Abstract
Rehabilitation of the edentulous patient with atrophic ridges is a problem especially when compounded with a severe prognathic inter-arch relationship. It is difficult to rehabilitate these patients prosthetically without correction of the malrelation of the jaws. The established surgical techniques for correcting combined sagittal and vertical discrepancies of edentulous jaws are often prolonged and complex with attendant morbidity. This article presents a novel, simple method of correction of severe interarch sagittal discrepancy (more than 15 mm) by performing distraction osteogenesis at Le Fort I level using an internal maxillary distraction device. This method is a simple, predictable and stable option for the correction of a severe, unfavourable intermaxillary relation in edentulous patients.
The aim of maxillofacial rehabilitation is to provide the best possible quality of life, which includes restoration of form and function in a stable manner. Severe maxillomandibular malrelations compromise denture function, stability and esthetics . A prognathic ridge relationship transmits an excessive maxillary load to the anterior maxillary denture base, producing increased maxillary alveolar bone resorption and abnormal mobility of the soft tissues. One of the main criteria for preventing this is to provide an orthoalveolar ridge form , which is defined as an idealized alveolar bone positioned in Class I relation, axially aligned with the opposing arch.
Many techniques have been described for vertical augmentation of atrophic ridges; sagittal corrections of malopposed ridges have received less attention. Distraction osteogenesis using internal devices at the Le Fort I level is an accepted method of correcting sagittal discrepancies in cases of dentate maxillary hypoplasia, with stable long term results . There are no reports of using this method to correct sagittal discrepancies in edentulous patients. This article describes a simple and stable method of correcting an edentulous, severely retruded maxilla by Le Fort I distraction using indigenous internal distraction devices.
Patients and methods
Two patients with severe reverse jet of the edentulous arches were reported to the surgical department because they could not be treated satisfactorily with compete dentures without correction of the adverse maxillomandibular relationship. Both patients were conscious of their appearance and had revealed that they thought they had a larger lower jaw, which became evident when their teeth were lost. One patient had rheumatoid arthritis and was taking prednisolone therapy. The protocol for management of these patients consisted of a preoperative diagnostic and prosthodontic phase (including preparation of guiding splint), followed by a surgical phase of Le Fort I osteotomy and distraction, and a follow-up and final restorative phase.
The patients were assessed clinically and found to have reverse jets of 15 and 17 mm. Radiographic assessment consisted of panoramic radiographs, lateral cephalogram and CT scans with 3D reconstruction. Diagnostic casts were obtained and mounted on semi adjustable articulators to evaluate the inter-arch relationship. It was then decided to advance the maxilla surgically at the Le Fort I level using internal distraction devices. For optimal planning, and to assess the progress and the stability of the end procedure, guiding splints were fabricated on both the arches.
To prepare the guiding splints, impressions were taken with relief given in the area of the tuberosity and in the upper buccal flange to accommodate the distraction device. Working casts were poured and articulated at the optimum vertical relation using a semi-adjustable articulator (H2 Hanau, Hanau Eng. Co., Buffalo, NY, USA). A pair of working dentures was prepared with only the anterior teeth arranged and a flat occlusal posterior bite plane. The anterior teeth brought about the desired esthetic component and allowed evaluation of the progress of distraction. The posterior surfaces were left flat for smooth distraction without any occlusal interference. A radiopaque marker was placed in the midline and occlusal plane, so that it would be discernible for radiographic assessment, during distraction.
The operations were performed under general anesthesia with naso-endotracheal intubation. The upper and lower guiding splints were wired to the maxilla and mandible using peralveolar and circum-mandibular wiring. Two maxillary vestibular incisions were made on either side along with a small midline incision with minimal periosteal stripping for access. Standard Le Fort I level osteotomies were performed and the edentulous maxilla downfractured. Two indigenous, intra oral maxillary distractors (A. K. Surgicals, Mumbai, India) were adapted on each side with anchorage on the superior aspect at the zygomatic buttress region and inferiorly fixed to the residual ridge below the transverse osteotomy cut, using monocortical screws ( Fig. 1 ). The vector of distraction was planned to be in an anterio-inferior direction by having a similar angulation during osteotomy and device placement. All patients received ampicillin 500 mg i.v. every 6 h and gentamycin 3 mg/kg/day immediate preoperatively and postoperatively for 5 days.
After a latency period of 5 days, distraction was commenced by turning the distraction rods at a rate of 1 mm daily until the ideal sagittal relationship was achieved. A slight overcorrection of 1 mm was carried out. Lateral cephalograms and panoramic radiographs were taken postoperatively, on completion of distraction, on removal of the device, and 1 year post distraction.
Both the patients treated by intra oral distractors demonstrated marked advancement of the maxilla and correction of the inter ridge discrepancy. Distraction of 16 mm ( Fig. 2 ) was carried out on one patient and 18 mm on the other, both patients undergoing 1 mm more than was originally planned. They were discharged from hospital in 5 days. Postoperative healing was uneventful. The appliances were removed after a consolidation phase of 4 months using the same intraoral incisions and examination of the distracted region revealed good bone formation. Final dentures were fabricated after 2 months of distractor removal. Lateral cephalograms taken 1 year post surgery revealed the stability of the procedure ( Fig. 3 ).
