A new technique to transfer the upper maxillary arch position using a facebow, a transfer table, and a reference block with a CAD application.

This paper presents a method for the digital transfer of the upper maxillary arch position using a facebow, a transfer table, and a reference block with a CAD application without requiring physical casts mounted with articulating gypsum. This technique facilitates the prosthetic digital workflow when the impression is made via intraoral scanning, to obtain the placement of the maxillary arch in the anatomical reference planes and in relation to the axes of rotation of the mandibular movements.

Research trends and perspectives on immediate facial reanimation in radical parotidectomy (Review).

For patients diagnosed with advanced malignant parotid tumour, radical parotidectomy with facial nerve sacrifice is part of the treatment. Multiple surgical techniques have been developed to cure facial paralysis in order to restore the function and aesthetics of the face. Despite the large number of publications over time on facial nerve reanimation, a consensus on the timing of the procedure or the donor graft selection has remained to be established. Therefore, the aim of the present study was to conduct a bibliometric analysis to identify and analyse scientific publications on the reconstruction of the facial nerve of patients who underwent radical parotidectomy with facial nerve sacrifice. The analysis on the topic was conducted using the built-in tool of the Scopus database and VOSviewer software. The first 100 most cited articles were separately reviewed to address the aim of the study. No consensus was found regarding the recommended surgical techniques for facial nerve reanimation. The most used donor cranial nerves for transfer included the following: Masseteric branch of the V nerve, contralateral VII nerve with cross-face graft, the XI nerve and the XII nerve. The best timing of surgery is also controversial depending on pre-exiting pathology and degree of nerve degeneration. However, most of the clinical experience suggests facial nerve restoration immediately after the ablative procedure to reduce complications and improve patients' quality of life.

Modular Digital and 3D-Printed Dental Models with Applicability in Dental Education.

Background and Objectives: The ever more complex modern dental education requires permanent adaptation to expanding medical knowledge and new advancements in digital technologies as well as intensification of interdisciplinary collaboration. Our study presents a newly developed computerized method allowing virtual case simulation on modular digital dental models and 3D-printing of the obtained digital models; additionally, undergraduate dental students' opinion on the advanced method is investigated in this paper. Materials and Methods: Based on the digitalization of didactic dental models, the proposed method generates modular digital dental models that can be easily converted into different types of partial edentulism scenarios, thus allowing the development of a digital library. Three-dimensionally printed simulated dental models can subsequently be manufactured based on the previously obtained digital models. The opinion of a group of undergraduate dental students (n = 205) on the proposed method was assessed via a questionnaire, administered as a Google form, sent via email. Results: The modular digital models allow students to perform repeated virtual simulations of any possible partial edentulism cases, to project 3D virtual treatment plans and to observe the subtle differences between diverse teeth preparations; the resulting 3D-printed models could be used in students' practical training. The proposed method received positive feedback from the undergraduate students. Conclusions: The advanced method is adequate for dental students' training, enabling the gradual design of modular digital dental models with partial edentulism, from simple to complex cases, and the hands-on training on corresponding 3D-printed dental models.

A novel experimental approach to evaluate guided bone regeneration (GBR) in the rat femur using a 3D-printed CAD/CAM zirconia space-maintaining barrier.

INTRODUCTION: Obtaining a certain bone volume is an important goal in implantology or orthopedics. Thus, after tooth extraction, quite a lot of horizontal and vertical alveolar bone is lost in time and can be detrimental to the implant treatment outcome, while the treatment of critical bone defects is a considerable challenge for surgery. OBJECTIVES: In this study we designed a new in vivo model as an useful experimental tool to assess guided bone regeneration (GBR) using a computer-aided design/manufacturing (CAD-CAM) space-maintaining barrier. METHODS: The barrier was 3D printed with three progressive heights, surgically placed on rat femur, and GBR results were analyzed at 2, 4, and 8 weeks by X-ray and bone mineral density analysis, histology/morphometry and by immunofluorescence and immunohistochemistry for osteogenesis and angiogenesis evaluation. RESULTS: The obtained results show that the proposed experimental model provides a real-time useful information on progressive bone tissue formation, which depends on the volume of isolated space created for GBR and on molecular events that lead to satisfactory vertical and horizontal bone augmentation and osteointegration. CONCLUSION: In conclusion, the proposed customized three-dome space-maintaining barrier is suitable as an experimental tool to assess the potential of using the designed barriers in dentistry and orthopedics to promote the formation of new bone and determine their space- and time-dependent limitations. Meanwhile, guided bone augmentation for dentistry requires subsequent evaluation on an alveolar bone preclinical model followed by clinical implementation.

Virtual facebow technique using standardized background images.

The procedure described provides a novel and accessible virtual facebow transfer based on standardized photographs loaded in the virtual articulator module of a computer-assisted design and computer-assisted manufacturing (CAD-CAM) software program for dental applications. The practical application of the technique in a digital workflow is the correct alignment of the digital maxillary cast to the virtual articulator with respect to the patient's planes and the skin markings of the condylar axis.

Osteotome-mediated sinus floor elevation: a systematic review and meta-analysis.

PURPOSE: The objectives of this study were to systematically review the literature regarding sinus floor elevation using osteotomes with respect to the timing of implant placement, implant characteristics, grafting materials, and intraoperative and postoperative complications and to perform a meta-analysis to determine the influence of initial residual bone height (RBH) on implant success. MATERIALS AND METHODS: A systematic search of articles was conducted on MEDLINE and manually to identify studies of sinus floor elevation using osteotomes. Strict inclusion criteria were applied. The mean observation period was ≥ 1 year after functional loading of implants. The quality of the included papers was assessed using the Newcastle-Ottawa Scale for observational studies and the PEDro Scale for randomized clinical trials, and the heterogeneity of the papers included in the meta-analysis was evaluated. The statistical accuracy was tested using the Cochran C test, and the relationship between initial RBH and implant success was analyzed using the Student t test Welch variant. RESULTS: Twenty-five studies published over a period of 13 years met the inclusion criteria; 15 were retrospective, 9 were prospective, and 1 was a randomized controlled trial. The included articles comprised 3,092 inserted implants with a failure rate of 3.85%. Of the 25 included studies, 8 were selected for the meta-analysis. RBH > 4 mm did not influence implant success/failure; however, there was a significant difference between the success/failure rates of implants, inserted in combination with sinus floor elevation using osteotomes, when the initial RBH was < 4 mm. CONCLUSION: Initial RBH of less than 4 mm influenced the success rates of implants inserted in combination with sinus floor elevation using osteotomes.