**Author details**

**9.9. Lip dysfunction**

564 A Textbook of Advanced Oral and Maxillofacial Surgery Volume 2

**9.10. Bone resorption**

implant must be removed.

relaxes and softens.

**10. Summary**

**9.11. Postoperative asymmetry**

Altered lip function occurs because dissection can interfere with the muscles responsible for smiling mimetics. Other factors include edema, interposition of a solid implant which stretches the muscles of the midface, or interference with the facial nerve during dissection over the zygomatic arch. The edema can cause dysfunction in the muscles of the lips resembling facial nerve dysfunction. When dysfunction is due to muscle displacement, it usually takes 1–3

Bone erosion under alloplastic implants was a significant problem with early implants. It was often attributed to foreign body reaction between the implant and the bone or to pressure from the mentalis muscle against the implant. Improper implant positioning, pressure due to an oversized implant, subperiosteal placement and hardness of the implant were also considered.

The resorption from anatomic malar and chin implants is minimal and self-limiting. Bone erosion occurs less with anatomic extended implants because of greater distribution of the pressure forces over a broader anatomic area. Resorption appears to occur in the first 12 months after placement but can appear radiographically as soon as 2 months. Labial incompetence and hyperactive mentalis lead to pressure and migration of the implant superiorly onto the thinner bone of the alveolus, which predisposes to resorption. When severe resorption is present, the

Asymmetry is more likely to be noticed in malar implants. It is usually caused by initial malposition or by creation of asymmetric bilaterally dissected spaces. It can also be the result of unrecognized preoperative skeletal or soft tissue deficiencies. It is important to point out preexisting asymmetry before treatment selection. Although major asymmetries require a second surgery, minor asymmetries have a natural tendency to adjust and correct themselves over a 6-month postoperative period as healing progresses and the tissue around the implant

Loss of volume and volume shift occur in all regions of the face and neck and contribute to the aged appearance. Volume replacement and contour augmentation of the face are the essentials of facial cosmetic surgery. The development of less invasive volume replacement procedures has been an evolution in achieving better aesthetic results. These procedures include lifting

Facial volume augmentation by using facial implants is a very safe procedure that is used widely for facial rejuvenation which can be used concomitantly with other rejuvenation

procedures, injectable fillers, autologous fat transfer, and facial implants.

months for the muscles to reattach and the capsule to become soft and distensible.

Farzin Sarkarat\* , Behnam Bohluli and Roozbeh Kahali

\*Address all correspondence to: sarkarat@hotmail.com

Department of Oral and Maxillofacial Surgery, Bouali Hospital, Islamic Azad University of Medical Sciences, Tehran, Iran
