Evaluation of the different exposure parameters for the accurate diagnosis of peri-implantitis severity in digital panoramic radiography

To evaluate the accuracy of the diagnosis of peri-implant bone defects? severities in digital panoramic radiographs obtained at different tube voltage and/or tube current settings. Two different sizes of peri-implant bone defects (type 1 and type 2) were prepared after the implants were inserted into 29 bovine rib blocks. Digital panoramic radiographs were obtained at eight different tube voltage and/or tube current settings for all rib blocks. Implant images were cropped separately. The average intensity value (AIV) of cropped images were analyzed using Adobe Photoshop CC software. The Kruskal-Wallis H test was used to compare AIVs. All cropped images were evaluated using a five-point Likert scale for the likelihood of a bone defect being absent or present. The weighted kappa values were calculated to compare observer agreement and ROC analysis was performed to determine the appropriate exposure parameters. The lowest AIV was obtained at 72 kV/6.3 mA (92.162±16.016), and the highest AIV was obtained at 60 kV/3.2 mA (179.050±13.823). The Kruskal-Wallis H test showed significant differences in the AIVs according to the exposure parameters (p<0.001). The kappa coefficient for the inter-observer agreement was excellent (0.864, p<0.001). The AUC values for type 1 defects ranged from 0.778 and 0.860; for type 2 defects ranged from 0.920 and 0.967. The AUC value of type 1 defects was slightly better in panoramic images obtained with high kV and low mA levels (72 kV/3.2 mA), compared to others. In daily clinical routine, peri-implant bone defects might be evaluated by panoramic radiographs obtained with all kV and mA values tested. However, to avoid misdiagnosing and for better accuracy, panoramic radiographs obtained with high kV and low mA levels suiTable for patients should be used, especially in the detection of small or initial bone defects

Computer-assisted dental implant placement following free flap reconstruction: virtual planning, CAD/CAM templates, dynamic navigation and augmented reality

Image-guided surgery, prosthetic-based virtual planning, 3D printing, and CAD/CAM technology are changing head and neck ablative and reconstructive surgical oncology. Due to quality-of-life improvement, dental implant rehabilitation could be considered in every patient treated with curative intent. Accurate implant placement is mandatory for prosthesis long-term stability and success in oncologic patients. We present a prospective study, with a novel workflow, comprising 11 patients reconstructed with free flaps and 56 osseointegrated implants placed in bone flaps or remnant jaws (iliac crest, fibula, radial forearm, anterolateral thigh). Starting from CT data and jaw plaster model scanning, virtual dental prosthesis was designed. Then prosthetically driven dental implacement was also virtually planned and transferred to the patient by means of intraoperative infrared optical navigation (first four patients), and a combination of conventional static teeth supported 3D-printed acrylic guide stent, intraoperative dynamic navigation, and augmented reality for final intraoperative verification (last 7 patients). Coronal, apical, and angular deviation between virtual surgical planning and final guided intraoperative position was measured on each implant. There is a clear learning curve for surgeons when applying guided methods. Initial only-navigated cases achieved low accuracy but were comparable to non-guided freehand positioning due to jig registration instability. Subsequent dynamic navigation cases combining highly stable acrylic static guides as reference and registration markers result in the highest accuracy with a 1-1.5-mm deviation at the insertion point. Smartphone-based augmented reality visualization is a valuable tool for intraoperative visualization and final verification, although it is still a difficult technique for guiding surgery. A fixed screw-retained ideal dental prosthesis was achieved in every case as virtually planned. Implant placement, the final step in free flap oncological reconstruction, could be accurately planned and placed with image-guided surgery, 3D printing, and CAD/CAM technology. The learning curve could be overcome with preclinical laboratory training, but virtually designed and 3D-printed tracer registration stability is crucial for accurate and predictable results. Applying these concepts to our difficult oncologic patient subgroup with deep anatomic alterations ended in comparable results as those reported in non-oncologic patients.This work was supported by grant PI18/01625 (Ministerio de Ciencia e Innovación-Instituto de Salud Carlos III and European Regional Development Fund "Una manera de hacer Europa"). This study was also supported by Ticare® implants (Mozo-Grau, Valladolid, Spain). The funder was not involved in the study design, collection, analysis, interpretation of data, the writing of this article or the decision to submit it for publication

Cone-Beam Computed Tomography for Oral and Maxillofacial Imaging

The invention of computed tomography (CT) technique revolutionized diagnostic imaging. Compared to conventional X-ray imaging procedures, CT involves higher radiation doses. Recently, cone-beam CT (CBCT) specifically designed for maxillofacial imaging was introduced. CBCT technique is based on a cone-shaped X-ray beam centered on a two-dimensional (2D) detector. The detector system performs one rotation around the patient, producing a series of 2D images which are then reconstructed in a 3D data set. The contemporary knowledge regarding CBCT and its proper application guides the practitioner for improvement in diagnostic purposes and treatment planning. The aim of this chapter is to focus on the details, advantages, drawbacks, and clinical applications of CBCT as a headmost CT imaging technique in the oral and maxillofacial (OMF) region. The main clinical applications of CBCT in the OMF region are dentistry including dentoalveolar and maxillofacial surgery, orthodontics, endodontics, and periodontics; and otolaryngology. The aforementioned clinical use of CBCT was described in detail with illustrated sample cases. In most of the cases in OMF region, CBCT takes the place of multi-slice CT. Thus, clinicians should know the clinical applications and capabilities of CBCT technique with its drawbacks

