Most patients consider facial contour reconstruction as simply reducing the face width but ignore the fact that the chin can also affect the length and ratio of the entire face. Based on clinical studies and observations, Dr. Chuang found that the chin is located on the mass center, and is the lowest point of the face; its length, forward protrusion, or backward retraction can affect the ratio of the entire face, which will even weaken the visual perception of facial width. Therefore, upon performing facial bone reduction, the proper length and shape of the chin should also be considered to match the new contour of the face. In such cases, the possible visual result of a slimmed and pointed face provided by elongating or sliding the chin forward should be evaluated, and the corrective results for a long face should be provided by shortening or sliding the chin backward. Generally, genioplasty can complement the result of cheekbone or jaw surgery and is worth being performed as either an individual surgery or a combined procedure with other facial bone reductions. Besides, chin and teeth occlusion are also closely related; corrective orthodontics can also affect the contour and length of the chin in the future. Accordingly, before performing any chinbone surgery, surgeons must evaluate whether patients with malocclusion of the teeth should undergo functional correction first or whether only esthetic chinbone adjustment related to jaw appearance is necessary to obtain a stable and long-term result.
The standard for the length of the chin is subjective, and everyone has his/her own preferred contour; therefore, when making a preoperative evaluation for chinbone surgery, surgeons should always take into account not only the predefined ratios of face but also the requirements of patients. Generally, the preferred standards for the appropriateness of chin length are that the mouth is located on the one-third of the lower face (distance from the base of the nasal columella to the bottom of the chin) and that the ratio between the distance from the mouth to the nose and the distance from the mouth to the chin point should be 1:2. If the ratio is lower than this, the length of the chin can be defined as too short; on the contrary, it can also be too long. In the side view of the face, it is better if the nose tip, upper (or lower) lip, and chin side points are perfectly aligned (E line).If the chin point is beyond this line, the chin can be protruded (over-bite or long mandible); on the contrary, the chin can be retracted (short chin or receding mandible). Although there are no rules for the width and shape of the chin, women prefer a smaller and sharper chin, which is narrower than the mouth in width, and a pointed curved shape that will look feminine and sweet; in contrast, men like a bigger and stronger chin, which is wider than the mouth, and a slightly square shape that will look more masculine. Besides the above parameters, patients should think about the fact that chin length will affect their facial attractiveness. For example, a person with a longer chin will look mature and prudent, and one with a shorter chin will look sweet and cute. Accordingly, all these factors have to be evaluated before undergoing chinbone surgery.
Currently, the most popular chin surgery is chin augmentation with a Medpor or Sili-Tex implant. Although this surgery will easily correct the short or retracted chin problem, it still cannot completely replace chinbone surgery in patients who are not willing to accept prostheses or implants. Furthermore, chinbone reduction is the only solution to treat patients with congenital chin hypertrophy such as a fleshy chin, overly wide chin, asymmetric chin, or even elongated chin. Therefore, Dr. Chuang provides the following chinbone surgeries: