CLINICAL GUIDE

Case Selection and Movement Protocols

How to select the right cases for Active Aligners, indications, candidacy, and the movement philosophy and clinical limits behind predictable outcomes.

Download the full guide (PDF)
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Indications for Active Aligners treatment

Active Aligners is indicated for the following presentations.

Mis-alignment

Mis-alignment of teeth from first pre-molar to first pre-molar.

Crowding

Crowding of teeth.

Spacing

Spacing of teeth.

Pre-restorative alignment

Pre-restorative anterior alignments (pre-planning for veneers, etc.).

Anterior aesthetics

Beneficial anterior aesthetic treatments.

Mild posterior

Mild posterior alignments.

Anterior case selection

Treatable

  • Mild spacing
  • Mild crowding
  • Midline discrepancy <2mm (with IPR)
  • Deep bite (<2mm of anterior intrusion)
  • Basic alignment prior to restorative work
  • Mild anterior open bite correction (<2mm)
  • Lower incisor extraction (space closure <2mm)
  • Bicuspid extraction (space closure <2mm)
  • Mild anterior cross bite

Not treatable

  • Midline discrepancy >2mm
  • Severe deep bite
  • Severe skeletal open bite
  • Severe crowding
  • Class III bite / underbite
  • Full posterior crossbite correction

Posterior case selection

Treatable

  • Mild/moderate spacing
  • Mild/moderate crowding
  • Improving cusp/fossae relationship
  • Class I correction
  • Mild Class II correction
  • Molar uprighting

Not treatable

  • Extraction cases
  • Open bites / deep bites
  • Full posterior crossbite correction
  • Edge-to-edge bite
  • Class III bite / bite change
  • Severe skeletal open bite
  • Midline discrepancy >2mm

Candidacy (case selection, incl. teens)

Active Aligners handles a wide range of cases, from simple alignment to genuinely complex movements, always dentist led. Complexity is not a barrier, our planners build for it. A more complex case does bring a higher chance of a refinement, though many complex cases still finish first time. Only rare exceptions are better referred to a specialist, such as a deeply palatally impacted tooth or a high eye tooth, positions where an aligner cannot wrap around the tooth well enough to grip and move it. The clinical criteria below describe those physical limits and the movement protocols behind predictable outcomes, they are not a cap on how difficult a case can be.

Requirements

  • Only fully erupted permanent dentition (no primary or erupting teeth)
  • Ensure enough clinical crown is available to support the aligner and facilitate movement
  • X-rays (Ceph or Pan) are critical to rule out impacted, non-erupted, missing or ankylosed teeth and to assist diagnosis
  • Patient must be committed, motivated and responsible, compliance is key
  • Ideal cases create space through expansion and proclination with limited IPR; crowding is well within scope and our planners build for more complex movements too, the clinical limits below are about what an aligner can physically grip and move, not a ceiling on case difficulty

Avoid

  • Avoid deep curves of Spee in the lower arch (lower incisors over-erupted)
  • Avoid over-advancement of the lower incisors
  • Avoid iatrogenic gingival recession, especially in the lower anterior region
  • Avoid larger open bites extending beyond the anterior segments

Case selection tips

Good cases to begin with

Minor anterior spaces or crowding; ortho relapses; single-arch treatment (minor changes for the desired outcome).

Progress to

Moderate anterior spaces or crowding; minor-to-moderate overjet and overbite correction; Class II and Class III cases.

The only way to be sure a patient is a candidate is to submit the case for treatment planning. This carries a treatment-plan fee, which is refunded if the case is rejected for Active Aligner treatment by the planners.

Movement philosophy and clinical criteria

Our aligner and movement philosophy is based on being the least invasive, using maximum arch expansion, allowing minimal IPR (interproximal reduction), and using attachments where necessary to ensure predictable movement and outcomes.

Movement limits

  • 4 to 6mm of crowding or spacing, with a maximum of 2 to 3mm overlap
  • Up to 40° of rotation
  • 1.5mm of expansion per side
  • 1.5mm of overbite correction per arch for intrusion or extrusion (with attachments)
  • 14° tooth inclination
  • 4mm per-arch IPR limitation

Rotation protocols

  • Protocol 1, 28° anterior (5° posterior teeth, without attachment)
  • Protocol 2, 32° anterior with attachment (premolar movements allowed)
  • Protocol 3, 40° anterior with attachment (molar movements allowed)

Detailed per-protocol, per-tray movement tables (anterior and full-arch maxima for rotation, inclination, angulation, extrusion/intrusion and translation) are in the downloadable guide above.