Treatment of transverse alveolar and basal anomalies
1.Introduction
Maxillomandibular anomalies of the transverse direction are a major component of many malocclusions. They require early management . The etiologies range from para- or dysfunctional to kinetic origins.
Transverse treatment is a priority in orthodontics . In children, a preventive or even interceptive therapeutic phase allows a balanced occlusion to be quickly restored and thus guarantees harmonious transverse growth.
On the other hand, in adults, transverse dysmorphias are treated by a combination of orthodontic, orthopedic and even surgical techniques.
Treated early or late, long-term stabilization is necessary in order to limit transverse recurrence.
2. Reminder of the different clinical forms of transverse dysmorphia
These transverse pathologies may be located in the maxilla, due to alveolar or basal deficiency or excess, and/or in the mandible, associated or not with a functional laterodeviation.
These dysmorphias can be alveolar, kinetic or basal.
- Alveolar anomalies of the transverse direction
In the maxilla:
Symmetrical maxillary endoalveolus without mandibular laterodeviation;
Symmetrical maxillary endoalveolism with mandibular laterodeviation;
Bi-endoalveolism;
Unilateral maxillary endoalveolism;
Maxillary exoalveolism.
In the mandible:
Mandibular endoalveolitis;
Mandibular exoalveolism.
- The kinetic anomaly of the transverse direction
It is represented by the mandibular laterodeviation of functional origin (a prematurity on the path of physiological closure). Generally these prematurities are located, in the milk teeth, at the level of the milk canines.
- Basal anomalies of the transverse sense:
Symmetrical maxillary endognathism with bilateral crossbite;
Symmetrical maxillary endognathism without crossbite due to alveolar or basal mandibular compensation;
Mandibular laterognathia: Structural laterognathia can have a functional origin (development of a laterodeviation), genetic (hypercondylia, hypocondylia) or acquired (ankylosis, autoimmune diseases, example: rheumatoid arthritis).
3. Etiological treatment of transverse sense anomalies
Intercepting these anomalies means acting early to prevent the malocclusion from worsening and avoiding the onset of dysmorphia which will become more complicated with age.
3.1. Ventilation rehabilitation:
“Oral ventilation and lingual and jugal dysfunction significantly degrade the harmony of maxillary growth and their rehabilitation is one of the first steps to be taken to restore its transverse dimension.”
If mouth breathing is diagnosed, other causes associated with the dental problem must be sought: deviated septum, hypertrophy of the turbinates, allergic rhinitis, polyps, etc. The advice of the pediatrician is then essential.
Limme believes that the therapeutic approach to mouth breathers requires the intervention of three disciplines: orthodontics, speech therapy and otolaryngology.
The functional objectives of this type of treatment:
– resumption of the nostril reflex,
– learning diaphragmatic breathing,
– the disappearance of inflammatory phenomena of the pharyngeal mucous membranes,
– the loosening of the veil,
– recovery of relaxed lip contact.
3.2. Re-education of lingual posture :
Boileau and Duchateau point out that a low lingual position has often been associated with transverse dysmorphia due to deficit.
This is how the lingual posture must be re-educated both at rest and in function.
In some cases where the tongue is held by a hypertrophic or short frenulum we observe a mirror maxillary endognathia. It is therefore essential to free the movement of the tongue by a lingual frenulumectomy.
Treatment of transverse alveolar and basal anomalies
3.3. Rehabilitation of mastication using the Planas method:
Planas, for whom the influence of functions on growth is primordial in relation to hereditary potential, advocates the re-education of mastication.
The objectives of this rehabilitation:
Muscular symmetrization of masticators
Alternate bilateral chewing
The re-centering of the condyles in their glenoid cavity, hence the straightening of the occlusal plane.
To achieve this refocusing, Planas recommends selective grinding of the temporary teeth responsible for occlusal disturbances. This therapy is always implemented in temporary dentition.
3.4. Elimination of excessive judicial pressure:
In case of jugal hypertonicity, a Fränkel function regulator is used.
Thanks to its cheek screens, the Fränkel function regulator allows the neutralization of cheek pressure, which leads to a passive transverse expansion of the dental arch.
4. Active treatment of transverse alveolar anomalies
4.1. Treatment of maxillary endoalveolism:
- In temporary dentition:
The inward tilt of the alveolar processes requires lateral expansion of the arches with simple means.
Sometimes, all it takes is therapy to resolve the problem.
In other cases, devices are required to correct a unilateral or bilateral crossbite.
The devices used are:
- Removable plate with central jack , This is the most commonly used device. It allows the occlusion to be corrected progressively by the action of a central or asymmetrical jack activated regularly by the parents.
The lifting of the reverse articulation by expansion is aided by a molar over-occlusion plane or by the placement of posterior shims. These glass ionomer shims on the molars are gradually eliminated as the correction progresses.
