Dental Restorative Digital Workflow: Digital Smile Design from Aesthetic to Function

Perceptions in Digital Smile Design: Assessing Laypeople and Dental Professionals' Preferences Using an Artificial-Intelligence-Based Application

Digital Smile Design (DSD) is used in many fields of dentistry. This prospective observational study assessed laypeople's and dental professionals' perceptions of a DSD application. SmileCloud, an online DSD platform, was used to create two different designs for three patients; after that, the participants, in a 30-question online illustrated survey, were asked about the most attractive design and other features of the smile. Dentists' and laypeople's perceptions about specific DSD features were assessed. The Kolmogorov-Smirnov normality test was used. Descriptive and crosstab analyses compared the respondents' opinions for each statement. Chi-square tests were used to determine the relationship between the questions and any association with age, gender, and profession. The test results were rated as significant at a p-value < 0.05. A total of 520 participants (dental professionals, students, dental technicians, and laypeople) were enrolled. The statistically significant features were self-esteem related to appearance (p = 0.05), facial and smile symmetry (p = 0.42, p < 0.0001), tooth color (p = 0.012), and symmetry of gums (p < 0.001). For each patient, the design with dominant round upper incisors and perfect symmetry was preferred (p < 0.001). Digital pre-visualization benefits diagnosis and enriches treatment planning. The dentist-dental technician-patient team should be involved in the decision-making process of pre-visualization.

Integrating digital smile design into restorative Dentistry: A narrative review of the applications and benefits

The primary goal of esthetic treatment is to ensure patient satisfaction and meet their expectations of improving their facial esthetics and smile. However, some patients may have doubts regarding the irreversible nature of the treatment. In such cases, the Digital Smile Designing (DSD) technique can be employed to educate and motivate patients. DSD is a technical tool that allows digital designing and modification of a patient's smile, enabling them to visualize the potential outcomes before the actual treatment begins. This technique facilitates visual communication and patient involvement in the smile design process, leading to predictable treatment results and higher acceptance rates. This article provides an overview of DSD in esthetic dental practice and discusses its applications, advantages, limitations, and future possibilities.

Complete mouth rehabilitation in a patient with condylar fracture malunion: A clinical report

Mandibular condyle fracture malunion and tooth loss can cause functional and esthetic problems. A patient with restricted mouth opening associated with muscle atrophy required prosthetic rehabilitation. Since the remaining teeth had a poor prognosis and the patient had difficulty adapting to the interim denture, complete mouth rehabilitation with implants was chosen. The implants were placed by using nerve lateralization and an autogenous bone graft. Prosthetic rehabilitation combines digital diagnosis and conventional prosthetic restorations. The definitive prosthesis was fabricated to ensure adequate oral hygiene and functional adaptation of the orofacial structures. Treatment resulted in stable masticatory function, occlusion, and esthetics and restored the function of the atrophied lips and restricted mouth opening.

Aesthetic treatment planning simplified using digital smile design: A case report

Digital smile design (DSD) plays an essential role in the planning of aesthetic treatments. However, most digital smile designing software programmes are expensive and require specialised training and skill for effective implementation. This paper illustrates the use of Adobe Photoshop and Microsoft PowerPoint, which are economical and user friendly for planning aesthetics in a clinical case.

Computer aided design/computer aided manufacturing (CAD/CAM) technology in the undergraduate dental programs in the MENA region

INTRODUCTION

The aim of this study was to understand the trends of teaching Computer Aided Design/Computer Aided Manufacturing (CAD/CAM) in the undergraduate dental curriculum in the MENA region by conducting an online survey among the undergraduate dental colleges in this region.

MATERIALS AND METHODS

An online survey was conducted using Google Forms consisting of 20 questions that could be answered by "yes" or "no" responses, multiple-choice answers or in a descriptive, "open" format. A total of 55 participants from the MENA region representing their dental college were requested to participate in this study.

RESULTS

The response rate of the survey was 85.5% following the twofold follow-up reminders method. Although the vast majority of professors demonstrated vital knowledge in the practical use of CAD/CAM, the majority of them did not provide theoretical and practical training on CAD/CAM in their institutions. Among the schools with established levels of teaching CAD/CAM, nearly 50% of them provide both pre-clinical and clinical training on CAD/CAM. Despite the availability of extra-curricular training courses on CAD/CAM outside the university setting, there is a lack of advocating for students to enrol in those courses by the institutions. More than 80% of the participants agreed that CAD/CAM has a strong future in chair-side dental clinics and CAD/CAM needs to be incorporated within undergraduate studies.

CONCLUSION

Based on the results of the current study, it is understandable that an intervention is required by the dental education providers to cope with the growing demand for CAD/CAM technology for the current and future dental practitioners of the MENA region.

Research Progress and Clinical Application of All-Ceramic Micro-Veneer

Anterior teeth problems affect the patient's daily eating, communication, social activities, self-confidence, and mental health. The trend in dentistry is to address anterior tooth problems with minimally invasive and aesthetic treatments. With the development of adhesive materials and ceramics, micro-veneers have been proposed as an alternative treatment for enhancing the aesthetic appearance and avoiding unnecessary tooth reduction. A micro-veneer is a veneer that can be cemented to the surface without or with minimal tooth preparation. These benefits include no need for anesthesia, postoperative insensitivity, good adhesion to enamel, reversibility of treatment, and higher patient acceptance. However, the micro-veneer repair is suitable only for specific cases and must be strictly controlled regarding indication. Treatment planning is a crucial step to achieving functional and aesthetic rehabilitation, and following the clinical protocol is helpful for the longevity and success of micro-veneer restorations. However, more precise and predictable tooth preparation methods, such as minimally invasive microscopic tooth preparation and digitally guided veneer preparation, are recommended rather than the traditional free-hand method. Therefore, this paper clarifies micro-veneers and compares them with other restorations to gain a deeper and more comprehensive understanding. The authors also review indications, materials, cementation, and effect evaluation of micro-veneers to provide clinicians with valuable information. In conclusion, micro-veneers are minimally invasive treatments that provide good restoration results when used appropriately and are worthy of promotion for the aesthetic restoration of anterior teeth.

