🦷💭 “Open Bite Correction Always Relapses… Right?”
Think again.
For decades, orthodontists have feared the words “open bite relapse.”
We’ve all seen those post-surgical cases where the overbite slowly flattens out again, leaving both the clinician and the patient frustrated.
But recent evidence tells a more optimistic story.
We looked at three landmark studies that prove surgical open bite correction can, in fact, stay stable long-term — if planned and executed correctly.
Let’s break it down 👇
🧠 Why Does Open Bite Relapse Happen?
Open bites often involve vertical skeletal discrepancies, soft-tissue imbalances, and habit-related influences (like tongue thrust or mouth breathing).
Even after successful closure, relapse can creep in because of:
- Posterior mandibular rotation post-surgery
- Muscle and condylar adaptation
- Incomplete control of incisor inclination
- Prolonged vertical elastics or residual tongue posture
Understanding these helps us choose treatment options that offer the best long-term stability.
🔍 What Does the Evidence Show?
🔹 1. Bimaxillary Surgery: Fischer et al., 2000 (EJO)
This study followed 58 patients who underwent Le Fort I osteotomy + Bilateral Sagittal Split Osteotomy (BSSO) to correct open bite and mandibular retrognathism.
🩺 Findings after 2 years:
- The maxilla stayed stable.
- The mandible rotated back by only 1.4°, showing mild skeletal relapse.
- 17 patients developed a small open bite again, mostly due to incisor proclination, not jaw rotation.
- The most stable results occurred in patients who had no post-op MMF (maxillomandibular fixation) — early mobilization helped muscles adapt better.
💡 Take-home:
Rigid fixation + early mobilization = better stability.
🔹 2. Mandibular-Only Surgery: Fontes et al., 2012 (AJODO)
This study challenged the belief that we must operate on the maxilla for every open bite case.
It followed 31 patients treated with BSSO and closing mandibular rotation only (no maxillary impaction).
📊 Results after 4.5 years:
- Initial open bite: –2.6 mm
- Surgical correction: +3.7° closing rotation of mandible
- Long-term: 90% maintained positive overlap!
- Even though about 60% of the rotation was lost, only 3 patients relapsed to zero overbite.
💡 Take-home:
For mild-to-moderate skeletal open bites, mandibular-only surgery can be predictably stable and avoids unwanted soft-tissue changes (like widened nasal base or flattened upper lip).
3️⃣ Surgical vs. Nonsurgical Approaches – What’s More Stable?
Greenlee et al., 2011 — The Meta-Analysis That Ties It Together
This systematic review pooled data from 21 studies on open bite correction — both surgical and nonsurgical.
📈 The big picture:
- Surgical treatments: ~82% stability (positive overbite ≥ 1 year post-op)
- Nonsurgical treatments: ~75% stability
- Average relapse in overbite: < 0.5 mm over 3–4 years
💡 Take-home:
Both surgical and orthodontic approaches can be stable when case selection, fixation, and retention are well managed.
⚙️ Clinical Insights for Students
| Focus Area | Key Point for Practice |
|---|---|
| Case selection | Choose surgical correction for true skeletal AOB with steep mandibular plane angles. |
| Fixation method | Rigid internal fixation (plates/screws) > wire fixation. |
| Incisor control | Avoid proclination of upper/lower incisors post-surgery. |
| MMF duration | Short or no MMF enhances functional recovery and stability. |
| Post-op care | Encourage physiotherapy and early functional movement. |
| Retention | Prolonged retention and habit control are essential to prevent vertical relapse. |
| Parameter | Pretreatment | Post-Surgery | Long-term Follow-up | Change/Relapse |
|---|---|---|---|---|
| Mean open bite (BSSO) | –2.6 mm | +1.4 mm | +1.0 mm | 0.4 mm relapse |
| Mandibular rotation | +3.7° closing | –2.2° reopening (4.5 yrs) | 60% rotation loss | Clinically stable outcome |
| Bimaxillary (Fischer et al.) | –0.9 mm | +2.2 mm | +0.8 mm | ~1.4° mandibular reopening |
| Pooled (Meta-analysis) | –2.8 mm | +11.6 mm | +10.3 mm | 82% maintained positive OB |
References:
- Fischer K, von Konow L, Brattström V. Eur J Orthod. 2000;22:711–718.
- Fontes AM, et al. Am J Orthod Dentofacial Orthop. 2012;142:792–800.
- Greenlee GM, et al. Am J Orthod Dentofacial Orthop. 2011;139:154–169.
🦷 Clinical-Oriented MCQs: Anterior Open Bite Stability After Surgery
1.
