Background: Occlusal caries is the main reason for restorative therapy in the young permanent dentition, but restorations have limited survival time and may also weaken the tooth. An intact fissure sealing is an effective preventive treatment of occlusal caries lesions and may be used therapeutically to arrest the caries progression. However, the major challenge with fissure sealants is the frequent need for re-treatments, mostly due to inadequate retention.

Purpose: To quantify the longevity and effectiveness of the 6 resin sealants used prophylactically and therapeutically in permanent molar teeth.

Study design: The study is carried out as a prospective, clinically controlled study with split-mouth design, where each of the 60 dentists/dental hygienists from 13 municipalities in Denmark uses 2 of the 6 sealants. The treatments are examined clinically and radiologically after 1, 2, 3, and 5 years.

The choice of the two materials is randomized and carried out so that all materials are used equally frequent and with an even distribution between dentists and dental hygienists.

Inclusion Criteria:

• Children and adolescents 5-14 years of age
• Children with 2, 4, 6 or 8 molars assessed to be in need of prophylactic or therapeutic sealing
• The radiographic penetration of the occlusal caries lesion must be limited halfway through the dentin

Exclusion Criteria:

• In case the occlusal surface is restored with communication between the restoration and the included lesion
• Subjects with chronic diseases that could affect their caries pattern
• Pain in teeth