Question

"Patient: Female, 38-years-old.

Chief complaint: ""I was chewing and part of my tooth broke.""
Background/or patient history: Your patient is a regular attender, maintains good oral hygiene, and has a low caries risk. There are no relevant medical factors. She has a large mesio-occlusal (MO) composite restoration in tooth #3. This was placed by a previous dentist at least eight-years ago.
Current Findings: Apart from a sharp edge which is uncomfortable on her cheek, the patient has no symptoms. On examination, you find the mesiobuccal cuspof tooth #3 has fractured off supragingival. The tooth is vital and there is no evidence of caries. The occlusion is class I. After a discussion, you and your patient elect to restore tooth #3 today with a direct composite resin restoration, on the understanding that she will return in the coming months to restore the tooth definitively with a more durable ceramic restoration.

Think about the correct placement of the fractured cusp in your restoration:
a. Its cusp tip is not in contact during centric occlusion because it is a supporting cusp
b. Its cusp tip is not in contact during centric occlusion because it is a guiding cusp
c. Its cusp tip is in contact during centric occlusion because it is a supporting cusp
d. Its cusp tip is in contact during centric occlusion because it is a guiding cusp"

Answer 1

The fractured cusp in tooth #3 is a guiding cusp and its cusp tip is not in contact during centric occlusion.

Step-by-step explanation:

Based on the information provided, the fractured cusp of the mesiobuccal cusp in tooth #3 is a guiding cusp and its cusp tip is not in contact during centric occlusion. A supporting cusp would be in contact during centric occlusion. Since the patient has a large mesio-occlusal (MO) composite restoration in tooth #3, the fractured cusp does not play a major role in the occlusion. Therefore, it is not necessary to include it in the restoration.