Question: Is sub-gingival placement of crown margins really a clinically sound practice?
Is sub-gingival placement of crown margins really a clinically sound practice? Violating the biological width is surely bound to cause periodontal issues. Is not crown lengthening indicated or other periodontal treatment to avoid sub-gingival placement?
John Comisi: Such an interesting question! I agree we must respect the biologic space, but we have other factors that may come into play, such as esthetics, and the patients own ability to maintain the area. If, and this is always the “wild card”, if the patient can maintain the area, and the margins do not violate the space, then reliable success may be achieved.
Zohaib Akram: Impressive Dr Comisi.
John Comisi: Its just been my observation over the last 30+ years of private practice.
Umer Daood: depending on the probing depth of the gingival sulcus. A higher probing depth of more than 1.5 mm is a problem for ongoing gingival recession.
John Comisi: Yes Umer! Exactly!!
Zohaib Akram: Many thanks Dr John Comisi and Dr Umer Daood
Maxine Feinberg: Absolutely!
Maxine Feinberg: I just saw a patient recently with chronic inflammation on #8 due to this very issue. The tissue is hyperplastic and edematous.
Umer Daood: any bone loss Maxine Feinberg
Maxine Feinberg: Responsive to the encroachment of the biologic width.
Zohaib Akram: Hyperplastic and edematous tissue indicate acute signs. Not necessarily you will find alveolar bone loss. Yes, if these are secondary (overt) inflammation due to plaque on a previous chronic periodontal lesion, thats a separate thing.
Najiya Ilyas: What about the class 2 cases where mostly there is perio with bone loss ,should we be placing supra gingival margin over the restoration or sub gingival on tooth surface?
John Comisi: I would personally only finish to where the tooth needs coverage. Too much tooth reduction down the root surface will create a thinner prep and a weaker tooth. In fact there is a lot of discussion about the extent of coverage should not extend below a certain level not to violate the “enamel dome”. Graeme Milicich talks about this a lot. I like his concept.
Navin Boggavarapu: Maxine , spoken like a true periodontist. John, I totally agree. But no matter howMuch u explain patient wants esthetics over health.
John Comisi: Yes Navin, but patients do not dictate treatment. We must be sure to guide them to the correct direction, or it will come home to “bite us”.
Navin Boggavarapu: Very true. Hold ur ground. 😷
Nadia Naveed: Every effort should be made for supra gingival crown prep.Except for certain situations like esthetic considerations in ant teeth,short clinical crown and need for furrule effect etc…Further, Restoration placement after crown lengthening should be delayed for three to six months for better results in terms of e sthetics and to avoid gingival recession..
Rafay Khan: The issue comes while dealing with anterior crowns particularly in patients with thin gingival biotype.
Umer Daood: Well said Nadia Naveed
Zohaib Akram: Well put Nadia Naveed. Ferrule effect in the anterior teeth is a classical note which keeps the gingival curtain at place.
John Comisi: What a great thread!
Nadia Naveed: thanks for the appreciation..glad on being a part of this amazing group
Dennis Brown: This is an observation only. A well bonded composite that violates biologic space has no inflammation. Not true for a crown margin. Defies conventional wisdom. Will this hold true as the composite bond deteriorates, I do not know.
John Comisi: And with the Greater Curve Band capabilities (and that of the BioClear matrix system) to create direct restorations it could be possible.