Hypodontia clinic

Hypodontia is a condition in which one or more teeth fail to develop. Hypodontia principally affects the adult (permanent) teeth and is seen in about 5% of the population. Very occasionally no teeth develop, a condition called anodontia. Hypodontia is more common in females than males with a ratio of 3:2 and appears to affect all racial groups.

Apart from missing teeth, there are other changes which can occur in the mouth, including:

Microdontia

This is a condition in which the teeth are smaller than normal, which can produce a less acceptable appearance, particularly as this often results in gaps between the teeth and makes the effects of the missing teeth appear more evident.

Conical teeth

Sometimes people with hypodontia have teeth which are very tapered, rather than having a more typical square or rounded shape.

Retained primary (baby) teeth

Where the adult teeth have not developed, it is very common for the baby teeth to remain in place well into adulthood. However, it is difficult to predict how long an individual tooth will remain. When the primary teeth are retained then they may become severely worn, often down to the level of the gums. Sometimes these teeth have to be removed because they interfere with the normal development of nearby permanent teeth or become painful or loose.

Reduced jaw growth

The bones of the jaws grow to support the adult teeth, and when these are missing the bone can fail to develop fully. As a result, the appearance may be less satisfactory, and problems can be encountered when trying to place implants, as there may be insufficient bone to insert them.

Hypodontia is usually genetically linked, however people with the condition do not always have children who are similarly affected. In the same way, hypodontia can also apparently arise spontaneously. When one child is affected, it is not always the case that their brothers and/or sisters will also have hypodontia, or that the pattern of missing teeth will be the same in all members of the family.

Hypodontia is found in association with many genetic disorders, of which the ectodermal dysplasias (EDs) are the most common. This is a large group of conditions in which the tissues which grow from the outer layer of the embryo do not develop normally. They include the hair, sweat glands, nails, and teeth. The severity of these conditions will vary from person to person.

Paediatric dentistry is the oral and dental care of children and adolescents, under the age of 16 years. It is age specific and considers the needs of the patient in a holistic manner. The provision of treatment uses different types of behaviour management, appropriate for the patient and the procedure to be carried out. It covers prevention, restorative treatment, and surgery.

“Shared care” with other practitioners

The majority of patients will be under the care of a general dental practitioner or a community dental officer for regular check-ups and routine treatment. It is expected that this would continue throughout the specialised treatment carried out through the Hypodontia Clinic.

Prevention

Preventing dental disease is a key component of modern dentistry. Good oral hygiene and decay free teeth are essential to protect the remaining teeth present and prior to the start of a complex treatment plan. The oral health should be maintained by a good preventive programme, including an effective cleaning technique, a safe diet with limited sugar and acid intake, and additional techniques such as fissure sealants.

If the oral health is not stabilised the start of orthodontic (brace) treatment, or the provision of restorative care may jeopardise the situation and compromise future treatment.

Restorative care

The teeth present may be unsightly because of their small size and pointed shape. Early in the treatment plan simply reshaping the teeth with a tooth-coloured material (composite) which is stuck onto the teeth can give a marked aesthetic improvement. The technique is non-invasive and can be a good introduction to dental treatment, with visible benefits as well. Replacing missing teeth in young patients is achieved, whenever possible, with adhesive bridges which are glued to the tooth enamel with a special material. The metal framework covers the teeth adjacent to the gap, with little to no tooth preparation necessary.

When many teeth are missing, dentures may be considered. There are several different types, and some may give a marked facial improvement, by building up the height of the jaws and filling out the lips and cheeks. These dentures will require remaking quite frequently, depending on the rate of growth.

Other restorations like onlays may also be provided to help prolong the longevity of deciduous teeth where their permanent successors are missing.

Surgery

The extraction of decayed teeth or those with a poor prognosis because of a lack of root may be required. Baby teeth without permanent successors may appear to be sinking into the gum, and these teeth sometimes also require removal.

