Limitations and Risks in Orthodontics Flashcards by Nicole Chng

What are the limitations in Orthodontics

Anatomic
Physiologic
Therapeutic

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What are some anatomic limitations of orthodontics

Skeletal discrepancies - AP, Transverse, Vertical (size)
Alveolar ridge
Space
Soft tissue

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What are the treatment options for skeletal discrepancies

Growth modifications (growing patients)
Orthognathic surgery (adults)

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What is the advantages of miniscrews

It broadens the maximum envelope of tooth movement

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Which can be expanded transversely more? Lower or upper jaw

Upper (mid-palatal suture)

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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

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How is alveolar ridge an anatomical limitation?

Early extraction creates an alveolar bone defect which causes risk of fenestration/dehiscence/gingival recession

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How much can you procline incisors and what happens if you exceed this limit?

2mm
>2mm causes instability

But also dependent on initial position

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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

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What are some compromises due to anatomical limitations in orthodontics

Health
Aesthetics
Function
Stability

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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

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What are examples of compromises in Class III DAC patients

Poorly defined labiomental sulcus
Prominent chin
Periodontal risks (lower incisors)

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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

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What are examples of compromises in patients after incisor proclination

Fuller lips
Instability (risks relapse)
Fenestration, Dehiscence, Gingival recession

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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)

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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

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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

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

1. Periodontal Issues 2. Decalcification/Caries 3. Devitalization 4. Root resorption 5. TMD 6. Soft tissue inflammation 7. Injury by orthodontic appliances 8. Relapse

What are some periodontal issues that may arise due to ortho

1. Gingivitis 2. Periodontitis (at risk patients) 3. 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)