Reconstruction of 3D defects in the anterior maxilla are challenging in terms of both restored function and esthetics. The Chairman of the Department of Oral & Maxillofacial Surgery at Umeå University in Sweden sends us the following treatment report.
A24-year-old female was wounded by a gunshot during a robbery in a store. The 9 mm bullet, fired from the distance of a few meters, resulted in a significant 3D-defect in the left upper lip and maxilla. The bullet penetrated the throat and was stopped by the cervical vertebrae a few mm from the spinal cord. The 24-year-old Estonian female was seen in a consultation visit in Tallin by Dr. Juha Peltola, an oral & maxillofacial surgeon in private practice in Helsinki, who referred the patient for treatment planning — and if possible, treatment — to the Department of Oral & Maxillofacial Surgery, Umeå University Hospital.
The initial treatment planning was done by Dr. Peltola together with me and Dr. Hans Nilson, the planned restorative dentist from the Department of Prostetic Dentistry at Umeå.
The first step was a contact with Nobel Biocare to help with the funding of travel expenses, laboratory costs and components. Financial negotiatons were carried out with the University Hospital and The Dental School in order for us to be able to complete the planned treatment at no cost to the patient, who was unable to otherwise finance it.
Bone graft first
Under general anesthesia, a bone graft was harvested from the anterior left iliac crest and placed in the defect in order to provide good bone architecture for the later placement of implants.
Three months later, a CT with a radiological guide was performed in Helsinki and the implant placement was virtually planned with Nobel- Guide treatment planning software in collaboration with Matts Andersson and Andreas Pettersson at the Nobel Biocare office in Gothenburg.
We placed the implants in the office of Dr. Peltola in Salora, Finland, with help from the surgical guide derived from the preoperative Nobel- Guide planning. At this point, the implants were placed in good bone, with a nice bone architecture, yet remote from the planned bridge!
Placement of the implants—as well as the planned final navigation of the anterior maxillary segment, including the grafted bone and the three implants— was all performed in the virtual 3D environment. The implants were allowed to heal for two months before the distraction surgery was initiated. The external distraction device was custom-designed by the Department of Early Development, Nobel Biocare in Gothenburg.
A distraction device
The custom designed distraction device was divided in two parts. A small Procera bridge connected the three implants in order to create a system of two rods which were parallel and in the direction of the planned vector.
The second part of the distraction device was incorporated in the temporar bridge, which was retained with temporary cement, as a splint, on the posterior dentition.
The third surgical phase was performed in Umeå under local anesthesia and I.V. sedation. The anterior maxillary segment was osteotomized and the bone segment, including the three implants, was mobilized. Then the different parts of the distraction device were assembled, the temporary bridge was cemented to the posterior maxillary teeth, and the surgical wound was closed with sutures.
The patient went home to Tallinn the day after surgery and the active distraction was started ten days after the surgical intervention. The active distraction over ten days was assisted by the patient’s dentist in Tallin and was followed by two months of consolidation before the distraction device was removed, and the patient could receive a temporary bridge in Tallin.
Then the patient came to Umeå for the processing of the final bridge, which was temporarily provided. After another few weeks, she returned again for the final adjustment of the bridge. After delivery of the corrected bridge we did the final surgical correction of the upper lip.
Note on technique
According to this treatment protocol, we place the implants in the bone graft to allow optimal placement in the bone regardless of the final implant position. If the implants are correctly positioned in relation to each other, the bone segment (including the implants) can later be transported to the final correct position for the temporary bridge. This requires treatment planning performed in a virtual 3D environment. The sequence of treatment provides a number of benefits.
The distraction device, retained by the implants, can be removed in a noninvasive way as the device is extra- mucosally positioned. The distraction technique increases not only bone tissue but also mucosal volume. With the correct technique, the width of the keratinized mucosa can be increased both on the newly formed alveolar process and around the implants.
More to explore:
Breine U, Brånemark P-I. “Reconstruction of alveolar jaw bone.” Scand J Plast Reconstr Surg 1980: 14: 23- 48.
Lundgren S, Sennerby L (eds). Bone Reformation: Contemporary Bone Augmentation Procedures in Oral and Maxillofacial Implant Surgery. Quintessence, Berlin, 2008.
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