What are Ankylosed Teeth?

by Dr. Joseph Thompson

Dental Ankylosis is an abnormal dental condition where there is a solid fixation of a tooth from a fusion of the root to the bone.  Normally, around the roots of our teeth, there is gum tissue that is called the periodontal ligament.  Inside the periodontal ligament are fibers that hold the tooth in the dental socket like a sling.  The bone and the root do not touch because the gum tissue is between them.

What are ankylosed teeth?

When ankylosis occurs, a bridge of material, either bone or root material, called cementum, builds between the root and the bone and connects the bone to the root.  When this occurs the tooth stops erupting and stays in the same place.  As the other teeth beside the ankylosed tooth erupt, they will tip due to the ankylosed tooth not moving.  If the ankylosed tooth is a primary tooth, it will displace the permanent tooth that is trying to erupt into its position.  Also, the ankylosis can cause reduction of the space needed for the permanent tooth to erupt causing an impaction.

Dental Ankylosis Tooth MovementA way to determine a tooth is ankylosed is by visual examination.  The ankylosed tooth will appear like it’s not erupting or it is sinking back into the gum tissue.  In some cases, the ankylosed tooth will completely disappear and be covered up with gum tissue.

Dental Ankylosis can occur with primary (baby) teeth and permanent (adult) teeth.  It is more common in primary teeth  than permanent teeth.

Ankylosed Upper Primary Second Molars

 Besides seeing a tooth that should be level with the adjacent teeth, another way of determining a tooth is ankylosed is by tapping on it.  Since the tooth is connected to the bone, it will create a lower frequency sound when tapped by the end of a metal mouth mirror.  The orthodontist or family dentist can compare the sounds of adjacent teeth with the suspected ankylosed tooth to determine a diagnosis.

Ankylosed Lower Second Primary Molar

 So Why is this Important?

Ankylosis of primary and permanent teeth can have an affect on the growth and development of the jaws and the developing occlusion.  Distortion of the alveolar jaw bone, space loss and distortion of jaw height are some conditions caused by dental ankylosis.  During the mixed dentition phase of a child, an orthodontist is watching the eruption of the teeth and is concerned about possible problems of eruption.  Some problems like ankylosis can be dealt with by diagnosing the ankylosed tooth early.  Early consultation with your orthodontist is necessary to monitor eruption of the teeth and should begin at the age of 5 or 6 years old.

Dental Xray Shows Four Ankylosed Primary Teeth

What Can Be Done about Dental Ankylosis?

In some cases, the damage has already been done by the ankylosed tooth and the orthodontist tries to let the permanent tooth erupt.  After a period of time, if the ankylosed tooth has not exfoliated, it will need to be removed.

In other cases, removal of the ankylosed tooth is necessary to prevent distorted jaw growth, adverse tooth eruption and space loss.  If the ankylosed tooth is a second primary molar tooth, a space maintainer is needed to keep the space from closing.  Ask your orthodontist about the possible need for a space maintainer after extraction of the ankylosed tooth.

It is suggested that a parent do a visual examination of their child’s teeth looking for teeth that are not level with the adjacent teeth.  If you see a tooth that looks submerged, or looks like a stair step from one tooth to the next, call your local orthodontist for a consultation.  You may be able to prevent some conditions that are harder to correct at a later date.

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