I want to share with you today my thoughts and considerations for treating the maxillary peg lateral incisor. While at first glance, the maxillary peg lateral restoration may seem to be pretty straight forward, there are several factors to consider when evaluating these patients for cosmetic dental treatment.
Commonly, other teeth in the maxillary arch are smaller than normal. Research by Jane Wright for her master thesis at Marquette University School of Dentistry, found that the teeth in the maxillary arch can be significantly narrower than average, from 2nd bicuspid to 2nd bicuspid.
Unfortunately, it has been my experience for orthodontists to ignore the issue that many other teeth are narrower than average, and close all spaces, leaving a very large diastema between the canine and the peg lateral. This will most often create a non-restorable clinical situation for the restorative dentists.
I have also found that it is not uncommon for one or more maxillary teeth to have atypical form in the peg lateral patient. I see this with cuspids especially, but also with the central incisors. It is not unusual that the central incisors are not symmetrical in these peg lateral cases. These aberrant tooth forms will dictate that other teeth, beyond the peg lateral incisors, may need to be treated to create naturally appearing restorations.
Finally, and I think a very big issue, I frequently see that there is altered passive eruption, or incomplete gingival tissue migration related to the maxillary dentition, in these peg lateral patients. These patients will often present with short clinical crowns and a gummy smile.
Based on research by Dr. Bill Robbins, we should anticipate that the free gingival margins of the maxillary teeth should be close to the CEJ’s, when the adolescent is around 16 years old.
To differentiate between just a short clinical crown, and to evaluate if there is altered passive eruption, I use an explorer and run the tip under the free gingival margin into the sulcus. I feel for the transition between the smooth enamel surface, and the more ‘pebbly’ feel of the root surface. If, while moving the explorer under the surface, I only feel smooth enamel, likely, the soft tissue has not migrated apically, exposing the full clinical crown of the tooth.
For reference, the average unworn maxillary central incisor is between 10.5-11.5 mm long (based on research by Belser, Magne and others). A normal lateral incisor should be about 9.5 mm, and a canine should measure similar to the maxillary central incisor. In many situations, esthetic crown lengthening is necessary before the cosmetic treatment, to create naturally appearing restorations.
In conclusion, regardless of the restorative material that you will be using to restore the peg lateral incisor, evaluate the other teeth in the arch for tooth size and form to determine if other teeth need cosmetic restorative treatment to create normal tooth form. Additionally, consider if the tissue height is appropriate and if crown lengthening procedures should be recommended before restoring the case.
Yours for better dentistry,
