Augmented Reality Innovation in Prosthodontics and Smile Design

Prosthetic dentistry is one of the dental branches that has evolved remarkably over the last decades taking advantage of the digital innovations and technological advancements in diagnosis, treatment planning, computer-aided design/computer-aided manufacturing of prosthetic appliances, and delivery of advanced treatment. Augmented reality (AR) is an enhanced version of virtual reality created using digital technology to superimpose virtual and real objects in a single realistic environment on an operator’s view of the real world, hence creating a computer-generated working scenario to enhance the sensory perception by interacting with it [1].

AR technology consists of devices including displays that are either head-mounted, handheld, or spatial displays, input devices, tracking devices, and a computer. Recently, AR systems utilized contact lenses and virtual retina displays to show scanned images directly onto the viewer’s eyes’ retina. While tracking devices involved digital cameras and similar optical sensors, accelerometers, solid-state compasses, global positioning systems [GPS], and wireless sensors [2]. The superimposed virtual objects are usually obtained from 3-dimensional computed tomographic dental scans, MRI, angiography, or other 3-D data [3]. In dentistry, AR was initially used in education in contribution with haptic feedback that introduced the perception of force sensation. It was possible to have an immersive experience while learning in a virtual environment. AR enhanced education outcomes supported patient safety and objectively evaluated students, and gave them direct feedback [4]. The scope of indications of AR has expanded to incorporate radiology, orthodontic bracket positioning, prosthetics augmentation, management of dental phobia, endodontic surgery, and oral and maxillofacial surgery [2].

AR enabled the visualization of digital images and preoperative planning data to assist in accurately positioning of the dental implants and drilling on the correct spatial position. AR is especially significant regarding the oral and maxillofacial region, where the peculiar anatomical complexity of the region has always complicated the surgical position of dental implants [5]. Surgical navigation implicates knowing proper anatomical orientation and the prediction of implant position in bone before starting the incision. AR systems project the patient’s data and pictures as retrieved from computed tomography, MRI, anatomic models, and intraoperative pictures directly on the surgical site. AR has been shown to improve dental implant positioning when a graphically superimposed suggested position is used on the patient during implant placement [3]. AR implant surgical navigation was presented using retinal imaging rather than monitor display to avoid looking away from the oral surgical field during the operation. Furthermore, AR systems were improved to act as an automatic information filter that selectively displays only the surgeons’ most relevant information [1]

In prosthetic rehabilitation with dental implants, the focus of AR technology was to achieve a more visible surgical field during the operation, which was brought using specific glasses and an integrated screen. AR allowed the surgeon to visualize, in real-time, patient parameters, relevant x-rays, 3D reconstruction, or a navigation system screen [6].

Many studies have been done to illustrate the efficiency of AR in dental implant surgical planning. A study done by Lin., et al. used the stereoscopic visualization concept combined with head mounted AR displays, revealed that implant placement accuracy, as measured by the deviation between the planned and the prepared positions of the implants, significantly improved by combined integration of the surgical template and AR technology [7]. Jiang., et al. attempted placing dental implants in edentulous mandibular models using 3D AR-guided implant navigation. The postoperative results showed better accuracy, higher efficiency, and shorter time for the 3D AR navigation than the traditional 2D image navigation method [8]. The accuracy of dynamic implant navigation using AR HoloLens was presented by Pellegrino., et al. The position of the implants was virtually planned. It contributed to a dynamic navigation system in addition to a computer-aided/image-guided procedure. The HoloLens enabled the visualization of 2D/3D data and permitted device-control via voice commands or simple gestures, which helped the practitioner to visualize the system data, information, targets, and positions by placing a virtual desktop near the patient’s face without being forced to look away from the patient’s mouth. The study appraised AR as a valuable tool in reducing operation time and accurate implant positioning, although it recommended that specific software applications be further upgraded to optimize the results [6]. In another study, AR navigation with accurate CBCT-patient registration for dental implant placement demonstrated acceptable implant accuracy, intraoperative time, and resolution of the hand eye coordination problem [9].