What is causing a restricted opening if the dentist can't physically spread them open?

What is causing a restricted opening if the dentist can't physically spread them open?

• A. Anterior disc with reduction
• B. Anterior disc without reduction
• C. Muscle problems
• D. Dislocation

Answer: (B)

A restricted opening with an inability to spread the bite wide points to a mechanical block inside the joint, caused by anterior displacement of the articular disc that does not reduce during opening. When the disc sits in front of the condyle and doesn’t move back into place as the mouth opens, it interferes with the condyle’s forward translation and physically blocks full opening. This creates a “closed lock,” with a noticeably reduced interincisal opening. If the disc displaced anteriorly but does reduce during opening, you’d typically still be able to open more freely, often with a painful or clicking sensation but without a true lock. Muscle problems may cause pain and limit opening, but they don’t create a hard mechanical blockade. Dislocation tends to present with trouble closing the mouth or the jaw getting stuck in a position, not a pure inability to open widely. Therefore, the scenario described fits anterior disc displacement without reduction.

A restricted opening with an inability to spread the bite wide points to a mechanical block inside the joint, caused by anterior displacement of the articular disc that does not reduce during opening. When the disc sits in front of the condyle and doesn’t move back into place as the mouth opens, it interferes with the condyle’s forward translation and physically blocks full opening. This creates a “closed lock,” with a noticeably reduced interincisal opening.

If the disc displaced anteriorly but does reduce during opening, you’d typically still be able to open more freely, often with a painful or clicking sensation but without a true lock. Muscle problems may cause pain and limit opening, but they don’t create a hard mechanical blockade. Dislocation tends to present with trouble closing the mouth or the jaw getting stuck in a position, not a pure inability to open widely. Therefore, the scenario described fits anterior disc displacement without reduction.