A. Korrodi Ritto DDS, PhD

The Ritto appliance is a fixed functional appliance that can be described as a miniaturized telescopic device. It has been developed over an 11-year period with the goal of creating a versatile and efficient appliance with an intra-oral simplified application.

Over the last ten years, the author tested more than 15 fixed functional appliances, put the advantages of the various systems to good use while eliminating their drawbacks and managed to bring the best of these devices together into one single appliance.

Before the final model was decided upon, 12 different designs were drawn up and tested. Furthermore, several types of materials and thicknesses were experimented with.

The Ritto Appliance is a one-piece device with telescopic action. (Fig. 1) It comes in a single format, which allows it to be used on both sides. This design means that stock can be kept at minimum levels.

Fig. 1

 

The design of the Ritto appliance permits rapid and easy insertion. After the clinic is familiar with procedure, it is possible to fit the appliance in about 5 minutes and it can be removed in less than half that time. Arches can then quickly be replaced when necessary.

Unlike other appliances it has been designed in such a way that it does not disengage after reaching maximum extension.

Fixing accessories consist of a steel ball pin (to fix the appliance to the upper arch) and a lock controlled sliding brake (which also serves to activate the appliance on the lower arch). (Fig. 2, 3)

Fig. 2	Fig. 3

The versatility of the Ritto appliance means that it can be used in a great variety of clinical situations: in Class I, II div. 1 and 2, or III malocclusions, and also as a complementary measure in the recapture of the articular disc.

Its main application is in Class II with mandibular deficiency, in mixed or permanent dentition, when mandibular advance is required as a way of stimulating growth and reducing skeletal defects.

Additionally, in Class I and II malocclusions, the appliance can be used as an anchorage reinforcement in treatment requiring extraction during the retraction of anterior teeth, in treatment not requiring extraction when interproximal dental remodeling is planned, or in some cases of mandibular asymmetry.

With the same purpose in mind, it can be used for adults undertaking treatment with lingual or vestibular techniques.

It has an important role in malocclusions treated with upper and lower extractions, allowing an advance of the lower molars thus avoiding the retraction of the anterior mandibular teeth.

In certain Class III cases, it is possible to carry out the advance of the upper anterior teeth using a slightly modified version of this appliance.

The Ritto appliance does not require any laboratory stage, which means a reduction in both time and costs. Nor does it require any prior measurement due to the manner in which it is activated. Preparation of the lower arch is the only pre-fitting procedure suggested by the author.

The lower arch has to be prepared before insertion. The thickness and type of arch is chosen, its length is adjusted, locks are fitted and the Ritto appliance is then inserted (fig 4-6).

Fig. 4	Fig. 5	Fig. 6

The lower arch must always remain bent behind the molars so that protrusion of the lower incisors is avoided. It is necessary to first bend behind one molar, seat into the brackets, then slide the arch to the other side so that the first post-molar bend is tight against the slot, then finally bend from the other side as close as possible to the tube. This creates a snugly fitting archwire with minimal risk of sliding.(Fig. 7, 8).

Fig. 7	Fig. 8

Upper insertion is achieved by placing a steel ball ended wire into the .045" headgear tube and bending it gingivally and distally over the attachment. (Fig. 9, 10)

Fig. 9	Fig. 10

In the majority of cases (mixed or permanent dentition) two upper bands and two lower bands (or bonded tubes) and 4 or 6 brackets in the lower anterior teeth are enough to support the appliance.

This is a simplified process resulting in reduced fitting time and easier adaptation for the patient.(Fig. 11)

Fig. 11

I would advise the use of a .017 x .025¨S.S. arch on a .018¨ brackets system, or .018¨x .025¨ S.S. on a .022¨ system, however .016"x.016" SS or a .016" x .022" SS respectively can be used.

A rigid .036¨ SS lower arch is another solution in order to obtain a unit that is resistant to breakage. This solution is important in cases where a frequent breakage of archwires has been a problem, or when significant mandibular advancement is required at the beginning of treatment. With this arch, activation is carried by means of a steel ring instead of a sliding lock. The ring is cut with a drill, opened out, placed into the .036" arch and adjusted with Howe pliers. (Fig. 12)

Fig. 12

Activation

Activation is achieved by sliding the lock along the lower arch in the distal direction and then fixing it against the Ritto appliance. (Fig. 13 - 18) When working with a rigid arch, the steel rings have to be measured to carry out the planned advance.

Fig. 13	Fig. 14	Fig. 15
Fig. 16	Fig. 17	Fig. 18

For those who are not familiar with this kind of therapy, I would advise progressive activation, which will be dependent on the severity of the malocclusion, treatment stage and above all on good clinical sense (acquired experience and knowledge of the patient).

The plan that should be followed when unfamiliar with the appliance is as follows:

• For the first week the patient merely has the appliance fitted, i.e. without forced mandibular advance. This is the adaptation stage.
• In the second week the appliance is activated 2 to 3 mm. This is known as the adjustment stage, where the lower support system (lower arch) adapts to the pressure exercised by the activation and opening and lateral movements carried out.
• In the third week the activation stage is started. The degree of mandibular advance is dependent on the number of contacts in forced protrusion (the more there are the better the adaptation) and on the severity of the malocclusion (when the initial overjet discrepancy is extreme, total advancement should not be attempted in one step, because of the exaggerated stress placed upon the support systems and the demands of adaptation placed upon the patient).

