Advisor(s)

Chung Kau

Committee Member(s)

Amjad Javed
Don Spillers
Elvis Lamani

Document Type

Thesis

Date of Award

7-16-2026

Degree Name

Master of Science (MS)

School

School of Dentistry

Department

Dentistry

Abstract

Palatal expansion has been used in orthodontics to treat a narrow maxilla and to primarily correct posterior dental crossbites. In younger patients, palatal expansion can readily be achieved through opening of the mid-palatal suture, as it is not fused at that age. As the mid-palatal suture matures, expansion will gradually be difficult to achieve, and more dental expansion is obtained rather than skeletal. In addition, there is a tendency to get more dental tipping. Palatal expansion has been recommended not only to correct crossbites but also to improve breathing in patients with sleep disorders such as obstructive sleep apnea (OSA). The ratio skeletal/dental expansion decreases as the patient grows older and the mid-palatal suture fuses. Mini-implant supported RPE (Marpe) or Surgically assisted RPE (Sarpe) are considered when palatal expansion is needed for patients with fused mid-palatal suture. Recently ALIGN technologies introduced the Invisalign Palatal Expander (IPE)1 which consist of a series of removable palatal expansion. This study aimed at evaluating palatal expansion using the Invisalign palatal expander “IPE”. Intraoral scans with Itero scanners from a total of 41 patients were used and evaluated for expansion. The inclusion criteria for the study were patients primarily age between 9 and 10, with the presence of maxillary first permanent molar. These patients were sub-divided into 2 groups; Group 1 included 41 patients with pre and post expansion intra-oral scans. Intermolar width before and after expansion with the IPE was measured on the scans from palatal cusp tip, mesial-palatal cusp at CEJ, Buccal cusp at CEJ, and from central fossa. Group 2 included 14 patients who had both pre and post expansion CBCTs, in addition to pre and post expansion intra oral scans. The exact same measurements were carried out on scans in both groups to evaluate the intermolar width at different levels. To quantify the effect of the palatal expansion in group 2, intermolar width measurements were also taken on the CBCTs (molar palatal cusp tip to cusp tip and central fossa to central fossa). Additional skeletal measurements included: nasal floor width at the 6 level, nasal width, hard palate width, palatal alveolar molar width, buccal alveolar molar width. The angle formed by the two lines passing through the palatal roots of the 1st molars was measured in an attempt to evaluate amount of tipping of the molars. The results showed a total expansion between 4.5 mm and 8.1mm. Increases in dental measurements on the intra-oral scans measured between 2.7mm to 9.8mm from fossa to fossa and 2.8mm to 11.3mm from palatal cusp tip to palatal cusp tip. Skeletal expansion as depicted by the mid-palatal suture expansion was under 3 mm both in the molar and the premolar region. The average mid-palatal opening occurred at 1.49 mm and 1.5 mm at the molar level and the premolar level respectively. Conclusions: IPE resulted in both dental and skeletal expansion as seen on intra-oral scans and verified on patients CBCTs.

Keywords

dental palatal expansion;invisalign;Invisalign Palatal Expander;IPE;palatal expansion;skeletal palatal expansion

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