Long term retention of sealants applied by inexperienced operators in Minneapolis.

A clinical trial of 4047 single applications of Nuva Seal placed on the occlusal surfaces of primary molars, permanent first and second molars and premolars by 250 dental students showed that the sealants were not well retained. The sealant was fully retained on 86% of all permanent posterior teeth at 3 months, on 76% at 6 months, 58% at 12 months, 52% at 24 months and 41% at 36 months. At 4 years, complete sealant coverage was shown by 14% of primary molars, 25% of permanent molars and 68% of premolars. Permanent mandibular molars and premolars were superior to permanent maxillary molars and premolars in fully retaining sealants. Following sealant failure, i.e. providing partial coverage or missing, permanent maxillary molars and premolars were more prone to occlusal caries than permanent mandibular molars and premolars. At 4 years, caries was diagnosed in 40% of applications to permanent molars and in 9% of applications to premolars. Twelve instances of caries under apparently intact sealants were seen.