Class II treatment

Class II treatment

 1.Introduction 

Class II malocclusions represent the most frequently encountered dento-skeletal anomaly during our consultations, and Angle has distinguished two entities: class II division 1 and class II division 2.

             Treating class II dysmorphia requires a thorough diagnosis and a precise therapeutic approach. For this reason, any orthodontic correction must take into account several parameters: the type, location, intensity of the dysmorphia, but also the age and motivation of the patient.

2. Generalities 

1. Definition : 

• Stallard: “When, for one reason or another, the lower first molar erupts behind its normal position, and when this mal-eruption reaches or exceeds the width of a cusp on each side, the result is that all the permanent teeth subsequently erupting in the lower arch have a distal position. This is Class II malocclusion.”
• Angle distinguishes two divisions:

• Division 1 is characterized by a narrowed upper arch with vestibuloversion of the upper incisors, short lips, the lower lip interposed between the upper and lower incisors; the chin is recessed.
• In division 2, the arch has a normal width, in addition, there is a palatoversion of the incisors associated with the overbite.

2. Clinical forms: 

In class II malocclusions, we distinguish 4 clinical forms which can be isolated or associated: brachymandibulia, retromandibulia, dolichomaxillia, promaxillia.  

3. Class II treatment 

3.1. Factors influencing the therapeutic choice:

The choice of the therapeutic attitude to adopt must take into account several parameters: 

• Dental age: Estimated on a panoramic radiograph. Some devices are applied in stable mixed dentition such as extraoral forces on splints and others at the time of the evolution of the upper premolars such as extraoral forces on bands.
• Growth stage: It is useful to situate the patient on his growth curve either to take advantage of the maximum growth rate preceding the pubertal peak, or to postpone treatment until after the growth peak. 

According to BJORK’s height growth curve

Adolescent period From 10-11 to 15-16 years; orthopedic treatment and fixed orthodontic treatment

Adult period: from 18 years old; Fixed orthodontic treatment and/or surgical treatment

• Growth type: A horizontal growth direction is consistent with the treatment goal. A vertical growth direction causes effects opposite to the treatment goals.
• The severity of the anomaly: the more severe the anomaly, the earlier the treatment should be, or the more radical and therefore surgical at the end of growth. 
• Motivation for treatment: Class II treatment requires good cooperation in wearing (FEB, TIM), otherwise it is better to opt for extractions
• The position of the lower incisor: if the lower incisor is vestibular, contraindication to the use of TIM and activators.

3.2. Time of processing: 

The timing of initiation of treatment for Class II Division 1 can be either early or late.

3.2.1. Early treatment: 

3.2.2. Late processing: 

5. Treatment of class II division 1

5.1. Purposes of processing:

5.1.1. Skeletal objectives:

• Slow down maxillary growth.
• Stimulate mandibular growth.
• Decrease skeletal convexity.
• Improve DV.

5.1.2. Occlusal objectives:

• Obtain a Class I canine and molar Angle or a therapeutic Class II molar
• A correct angle of attack.
• Correct the DDM if it exists. 

5.1.3. Aesthetic objectives:

• Improve aesthetics: reduce convexity.
• Achieving correct lip relations.
• Achieve lip occlusion at rest without involvement of the chin tuft muscles.

5.1.4. Functional objectives:

• Remove parafunctions (tics and distorting habits).
• Swallowing rehabilitation.
• Restoration of purely nasal ventilation.
• Rehabilitation of the musculature.
• Facilitate mandibular propulsion and diduction movements.

5.2. Means of processing:

5.2.1. In infants: 

Davis et al. demonstrated a highly significant relationship between bottle feeding and malocclusions in the anteroposterior direction.

He concludes that exclusive bottle-feeding is an important cause of class II

So for the Newborn you need:

• Favor physiological feeding (at the breast): in the orthostatic position (which forces the infant to move the mandible forward)
• Active monitoring of nasal ventilation maintenance: rigorous hygiene of the upper respiratory tract.
• Laying infants on their sides, not in the ventral position, promotes mouth breathing and the persistence of neonatal mandibular retrognathism. This position also reduces the risk of sudden infant death.

5.2.2. In temporary and mixed dentition:

        5.2.2.1. Myotherapy: 

It is a gymnastics aimed at increasing muscular power, and improving the function of certain deficient muscles.

• Mandible thruster gymnastics:

In the case of retrognathia: Voluntarily and slowly move the mandible forward as much as possible and keep it propelled for 10 seconds, the movement should be repeated 10 times. 

