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13 pages, 7576 KiB

Open AccessArticle

Five Numerical Methods to Assess the Ischemic Risks in Dental Pulp and Neuro-Vascular Bundle Under Orthodontic Movements in Intact Periodontium In Vitro

by Radu-Andrei Moga, Cristian Doru Olteanu and Ada Gabriela Delean

Dent. J. 2025, 13(1), 15; https://doi.org/10.3390/dj13010015 - 27 Dec 2024

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Abstract

Background/Objectives: Dental pulp and its neuro-vascular bundle (NVB) are among the least studied dental tissues. This study identified the best method for evaluating ischemic risks in the dental pulp and NVB of healthy lower premolars under orthodontic forces and in intact periodontium. [...] Read more.

Background/Objectives: Dental pulp and its neuro-vascular bundle (NVB) are among the least studied dental tissues. This study identified the best method for evaluating ischemic risks in the dental pulp and NVB of healthy lower premolars under orthodontic forces and in intact periodontium. Methods: Nine 3D models of the second lower premolar were reconstructed based on the CBCT scans from nine patients. Nine patients (CBCT scan) were subjected to 3 N of intrusion, extrusion, rotation, tipping, and translation. Five numerical methods, Tresca, von Mises (VM), Maximum and Minimum Principal, and hydrostatic pressure were used to biomechanically assess (totaling 225 simulations) the color-coded stress distribution in pulp and NVB. The results (both qualitative and quantitative) were correlated with the physiological maximum hydrostatic pressure (MHP) and known tissular biomechanical behavior. Results: All five methods displayed quantitative amounts of stress lower than MHP and did not seem to induce any ischemic risks for the NVB and pulp of healthy intact premolars. Among the five movements, rotation seemed the most stressful, while translation was the least stressful. The NVB displayed higher amounts of stress and tissular deformations than the pulp, seeming to be more exposed to ischemic risks. Higher tissular deformations are visible in NVB during intrusion and extrusion, while pulpal coronal stress is visible only during translation. Only the VM and Tresca methods showed a constant stress display pattern for all five movements. The other three methods displayed various inconsistencies related to the stress distribution pattern. Conclusions: Only the Tresca and VM methods can provide correct qualitative and quantitative data for the analysis of dental pulp and NVB. The other three methods are not suitable for the study of the pulp and NVB. Full article

(This article belongs to the Special Issue New Trends in Digital Dentistry)

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10 pages, 3175 KiB

Open AccessArticle

Effects of Different Crystallization Protocols on Marginal Gap of Lithium Disilicate Single Crowns: SEM Analysis

by Alon Shadur, Joseph Nissan, Diva Lugassy, Ariana Umansky, Eran Zenziper and Gil Ben-Izhack

Dent. J. 2024, 12(12), 416; https://doi.org/10.3390/dj12120416 - 18 Dec 2024

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Abstract

Objective: In everyday dentistry, lithium disilicate is a valid option for single-fix partial dentures, and this material crystallization process is available with two protocols: long and short. This study’s aim was to assess the effects of these two different crystallization protocols, long and [...] Read more.

Objective: In everyday dentistry, lithium disilicate is a valid option for single-fix partial dentures, and this material crystallization process is available with two protocols: long and short. This study’s aim was to assess the effects of these two different crystallization protocols, long and short, on the marginal gap of lithium disilicate single crowns. Methods: A total of 24 abutment plastic teeth were scanned using an intra-oral scanner. For each plastic tooth, an identical pair of lithium disilicate crowns was milled (a total of 48 crowns) by a four-axis machine. Each paired sample was categorized into two groups: long crystallization (24 crowns) and short crystallization (24 crowns). To assess precision, each unit’s marginal gap (including abutments and crowns) was meticulously measured at four specified regions using a scanning electron microscope. A Kolmogorov–Smirnov test performed on the study variables indicated a normal distribution (p > 0.05), and it was followed by independent t-tests (α = 0.05). Results: For the long crystallization group, the mean total marginal gap values were 42.91 ± 9.67 μm, and for the short crystallization group, the values were 43.25 ± 8.14 μm, with no significant difference between the groups (p = 0.894). In addition, no significant differences were found between the groups regarding the mean marginal gap measurements for all four surfaces (distal (p = 0.310), mesial (p = 0.732), palatal (p = 0.655), and buccal (p = 0.535)). Conclusions: Both the long and short crystallization methods used for lithium disilicate single crowns demonstrated marginal gap values of less than 120 μm, which are within the clinically acceptable range, with no significant differences across any parameters between the two groups. Regarding the marginal gap value, it is recommended to use the short crystallization protocol as it is more time-efficient. Full article