Adult teeth can remain under the gum instead of erupting into their normal positions. If there are signs the adult teeth are not going to erupt by themselves, or if they start to develop in the incorrect position, then a small surgical procedure can be performed to uncover these teeth and allow the orthodontist to move them into their correct position.

Another surgical procedure that is sometimes required is the removal of the fleshy piece of gum under the lip between the front teeth. If this fleshy gum (called a fraenum) is large it can contribute to a gap forming between the two front teeth and its removal is needed as part of an overall treatment plan to improve the look of the smile.

Orthodontics is a specialist branch of dentistry concerned with the management of abnormalities in the development of the jaws and teeth.

Orthodontic treatment most commonly involves the use of fixed braces although some patients can benefit from the use of removable braces or occasionally just correctly timed extractions alone.

Why might I need Orthodontic treatment?

There are numerous reasons why patients can benefit from orthodontic treatment. In patients who have hypodontia the teeth that are present usually drift into the space of the missing tooth/teeth leaving unevenly sized gaps. These gaps are usually either too small or too large to fit an ideal sized tooth. Hence, orthodontic treatment can benefit patients by moving their teeth to the correct locations and therefore creating the ideal amount of space for the most cosmetic tooth replacement. Sometimes, it may be possible to close the spaces where teeth are missing and eliminate the need for a replacement tooth.

How early can treatment start?

Orthodontic treatment can occasionally start below the age of ten years to correct localised problems with dental development and is then often given the name ‘interceptive treatment’. The aim of interceptive treatment is to prevent more complicated problems from developing later by using a simple treatment approach at an earlier stage. Normally though, orthodontic treatment is undertaken in patients when the majority of adult teeth have erupted. This is after the ages of 12-14 years.

How long does treatment take and what is the interval between appointments?

On average, fixed brace treatment takes approximately 2 years to complete although this depends on the complexity of your case. Treatment time can also be significantly increased by missed appointments and breakages of the brace. Normally, appointments are scheduled at 6-8 weekly intervals. If breakages occur, there may be a necessity to attend between appointments.

Who will carry out my treatment?

Within a teaching institution, treatment is usually undertaken by specialist trainees/postgraduate students under the supervision of a senior member of staff. All clinicians are qualified dentists and have experience in treating patients with dental problems.

Will I still need to see my regular dentist?

Yes. Regular dental check-ups are important to help pick up early signs of tooth decay and gum disease. It is also important to stay registered with your dentist, by attending regularly, as he or she may need to carry out tooth replacement treatment following orthodontics.

If spaces are being re-opened for the replacement of missing teeth, does this mean I will have to live with large spaces during Orthodontic treatment?

No. Once spaces of the correct size have been created, it is usually possible to place an artificial tooth attached onto the brace to prevent unsightly gaps. However, there may be a short period when there may be small spaces present. Care does have to be taken with these temporary tooth replacements as they can be prone to breakage if hard foods are eaten.

What happens when the brace is removed?

Following removal of your fixed brace, you will be fitted with retainers. Retainers are often plastic removable braces that help to maintain the teeth in the corrected position. If there are gaps for missing teeth, artificial teeth can often be placed onto the retainer to help maintain dental appearance and maintain the spaces created during orthodontic treatment.

Failure to wear retainers as instructed can lead to tooth movement and reversal of the positive changes achieved during orthodontics. You would not be offered re-treatment to correct this adverse tooth movement.

How long will I have to wear my retainers?

Retainers should be worn all the time following orthodontic treatment, if tooth replacement is to be considered. This is important as any spaces that have been created or redistributed can easily change in size. Once tooth replacement has taken place, it is possible to switch to nights-only retainer wear.

After a year it will be possible to gradually reduce the number of nights a retainer is worn until only a few nights a week are required. The only way to guarantee that your teeth remain straight is to wear retainers indefinitely. Once orthodontic treatment is complete, patients are expected to maintain their retainers with their dentist or a local orthodontic specialist.

