Orthognathic Surgery for Correction of Skeletal Class III Malocclusion Using Osseointegrated Dental Implants: A Clinical Case Letter

An idealized alveolar bone positioned in class I relation axially aligned to the opposing arch is the concept for optimal dental restoration,¹  even if there are frequent discrepancies between the jaws, such as skeletal class III malocclusion with an increase of older patients seeking correction of their jaw deformities.²  Usually, in such a case, dental implants are inserted after orthognathic treatment as it is difficult to plan the postsurgical occlusion before surgery.²  Kim et al. gave evidence that implant placement after orthognathic surgery enhances marginal peri-implant bone loss as well as the incidence of peri-implant mucositis and peri-implantitis compared to a nonorthognathic control group.³  The authors concluded that this deteriorated osseointegration may be due to the regional acceleratory phenomenon (RAP) after the noxious stimulus obtained by the surgical procedure.⁴  Here, a shift of osteoclasts and osteoblasts was proposed, leading to an osteopenic effect.^3,5  In accordance, special considerations for peri-implant soft and hard tissue stability are recommended in patients who have had prior orthognathic surgery.³  It is also possible to place the implants before and to use them for the surgical procedure. For example, Depprich et al. treated a cleft palate patient with maxillar atrophy with bilateral sinus lifting, placement of dental implants and subsequent Le Fort I osteotomy to obtain an ideal jaw position.⁶  Advantages of this technique are that the respective implants can be immediately loaded after surgery and therefore be used for exact planning and interocclusal securing.

In this clinical letter, a technique for correction of class III malocclusion using several osseointegrated implants and computer-aided design/computer-aided manufacturing (CAD/CAM) milled, pre-planned fixed dentures in the maxilla by means of Le Fort I osteotomy is described.

In both cases, the implants were osseointegrated, and the peri-implant soft tissue was healthy. Due to skeletal malocclusion in the maxilla and facial esthetic considerations, prosthodontic treatment with fixed prostheses was deemed unsuitable; options including custom-made abutments were discussed with the patients and both opted for a surgical solution mostly due to esthetic reasons such as the facial profile and reduction of the nasolabial folds. Presurgical evaluation consisted of digital photographs as well as cephalometric and panoramic radiographs. A face bow was recorded and transferred into mounted study casts, and diagnostic waxing was performed. After clinical and dental cast analysis, surgical correction of the implants' position was simulated ex vivo on the mounted models using Le Fort I osteotomy as indicated for orthognathic cases.⁷  Differences before/after the simulation were controlled with standardized digital photographs. Prior to surgery, definite abutments and CAD/CAM milled long-term temporary restorations that were manufactured on the ex vivo models were incorporated. For surgical procedures, a horizontal incision in the buccal sulcus from the first premolar to the contralateral premolar was carried out, and the facial bone was exposed while elevating a full-thickness mucoperiosteal flap. The horizontal osteotomy procedure was carried out at least 5 mm away from the root apices using a piezoelectric scalpel (Piezosurgery, Mectron Medical, Cologne, Germany) as well as several chisels. The osteotomy was completed from the pyriform rim to the posterior extent of the zygomatic buttress in the lateral wall of the maxilla, in a plane parallel to the Frankfort horizontal plane as described in the literature.³  Following the down fracture of the maxilla, osteosynthesis was conducted in occlusion achieved with the prefabricated prostheses. Due to the exact fitting of the temporary restoration that was securing the occlusion, no further intermaxillary fixation was carried out. The surgical site was sutured with 4-0 Vicryl. The patients received intravenous antibiotics for 2 days and amoxicillin oral (1 g twice a day for the following 3 days) as well as 0.12% chlorhexidine gluconate rinses (twice a day for 7 days). The sutures were removed after 10 days.

A 45-year-old female patient presented with 4 dental implants in the upper jaw, which had been in situ for 10 years but could not be used by her dentist due to the pronounced reserve of the upper jaw (class III malocclusion; Figures 1, 2a and b). The patient reported a high level of psychological distress and, instead of the insufficient removable denture, wished for a fixed denture that had been rejected by her dentist previously. Additionally, she inquired whether an improvement of the midface profile was possible. After discussing the treatment options, a decision was made toward a combined surgical-prosthetic procedure using the osseointegrated implants. Individual abutments and a CAD/CAM-milled long-term temporary restoration were manufactured (Poly-Temp, Ceramill, Amann Girrbach GmbH, Pforzheim, Germany) and incorporated as described already. This restoration served as a splint to determine the definitive corrected jaw relation and occlusion for osteosynthetic fixation (Figures 3, 4, 5a and b). No further intermaxillary fixation was needed. After an uncomplicated healing period of 3 months, the temporary restoration (Figure 6) was transferred to a definitive prosthesis (Ceramill ZI, Amann Girrbach; IPS e.max Ceram, Ivoclar Vivadent, Schaan, Liechtenstein) (Figure 7). After a follow-up of 5 years, no relapse was seen.

