Augmented reality in orthodontics for bracket placement using conventional mobile devices: Technical note

BACKGROUND

Improving bracket placement accuracy through computer-aided design and a bracket navigation set supported by augmented reality (AR).

METHODS

A technical workflow was developed for implementing AR-assisted orthodontic bracket positioning through a smartphone application. This innovative approach eliminates the need for three-dimensional radiation imaging or physical guides, making it a safe and convenient option for clinical use by overlapping the digitally planned bracket position over the patient clinical crown for a precise recommendation of bracket positioning.

RESULTS

It was found that it is achievable and can be easily recognized from all view angles, and this proves that new techniques with new opportunities could be considered.

CONCLUSIONS

AR smartphone applications can potentially be used for the accurate placement of dental brackets; thus, such applications show promise for use in the field of orthodontics.

Virtual Surgical Planning in Head and Neck Reconstruction

Virtual surgical planning is a revolutionary tool for the head and neck reconstructive surgeon. As with any tool, there are strengths and weaknesses. The strengths include shorter operative time, shorter ischemic time, streamlined dental rehabilitation, facilitation of complex reconstruction, non-inferior and possibly superior accuracy, and increased durability. The weaknesses are increased up-front costs, potential delays to operative management, limited flexibility on the day of surgery, and loss of familiarity with conventionally planned surgery.

Design and Simulation of an Autonomous Molecular Mechanism Using Spatially Localized DNA Computation

As a well-established technique, DNA synthesis offers interesting possibilities for designing multifunctional nanodevices. The micro-processing system of modern semiconductor circuits is dependent on strategies organized on silicon chips to achieve the speedy transmission of substances or information. Similarly, spatially localized structures allow for fixed DNA molecules in close proximity to each other during the synthesis of molecular circuits, thus providing a different strategy that of opening up a remarkable new area of inquiry for researchers. Herein, the Visual DSD (DNA strand displacement) modeling language was used to design and analyze the spatially organized DNA reaction network. The execution rules depend on the hybridization reaction caused by directional complementary nucleotide sequences. A series of DNA strand displacement calculations were organized on the locally coded travel track, and autonomous movement and addressing operations are gradually realized. The DNA nanodevice operates in this manner follows the embedded "molecular program", which improves the reusability and scalability of the same sequence domain in different contexts. Through the communication between various building blocks, the DNA device-carrying the target molecule moves in a controlled manner along the programmed track. In this way, a variety of molecular functional group transport and specific partition storage can be realized. The simulation results of the visual DSD tool provide qualitative and quantitative proof for the operation of the system.

Customized guide for transmucosal pterygomaxillary disjunction: Proof of concept

Potential complications related to pterygomaxillary disjunction have been widely described in the literature, most of them being due to the inaccurate and blind approach involved. The present study used preoperative virtual planning to establish a surgical cutting guide for pterygomaxillary osteotomy. It was placed in the maxillary tuberosity supported by molars, and a flapless vertical osteotomy was performed with a piezoelectric saw. Then, maxillary down-fracture was performed with slight pressure through an anterior approach. The use of the surgical guide added accuracy and predictability to the procedure, with no prolongation of the surgery time. There were no undesired fractures or bleeding. Regarding manipulation of the surgical guide in the posterior area, it was found to be easily manageable and very stable over the posterior teeth, due to its small size and precision, respectively. In conclusion, this technique seems to improve the accuracy of pterygomaxillary disjunction without prolonging the surgery time. Furthermore, it reduces potential complications related to the conventional procedure. Nevertheless, a larger body of patient data is needed to confirm the benefits of the technique.

Utilizing virtual surgical planning and orthognathic surgery to correct severe facial asymmetry without orthodontic treatment

Combining double-jaw surgery and orthodontic treatment to correct dentofacial asymmetry is a standard procedure but time consuming and costly. In order to provide alternative solutions, previewing the possible results with precise virtual surgical planning (VSP) system can help clinicians select patients suited for correcting facial asymmetry surgically without orthodontic treatment. In our experiences, after rigid or semirigid fixation of the maxilla, using intermaxillary fixation (IMF) without mandibular bony fixation is another key. This kind of fixation can minimize the chances of changing the condylar position and occlusion after the rotation of the maxillomandibular complex. If the original occlusion can be maintained, then orthodontic treatment can be avoided. Here we presented two facial asymmetry cases who requested surgical correction and refused orthodontic treatment. With careful preoperative planning using VSP, double-jaw surgery with maxillary bony fixation and IMF was conducted and both patients were satisfied by their aesthetic outcomes. With minimal dental compensation, the long-term results were relatively stable.

