Laterognathia Flashcards
(21 cards)
Laterognathia
Buccolingual (transverse) relationship discrepancies
- Misalignment of upper and lower teeth and jaws=>
- Lateral displacement of mandible
- Manifests as laterodeviation or laterognathia
Laterognathia
Difference between laterodeviation and laterognathia
- Laterodeviation=>
- Lateral shift of mandible when closing from rest position into maximum interdigitation
- Often due to occlusal interferences
- Laterognathia=>
- Laterally displaced mandible during initial and maximum opening, and closing from rest position into centric occlusion
- Underlying skeletal asymmetry or TMJ (temporomandibular joint) dysfunction
Laterognathia
Classifications of facial asymmetries
- Dental asymmetries=>
- Midline deviation, unilateral posterior crossbite, arch form deviation
- Skeletal asymmetries=>
- Asymmetries of chin, mandible, maxilla
- Muscular and soft tissue asymmetries=>
- Muscle mass or soft tissue deviations
- Functional asymmetries=>
- Functional shifts of mandible during movement
Laterognathia
Common types of dental asymmetries
- Midline deviation
- Unilateral posterior crossbite
- Unilateral impacted or missing teeth
- Unilateral mesial movement of posterior teeth
- Frontal dental cants
Laterognathia
Possible causes of skeletal asymmetry
- Infections, trauma, fractures, cysts, and tumors
- Fibro-osseous lesions=>hemi-hyperplasia, hemi-hypoplasia, hemi-atrophy, and ankylosis
- Variations in growth affecting chin, mandible, maxilla, and cranial base
Laterognathia
Difference between qualitative and quantitative asymmetries
- Quantitative Asymmetries=>
- Differences in number, such as number of teeth or bone segments
- Qualitative Asymmetries=>
- Differences in size or form=>
- One side being larger or more developed than other
Laterognathia
Pathogenesis of laterognathia and laterodeviation
- Laterognathia=>
- Unilateral deficient or excessive growth of mandible,
- TMJ injuries
- Condylar process agenesis, or conditions affecting cranial base development
- Laterodeviation=>
- Functional shifts due to occlusal interferences
- Unilateral mastication
- TMJ dysfunction, and muscle hypertrophy
Laterognathia
How diagnosis of facial asymmetry established
- History taking=>
- Evaluating trauma, arthritis, or progressive changes in occlusion
- Clinical examination=>
- Assessing dental midlines, vertical and transverse occlusal relationships and skeletal symmetry
- Radiographic examination=>
- Lateral cephalograms, panoramic radiographs, PA cephalograms, and 3D imaging
- Photographic and videographic analysis=>
- Analyzing facial proportions and symmetry
Laterognathia
How evaluation of dental midlines performed
- Done w/ mouth=>
- Open
- In centric relation
- At initial contact
- In centric occlusion
Laterognathia
Facial levels evaluated in facial asymmetry analysis
- Upper canine level
- Lower canine level
- Chin and jaw level
Laterognathia
Radiographic examinations commonly used in diagnosing facial asymmetries
- Lateral cephalogram=>
- Information on asymmetries in ramal height, mandibular length, and gonial angle
- Panoramic radiograph=>
- Gross pathologic conditions, missing/supernumerary teeth, and mandibular ramus/condyle shapes
- PA (posteroanterior) cephalogram=>
- Qualitative and quantitative evaluation of upper facial and orbital regions
- Submento-vertex view=>
- Useful for detailed evaluation of cranial base and mandible
- 3D cephalogram=>
- 3-dimensional view of facial structures
Laterognathia
How to differentiate between laterognathia and laterodeviation
- Clinical tests=>
- Laterognathia: lateral displacement of mandible remains constant during both opening and closing
- Laterodeviation: Facial symmetry reestablished upon opening, but asymmetry returns upon closing into maximum interdigitation
Laterognathia
Prophylactic measures for preventing laterodeviation
- Overcoming oral habits
- Grinding tips of primary canines
- Using space maintainers to restore occlusal and functional oral equilibrium
Laterognathia
Three stages of treatment for laterognathia
- Preadolescent children
- Adolescents
- Adults
Laterognathia
Treatment options for dental asymmetry
- Asymmetric extraction sequences
- Asymmetric mechanics=>different elastic forces on each side
- Unilateral headgear (HG) or Jasper jumpers
- Restorative methods=>composite build-ups or prosthodontic restoration for pronounced asymmetries
- Rapid maxillary expansion (RME) or distalization appliances for arch coordination
Laterognathia
Treatment approach for functional asymmetries
- Minor occlusal adjustments=>mild deviations
- Orthodontic treatment=>aligning teeth and obtaining proper function
- Occlusal splints=>evaluating functional shifts by deprogramming musculature
- Rapid maxillary expansion, orthognathic surgery, and orthodontic treatment=>where skeletal asymmetry present
Laterognathia
How skeletal asymmetries treated
- Orthopedic appliances in conjunction w/ orthodontics for growing patients
- Surgery combined w/ orthodontics for severe discrepancies
Laterognathia
Role of orthopaedic functional appliances in treatment
- Influence eruption (using bite planes)
- Correct linguofacial muscle balance
- Reposition mandible
-appliances can be used alone or w/ surgery to improve symmetry, restore dental occlusion, expand soft tissues, lengthen mandibular ramus
Laterognathia
When orthodontic camouflage considered as treatment option
- When skeletal deformity very mild and no further changes expected. It involves:
- Correcting transverse cant
- Aligning midline
- Tipping teeth to midline
Laterognathia
Surgical options for correcting skeletal asymmetries
- Distraction osteogenesis
- Maxillary surgeries=>Lefort I osteotomy
- Mandibular surgeries=>BSSO, inferior body osteotomy, genioplasty
- TMJ surgeries
- Autogenous/alloplastic augmentation
- Cosmetic surgeries=>rhinoplasty, genioplasty, and cheiloraphy
Laterognathia
Types of occlusal splints used for treatment
- Repositioning splints (mostly for TMJ dysfunctions)
- Superior repositioning splints=>preferred for regular wear for 2-3 months
- These splints help identify functional interferences due to neuromuscular adaptation