(This article belongs to the Special Issue New Trends in Digital Dentistry)

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17 pages, 2636 KiB

Open AccessArticle

Bilateral Symmetry in the Aesthetic Area Achieved by Digital Smile Design on 3D Virtual Patient and Conventional Diagnostic Wax-Up—A Comparative Study

by Maria Hristozova, Mariya Dimitrova and Stefan Zlatev

Dent. J. 2024, 12(12), 373; https://doi.org/10.3390/dj12120373 - 21 Nov 2024

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Abstract

Background: Digital diagnostic waxing is a contemporary alternative to the conventional wax-up method. This study aims to evaluate the impact of both techniques on the perceived frontal symmetry in aesthetic treatment planning. Dental symmetry significantly influences smile perception and, consequently, the acceptance [...] Read more.

Background: Digital diagnostic waxing is a contemporary alternative to the conventional wax-up method. This study aims to evaluate the impact of both techniques on the perceived frontal symmetry in aesthetic treatment planning. Dental symmetry significantly influences smile perception and, consequently, the acceptance of treatment outcomes, highlighting its clinical importance in restorative dentistry. Materials and Methods: A total of 100 teeth were measured, with 50 (n = 50) waxed up using traditional modeling techniques and 50 using a face-guided digital approach. The study involved ten patients requiring fixed restorations in the aesthetic zone. Both digital and conventional wax-ups were performed for each participant. Gypsum models with wax-ups were digitized and superimposed onto the digital diagnostic design using 3Shape Dental Designer Studio software, Version 2023 (3Shape, Copenhagen, Denmark). Screenshots of the frontal view were captured, and the width of each morphologically altered tooth was measured using ImageJ software Version 1.54 (National Institutes of Health, Bethesda, MD, USA). Results: The results indicated no statistically significant difference in symmetry between the right and left sides achieved by the two diagnostic approaches (t-value = −1.89, p-value = 0.07). The perceived symmetry of morphologically modified frontal teeth, as achieved by digital and conventional waxing, was found to be comparable. Conclusions: Digital diagnostic planning is validated as a reliable alternative to the conventional wax-up method, offering comparable accuracy in achieving dental symmetry while potentially enhancing efficiency and precision in the aesthetic treatment planning process. This result underscores the potential of digital technologies to streamline clinical workflows and improve patient outcomes. Clinically, achieving symmetry in the aesthetic zone is crucial for patient satisfaction and acceptance of restorative procedures, emphasizing the need for continued integration of digital tools in dental practice. Full article

(This article belongs to the Special Issue New Trends in Digital Dentistry)

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16 pages, 3011 KiB

Open AccessArticle

An In Vivo Comparison of Trueness and Precision of Two Novel Methods for Improving Edentulous Full Arch Implant Scanning Accuracy: A Pilot Study

by Adam Brian Nulty

Dent. J. 2024, 12(11), 367; https://doi.org/10.3390/dj12110367 - 18 Nov 2024

Cited by 2 | Viewed by 2843

Abstract

Background: This retrospective in vivo study evaluated the trueness and precision of two digital intraoral scanners—Dentsply Sirona Primescan and Medit i900—, both with and without two variants of the novel Scan Ladder aids, and compared their performance to a new intraoral photogrammetry scanner [...] Read more.

