Smile surgery or smile reconstruction is a surgical procedure that restores the smile for people with facial nerve paralysis. Facial nerve paralysis is a relatively common condition with a yearly incidence of 0.25% leading to function loss of the mimic muscles. The facial nerve gives off several branches in the face. If one or more facial nerve branches are paralysed, the corresponding mimetic muscles lose their ability to contract. This may lead to several symptoms such as incomplete eye closure with or without exposure keratitis, oral incompetence, poor articulation, dental caries, drooling, and a low self-esteem. This is because the different branches innervate the frontalis muscle, orbicularis oculi and oris muscles, lip elevators and depressors, and the platysma. The elevators of the upper lip and corner of the mouth are innervated by the zygomatic and buccal branches. When these branches are paralysed, there is an inability to create a symmetric smile. Smile surgery is performed as a static or dynamic reconstruction. An example of static reconstruction is upper and lower lip shortening or thickening with commissure preservation. Dynamic smile reconstruction procedures restore the facial nerve activity. Historical background The first known surgical repair of an injured facial nerve was performed by Drobnick in 1879, who connected the proximal spinal accessory nerve (innervates trapezius and sternocleidomastoid muscles) to the paralysed facial nerve. More symmetrical features were the result. In 1971 a new technique for facial nerve reconstruction was introduced, as Scaramella and Smith reported on the technique of cross facial nerve grafting (CFNG) for reconstruction of a coordinated smile in unilateral facial paralysis cases. Harii et al. for the first time used a free muscle transfer in combination with a nerve transfer in 1976. Eight years later, Terzis introduced the "babysitter" procedure, which consists of a combination of CFNGs and a simultaneous partial hypoglossal to facial nerve transfer. In 1989, Zuker et al. suggested the use of the masseteric nerve as possible donor nerve for innervation of the transplanted muscle in patients with Moebius syndrome. Indications The main indications for dynamic smile reconstruction are unilateral or bilateral facial paralysis due to acquired and congenital causes. Trauma, Bell's palsy and tumour extirpation are examples of secondary or acquired facial paralysis. Bell's palsy or idiopathic facial paralysis is a condition which leads to facial paralysis, however, without a known cause. It has an acute onset and is mostly self-limiting. But if spontaneous recurrence