Class II treatment

• Labial muscle gymnastics: 

To correct labial hypotonicity causing upper alveolus.                                                                                                     

2. Functional therapy: through the use of CNM rehabilitation devices

• The vestibular buccal screen: The lower incisors come into contact with the stop, thus preventing the appliance from tilting, while repositioning the mandible forward and facilitating lip closure. Thus, from the age of 3, the pacifier can be replaced by the EBV by encouraging the child’s adhesion
• Bruno Bonnet’s nocturnal lingual envelope: Allows the rehabilitation of a pathological lingual posture “high and forward position of the tongue” in favor of a class II div 1, by offering the tongue a new physiological posture, the latter becoming an orthopedic device and allowing the rebalancing of the CHATEAU corridor.

3. Orthopedic therapy: 

• Class II with maxillary liability
• Extraoral forces

Used to slow down maxillary growth, the intensity of the elastic traction is proportional to the extent of the slowdown in maxillary growth.

Regarding the control of the vertical direction, depending on the settings of the external branches of the facebow, it is possible to control the palatal plane and the occlusal plane.

– For a deepbite facial typology: low traction

– For an openbite facial typology: high traction.

– For a normobite facial typology: oblique traction.

However, the use of extraoral forces has the following disadvantages:

– It reduces patient comfort and requires significant cooperation, as wearing an extra-oral appliance 14 hours a day constitutes a significant daily constraint and requires significant orthodontic forces.

• Class II with mandibular responsibility
• Cl II activators

The use of functional orthopedic devices is a therapeutic approach frequently used in the correction of class II division 1 malocclusions with deepbite typology.

Mode of action:

The propulsion position causes contraction of the lateral pterygoid muscles, which stimulates activity of the mandibular growth centers.

This position also causes tension in the retropulsor muscles. This causes an inverse force of mandibular recoil which is transmitted, via the activator, to the maxilla which is thus slowed in its sagittal growth.

Thus, the orthopedic action of the activator is summarized in a stimulation of mandibular growth and a braking of maxillary growth.

In addition, there is an orthodontic action due to the drawer effect:

• the maxillary arch, as a whole, tends to tilt distally with palatoversion of the maxillary incisors 

• the mandibular arch, as a whole, tends to tilt mesially with vestibuloversion of the mandibular incisors.

• The Distal Active Concept (DAC) is a technique for distalization of maxillary molars that has a marked orthopedic effect on mandibular growth. It was developed by Dr. Aknin and presented in 1995 for Cl II with mandibular responsibility.

Class II treatment

1. The CIV wedge allows the unlocking and repositioning of the mandibular condyle allowing the activation of the mandibular growth center.
2. The double elastic of the TIM of cl II allows canine retraction and incisor contraction
3. The compressed spring allows the distalization of the 6, and activates the tuberosity growth of the maxilla.

Class II Dual Liability 

“Activator association – extraoral force”

Hasund was the first to describe the use of an activator in combination with an extraoral force. This combination can be used both for vertical control and to increase the growth-braking action of the maxillary.

It can also be indicated in cases of class II with maxillary predominance with an unfavorable mandibular growth pattern (slight posterior rotation). The direction of traction is high with cranial support by occipito-parietal helmet.

5.2.3. In young adult teeth 

• Before the end of growth, we treat as a patient with mixed dentition.
• After the end of growth, we treat as a patient with full adult dentition. 

3. In full adult dentition 
4. Orthodontic therapy

• In the presence of a long face, treatment requires the use of extractions; the choice of teeth to be extracted depends on the desired end-of-treatment objective.

• Extraction of 14/24;
• Extraction of 14/24 and/35/45;
• Extraction of 14/24 and 34/44; in the presence of associated biproalveolism or DDM.
• Extraction of 16/26. 

Class II treatment

• In the presence of a short face , in the presence of a minor base shift, the correction is made using: class II TIMs or distalization by miniscrews without resorting to extractions.

In the presence of a significant discrepancy, extractions are necessary, they are uni-maxillary (14/24), to avoid aggravating the deepbite typology.

2. Surgical therapy:

It is required each time that:

•The severity of skeletal dysmorphosis exceeds orthodontic possibilities;

•The patient’s age no longer allows us to hope for favorable growth and dento-alveolar movements, even significant ones, cannot compensate for skeletal deficiencies or excesses;

• The duration of orthodontic treatment is often a barrier to adult motivation, but surgery can represent a quicker solution.

The surgical techniques used are:

Le Fort I maxillary setback osteotomy;

Obwegeser-DalPont osteotomy   for mandibular advancement;

The retrocondylar wedge for mandibular advancement;

 Genioplasty.  

