An interventional study of tunnel technique with a 3D printed PEEK shell to fill the skeletal subnasal depression in Excessive Gingival Display, sponsored by Cairo University. Completed at 1 site in Egypt. Open to participants aged 20 Years to 60 Years. Per ClinicalTrials.gov, last updated 2026-03-23.
Sponsored by Cairo University · Not applicable, Interventional, and Treatment
The aim of the current study is to evaluate the use of a PEEK shell placed in the anterior maxilla placed by tunnel technique in decreasing the gingival display
While lip repositioning has been established as a treatment modality to address excess gum display (EGD) , an often overlooked contributing factor is the lack of lip support. This is often caused by the architecture of the maxilla at the subnasal area. Maxillary overgrowth may give rise to a subnasal skeletal depression producing decreased lip support and marked upper lip retraction during a smile.
Restricting muscle pull by lip repositioning surgery as a treatment option limits muscle movement, however it does not address lip support. In 2018 an alternative intervention was later proposed in a case report study . The technique involves raising a full thickness flap and applying PMMA (polymethyl methacrylate) cement to fill the subnasal depression and limit the upper lip movement. Since its introduction, a limited number of studies have attempted to investigate the technique, however there are not enough studies to support the outcome or the stability of the technique. The aim of the current study is to evaluate the use of a tunnel technique with a 3D printed PEEK (Polyetherether ketone) shell to fill the skeletal subnasal depression
Cairo University is the lead sponsor of 4,780 studies on the registry; 1,427 are open to participants now.
Of its 36 completed or terminated interventional studies of FDA-regulated products, 5 (14%) have results posted.
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Exclusion Criteria:
use of a minimally invasive tunnel technique to fill the skeletal subnasal depression with a PEEK shell in patients with an exaggerated subnasal depression associated with lack of lip support and excessive lip translation
Other: tunnel technique with a 3D printed PEEK shell to fill the skeletal subnasal depression
The area will be anesthetized using infiltration technique with 1.5ml of anesthetic solution containing Articaine Hydrochloride 68 mg/1.7 ml with Adrenaline 0.017 mg/1.7 ml Two bilateral full thickness vertical incisions will be created using a #15 blade. One on each side of the frenum A subperiosteal tunnel connecting the two vertical incisions will be created using a periosteal elevator/tunneling knife until the complete communication between the two ends is established The custom made PEEK framework will be inserted from the incision on one side and eased through until it sits in the subnasal concavity. Once fitted in place the shell will be fixed in place using two mini screws bilaterally, one on each side. The two vertical incisions will be closed by interrupted sutures 6-0 Polyglycolic acid suture material
Gingival display
measured using a periodontal probe in millimeters
Time frame: Day 0 - Month 3 - Month 6
lip translation
measured using a periodontal probe in millimeters
Time frame: Day 0 - Month 3 - Month 6
profile angle
lateral cephalometric xray
Time frame: Day 0 - Month 6
lip length
measured using a periodontal probe in millimeters
Time frame: Day 0 - Month 3 - Month 6
patient satisfaction
measured by a binary Questionnaire ( yes or no)
Time frame: Day 7
Post operative pain
Measured by the visual analogue scale ( 0 no pain, 10 worst pain)
Time frame: Day 7
blinded esthetic assessment
measured by a binary scale (yes or no)
Time frame: Month 3- Month 6
Plan to share: Yes
Supporting information: Study protocol, Csr
This study is completed, as verified in Mar 2026. You cannot join it, but the record below documents what was studied.
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Cairo University