Influence of different education approaches on the implantation performance of dental practitioners in aesthetic zone

PURPOSE

To investigate the influence of different education approaches on the implantation performance (operation time, three-dimensional deviation) of inexperienced operators.

METHODS

Eighteen students who met the inclusion criteria were randomly assigned to traditional training group or digital training group. After training, the average operation time and implant deviation (platform deviation, apex deviation, and angle deviation) of the two groups were calculated by Student's t-test. A self-developed questionnaire was used to evaluate the students' grasp of clinical knowledge and skill.

RESULT

Compared with the traditional training group, the duration of implant installation and temporary prosthesis placement of the digital training group decreased significantly (p < 0.05). The implant deviation of the digital training group was lower than that of the traditional training group. The apex deviation (p = 0.015) and angle deviation (p = 0.015) significantly improved with digital training, but differences in platform deviation (p = 0.065) were not statistically significant. The questionnaire survey showed that the overall perception of the inexperienced operators in the digital training group was better than that in the traditional training group.

CONCLUSION

In the hands of inexperienced operators, digital training reduced the operation time and improved the implant accuracy in comparison with traditional training.

Bioengineering Applied to Oral Implantology, a New Protocol: “Digital Guided Surgery”

Rehabilitative dentistry has made enormous progress in recent years, not only due to the advent of new implant-prosthetic methods, but also thanks to new information technologies that support the doctor. This study aims to present a new implant protocol that involves the application of bioengineering methods. With the application of the finite element analysis, it is possible to evaluate the distribution of the forces of a fixture and possible implant rehabilitation on each patient, even before performing the surgery. This protocol provides for the combination of radiographic images and three-dimensional files to obtain predictable results on possible rehabilitation, guiding its planning in the best possible way. Surely, the evolution of machines and computers will enable the surgeon to carry out and maintain these protocols in a chair-side manner, and to carry out safe and predictable rehabilitations.

Same-Day Digital Dentistry Restorative Workflow for Single Immediate Provisionalization of Narrow-Diameter Implants: An Exploratory Prospective Study

This study evaluated the two-year clinical outcomes of 3.1 mm diameter dental implants, immediately provisionalized and later restored using same-day dentistry, in 10 patients receiving 11 narrow-diameter (3.1 mm) single implants. Each implant was placed and immediately restored with a provisional crown after placement. At least 2 months after placement, the implant was restored with a prefabricated titanium abutment and an all-ceramic crown using a same-day dentistry protocol. Clinical outcomes, including apical bone loss, probing depths, gingival index, and surgical and prosthetic complications, were documented. There was no implant failure over the course of two years. No surgical complications were reported. Two cases lost provisional crowns. One crown needed to be remade due to esthetic concern. The cumulative two-year survival rate of the implants was 100%. Implant bone loss after two years of functional loading was −0.56 ± 0.54 mm and −0.32 ± 0.68 mm for mesial and distal crestal bone, respectively. Two prosthetic complications included recementation of a crown and remaking of a crown. This exploratory study suggests that immediate provisionalization and a same-day restorative dentistry digital workflow protocol for narrow-diameter implants appear to be predictable clinical procedures with no reported surgical complications and minimal prosthetic complications.

Silicone key device for maxilla orientation and occlusal plane recording in a digital workflow

This article describes a technique for recording the maxilla's orientation in esthetically driven oral rehabilitation and transferring its position by using computer-aided design and computer-aided manufacturing (CAD-CAM) technology. The protocol uses a Fox plane and a bubble level to orient an addition silicone key of the maxilla parallel to the occlusal reference plane. The silicone reference key was scanned, superimposed over the maxilla intraoral standard tessellation language (STL) file, and adequately oriented in a CAD software program.

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.

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.

Digital smile design

One of the important ways of social interaction is through verbal and nonverbal communication. The human face is capable of eliciting multi-response according to the situation; amongst them, a smile plays a significant effect in relaying a positive communication that can immensely influence societal outcomes. An important part of dental treatment is to restore the tooth to functionality and to esthetically rehabilitate it, which forms the core of esthetic dentistry. Modern advancements have led us to various esthetic treatment options. Recently, due to the boom of information technology, we are progressing into the digital age where everything has almost been made through computers and the internet. In the dental field, advanced software is being used to modify and create smiles, thereby completely revolutionizing esthetic dentistry. Digital smile design is a recently introduced concept and software which analyzes the smile of an individual through various input scanners and photographs. They provide a plethora of solutions and predictions as to how the smile can be designed, to the point it can pinpoint minor corrections. Here, we discuss the importance of smiles and the analysis using digital smile design.

