Treatment of Class III anomalies
Introduction :
Class III anomalies are characterized by often severe aesthetic damage and a potential for late progression, linked to residual growth of the mandible. Which in certain cases leads to orthodontic-surgical therapy.
- Class III processing time:
In the vast majority of cases, therapeutic intervention is early in order to restore the incisor key as soon as possible and to normalize functions to favorably guide growth.
It reduces aesthetic damage during growth, providing the child with psychological benefits. Orthopedics can be started from 4 or 5 years old, or even earlier.
The ideal period is the temporary dentition. It is necessary to treat as soon as the child is seen.
After 13-14 years , it does not seem that maxillary actions can be obtained. Alveolar adaptations will usually be obtained.
These are drawer movements of the alveolar processes.
- Prevention and interception of classes III:
- normalize the functional matrix,
- remove dental interferences
- correct kinetic disorders.
- Reestablishment of incisal occlusion to normalize further growth is essential.
- Action on the functional matrix
Establishment of normal functional orofacial behaviors as early as possible :
- nasal ventilation;
- eating behaviors requiring sufficient muscular activity
- normalize language position and behaviors
- correct the low and anterior position of the tongue.
If Ankyloglossia: lingual frenectomy with rehabilitation
Parafunctions favoring class III must be removed:
- nail biting;
- sulky attitude;
- digital suction with traction on the mandible.
- Correction of a reverse incisor occlusion
Dentally induced reverse or end-to-end incisor occlusions should be corrected as soon as possible.
- palatine plate with pushers or vestibular springs;
- removable mandibular appliance with vestibular bar for lingualizing mandibular vestibular incisors that are overturned with diastemas;
- The ESCHLER headband , vestibular headband applied to the lower incisors
- Crozat quad helix which vestibulates the incisors;
- partial multi-attachment appliance to vestibulate the maxillary incisors or lingualize the mandibular ones.
- Correction of mandibular prolapse:
Mandibular prolapse is a kinetic phenomenon simulating class III but which can evolve into class III.
Its early correction is therefore essential.
- Grinding of temporary canine cusp tips associated with maxillary transverse expansion: When related to occlusal interferences (may be sufficient to restore occlusal stability and prevent prolapse.)
- A class III activator: associated with maxillary transverse expansion.
Treatment of Class III anomalies
- Class III orthopedics
- Mandibular prognathism:
- The occipito-mental sling:
When the child is under 4 years old
It helps to slow down mandibular growth.
The forces should not be too strong.
- Classic anteroposterior extraoral forces:
Can be applied to the mandible; bands are placed on permanent molars or temporary second molars.
Contraindicated in vertical growth types
- Face masks:
- Face masks are particularly indicated in class III due to maxillary retrognathia but constitute for many authors the interceptive device of choice in class III
- For BENAUWT (1978), the Delaire mask is a device of choice which is indicated, even if there is no true maxillary brachygnathia , because it allows to quickly improve the harmony between the bony bases and between the incisors, and to hope thus to reestablish a more balanced growth.
- Maxillary hypodevelopment/retrognathia:
- Face masks
These are extra-oral devices that allow postero-anterior traction to be exerted on the maxilla using elastic tractions.
Results:
At the skeletal level:
An advancement and tilting of the maxilla around the frontomaxillary suture
A maxillary transverse disjunction potentiates the effect of the postero-anterior traction of the mask.
At the dento-alveolar level:
– mesialization of the maxillary arch with vestibuloversion of the incisors,
– a slight molar egression according to the direction of traction;
On an aesthetic level,
Improved lip ratios and reduced facial aplasia.
- Class III orthodontics
Except for the early orthodontic movements aimed at establishing the incisor key already mentioned, orthodontic treatment of Class III is most often carried out in permanent dentition .
The unfavourable influence of residual growth in fact leads to delaying orthodontic treatment in borderline cases, especially if extractions are envisaged.
Correction of Class III occlusion is achieved by:
- a mesialization movement in the maxillary arch;
- a distal movement in the mandibular arch.
Treatment of Class III anomalies
- Class III intermaxillary tractions
Distalization of the mandibular arch and mesialization of the maxillary arch.
Their vertical component causes an egression of the maxillary molar which can lead to a posterior rotation of the mandible.
- Extractions in classes III
When crowding, incisal repositioning or the importance of the occlusal class III requires it, extractions can be performed.
- Extractions of 15- 25- 34- 44
This is the preferred choice in class III because:
- Extractions of 14- 24- 34- 44
They respond more to the problem of anterior maxillary crowding, in particular in cases of included or dystopic canines, and to a lesser need for occlusal adjustment.
They impoverish the volume of the anterior part of the maxilla.
- Extractions only in the mandible from 34-44
This choice of extractions is very controversial and remains exceptional due to its rare indications.
- Wisdom teeth extraction:
In case of recession of the lateral mandibular sectors, extraction of wisdom teeth is most often necessary.
- Surgical-orthodontic treatment of class III
- Indications for surgery
Surgery is intended for patients with:
- a severe skeletal class III that was not or could not be reduced during growth;.
- significant aesthetic damage;
- an associated transverse or vertical anomaly;
- marked alveolar compensations which compromise the possibility of orthodontic treatment.
It is performed outside of growth in order to avoid any risk of postoperative recurrence linked to late mandibular growth, especially in boys.
- Different types of surgeries
- Bone base surgery:
Maxillary surgery:
Mandible surgery
Combined bimaxillary surgery
- Contour surgery: genioplasty and profiloplasty
- Soft tissue surgery
Conclusion
Early orthopedic treatment is the key to the success and simplicity of class III treatment. It should be undertaken as early as possible, as soon as the child is seen. This is how it will give the best results, most often spectacular.
Thus, early interception should make recourse to surgery exceptional.
Treatment of Class III anomalies
Untreated cavities can damage the pulp.
Orthodontics aligns teeth and jaws.
Implants replace missing teeth permanently.
Dental floss removes debris between teeth.
A visit to the dentist every 6 months is recommended.
Fixed bridges replace one or more missing teeth.