## 3 Results
### Applications in Clinical Practice  
The medical applications of AR are currently concentrated on different surgery types, including neurosurgery, laparoscopic surgery, and plastic surgery. In dentistry, AR is primary used in oral and maxillofacial surgery, dental implant placement and orthognathic surgery [24]. The development of AR devices allows the user to combine the medical information, medical data, and images to the reality. In contrast to conventional image-guided \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline  & **PerioSim®** & **DenstimTM** & **IDEA** & **Simodon®** & **Voxel Man** & **CDS** \\ \hline
**Teeth Used** & Animated & Plastic teeth & Animated & Animated & Animated & Animated \\ \hline
**Right And Left** & & & & & & \\
**Operation** & Available & Available & Available & Available & Available & Available \\ \hline
**Reported Real** & & & & Tactile & & 3D images are & \\
**Life** & Tactile & Realistic & sensation still & & & the texture of & \\
**Expience** & sensation is & experience & needs to be & & healthy & \\
**Life** & realistic for & using plastic & tuned to & & decayed and & / & / \\
**Experience** & teeth but not for & & teeth on a real & simulate a & restored & \\  & gingiva & manikin & genuine & tooth structure still & & \\  & & & sensation & needs & & \\  & & & & improvement & & \\ \hline
**Ergonomic** & & & & & & \\
**Postures** & No & Yes & No & Yes & No & Yes \\ \hline
**Proced Transfer of** & & & & & & \\
**Data to Program** & & & & & & \\
**Instructor/Tutor** & & & & & & \\  & & & & & & \\  & & & & & & \\ \hline
**Instant Feed Back** & No & Yes & Yes & Yes & Yes & Yes \\ \hline
**Exam Simulation** & Yes & Yes & No & Yes & Yes & Yes \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Comparison of different dental simulators. surgery, where a surgeon often looks away from the operative field to view the informative data, AR guidance systems provide real-time intraoperative information directly on the surgical fields and this may decrease the surgical risk [25]. In dental implant placement, AR has been shown to substantially improve a wide range of procedures. A dental implant positioning system with a graphically superimposed suggested position on the patient was introduced as early as 1995. The AR surgical navigation systems for implant placement were introduced using retinal imaging display such that the surgeon maintains the view of the operative field without looking away [26]. During implant placement, AR can act as automatic information filters that selectively display only the most relevant information to surgeons, thereby helping them concentrate fully on the implant placement thereby reducing time and additional costs [27]. Orthognathic surgery is one of the most widely used fields of AR applications in dentistry. The most important advantage of AR-based navigation systems for orthognathic surgery is the possibility to provide overlaid images of real surgical views and virtual surgical plans for guidance. The systems overlay these models onto real-time streaming video images to provide surgeons with preoperative planning and anatomical information. Different AR-based systems were introduced for the simulation of the reduction of mandibular angle and the simulation of the mandibular reconstructive surgery [28; 29; 30]. Innovative systems were also developed to simulate mandibularotomy and fibular transplant to the mandibular defect site using 3D patient mesh models. In addition, it allowed surgeons to test and find configurations of vessels and skin paddles [31]. [PERSON] et al. used an AR-system to display overlaid images to allow surgeons to follow virtual surgical plans when repositioning patient bones after maxillofacial osteotomies [32]. Even VR was applied in orthognathic surgery in order to train different procedures of orthognathic maxillofacial surgery. To better simulate the surgical procedures the VR system can include and replicate different functions such as bone sawing, drilling, and place fixation with haptic force feedback [28; 33].