Date of Award

Spring 2021

Document Type


Degree Name

Master of Science (MS)





First Advisor

Brunner, Mark

Second Advisor

Dentino, Andrew

Third Advisor

Guentsch, Arndt


Background: Lip repositioning (LR) is a conservative and reversible surgical method for correcting excessive gingival display (EGD). Purpose: The study aims to compare two LR techniques. The objectives include 1) comparing the amount of gingival display reduction (GDR) after LR without (Group 1) and with (Group 2) myotomy, stratified in accordance with the etiology of the EGD 2) Comparing the gingival display rebound (GDRB) 3) compare subject satisfaction and morbidity. Methods: After obtaining IRB approval, 20 human subjects with EGD (measured apical to the CEJ of #9) were randomly allocated for surgery without and with myotomy. Pre-operative, diagnostic information were collected to determine the patient's single or combined EGD etiology. Pre and post-operative measurements (up to 6 months) (gingival display [GD], lip length [LL], and vermillion border length [VB]) were taken with a digital caliper. The primary outcome parameters were the GDR, change in LL, change in VB, and GDRB. Secondary outcomes were assessed with a smile questionnaire and a visual analogue pain scale (VAS). The obtained data were processed in SPSS (version 25.0) using ANOVA for metric parameters and xyz for scaled parameters. A p-value of < 0.05 was set as to be statistically significant. Results: Combining both procedures, the results of the primary outcomes showed a total average GDR of 2.63mm (SD = 0.291 mm); a total average decrease in LL of 1.58mm (SD 0.592mm); a total average increase in VB width of 1.1mm (SD = 0.211mm). The differences in GDR and GDRB between the two surgical techniques were statistically significant with the myotomy group showing a greater average GDR and less GDRB. In addition, the differences between the two procedures were statistically significant for patients with degree I & 2 VME, HL, and all 4 etiologies. There were no statistically significant differences in patient satisfaction nor patient morbidity between the two surgical procedures. Conclusion: LR with and without myotomy are considered treatment options for treating patients with EGD. Our study suggests that performing a myotomy increases the overall GDR achieved, deters GDRB, and improves results in certain etiologies.

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