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Fast Facts - Dentogingival Unit

Fast Facts

Fast Facts - Perio Edition Episode 
[Andrew Johnston, RDH]
Welcome back,  everyone. You are listening to another episode of Fast Facts- Perio Edition brought to you by A Tale of Two Hygienists in partnership with DentistRX. And now, please welcome your host, Katrina Sanders.
[Katrina Sanders, RDH]
Today's episode continues the conversation around oral anatomy and today, I am thrilled to discuss the conversation around the dentogingival unit. Now, I know what you're thinking ...really Sanders? We're talking about the dentogingival unit? Yes, we are and let me tell you why. The dentogingival unit is a collective unit that refers to the epithelial attachment and the gingival connective tissue attachment to the cementum. Many of us know this to be termed the biologic width. And this is really important because biologic width we have continued to study with regards to its protective qualities, to the tooth structure and surrounding periodontium. Oftentimes during even an interview, you'll be asked to define for your doctor what a biologic width is, because your doctor wants you to understand that a biologic width is more than simply a free gingival groove or gingival fibers, but rather the biologic width determines the length coronal apical dimension of soft tissue attachments. Specifically, we are talking about the combination between the junctional epithelium and the gingival fibers leading to the alveolar bone.
The formation of this unit has important clinical applications, particularly during the periodontal evaluation and healing of gingiva after periodontal treatment. We know specifically that the biologic width needs to be respected with regards to restorative procedures.Schematically, we have identified that biologic width includes junctional epithelium, which research has determined to be about .97 millimeters, about one millimeter, and then the gingiva connective tissue attachment or those gingival fibres, which is about 1.07 millimeters.
This biologic width becomes important during prosthetic restorative treatment because we know that the margin of a restoration should not disturb the biologic width. Therefore, we know that the margin of a restoration should not be closer than 2 millimeters to the alveolar bone crest, because if it is, we consider this to be an invasion of the biologic width.
One other rapid hint that we can take a look at is evaluating the radiographs to determine the amount of space between the CEJ and the crest of bone. This, of course, we know comprises the dentogingival unit or the biologic width. One final note, in 2017 The American Academy of Periodontology changed their terminology. So now we have moved away from the term “biologic width” and we are now using the term “Supracrestal Attached Tissues”. How fancy!
Thank you for joining me today and join us next week for another scintillating conversation around oral anatomy.
This has been another episode of Fast Facts - Perio Edition with Katrina Sanders, RDH. Please feel free to reach me on Instagram @thedentalwinegenist or on my website Cheers.
[Andrew Johnston, RDH]
Thank you for listening to another episode of Fast Facts - Perio Edition, brought to you in part by DentistRX makers of the InteliSonic line of power brushes. Find out more by visiting their website at We'll see you next week for another Fast Fact!


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