An interventional study of Oral Magnesium Glycinate capsules and ● BoNT-A Injection Alone (Day 0) in Magnesium, Botulinum Toxin Type A and Excessive Gingival Display, sponsored by Cairo University. Enrolling by invitation at 1 site in Egypt. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-10-14.
Sponsored by Cairo University · Not applicable, Interventional, and Treatment
To evaluate and compare the effect of adjuvant oral magnesium supplementation combined with Botulinum Toxin Type A versus Botulinum Toxin Type A alone on the reduction of millimeter gingival display and the duration of clinical effectiveness in patients with excessive gingival display
Excessive Gingival Display , commonly termed "gummy smile," is defined as exposing more than 2 to 3 mm of gingiva during a full, unforced smile. It affects up to 10%-29% of young adults, predominantly females, and frequently leads to patient dissatisfaction with smile aesthetics. While Excessive Gingival Display can originate from skeletal vertical maxillary excess or altered passive eruption, a primary etiology is the hyperfunction of the upper lip elevator muscles (primarily Levator Labii Superioris Alaeque Nasi [LLSAN], Levator Labii Superioris [LLS], and Zygomaticus Minor).
The application of Botulinum Toxin Type A (BoNT-A) has become a minimally invasive gold standard for managing muscular Excessive Gingival Display. However, a major clinical drawback remains its transient duration, requiring repeated injections every 3 to 6 months. Frequent re-injections increase economic burden, patient discomfort, and the potential risk of neutralising antibody formation leading to secondary treatment failure. Strategies to optimize the duration and clinical efficacy ofBotulinum Toxin Type A remain a critical gap in periodontal and aesthetic research.
Rationale for conducting the research:
Botulinum Toxin Type A exerts muscle relaxation at the neuromuscular junction by cleaving SNAP-25 proteins, preventing calcium-dependent acetylcholine exocytosis. Extracellular calcium influx into presynaptic motor axon terminals is the compulsory trigger for acetylcholine release. Physiological evidence demonstrates that Magnesium serves as a natural, competitive calcium channel antagonist at presynaptic nerve terminals. Higher local concentrations of magnesium impair presynaptic entry, thereby suppressing neurotransmitter release.
While zinc supplementation has been studied due to Botulinum Toxin Type A nature as a zinc-dependent metalloprotease, magnesium acts downstream directly at the physiological level of the neuromuscular junction. Co-administering oral magnesium during the neurotoxin uptake window may synergistically decrease presynaptic exocytosis, enhancing initial muscular relaxation or extending clinical paralysis. Given the safety and low cost of oral magnesium, demonstrating its additive benefit would significantly improve patient satisfaction, lower annual treatment costs, and refine non-surgical smile line management.
To evaluate and compare the effect of adjuvant oral magnesium supplementation combined with Botulinum Toxin Type A versus Botulinum Toxin Type A alone on the reduction of millimeter gingival display and the duration of clinical effectiveness in patients with excessive gingival display
Cairo University is the lead sponsor of 4,907 studies on the registry; 1,445 are open to participants now.
Of its 37 completed or terminated interventional studies of FDA-regulated products, 5 (14%) have results posted.
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Exclusion Criteria:
2. Pregnant or lactating females. 3. Patients with inflamed gingiva or gingival enlargement. 4. Inflammation or infection at the site of injection. 5. Patients with known allergy to any of the components of botulinum toxin type A or botulinum toxin type B (i.e. botulinum toxin , human albumin, saline, lactose and sodium succinate).
6. Patients using anticholinesterase or other agents interfering with neuromuscular transmission.
7. Psychologically unstable or who have questionable motives and unrealistic expectations.
Oral Supplement group: Oral Magnesium Glycinate capsules (300 mg elemental magnesium daily, single or divided dose taken with meals). Supplementation starts 4 weeks prior to BoNT-A injection (Day -28) to achieve intracellular steady-state repletion and continues for 4 weeks post-injection (through Day 28), totaling 8 consecutive weeks (56 days) of daily intake.
Drug: Oral Magnesium Glycinate capsules
Botulinum toxin type A Injection Alone group: Botulinum toxin type A Injection Alone group : BoNT-A Injection Alone (Day 0): Identical administration protocol (2.5 Units per side bilaterally at the Yonsei Point, total 5.0 Units) delivered by the same experienced operator without any oral supplementation
Drug: ● BoNT-A Injection Alone (Day 0)
Oral Supplement: Oral Magnesium Glycinate capsules (300 mg elemental magnesium daily, single or divided dose taken with meals). Supplementation starts 4 weeks prior to BoNT-A injection (Day -28) to achieve intracellular steady-state repletion and continues for 4 weeks post-injection (through Day 28), totaling 8 consecutive weeks (56 days) of daily intake
BoNT-A Injection Alone (Day 0): Identical administration protocol (2.5 Units per side bilaterally at the Yonsei Point, total 5.0 Units) delivered by the same experienced operator without any oral supplementation.
Change in gingival display
Change in gingival display BY Ruler in Millimeters
Time frame: at 6 weeks
Assessment of Pain by visual analogue scale
The left end represents no pain (0 mm), and the right end represents the worst possible
Time frame: at 6 weeks
Plan to share: Yes — It will be available if it needed
Supporting information: Study protocol, Informed consent form
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Studies of the drug tested here: Magnesium diglycinate