Three-dimensional changes in the upper airway and craniomaxillofacial morphology of patients with Angle Class III malocclusion treated with a Frankel III appliance

BACKGROUND

Angle Class III malocclusion, characterized by a concave profile, can cause serious harm to children's physical and mental health. The Frankel III appliance is an effective treatment for Angle Class III malocclusion in mixed denition. We explored three-dimensional changes in the upper airway and craniomaxillofacial morphology, after one year of Frankel III appliance treatment, in children with Angle Class III malocclusion.

METHODS

We included 20 children (9 males), aged 8-10 years, with Angle Class III malocclusion from the Orthodontics Department of our hospital. Each child was treated with a Frankel III appliance for one year. Cone beam computed tomography was performed before and after treatment to evaluate three-dimensional changes in the upper airway and craniomaxillofacial morphology.

RESULTS

After one year of treatment, in the upper airway, we observed significant increases in the nasopharynx volume and height (P < 0.05); the velopharyngeal volume, height, and average cross-sectional area (P < 0.05); the glossopharynx volume and minimum cross-sectional area (P < 0.05); and the laryngopharynx height (P < 0.05). Accordingly, the total upper airway volume, height, and average cross sectional area increased significantly (P < 0.05). An examination of craniomaxillofacial morphology showed significant increases in some bone tissues (P < 0.05) and dental measurements, and a significant reduction in the inclination of the mandibular central incisor (P < 0.05).

CONCLUSION

Children with Angle class III malocclusion treated with a Frankel III appliance showed no upper airway narrowing, even after repositioning the mandible posteriorly. Moreover, treatment promoted forward maxilla development and increased its width, in both the dental arch and alveolar bone, which provided a more harmonious craniofacial morphology.

Integration of imaging modalities in digital dental workflows - possibilities, limitations, and potential future developments

The digital workflow process follows different steps for all dental specialties. However, the main ingredient for the diagnosis, treatment planning and follow-up workflow recipes is the imaging chain. The steps in the imaging chain usually include all or at least some of the following modalities: cone-beam computed tomographic data acquisition, segmentation of the cone-beam computed tomography image, intraoral scanning, facial three-dimensional soft tissue capture and superimposition of all the images for the creation of a virtual augmented model. As a relevant clinical problem, the accumulation of error at each step of the chain might negatively influence the final outcome. For an efficient digital workflow, it is important to be aware of the existing challenges within the imaging chain. Furthermore, artificial intelligence-based strategies need to be integrated in the future to make the workflow more simplified, accurate and efficient.

Versorgung junger Patienten mit kraniofazialen Anomalien mittels digitaler Technologie im Tübinger Konzept

Für die Behandlung junger Patienten mit kraniofazialen Anomalien ist die Entwicklung eines digitalen Workflows für das Design von Apparaturen auf Basis von intraoralen Scans die erste Hürde. Um die Sicherheit dieser Patientengruppe zu gewährleisten, werden potenzielle additiv oder subtraktiv gefertigte Materialien getestet und die Genauigkeit in vitro gemessen.

Fully Guided Zygomatic Implant Surgery

INTRODUCTION

Rehabilitating a severely atrophic maxilla is a complex procedure. In case of severe resorption, zygomatic implants are indicated and loading of the implants at the end of the surgery is desirable. We present a new method by means of guided surgery for the placement of zygomatic implants, using specially designed metal templates that should be supported by bone.

METHODS

The treatment planning for completely guided prosthetic rehabilitation of the maxilla with zygomatic implants was digitally performed. A radiographic template was designed for the prosthetic treatment planning. A surgical template was used to replicate the digitally planned steps in vivo.

RESULTS

The procedure ended with the positioning of a custom-made temporary prosthesis. This method can reduce the surgery duration, simplify the procedure, and optimize the outcome. It requires equal cooperation among technicians, prosthodontists, and surgeons. Nineteen out of twenty patients included in the study presented successful implants and prosthesis at the moment of analysis.

CONCLUSIONS

The present approach addressed the needs for zygomatic-implant surgery. The surgical and prosthetic plan, position, emergence, the shape of the implants, the position of the temporary prosthesis, the inter-arch relationships, and surgical templates were designed in a completely virtual environment and performed by the surgeon on stereolithographic models beforehand. Consequently, the surgical procedure was considerably simplified.

The Crucial Role of Plaque Control in Peri-Implant Mucositis Initiation as Opposed to the Role of Systemic Health Condition: A Cross-Sectional Study

Purpose

The aim of this study was to investigate the priority of periodontal plaque as a risk factor compared to other risk factors, namely hypertension and diabetes mellitus type II, regarding the initiation and severity of peri-implant mucositis, eventually reinforcing the importance of plaque control, periodic maintenance and supportive periodontic treatment after implant placement in order to prevent peri-implant diseases.

Patients and Methods

A total of 58 patients (84 implants) were enrolled; each individual implant was considered as a separate sample first, then sampling by patient was also applied, implants were divided into group A: systemically healthy patients and B: patients with hypertension and diabetes mellitus type II, the status of peri-implant tissue was followed after the healing abutment placement, with regard to implant mucosal index (IMI), probing pocket depth (PPD) and bleeding on probing (BOP); when sampling was done by patient, the mean of scores of all examined implants in each patient was taken to represent one sample.

Results

Group A implants showed higher mean scores of PPD (5.2 mm) than group B (4.2 mm) with significance (P = 0.014), and higher mean scores of BOP, group A = 0.71, group B = 0.45 with (P = 0.015); there was no statistical difference with regard to IMI, group A = 1.35, group B = 1.16 with (P = 0.172). Similar results were obtained when the sampling was calculated by patient; PPD: group A (5.31 mm), group B (4.75 mm) and P = 0.008, IMI: group A (1.34), group B (1.16) and P = 0.131, BOP: group A (0.75), group B (0.48) and P = 0.03.

