Space management in the developing dentition and dental arches

In orthodontics, preserving the space available in the dental arches for the eruption of the permanent teeth is essential during the development of the dentition in order to minimize eruption problems and ensure that teeth erupt in the best possible position.

• The space available in the dental arches is affected by the difference in width of the temporary teeth compared to the width of the permanent teeth. It is all in space! To know more.

Adequate supervision and follow-up by the orthodontist through clinical examination supplemented with radiographs will allow early detection of developmental anomalies and eruption problems. When indicated, certain interventions may be recommended to minimize the possible impact of these problems.

A procedure frequently used in orthodontics to help the eruption of the permanent teeth when space is deficient is to extract certain deciduous (temporary) teeth (serial extractions). Sometimes, it is also indicated to use appliances that maintain space in the preventive and interceptive stages of orthodontic supervision. The space maintainer is an appliance that:

• As the name implies, preserves or maintains the space already available for the eruption of permanent teeth following the extraction or loss of temporary teeth;
• “Holds” in place the permanent teeth already erupted and prevents tooth migration while other teeth complete their eruption;
• Can be prescribed when temporary molars are lost prematurely, are very mobile or need to be extracted to help the eruption of their permanent successors;
• Is a passive appliance that does not perform any corrections. It only ensures that the already available space remains available until the permanent teeth have completely erupted;
• Is not aimed at correcting malposition of teeth, increasing the space available or retrieving lost space (crooked teeth will remain crooked!). Orthodontic corrections with other types of appliances (braces) are usually indicated following the use of a space maintainer;
• Does not correct jaw width or their relationships between them;
• Can be used in the upper or lower jaw;
• Can be a removable appliance (that can be removed by the patient) or fixed (that cannot be removed).
• Making space maintainers only requires taking a dental imprint used to make a model of the dentition on which the appliance will be custom-made in the laboratory;
• Inserting space maintainers in the mouth and wearing them is not painful or uncomfortable when the appliances are well made and adapted to the dentition.

Will a space maintainer “prevent having braces”?

• Using a space maintainer does not guarantee that the teeth that have not erupted yet will do so correctly or that the occlusion (bite) will be adequate once the permanent dentition is completed. Indeed, in most cases, even if such an appliance is used, it must be expected that other teeth will still erupt with significant irregularities or malpositions if the space deficiency was severe to start with. If this were the case, further corrections using corrective appliances (braces) may be necessary to optimize dental function and esthetics. If this is the case, we will inform you in due time about the required procedures and related costs.
• These appliances are often utilized when there is an important lack of space for the eruption of the permanent teeth and when teeth have an abnormal eruption pattern (which is visible on a panoramic radiograph). So using a maintainer has the sole purpose of preserving this space during eruption of teeth instead of creating more space to ensure an eruption without problems.
• The purpose of using space maintainers is thus not “to avoid braces later on” because the problem is already present when this interceptive intervention is performed.

It is important to mention again that the orthodontic supervision while a space maintainer is worn must be considered as a preliminary step aimed at facilitating the eruption of the teeth. This intervention does not move or correct teeth to improve their position or alignment.

Lower space maintainer

• This appliance has two metallic bands placed around the first molars and united by a wire running on the inside (tongue side) surface of the teeth;
• It is a fixed appliance (the bands are cemented on the teeth) and the patient cannot move or remove it himself/herself;
• After a short adaptation period, it does not interfere with speech or mastication.

Fixed upper space maintainer

Sometimes, it may be indicated to use a fixed maintainer rather than a removable one in the maxillary arch. This may be the case when:

• The patient loses a temporary tooth when he/she is very young (7-8 years of age) and the appliance needs to be worn for several years;
• The patient’s cooperation with a removable appliance is questionable. Parents are more suited to evaluate their child’s cooperation and sometimes prefer a fixed appliance to avoid having their child lose the appliance if they believe that he/she will not be diligent in wearing it or storing it properly.