Validation of an intra-oral scan method versus cone beam computed tomography superimposition to assess the accuracy between planned and achieved dental implants: a randomized in vitro study

Computer aided implantology is the safest way to perform dental implants. The research of high accuracy represents a daily effort. The validated method to assess the accuracy of placed dental implants is the superimposition of a pre-operative and a post-operative cone beam computed tomography (CBCT) with planned and placed implants. This procedure is accountable for a biologic cost for the patient. To investigate alternative procedure for accuracy assessment, fifteen resin casts were printed. For each model, six implants were digitally planned and then placed following three different approaches: (a) template guided free hand, (b) static computer aided implantology (SCAI), and (c) dynamic computer aided implantology (DCAI). The placement accuracy of each implant was performed via two methods: the CBCT comparison described above and a matching between implant positions recovered from the original surgical plan with those obtained with a post-operative intraoral scan (IOS). Statistically significant mean differences between guided groups (SCAI and DCAI) and the free hand group were found at all considered deviations, while no differences resulted between the SCAI and DCAI approaches. Moreover, no mean statistically significant differences were found between CBCT and IOS assessment, confirming the validity of this new method

The influence of L-PRF in socket healing with immediate implants: proposal of a prospective randomized split-mouth study design

Tese de mestrado, Medicina Dentária, Universidade de Lisboa, Faculdade de Medicina Dentária, 2018Introduction: Tooth extractions are one of the most common procedures in dentistry, leading to important changes in the edentulous ridge. These may not allow a satisfactory positioning of dental implants and they may compromise the result of the prosthetic rehabilitation. Immediate implants can be a viable treatment option, reducing the number of surgical procedures and the treatment period. However, one potential disadvantage is the gap formed between implant and buccal bone. To regenerate this bone defect, techniques have been developed that include the placement of different grafting materials such as xenografts and most recently, Leukocytes and Platelet-rich Fibrin (L-PRF). The aim of this prospective split-mouth study is to analyze the effectiveness of L-PRF regeneration in post-extraction sockets with immediate implant placement, compared to regeneration with xenograft biomaterial (Bio Oss®). Materials and Methods: Participants who fill the inclusion criteria will be part of both groups. Control and test site will be randomly assigned, at surgery day. At the surgery day, L-PRF membrane will be prepared and the implant will be placed in post-extraction socket. The gap will be filled with L-PRF membrane in test site and xenograft in control site. Clinical evaluation includes intra-oral photographs, healing tissue evaluation and keratinized soft tissue gain. Radiographic examination will consist in periapical radiographs and CBCT to measure bone marginal loss and bony defect regeneration. Follow-up appointments will be performed at day 10 and 30, 3 months, 6 months and 1 year after surgery. Participants will fill a questionnaire to self-assess post-operative pain. Finally, 1 year after surgery, implant’s survival and success will be assessed. Main Considerations: The literature indicates good results concerning L-PRF application. However, there is a limited number of studies and a lack of standardization, thus exposing the need for further RCTs assessing the effect of L-PRF on bone and soft tissue regeneration

Applications of aerospace technology in biology and medicine

Results of the medically related activities of the NASA Application Team Program at the Research Triangle Institute are reported. A survey of more than 300 major medical device manufacturers has been initiated for the purpose of determining their interest and opinions in regard to participating in the NASA Technology Utilization Program. Design and construction has been commissioned of a permanent exhibit of NASA Biomedical Application Team accomplishments for the aerospace building of the North Carolina Museum of Life and Science at Durham, North Carolina. The team has also initiated an expansion of its activities into the Northeastern United States

Assessment of 3D Facial Scan Integration in 3D Digital Workflow Using Radiographic Markers and Iterative Closest Point Algorithm

Introduction: Integration of 3 dimensional (3D) facial scanning into digital smile design workflows has been made available in multiple commercially available systems. Limited data exists on the accuracy of facial scans and accuracy of various methods of merging facial scans with cone beam computed tomography (CBCT) scans.Objective: The purpose of this prospective clinical study was to evaluate the accuracy of 2 methods used to integrate soft tissue facial scans with CBCT scans. It would allow proposal of a novel approach for integrating a 3D facial scan using facial radio-opaque markers in a 3D digital workflow.Material and methods: Fifteen CBCT and 3D face scans were obtained from patients who were undergoing treatment at MUSoD. A DICOM with RO markers and 3 STL data files from the facial scans were obtained for each patient. These files were superimposed using Exocad software. Accuracy of superimpositions was evaluated by measuring distances between RO markers on DICOM and STL data. The obtained dataset was analyzed using the paired t-test. Results: The results showed that the mean values for the 6 subsets, merging through the ICP algorithm, were 1.47-2mm. However, when merged by RO markers, the mean valuewas 0.14mm. Using a paired t-test, the novel RO points method was statistically more accurate than ICP algorithm method (