Which of the following is a characteristic of an ideal sealant material?

An ideal sealant material should have good retention and resistance to wear because these characteristics ensure that the sealant effectively protects the tooth from decay over a long period. Good retention implies that the sealant adheres well to the tooth surface, preventing moisture and bacteria from entering pits and fissures, which are common sites for caries development. Resistance to wear is also crucial, as sealants need to withstand the forces of chewing and other oral functions without degrading or losing their protective qualities.

In contrast, while fluorescence under UV light can be a desirable property for identifying the presence of a sealant, it does not directly impact its effectiveness in sealing teeth. Low wear resistance would be undesirable as it could lead to the sealant wearing down quickly, reducing its effectiveness. High viscosity might make the material difficult to place accurately in the tooth's fissures and pits, impacting the sealant's ability to adhere and cover properly. Thus, good retention and resistance to wear are key characteristics for an effective sealant.