Treatment of dental agenesis

Treatment of dental agenesis

Dental agenesis is an anomaly frequently encountered in orthodontics.

They mainly affect the end of series teeth:

• The second mandibular premolars;
• The maxillary lateral incisors;
• The second maxillary premolars.
• Wisdom teeth;

Agenesis can be uni- or bilateral.

The treatment of dental agenesis requires the practitioner to make a difficult choice between a closure solution, mainly orthodontic, and a solution of replacing the missing tooth with a prosthesis requiring multidisciplinary treatment.

1. AGENESIS OF THE LATERAL INCISOR:

It is agenesis that poses the most delicate problem because of the location of the lateral incisor in the arch and its functional and aesthetic role.

1. Selection criteria:

The practitioner must choose between:

• A so-called substitution solution by closing the agenesis space, the canine then playing the role of lateral incisor and the first premolar that of canine;
• a replacement solution with a prosthetic element. The prosthetic reconstruction is carried out using an implant-supported crown, a bonded bridge, exceptionally a conventional bridge or a cantilever bridge.

2. Therapy itself:
   1. SUBSTITUTION SOLUTION: (closure of the agenesis space)
3. Benefits :
   • It ensures definitive compensation for agenesis from adolescence only through orthodontic treatment (it avoids prosthetics).
   • It is relatively economical in dental tissue (simple coronoplasty most often).
   • It gives full satisfaction to the patient on an aesthetic level:
   • Its cost is lower.
4. Disadvantages
   • Risk of profile modification: (consequences of incisor retraction)
   • Smile disturbance
   • Decreased support of the nasolabial fold which sags slightly in

relationship with mesialization of the canine hump;

• Dynamic occlusion is disturbed by mesial displacement of the canine.
• The palatal cusp of the first premolar can induce occlusal interferences

3. General principles of orthodontic replacement treatment:

The treatment consists of mesializing the canine in contact with the central incisor

Closure of the residual space distal to the canine is ensured by mesialization

of the posterior sector or incisorcanine retraction depending on the type of occlusion.

The end-of-treatment occlusal objective depends on compensatory extractions

possible in the mandibular arch:

• Without extractions in the mandibular arch: the end-of-treatment occlusion is a molar class II and canine class II occlusion.
• With extractions of premolars in the mandibular arch: the end occlusion of

treatment is a class I molar and class II canine occlusion.

Adjustments at the canine level:

1. Adaptation of the height of the collars: the treatment must result in a position of the

canine slightly extruded in order to align its neck with that of the central incisor.

2. Morphological transformation: A coronoplasty is necessary to make the canine resemble a lateral incisor and ensure correct occlusal function.

Adjustments at the level of the first premolar:

• Slight extrusion of the premolar and possible gingivoplasty:
• Increase in root-vestibular torque on the first premolar:
• Grinding of the palatal cusp.

3.2. REPLACEMENT SOLUTION: (opening or maintaining the agenesis space)

1. Advantage :

• This solution has the advantage of restoring the continuity of the arch and its symmetry.
• Avoids the effects of incisor retraction on the profile.

2. Disadvantages:

• Requires the intervention of a multidisciplinary team
• the aesthetic result is random because it is very dependent on the quality of the prosthesis produced.
• It is also more expensive for the patient.

3. Different prosthetic solutions:

We will always seek the least damaging solution for the dental system. Thus, conventional bridges, which are too damaging, are currently reserved for

patients with carious or traumatic damage to the central incisors and canines.

The recommended prosthetic reconstructions are therefore:

• implant-supported single crowns
• bonded bridges.

1. Implant solution

It ensures total respect for dental integrity and has very high success rates,

However, it requires several steps.

In adolescents, it is essential to wait until the end of growth to place the implant.

which imposes a long transitional containment phase.

2. Replacement solution using a bonded bridge:
   • It restores the patient’s occlusal function and aesthetics more quickly
   • Can be implemented earlier.
   • Saves dental tissue

On the other hand: the metal framework of the bridge can give off grayish reflections through the transparency of the dental tissues.

This solution is contraindicated in cases of overbite and especially bruxism.

4. Orthodontic and prosthetic treatment:

Orthodontic treatment involves opening the space of the agenetic incisor by distalizing the canine and bringing the central incisors closer together if they are separated.

The opening of this space is generally achieved using compressed nickel-titanium springs.

At the coronary level and in order to determine the space necessary for the future lateral, several methods can be used:

• Either adopt the dimensions of the contralateral tooth if it exists.
• In the case of bilateral agenesis: the lateral incisor must then measure two-thirds of the mesiodistal diameter of the central incisor (6 mm for example when the central incisor measures 9 mm);

At the root level: orthodontic treatment must ensure a certain divergence between the root of the central incisor and that of the canine to allow the positioning of the future implant without risk of root contact.

Finally, a retainer must be put in place while waiting for the future implant to be fitted.

2. AGENESIS OF THE SECOND MANDIBULAR PREMOLAR.

As in the case of lateral incisor agenesis, the practitioner is faced with the choice of closing or opening the space or maintaining it for possible prosthetic restoration.

Selection criteria:

The essential selection criterion here is the presence or absence of disharmony.

dentomaxillary requiring extractions.

• Solution 1: Closure of agenesis spaces

It is similar to treatment with premolar extractions. At the occlusal level, in the absence of compensatory extractions in the maxillary arch, occlusal equilibration must be carried out to create a Class III occlusion.

• Solution 2: Maintenance of the temporary tooth and prosthetic solution:

The long-term solution is to install an implant. Traditional bridges are too damaging to adjacent teeth.

The retention of the temporary tooth maintains the alveolar bone at the future implantation site and acts as a space maintainer. It is therefore advisable to keep it until the implant is placed.

3. MULTIPLE AGENESIES

In cases of multiple agenesis, the consequences are more severe and the

Therapeutic treatment is most often implanted at the end of growth.

The absence of several permanent teeth requires in most cases prosthetic restoration with implant-supported prostheses.

Temporary teeth are kept as long as possible to maintain the bone

alveolar.

However, the aesthetic damage can be significant, requiring the creation of temporary prosthetic devices (removable prosthesis) to give the young patient an acceptable smile during their adolescence.

Orthodontic treatment must be part of a multidisciplinary approach.

Everything must be done to facilitate prosthetic production:

• By monitoring growth and intercepting possible skeletal shifts;
• By rehabilitating functions that may be disrupted by missing teeth;
• By preserving as much available alveolar bone as possible;
• By distributing the permanent teeth as best as possible within the framework of the prosthetic project.

Conclusion :

The treatment of dental agenesis is not simple and offers the practitioner several therapeutic possibilities , the choice of which will be made through the analysis of several parameters such as the age of consultation, the presence or absence of dento- maxillary disharmony as well as the profile.

The practitioner must therefore be able to recognize the signs of probable agenesis in order to initiate therapy as soon as possible to restore the aesthetics but also and above all the occlusal function of the missing tooth.

Treatment of dental agenesis

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Treatment of dental agenesis