Facial Contour Refining after Surgery-First SSRO with Computer-Assisted Design in East Asians

BACKGROUND

Surgery-first sagittal split ramus osteotomies (SF-SSRO) are an effective treatment for patients with dental malocclusion. However, some patients with mandibular prognathism usually have facial deficiencies which cannot be corrected completely after orthognathic surgery. These are not accepted because the remaining facial contours are in disharmony.

METHODS

Twenty-five patients, who were unsatisfied with their appearances after SF-SSRO and orthodontics, were included. The preoperative CTs were used to investigate patients for facial deformity. To achieve a harmonious facial contour, mandible long-curve osteotomy/mandible U-shaped osteotomy, genioplasty or facial autologous fat grafting was selected depending on patients' contour deformities with the assistance of CAD.

RESULTS

Among the patients who underwent osteotomy, the gonial angle was improved from 111.16° ± 9 to 111.58° ± 9.06 after SF-SSRO because of distal fragment setback and rotation. After facial refine surgery, the gonial angle was significantly increased to 121.69°±2.41 (p < 0.05). And the mandibular width was decreased from 11.29 cm ± 0.44 to 10.45 cm ± 0.39 (p < 0.05) after mandibular outer plate griding. All patients were shown no signs of infection, massive bleeding, and osteonecrosis in the early stage. After follow-up time, they were all satisfied with their results and most of them recovered from lip numbness.

CONCLUSIONS

This study indicated the clinical feasibility of two-stage orthognathic and facial bone contouring surgery for the treatment of dentofacial deformities. Two-stage facial contouring surgery can provide esthetic improvement for more accuracy in refining the facial contour.

LEVEL OF EVIDENCE IV

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Using Cranial Sutures in a Single-Step Frame-Guided Resection and Reconstruction for Intraosseous Meningiomas: Technical Note

BACKGROUND

Single-stage surgical treatment of cranial intraosseous meningiomas includes complete tumor resection followed by aesthetic reconstruction. Tailored tumor resection with a computer-aided design/computer-aided manufacturing custom-made implant for the defect has been advocated in recent years to achieve a satisfactory cosmetic result with reduced operative time and fewer complications. However, several technical nuances related to the area of osseous removal may compromise cranioplasty.

METHODS

We present 2 cases of intraosseous meningiomas (sphenoid wing and retromastoid) to illustrate a step-by-step approach, from preoperative planning to single-step surgery.

RESULTS

For each case, a customized frame template delimiting bone removal was designed using cranial sutures as anatomical landmarks for precise placement of the cranioplasty template over the area of interest.

CONCLUSIONS

Custom templates based in cranial sutures may benefit single-step frame-guided resection and reconstruction of intraosseous tumors with compelling results.

Computer-assisted mandibular curved osteotomy: An automatic method to design the new aesthetic gonion and osteotomy line

BACKGROUND

Digital technology has been widely used in mandibular curved osteotomy to improve accuracy. However, the planning process still highly dependent on the experience and judgement of the surgeon. This study describes an automatic method to design the new gonion and osteotomy line based on the aesthetic standards in attractive women, and assesses its clinical outcomes.

METHODS

An automatic surgical planning method for mandibular curved osteotomy was developed based on our previous research of mandibular angle aesthetics. A prospective clinical study was conducted from April 2016 to April 2018. Twenty-five female patients with prominent mandibular angle were enrolled. Pre- and postoperative skull computed tomography (CT) was performed. Three-dimensional (3D) CT data were obtained and processed by Mimics 18.0. Surgical templates were designed according to the automatic surgical planning method and 3D printed for the surgery. Preoperative measurements, surgical simulation and postoperative measurements were taken to evaluate the surgical outcomes.

RESULTS

There were significant differences between the preoperative and the postoperative groups' results (p < 0.01). There was no difference between the surgical simulation and the postoperative results. All postoperative measurements were consistent with aesthetic features of mandibles. Patients were satisfied with their outcomes in terms of outline, symmetry and lower facial width.

CONCLUSIONS

Our study developed an automatic method to position the new aesthetic gonion and osteotomy line for prominent mandibular angle patients. We proved that this method is safe, effective and reliable.

Integration of 3D printing and additive manufacturing in the interventional pulmonologist's toolbox

New 3D technologies are rapidly entering into the surgical landscape, including in interventional pulmonology. The transition of 2D restricted data into a physical model of pathological airways by three-dimensional printing (3DP) allows rapid prototyping and fabrication of complex and patient-specific shapes and can thus help the physician to plan and guide complex procedures. Furthermore, computer-assisted designed (CAD) patient-specific devices have already helped surgeons overcome several therapeutic impasses and are likely to rapidly cover a wider range of situations. We report herein with a special focus on our clinical experience: i) how additive manufacturing is progressively integrated into the management of complex central airways diseases; ii) the appealing future directions of these new technologies, including the potential of the emerging technique of bioprinting; iii) the main pitfalls that could delay its introduction into routine care.