On average, an activation of 4 to 5 mm is carried out, repeated three weeks later.

In summary, a slight activation is carried out in the beginning which is then progressively increased during treatment and adaptation.

In my opinion, to know if the patient is a candidate it is important to do a facial aesthetic analysis by a photographic study and through direct evaluation, an occlusion analysis and a cephalometric analysis.

There are 5 important points:

Type of malocclusion – The patient should present a Class II division 1 malocclusion with mandibular deficiency and an overjet over 6 mm. The candidate should still be growing, and be in transition from mixed to permanent dentition (Fig. 19 – 20).

Fig. 19	Fig. 20

Dental contacts – It is important to check how many posterior contacts we find with the mandible in Class I (more contacts in the posterior area, better adaptation). Intra-orally we can find if it necessary to correct vertical or transversal problems before mandible advancement and consider the severity of the case, and finally check the size of the cuspids. Dental abrasion is not good for final stability (Fig. 21- 22).

Fig. 21	Fig. 22

Facial Profile - The patient is asked to advance the mandible to Class I, then it is checked to see if there is profile improvement. This check should be carried out with the lips in contact and at rest (Fig. 23 – 28).

Fig. 23	Fig. 24	Fig. 25
Fig. 26	Fig. 27	Fig. 28

Muscular Elasticity - good muscular elasticity can be appreciated when the patient is asked to advance his or her mandible with lips touching. In these cases, there is no great muscular contraction. Another manner of checking this is with the lip retractors when intra-oral photographs are taken. If elasticity is good then the first molars and sometimes even second molars will be seen (Fig.29).

Fig. 29

These patients demonstrate greater adaptation ability.

Co-operative ability - despite being a fixed appliance, co-operation is important throughout the whole treatment process. The explanation given to parents about correction usually encourages responses about their child's behavior (if they are careful, obedient, etc).

We often hear negative opinions from colleagues who have tried fixed functional appliances unsuccessfully. Breakage is pointed to as the most common cause for dissatisfaction. After one bad experience, some orthodontists are unwilling to try again and harbor a great dislike of this form of treatment.

The keys to success have never been properly described but they are essential in order to keep the patient motivated and focussed. When they are properly followed, the risk of breakage is considerably reduced.

1^st key - The choice of patient is fundamental however, it is always possible to make a bad judgement (see choice of patient).

2^nd key - After the orthodontic stage (with the arches coordinated), the patient should use a mini stimulator for mandibular advance for two months. (Fig. 30-32)

Fig. 30	Fig. 31	Fig. 32

This appliance is simply a thermo-formed retainer, 0.7 mm thick, which is placed onto the upper incisors. It has an acrylic bite block in its palatine area which fits into the lower incisors. The acrylic block is constructed with the mandible advanced in Class I.

It is explained to the patient and parents exactly what should be done during this period, i.e. which exercises should be done, the position which should be memorized and the reasoning behind this stage (to avoid too great a pressure, fracture and vestibular inclination of the lower incisors when the fixed functional appliance is fitted).

In the first month, there will be some muscular stimulation and adaptation by the patient to the new position. In the second month, the patient should execute deglutition exercises with the mandible advanced and with the lower incisors in the acrylic bite block. At the end of this stage it is quite common for some labial contact ability to be apparent without muscular contraction. It can be used also in the first stage of the Ritto appliance therapy (Fig.33 – 45).

Fig. 33	Fig. 34
Fig. 35	Fig. 36	Fig. 37
Fig. 38	Fig. 39
Fig. 40	Fig. 41	Fig. 42
Fig. 43	Fig. 44	Fig. 45

3^rd key - Arch co-ordination must be done so that when the mandible is advanced, the maximum number possible of posterior contacts is obtained.

These contacts provide stability, comfort when chewing and help achieve faster adaptation. It is through the initial orthodontic stage that the necessary leveling out is done.

The modification of such a patient's profile is a tremendous challenge to the orthodontist, but there is great satisfaction in seeing successful treatment.

The treatment basically consists of the forced and prolonged advance of the mandible. This therapy allows growth to be stimulated so as to harmonize skeletal defect and soft tissues, immediately change facial expression and smile, remove abnormal muscular habits, establish labial competence, increase the space for the tongue, reduce or eliminate the need for orthognathic surgery and obtain a functional Class I occlusion.

References

Ritto A. K. Aparelhos funcionais fixos – novidades para o próximo século. Ortodontia 1998 Vol III nş2: 124 – 150.

Ritto A.K. El aparato de Ritto – colocacion e activacion. Accepted for publication in Ortodoncia Clinica Nş2 Vol.2 1999.

Ritto A.K. Fixed functional appliances – new trends for the next century. Accepted for publication in The Functional Orthodontist Vol 16 Nş2 1999.

A. Korrodi Ritto D.D.S., Ph.D. is in the private pratice of orthodontics at 115 Mouzinho Albuquerque, 2400 Leiria, Portugal.