5.3. Contention:

After early treatment keep the activator in place

After late treatment: Hawley plaque

                                Tooth positioner

Fixed retention on the lower arch: twisted wire glued to the lingual surfaces from 33 to 43

6. Treatment of class II division 2

Class II division 2 is a dento-skeletal anomaly characterized by distal occlusion of the mandibular lateral sectors, with inversion of the sagittal molar relationships, and by linguoversion of the upper central incisors and sometimes of the lateral ones as well as an incisor overbite.

Class II treatment

6.1. Purposes of processing:

6.1.1. Skeletal objectives:

• Do not move point A back;
• Correct the Class II base shift by inhibiting maxillary growth and stimulating mandibular growth.

6.1.2. Occlusal objectives:

• Lifting the incisal lock by placing the apices of the upper incisors in the palatal position and closing the angle of attack;
•  Ensure a satisfactory incisal guide according to the incisal slope;
•  Correct Class II occlusal relationships to achieve Class I molar and canine angles. 

6.1.3. Aesthetic objectives:

• Do not modify a straight profile;
• Correct a concave profile;
• Improve facial typology.

5.1.4. Functional objectives:

• Remove parafunctions (tics and distorting habits).
• Swallowing rehabilitation.
• Restoration of purely nasal ventilation.
• Rehabilitation of the musculature.
• Facilitate mandibular propulsion and diduction movements.

6.1. Means of processing:

6.2.1. In infants: 

Preventive treatment in nursing remains the same as that for preventing Class II Division 1 malocclusion.

 For the Newborn it is necessary:

• Favor physiological feeding (at the breast), in an orthostatic position.
• Active monitoring of ventilation maintenance.
• Place infants on their side.
• Encourage a hard diet after the eruption of baby teeth.

6.2.2. In temporary dentition:

 The treatment is preventive  : J. PHILIPPE prevents the appearance of supra-alveoli between 4-5 years:

• Selective grinding of temporary canines: to balance lateral movements and occlusion in propulsion.
• Inter-incisor plate: after loss of the temporary central incisors.
• Myotherapy: lip relaxation exercises 
• Functional rehabilitation therapy: vestibular screens, HINZ or MUPPY pacifier, nocturnal lingual envelope. 

                                                              HINZ’s lollipop

6.2.3. In mixed dentition:

• Removable orthodontic therapy : a palatal plate with an omega hook or a posterior-anterior acting jack to unlock the occlusion anteriorly followed by correction of the overbite by  : 

• Ricketts’ incisive base arc of intrusion;
• FEB high traction on gutter;
• FEB low traction on molar ring;
• Retroincisive plane.
• Orthopedic treatment to correct the base shift, the choice of device of which depends on the clinical form. 

• Low amplitude shift: Unlocking the occlusion and acquiring muscular balance may be sufficient.
• Significant shift:  

• FEB ;
• Class II activators;
• DAC; 
• Class II activators associated with high traction FEBs  

6.2.4. In adult teeth:

• Lifting the anterior lock by correcting the axes of the incisors of the overbite;
• fixed orthodontic therapy 

• Without extraction: Class II intermaxillary traction (IMT: upper canine to lower molar)
• With extraction: If the correction of the discrepancy is insufficient or associated with the presence of DDM, the extraction must be mono-maxillary to avoid aggravating the deepbite typology.

Class II treatment

Surgical treatment:

• Sagittal osteotomy for mandibular advancement.
• Mandibular advancement by retrocondylar cartilaginous wedge
• Genioplasty: surgery that allows chin plastic surgery  

6.3. Contention:

• The ideal retention is the positioning splint (Tooth positioner)
• Sved plate for overbite 
• Hawlay Plate

7. Prognosis

Depends on:

• Timing of treatment: early management of these cL II anomalies is necessary; it simplifies overall treatment by reducing the need for extraction and by reducing the duration of multi-band treatment;

• Patient cooperation 
• Severity of the abnormality and the degree of bone base shift
• Hereditary nature of dysmorphosis: the prognosis is rather good in the case of dysfunctional class II 

8. Conclusion

Given the variability of clinical forms of Class II malocclusions and their etiologies, the orthodontist must take into account 3 parameters: the patient’s preferences and behavior, current scientific data, the condition as well as the clinical circumstances in order to establish an adequate treatment plan.

            So whatever the choice made and the technique used, the practitioner must:

• Use your clinical sense.
• Sufficiently master your therapeutic methods to allow your patient to regain functional occlusion and improved facial aesthetics.
• 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. 
• Teeth whitening is an aesthetic procedure that lightens the shade of teeth while respecting their health.
• A consultation with the dentist every six months is recommended for preventive and personalized monitoring.
• The dentist uses local anesthesia to minimize pain during dental treatment.

Class II treatment