Asymmetry Flashcards
the face is _____ totally symmetrical
totally
severe asymmetric development of the jaws to cause a problem is:
relatively rare
what is one of the most critical aspects in orthodontic diagnosis
a patient’s frontal symmetry evaluation
even the most esthetic faces are associated with:
mild forms of facial asymmetry
the individuals seeking ortho tx are often associated with:
facial asymmetries that may be greater than the acceptable norms
facial asymmetries are _____ prevalent in ortho pts
more
what are the classifications of facial asymmetries
- skeletal asymmetries
- functional asymmetries
- soft tissue asymmetries
what is a type of mandibular deviation
hyperplastic mandible
what is the etiology of mandibular asymmetries
- prenatal causes
- genetic: facial cleft syndromes - unilateral cleft lip- cleft palate
- congenital
- post natal causes
- environmental
what are the congenital causes of mandibular asymmetry
-hemi-facial microsomia
- neurofibromatosis
- birth trauma
- intra- uterine pressure during pregnancy
what are the environmental causes of mandibular asymmetry
- trauma and infection
- muscle dysfunction
- functional deviations
- TMJ derangements
- hemi mandibular hypertrophy
- pathologies
how are asymmetries diagnosed
- medical hx
- clinical exam: intra oral and extra oral exam
- para clinical exam: radiographs, photographic analysis, digital videography, articulated study models
what is evaluated in the extra oral eval
- frontal
- vertical
- sub-mento vertex
- the pupils are assessed for level with the horizon
- if level then use as horizontal reference line- inter pupillary plane
how do you dx hyperplastic ocndyle
CBCT scans
what is examined in intra oral exam
- functional exam: maximal opening, postural rest position, CR-CO discrpepancy, motor and sensory eval
- eval of dental midlines
- unilateral cross bites
- vertical occlusal evaluation
- transverse cant of maxilla
what is centric relation
a musculoskeletal stable position with the condyles forward as far upward as possible, centered transversely and with the articular disc properly interposed
what is centric occlusion and what is another name for it
- maximum intercuspation
- a dental determined position, tooth morphology and position are the primary influences determining the mandibular position and movements. the condylar position is strongly determined by the dental contacts and intercuspation through muscles and ligaments
what is non functional considered
- no Cr-Co shift
- there is a dental or skeletal asymmetry
what is the importance of radiographic exam
taking an accurate radiograph is crucial as the head position is an important factor in radiographic assessment
we can use different radiographs to evaluate asymmetry such as:
- lateral ceph
- panoramic radiograph
- sub mento vertex view
- CBCT
which is the best radiograph for dx
CBCT
lower dental midlines will usually have an effect on:
the occlusion
asymmetric occlusion =
asymmetric mechanics
what is used to correct or improve the developing inbalance
orthopedic appliances and orthodontics
- hybrid functional appliances
- distraction osteogenesis
What is the frontal eval measured in
1/5ths
- inner eyes to inner inner eye
- inner eye to outer eye
- outer eye to outer ear
what is the vertical eval measured in
1/3rds
- forehead to eyebrowns
- eyebrows to base of nose
- base of nose to the inferior tip of the chin
how are asymmetries treated in non growing individuals (adults)
surgical conditions with severe skeletal asymmetries are not able to be corrected by orthodontic camouflage and growth modification so surgical procedures are used to correct the deformities or asymmetries
what are the treatments for adults with asymmetries
- distraction osteogenesis
- surgical osteotomy: maxillary surgerys (Le-fort I), mandibular strageties - bilateral sagittal split osteotomy (BSSO), inferior body osteotomy, genioplasty
what are the treatments for deviations caused by functional shifts
- mild: minor occlusal adjustments
- moderate to severe deviations: orthodontic treatment to align the teeth
what may be indicated in the management of cases where functional shift is the result of skeletal asymmetry
rapid maxillary expansion, orthognathic surgery, orthodontic treatment
what is another name for an occlusal splint
deprogrammers
what are occlusal splints used for
to properly evaluate the presence and extent of the functional shift by eliminating the habitual posturing and deprogramming the musculature
deformities caused by soft tissue imbalance can be treated by:
either augmentation or reduction surgery
augmentations include:
the use of bone grafts and silicone implants to re-contour the desired areas of the face
