention analysis
Occlusal wear trauma
Examination of the edentulous and partially edentulous mouth
The examination should begin with a complete history and an evaluation of the patient’s past & present systemic diseases
There is a close relationshipe between the development of occlusion and the development of the face .
When a facial disharmony is present,it does not necessary follow that there will be disturbance in the development of the occlusion .
An analysis of facial form will serve to appraise the harmony of growth and development of the facial skeleton as it relates to support of the dentition .
A -The examin ation should show the presence or absence of abnormal anteroposterior relationships and asymmetries of the dentofacial parts.
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.
Four points of reference may be used to evauate changes in the anteroposterior relationship of of the parts
Making up the facial profile .
1- subspinal (midfacial region) ;
The ala of the nose meets the cheek
2- the prostheon for the maxillary alveolar region
3- the infradental for the mandibular alveolar region
-deepest point of the mentolabial sulcus.
4- pogonion ; (chain point )
Displacement of the mandible may be :-
Skeletal , dental or fuunctional
Retrognathism ;positive posterior displacement of chin point
Prognathism ; an anterior displacement of chin point
The points of reference should be observed when the mandible is in :-
1 -rest position 2 - centric relation 3 - the teeth are in complet occlusion
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
Asymmetries of the frontal facial form are best considered relative the midsagital plane
Systematic comparison of definite areas should be carried out:-Frontal bones, orbital regions,malar regions,maxillary region & mandibular region .
The typical adenoid facies is characterized by thin face,pinched nose,high arched palate& often retrognathia
The typical mouth breather shows a short
upper lip and a lower lip that rests between the maxillary and the mandibular incisors.
Hatched face,flat face,mouse face,dish face,are obvoius indications for an analysis of the facial form
In children 8-12 years of age
The angle made by the base of the mandible and the ascending ramus should be an obtuse angle of about 140 degrees
1- the primary dentition
2- The mixed dentition
3- The occlusion of the permanent teeth in young adult
4- The changes in occlusion that result from wear
3 -5 year
More stable, ovoid arch
Fewer anomalies than either the mixed or permanent dentitions
It does show a wide range of normal variation
No essential change in the occlusion
Growth in the height of alveolar process sagital to the dentition
Spacing of the anterior teeth mesial to the maxillary cuspids & distal to the mandibular cuspids
The length of the arch, from the distal surface of the second primary molar around to the distal surface of the opposite second primary molar , decrease after the eruption of the second primary molars
This decrease continues untile the completion of the primary dentition and.It is caused by the mesial migration of (E)
The primary dentition is characterized by a straight axial inclination of the incisors with an
almost edge to edge relationship of these teeth
The mandibular teeth occlude one cusp anteriorary to the corresponding tooth in the maxilla .
Deviations from this pattern are suggestive of malocclusion .
1-Early loss of primary teeth 2-Prolonged retention of the primary teeth 3-Oral habits ( sucking)
Where the anterior relationship is normal ,an open-bite of this type may be self - correcting ,provided that the child ceases his sever sucking habit by the age of 4 years
The first permanent molar erupt at 6-7 y.
Crowded & rotated position
Tooth eruption has preceded the growth of the jaw ( dental age exceeds skeletal age)
The crowding may be self-correcting because vertical growth of the alveolar processes up to the age of 9-10 years.
Eruption of permanent teeth(choronology.)
Prediction of malocclusion based on :-
sequence of eruption without a consideration of such factors as endocrine disturbance ,familial
tendencies, density of bone,scare tissue ,and
keratinization of the epithelium may lead to malocclusion
Crowded,permenent incisors erupt lingually to decideus teeth, Diastema – leeway space
Etiologic factors that can contribute to a loss of space :-
1-the premature loss of primary teeth
2-retention of primary teeth
3-congenital absence of teeth
4- dental anomlies
5- ectopic eruption
6- abnormal diastema
A harmonious balance between the oral and facial musculature and the teeth are very important .
Contributes to :-
1- facial asymmetry
3- disturbances in the teeth & supporting structures(malposed teeth,cross-bite,faulty restorations,)
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
1- Complete case history
2- Mastictory system (joints,muscles,psychic factors,fatigue,anaxiety,pain )
3- Radiographic examination of the teeth and periodontal structure&TMJ
4-Analysis of the occlusion with an articulator
A diagnosis of occlusal trauma must be made on the basis of an analysis of the occlusion during empty movement ( such as lateral movements with the teeth in light contact )
Palpation,(abnormal tooth mobility, radiographs)
Clinically,(occlusal habits,malocclusion,loss of teeth&periodontal support, faulty restorations,bridges,p.dentures,occlusal interferrnces,cleching,bruxism
Increased tooth mobility
Migration of teeth
Pain ( TMJ,pulpal,atypical,facial,periodontal )
Atypical occlusal wear
Pain in and around the joints Restriction of mandibular movements Tenderness of masticatiory muscles Clicking noises in the joints
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
non-functional grinding of the teeth is an important predisposing factor in occlusal trauma and dysfunctional disturbances of the TMJ.
1- nonfunctional facets of occlusal wear
2- tenderness of masticatory muscles
3- increased muscle tone & spasms
4- hypertrophy of masticatory muscles
5-TMJ stiffness and pain
6- increased mobility of teeth
1-remove the cause
3- elemination of premature contact
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 .