Rigid fixation with screws is preferred to prevent implant mobility, over-correction, asymmetry, or irregularities
The position of the implant is determined by the direction of the improvement to be achieved
Implants for augmentation of mandible are also fixed with multiple screws (a) preop, (b) after insertion of medpor implant and fixation with screws
The ramus and body of the mandible is exposed through an intraoral incision that is made at about 1 cm above the sulcus. Dissection in the subperiosteal plane proceeds to detach the muscle from both the inferior and posterior border of the mandible. Fixation with multiple screws in proper position is critical (Fig. 12.4). Implant and screw failure may result from excessive pull by masseter muscle or external pressure. Selection of implant shape and material is made according to the specific needs of the patient. If lateral volume is deficient, simple silicone implant is good enough. If lower border of the mandible is lost, rigid implant made of Medpor® is recommended. If there is a larger lower border defect requiring a buttress to resist the muscle pull, Medpor® implant with lower border sleeve is recommended (Fig. 12.5). Rigid fixation is critical in this case.
Medpor® implant with lower border sleeve
Suction drains are not routinely used as amount of bleeding is usually minimal. However, if there is bleeding, strict hemostasis and/or drain insertion is necessary to prevent hematoma formation and infection. Chlorhexidine gluconate mouthwashes are prescribed for use 3 days postoperatively. Intravenous antibiotics are administered perioperatively and oral antibiotics are prescribed for 1 week after surgery.
Key Technical Points
Rigid fixation is recommended with proper pocket dissection to prevent displacement and visible margin.
Aseptic technique is critical to prevent the infection. Be careful not to contaminate the implant with too many test insertions.
Selection of proper implant is based on preoperative evaluation and patient’s request and surgeon’s experience.
Mentalis muscle should be carefully repaired and controlled to have a natural lip and chin shape.
A 24-year-old woman complained of deficient projection of chin.(Fig 12.5a) She wanted improvement of the profile. Considering ideal profile through lateral X-ray (Fig 12.5b), 8mm sized silicone implant was inserted through intraoral incision and fixed with two screws. (Fig 12.6b) The chin projection was improved markedly after the surgery. (Fig 12.6a).
(Case 1) Preoperative photo (a) and lateral X-ray (b) Suction
(Case 2) Preoperative (a) and postoperative (b) photo
Mandibular angle augmentation
A 28-year-old man complained of feminine appearance because of lack of mandibular angle and wanted more strong jaw line. (Fig 12.7a) He underwent a medpor implant insertion surgery at angle. Through the oral incision, medpor implants were inserted bilaterally and fixed with two screws to prevent instability. After the surgery, his jawline was improved definite and masculine (Fig 12.7b).
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