A 50-year-old male patient asked for prosthetic restoration of 5 implants placed in the maxilla. During clinical and radiological examination, a pronounced class III malocclusion, a frontal crossbite, together with a reduced residual dentition and an insufficient removable prosthesis, was found in the upper jaw. In the mandible, a bilateral free end situation with a likewise insufficient interim prosthesis was seen (Figures 8 and 9). Due to additional deficits in the patient's facial profile, a combined surgical-prosthetic procedure was planned after obtaining informed consent and discussing the treatment options. Individual abutments manufactured were created for receiving an individual CAD/CAM milled maxillary temporary restoration (Poly-Temp, Ceramill, Amann Girrbach) as shown already (Figures 10a and b). Again, the restoration was inserted before surgery and was used for intraoperative and postoperative securing of the jaw relation and occlusion (Figure 11). Therefore, analogous to patient 1, no further intermaxillary fixation was necessary. The postoperative healing process proceeded without complications (Figure 12a and b), so that the final prosthetic restoration using telescopic crowns in the upper and lower jaw could be inserted after a bony consolidation period of 3 months (CARES, Straumann, Basel, Switzerland; Sinfony, 3M, Seefeld, Germany) (Figure 13). Artificial gum (Ceramage, Shofu, Japan) was used for the definitive removable prostheses due to esthetic considerations. It allowed a more natural appearance and position of the anterior teeth (tooth length, form, arrangement, midline). The other teeth were restored with full ceramic single crowns and bridges (zirconium oxide frameworks Ceramill ZI [Amann Girrbach] and IPS e.max Ceram [Ivoclar Vivadent] layering ceramics). After a follow-up of 4 years, no relapse was seen.

This is the first case series of correction of skeletal class III malocclusion using several osseointegrated implants with CAD/CAM-milled long-term temporary restorations as splints for surgical relocation of the upper jaw. The implants helped for exact planning of the orthognathic surgery to stabilize the occlusion. It was thus possible to dispense with an intermaxillary fixation. Moreover, the patients left the hospital with fixed and fitting dentures in their new position. The presented stable long-term follow-up of 4 to 5 years indicates predictable results of this technique.

Le Fort osteotomy for preprosthetic correction of interarch relationship has shown to be a reliable treatment option for the atrophic maxilla, mostly followed by implant placement.⁸  In accordance, Apaydin et al. reported this procedure together with distraction osteogenesis in a young woman with amelogenesis imperfecta and inserted the implants afterwards.⁹  Ribeiro-Junior et al. described a similar method in a 40-year old man that was augmented via iliac crest bone in the maxilla followed by implant placement followed by Le Fort I osteotomy.¹⁰  In other reports, Le Fort I osteotomy and implant placement were conducted simultaneously.^11,12  Even so, implant insertion closely associated to orthognathic surgery seems to be a risk factor for peri-implant complications.^3,13  Similar to the presented cases, Abdel-Azim et al. conducted a dental restoration in a patient with skeletal transverse and anteroposterior deficiencies via maxillary bone grafting, sinus floor elevation, placement of implants before Le Fort I osteotomy, and surgically assisted rapid palatal expansion using maxillary provisional prosthesis.¹⁴  However, the technique should be employed in selected cases only as preplanning of the restoration and Le Fort I osteotomy are technically demanding. Besides, the surgical step has a certain morbidity and unfavorable complications such as fractures, oroantral fistulas and bone exposure are described.^15,16  Mostly, the indication is to correct an unfavorable intermaxillary relationship together with the need of an improvement of the facial profile.

We present a case series of correction of skeletal class III malocclusion using implant-supported restorations as splints and fixation for Le Fort I osteotomy. The technique described allows renewal of the interalveolar relationship together with predictable results, and creates a fitting environment for dental restoration in a comparable short treatment time without the need for intermaxillary fixation.

Abbreviations

CAD/CAM:

computer-aided design/computer-aided manufacturing

The authors declare that they have no competing interests.