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It is not uncommon to place a restoration on an upper second molar and have the contact open over time. The new crown is checked diligently at the seat appointment, and the contact flossed to ensure that it has the proper tension. The patient presents on an emergency because they are packing food, or at a routine hygiene exam and the open contact is detected. This can be frustrating and disconcerting for both the patient and the dentist. So why does this happen? As with many things in dentistry it is most likely multi-factorial, but one of the first things I check is the occlusion.
Often when this happens I find I have introduced a distalizing contact on the new crown or filling. Intercuspal position contacts that land on the mesial incline of a cusp will cause the tooth to be forced to the distal. If the contact is also slightly high and the tooth has no tooth holding it on the distal this can open the contact. In addition to MIP contacts Excursive interferences can create a distalizing force on the last tooth. For patients that parafunction this increased load and an excursive interference will compound each other. Another occlusal indication to look for is the first point of contact in centric relation, or what I refer to as a seated condylar position. Using a leaf gauge or bimanual guidance ( bilateral manipulation) check for the first point of contact. Often we have introduced a new FPC, and it can distalize the tooth.
In my office when I have found either of these occlusal issues on a tooth where a contact opened I simply adjust the occlusion and we wait and see what happens. Commonly, the contact will close again and the second molar will drift mesial into its original position. My guess is there are also other causes, and perio involvement is a complicating factor. However I have yet to see one of these happen in my patients where I could not identify an occlusal cause.
Good stuff! I’ve had this happen on occasion as well and never put 2 and 2 together. Thanks for the post!
Great post!
May i ask what is the correct management if this happens after 3months of cementation and and i did occlusal adjustment and waiting but contact still open ..
If you have checked all possible occlusal interferences, Centric Occlusion, excursives starting from Centric Occlusion, MIP, and excursives starting from MIP, see if the patient can retrude their mandible and check that. I use 2 thicknesses of 90 micron paper, so simulate what the patient can do at night under heavy parafunction.
If there is no possible occlusal contact, or I found one and removed it and gave the space 3-4 months to close and it hasn’t then I replace the crown. I linger in the new temp a long time to make sure a space doesn’t open again.
On occasion it can also be if the distal contact is to tight, it can push the distal tooth away opening the gap. Same goes for the last molar in arch if mesial contact is too tight. I’m considering it’s better to keep new crows light in occlusion as it will supper erupt into ideal shortly.
Thank you Dr 🌸🙏
I asked because i’ve seen some articles recommended proximal contact reshaping by flowable composite rather than remake the crown ..but i think it’s not practical enough to gain ideal contact and ensure longivity by this method