Gingiva & the Supracrestal Attachment

Gingival epithelia

Epithelium	Keratinized?	Key facts
Oral (outer) gingival epithelium	Yes (ortho- or parakeratinized)	Faces the mouth; rete ridges; stippling in many healthy patients
Sulcular epithelium	No	Lines the sulcus; semipermeable
Junctional epithelium	No	Attaches to the tooth with an internal basal lamina and hemidesmosomes; very fast turnover; permeable, so it is the first site of inflammatory change

Free gingiva: from the gingival margin to the free gingival groove, surrounding the sulcus (healthy clinical probing depth about 1–3 mm).
Attached gingiva: from the free gingival groove to the mucogingival junction, bound to bone; its width varies by site (usually widest in the maxillary incisor area and narrowest around the mandibular canines and premolars).
Attached gingiva width = keratinized tissue width − probing depth.
Alveolar mucosa below the mucogingival junction is nonkeratinized, movable and redder.
The col is a nonkeratinized dip in the interdental papilla under the contact of posterior teeth, a weak spot for plaque-induced inflammation.

Component	Classic average (Gargiulo cadaver data)
Sulcus depth (histologic)	About 0.7 mm (not part of the attachment)
Junctional epithelium	About 1 mm
Connective tissue attachment	About 1 mm
Total attachment (JE + CT)	About 2 mm

Placing a restoration margin into this zone tends to cause chronic inflammation, recession or bone loss; crown lengthening restores room (often planned as about 3 mm from margin to bone).
The 2017 World Workshop replaced 'biologic width' with 'supracrestal tissue attachment' and 'biotype' with 'periodontal phenotype' (thin or thick).

Dentogingival (most numerous), alveologingival, circular, dentoperiosteal and transseptal fibers hold the gingiva to the tooth and bone.
Transseptal fibers connect adjacent teeth over the alveolar crest and contribute to orthodontic relapse.

Calling the junctional epithelium keratinized.
Using 'biologic width' and 'biotype' as the current 2017 terms.
Measuring attached gingiva as the whole keratinized band: subtract the probing depth.
Treating the sulcus depth as part of the supracrestal attachment.

Pick an answer to see right away whether it is correct and why.

A patient has 5 mm of keratinized gingiva on the facial of #8 and a 2 mm probing depth. What is the width of the attached gingiva?
Which epithelium attaches the gingiva to the tooth surface?
The supracrestal tissue attachment is made of:
Why is the interdental col vulnerable to inflammation?
A crown margin placed 0.5 mm from the alveolar crest is likely to cause:

0 of 5 answered

Answer key: 1 C · 2 D · 3 C · 4 B · 5 A