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Eruption trouble with the 6 year upper molar

Dr. Michel Champagne, BA, DMD, MAGD, IBO, CDE  

If you have never encountered in a regular exam an eruption problem with the upper first molar locked in behind the primary secondary molar, please raise your hand.

We are then always faced with the same question ”what are my options?”. These options may vary depending of the detailed clinical picture. I will not expose an exhaustive list but just take a look at the more frequent options:

  1. Situation A : the primary molar somewhat resorbed and mobile. The solution is easy and will consist of the extraction of the primary molar to facilitate the natural eruption of the permanent molar, a reevaluation of the position of tooth  #6 once erupted  and looking at removable or fixed mechanics to replace the molar in its proper position to allow the eruption of the second bicuspid. Often a space maintainer will have to be put in to preserve the gained space.
  2. Situation B : the primary molar is non mobile presenting minor resorption. Here we have to remember and apply the  KISS principle (Keep It Simple Stupid). The first factor to look at is the possibility of inserting an explorer tip under the contact point from buccal. This opens up the possibility of inserting a separation device between the two teeth with a high probability of success.

Today we will focus our attention on situation A. The most important factor here is cooperation since the simplest approach is a removable appliance. This approach is mostly intended  for the 6-8 age group and in most of the cases there is good cooperation at that age. In such a situation, we have to extract tooth #E, wait a few months for the sufficient eruption of #6.  Most of the crown should be erupted to be able to retain a distalising spring. If minimal eruption is encountered, it is possible to do a composite add-o to the occlusal surface giving a stop to oppose the spring. In some designs, a screw can replace the finger spring. This approach is simple and can be used by a dentist with minimal orthodontic knowledge. The success relies on cooperation in appliance wear, disarticulation of the occlusion if needed to avoid distalisation interferences and good chair side instructions to assure parents and patient cooperation and knowledge in the manipulation of the appliance for proper activation of the screw or spring.

In the next blog we will discuss fixed techniques to solve the impaction of the upper first molar.