Limitations and Risks in Orthodontics Flashcards
What are the limitations in Orthodontics
Anatomic
Physiologic
Therapeutic
What are some anatomic limitations of orthodontics
- Skeletal discrepancies - AP, Transverse, Vertical (size)
- Alveolar ridge
- Space
- Soft tissue
What are the treatment options for skeletal discrepancies
Growth modifications (growing patients)
Orthognathic surgery (adults)
What is the advantages of miniscrews
It broadens the maximum envelope of tooth movement
Which can be expanded transversely more? Lower or upper jaw
Upper (mid-palatal suture)
At which arch location is most prone to transverse expansion relapse and why
Intercanine expansion
At the commissure of lips where there is greatest lingual force
How is alveolar ridge an anatomical limitation?
Early extraction creates an alveolar bone defect which causes risk of fenestration/dehiscence/gingival recession
How much can you procline incisors and what happens if you exceed this limit?
2mm
>2mm causes instability
But also dependent on initial position
What happens if you advance incisors (AP) or expand premolars and molars (transversely) too much? How much is too much transverse movement for molars
Risk fenestration/dehiscence/stripping of gingiva
> 3mm
What are some compromises due to anatomical limitations in orthodontics
Health
Aesthetics
Function
Stability
What are examples of compromises in Class II DAC patients
Poor upper lip support
Lower lip protrusion
Lingual relapse of lower incisors (due to forces from lips)
Periodontal risks of lower incisors
What are examples of compromises in Class III DAC patients
Poorly defined labiomental sulcus
Prominent chin
Periodontal risks (lower incisors)
What are examples of compromises in patients after maxillary widening
Dehiscense/fenestration/gingival recession on surfaces of posterior teeth - Due to violation of transverse dimensions on dentoalveolar base
Decreased buccal corridors
What are examples of compromises in patients after incisor proclination
Fuller lips
Instability (risks relapse)
Fenestration, Dehiscence, Gingival recession
What are some Physiologic Limitations of orthodontics
- Systemic problems
- Medications
- Growth (growth modification, surgery)
Age-dependent
Genetically-programmed (diff pts respond differently)
Unpredictably/Latency (Esp class III)
What are systemic problems related to orthodontics
Diabetes: rapid progression of alveolar bone loss
Juvenile rheumatoid arthritis: progressive severe skeletal mandibular deficiency
Acromegaly (>GH): mandibular prognathism in adult life
What are medications related to orthodontics
Bisphosphonates (Osteoporosis): Inhibits osteoclast-mediated bone resorption –> teeth may not move as expected, wary of extraction as sockets may not be able to close
Prostaglandin inhibitors eg. corticosteroids, NSAIDs –> Beware of chronic use, high doses, potent members
Agents with agonistic or antagonistic effects on various prostaglandins
What are some therapeutic limitations of orthodontics
6+8
Anchorage
- Teeth vs Bone vs Soft tissue
- Periodontally compromised teeth
Type of appliance
- Removable vs fixed
- Partial vs full fixed appliances
Habits
- Digit sucking
- Forward tongue resting posture
Unrealistic expectations
Motivation/Compliance
Relapse
Smile Aesthetics
TMD
Impaction/Transposition (severity)
Ankylosis
Primary failure of eruption
What are some compliance limitations
- Multiple/Recurrent failed appointments
- Poor compliance with wear of removable appliances/elastics or retainers
- Repeated appliance breakage
- Diet
- Poor oral hygiene
What determines if there will be relapse
- Time needed for reorganization of periodontal and gingival tissues
- Initial tooth positive vs final unstable tooth position
- Continuation of growth pattern
- Habits
- Poor retention planning/compliance
- Specific surgical movements (overdone)
Other than orthodontics, what other components influences smile aesthetics? How can these be improved?
- Harmonious gingival margins
- intrude and restore
- gingivectomy and crown lengthening - Tooth proportions
- Reshaping (enameloplasty)
- Restorative options (veneers, CR) - Incisor and gingival display
- Reduces with age
Is malocclusion the cause of TMD
No, it is multifactorial
Does malocclusion affect TMD
High prevalence of malocclusion > prevalence of TMD by 10%
Does ortho cure TMD
NO
There may be a temporary cessation of parafunctional habits (eg. grinding) during ortho treatment due to soreness
What are some clinician factors that leads to failure in achieving treatment objectives?
- Errors in diagnosis
- Errors in treatment planning
- Errors in technique
What are some patient factors that leads to failure in achieving treatment objectives?
- Complexity of case (true therapeutic limitations)
- Anatomic or biologic factors
- Choice of treatment plan
- Unrealistic expectations
- Compliance-related factors
What are the risks in orthodontics
- Periodontal Issues
- Decalcification/Caries
- Devitalization
- Root resorption
- TMD
- Soft tissue inflammation
- Injury by orthodontic appliances
- Relapse
What are some periodontal issues that may arise due to ortho
- Gingivitis
- Periodontitis (at risk patients)
- Apical migration of periodontal attachment (Gingival recession)
What causes gingival recession in ortho
- Movement of teeth beyond alveolar process
- Thickness of soft tissue and alveolus
- Frenum position
- Periodontal disease
- Poor oral hygiene
- Trauma
How does the patient prevent gingival recession due to ortho
- Maintain good oral hygiene
- Regular recalls
- Have good oh prior to start of ortho
How does the clinician prevent gingival recession due to ortho
- Be mindful of anatomic limitations of tooth movement
- KIV pre-orthodontic soft tissue graft in patients at high risk of gingival recession
Is caries/decalcification risk very high in ortho
Wide range of prevalence
How to prevent Caries from ortho
- Good OH before and during orthodontic treatment
- Fluoride measures
- Dietary advice
- Terminate treatment if there is persistent poor OH
How can teeth be devitalised during ortho
- Over-enthusiastic apical movement
- History of trauma: increased susceptibility
- Deep caries
- Idiopathic
Management of devitalised teeth
- Counsel patient of risks prior to treatment
- Stabilize endo conditions of all teeth prior to ortho
Is root resorption always present in ortho
Yes it is inevitable but clinically insignificant (~1mm)
Do all patients have the same amount of root resorption from ortho and what type of pts are more susceptible
6+4
No
Some patients have increased susceptibility and severity of root resorption due to:
- genetics
- high forces of magnitude
- longer treatment duration
- total apical displacement
- type of tooth movement: intrusion
- Pre-existing RR
- Forced movement of roots against cortical plates
- Root morphology
- Dilacerations
- History of trauma
What tooth has a higher risk of root resorption
Maxillary incisors (3% vs <1%)
What to do if idiopathic root resorption has been observed
Pause the treatment for 3 months
Terminate treatment if it recurrs
What kind of soft tissue inflammation can arise due to rotho
Stomatitis
Traumatic ulceration
Allergies (Latex, Nickel)
