National Dental Assisting Examining Board (NDAEB) Practice Exam

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Prepare for the National Dental Assisting Exam with comprehensive quiz questions, including multiple choice and detailed explanations. Equip yourself for success!

Each practice test/flash card set has 50 randomly selected questions from a bank of over 500. You'll get a new set of questions each time!

Practice this question and more.

How far below the gingival margin should a matrix band be seated?

0.5 mm
1 mm
1.5 mm
2 mm

The correct answer is: 1 mm

The correct distance for seating a matrix band is 1 mm below the gingival margin. This placement is critical to ensure that the band effectively forms a proper cavity restoration, enabling an adequate seal between the tooth structure and the restoration material. It helps in preventing excess material from flowing into the sulcus, which could lead to potential irritation or periodontal issues. Additionally, seating the band too shallow may not provide enough support for the filling material, which can lead to restoration failure. Conversely, going deeper than 1 mm could negatively impact the quality of the restoration, potentially harming the surrounding gingival tissue and complicating the finishing and contouring of the restoration. Therefore, a 1 mm placement strikes a balance between ensuring a stable foundation for the filling and preserving the health of the surrounding periodontal tissues.