Useful advice if you wear a space maintainer

Care and cleaning

• For the lower fixed maintainer, thoroughly brush around the molar bands and the wire running on the tongue side of the teeth. Dental plaque accumulation on the appliance may lead to decalcification (stains) or caries on the teeth and generate bad breath, gum inflammation and irritation;
• The removable appliance must be removed and cleaned each time patients brush their teeth;
• A regular toothbrush and toothpaste can be used to vigorously clean the appliance;
• It is also important to clean the internal surface of the retainer (the one against the palate);
• Do not use very hot water to clean the appliance as this could distort the acrylic;
• You can soak your retainer in mouthwash (Scope, Listerine or other), a solution of water and vinegar or in Polident especially formulated to help remove dental plaque on orthodontic appliances;
• The appliance must always be worn or be kept in the protective case that was given to you. This will minimize the risks of losing or damaging the appliance;
• Past experience has shown us that the main reason an appliance is lost or broken is that it was not properly stored when not in use;
• Diet: it is important not to chew gum nor eat sticky or hard candies. They may loosen and even break the molar bands;
• If one of the bands of a fixed lower maintainer becomes mobile or loose, it is debonded and must be cemented again. If this happens, communicate with us as soon as possible so that we can fix the problem before caries develop under the band.
• The following reasons account for more than 80% of lost or broken removable appliances:
  • Not having stored the appliance in its protective case when not in the mouth;
  • Putting the appliance in your pockets and accidentally sitting on it!
  • At mealtime, wrapping the appliance in a napkin and mistakenly throwing it in the garbage at the end of the meal;
  • Not having kept the appliance out of the reach of young children and pets (dogs, cats…). Orthodontic appliances are not toys!
  • Having bitten on the appliance to insert it in the mouth (we will show you the proper way to gently insert a removable appliance);
  • Not having worn the appliance many consecutive days or weeks; this may allow the teeth to move and the removable appliance will not be well adapted to the teeth.

“Loose” appliance

• When a removable appliance is inserted into the mouth, it is quite “tight”. The anterior hooks and wire may be adjusted to apply a pressure that is more or less strong to hold the appliance on the teeth. Contact between the acrylic and the palatal mucus membrane contributes to the retention of the appliance in the mouth as well.
• With time, the hooks may become loose and make the space maintainer looser or mobile. Some people prefer an appliance that is very tight while other wish that it is barely held by the hooks and labial wire.
• Most importantly, the appliance must be worn regularly. The fact that it is loose or tight in the mouth does not change how efficient it is at all and this becomes more a question of taste or personal preference from patients.
• If the appliance is worn properly, it will play its role and will preserve the available space during tooth eruption.
• However, if the appliance is too loose and cannot hold in the mouth properly, it will not be efficient. Communicate with us in that case so we can fix the problem.

Repair and replacement of lost or broken appliances

• Minor repairs can usually be done in our in-house laboratory (repair fees may apply).
• If you notice that your appliance is damaged or doesn’t fit properly and cannot be worn as prescribed, contact us as soon as possible to schedule an appointment.
• If you lost your retainer or it is damaged beyond repair, it may have to be replaced by a new one if it is still indicated to wear one (a replacement fee will apply).
• Always bring your appliances to your appointments so that we can adjust them is necessary.

The “Bite Plane”: a space maintainer with a variation

Even if the main purpose of space maintainers is not to correct malocclusions, certain variations of these appliances may allow for some tooth movement and contribute to improving certain aspects of a malocclusion.This appliance, called a “bite plane”:

• Has an anterior ramp or biting plane preventing any contact between opposing teeth;
• Is used when there is excessive overbite (lower anterior teeth biting into the palate). See image on the opposite side;
• Wearing such an appliance for several months may allow to obtain vertical changes in the way the teeth close together by allowing the eruption of the posterior teeth. The anterior teeth of both arches will become separated from one another.

The appliance also:

• Acts as a regular space maintainer by preserving space and preventing tooth movements during eruption;
• Prevents the lower anterior teeth from biting into the palate and damaging the gingiva;
• Allows the posterior teeth to continue their normal eruption path and thus provide better support to the dentition.

➡ To learn more about this case.

Other information or use of a bite plane

• • • A bite plane can also be used during orthodontic corrections to help reduce the vertical overlap between opposing teeth and thus facilitate dental movements and bite opening.

Examples of eruption problems where space management was inadequate.

Headaches and migraines

• Even though this appliance is not made specifically to relieve headaches, using a bite plane in people having such symptoms and an important malocclusion where the overbite is excessive may sometimes relieve them to a certain degree or reduce the symptoms.
• We cannot “guarantee” or promise any improvement whatsoever, but it is possible to see, mostly in children, an important decrease in the frequency and severity of different symptoms when using a bite plane.
• The pictures below show a 9-year-old young girl (A) and an 8-year-old girl (B) having a very deep anterior bite and complaining about frequent headaches. The use of a bite plane to separate the upper teeth from the lower teeth reduced the symptoms significantly in the first case and completely in the second in only a few weeks. One year later, the symptoms are still absent. Please note that this does not mean that a bad bite or a malocclusion was the cause of headaches but we occasionally see children with deep bites complaining of headaches.
• We insist on the fact that we do not attempt to treat headaches and migraines using an orthodontic appliance, but we simply report that we have observed, in several occasions, the reduction of some symptoms when wearing such an appliance.
• The effect of such appliance may be similar to using an occlusal splint in cases presenting joint problems accompanied by various symptoms.