Bottom Line:
Dental caries in the primary molars is highly predictive of the occurrence of dental caries in the permanent dentition

By Vincent G. Kokich, DDS, MSD

Based on: Li Y, Wang W: Predicting Caries in Permanent Teeth From Caries in Primary Teeth: An Eight-Year Cohort Study. J Dent Res 2002; 81 (August): 561-566

Is it possible to predict caries in the permanent teeth by evaluating the incidence of caries in their primary dentitions? This study can give us some hints on which patients could be potential problem patients with caries during orthodontic therapy. The purpose of this study was to evaluate a group of children long term to determine if caries of the primary dentition was predictive of caries in the permanent dentition. In order to accomplish this task, these authors evaluated over 500 children back in 1992. At that time, these children were between 3 and 4 years of age. Each child had an intraoral exam to determine the presence of occlusal caries in the primary dentition. This same group of children was recalled and evaluated 8 years later in the year 2000. At that point in time, 350 of the original sample could be located and reevaluated. The same evaluation process was performed, but these children were now between 11 and 13 years of age. The caries evaluation was made of any of the permanent teeth that were erupted. The authors then compared the amount of decay in the primary dentition and that in the permanent dentition in each individual longitudinally.

The big question is can you predict caries in the permanent dentition if you see it in the primary dentition? The answer – yes.

The teeth you want to look at are the primary molars.

• If a child develops dental caries in the permanent teeth, 95% of them had caries in their primary teeth.
• Furthermore, if children did not have caries in their primary teeth, 85% remained caries free by the age of 12.
• If a child has caries in the primary teeth, they are 3 times more likely to develop caries in the permanent teeth compared to children who have no caries and the best predictor is caries in the primary molars.
• If your patient has caries in the primary molars and the maxillary or mandibular arch, there is an 85% predictive value for caries in the permanent dentition.

This study suggests orthodontists should be more observant of dental decay. If you see decay or restorations of the primary molars, it should be charted. It could give an indication of whether the child could be a higher caries risk patient in the permanent dentition when orthodontic treatment is underway.