Participants with esthetic concern of excessive gingival display who meets the inclusion criteria, will be carried out including history taking, clinical examination and initial therapy.

The initial therapy will consist of periodontal treatment (phase I therapy) including supragingival scaling, subgingival debridement if needed. The mechanical plaque control instructions for each patient include brushing and interdental cleaning techniques. Patients who have inadequate crown length and width ratio or short clinical crown will receive esthetic crown lengthening procedure to adjust gingival levels before being included in this study.

Patients in the intervention group I will take zinc gluconate 50 mg 1 per day to increase zinc level with phytase supplement 176mg (800FTU) 2 tablets per day to give the maximum absorption of zinc, both supplements will be given for 4 days before botulinum toxin injections. Patients in the intervention group II will take zinc gluconate 50 mg 1 per day to increase zinc level, 4 days before botulinum toxin injections.

Patients in the control group will receive the Botulinum toxin injections only Clinical photographs will be taken at baseline, 2 weeks, 1 month, 3 months postoperatively.

Initial examination:

Participants with esthetic concern of excessive gingival display who meets the inclusion criteria, will be carried out including history taking, clinical examination and initial therapy.

The initial therapy will consist of periodontal treatment (phase I therapy) including supragingival scaling, subgingival debridement if needed. The mechanical plaque control instructions for each patient include brushing and interdental cleaning techniques.

Preoperative procedures:

Patients who have inadequate crown length and width ratio or short clinical crown will receive esthetic crown lengthening procedure to adjust gingival levels before being included in this study.

Clinical photographs:

Clinical photographs will be taken at baseline, 2 weeks, 1 month, 3 months postoperatively.

Intervention group I:

Patients in the intervention group I will take zinc gluconate 50 mg (Now food company) 1 per day to increase zinc level with phytase supplement 176mg (800FTU) (Goodphyte company) 2 tablets per day to give the maximum absorption of zinc, both supplements will be given for 4 days before botulinum toxin injections.

Intervention group II:

Patients in the intervention group II will take zinc gluconate 50 mg (Now food company) 1 per day to increase zinc level, 4 days before botulinum toxin injections.

Control group:

Patients in the control group will receive the Botulinum toxin injections only.

Botulinum toxin type A injection:

The patients will be injected at both sides into the "Yonsei point," (3Units) the point that would target 3 muscles responsible for upper lip elevation during smiling, including the levator labii superioris alaeque nasi (LLSAN), in a single injection. This landmark will be identified as the center of a triangle formed by the convergence of the LLSAN, the levator labii superioris (LLS), and the Zygomaticus minor muscles and is located 1 cm lateral to the ala horizontally and 3 cm above the lip line vertically in both men and women (Hwang et al. 2009) and (Nasr et al. 2015).

Postoperative care:

After Botox injection the patients will be instructed to:

1. Remain upright for 4 hours after injection (patients may lie in a reclined position, but not lay flat)
2. Refrain from aerobic exercise that increases the heart rate.
3. Not to massage or manipulate injected areas for 24 hours after injections,
4. Refrain from using ibuprofen, for 24 hours following injection.
5. If bruising appears, apply ice to area for 15 minutes every hour to decrease bruising.

Follow up:

Botox will gradually take effect over 7-10 days with optimum result at 2 weeks. After 2 weeks the patients would come for an additional touch up dose (1 unit at each injection point)

Inclusion Criteria:

1. Patients with excessive gingival display >3mm and with normal clinical crown dimensions.
2. Adults >18 years.
3. Non-smokers.
4. Systemically healthy.
5. Hypermobile lip and mild VME.

Exclusion Criteria:

1. Severe VME.
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 BTX-A or BTX-B (i.e. BTX, 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.
8. Dependent on intact facial movements and expressions for their livelihood (e.g. actors, singers, musicians and other media personalities).
9. Afflicted with a neuromuscular disorder (e.g. myasthenia gravis, Eaton- Lambert syndrome).