Multidisciplinary Approach to Patient-Specific Implants (PSIs): A Case Report and Review of Literature

Orthodontic treatment often faces challenges in achieving proper anchorage. While orthodontic mini-implants have gained popularity, no universally accepted design and insertion protocol exists for these implants. However, their relatively modest failure rate indicates their clinical reliability. To address complex geometries in the maxilla and mandible, patient-specific implants (PSIs) have emerged as a solution. PSI is currently employed in various domains of oral and maxillofacial surgery like temporomandibular joint (TMJ), total joint replacement, reconstruction of the facial skeleton, and orthognathic surgery. PSI allows for the creation of customized implant fits, leading to shorter rehabilitation times. This case report presents a multidisciplinary approach involving oral surgery and orthodontics, specifically focusing on the design of PSI, surgical placement of PSI, and use of PSI in maxillary protraction in orthodontics. The report highlights the design process of designing PSI and emphasizes its role in orthodontic treatment. By incorporating PSI as a temporary anchorage device (TAD), enhanced stability, precise control over tooth movement, and accurate repositioning of jaws can be achieved. The collaborative effort between orthodontists and oral surgeons is crucial in integrating PSI into the overall treatment plan. Despite the higher costs associated with PSI, their numerous advantages outweigh these drawbacks. PSI plays a vital role in providing enhanced stability, appropriate treatment plan, and achieving desired treatment in orthodontic and oral surgery procedures.


Introduction
Orthodontists face significant challenges when it comes to achieving proper anchorage during orthodontic treatment. To address this issue, orthodontic mini-implants have become widely utilized, despite the absence of a universally accepted design and insertion protocol. These mini-implants have shown a relatively modest reported failure rate of 13.5%, indicating their clinical reliability as orthodontic devices [1]. The introduction of mini-implants as temporary anchorage devices (TADs) has not only expanded the possibilities for tooth movement without the use of headgear but has also influenced the management of various orofacial deformities, malocclusions, and space problems prior to prosthetic replacement of missing teeth [2]. In recent years, mini-screws have emerged as an alternative to highly invasive techniques, serving as TADs for a range of orthodontic tooth movements, including forced eruption. Primary stability is considered a critical factor in assessing the success rate of these orthodontic devices.
Patient-specific implants have been introduced to address complex geometries found in the maxilla and mandible. PSI allows for the creation of customized implant that fits quickly and with greater accuracy, leading to shorter rehabilitation times and overall cost reduction. This technique involves extensive preoperative planning based on CT or MRI images, following the manufacturer's guidelines, and employing specialized software programs to manufacture disposable cutting blocks tailored to each patient's unique needs. Recent advancements in computer-aided design and computer-aided manufacturing (CAD/CAM) technology have facilitated the application of personalized medicine in oral and maxillofacial surgery, leading to improved outcomes. These developments have allowed for greater precision and customization in treatment planning and implementation. Furthermore, the decreasing cost of this technology has made it more affordable and accessible to patients [3]. In this case report, we present a multidisciplinary approach involving oral surgery and orthodontics which highlights our experience with PSI and their role in maxillary protraction in orthodontics. The report emphasizes the design process involved in creating PSI and the significant impact that PSI has had on orthodontic treatment. A 13-year-old female patient presented with a chief complaint of forwardly placed lower teeth. On examination, she had a concave profile and an anteriorly divergent face, and the patient had skeletal class III malocclusion attributable to a retrognathic upper jaw (Figure 1). To address this issue, bone-anchored maxillary protraction is planned with PSI.

FIGURE 1: Preoperative radiograph.
Depicts the preoperative radiograph showing Class III malocclusion. The arrow mark depicts the retrognathic maxilla in the lateral cephalogram.

Designing of patient-specific implant
The planning and manufacturing process of PSI involves several steps. Initially, cone-beam computed tomography (CBCT) was taken and the data from a CBCT scan was obtained in a DICOM file format. This was then transferred to Geomagic Software (3D Systems, NC, USA) for the fabrication of the patient-specific plates. This DICOM file is then converted into a stereolithographic (STL) format, which accurately represents the dimensions of the implant. The STL file is further converted into an SLI file format, which structures the implant into layered components, typically with a thickness of around 30 microns (Figure 2). The SLI file is subsequently sent to a 3D printer, where the implants were then three-dimensionally printed using selective laser melting with a 1.5-mm thickness of titanium metal using additive manufacturing techniques that create the implant layer by layer. Once the printing process is completed, the implant is removed from the printing platform and its supports. It undergoes polishing, wiping, and sterilization procedures to ensure cleanliness and sterility. Finally, the implant is packaged and delivered to the surgical team. Throughout this process, the orthodontist and surgeons helped design and approve the implant. Their expertise and involvement are essential in ensuring that the implant meets the specific requirements of the patient and the surgical procedure.

Surgical procedure
Under local anesthesia, a vestibular incision was placed in relation to the upper and lower premolars, and following that the mucoperiosteal flap was reflected. PSI were placed and secured with three titanium screws on each implant ( Figure 3). The closure was done with 3.0 polyglactin (3.0 Vicryl) (Figure 4). The hooks were exposed intraorally, where the elastics were placed postoperatively to achieve the desired orthodontic movement ( Figure 5).