Background: This retrospective in vivo study evaluated the trueness and precision of two digital intraoral scanners—Dentsply Sirona Primescan and Medit i900—, both with and without two variants of the novel Scan Ladder aids, and compared their performance to a new intraoral photogrammetry scanner (Shining 3D Elite). Methods: Data from ten edentulous patients, previously collected during routine clinical treatment, were analyzed using a master STL generated from traditional impression casts as the reference. A custom positional change calculator and comprehensive statistical analysis were used to assess scanner accuracy. Results: The findings demonstrated that the use of the Scan Ladder significantly enhanced the overall accuracy of both intraoral scanners, showing no statistically significant differences when compared to the intraoral photogrammetry system. Conclusions: These results indicate that the Scan Ladder improves the performance of conventional intraoral scanners and suggests that the Shining 3D Elite intraoral photogrammetry scanner is a reliable alternative to extraoral photogrammetry for edentulous cases. Further research, with a larger and more diverse cohort, is warranted to validate and expand upon these findings. Full article

(This article belongs to the Special Issue New Trends in Digital Dentistry)

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18 pages, 2199 KiB

Open AccessFeature PaperArticle

Efficacy of Virtual Preparation Simulators Compared to Traditional Preparations on Phantom Heads

by Lea Stoilov, Fabian Stephan, Helmut Stark, Norbert Enkling, Dominik Kraus and Milan Stoilov

Dent. J. 2024, 12(8), 259; https://doi.org/10.3390/dj12080259 - 14 Aug 2024

Cited by 1 | Viewed by 1768

Abstract

Background: Virtual simulators are increasingly being introduced in dental education. This study investigates whether virtual simulators offer comparable or superior educational efficacy when compared to traditional phantom simulators. Materials and Methods: Participants were randomly allocated into groups: Virtual Preparation (SIM; n = 30) [...] Read more.

Background: Virtual simulators are increasingly being introduced in dental education. This study investigates whether virtual simulators offer comparable or superior educational efficacy when compared to traditional phantom simulators. Materials and Methods: Participants were randomly allocated into groups: Virtual Preparation (SIM; n = 30) and Traditional Preparation (FRA; n = 30). Students were tasked with preparing tooth 36 for a full-cast crown during free practice for four days. Faculty staff provided feedback to both groups. Examinations were administered and graded by three examiners (preclinical and clinical consultants and a dental surgery consultant). Additionally, a survey was conducted to assess each training concept. Results: The FRA group achieved significantly better grades in the preparation exam evaluations by all three examiners, compared to the SIM group. Interrater reliability showed only moderate agreement, with the clinical examiner giving better grades than the other two. The questionnaire results indicate that while participants managed with the virtual system, they preferred the analog system for exams and patient preparation. Conclusion: Virtual simulators do not seem to be as good when it comes to practicing for a preparation exam or clinical preparation, especially for unexperienced students. However, they still appear to be useful as an additional tool for introducing students to the topic of preparation. Full article

(This article belongs to the Special Issue New Trends in Digital Dentistry)

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22 pages, 22805 KiB

Open AccessArticle

Trabecular Bone Component Assessment under Orthodontic Loads and Movements during Periodontal Breakdown—A Finite Elements Analysis

by Radu-Andrei Moga, Cristian Doru Olteanu and Ada Gabriela Delean

Dent. J. 2024, 12(6), 190; https://doi.org/10.3390/dj12060190 - 20 Jun 2024

Viewed by 1241

Abstract

This numerical analysis, by employing Tresca and Von Mises failure criteria, assessed the biomechanical behavior of a trabecular bone component subjected to 0.6, 1.2, and 2.4 N orthodontic forces under five movements (intrusion, extrusion, tipping, rotation, and translation) and during a gradual horizontal [...] Read more.

This numerical analysis, by employing Tresca and Von Mises failure criteria, assessed the biomechanical behavior of a trabecular bone component subjected to 0.6, 1.2, and 2.4 N orthodontic forces under five movements (intrusion, extrusion, tipping, rotation, and translation) and during a gradual horizontal periodontal breakdown (0–8 mm). Additionally, they assessed the changes produced by bone loss, and the ischemic and resorptive risks. The analysis employed eighty-one models of nine patients in 405 simulations. Both failure criteria showed similar qualitative results, with Tresca being quantitatively higher by 1.09–1.21. No qualitative differences were seen between the three orthodontic loads. Quantitatively, a doubling (1.2 N) and quadrupling (2.4 N) were visible when compared to 0.6 N. Rotation and translation followed by tipping are the most stressful, especially for a reduced periodontium, prone to higher ischemic and resorptive risks. In an intact periodontium, 1.2 N can be safely applied but only in a reduced periodontium for extrusion and intrusion. More than 0.6 N is prone to increasing ischemic and resorptive risks for the other three movements. In an intact periodontium, stress spreads in the entire trabecular structure. In a reduced periodontium, stress concentrates (after a 4 mm loss—marker for the stress change distribution) and increases around the cervical third of the remaining alveolar socket. Full article

