Bella Smile ↗Case report · Early / interceptive
Thumb Sucking Open Bite & Narrow Palate Correction with a Palatal Expander and Braces
This 7-year-old patient presented with a severe 6 mm anterior open bite, a persistent left thumb-sucking habit, and a narrow, constricted palate. Additional findings included a tongue-thrust swallowing pattern, abnormal anterior tongue posture, and a missing lower incisor. The combination of the thumb-sucking habit, tongue thrust, and transverse maxillary constriction was contributing to the developing open bite and abnormal eruption pattern.
- Patient
- Child (under 12), female
- Classification
- Class I
- Active treatment
- 12 months
- Published
- September 8, 2026
Presentation
Chief complaint. " I want to fix the hole when I smile and the uneven gums."
Diagnosis. The patient presents with a Class I dental relationship and a severe 7 mm anterior open bite with 5 mm of overjet. The open bite is more pronounced on the left side, consistent with her persistent left thumb-sucking habit, which occurs during both the day and night. Additional findings include: Constricted maxillary arch Moderate upper arch crowding Adequate space in the lower arch Lips together at rest No reported TMJ pain or symptoms Persistent daytime and nighttime thumb-sucking habit The patient is motivated to discontinue the thumb-sucking habit. The asymmetric anterior open bite and constricted upper arch are consistent with the dental changes commonly associated with a persistent digit-sucking habit.
Records
Before — Intraoral Photos
After — Intraoral Photos
Before — Lateral Ceph Radiograph
After — Lateral Ceph Radiograph
Before — Panoramic Radiograph
After — Panoramic RadiographMeasurements
| Measure | Norm | Pre | Post |
|---|---|---|---|
| SNA | 82 | 79 | 79 |
| SNB | 80 | 78 | 77 |
| ANB | 2 | 1 | 2 |
| Wits | 0 | 0 | 1 |
| SN-MP | 32 | 24 | 24 |
| U1-SN | 102 | 126 | 115 |
| L1-MP | 90 | 111 | 107 |
| Overjet (mm) | 2–3 | 5 | 4 |
| Overbite (mm) | 2–3 | -7 | 1 |
Treatment
Objectives. Eliminate the thumb-sucking habit Expand and develop the upper arch Close the anterior open bite Reduce the excessive overjet Improve anterior tooth alignment and create more even gingival margins Establish a more balanced and functional anterior bite
Plan. Place a Rapid Palatal Expander (RPE) with a built-in vertical thumb crib to expand the constricted maxillary arch while helping eliminate the thumb-sucking habit. Once the thumb-sucking habit has been successfully discontinued, remove the thumb-crib component while maintaining the expansion. Band the first permanent molars (6s) and bond canine-to-canine (C–C). Level and align the anterior teeth with Phase I braces. Monitor improvement of the anterior open bite, overjet, arch form, and eruption of the developing permanent teeth throughout treatment.
Appliances and materials
- Rapid Palatal Expander — with vertical thumb crib built in
Progress records
Outcome
The patient successfully stopped her thumb-sucking habit, an important goal of Phase I treatment. The anterior open bite was successfully closed, and the gingival margins became more level. Oral hygiene was poor during braces treatment, and gingival inflammation was present at the time of debonding. The final overjet remained slightly increased, in part due to the missing lower incisor, which limited the ideal anterior tooth relationship.
Retention
- Upper and lower Hawley retainers to be worn full time for 6 months and then nighttime only
Case reports are shared with patient authorisation. Individual results vary.