Conclusion

In the absence of proper plaque control, systemic diseases showed no impact on the initiation and severity of peri-implant mucositis when compared to systemically healthy patients.

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Virtual Reality (VR) Simulation and Augmented Reality (AR) Navigation in Orthognathic Surgery: A Case Report

VR and AR technology have gradually developed to the extent that they could help operators in the surgical field. In this study, we present a case of VR simulation for preoperative planning and AR navigation applied to orthognathic surgery. The average difference between the preplanned data and the post-operative results was 3.00 mm, on average, and the standard deviation was 1.44 mm. VR simulation could provide great advantages for 3D medical simulations, with accurate manipulation and immersiveness. AR navigation has great potential in medical application; its advantages include displaying real time augmented 3D models of patients. Moreover, it is easily applied in the surgical field, without complicated 3D simulations or 3D-printed surgical guides.

Bias Evaluation of the Accuracy of Two Extraoral Scanners and an Intraoral Scanner Based on ADA Standards

The spread and application of computer-aided design/computer-aided manufacturing (CAD/CAM) technology have contributed to the rapid development of digitalization in dentistry. The accuracy of scan results is closely related to the devising subsequent treatment plans and outcomes. Professional standards for evaluating scanners are specified in the American National Standard/American Dental Association Standard 132 (ANSI/ADA No. 132). The aims of this study were to use the three samples mentioned in ANSI/ADA No. 132 and evaluate the accuracy and reproducibility of two extraoral scanners and an intraoral scanner based on the inspection standards recommended by ANSI/ADA No. 132. In this study, two trained operators used two extraoral scanners (E4, 3Shape, Denmark & SHINING DS100+, Shining, China) and an intraoral scanner (TRIOS SERIES3, 3Shape, Denmark) to perform 30 scans of each of the three samples at a temperature of 25 ± 2°C and export standard tessellation language files and used reverse engineering software to perform measurements and iterative nearest point matching experiments. The measured values obtained were compared with the reference values measured by a coordinate measuring machine (NC8107, Leader Metrology, USA). We performed a normal distribution test (Shapiro-Wilk test), the nonparametric Kruskal-Wallis test, and an independent-samples t-test to analyze the reproducibility of each scan for different models. The experimental results indicate that the trueness and precision of the two extraoral scanners and the intraoral scanner had a slight mean deviation. The trueness and precision of the three scanners on the curved surface and groove areas are poor. The accuracy and reproducibility of E4 outperformed SHINING and TRIOS. The iterative closest point matching experiment also showed good matching results. The two extraoral scanners and the intraoral scanner in this study can meet the basic clinical requirements in terms of accuracy, and we hope that digital technology will be more widely used in dentistry in the future.

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.

The Morpho-Functional Three-Dimensional Analysis for Zygomatic Implants: A Clinical Tool With Surgical Implications

ABSTRACT

Zygomatic implants (ZIs) have been used successfully for the rehabilitation of jaws with severe atrophy for the past 2 decades. The development of computed tomography, three-dimensional (3D) analysis software, and stereolithographic models has positively impacted the development of preoperative planning. This article describes the protocol developed by the Department of Oral and Maxillofacial Surgery of El Bosque University, Bogotá, Colombia, through 10 years of experience, for the installation of ZIs, covering from the times when the implants were placed through intraoperative guidance, until now, in which drilling guides developed by computer-aided design and computer-aided manufacturing are used, without neglecting in their design multiple factors that must be considered. To date, this protocol for the treatment of patients with atrophic jaws through ZIs includes a detailed clinical examination, in which variables such as bone and dental relationship between the jaws, oral opening and dynamic interaction between soft cervicofacial tissues are considered. It also includes a 3D computed tomography planning for the design and preparation of surgical guides whose insertion patterns must be executable during surgery. Together, clinical and imaging analysis converge in what it has been called morpho-functional 3D planning.

Students' perceptions and attitudes about digital dental technology is associated with their intention to use it

PURPOSE/OBJECTIVES

To investigate factors associated with predoctoral students' intention to use dental technology in future practice using the theory of planned behavior.

METHODS

A comprehensive survey was developed consisting of 29 questions grouped in three main domains: knowledge, perception, and suggestions. After students had completed their digital dentistry didactic courses in 2019, the University of Iowa-College of Dentistry and Dental Clinics D2, D3, and D4 classes completed the survey. The D1 class was excluded because they had not finished their digital dentistry didactic courses. The survey data were tabulated for each class separately to compare trends among classes. Each response was analyzed individually before creating scores for the various subdomains. A linear regression analysis was used to create the final model for the outcome variable (intention to use technology).

RESULTS

The response rate was 95% (n = 232). The mean age of participants was 25.7 years (SD = 2.7). There were significant differences between the classes in their knowledge (p < 0.0001), perceived quality of training (p < 0.0001), and all perceptions related to digital dentistry. Controlling for significant covariates among higher level students, there were significant associations between intention to use dental technology and greater knowledge scores (p = 0.05), attitude (p < 0.0001), subjective social norms (p = 0.02), and perceived control on the future use of technology (p < 0.0001).

CONCLUSIONS

Students may be motivated to use digital technology when they have good knowledge, feel that others are using it or endorsing its use, and perceive that they have control in their future practice.

The optimal orthodontic displacement of clear aligner for mild, moderate and severe periodontal conditions: an in vitro study in a periodontally compromised individual using the finite element model

Background

Pathologic tooth migration (PTM) is a common complication of mild to severe periodontitis and proper orthodontic treatment is helpful to alleviate periodontal diseases. The goal of this study is to explore an optimal orthodontic displacement of clear aligner using a three-dimensional (3D) finite element model (FEM).

Methods

The cone beam computed tomography (CBCT) data of a patient received invisible orthodontics without diabetes and other systemic diseases were collected. Based on the new classification scheme for periodontal diseases in 2017 (stage I: mild periodontitis, [M1]; stage II: moderate periodontitis, [M2]; stage III: severe periodontitis, [M3]), 3D-FEMs of mandible were established using MIMICS 10.0 and ABAQUS 6.5 softwares. The 3D stress distribution diagrams and stress value of the teeth (left lower incisor, left lower central incisor, right lower lateral incisor, and right lower central incisor) under three different periodontal conditions (M1, M2, and M3) with axial inclination 90° and 100° were obtained by ABAQUS 6.5.

Results

The stress of anterior teeth was concentrated in the teeth neck, and became greater when the periodontal condition was worse. The stress value of anterior teeth and the strain at the top of the alveolar crest are greater as the displacement increasing. The stress value of anterior teeth and the strain at the top of the alveolar crest in axial inclination 100° are relatively great compared to those of axial inclination 90°. For patients with excessively inclined anterior teeth (such as 100°), the optimal orthodontic displacement is 0.18 mm. In order to ensure that alveolar ridge crest is not deformed, the displacement is less than 0.18 mm (strain for 0.165 mm), 0.15 mm (strain for 0.167 mm) and 0.10 mm (strain for 0.117 mm) respectively when alveolar bone is normal, resorption 1/3 or 1/3–1/2.

Conclusions

The optimal orthodontic displacement for patients (M1, M2, and M3) with excessively inclined anterior teeth (axial inclination 100°) is 0.18 mm. To avoid the strain at the top of the alveolar crest, the optimal displacements for M1, M2 and M3 periodontal disease patients are less than 0.18 mm, 0.15 mm and 0.10 mm, respectively.

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.

Analysis of Digital Workflow in Implantology

Digital workflow is increasingly accessible in daily dental practice. It has several benefits in implantology, such as the possibility of precise planning, which results in faster and safer surgery and, consequently, reduced prosthetic complications. There are also disadvantages that must be taken into consideration for successful treatment, such as deviations between the planned and placed implant position and intraoral scanning inaccuracies. We report a clinical case in implantology in which digital workflow was used throughout the process, pointing out its facilities and complications in the daily practice of dental surgeons. The patient had grade II mobility and external root resorption of tooth 11. After virtual planning, a surgical guide was fabricated by a CAD/CAM system, with immediate placement of a dental implant using the guided surgery technique. At the end of the osseointegration period, intraoral scanning was performed for fabrication of the final prosthesis also by a CAD/CAM system. After placement, the patient approved the aesthetic and functional results of the implant. We observed advantages such as simplification of clinical steps and safety of the proposed planning, but there were also disadvantages such as the complexity of digital tools, deviations of the placed implant, and inaccuracy in color selection. It was concluded that digital workflow is a reality that can be integrated into daily dental practice, resulting in greater safety, predictability of results, and ease of use in all clinical stages. However, it should be noted that there are still inaccuracies in digital tools and that a steep learning curve is needed in this area, which, if neglected, may lead to unsatisfactory results.

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.

Growth Factors in Oral Tissue Engineering: New Perspectives and Current Therapeutic Options

The present investigation is aimed at systematically analyzing the recent literature about the innovative scaffold involved in the reconstructive surgeries by applying growth factors and tissue engineering. An extensive review of the contemporary literature was conducted according to the PRISMA guidelines by accessing the PubMed, Embase, and Scopus Elsevier databases. Authors performed the English language manuscript research published from 2003 to 2020. A total of 13 relevant studies were included in the present review. The present systematic review included only papers with significant results about correlation between scaffold, molecular features of growth factor, and reconstructive surgeries in oral maxillofacial district. The initial research with filters recorded about 1023 published papers. Beyond reading and considering of suitability, only 42 and then 36 full-text papers were recorded for the revision. All the researches recorded the possibility of using growth factors on rebuilding atrophic jaws. Different growth factors like morphogenetic factors, cytokines, and inflammatory ones and their application over different scaffold materials were recorded. Further investigations should be required in order to state scientific evidence about a clear advantage of applying tissue engineering for therapeutic purpose.

The creation of a virtual dental patient with dynamic occlusion and its application in esthetic dentistry

The application of a virtual dental patient with dynamic occlusion during esthetic restoration in a digital workflow is described. An intraoral scanner, a facial scanner, a jaw motion analyzer, and cone beam computed tomography were used to transfer patient data and construct the virtual dental patient. With the aid of the virtual dental patient, predictability and accuracy can increase throughout treatment, simplifying the clinical evaluation and prosthesis adjustment with improved esthetic outcomes.

Online-based software for guiding immediate implantation to replace a tooth with root resorption in the esthetic zone

This case report describes an alternative approach for the planning of immediate implant placement and provisionalization, which uses a new online dental software that predicts the esthetic outcome.

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.

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.

A new software architecture proposal for an evidence-based Decision Support System in dentistry

BACKGROUND

in dentistry, clinical problems could be resolved using many therapeutic approaches that may results in very different therapies. In order to choose the best option, a good evaluation of therapy long-term survival and success rate is mandatory. The routine use of a decision support analysis software is nowadays limited due to the lack of software's flexibility especially when a variety of possible therapeutic option are present. The aim of this research was to develop a new algorithm model for a Decision Support System software to give diagnosis support in dentistry.

METHODS

Beta tests were designed to study the computer software in different clinical situations based on clinical data. The therapeutic options can be conservative/endodontic or extractive/prosthetic therapies. In two of clinical situation selected could be possible to choose both therapies.

RESULTS

in clinical situations tested, the DDS software correctly identified the several therapeutic options. When multiple treatments were possible the beta test showed an output mask that correctly showed a range of options with their corresponding survival and success rate.

CONCLUSIONS

The software architecture proposed by the authors is technically feasible, can support the clinician choices based on scientific evidence and up-to-date references and gain informed consent based on data easily understandable for the patient.

Anterior Esthetic Rehabilitation of an Alveolar Cleft Using Novel Minimally Invasive Prosthodontic Techniques: A Case Report

Missing lateral incisors are the most frequent dental disorder associated with cleft alveolus. When orthodontic closure of the edentulous space is not possible, more aggressive prosthodontic treatments are required. Contemporary resin-bonded fixed dental prostheses (RBFDPs) represent a promising, time-efficient alternative treatment with fewer biological complications. This clinical report proposes a modified approach to the esthetic rehabilitation of a patient with a complete unilateral cleft lip and palate on the left side and an incomplete cleft lip and alveolar cleft on the right side. Digital diagnostics, treatment planning, and clinical procedures involved in the fabrication of facially bonded RBFDPs are presented. This modified technique enables the concurrent replacement of lateral incisors and correction of the malformed central incisors as well as increasing the retention of the restorations.

A Digital Esthetic Rehabilitation of a Patient with Dentinogenesis Imperfecta Type II: A Clinical Report

A 19‐year‐old female affected by dentinogenesis imperfecta type II (DI‐II), a genetic disease that affects the structural integrity of the dentin, presented with a chief complaint of discolored teeth. For this patient, digital techniques, including digital smile design (DSD), the ARCUSdigma axiograph and computer‐aided design/computer‐aided manufacturing (CAD/CAM), were extensively used in all phases of the rehabilitation process. Compared to traditional analog methods, these digital techniques could reduce the constant confirmation of occlusion, promote communication between clinicians and dental technicians, achieve accurate occlusion with relatively high efficiency, and improve the efficacy of esthetic rehabilitation in the treatment of this patient with DI‐II.

Aesthetic Dentistry, How You Say and How You See: A 500-People Survey on Digital Preview and Color Perception

Purpose

Digital technologies have improved ways to perform aesthetic dentistry in the last few years. The aims of this survey were to investigate the most preferred way to preview the result of an aesthetic dental rehabilitation among a population of dental professionals and laypeople and to compare aesthetic standards of the general population and dentists in terms of the color of teeth for aesthetic dental rehabilitations.

Patients and Methods

A questionnaire was sent to the subjects (dentists and laypeople) during a 1-year period and, together with their demographic data, different ways to preview the result of an aesthetic rehabilitation were submitted, such as digital smile design, dental wax-up and oral explanation. Furthermore, an additional section of the questionnaire investigated the most suitable color for an aesthetic rehabilitation based on the colors of the VITA Scale. Results were statistically analyzed (with Chi-square of independence and Mann–Whitney U-test) highlighting differences of answers based on age groups, educational attainment, gender, and belonging or not to the dental field.

Results

Findings showed that digital smile design (digital preview) is a high-appreciated method for previewing and communicating with patients both by dental professionals and laypeople. Furthermore, lighter colors were found to be more valued by laypeople and significant differences were highlighted between the two populations assessed.

Conclusion

It seems to be viable to use digital preview for dentists and laypeople to improve previewing and communicating ways. It might be advisable to better motivate patients in recognizing aesthetical features and to raise their awareness in preferring more mimetic aesthetic results. Great opportunities are opened up by digital smile design in teaching, learning, and routine practice.

SARS-CoV-2 Persistence: Data Summary up to Q2 2020

The coronavirus pandemic is causing confusion in the world. This confusion also affects the different guidelines adopted by each country. The persistence of Coronavirus, responsible for coronavirus disease 2019 (Covid-19) has been evaluated by different articles, but it is still not well-defined, and the method of diffusion is unclear. The aim of this manuscript is to underline new Coronavirus persistence features on different environments and surfaces. The scientific literature is still poor on this topic and research is mainly focused on therapy and diagnosis, rather than the characteristics of the virus. These data could be an aid to summarize virus features and formulate new guidelines and anti-spread strategies.

The Digital Integrated Workflow in the Aesthetic Management of the Smile: A Case Report

The aesthetic treatment for anterior teeth requires a series of clinical and technical evaluations to obtain a predictable result, following a well-defined operating sequence. Today, the clinical–technical team can use different digital tools in the different steps of the workflow. A preventive assessment, the knowledge of limits, and the possibilities of surgical and prosthetic procedures allow to use these devices. Sharing goals of the treatment with the patient according to their expectations and needs is the key point of the treatment plan. Setting a defined treatment plan avoids invasive procedures. In this clinical case report, a 27-year-old patient affected by Class II div 2 malocclusion with deep bite was treated with a full digital workflow. Previewing the aesthetics was through dedicated software, which shows operators and patients the objectives of the therapy and guides the dental technician in the first phase of the work. The use of digital flows in the prosthetic phases reduces the working time. In this case, it shows the impact of a digital workflow on peri-prosthetic therapy for the aesthetic rehabilitation of the upper central incisors in a young adult.

DSDapp use for multidisciplinary esthetic planning

OBJECTIVES

Digital smile design (DSD) is useful in planning multidisciplinary esthetic treatments. However, DSD requires clinician training and skill to ensure its effective use. The Digital smile design application (DSDapp) was recently developed, to facilitate such planning. The objective of this study was to illustrate the use of the DSDapp for esthetic planning in a clinical case that included periodontal plastic surgery and ceramic laminate veneers.

CLINICAL CONSIDERATIONS

An intraoral digital scan was performed, and a photograph was obtained using an iPad (frontal facial full smile). The images were analyzed using the DSDapp. All reference lines were inserted, and dental shapes predetermined by the app were superimposed on the photographs. A digital diagnostic wax-up was performed considering the plan created in the DSDapp. After 3D printing the wax-up, a mock-up transferred the planning to the oral cavity. Following this, the patient was referred to a periodontist for the periodontal plastic surgery. After the healing period, the teeth were prepared for computer-aided design/computer-aided modeling lithium disilicate ceramic laminate veneers.

CONCLUSIONS

DSDapp use accelerated the initial planning steps. Smile planning can be performed during the clinical session with the patient's active participation. In addition, the DSDapp facilitated better communication within the multidisciplinary team.

CLINICAL SIGNIFICANCE

The DSDapp relies more on intuition than on skill and training to execute the treatment plan. The DSDapp provides immediate feedback to the patient, offering greater predictability and helps monitor the planning through all the clinical stages.

Feasibility of Using a Prosthetic-Based Impression Template to Improve the Trueness and Precision of a Complete Arch Digital Impression on Four and Six Implants: An In Vitro Study

Background: Intraoral scanners (IOSs) in implantology represent a viable approach for single teeth or partial arches. However, when used for complete edentulous arches or long-span edentulous areas, it has been demonstrated that there is a need for improvement of IOS-related techniques. Therefore, the aim of this in vitro study was to assess the trueness and precision of a complete arch digital impression on four and six implants taken with or without a customized, prosthetic-based impression template. Materials and Methods: Two experimental models were prepared, representative of a complete edentulous mandible restored with four and six implants with built-in scan abutments. Models were scanned with (test group, TG) or without (control group, CG) the prosthetic-based impression template. Eight scans were taken for each model. The time needed to take impressions, error, trueness, and precision were evaluated. A statistical analysis was performed. Results: In the case of four implants, the time needed for the impression was 128.7 ± 55.3 s in the TG and 81.0 ± 23.5 s in the CG (p = 0.0416). With six scan abutments, the time was 197.5 ± 26.8 and 110.6 ± 25.2 s in the TG and CG, respectively (p = 0.0000). In the TG, no errors were experienced, while in the CG, 13 impressions were retaken due to incorrect stitching processes. In the four-implant impression, the mean angle deviation was 0.252 ± 0.068° (95% CI 0.021–0.115°) in the CG and 0.134 ± 0.053° (95% CI 0.016–0.090°) in the TG. The difference was statistically significant (p = 0.002). In the six-implant impression, the mean angle deviation was 0.373 ± 0.117° (95% CI 0.036–0.198°) in the CG and 0.100 ± 0.029° (95% CI 0.009–0.049°) in the TG (p = 0.000). In the TG, there were no statistically significant differences in the mean angle deviation within the group (p > 0.05), but there were in the CG. A colorimetric analysis showed higher deviations from the original model for the six-implant impression without a prosthetic template. Conclusions: Although all of the impressions exhibited deviation from the original model in the range of clinical acceptability, the prosthetic-based impression template significantly improved the trueness and precision of complete edentulous arches rehabilitated with four or six implants, making the complete arch digital impression more predictable.

Biological and Chemo-Physical Features of Denture Resins

In the dental field, the study of materials has always been the basis of the clinical practice. Over the years, with the evolution of materials, it has been possible to produce safe and predictable prosthetic devices, with ever better aesthetic features, biocompatibility and patient satisfaction. This review briefly analyzes the features of dental resin materials to underline the biological, microbiological and chemo-physical characteristics. The main aim of prosthodontics is to rehabilitate patients and therefore improve their quality of life. Dental resins are the main materials used for the production of dentures. Once solidified, these polymers have different mechanical or surface characteristics. The results of the literature on these characteristics were analyzed and some new brand dental resins, known as modern resin, were subsequently evaluated. The new materials are undoubtedly a step forward in the creation of dental prostheses, and also in all subsequent maintenance phases. This review shows how changing the chemical structure of the resins could have microbiological influences on the growth and management of the biofilm, and also physical influences in terms of its mechanical characteristics. The development of new materials is a constant goal in dentistry in order to obtain increasingly predictable rehabilitations.

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.

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”.

The Role of Digital Devices in Dentistry: Clinical Trends and Scientific Evidences

In recent years, digital technologies have significantlychanged the clinical approach to medicine and dentistry. Innovative operative techniques and restorative materials have paved the way to a significant active boost towards full digital workflows. Particularly, novel dental materials offer undeniable advantages such as optimal mechanical resistance, excellent esthetic and optical properties, and reliable accuracy and precision, widening the clinical scenario and allowing for innovative and less invasive restorative solutions.