- A quad helix on a splint , very well tolerated by children. This device does not require any manipulation on the part of the parents, unlike removable devices. The splints serve as a molar elevation plane ensuring easier correction. They must be thick enough to ensure chewing without breakage.
- In mixed dentition:
We can use:
- Removable expansion plates with cylinder . These will be little used, because of the poor control of molar rotation.
- A quad helix on bands sealed on the first maxillary molars allows for correction of the transverse direction in a maximum of six months. It can be fitted with welded auxiliaries, such as an anti-tongue grid or an anti-thumb device.
- In adult teeth:
At this stage, the alveolar expansion of the maxilla involves a quadhelix .
The Quad Helix: This is a palatal arch designed by Ricketts, reproducing the shape of the letter W and with the addition of four internal loops providing the necessary flexibility of action.
Activation of the quadhelix can be done in two ways, using the three-nose pliers:
– Intraoral activation;
– Extraoral activation.
- Arndt developed an expansion device, the “expander”, made of nickel-titanium, derived from the quadhelix, and whose effects are comparable to those obtained by the quadhelix without the need for activation.
The Niti expander: also called the Nitanium Molar Rotator (NMR), this device has the following advantages:
- Ease of installation;
- Accuracy in the degree of activation depending on the chosen NMR dimension;
- Multiple unnecessary reactivations;
- Effective molar expansion, achieved between three and five months;
- Rapid molar derotation;
- Combined with a superplastic arch with shape memory, it increases maxillary expansion;
- Has several variations.
Treatment of transverse alveolar and basal anomalies
4.2. Treatment of mandibular endoalveolitis:
The means of expansion of the mandibular arch are:
- Lower plate with transverse expansion cylinder;
- The Bi helix;
- The bi helix-Crozat which differs from the bihelix by its anterior springs welded on the lateral arms and which serve to vestibulate the lower incisors.
4.3. Treatment of maxillary exoalveolism:
- Palatal plate with open cylinder
- Quad helix or a contraction Niti expander.
5. Active treatment of basal anomalies of the transverse sense
5.1. Treatment of maxillary endognathism:
Before starting the different therapies envisaged in the face of maxillary endognathism, it is necessary to recall Melsen ‘s work on the midpalatal suture:
- Infantile stage: from birth – 10 years, “Y” shaped suture, wide and straight;
- Juvenile stage: 10 to 13 years, the suture is sinuous, sections invaginate on either side;
- During adolescence, around 13-14 years of age, the palatine suture becomes even more sinuous and presents more large-amplitude interdigitations;
- Adult stage The palatine suture is synostotic and presents more pronounced interdigitations.
Therefore, the therapeutic decision in the face of maxillary endognathism will depend on the histological stage of the suture:
- In the infantile phase (which generally coincides with the temporary dentition and the formation of the mixed dentition):
– An etiological treatment (morphofunctional rehabilitation) may be sufficient to correct this endognathism by creating a favorable environment for harmonious transverse maxillary growth.
– Treated in the primary dentition, the correction is very rapid because the narrowness of the upper jaw is generally only very moderate. A maxillary disjunction is not necessary at this age, gentle forces will be largely sufficient (quadhelix).
- In the juvenile phase (mixed and adolescent dentition):
- At the mixed dentition stage, the midpalatal suture retains all of its growth potential in response to physiological demands linked to the growth of the facial mass and orthopedic stimulation.
- At this stage, treatment of maxillary endognathism requires an orthopedic phase which can be done with a disjunct, the aim of which is to separate the right and left maxillae by opening the midpalatal suture.
The circuit breaker:
Orthopedic palatal expansion (OPE) was first described in 1860 by Angell in a case report.
- The main circuit breakers vary depending on their anchoring:
Dental support:
- The Haas 4-ring circuit breaker;
- The 2-ring Scheidman circuit breaker;
- The circuit breaker on the glass ionomer sealed gutter.
Bone-supported
The bone-supported breaker with an implant-supported Hyrax screw: the DresdenDistractor (DD) or Dresden Distractor.
- Activation of the circuit breaker: There are three possibilities for expansion:
– ultra-rapid maxillary disjunction in 3 sessions, with pre-medication and under local anesthesia to obtain an expansion of 6 to 9 mm.
– semi-rapid maxillary disjunction, performed in 3 weeks, therefore a little longer but less traumatic than the previous one,
– slow maxillary disjunction over 3 months.
- The effects of the circuit breaker:
Alveolo-dental effects:
- Opening of an inter-incisi diastema;
– an increase in the arch perimeter, which can be calculated from the initial width (L), determined after disjunction between the 1st premolars and is equal to 0.7 x L.
– Excessive forces can cause, according to Henry, alveolar microfractures, vascular distension and inflammation of the soft tissues surrounding the suture site.
