Evaluating Lip Repositioning for the Treatment of Excess Gingival Display With and Without Pretreatment With Botox

Since the introduction of the lip repositioning procedure by a number of modifications to the technique have been introduced. All these modifications were made to prevent the main complication of lip repositioning surgeries 'relapse'. Relapse was found to occur in 8% of the cases treated .

Botox injections have been suggested as a possible treatment for cases with relapse Botox acts by blocking muscular activity, however, Botulinum toxin technique has a transitory effect (6-7 months). . By combining Botox as a pretreatment and lip repositioning surgery, Botox injections maybe a useful adjunct in improving and stabilizing the results of achieved, by paralyzing the muscles during the healing period.

There are no studies, to the investigator's knowledge, exploring the use of botox combined with lip repositioning to decrease muscle pull and therefore decrease the relapse.

Normal gingival display has been defined by as the gum exposure between the inferior border of upper lip and gingival margin of anterior central incisors when smiling. An exposure of gingiva around 0-2 mm when smiling, and 2-4 mm of the maxillary incisor edges when the lips are at the rest state are considered as acceptable. While more than 2 mm of gingival exposure when a person smiles is stated by experts as an excessive gingival display, or what is known as "Gummy Smile",which is more of a descriptive term than a diagnosed condition, and affects a notable proportion of the population, especially women who are affected more than men.

Many studies have stated the main causes of excessive gingival display, presenting the most important factors which may lead to having a gummy Smile. The study of Roe described that lip length and the upper lip mobility rate are the main contributing factors. The previous research stated that the exposure of teeth and gingiva depends on the integrated effects of a number of variables (increased muscle capacity, vertical maxillary excess, greater inter-labial gap at resting position, and the amount of over-jet and over-bite). Pausch \& Katsoulis mentioned that abnormal gingival and maxillary anterior teeth display may take place due to numerous anatomic or functional factors, either hereditary or inborn. A narrow upper lip, an irregular eruption of teeth, excessive protuberance or vertical maxillary growth, and hypermobility of the maxillary lip and elevator muscle are common reasons for a gummy Smile. In fact, several contributing factors are affecting individuals to have a gummy Smile. Sometimes one of them is presented, although in some cases more than only one cause can be seen. Correct diagnosis of the reason leads to a proper treatment plan.

Excessive gingival display can be managed by a variety of procedures. These procedures include surgical and non-surgical methods The underlying cause of excessive gingival display or gummy Smile has the main effect on the type of procedure that will be performed.

Eligibility Criteria:
Inclusion Criteria:

1. Gummy smile more than 3mm.
2. Adults \>18 years.
3. Non-smokers.
4. Patients with healthy systemic condition
5. Normal clinical crown dimensions.
6. Good oral hygiene.

Exclusion Criteria:

1. Natural dentition upper anterior
2. Pregnant or lactating women.
3. Patients with inflamed gingiva or gingival enlargement.
4. Inflammation or infection at the site of injection.
5. Patients with allergy to botulinum toxin, lactose, and albumin.
6. Concurrent use of aminoglycoside antibiotic that enhances the action of the toxin. (Jaspers, Pijpe, \& Jansma, 2011)
7. \< 3 mm attached gingivae that might create difficulties in flap design, stabilization and suturing.
8. Patients using anticholinesterase or other agents interfering with neuromuscular transmission