Which of the following uses for utility wax is correct?

Utility wax is primarily used in dental practices for modifying the shapes of impression trays and providing cushioning for braces. When working with impression trays, the wax can be used to adjust the fit, ensuring that it conforms to the patient's mouth more comfortably and accurately captures their dental impressions. Additionally, utility wax can be applied around orthodontic appliances to cushion against irritation and discomfort caused by braces.

The reasons behind the inaccuracy of the other choices relate to their specific functions and the materials used in dentistry. For instance, while certain waxes have specific adhesive or modifying properties, utility wax does not enhance the strength of dental materials, nor is it intended for use in cavity restoration or decay prevention. Filling cavities typically requires restorative materials like composite resins or amalgams, and preventive measures against tooth decay involve fluoride treatments or sealants rather than wax. Therefore, the primary role of utility wax is correctly identified in the choice concerning impression trays and braces.