What are the considerations and treatment outcomes for a patient with mild to moderate malocclusion and good oral hygiene who is considering Invisalign (clear aligners)?

Invisalign for Mild to Moderate Malocclusion

For patients with mild to moderate malocclusion and good oral hygiene, Invisalign (clear aligners) is an effective treatment option that achieves comparable outcomes to conventional fixed appliances, with faster treatment times and superior patient comfort, though it may be less effective for achieving "great improvement" in more complex cases. 1

Treatment Effectiveness

Clear aligners effectively improve mild to moderate malocclusion, with all treated patients achieving more than 30% reduction in PAR (Peer Assessment Rating) scores. 1 The posttreatment outcomes between Invisalign and fixed appliances show no statistically significant difference in final PAR scores. 1

Specific Movement Predictability

• Buccolingual tipping is the most predictable movement with clear aligners. 2
• Rotation, intrusion, and extrusion are the least predictable movements, often requiring refinement or additional aligners. 2, 3
• Mild to moderate crowding resolution is highly effective with aligner treatment. 2
• Overbite correction success remains limited, particularly for deep bites exceeding 7mm, though case reports demonstrate feasibility with proper auxiliaries and attachments. 2, 4

Treatment Efficiency

Invisalign patients complete treatment an average of 5.7 months faster than those with conventional fixed appliances (P = 0.0040). 1 However, treatment duration depends on orthodontist experience, case complexity, and patient compliance. 3

Refinement Requirements

• 69% of interceptive cases are resolved with the first set of aligners, with the remaining 31% requiring additional aligners. 5
• Refinement (additional intervention during treatment) is frequently necessary to achieve optimal end results, particularly for difficult movements like extrusion, rotation, or overjet correction. 3

Patient-Centered Outcomes

Patients experience minimal limitations in daily activities and significantly less pain compared to fixed appliances. 3 Clear aligners provide superior aesthetics and better oral hygiene maintenance compared to conventional brackets. 4

Critical Limitation

The odds of achieving "great improvement" with Invisalign are 0.329 times the odds with fixed appliances (P = 0.0150), after controlling for age. 1 This means patients with fixed appliances are approximately 3 times more likely to achieve "great improvement" in their malocclusion compared to Invisalign patients.

Treatment Selection Algorithm

Ideal Candidates for Invisalign:

• Mild to moderate malocclusion severity (PAR scores 20-23) 1
• Primary concern is buccolingual tipping or mild crowding 2
• Patient prioritizes aesthetics and comfort over maximal correction 4, 3
• Good oral hygiene already established 1
• High patient compliance expected 3

Consider Fixed Appliances Instead:

• Complex rotations requiring correction 2, 3
• Significant extrusion or intrusion needed 2, 3
• Large overjet corrections required 3
• Patient seeks "great improvement" rather than "improvement" 1
• Severe malocclusion (not addressed in mild-moderate cases) 1

Cost Considerations

Treatment costs for Invisalign are higher than conventional fixed appliances, and treatment planning typically requires more orthodontist time than fixed-appliance therapy. 3

Common Pitfalls to Avoid

• Do not assume predictability matches the digital ClinCheck® prediction—the degree of predictability is overestimated and does not accurately reflect the occlusion immediately at treatment end. 2
• Do not select Invisalign for cases requiring significant rotation, extrusion, or intrusion without counseling patients about likely need for refinement. 2, 3
• Do not overlook the need for proper auxiliaries and attachments when treating more complex cases like Class II with deep bite. 4