Help with periodontal surgery question

[dentalstudent021]

Hello,

I’m in third year of dental school and am reviewing the different mucogingival surgery techniques for recession defects. Can anyone explain the difference between a CT graft and subepithelial CT graft?

I can’t seem to find reliable sources explaining the indications for each and their differences.

Thank you for your input and ideas!

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[DrDentMP]

Hello dentalstudent02,

CT graft is a broad term- Subepithelial CT Graft (SCTG) is a type of CT graft.

-As the name suggests, sub means below- CT below epithelium (lamina propria) is used-

• SCTG is harvested from a donor site using Split-Thickness Flap.
• The "leftover" epithelium retains the natural superficial architecture of mucosa and,
• this creates closed wounds (which heals by primary intention) at donor and recipient sites.
• You could avoid cutting periosteum at the donor site which results in significantly less pain and discomfort.
• You get better blood supply - coming from periosteum and flap.
• Lamina propria from the donor site adapts very well at the recipient site - you get good "pink color", more esthetic.

-Historically (not as common now but is still done sometimes in less esthetic regions), CT grafting utilized Free Gingival Grafts (lamina propria with epithelium)-

• FGG is harvested using Full-thickness Flap.
• FGG results in "entire tissue lost at donor site- from epithelium to periosteum" and,
• this creates open wounds (which heals by secondary intention)
• The periosteum is compromised = blood supply is compromised, more discomfort.
• Color, texture after healing may not be ideal- may result in "keloid" like scarring at recipient site (that grows over adjacent gingival tissue).
• For ease of understanding, FGG = "Difficult Healing" compared from SCTG = "Easy healing"

I hope it helps.

DrDentMP

 

[dentalstudent021]

Hi DrDentMP, thank you so much for taking the time to answer my question!

You mentioned that for FGG, we are using the lamina propria and epithelium of the palate, but also indicated that a full thickness mucoperiosteal flap is needed at the donor site. I am wondering that since we are only using the superficial epithelium layer for the FGG, why we need a full thickness flap to be raised at the donor site?
At the recipient site, would the site need to be prepared so that the epithelium is removed, leaving the underlying connective tissue? Or is it prepared differently?

Also, for the subepithelial CT graft, an online resource suggested that at the recipient site, the connective tissue graft may be left exposed without it being covered by epithelium, since there is a root defect at the recipient site and would not have any epithelium present in that area in the first place. Is this correct? Or does the CT graft need to be covered by epithelium at the recipient site (by a sliding pedicle graft for example?)

Thank you again!

 

[DrDentMP]

Hi dentalstudent02,

Sorry for the late reply- post covid patient care commitments are keeping me too busy to get on SDN.

"I am wondering that since we are only using the superficial epithelium layer for the FGG, why we need a full-thickness flap to be raised at the donor site?"

We are not only using the superficial epithelium, if you remember histology from D1 (or undergrad), lamina propria- the mesenchymal tissue is where all the good information processing & tissue response-healing is taking place.

"At the recipient site, would the site need to be prepared so that the epithelium is removed, leaving the underlying connective tissue? Or is it prepared differently?"

You will need to raise a split-thickness flap at the recipient site- cut through the epithelium and leave some lamina propria including periosteum. The periosteum is where undifferentiated "stem" mesenchymal cells are present, important for regenerative procedures.

Also, for the subepithelial CT graft, an online resource suggested that at the recipient site, the connective tissue graft may be left exposed without it being covered by epithelium, since there is a root defect at the recipient site and would not have any epithelium present in that area in the first place. Is this correct?

Yes, that is correct. You can leave it uncovered- "imagine a healing ulcer". Fibroblasts from grafted lamina propria will help in re-epithelialization and form a new epithelium-lamina propria junction at the recipient site. If you have enough attached gingiva you can coronally move the flap up by "scoring" (incising) the periosteum at the base of the flap.

Or does the CT graft need to be covered by epithelium at the recipient site (by a sliding pedicle graft for example?)

"Sliding pedicle" is a flap design that can achieve "grafting" laterally and is done to avoid two surgical wounds - donor and recipient site eg. palate and dentoalveolar.


Hope it helps,

DrDentMP

 

[dentalstudent021]

Hi DrDentMP,

Thank you very much for taking your time to answer my question! it makes more sense now!