(This article belongs to the Special Issue New Trends in Digital Dentistry)

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9 pages, 4649 KiB

Open AccessTechnical Note

MAMA—Mandibular Advancement Magnetic Appliance: A Digital Workflow and a CAD–CAM Development of a New Mandibular Advancement Device for the Treatment of Obstructive Sleep Apnea Syndrome

by Riccardo Nucera, Enrico Nastro Siniscalchi, Giancarlo Consolo, Luigi Calabrese, Daniela Caccamo, Angela Mirea Bellocchio and Marco Portelli

Dent. J. 2025, 13(3), 104; https://doi.org/10.3390/dj13030104 - 27 Feb 2025

Viewed by 453

Abstract

Background/Objectives: Mandibular advancing devices (MADs) are removable intraoral apparatuses to use during sleep that modify the spatial position of the mandible, increasing airway patency and improving respiratory function at night in patients with obstructive sleep apnea syndrome (OSAS). Methods: In this work, a [...] Read more.

Background/Objectives: Mandibular advancing devices (MADs) are removable intraoral apparatuses to use during sleep that modify the spatial position of the mandible, increasing airway patency and improving respiratory function at night in patients with obstructive sleep apnea syndrome (OSAS). Methods: In this work, a new mandibular advancement device useful for mild-to-moderate OSAS patients is presented. It is developed through a CAD–CAM process and involves a passive propulsion of the mandible thanks to the attraction of rare-earth magnets positioned in the thickness of two thermally molded PET-G devices. The use of a PET-G device compared to traditional resin ones offers several clinical advantages related to the innovative characteristics of this polymer, which allows the fabrication of thinner devices, with high resistance to fluid corrosion, resulting in less bulk inside the oral cavity. Results: The innovative feature of the device proposed by the authors is that mandibular propulsion induced by the attraction of the magnetic jigs is not affected by a patient’s mandibular posture during sleep. Conclusions: The original apparatus proposed by the authors determines a mesializing movement of the jaw through a different mechanism to traditional MADs and presents the great advantage of a digital and CAD–CAD workflow that can be developed directly by the clinicians in the practice. Full article

(This article belongs to the Special Issue New Trends in Digital Dentistry)

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12 pages, 8463 KiB

Open AccessCase Report

Application of CAD-CAM 3D Technology in Designing a Molar Distalization Device with Skeletal Anchorage: A Case Report

by Martina Mezio, Alessandra Putrino, Ersilia Barbato, Stefano Pandolfi and Michele Cassetta

Dent. J. 2024, 12(12), 417; https://doi.org/10.3390/dj12120417 - 18 Dec 2024

Cited by 1 | Viewed by 945

Abstract

Objectives: Mandibular molar distalization is a complex orthodontic movement due to anatomic and biomechanical limitations. The opportunity to use a custom-made appliance with skeletal anchorage should be an advantageous alternative to traditional solutions: multiple extractions, interproximal reductions, vestibular inclination of incisal group. Methods [...] Read more.

Objectives: Mandibular molar distalization is a complex orthodontic movement due to anatomic and biomechanical limitations. The opportunity to use a custom-made appliance with skeletal anchorage should be an advantageous alternative to traditional solutions: multiple extractions, interproximal reductions, vestibular inclination of incisal group. Methods: A 14-year-old female patient with Class II malocclusion and ectopic upper and lower canines was treated in the lower arch with a custom-made appliance anchored on a mini-screw in the right buccal-shelf where the ectopy and crowding was severe. The miniscrew was connected to a rigid arm with a rail equipped with a coil that activated promoted the distalization of first and second molars bonded with metallic bands. Results: After 8 months of treatment with activations repeated every 4 weeks, an effective distalization has been reached. Conclusions: Mandibular molars’ distalization is a challenging orthodontic result to achieve. When the need to obtain space cannot be beneficially obtained with conventional approaches, and distalization of the lower molars could be desirable, a custom distalization device with skeletal anchorage and biomechanics based on a pressed coil sliding on a rigid arm is an efficient solution. Full article

(This article belongs to the Special Issue New Trends in Digital Dentistry)

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