Skeletal effects:
According to Da Silva, at this age, we would obtain an increase in the width of the anterior part of the maxillary arch and the nasal cavity which are at the origin of functional repercussions leading to a modification of the morphology of the nose, allowing a nostril symmetrization.
At the nasal level, this remodeling leads to locoregional modifications:
– a lowering of the nasal floor
– straightening of the nasal septum
– widening of the nasal cavity from 2.5 mm to 5.5 mm
Effects on muscular and functional balance:
- All studies note an improvement in nasal breathing by widening the floor of the nasal cavities, the lower part of which corresponds to the respiratory zone and the upper part to the olfactory zone.
Treatment of transverse alveolar and basal anomalies
- In adult phase:
In skeletally mature individuals, orthopedic expansion of the maxilla is unsuccessful. The recommended approach for the treatment of maxillary endognathism in such patients is surgically assisted rapid palatal expansion (SRAP).
EPRAC is actually a palatal expansion performed using a conventional dental or bone anchored device, but requiring a prior surgical phase in order to release the areas of the craniofacial massif causing resistance to the expansion forces. Moreover, this type of treatment is considered a form of distraction osteogenesis.
EPRAC is not the only treatment option for the correction of maxillary endognathia in an adult patient. The other frequently used treatment alternative is the segmented Lefort I osteotomy.
5.2. Treatment of mandibular endognathism:
Much more recently, mandibular symphyseal distraction osteogenesis has been proposed as a treatment for mandibular transverse insufficiency associated with significant anterior crowding.
The clinical protocol is divided into three phases:
- Fitting a distraction device: There are three types of devices to widen the mandible:
– dental-supported: placed most often lingually but also more rarely vestibularly. This may be a Hyrax® type jack welded onto 4 rings;
– with bone support: submucosal and placed vestibularly;
– combined (bone and dental support): this can be a Hyrax type jack.
- Symphyseal surgery: The osteotomy line is most often located between the central incisors ;
- Post-surgical orthodontics.
5.3. Treatment of bimaxillary endognathia:
In the presence of transverse insufficiency of the maxillary and mandibular structures, treatment will include one of the alternatives mentioned for the treatment of maxillary endognathism associated with symphyseal distraction in the mandible.
5.4. Treatment of mandibular laterognathia:
In this case, orthopedic and orthodontic treatments are never sufficient; they should never cause dento-alveolar compensations aimed at reducing the malformation; their objective is to make the two arches congruent for the surgical treatment with which they will be associated.
Surgery is specific to each type of laterodysmorphosis and can occur at different levels of the mandible: condyle, neck of the condyle, ascending branch, horizontal branch, mental symphysis.
In the case of excessive laterognathia (case of unilateral hypercondylia ), for Delaire , condylectomy is the indication of choice regardless of the age of the subject; a functional neocondyle will then reform, treatment must be undertaken as soon as the diagnosis is established and regardless of the age of the patient.
In cases of laterognathia due to insufficiency (case of unilateral hypocondylia), the most frequently used surgery consists of lengthening the ascending branch around puberty to symmetrize the mandible and avoid the appearance of secondary deformations at the level of the face.
6. Stability and containment of transverse dimension treatments
Treatment of transverse anomalies consists of orthodontic, orthopedic or surgical expansion action. Post-therapeutic mechanical retention and functional education help prevent the recurrence of these anomalies and hope for long-term treatment success.
Some others, including Alpiner and Beaver, recommend over-correcting by one third of the expansion needed to anticipate recurrence.
It is imperative to maintain retention after distraction for a period of 4 weeks to 3 months.
Most teams wait for radiographic confirmation of bone callus calcification before removing the device.
When the expander is removed, 5 to 6 months after the end of the expansion, a transpalatal arch or removable quadhelix is placed to contain the expansion that has occurred.
7. Conclusion
Transverse malocclusions are the most common malocclusions.
Early management of these anomalies allows, through simple, rapid and effective treatments, to avoid the onset or worsening of these dysmorphias, to considerably reduce the duration of subsequent treatment and to be certain of the aesthetic and functional result.
By this early treatment, the orthodontist will create in the child a favorable environment for harmonious transverse growth, whereas if he intervenes late he will only be able to correct the consequences of unfavorable growth that has already been completed.
In complex malocclusions which combine anomalies in the different spatial directions, the reestablishment of good transverse relationships is the primary objective to allow unlocking of the occlusion which is essential for the other therapeutic phases.
Good oral hygiene is essential to prevent cavities and gum disease.
Regular scaling at the dentist helps remove plaque and maintain a healthy mouth.
Dental implant placement is a long-term solution to replace a missing tooth.
Dental X-rays help diagnose problems that are invisible to the naked eye, such as tooth decay.
The dentist uses local anesthesia to minimize pain during dental treatment.