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12 pages, 15256 KiB

Open AccessArticle

A Microcomputed Tomographic Evaluation of Root Canal Morphology of Maxillary Second Premolars in a Pakistani Cohort

by Mazen F. Alkahtany, Saqib Ali, Abdul Khabeer, Shafqat A. Shah, Khalid H. Almadi, Abdulaziz Abdulwahed, Imran Farooq, Fahim Vohra and Tariq Abduljabbar

Appl. Sci. 2021, 11(11), 5086; https://doi.org/10.3390/app11115086 - 31 May 2021

Cited by 3 | Viewed by 3434

Abstract

This study aimed to investigate variations in the root canal morphology of maxillary second premolar (MSP) teeth using microcomputed tomography (micro-CT). Sixty (N = 60) human extracted MSPs were collected and prepared for micro-CT scanning. The duration for scanning a single sample ranged [...] Read more.

This study aimed to investigate variations in the root canal morphology of maxillary second premolar (MSP) teeth using microcomputed tomography (micro-CT). Sixty (N = 60) human extracted MSPs were collected and prepared for micro-CT scanning. The duration for scanning a single sample ranged between 30 and 40 min and a three-dimensional (3-D) image was obtained for all the MSPs. The images were evaluated by a single observer who recorded the canal morphology type, number of roots, canal orifices, apical foramina(s), apical delta(s), and accessory canals. The root canal configuration was categorized in agreement with Vertucci’s classification, and any configuration not in agreement with Vertucci’s classification was reported as an “additional canal configuration”. Descriptive statistics (such as mean percentages) were calculated using SPSS software. The most common types agreeing with Vertucci’s classification (in order of highest to lowest incidence) were types I, III, V, VII, II, and VI. The teeth also exhibited four additional configurations that were different from Vertucci’s classification: types 2-3, 1-2-3, 2-1-2-1, and 1-2-1-3. A single root was found in 96.7% and the majority of the samples demonstrated two canals (73.3%). Further, 80% of the teeth showed one canal orifice. The number of apical foramina’s in the teeth was variable, with 56.7% having solitary apical foramen. The accessory canal was found in 33.3%, and apical delta was found in only 20% of the samples. Variable morphology of the MSPs was detected in our study. The canal configuration most prevalent was type 1; however, the results also revealed some additional canal types. Full article

(This article belongs to the Special Issue Applied Simulation and Experiment Research in Dentistry)

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17 pages, 5694 KiB

Open AccessArticle

Computerized Generation and Finite Element Stress Analysis of Endodontic Rotary Files

by Victor Roda-Casanova, Álvaro Zubizarreta-Macho, Francisco Sanchez-Marin, Óscar Alonso Ezpeleta, Alberto Albaladejo Martínez and Agustín Galparsoro Catalán

Appl. Sci. 2021, 11(10), 4329; https://doi.org/10.3390/app11104329 - 11 May 2021

Cited by 12 | Viewed by 3088

Abstract

Introduction: The finite element method has been extensively used to analyze the mechanical behavior of endodontic rotary files under bending and torsional conditions. This methodology requires elevated computer-aided design skills to reproduce the geometry of the endodontic file, and also mathematical knowledge to [...] Read more.

Introduction: The finite element method has been extensively used to analyze the mechanical behavior of endodontic rotary files under bending and torsional conditions. This methodology requires elevated computer-aided design skills to reproduce the geometry of the endodontic file, and also mathematical knowledge to perform the finite element analysis. In this study, an automated procedure is proposed for the computerized generation and finite element analysis of endodontic rotary files under bending and torsional conditions. Methods: An endodontic rotary file with a

25 mm

total length,

0.25 mm

at the tip,

1.20 mm

at

16 mm

from the tip,

2 mm

pitch and squared cross section was generated using the proposed procedure and submitted for analysis under bending and torsional conditions by clamping the last

3 mm

of the endodontic rotary file and applying a transverse load of

0.1 N

and a torsional moment of

0.3 N \cdot cm

. Results: The results of the finite element analyses showed a maximum von Mises stress of

398 MPa

resulting from the bending analysis and a maximum von Mises stress of

843 MPa

resulting from the torsional analysis, both of which are next to the encastre point. Conclusions: The automated procedure allows an accurate description of the geometry of the endodontic file to be obtained based on its design parameters as well as a finite element model of the endodontic file from the previously generated geometry. Full article

(This article belongs to the Special Issue Applied Simulation and Experiment Research in Dentistry)

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10 pages, 12244 KiB

Open AccessArticle

Functional Evaluation of a Novel Multi-Axial Alveolar Distractor—Preliminary In Vivo Animal Study

by Cheng-Hsien Wu, Kun-Chun Chen, Yang-Sung Lin, