Reliability of a Virtual Prosthodontic Project Realized through a 2D and 3D Photographic Acquisition: An Experimental Study on the Accuracy of Different Digital Systems

Advancements in Diagnostic Methods and Imaging Technologies in Dentistry: A Literature Review of Emerging Approaches

Introduction: Recent advancements in diagnostic imaging technologies have significantly improved the field of dental medicine. This review examines these new imaging techniques and their impact on enhancing accuracy, enabling early detection, and facilitating effective treatment planning in dentistry. Methods: A bibliometric and content analysis was conducted on 61 peer-reviewed articles retrieved from the Scopus database, published between 2019 and 2024. The selection criteria focused on studies exploring advances in dental diagnosis through innovative imaging methods and personalized techniques for identifying oral pathologies. The bibliometric approach analyzed publication trends, while content analysis categorized emerging technologies and their clinical applications. Results: Our findings indicate a notable shift towards integrating cutting-edge technologies, including Cone Beam Computed Tomography (CBCT), artificial intelligence (AI), and biosensors. These advancements have significantly improved diagnostic accuracy, particularly in complex cases such as periodontal diseases, dental fractures, and oral infections. Studies demonstrate that molecular diagnostics and AI-driven algorithms enhance the personalization of treatment plans, optimizing patient outcomes. Conclusions: Emerging diagnostic technologies have the potential to enhance both the quality and efficiency of dental care. However, their implementation is challenged by high costs, the need for specialized training, and disparities in access. Future research should focus on refining AI-driven diagnostic models, addressing regulatory considerations, and expanding the clinical validation of novel imaging tools. As these technologies evolve, they are expected to increase diagnostic specificity, leading to more precise, patient-centered treatment approaches. Ultimately, these advancements offer substantial opportunities to transform dental practice by providing faster, less invasive, and more reliable diagnoses.

Clinical use of digital applications for diagnostic and treatment planning in prosthodontics: A scoping review

AIM

This scoping review aimed to compile and evaluate clinical trials investigating digital applications in prosthetic diagnostics and treatment planning by assessing their clinical relevance and future potential.

METHODS

Following the PCC-framework for scoping reviews and combining the source of analysis (Population/P: "prosthodontics"), the technique of interest (Concept/C: "digital application") and the field of interest (Context/C: "diagnostics"), a three-pronged search strategy was applied in the database PubMed and Web of Science. Clinical trials (≥10 study participants, English/German) were considered until 2023-03-09. Reporting adhered to the PRISMA-ScR statement.

RESULTS

The search identified 520 titles, of which 18 full-texts met the inclusion criteria for data extraction. The trials involved a total of 14,457 study participants and were mapped for prosthetic subdisciplines: fixed (n = 9; 50%) and removable (n = 4; 22%) prosthodontics, reconstructive dentistry in general (n = 3; 17%), and temporo-mandibular joint disorders (n = 2; 11%). Data merging of medical format files, as DICOM+STL, was the dominant digital application (n = 7; 39%); and virtual treatment simulation using digital smile design or digital wax-up represented the most frequent prosthetic diagnostics (n = 6; 33%).

CONCLUSION

This scoping review identified a relatively low number of clinical trials. The future potential of digital diagnostics appears to be mostly related to the subdiscipline of fixed prosthodontics, especially regarding virtual treatment simulation for communication with the patient and among dental professionals. Artificial intelligence emerged as a key technology in many of the identified studies. Further research in this area is needed to explore the capabilities of digital technologies in prosthetic diagnostics and treatment planning.

The Recent Use, Patient Satisfaction, and Advancement in Digital Smile Designing: A Systematic Review

Digital smile designing (DSD) is a concept of dentistry which combines the old and the new and becomes a different world in the world of smile aesthetics and functionality. Dental aesthetics is not just a cosmetic issue but a multidimensional part of oral health that has a great impact on psychological well-being, social life, functional capabilities, and, hence, the quality of life. To put it simply, the recognition of its significance stresses the necessity of complete dental care which is the one that combines beauty and function as well as health. This systematic review aims to analyze the recent use and patient satisfaction of DSD and to show the recent advances in DSD. A thorough literature search was conducted across the online databases for articles about the implementation of digital smile analysis in dentistry. The articles that were published between 2013 and 2023 on DSD were selected which included randomized and non-randomized trials and observational studies covering the effectiveness, advantages, and patients' opinions about the treatment. The National Institutes of Health tool was applied for bias assessment. Ten studies were selected to address the use of DSD in dentistry based on the inclusion criteria. The findings from these studies suggest that DSD is useful in improving communication, reducing working time, minimizing errors, enhancing patient satisfaction, and providing clinical adequacy for final prosthetic pieces, indicating the usefulness of this approach in dental procedures. Smile designing using digital technologies has the potential to improve dental aesthetics and treatment procedures while showcasing their reliability and clinical effectiveness.

Customized Facial Orthopedics: Proof of Concept for Generating 3D-Printed Extra-Oral Appliance for Early Intervention in Class III Malocclusion

Background: The present case report serves as a proof of concept for the fabrication and effective clinical administration of a 3D-printed chin cup tailored to the patient’s anatomical characteristics. Methods: An 11-year-old male with a Class III malocclusion was treated using a chin cup appliance to intercept and control a Class III mandibular skeletal growing pattern early. Two tailored chin cup devices were designed using 3D face scanning and CBCT scanning and were produced with additive manufacturing techniques. The chin pads were digitally designed based on a 3D scan of the patient’s face. The 3D modeling of chin cup components was performed using 3Shape Appliance Designer and 3D printed with biocompatible resin. An analogic chin pad was also produced for the same patient. The treatment plan involved the patient wearing the chin cup for 13 h per day. The patient was instructed to use all three chin pads produced at intervals of 4 months. The patient’s experience was assessed by reporting the comfort experience via a VAS scale. The treatment strategy was effective in improving the skeletal Class III malocclusion. Additionally, the integration of 3D face scanning (or CBCT scanning), modeling, and printing enables the production of customized chin cups with superior fit and comfort, contributing to enhanced patient compliance and treatment efficacy.

Analysis of implant precision in guided surgery: comparison of two methods

BACKGROUND

Implantology represents the therapy of choice for the rehabilitation of a partially or totally edentulous jaw in a healthy patient. Nowadays, it is possible to exploit of modern preoperative planning software, increasingly precise radiographic examinations (CBCT) and CAD/CAM technologies that allow designing devices directly on the computer to be sent to a milling center which produces the desired product, such as stereolithographic templates.

METHODS

The prospective clinical study in question aims to evaluate the accuracy between two different surgical guides using peek and metal guide bushings. Twenty-nine implants were placed: for the control group, 17 3i, T3 implants were used, while for the test group, 12 Xive S plus implants were used.

RESULTS

The result obtained shows that the deviations in the distribution of the control group and the test group are the same in the apical-coronal, vestibulo-palatal and mesio-distal direction. For the control group, the mean deviation was 1.394±0.644923 at the entry point of the implants and 1.85655±1.0765 at the most apical point of the implants. For the test group the mean deviation was 1.10157±0.312721 at the entry point of the implants and 1.54514±0.572100 at the most apical point of the implants.

CONCLUSIONS

The peek guide bushings have the same deviation as the metal ones. There is no difference in the method used, but precision must be sought in other elements, such as the patient's anatomy and maximum precision in the guide production phase.

The short- and long-term changes of upper airway and alar in nongrowing patients treated with Mini-Implant Assisted Rapid Palatal Expansion (MARPE): a systematic review and meta-analysis

OBJECTIVE

This study aims to assess the short- and long-term changes in the upper airway and alar width after mini-implant -assisted rapid palatal expansion (MARPE) in nongrowing patients.

METHODS

Five electronic databases (PubMed, Scopus, Embase, Web of Science, and Cochrane Library) were searched up to 2 August, 2023 based on the PICOS principles. The main outcomes were classified into three groups: 1) nasal cavity changes, 2) upper airway changes and 3) alar changes. The mean difference (MD) and 95% confidence intervals (CI) were used to assess these changes. Heterogeneity tests, subgroup analyses, sensitivity analyses, and publication bias were also analyzed.

RESULT

Overall, 22 articles were included for data analysis. Nasal cavity width (WMD: 2.05 mm; 95% CI: 1.10, 3.00) and nasal floor width (WMD: 2.13 mm; 95% CI: 1.16, 3.11) increased significantly. While palatopharyngeal volume (WMD: 0.29 cm3, 95% CI: -0.44, 1.01), glossopharyngeal volume (WMD: 0.30 cm3, 95% CI: -0.29, 0.89) and hypopharyngeal volume (WMD: -0.90 cm3; 95% CI: -1.86, 0.06) remained unchanged, nasal cavity volume (WMD: 1.24 cm3, 95% CI: 0.68, 1.81), nasopharyngeal volume (MD: 0.75 cm3, 95% CI: 0.44, 1.06), oropharyngeal volume (WMD: 0.61 cm3, 95% CI: 0.35, 0.87), and total volume of the upper airway (WMD: 1.67 cm3, 95% CI: 0.68, 2.66) increased significantly. Alar width (WMD: 1.47 mm; 95% CI: 0.40, 2.55) and alar base width (WMD: 1.54 mm; 95% CI: 1.21, 1.87) also increased.

CONCLUSION

MARPE can increase nasal cavity width, nasal cavity volume, nasopharyngeal volume and oropharyngeal volume for nongrowing patients, but has no significant effect on hypopharyngeal volume. In addition, the alar width also increased. However, the studies included in this meta-analysis were mainly retrospective, nonrandomized and small in number, so the findings should be interpreted with caution and high-quality RCTs need to be studied.

Photogrammetry technology in implant dentistry: A systematic review

STATEMENT OF PROBLEM

Photogrammetry technology may be useful in implant dentistry, but a systematic review is lacking and is indicated before routine use in clinical practice.

PURPOSE

The purpose of this systematic review was to assess the role of the photogrammetry technology used in implant dentistry and determine its validity as an accurate tool with clinical applications.

MATERIAL AND METHODS

Four major databases, PubMed MEDLINE, Google Scholar, Scopus, and Web of Science, were selected to retrieve articles published from January 2011 to February 2021 based on custom criteria. The search was augmented by a manual search. After screening of the collected articles, data, including study design and setting, type of application, digitizer used, reference body, method of evaluation, and overall outcomes, were extracted.

RESULTS

Twenty articles were included based on the selection criteria. Most of the articles confirmed that the use of photogrammetry was promising as an implant coordinate transfer system. However, few articles showed its use for 3-dimensional scanning, which might require more development.

CONCLUSIONS

The initial reports of using photogrammetry technology considered this method as a valid and reliable clinical tool in implant dentistry. More studies to develop the photogrammetry technology and to assess the results with evidence-based research are recommended to enhance its application in different clinical situations.

Influence of Torque on Platform Deformity of the Tri-Channel Implant: Two- and Three-Dimensional Analysis Using Micro-Computed Tomography

Background and Objectives: The insertion of the dental implant in the bone is an essential step in prosthetic rehabilitation. The insertion torque has the potential to distort the prosthetic platform, which can cause future biomechanical problems with the continuous action of occlusal forces. The aim of this study is to evaluate different insertion torques in the deformation of tri-channel platform connections through two- and three-dimensional measurements with micro-CT. Materials and Methods: A total of 164 implants were divided into groups (platform diameter and type): 3.5, 3.75, and 4.3 mm NP (narrow platform), and 4.3 mm RP (regular platform). Each implant-platform group was then divided into four subgroups (n = 10) with different torques: T45 (45 Ncm), T80 (80 Ncm), T120 (120 Ncm), and T150 (150 Ncm). The implant-abutment-screw assemblies were scanned and the images obtained were analyzed. Results: A significant difference was observed for the linear and volume measures between the different platforms (p < 0.01) and the different implant insertion torques (p < 0.01). Qualitative analysis suggested a higher deformation resistance for the 3.75 NP compared to the 3.5 NP, and RP was more resistant compared to the NP. Conclusions: The 0.25 mm increment in the implant platform did not increase the resistance to the applied insertion torques; the 4.3 mm implant was significantly stronger compared to the 3.5 mm implant; and the proposed micro-CT analysis was considered valid for both the 2D and 3D analyses of micro-gaps, qualitatively and quantitatively.

The application of a fully digital approach in the treatment of skeletal class III malocclusion: a preliminary study

BACKGROUND

Skeletal malocclusion patients have facial malformations and occlusal dysfunctions that require orthodontic-orthognathic joint treatment, while the combination treatment takes time and requires close communication between surgeons and orthodontists. Thus, improving the efficiency and effectiveness of the combination treatment is necessary, and it is still a challenge. Now, digital technology provides us with an excellent alternative. Despite the widespread use of digital technology in orthognathic surgery simulation and clear aligner orthodontic therapy, it has not been fully integrated into the combined orthognathic and orthodontic treatment process, and the components remain independent.

METHODS

A fully digital approach to seamlessly integrating various parts of the combined treatment through digital technology was investigated in this study in order to achieve an efficient transition. Five patients with skeletal Class III malocclusion were enrolled, and all made fully digital treatment plans at the beginning of actual implementation, which included the design of pre-surgical orthodontic, orthognathic surgery, and post-surgical orthodontic. Then, every aspect of the clinical operation was carried out in accordance with the fully digital routine. After the entire treatment process was completed, the skeleton and dentition discrepancy between virtual planning and the actual result was evaluated.

RESULTS

All participants completed the fully digital treatment process, and no complication was observed. The linear deviation of the skeletal anatomy was less than 1 mm, and the angular deviation was less than 1 degree. Except in one case in the lower dentition, the deviation of the virtual dental design from the real alignment was less than 2 mm. Furthermore, with one exception of maxillary anterior-posterior dimension, the linear deviations of the skeleton were not statistically significant. Therefore, the simulation accuracy of the fully digital approach was clinically acceptable.

CONCLUSIONS

The digital treatment approach is clinically feasible and has achieved satisfactory results. The discrepancy between virtual design of the entire digital process and actual post-treatment situation was acceptable in clinic. A fully digital approach was proved effective in the treatment of skeletal Class III malocclusion, with which the efficient transition of treatment procedures was realized.

Accuracy of virtual surgical planning in mandibular reconstruction: application of a standard and reliable postoperative evaluation methodology

OBJECTIVE

The purpose of this study was to determine the accuracy of virtual surgical planning for mandibular reconstruction, along with the implementation of a postoperative evaluation methodology.

MATERIALS AND METHODS

The study is a prospective case series for computer-assisted mandibular reconstruction surgery. Analysis of the degree of agreement between virtual measurements and postoperative actual outcomes was performed. The reliability of the proposed evaluation methodology was assessed and analyzed using the Inter-Class Coefficient (ICC) test. Statistical significance was set at the 5% level.

RESULTS

Nine consecutive patients were selected. The analysis of all angular and linear parameters reported a highly statistically significant degree of agreement between the preoperative and postoperative measurements (P < 0.001). Furthermore, an extreme degree of reliability was reported when the evaluation methodology was scrutinized (ICC = 0.9).

CONCLUSION

The excellent degree of agreement between the virtual plan and the actual outcome reported in this study validated the surgical accuracy of virtually assisted mandibular reconstruction. This study pointed out the reliability and reproducibility of the standardized evaluation protocol in an attempt to obtain a tolerable value for the acceptable postoperative results regarding the accuracy of computer-assisted surgery.

3D Printing of Dental Prostheses: Current and Emerging Applications

Revolutionary fabrication technologies such as three-dimensional (3D) printing to develop dental structures are expected to replace traditional methods due to their ability to establish constructs with the required mechanical properties and detailed structures. Three-dimensional printing, as an additive manufacturing approach, has the potential to rapidly fabricate complex dental prostheses by employing a bottom-up strategy in a layer-by-layer fashion. This new technology allows dentists to extend their degree of freedom in selecting, creating, and performing the required treatments. Three-dimensional printing has been narrowly employed in the fabrication of various kinds of prostheses and implants. There is still an on-demand production procedure that offers a reasonable method with superior efficiency to engineer multifaceted dental constructs. This review article aims to cover the most recent applications of 3D printing techniques in the manufacturing of dental prosthetics. More specifically, after describing various 3D printing techniques and their advantages/disadvantages, the applications of 3D printing in dental prostheses are elaborated in various examples in the literature. Different 3D printing techniques have the capability to use different materials, including thermoplastic polymers, ceramics, and metals with distinctive suitability for dental applications, which are discussed in this article. The relevant limitations and challenges that currently limit the efficacy of 3D printing in this field are also reviewed. This review article has employed five major scientific databases, including Google Scholar, PubMed, ScienceDirect, Web of Science, and Scopus, with appropriate keywords to find the most relevant literature in the subject of dental prostheses 3D printing.

Submodelling approach to screw-to-bone interaction in additively manufactured subperiosteal implant structures

Thanks to new digital technologies, complex cases of severe maxillary atrophy may now be treated with additively manufactured subperiosteal implant structures (AMSISs). However, there are few studies addressing this topic and most of them focus on the mechanical behaviour of the AMSIS itself without considering its interaction with the maxilla bone. The aim of this study is to provide a methodology based on finite element analysis (FEA) to evaluate the effect of interaction between the maxilla bone and the screws fixing the AMSIS. The mechanical performance of an AMSIS was examined via a FEA based on submodelling. Significant differences were encountered in displacements and reaction forces when bone-screw interaction was considered. Stress in the cortical layer was found to be close to the maximum strength while the trabecular layer seems to have no effect on the results; stresses in the AMSIS are lower than the fatigue stress limit. Finally, the comparison of stresses between models with and without osseointegration shows how stresses drop once osseointegration is complete. The proposed submodelling approach considerably reduces the computational effort and enables both a detailed model of the interaction between the thread of the screws and the bone and an accurate evaluation of displacement and stress fields on the interface. The results have shown that stresses in the cortical bone are highly affected by the initial geometry of the thread inside the bone, which demonstrates the importance of modelling the effect of the thread.

Finite Element Analysis of Zirconia Dental Implant

Titanium dental implants have had new competitors in recent years, such as fixtures made of zirconia, which promise better aesthetics. The purpose of this study is to evaluate their mechanical performance in silico (Finite Element Analysis). The investigation was performed on a single tooth Patent™ Dental Implant (Zircon Medical®, Altendorf, Switzerland) in two configurations: without offset (Test I) and with offset (Test II, 1.5 mm within the cortical bone). The Patent Implant system consists of two components: the implant with integrated abutment and the fibreglass post. The components of the dental implants were tested using a compression load of 400 N along the implant axis. The results showed that the chewing load generates stress distribution on the bone, therefore, the offset configuration should be avoided.

A comparison of accuracy between three different facial detection systems for prosthodontic esthetic preview: a single-blinded in vitro study

BACKGROUND

The aim of this study was to compare the accuracy of 3 different devices for facial images acquisition, useful for prosthodontic esthetic preview.

METHODS

Bidimensional extraoral photographs (Nikon D300), facial scans (Bellus3D) and 3D digital stereophotogrammetry photos (3dMD Face System) were acquired from 15 patients. The intraoral impressions of all subjects were digitally taken through a scanner (i500; Medit). Files obtained from each acquisition method were transferred on Exocad Software, and the measurements of the frontal teeth were performed and compared with those of the intraoral scans, assumed as reference. The data were statistically analyzed (Friedman and Dunn tests) with P<0.05.

RESULTS

As for central and lateral incisors, no significant difference emerged between 2D digital photography and intraoral scans, both in height and width. Measures obtained with Bellus3D significantly differed from the reference data in width of all teeth, except for central incisors. Values referred to canines were those more subjected to significant distortions in width for all devices.

CONCLUSIONS

Within the limits of this study, measures of frontal teeth acquired by 2D digital photography were similar to those of intraoral scans both in height and width, while those obtained with 3D facial scanners were more subjected to distortions in mesial-distal dimension.

Digital planning of composite customized veneers using Digital Smile Design: Evaluation of its accuracy and manufacturing

OBJECTIVES

This study aimed to evaluate the production of customized composite veneers starting from a two-dimensional (2D) digital preview using the Digital Smile System (DSS). MATERIAL AND METHODS: A photographic examination of 30 patients was performed by taking two digital pictures of the face and a digital preview through the DSS. Moreover, optical scans of the dental arches were obtained and the data were entered into a three-dimensional (3D) software to prepare a virtual preview. The standard tessellation language files were sent for production using CAD-CAM technology. The Friedman test, Bonferroni, and Dunn post hoc tests were used, comparing the linear measurements of the 2D and 3D plans and the final veneers (α = .05).

RESULTS

Significant differences emerged between the pictures and digital scans on the mesial-distal widths of the lateral incisors and canine. Linear measurements in the 2D plan were significantly different from those of the 3D plan, except for the height measures of incisors. No significant changes were found on comparing the parameters of the 2D and 3D plans with those of the final pieces.

CONCLUSIONS

The customized veneers were clinically adequate and similar to 2D and 3D plans, although significant differences emerged between the picture and digital scans as well as between the 2D and 3D plans.

Reliability of Anterior Nasal Spine as a Reference Point After LeFort I Surgery Using Three-Dimensional Analysis

ABSTRACT

To evaluate the stability of maxilla following orthognathic surgery, it is necessary to consider the positional change of various landmarks according to bone remodeling of the maxilla. This study aimed to evaluate the stability of the anterior nasal spine (ANS) as a reliable landmark after orthognathic surgery. Forty-seven patients with skeletal class III malocclusion who underwent bimaxillary orthognathic surgery were included. Skeletal changes were measured using cone-beam computerized tomography at 3 time points: preoperative (T0), 1-month postoperative (T1), and 12-month postoperative (T2). Linear changes of the 6 landmark points of the maxilla were measured in 3 directions: anteroposterior, vertical, and transverse. The data were analyzed with paired t tests, independent t tests, and multiple regression analysis. At 12-month postoperatively, the ANS showed mean (standard deviation) 1.23 (1.07) mm posterior movement (P = 0.00), while other landmarks did not show positional changes, implying bony resorption of ANS. Multiple regression test showed surgical forward movements of ANS (T1-0) affect the postoperative backward changes (β = -.05, P < 0.05). There was a negative correlation between the surgical movement and postoperative change of ANS by Pearson correlation test (r = -0.38, P < 0.05). The ANS is not a reliable measurement point in three-dimensional superimposition after orthognathic surgery. Therefore, in studying the stability and positional change pattern after LeFort I surgery, it is not recommended to use ANS as a reference point, as changes can occur in the measurement point itself.

Effect of a digital guide on the positional accuracy of intermaxillary fixation screw implantation in orthognathic surgery

BACKGROUND

Intermaxillary fixation screw (IMFS) implantation is a common procedure in orthognathic surgery (OGS) performed to the temporary maxillary-mandibular fixation and stable bite relationships. The study aims to assess the accuracy of IMFS implantation with a digital guide to reduce the occurrence of root damage.

METHODS

This prospective study involved 40 patients undergoing OGS at the Affiliated Hospital of Qingdao University from August 2017 to May 2021. The patients were randomly divided into two groups according to whether the IMFS implantation was with or without digital guide (20 patients in the experimental group and 20 controls). The digital guides used in the experimental group were designed according to a virtual implantation plan and printed using stereolithography. In the control group, IMFSs were directly implanted by a surgeon based on clinical experience. Postoperatively, cone-beam computed tomography was performed to compare root proximity of IMFSs between the two groups and verify the accuracy of IMFS placement.

RESULTS

In the experimental group, there was no case of root damage, the incidence of the periodontal ligament (PDL) injured was 22.1%, and 77.9% IMFSs were placed without contacting adjacent anatomic structures. In the control group, the incidence of root damage had been up to 20.8%, 31.7% IMFSs injured the PDL, and only 47.5% IMFSs were placed between the roots (P < 0.001).

CONCLUSION

IMFSs can be placed more accurately with surgical guides, reducing the incidence of root and PDL damages.

A Rare Case of Front Mandible Orthokeratinized Odontogenic Cyst - Surgical Management with Preventive Rigid Osteosynthesis

PURPOSE

Cysts and other intrabony lesions can grow asymptomatic until being diagnosed by occasionally done radiologic examination. Missing tooth and malposition of adjacent teeth should induce clinicians to perform X-Ray diagnostic.

METHODS

A 37-year-old, male patient was admitted with a hopeless tooth 36, to be extracted and replaced with an implant. Clinical examination revealed also missing one of lower incisors and malposition of remaining lower incisors. Cone-beam computed tomography revealed horizontally impacted lower incisor surrounded by bone defect - 15 × 20 × 8 mm with the bone thickness remaining only 3.5 mm in the narrowest area. The basis on strong masticatory muscles and low thickness of bone after surgical removal of tooth and lesion, prophylactic osteosynthesis was planned. To explain the surgery to the patient model of the mandible was 3D printed.

RESULTS

Two treatment plans were presented to the patient: 1. custom plate production according to the bone defect and the shape of remaining bone and 2. choosing a standard plate and adjusting it on the 3D printed model. Costs of the material were 10 times higher in a custom solution. Plan 2 was then accepted. 1.2 mm straight plate was prebend on the model and sterilized. Lesion and impacted tooth were removed in local anesthesia. Prepared plates were fixed.

CONCLUSIONS

In the presented case custom 3D printed osteosynthesis plate was about 10 times more expensive compared to the standard osteosynthesis plate used. 3D printing of bone model may be helpful for prebending chosen standard plate and planning the surgery.

Automatic Real-Time Space Registration Application for Simulating Dental and Maxillofacial Surgery

ABSTRACT

Real-time surgical navigation systems are important for preoperative planning and intraoperative navigation. Automatic preoperative multimodal data registration and postoperative spatial registration are extremely crucial in such surgical navigation systems. However, existing automatic multimodal data registration methods have extremely limited application scope due to the lack of accuracy and speed. In addition, the registration results obtained by existing methods are practically lacking and are rarely applied in clinics. To address the above issues, this paper proposes a novel real-time teeth registration algorithm with computed tomography (CT) data and optical tracking scanning data. The proposed method is based on the weighted iterative closest point (ICP) algorithm with 3 improvements: (1) the multilayer spherical point set is generated inside the laser scanning marker sphere, (2) the weight decreases from inside to outside layer by layer, and (3) the weight of the voxel center point set is combined with the CT data of the marker sphere. Specifically, the proposed ICP registration method can overcome the limitation of surface point set registration and tackle the problem of high surface deformity of laser scanning marker spheres. For the registration result of CT and scanning data, the authors employ the real-time spatial registration algorithm based on optical tracking to complete the navigation of the simulated surgical instruments on the multimodal fusion image. The experimental results show that the proposed ICP algorithm reduces the mean square error by 1 order of magnitude and that our method has strong practical value.

Prosthetic Surgical Templates and Dental Implant Site Time Preparation: An In Vitro Study

Numerous types of prosthodontics surgical guides, with and without metallic sleeves, have been found to be useful in clinical studies. The aim of this in vitro research was to compare the time required to complete the surgical procedure with two differently designed surgical prosthetic templates. Ten identical prototype models of mandible based on a CBCT and optical scan of a partially edentulous patient with missing teeth numbers 37, 46, and 47 were prepared and then printed. Five of these models were used for implant site preparation with a surgical guide without metal sleeves and dedicated surgical kit, and the other five models were used for the same procedure performed with a surgical guide with metal sleeves and a dedicated surgical kit. The time of implant site preparation was measured and recorded. Statistical analysis was performed using Student’s t-test for independent samples. Differences between groups were found to be statistically significant (t = −9.94; df = 28; p = 0.0000) with a lower value in favor of the surgical templates without metallic sleeves. Different types of prosthodontics surgical guides, with or without metallic sleeves, seemed to be an important factor which can significantly impact the time of implant site preparation and, therefore, the overall surgical procedure.

Comparison of dentoskeletal and soft tissue changes between tooth-borne and tooth-bone-borne hybrid nonsurgical rapid maxillary expansions in adults: a retrospective observational study

BACKGROUND

Despite the gradual increase in the use of rapid maxillary expansion (RME), specifically RME with the aid of skeletal anchorage in adults, there have been no reports comparing dentoskeletal and soft tissue changes between nonsurgical tooth-borne and tooth-bone-borne RMEs in adults. This study aimed to analyse differences in dentoskeletal and soft tissue changes between tooth-borne and tooth-bone-borne RMEs using a similar appliance design and the same expansion protocol in adult patients.

METHODS

Twenty-one patients with tooth-borne expansion (a conventional expansion screw with two premolars and two molar bands for dental anchorage [T-RME]) and the same number of patients with tooth-bone-borne hybrid expansion (a conventional expansion screw with two premolar and two molar bands for dental anchorage and four mini-implants in the palate for skeletal anchorage [H-RME]) were included. Dentoskeletal and soft tissue variables at pretreatment (T1) and after expansion (T2) were measured using posteroanterior and lateral cephalograms and frontal photographs. The sex distribution of the two groups was analysed using the chi-square test, and the change after RME in each group was evaluated using the Wilcoxon signed-rank test. Differences in pretreatment age, expansion duration, post-expansion duration, and dentoskeletal and soft tissue changes after RME between the two groups were determined using the Mann-Whitney U test.

RESULTS

There were no significant differences in the expansion protocol, pretreatment conditions, and sex distribution between the two groups. Despite similar degrees of dental expansion at the crown level between the two groups, H-RME induced increased skeletal and parallel expansion of the maxilla compared to T-RME. After expansion, H-RME demonstrated increased forward displacement of the maxilla without significant changes in the vertical dimension, while T-RME exhibited increased backward displacement of the mandible, increased vertical dimension, and decreased overbite. Both groups showed significant retroclination and extrusion of the maxillary incisors without significant intergroup differences. There were no significant soft tissue changes between the two groups.

CONCLUSION

This study suggests that using skeletal anchorage in RME may induce increased skeletal and parallel expansion of the maxilla without significant effects on the vertical dimension.

A multi-patient analysis of the center of rotation trajectories using finite element models of the human mandible

Studying different types of tooth movements can help us to better understand the force systems used for tooth position correction in orthodontic treatments. This study considers a more realistic force system in tooth movement modeling across different patients and investigates the effect of the couple force direction on the position of the center of rotation (CRot). The finite-element (FE) models of human mandibles from three patients are used to investigate the position of the CRots for different patients’ teeth in 3D space. The CRot is considered a single point in a 3D coordinate system and is obtained by choosing the closest point on the axis of rotation to the center of resistance (CRes). A force system, consisting of a constant load and a couple (pair of forces), is applied to each tooth, and the corresponding CRot trajectories are examined across different patients. To perform a consistent inter-patient analysis, different patients’ teeth are registered to the corresponding reference teeth using an affine transformation. The selected directions and applied points of force on the reference teeth are then transformed into the registered teeth domains. The effect of the direction of the couple on the location of the CRot is also studied by rotating the couples about the three principal axes of a patient’s premolar. Our results indicate that similar patterns can be obtained for the CRot positions of different patients and teeth if the same load conditions are used. Moreover, equally rotating the direction of the couple about the three principal axes results in different patterns for the CRot positions, especially in labiolingual direction. The CRot trajectories follow similar patterns in the corresponding teeth, but any changes in the direction of the force and couple cause misalignment of the CRot trajectories, seen as rotations about the long axis of the tooth.

Hard Tissue Preservation and Recovery in Minimally Invasive Alveolar Surgery Using Three-Dimensional Printing Guide Plate

BACKGROUND

For completely impacted teeth, it is of great significance to locate teeth accurately, preserve hard tissue and recovering the height of alveolar ridge. This can be effectively solved by the digital three-dimensional printing guide technology.

METHODS

Ten patients with completely impacted tooth were selected in this experiment. After cone-beam computed tomography scan, the dicom formal computed tomography data was analyzed for three-dimensional reconstruction by mimics 17.0 software. Then determining the surgical plan and making surgical guide plate. Three-dimensional printing guide plate assisted piezosurgery was used to remove bone and extract impacted teeth. After that, the removed bone cap was back to the original position. Cone-beam computed tomography was used for each operated patients after 1 week and 6 months.

RESULT

The surgical guide plates can locate teeth accurately and the surgery time was reduced for all patients. A week later, all patients healed well and removed the stitches on time. Cone-beam computed tomography showed that the retention of bone caps was good and there was no displacement. All patients showed a normal parameter of pain. Six months later, cone-beam computed tomography showed good bone formation in the extraction area, which filled with new bones completely. The recovery of bone outline and height of alveolar crest at the surgical site were basically consistent with those before the operation.

CONCLUSIONS

Three-dimensional printing guide plates combining with fenestration and bone-cap restoration can locate impacted teeth accurately, reduce the extraction volume of bone, shorten surgery time, and alleviate complications. This was conducive to preserve and restore hard tissue and had great prospective.

Correction of Traumatic Transverse Mandibular Widening With Interdental Wiring

ABSTRACT

Mandibular symphysis fractures pose several technical challenges for the craniomaxillofacial surgeon. One classic challenge is restoration of the transverse dimension when the mandible is widened secondary to splaying of the lingual cortex. Failure to diagnose or correct this problem can result in widening of the lower facial third, inadequate fracture reduction, and/or a malocclusion. Surgeons have traditionally utilized techniques such as manual pressure to the rami or lingual splint application to address transverse defects intraoperatively. However, these methods may be inadequate in situations with significant widening, such as in the case of concomitant subcondylar fractures. More recently, virtual surgical planning and custom hardware have been utilized to address mandibular widening, though this method also has various shortcomings. In this technical note, the authors present a simple technique using interdental wiring to precisely control mandibular width intraoperatively. The technique is cost effective, does not require an assistant, and can be used in conjunction with any of the above methods. The authors also present a case of secondary reconstruction in which use of this technique was necessary given a large degree of mandibular widening not amenable to reduction and fixation with manual pressure alone.

Placement of a customised load-bearing titanium plate for prevention of iatrogenic mandibular fracture in surgical removal of odontogenic keratocyst recurrence

A 72-year-old woman with a history of removal of a right hemimandibular keratocyst 10 years ago was referred to our attention for a large swelling of the right cheek. The orthopantomography and the CT scan showed a huge osteolytic area of the right mandibular ramus and angle. The patient's refusal to resection and reconstruction with a free flap pushed us towards a conservative treatment. The high probability of a iatrogenic mandibular fracture during and after surgery required the design of a customised titanium plate to be preliminary placed through cervical incision along the posterior border of the mandible. The patient successfully underwent the surgical positioning of the customised plate and subsequent removal of the keratocyst. She was discharged fit and well 5 days after surgery. She did not experience any infections, pathological fractures or relapse in the 6-month follow-up.

In Vitro Comparison of Time and Accuracy of Implant Placement Using Trephine and Conventional Drilling Techniques Under Dynamic Navigation

The aim of this randomized in vitro study was to compare the time and accuracy of implant-site preparation and implant placement using a trephine drill versus a conventional drilling technique under dynamic navigation. In total, 42 implants were placed in simulation jaw models with the 2 drilling techniques by 2 operators who had previous experience with dynamic navigation. The timing of each implant placement was recorded, and horizontal, vertical, and angulation discrepancies between the planned and placed implants were compared. There was no significant difference in time or accuracy between the trephine and conventional drilling techniques. Implant-site preparation with a single trephine drill using dynamic navigation was as accurate under in vitro experimental conditions as a conventional drilling sequence.

In Vitro and In Vivo Assessment of a New Workflow for the Acquisition of Mandibular Kinematics Based on Portable Tracking System with Passive Optical Reflective Markers

Clinical use of portable optical tracking system in dentistry could improve the analysis of mandibular movements for diagnostic and therapeutic purposes. A new workflow for the acquisition of mandibular kinematics was developed. Reproducibility of measurements was tested in vitro and intra- and inter-rater repeatability were assessed in vivo in healthy volunteers. Prescribed repeated movements (n = 10) in three perpendicular directions of the tracking-device coordinate system were performed. Measurement error and coefficient of variation (CV) among repetitions were determined. Mandibular kinematics of maximum opening, left and right laterality, protrusion and retrusion of five healthy subjects were recorded in separate sessions by three different operators. Obtained records were blindly examined by three observers. Intraclass correlation coefficient (ICC) was calculated to estimate inter-rater and intra-rater reliability. Maximum in vitro measurement error was 0.54 mm and CV = 0.02. Overall, excellent intra-rater reliability (ICC > 0.90) for each variable, general excellent intra-rater reliability (ICC = 1.00) for all variables, and good reliability (ICC > 0.75) for inter-rater tests were obtained. A lower score was obtained for retrusion with “moderate reliability” (ICC = 0.557) in the inter-rater tests. Excellent repeatability and reliability in optical tracking of primary movements were observed using the tested portable tracking device and the developed workflow.

Virtual Surgical Planning and Three-Dimensional Printing to Aid the Anatomical Reduction of an Old Malunited Fracture of the Mandible

ABSTRACT

Mandible fracture is a common injury in maxillofacial surgery. It causes not only maxillofacial dysfunction but also facial deformities. Malunited fractures of the mandible have been a vast challenge in clinical treatment due to the misalignment of the broken ends and the occurrence of occlusal disorders. This case report describes using virtual surgical planning and three-dimensional printing to treat a patient with malunited fracture of the mandible. Failing to perform mandibular surgery due to severe brain trauma after the car accident, the patient got malunited healing of mandible. The authors applied virtual surgical planning to perform preoperative analysis and surgical design on this patient, three-dimensional printing to fabricate occlusal plate, and models of the preoperative and postoperative mandible to guide the operation. Finally, the authors achieved the reduction and reconstruction of the mandible with satisfactory clinical results.

Scoping Zygomaticomaxillary Complex Fractures With the Eyes of Virtual Reality: Operative Protocol and Proposal of a Modernized Classification

INTRODUCTION

Fractures of the zygomaticomaxillary complex (ZMC) represent an extremely heterogeneous group of injuries to the midfacial skeleton. Traditionally, the diagnosis of such fractures was based on 2-dimensional radiograms and, more recently, on volumetric computed tomography (CT) scans, while the treatment was exclusively based on the surgeon's experience. Many classification attempts have been made in the past, but no paper has taken into account the importance of virtual surgical planning (VSP) in proving a modernized classification. The authors propose a classification based on the use of VSP which can guide the surgeon to identify the optimal reduction method and reproduce it in the operating room through the use of navigation.

METHODS

Patients with ZMC fractures were collected to create a study model. The VSP was used to generate 3-dimensional models of fractures. Fractured segments were duplicated and digitally put in the optimal reduction position. Repositioned fragments were overlapped to their original preoperative counterparts and exported to the surgical navigator to be navigated. Planned virtual reduction was overlaid to postoperative CT scan to assess the accuracy of reduction, explored using color maps and the calculation of root mean square error.

RESULTS

For all patients, the application of VSP was successfully accomplished. High accuracy was confirmed between the planned virtual reduction and the postoperative CT scan. A 5-item classification based on VSP is proposed. All patients were included in the presented subclasses.

CONCLUSIONS

The adoption of virtual planning in ZMC fractures allows for an improved study of the displacement of the fracture and might indicate to the surgeons the required maneuvers to achieve optimal reduction. The presented proposal of classification might be an aid to simplify the choice of the most appropriate reduction method and might provide a deeper insight into the morphologic characteristics of fractures.

Esthetic treatment planning with digital animation of the smile dynamics: A technique to create a 4-dimensional virtual patient

A method is presented for obtaining a virtual 4-dimensional patient that replicates the intended esthetic treatment. The process involves facial and intraoral scanning to acquire records and software manipulation to enable a virtual waxing of the smile. Once the digital design is complete, patient information can be merged to generate an animated video of the projected rehabilitation, displaying movement and smile dynamics. This strategy provides a noninvasive and reliable diagnostic tool for predicting clinical outcomes.

Fully automated estimation of arch forms in cone-beam CT with cubic B-spline approximation: Evaluation of digital dental models with missing teeth

BACKGROUND AND OBJECTIVE

To evaluate the automatic determination method for the arch form in cone-beam computed tomography (CBCT) images with cubic B-spline approximation on digital dental models using various types of missing teeth.

METHODS

The maxilla and mandible from eight dental CBCT images with Class I occlusion and no missing teeth were used in this study. The dental arch determination algorithm using cubic B-spline approximation was modified by applying a smoothing function for reliable curve fitting to the digital dental models with various types of missing teeth. For evaluation, 31 scenarios with missing teeth were simulated, and cases with 1-8 missing teeth were divided into three groups: solitary, consecutive, and multiple (more than 4) missing teeth. The prediction accuracies of the dental arch forms were evaluated through comparisons with the gold standards for the digital dental models by two expert orthodontists.

RESULTS

The distance errors between the gold standards and the estimated results of the dental arch forms in all types of models were 0.237-1.740 mm. The mean distance errors of the solitary, consecutive, and multiple groups were 0.436 ± 0.124 mm (0.237-0.964 mm), 0.591 ± 0.250 mm (0.256-1.482 mm), and 0.679 ± 0.310 mm (0.254-1.740 mm), respectively.

CONCLUSIONS

The algorithm for predicting the arch form functioned reliably, even for digital dental models with various types of missing teeth, and could be applied to digital dentistry for applications such as orthodontic tooth setup, artificial tooth arrangement for denture fabrication, and implant guides.

The Effect of Perioral Scan and Artificial Skin Markers on the Accuracy of Virtual Dentofacial Integration: Stereophotogrammetry Versus Smartphone Three-Dimensional Face-Scanning

This study evaluated the effects of different matching methods on the accuracy of dentofacial integration in stereophotogrammetry and smartphone face-scanning systems. The integration was done (N = 30) with different matching areas (n = 10), including teeth image only (TO), perioral area without markers (PN) and with markers (PM). The positional accuracy of the integrated models was assessed by measuring the midline linear deviations and incisal line canting between the experimental groups and laser scanner-based reference standards. Kruskal–Wallis and Mann–Whitney U tests were used for statistical analyses (α = 0.05). The PM method exhibited the smallest linear deviations in both systems; while the highest deviations were found in the TO in stereophotogrammetry; and in PN in smartphone. For the incisal line canting; the canting degree was the lowest in the PM method; followed by that in the TO and the PN in both systems. Although stereophotogrammetry generally exhibited higher accuracy than the smartphone; the two systems demonstrated no significant difference when the perioral areas were used for matching. The use of perioral scans with markers enables accurate dentofacial image integration; however; cautions should be given on the accuracy of the perioral image obtained without the use of markers.

Accuracy of Portable Face-Scanning Devices for Obtaining Three-Dimensional Face Models: A Systematic Review and Meta-Analysis

The use of three-dimensional face-scanning systems to obtain facial models is of increasing interest, however, systematic assessments of the reliability of portable face-scan devices have not been widely conducted. Therefore, a systematic review and meta-analysis were performed considering the accuracy of facial models obtained by portable face-scanners in comparison with that of those obtained by stationary face-scanning systems. A systematic literature search was conducted in electronic databases following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines for articles published from 1 January 2009 to 18 March 2020. A total of 2806 articles were identified, with 21 articles available for the narrative review and nine studies available for meta-analysis. The meta-analysis revealed that the accuracy of the digital face models generated by the portable scanners was not significantly different from that of the stationary face-scanning systems (standard mean difference (95% confidence interval) = -0.325 mm (-1.186 to 0.536); z = -0.74; p = 0.459). Within the comparison of the portable systems, no statistically significant difference was found concerning the accuracy of the facial models among scanning methods (p = 0.063). Overall, portable face-scan devices can be considered reliable for obtaining facial models. However, caution is needed when applying face-scanners with respect to scanning device settings, control of involuntary facial movements, landmark and facial region identifications, and scanning protocols.

Role of New Hydrophilic Surfaces on Early Success Rate and Implant Stability: 1-Year Post-loading Results of a Multicenter, Split-Mouth, Randomized Controlled Trial

OBJECTIVE

 To compare early implant failure and implant stability of one-stage Hiossen ET III implants with its new hydrophilic (NH) surface, compared with Hiossen ET III implants with the sandblasted and acid-etched (SA) surface at 1-year follow-up.

MATERIALS AND METHODS

 This study was designed as a split-mouth, multicenter randomized controlled trial aimed to compare SA surface implants (SA group) and NH surface, (NH group). Outcomes were implant and prosthetic survival rates, complications, the insertion torque at implant placement, and implant stability quotient (ISQ) values.

RESULTS

 Twenty-nine patients (mean age 59.9 ± 11.3 years) were treated and followed up to 1 year after loading. No patient dropped out. Fifty-eight implants (29 SA group and 29 NH group) were placed. No implants or prostheses failed and no complications were experienced during follow-up. The mean insertion torque was 40.5 ± 3.23 (38.17-41.83) Ncm in the SA group and 40.48 ± 3.49 (38.02-41.98) Ncm in the NH group (p = 0.981). There was a statistically significant difference at the second week (T2) with higher values in the NH group (p = 0.041). Similar results were found in the maxilla (p = 0.045), but not in the mandible (p = 0.362). A positive correlation was found between initial insertion torque and ISQ with higher value in the NH group (0.73 vs. 0.66).

CONCLUSIONS

 NH implants are a viable alternative to SA surface, as they seem to avoid the ISQ drop during the bone remodeling phase.

Predictive Model for Occlusal Vertical Dimension Determination and Digital Preservation with Three-Dimensional Facial Scanning

(1) Background: Occlusal vertical dimension (OVD) in the optimal maxillo–mandibular relationship is an important parameter to establish when complex dental rehabilitation has to be done. The optimal method to measure OVD is still a challenge in everyday practice. The aim of the present study was to test the reliability of the correlation between OVD and some anthropometric and cephalometric methods described in the literature. The validity of OVD registration using a facial scanner was also assessed. (2) Materials and Methods: 150 dentate participants, aged 20–25 years, were randomly selected using sealed envelopes. Anthropometric measurements between specific standard points were performed: Subnasion–Prementon (Sn–PM) and Subnasion–Gnation (Sn–Gn) in maximum intercuspation and in the rest mandibular position, right and left pupil to the corresponding chelion. The cephalometric measurements registered were the lower facial angle and the angle between mandibular and Frankfurt planes. The distance Sn–Gn in maximum intercuspation was compared to all other parameters. Facial scanning, with a mobile phone and installed dedicated application, was performed on ten subjects, randomly selected using the same method among the participants, and the obtained 3D files were analyzed. The digital measurements were compared, for validity, to the clinical measurements. Pearson’s correlation coefficient was used, for comparing clinical Sn–Gn in maximum intercuspation position to the other parameters. (3) Results: A strong agreement between all measured anthropometric parameters of the facial scan and clinical contact measurement method was registered. None of the measured parameters could predict the exact OVD. (4) Conclusions: In the limits of our study, the facial scanning could be used for predictable registration of OVD and the stored digital information could be preserved through life and use for oral rehabilitation. However, if OVD needs to be determined, several measurement methods, including cephalometric measurements, need to be used simultaneously to reach a final decision.

Customized composite veneers from a totally digital workflow: A case report

A treatment plan based on the use of a preview software can offer the possibility to rapidly communicate with the patient. Fully digital workflow allows for making several objects at the same time in a precise and cost-efficient manner.

Mandibular Angle Contouring Using Porous Polyethylene Stock or PEEK-based Patient Specific Implants. A Critical Analysis

ABSTRACT

Contour augmentation and mandibular angle modification surgery is becoming increasingly. The aim of this research is to compare technique and outcomes in augmentations done with standard implants or PEEK-based patient specific implants (PSI) in mandibular angle. Data from surgical planning, operative and post-operative of 6 months follow-up were revised for 21 patients who were submitted to facial surgery using a stock implant obtained from companies currently on the market or 3D implants created with CAD/CAM technology using PEEK 3D printing. Surgical time, intra-operative and post-operative complications were compared, analyzing the advantages and disadvantage of each technique. Statistical analyses using t-test and chi-squared were performed considering P value< 0.05 for statistical differences. Twelve patients were operated on with stock implants and nine patients with PSI. The surgical time was 15 minutes less for the 3D implant surgeries (P = 0.021) and intraoperatively only the stock implants needed modifications with wear and adaptation methods; post-operative infections were observed in both groups with no significant differences (P > 0.05). The 3D implants had greater levels of facial symmetry than the stock implants, although they did not present significant differences.Considering the limitations of this study, mandibular angle implants with a PEEK-based 3D CAD/CAM are efficient, stable and have a low complication rate; the CAD/CAM strategy is useful in facial surgery and can be integrated as a standard for surgical planning in facial makeover surgery.

Assessment of the configuration of the mandibular canal using cone beam computed tomography

BACKGROUND

During dental implants placement and bone augmentation procedures, it is important to determine the presence and location of mandibular canal anatomical variation in order to avoid injuries to inferior alveolar bundle. This study aimed to describe the prevalence and configuration of mandibular canal branching in the posterior region of the mandible using cone beam computed tomography (CBCT).

METHODS

The interpretation of the images was conducted according to the presence, classification and location of the mandibular canal. Horizontal and vertical distances from mandibular canal in the ramus region to the molar region was recorded. CBCT images of 751 patients, 486 women (64.7%) and 265 men (35.3%), with a mean age of 54.57 (±13.23; 14-93) years, were interpreted by one calibrated examiner.

RESULTS

Out of 1502 hemi-mandibles images, mandibular canal variations were observed in 130 (8.6%). Sixty-four (49.2%) mandibular canal variations were identified on the right side and 66 (50.8%) on the left side. The mean distances between superior cortical of the mandibular canal and the base of mandible, buccal cortical of mandibular canal and buccal cortical bone, and superior cortical of mandibular canal and alveolar ridge were 12.16 mm (±2.68), 4.17 mm (±1.30), and 12.97mm (±4.01), respectively. Type I mandibular canal variation was the most frequent (68; 52.2%), followed by type III (34; 26.1%).

CONCLUSIONS

Prevalence of mandibular canal variations was 8.6%, type I was the most common and its direction showed proximity with lingual surface in the second molar region.

Surgery First and Invisalign System: Combined Digital Approach

PURPOSE

The aim of the present paper is to verify the long-term results in dental and skeletal stability in terms of symmetry, occlusion and functional balance by the association between the IS and the SF technique.

METHODS

In this paper, the authors described 12 cases of severe class III malocclusion treated by the association between the IS and the SF technique.

RESULTS

At 1 year of post-orthodontic follow up, the patients present an Angle class I occlusal relationship, no deep bite, no scissor or cross-bite and no open bite. No one patient referred TMJ discomfort nor severe post-surgical complications and no surgical-orthodontic relapse occurred. The surgical and occlusal results are stable in terms of stability in all patients.

CONCLUSION

The results of this study suggest the validity of our protocol in management of class III malocclusion patients.

Implant-Supported Prosthetic Therapy of an Edentulous Patient: Clinical and Technical Aspects

The purpose of this article is to show how to implement an implant-supported prosthetic overdenture using a digital workflow. Esthetic previewing using a specific software, guided-surgery, construction of the prosthesis, and the esthetic finalization are described in this article. Patients suffering from severe loss of bone and soft tissue volume could benefit from the construction of an overdenture prosthesis as a feasible therapeutic choice for functional and esthetic issues of the patient.

A Review on the Biocompatibility of PMMA-Based Dental Materials for Interim Prosthetic Restorations with a Glimpse into their Modern Manufacturing Techniques

This paper's primary aim is to outline relevant aspects regarding the biocompatibility of PMMA (poly(methyl methacrylate))-based materials used for obtaining interim prosthetic restorations, such as the interaction with oral epithelial cells, fibroblasts or dental pulp cells, the salivary oxidative stress response, and monomer release. Additionally, the oral environment's biochemical response to modern interim dental materials containing PMMA (obtained via subtractive or additive methods) is highlighted in this review. The studies included in this paper confirmed that PMMA-based materials interact in a complex way with the oral environment, and therefore, different concerns about the possible adverse oral effects caused by these materials were analyzed. Adjacent to these aspects, the present work describes several advantages of PMMA-based dental materials. Moreover, the paper underlines that recent scientific studies ascertain that the modern techniques used for obtaining interim prosthetic materials, milled PMMA, and 3D (three-dimensional) printed resins, have distinctive advantages compared to the conventional ones. However, considering the limited number of studies focusing on the chemical composition and biocompatibility of these modern interim prosthetic materials, especially for the 3D printed ones, more aspects regarding their interaction with the oral environment need to be further investigated.

Worldwide 3D Printers against the New Coronavirus

The pandemic caused by the new coronavirus has placed national health systems of different countries in difficulty, and has demonstrated the need for many types of personal protective equipment (PPE). Thanks to the advent of new three-dimensional printing technologies, it was possible to share print files (using stereolithography (stl)) quickly and easily, improve them cooperatively, and allow anyone who possessed the materials, a suitable 3D printer and these files, to print. The possibility of being able to print three-dimensional supports, or complete personal protective equipment has been of incredible help in the management of COVID-19 (Coronavirus Disease 2019). The times and the relatively low costs have allowed a wide diffusion of these devices, especially for the structures that needed them, mainly healthcare facilities. 3D printing, now includes different fields of application, and represents, thanks to the evolution of methods and printers, an important step towards the “digital world”.

Computerization and Digital Workflow in Medicine: Focus on Digital Dentistry

Continuously evolving technologies make dentistry one of the most advanced sectors in the field of medicine. The digital improvements in recent years have brought many advantages to clinicians and patients, including reduced working times, lower costs and increased efficiency of performance. Some of the most important digital technologies introduced in the dental filed are cone beam computer tomography (CBCT) scan, Computer Aided Design/Computer Aided Manufacturing (CAD-CAM) systems, and intraoral scanners. All of these allow faster and more accurate rehabilitations, with the opportunity of pre-simulation of the final treatment. The evolution of computer science has brought significant advantages in the medical and dental fields, making the diagnosis and execution of even complex treatments, such as implantology and bone reconstruction, possible. The digital world is trying to supplant the traditional analog workflow, and over time, with the further advance of technologies, it should tend to be the treatment of choice of our patients.

A New Method of Measuring the Volumetric Change of Alveolar Bone Around Dental Implants Using Computed Tomography

This study proposes a method for measuring the volumetric change of alveolar bone after dental implant surgery using computed tomography (CT). A total of 40 implants in 20 patients (15 males and 5 females) were selected. The types of implants used were group 1: 24 CMI IS-II Active implants (Neobiotech Co., Seoul, Republic of Korea) and group 2: 16 SLActive Bone Level implants (Institut Straumann AG, Basel, Switzerland). The OnDemand3D software (CyberMed, Seoul, Korea) was used for analysis. The volumetric change of the alveolar bone around an implant fixture is measured as follows: (1) Establish two cylinders: the main cylinder with the implant axis as the central axis (radius of implant + 3 mm) and the error correction cylinder (radius of implant + 1 mm). (2) The height of the cylinder extended from the top of the fixture to a 3 mm coronal portion. (3) Calculate the volumetric change of the alveolar bone (Vd) by subtracting the volume of the error correction cylinder from the main cylinder between CT images taken immediately after the implant placement and 12 months later. After a one-year installation, the volumetric change of alveolar bone, ΔV (cc) had increased in both groups (group 1: −0.011 ± 0.015 cc, group 2: −0.012 ± 0.017 cc) with statistical significance (p < 0.05), and the difference between the groups was not statistically significant (p > 0.05). This three-dimensional assessment method would be a useful clinical reference for the assessment of marginal bone change after implant surgery.

3D Digital Impression Systems Compared with Traditional Techniques in Dentistry: A Recent Data Systematic Review

The advent of new technologies in the field of medicine and dentistry is giving improvements that lead the clinicians to have materials and procedures able to improve patients' quality of life. In dentistry, the last digital techniques offer a fully digital computerized workflow that does not include the standard multiple traditional phases. The purpose of this study is to evaluate all clinical trials and clinical randomized trials related to the digital or dental impression technique in prosthetic dentistry trying to give the readers global information about advantages and disadvantages of each procedure. Data collection was conducted in the main scientific search engines, including articles from the last 10 years, in order to obtain results that do not concern obsolete impression techniques. Elsevier, Pubmed and Embase have been screened as sources for performing the research. The results data demonstrated how the working time appears to be improved with digital workflow, but without a significant result (P = 0.72596). The papers have been selected following the Population Intervention Comparison Outcome (PICO) question, which is related to the progress on dental impression materials and technique. The comparison between dentists or practitioners with respect to classic impression procedures, and students open to new device and digital techniques seem to be the key factor on the final impression technique choice. Surely, digital techniques will end up supplanting the analogical ones altogether, improving the quality of oral rehabilitations, the economics of dental practice and also the perception by our patients.

Spine and TMJ: A Pathophysiology Report

The relationship between posture, spine, and temporomandibular joint (TMJ) is still a hotly debated topic in medicine. TMJ takes part in different physiological functions of the organism, starting from its embryological development, it is possible that it influences different vital functions. There is a strong connection between the respiratory tract and dental/maxillary occlusion or anatomy. The altered physiology of this district leads to pathologies that could affect the whole organism. On the contrary, it is also possible to highlight some symptoms of distant organism districts. Knowing well the pathophysiology of this district and semiotics, it is also possible to diagnose pathologies affecting other organs.