Automated integration of facial and intra-oral images of anterior teeth

BACKGROUND AND OBJECTIVE

Digital smile design is the technique that dentists use to analyze, design, and visualize therapeutic results on a computing workstation prior to actual treatment. Despite it being a crucial step in digital smile design, the process of labeling and integrating the information in facial and intra-oral images is laborious. Therefore, this study aims to develop an automated photo integrating system to facilitate this process.

METHODS

The teeth in intra-oral images were distinguished by their curvature and finely segmented using an active contour model. The facial keypoints were detected by a sophisticated facial landmark detector algorithm; these keypoints were then overlaid on the corresponding intra-oral image by extracting the contour of the teeth in the facial and intra-oral photographs. With this system, the tooth width-to-height ratios, smile line, and facial midline were automatically marked in the intra-oral image. The accuracy of the proposed segmentation algorithm was evaluated by applying it to 50 images with 274 maxillary anterior teeth.

RESULTS

The proposed algorithm recognized 96.0% (263/274) of teeth in our selected image set. The results were then compared to those obtained by applying manual segmentation to the remaining 263 recognized teeth. With a 95% confidence interval, a Jaccard index of 0.928 ± 0.081, average distance of 0.128 ± 0.109 mm, and Hausdorff distance between the results and ground truth of 0.461 ± 0.495 mm were achieved.

CONCLUSIONS

The results of this study show that the proposed automated system can eliminate the need for dentists to employ a laborious image integration process. It also has the potential for broad applicability in the field of dentistry.

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.

Guided Periodontal Surgery: Association of Digital Workflow and Piezosurgery for the Correction of a Gummy Smile

Digital flow has become a part of currently practiced dentistry. Virtual planning ensures predictable aesthetic and functional rehabilitation, painless postoperative recovery, and better communication with patients, thus meeting their expectations. The purpose of this case report is to demonstrate the digital planning for the correction of a gummy smile with a personalized preparation using a piezoelectric surgical guide (PerioGuide) for gingival contouring and flapless osteotomy. The guide was designed using Nemo Studio software, based on the patient's facial aesthetic analysis, through photos, videos, and facial scanning. These images were aligned with the scan and placed over the cone beam computed gingival tomography for prediction of results, based not only on the distance from the cementoenamel junction to the bone crest but also on the best gingival margin contour according to virtual aesthetic planning. Digital planning, combined with the use of a piezoelectric device, allows for a flapless guided surgical technique for gingival contouring and osteotomy. As a result, the surgical procedure is safer, faster, and more predictable with better postoperative outcomes.

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.

3D-printed Surgical Training Model Based on Real Patient Situations for Dental Education

Background: Most simulation models used at university dental clinics are typodonts. Usually, models show idealized eugnathic situations, which are rarely encountered in everyday practice. The aim of this study was to use 3D printing technology to manufacture individualized surgical training models for root tip resection (apicoectomy) on the basis of real patient data and to compare their suitability for dental education against a commercial typodont model. Methods: The training model was designed using CAD/CAM (computer-aided design/computer-aided manufacturing) technology. The printer used to manufacture the models employed the PolyJet technique. Dental students, about one year before their final examinations, acted as test persons and evaluated the simulation models on a visual analogue scale (VAS) with four questions (Q1-Q4). Results: A training model for root tip resection was constructed and printed employing two different materials (hard and soft) to differentiate anatomical structures within the model. The exercise was rated by 35 participants for the typodont model and 33 students for the 3D-printed model. Wilcoxon rank sum tests were carried out to identify differences in the assessments of the two model types. The alternative hypothesis for each test was: "The rating for the typodont model is higher than that for the 3D-printed model". As the p-values reveal, the alternative hypothesis has to be rejected in all cases. For both models, the gingiva mask was criticized. Conclusions: Individual 3D-printed surgical training models based on real patient data offer a realistic alternative to industrially manufactured typodont models. However, there is still room for improvement with respect to the gingiva mask for learning surgical incision and flap formation.

Effect of A Rapid-Cooling Protocol on the Optical and Mechanical Properties of Dental Monolithic Zirconia Containing 3-5 mol% Y2O3

Many attempts have been made to improve the translucency of zirconia in dentistry. The purpose of this study was to evaluate the effect of a rapid-cooling heat treatment on the optical and mechanical properties of dental monolithic zirconia. Zirconia containing 3, 4, and 5 mol% Y₂O₃ were sintered, sectioned, and polished. The specimens were rapidly cooled from high temperature inducing a diffusionless cubic-to-metastable tetragonal (t') phase transformation. The changes in L^*a^*b^* color coordinates, translucency parameter (TP), and total transmittance (T%) were measured. Three-point bending strength, Vickers hardness, and indentation fracture toughness tests were performed. Quantitative phase analyses were carried out by X-ray diffraction with Rietveld refinement. Scanning electron microscopy (SEM) images were obtained. With increasing Y₂O₃ contents, TP and T% values increased while strength and toughness decreased. The Rietveld analysis showed that the amount of t'-phase increased after rapid-cooling and annealed 5Y-partially stabilized zirconia (PSZ) contained the highest amount of t'-phase (64.4 wt%). Rapid-cooling improved translucency but the translucency of annealed 5Y-PSZ did not approach that of lithium disilicate glass-ceramic. Rapid-cooling decreased flexural strength significantly, being 306.1 ± 61.8 MPa for annealed 5Y-PSZ. SEM revealed that grains tended to get larger after rapid-cooling. A rapid-cooling treatment can produce t'-phase which can contribute to an increase in translucency but has a negative effect on the mechanical properties of zirconia.