Restorative dentistry is a specialist branch of dentistry concerned with the reconstruction of the teeth and mouth to improve the chewing, cosmetic and psychological requirements of the individual patient.

Why might I need restorative treatment?

There are a variety of reasons why patients with hypodontia can benefit from restorative treatment. The teeth that are present are often small or incorrectly shaped. Building these teeth up can significantly improve the overall appearance of the smile. Sometimes this is the only treatment that is required.

More often however, the gaps resulting from the missing teeth allow the adjacent teeth to drift into this space and orthodontic treatment with braces is needed to move teeth into their correct positions. Restorative techniques are then used to replace the missing teeth in the most suitable way.

How can teeth be replaced?

Missing teeth do not always need to be replaced. The absent tooth may be sufficiently far back in the mouth not to be noticeable. Sometimes, orthodontic treatment alone can close all the gaps without the need for further restorative care.

On other occasions there are gaps in the mouth that need to be restored. A variety of methods are available for this:

• Bridgework. Bridges are artificial teeth that are glued onto one or more of the adjacent (anchor) teeth. Therefore, they are termed a ‘fixed’ option as it is not intended for the patient to be able to take the bridgework out of the mouth. Bridges can be ‘conventional’ or ‘adhesive’. Conventional bridges involve trimming down the tooth or teeth adjacent to the gap to allow the bridge with the false tooth to be glued over the re-shaped tooth/teeth. These bridges involve the removal of significant amounts of the crown of a tooth but are useful in situations where the anchor teeth already have large fillings. Adhesive bridges require very little, if any, tooth preparation and rely mainly on a special cement to bond the bridge to the neighbouring teeth. Adhesive bridges are often the preferred choice.
• Dentures. A denture is a removable replacement for missing teeth and adjacent tissues such as the gums. It is made of acrylic resin, sometimes in combination with various metals. A complete denture replaces all the teeth, while a partial denture fills in the spaces created by some missing teeth and prevents other teeth from changing position. In some instances, it may be beneficial to leave the root part of a tooth, or a baby tooth, in place and make the denture to fit over these teeth. This type of denture is called an overdenture and enables the missing teeth to be relatively quickly replaced while at the same time keeping the jaw bone around the retained teeth. Maintaining the level of the jaw bone may allow future replacement of the teeth with implants.
• Implants. A dental implant is a screw-shaped device, usually made of titanium, that is inserted into the jawbone to take the place of a missing tooth root. Once the implant has become firmly attached to the jaw bone (called osseointegration) a replacement tooth is connected to the top of the implant. A single implant can be used to replace one tooth or multiple implants can be utilised for a bridge. Alternatively, several implants may be employed to stabilise a denture. Dental implants offer a number of advantages such as; allowing you to have a replacement tooth that feels like your own, removing the need to drill adjacent teeth for bridgework, and preserving the jawbone. Sufficient bone needs to be present to house the implant and special x-rays or a CT scan are used to determine the bone volume.

What if I do not have enough bone for implants?

If there is not enough bone in the positions where implants are to be placed, it is possible to augment the area with grafts. There are many types of grafts and the technique used will depend on how much of a bone deficiency there is. If only a small bony defect exists, synthetic or other bone-stimulating materials may be used. These provide a scaffolding to allow your own bone to grow into the area, with the material eventually being replaced by bone. The materials are usually placed at the same time as the implant surgery.

Should the amount of bone required be moderately large, bone from another part of the jaw can be used and grafted into the defect. This is usually performed as a separate procedure, with the bone being built up first and allowed to integrate for several months before the implants are inserted. When large quantities of bone are required, sites outside of the mouth, for example the hip, are used to obtain the bone.

Bone grafting from inside or outside of the mouth does extend the overall treatment time by approximately 3-6 months.

I have been told I do not have very thick gums. How will this affect treatment?

Gums provide an important covering for the jaw bones. Some people have a thick robust layer of gum tissue whereas others have rather thin delicate gums. Thin gums are prone to shrinkage, especially around implants and this may compromise the appearance of the artificial tooth. In addition where a tooth has not developed, or has been removed, the bone and the gums may be curved inwards creating a depression between the adjacent teeth.

