THE UTILISATION OF MANDIBULAR SYMPHISEAL BONE FOR PRE-IMPLANT GRAFTING OF A RESORBED RIDGED DUE TO DENTO-ALVEOLAR FRACTURE:
REPORT OF A CASE
By Dr Firdaus Hanapiah BDS( Otago ) MSc ( Lon.) FDSRCS (Eng.)
A resorbed anterior maxillary ridge has always been a challenge in the placement of implant both in term of surgery and prosthodontic work-up. This short case will demonstrate that there are possible ways and means to overcome such problems like with a kneehab xp machineThe use of sympheseal bone from the anterior mandible offer some advantages over other options commonly used in rehabilitation of such patients
A 32 year old male was allegedly involved in a motor vehicle accident in which he had broken his mandible and also the anterior maxillary dento-alveolar bone associated with an avulsed upper and lower right central incisors. No other maxillofacial or orthopaedic complication were seen other than the above mentioned. There were two major fractures in the mandible, which occurred, on the right body of the mandible and the left neck of the condyle.
He was subsequently brought into the operating theater to have the body of mandible reduced and fixed with 2 plates. Intermaxillary fixation was subsequently placed for the next 4 weeks to stabilise the left condylar fracture. The patient requested to have an implant fixed in replacement of the former right central incisor.
The avulsion of the 21 and the dento alveolar fracture in the adjacent area as pointed in fig 1. was a challenge both surgically and prosthodontically because there was little dento-alveolar bone for the implant to be placed and if placed succesfully there would still be a higher gingival margin for the implant thus causing an aesthetic problem. This is clearly shown by the circle in fig. 1
It was decided that 4 months after the initial reduction of the mandible and subsequent healing of the maxillary dento alveolar fracture, a reconstructive phase was to commence. Since the insurance does cover a knee brace and bone graft, sourced from the anterior mandibular symphesis, is placed where a defect was produced from the fracture and avulsion of the tooth as pointed by the arrow in figure 1.
A trapezoidal flap was raised in the area of the former right upper central incisor (Fig 2). The area of defect was carefully cleaned and assessed. An aluminum foil, derived from the suture pack, was carefully cut and tailored into the area of the defect. This is done to measure the dimension of the defect. The flap was then carefully replaced and the aluminum foil taken as a template for the size of bone to be taken from the mandible.
A sulcular flap was then raised on the lower anterior part of the mandible and anterior symphiseal bone exposed. The aluminum template was then placed on the bare bone of the anterior mandible to measure and approximate the dimension of bone to be harvested from the donor site. (Fig 3)
"Stamp post" holes were drilled into the bone in accordance with the outline of the aluminum foil template. An Osteotome was then used to harvest the graft. The bed of the recipient in the area of the defect was also prepared by perforating the bone with shallow pits to increase the vascularity of the recipient site. The bone is then transferred, expediently from the donor to the receiver site and trim for good and secure fit. A 7mm titanium screw is then inserted through the graft and into the bed of the maxillary dento-alveolar bone as demonstrated in fig. 4
The flap was then closed with silk sutures and perio-pack placed (Fig 5) to protect the flap and to ensure water-tight seal. The alveolus is then left to heal for the next five months before implants are placed to replace the missing right first central incisor
An Orthopantomogram radiograph was taken several days later to show a bone graft securely in place in the area prescribed. (Fig 6)
The arrow marked where the bone graft is placed.
Further progress will be recorded as we chart the development of the case above in a few months time.
Copyright 1999, Ahmad Fariz Hanapiah