Potential for Root Resorption of a Permanent Maxillary Incisor

Even though this is not a common problem you need to be informed that it is always a possibility. One of the most frequent causes of this is when the unerupted permanent Canine literally sits on top of the root of the permanent lateral incisor.

Most of the time the canine will move off of the lateral incisor root without any damage to that tooth. In a very small percentage of cases the lateral incisor root will resorb (melt away) just as the root of a baby tooth will be lost. Even though this occurs in a very small percentage of cases, it can occur and very little can be done about it.

In most cases this occurs because the developing tooth bud of the permanent canine forms too far towards the middle of the patient’s dental arch rather than at the corner of the mouth. This happens more frequently in small and narrow upper dental arches. Depending on the rest of the patient’s dental and skeletal relationships there are a few things that can be done to decrease the odds of losing an anterior tooth:

• Widen the upper arch with an expander, creating more room for anterior teeth.
• Surgically expose the permanent canine and attempt to move it off of the root of the lateral incisor if the timing is correct.
• In some cases extracting the first bicuspids may be indicated for severe crowding and this may lesson the odds of the canine causing problems with the lateral incisor. If there is not severe crowding this is not always a good option because it may have a negative affect on the patient’s facial features and does not insure that there will be no damage to the lateral incisor.
• Sometimes we just have to wait and see what develops because none of the treatment options are appropriate at the time.

All treatment options will be discussed. The pros and cons of each option will also be discussed. Again, regardless of treatment, there may be a loss of the root and therefore loss of the permanent lateral incisor and in severe cases even the central incisor.

The incidence of loss of one or more anterior permanent teeth from the ectopic eruption of canines is 1.7% to 2.2% or approximately 1 in 50. (Ericson and Kurol-Community Dentistry and Epidemilogy- 1986-Sweden) 12.5% of impacted canines result in resorption of roots of anterior teeth and 81% of these are lateral incisors. (Thylander and Myberg-1973-Scand J. Dent. Res.) 0.71% of all children in the 10-13 year age group, permanent incisors have resorbed because of the ectopic eruption of canines. (Ericson and Kurol-1987-AJO) You can see why we are concerned about possible damage to the lateral and central incisors from the poor eruption path of the canines. No matter what treatment path is taken their will still be a risk to the roots of the anterior teeth. We can reduce the risk factors, but we cannot take that risk factors to zero.

The following radiographs are examples of root resoption caused by the poor eruption path of maxillary canines as reported by Ericson and Kurol, Angle Orthodontist, Vol 70, No. 4, 2000.