A 25-year-old female underwent bimaxillary surgery (Le Fort I impaction and BSSO) for anterior open bite. Two years later, her cephalometric evaluation shows a 1.4° posterior rotation of the mandible.
What is the most likely reason for this relapse?
A. Condylar sag during fixation
B. Maxillary relapse
C. Incisor proclination and dentoalveolar compensation
D. Nasal soft-tissue tension
✅ Answer: C. Incisor proclination and dentoalveolar compensation
🩺 Explanation: Fischer et al. (2000) reported that the mild relapse seen in 17/58 patients was primarily due to dental changes (incisor proclination), not skeletal instability.
2.
Which fixation method is most strongly associated with long-term stability in open bite surgery?
A. Wire osteosynthesis
B. Rigid internal fixation using plates and monocortical screws
C. Intermaxillary fixation for 8 weeks
D. External pin fixation
✅ Answer: B. Rigid internal fixation using plates and monocortical screws
🩺 Explanation: Rigid fixation provides superior skeletal stability and minimizes posterior mandibular rotation. (Fischer et al., 2000; Fontes et al., 2012)
3.
In Fontes et al. (2012), which surgical technique was assessed for its long-term stability in anterior open bite correction?
A. Le Fort I impaction of the maxilla
B. Bimaxillary osteotomy
C. Bilateral sagittal split osteotomy (BSSO) with closing rotation of the mandible
D. Segmental maxillary osteotomy
✅ Answer: C. Bilateral sagittal split osteotomy with closing rotation of the mandible
🩺 Explanation: The study specifically evaluated BSSO with rigid internal fixation and found 90% of patients maintained a positive overbite 4.5 years post-treatment.
4.
What was the long-term success rate (positive overbite ≥1 year post-op) for surgical open bite treatment according to Greenlee et al. (2011)?
A. 60%
B. 70%
C. 82%
D. 90%
✅ Answer: C. 82%
🩺 Explanation: The meta-analysis reported an 82% success rate for surgical interventions and 75% for nonsurgical treatment in maintaining positive overbite.
5.
During open bite correction, which factor most increases the risk of relapse due to soft tissue and muscular tension?
A. Steep mandibular plane angle
B. Reduced condylar height
C. Excessive mandibular closing rotation (>4°)
D. Small gonial angle
✅ Answer: C. Excessive mandibular closing rotation (>4°)
🩺 Explanation: Over-rotation increases muscular stretch and pterygoid tension, contributing to relapse (Fontes et al., 2012).
6.
Which postoperative protocol demonstrated the most favorable stability outcomes in bimaxillary surgery cases?
A. 8-week maxillomandibular fixation
B. 1–3 weeks of MMF
C. No MMF with early mobilization
D. Rigid fixation followed by elastic traction
✅ Answer: C. No MMF with early mobilization
🩺 Explanation: Fischer et al. (2000) found the most stable overbite in patients without MMF, suggesting early mobilization promotes muscle adaptation and healing.
7.
In mandibular-only surgery for open bite, approximately what percentage of surgical closing rotation is typically lost long-term?
A. 10%
B. 30%
C. 60%
D. 80%
✅ Answer: C. 60%
🩺 Explanation: Fontes et al. (2012) reported that about 60% of the mandibular closing rotation achieved at surgery was lost, yet functional overlap was maintained.
8.
Which cephalometric parameter was significantly correlated with open bite relapse post-surgery?
A. ANB angle
B. SN–ML angle (mandibular plane angle)
C. U1–L1 interincisal angle
D. SNA angle
✅ Answer: B. SN–ML angle
🩺 Explanation: Increased mandibular plane angles are associated with vertical skeletal patterns that predispose to relapse (Fischer et al., 2000).
9.
Why might mandibular-only BSSO be preferred over maxillary impaction surgery in some open bite cases?
A. It allows greater anterior movement of the maxilla
B. It produces fewer unfavorable nasal and upper lip changes
C. It reduces operation time by half
D. It eliminates the need for orthodontic finishing
✅ Answer: B. It produces fewer unfavorable nasal and upper lip changes
🩺 Explanation: Fontes et al. (2012) noted mandibular-only correction avoids side effects like nasal widening, upper lip thinning, and excessive gingival display.
10.
Which of the following best summarizes the long-term evidence on open bite surgical stability?
A. Relapse is inevitable due to vertical muscle pull.
B. Only bimaxillary surgery yields stable results.
C. Both surgical and nonsurgical approaches show >75% long-term stability.
D. Stability depends only on orthodontic retention.
✅ Answer: C. Both surgical and nonsurgical approaches show >75% long-term stability.
🩺 Explanation: Greenlee et al. (2011) meta-analysis found 82% stability for surgical and 75% for nonsurgical corrections at ≥1-year follow-up.
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