Overview: This guide helps dental practices identify profitable and predictable clear aligner cases while estimating treatment length using the "Rule of 3" framework.
Evaluate Case Predictability with the Rule of 3
The "Rule of 3" is a framework used to identify case predictability based on specific treatment goals. To use this guide, track how many of the following goals apply to a potential clear aligner case:
Predictable Treatment Goals
Midline Discrepancy: Maximum of 1.5 mm of shift per arch; requires Interproximal Reduction (IPR) and sufficient overjet.
Overjet Reduction: Requires IPR on the maxillary (upper) arch.
Open Bite Reduction: Anterior open bites are highly predictable for only 1–2 mm of closure.
Other Goals: Includes overbite correction, anterior spacing per arch, anterior crowding per arch, and crossbite per teeth.
Estimate Clear Aligner Treatment Duration
Clinicians should use the following thresholds to provide patients with a treatment time range:
Short Duration (6–8 Months): Cases presenting three or fewer treatment goals.
Moderate Duration (12–14 Months): Cases presenting four or more treatment goals OR moderate anterior spacing/crowding up to 6 mm.
Review Clear Aligner Contraindications
Certain dental conditions significantly reduce the predictability of clear aligner outcomes and may require alternative treatments.
Class III Cases: Clear Aligners Powered by Dandy are not indicated for Class III malocclusions.
Mutilated Dentition: Lack of posterior support, loss of vertical dimension, or compromised periodontal conditions reduce anchorage and predictability.
Impacted Teeth: These can cause root resorption or require surgical intervention.
Transitional Dentition: Children and adolescents require special consideration for facial growth and eruption timing.
Ectopic Teeth: These teeth require specialized management and auxiliaries.
Identify Common Malocclusion Types
Recognizing specific dental misalignments is essential for determining if a patient is a suitable candidate for clear aligner treatment.
Malocclusion Descriptions
Overbite: The upper front teeth significantly overlap the lower front teeth vertically.
Underbite: The lower front teeth extend past the upper front teeth when the jaw is closed.
Crossbite: Upper teeth sit inside the lower teeth rather than outside when biting down.
Crowding: Insufficient jaw space causes teeth to overlap or twist.
Spacing: Noticeable gaps or "diastemas" exist between two or more teeth.