The patient initially presented to the graduate orthodontic program at the University of Michigan School of Dentistry at 14 years of age with complaints of poor dental esthetics with diastema and abnormalities in the shape/size and alignment of front teeth, speech issues, and multiple missing teeth. Diagnosis of oligodontia was reported in one or more of her siblings. On examination, maxillary and malar hypoplasia was noted, along with a concave facial profile, maxillary asymmetry, a skeletal Class III malocclusion, and oligodontia (Fig. 1a–e). A panoramic radiograph confirmed the absence of teeth #1, 2, 3, 6, 7, 10, 11, 14, 15, 16, 17, 18, 31, 32, and the presence of retained primary teeth D, E, G, H (Fig. 1f). The lateral cephalometric radiograph and tracing revealed the underlying skeletal Class III nature of her malocclusion. (Fig. 1g). Since no abnormalities in other parts of the body were seen on exam, including nail, skin, hair, salivary and sweat glands, the patient was diagnosed with non-syndromic oligodontia with maxillary hypoplasia and malar deficiency. The patient was referred to the department of oral and maxillofacial surgery at the same institute for further evaluation. It was determined that orthognathic surgery was necessary to treat her maxillary hypoplasia and malar deficiency.
As a result of the compensatory response to the skeletal Class III condition, the patient had flared maxillary incisors with diastema (Fig. 1c, d). Thus, pre-surgical orthodontic treatment was carefully planned with multidisciplinary inputs to facilitate future orthognathic surgery and prosthodontic needs (Fig. 2). The goal of this phase of treatment was to retract and upright the patient’s anterior teeth into the ideal position in the alveolar base, and allow a proper occlusion after the jaws are aligned. As expected, the pre-surgical orthodontic decompensation treatment closed the diastema and led to a slight reverse overjet with coincident dental to facial midlines (Fig. 2c, d). Next, at the age of 17, a high Le Fort I maxillary osteotomy was performed to advance the maxilla. This operation successfully improved the midface projection (Fig. 3a, b), achieved positive overjet and overbite (Fig. 3c). Post-operative radiographs demonstrate the new maxillary position with fixation at the pyriform rims and zygomatic buttresses (Fig. 3d, e).
After the orthognathic surgery, orthodontic treatment was continued to refine the alignment, root parallelism, and coordinate the arches with guidance from the prosthodontist. One goal of post-operative orthodontic treatment was to provide the optimized restorative space for implant prostheses. Diagnostic teeth set-up was performed to confirm the proper space and project future teeth position (Fig. 4a). The planned tooth size and shape were communicated with patient to her satisfaction. Thereafter, retained primary teeth C, D, G, and H were extracted and a particulate allograft was used for ridge preservation with a cross-linked collagen membrane. Interim maxillary partial denture was fabricated for the esthetics and maintenance of space (Fig. 4b, c). A few months later, the patient presented with inadequate ridge width in the edentulous maxillary ridge areas. Additionally, the alveolar ridge surrounding adjacent permanent teeth was also very thin. The maxillary rigid fixation was noted to pose a potential interference to future implant placement and apical extension of bone graft material. Therefore, the maxillary anterior rigid fixation was removed and an allograft block grafting was performed at sites #6, 7 and 10, 11 and secured with lag screws (Fig. 4d, e). The particulate allograft with the use of recombinant human bone morphogenetic protein-2 (rhBMP-2) (Infuse™ bone graft) was applied peripherally on either side of the block graft.
Four months later, a cone beam computer tomography scan was obtained and an implant planning software (NobelClinician, Nobel Biocare, USA) was used to determine implant position and size (Fig. 5a–c). Given the limited mesio-distal space, 3 mm diameter implants were chosen to preserve blood supply and ensure adequate space between implants and adjacent tooth roots. During surgery, lag screws placed previously were removed, 3.0 × 13 mm implants (Nobel Active) were placed at sites #6 and 11, and 3.0 × 11.5 mm implants (Nobel Active) were placed at sites #7 and 10 (Fig. 5d). Sub-crestal implant placement was achieved with 30 Ncm of torque. Five months later, the stage 2 implant surgery was carried out to expose the implants, which were protected with healing abutments thereafter.
The provisional implant crowns were used to facilitate the establishment of desirable emergence profile of the transmucosal tissue around the implant restorations (Fig. 6a). After 2 months, the transmucosal tissue matured to satisfactory extent (Fig. 6b) and the permanent implant prosthesis fabrication was thus initiated. Custom impression copings were used to register and transfer the shape of pre-formed transmucosal tissue to an implant level impression (Fig. 6c). Definitive prostheses were fabricated accordingly with custom abutments and ceramic crowns. The careful surgical planning and precision in execution resulted in the placement of implants at the desirable positions, which allowed us to fabricate screw-retained prostheses (Fig. 6d, e). To increase the strength and durability, the implant crowns of lateral incisor and canine were splinted on both sides. Patient was very satisfied with the esthetic outcome (Fig. 6f, g). Patient presented with continuous satisfaction with stable osseointegration in 3-year follow-up (Fig. 6 h, i).
