The ortho expert – Invisalign case study part three: periodontal drifting and a class III malocclusion

The Ortho ExpertNeil Patel continues his Invisalign case study treating periodontal drifting and a class III malocclusion.

This patient was concerned about ‘spacing between the front teeth, crowding and a horrible smile’. He presented with a class III incisor relationship on a class I skeletal base, increased vertical facial heights and no significant transverse discrepancy.

The main features of his malocclusion included:

  • Periodontal disease BPE 232/233
  • Moderate crowding in the upper arch
  • Buccal crossbite tendencies
  • Proclined and spaced lower arch
  • Ill fitting lower bonded retainer
  • Asymmetric smile curve.

Medical history


Social history

Smokes five times a day.

Dental history

Regular attendee, electric toothbrush once daily and the occasional use of interdental brushes.

Previous lower orthodontic treatment retained with a fixed bonded retainer, no removable retainer was provided.

Case based discussion

The patient noticed his lower teeth protruding forward relative to his upper teeth over the last five years. On examination he presented with a traumatic bite associated to the lower central incisors, mild recession and grade one mobility of these teeth.

It was paramount before any orthodontic treatment we address the patient’s smoking and periodontal status. This is to ensure the periodontium is stable and healthy prior to orthodontic tooth movement. We referred the patient to a specialist periodontist prior to starting treatment.

Six months later the patient returned. During the review appointment we noted the following key points:

  1. The patient stopped smoking
  2. BPE: 101/100
  3. The patient was now brushing twice a day.

A joint discussion with the patient, periodontist and also the orthodontic team led to the decision that the patient was now dentally fit for orthodontic treatment.

Orthodontic planning involved a full set of patient records and removing the ill-fitting bonded retainer. A 3D intraoral scan was therefore taken, extra-oral, intraoral photos and a DPT to assess bone levels, crown/root health and to ensure no other pathology was noted.

Treatment objectives

  1. Align and level upper and lower arches
  2. Expand the upper arch to eliminate crossbite tendencies in the buccal segments
  3. Extrude the buccal segments to improve occlusal contacts and interdigitation
  4. Improve inclination of the lower teeth by retroclining them into a class I occlusion. This in turn would then eliminate the anterior crossbite, traumatic bite and reduce the risk of damage to the periodontium of the lower incisors
  5. Smooth the upper and lower incisors to enhance and improve smile symmetry.

Case comments

This is a case where orthodontics was not a priority until we addressed the patient’s smoking and periodontal status.

We set up the Clincheck with minimal inter-proximal reduction (IPR) in the upper arch. And also planned mild expansion to aid buccal crossbite tendency correction.

To minimise any retroclination of the upper labial segment, we set up the Clincheck to procline the upper incisors with additional buccal crown torque.

We prescribed IPR in the buccal segments of the lower arch to constrict arch width and aid arch coordination.

Premolar and molar attachments were also placed to extrude the buccal segments and obtain greater occlusal contacts.

As the patient’s oral hygiene was meticulous throughout treatment, upper and lower permanent bonded retainers were then placed along with clear thermoplastic retainers at nights.


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