What is the purpose of adding material at the margins of a provisional crown?

The purpose of adding material at the margins of a provisional crown is to improve retention and sealing. The margins are critical areas where the provisional crown meets the tooth structure. By enhancing these margins, the provisional crown fits more securely, reducing the risk of dislodgement. This improved fit also helps to protect the underlying tooth from bacteria and debris, thereby minimizing the risk of secondary caries or contamination.

While aesthetics and color may be considerations in crown preparation, the primary functional goal of modifying the margins is to ensure that the provisional crown stays in place effectively during the interim period before a permanent restoration is completed. This focus on retention and sealing is crucial for both the patient's comfort and the integrity of the tooth.