An anterior open bite can be described as the absence of vertical overlap between the upper and lower incisors when the
patient has their teeth in full occlusion. Anterior open bites can be asymmetrical or symmetrical. There is a greater incidence amongst patients of African origin (10 per cent) compared to Caucasians (one to two per cent). Adults or children might complain about the inability to use their incisors to bite into certain foods or ‘sewing thread’. Others might report speech defects, uncontrolled air and saliva escape or social embarrassment related to the tongue pushing through the front teeth.
A clinical examination might reveal a longer than average lower face, incompetent lips, or contact mainly limited to a few posterior teeth. These are classic signs associated with digitsucking or tongue thrusting. Careful orthodontic diagnosis should
lead to categorisation of most cases into two main groups; skeletal or dentoalveolar anterior open bites. The causes could be multi-factorial and may include genetic or hereditary influences, skeletal factors, soft tissue factors or iatrogenic causes.
Orthodontic management of anterior open bites can be challenging and generally involves devices designed to control or intrude posterior teeth whilst controlling or extruding teeth in the anterior segment. Some traditional open bite treatment devices or techniques can be perceived as ‘heavy duty’, obtrusive or not patient-friendly such as transpalatal bars with fixed appliances, high pull head gear, maxillary intrusion splints, extraction of terminal molars, intrusion of terminal molars using
Kim mechanics, fixed braces, bite blocks/magnets and in extreme cases orthognathic surgery.
Invisalign presents an acceptable method of tackling appropriately diagnosed anterior open bites of dento-alveolar origin. Using the clear aligner orthodontic system it is possible to manage many challenging cases including open bites.
The following case reports demonstrate the system’s capability to successfully treat moderate and severe anterior open bites without the assistance of elastic traction or fixed appliance auxiliaries.
Case 1
A 39 year old female patient presentedcomplaining of large gaps between her teeth and separation between her upper and lower teeth (figs 1–3). She had been treated 10 years previously with fixed braces and a maxillary frenectomy but the teeth had relapsed. Various comments had been made about her large tongue and she had been offered a partial glossectomy. She was unwilling to consider another course of fixed appliances.
Problems:
- 10mm anterior open bite
- Negative overjet [-3mm]
- Class III molars with bimaxillary incisal proclination
- Tongue thrusting habit
- Generalised spacing with 3.5mm maxillary midline diastema
- Upper centreline shift to the right
- Old discoloured crowns and gingival recession
- Uneven asymmetrical smile
Treatment plan:
- Patient was treated using the Invisalign full product to reduce the anterior open bite, close all the spaces, correct the centrelines and improve the occlusion
- Gingival re-contouring surgery to balance the smile and restore symmetry
- Replacement of crowns upper central incisors (UR1 and UL1)
- Veneers to elongate the upper lateral incisors (UR2 and UL2)
- The latter three components of the treatment plan were to be carried out by the patient’s general dental practitioner
Resolved by:
- Extrusion [relative] of the incisors
- Controlling the posterior segments – no deliberate intrusion
- Space closure
- Retroclination
Results achieved (figs 4–6):
- Reduction of the anterior open bite
- Correction of the class III malocclusion and overjet
- Correction of the centrelines
- Successful management of the case without worsening the gingival recession
Total treatment time:
- 24 months
Number of aligners:
- Maxillary: 28 + 18 = 46
- Mandibular: 28 + 18 = 46 The above illustrates 28 aligners in the original submission plus a further 18 aligners in the refinement
Comments:
- Multi-tooth extrusion attachments and optimised root control attachments were used
- One refinement was executed with new photos and new impressions
Retention:
- Maxillary: Permanent bonded retainer and Hawley retainer with acrylic fitted bow
- Mandibular: Permanent bonded retainer and Hawley retainer with acrylic fitted bow
Case 2
A 22 year old female patient presented complaining her teeth were moving in different directions, pointing directly to the two upper right incisors and unhappiness about the obvious gap in the front of her mouth (figs 7–8). She had gone through a course of upper fixed appliances when she was 12 years old. Although most of her concerns were cosmetic, she expressed a willingness to improve her bite.
Problems:
- 3mm anterior open bite
- Increased overjet [7mm]
- Class II division 1 malocclusion on a skeletal I base
- Crowding of the upper and lower arches
- Centrelines displaced to the right on the upper and lower arches
Treatment plan:
- Patient was treated using the Invisalign full product to close the anterior open bite, correct the overjet, centrelines and improve the occlusion
Resolved by:
- Extrusion [relative] of the incisors to produce 2-3mm complete overbite
- Controlling the posterior segments – no deliberate intrusion
- Interproximal reduction to resolve the crowding in both arches
Results achieved (fig 9–10):
- 1.5-2mm complete overbite
- Alignment of both arches
- Centreline improvement
Total treatment time:
- Maxillary: 18 months
- Mandibular: 10 months
Number of aligners:
- Maxillary: 21 + 17 = 38 (21 aligners in the original submission followed by 17 aligners in the refinement)
- Mandibular: 21 + 0 = 21 (21 aligners in total, no refinement aligners)
Comments:
- Multi-tooth extrusion attachments and optimized root control attachments were used
- One refinement was executed with new photos and new impressions
Retention:
- Maxillary: Permanent bonded retainer and Hawley retainer with acrylic fitted bow
- Mandibular: Permanent bonded retainer and Hawley retainer with acrylic fitted bow
Conclusion
Several treatment approaches with many useful techniques can be used to treat open bite cases. The two case studies above demonstrates how clear aligner treatment proved to be very effective in treating complex open bite cases.
References available on request.