The false tooth will then not have a natural appearance and will seem to sit on top of the gums instead of appearing to emerge nicely out of the gum layer. These problems can be overcome by augmenting the gums and can be timed so that they do not significantly increase the overall treatment time.

How can teeth be built up?

Often, a person with hypodontia also has small or wrongly shaped teeth that would benefit from being re-shaped. Occasionally it is possible to correct the tooth shape by careful grinding of the enamel, but frequently it is also necessary to add composite material or place a veneer on the tooth.

• Composite. Dental composite is a white filling material that can be placed directly on to the tooth surface and sculptured to correct the shape. The composite bonds to the tooth surface and is a conservative method of greatly enhancing the appearance of the teeth. Very little, if any, of the tooth surface needs to be removed with a drill. Dental composite is available in a variety of colours to blend in with the natural tooth colour and provide a natural appearance. It is relatively easy to repair or re-polish the composite as necessary.
• Veneer. Veneers are wafer thin facings, usually made from porcelain, that are glued onto the front surface of a tooth, much like a false fingernail fits over a nail. The facing can be made of the correct shape for the particular tooth and of the desired colour. Veneers are useful when composite fillings have already failed or where the natural tooth colour needs to be significantly changed. Approximately 0.5-0.75mm thickness of tooth structure is removed from the outer surface to provide sufficient space for the veneer. Commonly, the veneer is sent to a dental laboratory to be constructed and therefore the prepared tooth is temporarily built up until the veneer can be fitted.

Almost all forms of dental treatment require a certain degree of maintenance and review. The more complex the treatment, the more maintenance required. At the Eastman Dental Hospital, we work in partnership with your dentist. Sometimes, a treatment plan is formulated on the hypodontia clinic and sent to your dentist to carry out.

In other instances, we will perform some or all of the treatment, but it is important you continue to see your dental practitioner on a regular basis to maintain the mouth in a healthy condition.

What is expected of me before and during my restorative treatment?

Often the management of hypodontia involves treatment over an extended period of time. The treatment can be complex with several specialists working as a team to produce the desired result, this results in a lot of time and effort and financial cost to the NHS. Although treatment can be demanding both for the patient and the clinician, it is also extremely rewarding when everything progresses well.

It is of the utmost importance that patients who receive such complex treatment are well-motivated, display a good level of oral hygiene and are able appreciate the need to maintain the mouth in a healthy state before treatment commences. During treatment, a sequence of appointments is often scheduled which should be adhered to wherever possible. Repeated cancellation of appointments can significantly increase the time taken to complete the work.

Careful follow up of the treatment is necessary to ensure any problems are detected early and treated appropriately. This is why regular visits to your dentist are so important.

Often you will have been seen in the paediatric, orthodontic or restorative department for a preliminary assessment. You will then be seen on the Hypodontia clinic and initially, you will be asked several questions including your main dental concerns, and relevant medical history. A dental examination will then be undertaken, and a decision will be made if any x-rays are required to supplement the clinical findings. If your dentist has recently taken x-ray pictures, it is worthwhile asking if you can bring these along to the appointment.

Once a full examination has been undertaken, your treatment options will be explained. Occasionally, additional special records (for example, dental study models) are required before treatment options can be given, and you may be asked to attend a separate appointment to have these performed.

Following the consultation, a letter will be written to your dentist, and copied to you, that outlines the main clinical findings, treatment options and the outcome of the visit. This letter can take a few weeks to reach the dentist.

Some patients will not be at the correct dental developmental stage to start treatment and they may need to be seen again on the Hypodontia clinic after this initial visit. Other patients will be ready and will be placed onto the appropriate orthodontic, paediatric, or restorative waiting list.

If your treatment involves less complex procedures, these will be referred to your own dentist or local specialist orthodontist who referred you, to manage.