HOSA Dental Terminology Practice

What is the primary purpose of an onlay?

1. To replace all of the tooth structure

2. To cover some of the tooth's occlusal surfaces

3. To act as a bridge

4. To provide aesthetic appeal

The correct answer is: To cover some of the tooth's occlusal surfaces

An onlay is a type of dental restoration that is designed specifically to cover and protect some of the occlusal (chewing) surfaces of a tooth, particularly when there is damage or decay that does not warrant a full crown. The primary function of an onlay is to restore strength and integrity to the tooth while preserving as much of the natural tooth structure as possible. By adhering to the occlusal and possibly some of the proximal surfaces, an onlay provides support for normal chewing function and prevents further damage to the tooth. The focus of an onlay is not to replace all of the tooth structure, which would be more characteristic of a full crown. An onlay is also not intended to serve as a bridge; a dental bridge is specifically designed to replace missing teeth by anchoring to adjacent teeth. Finally, while an onlay can contribute to aesthetic appeal, its primary purpose is functional, ensuring that the tooth can withstand the forces of chewing while maintaining as much of its natural form and function as possible.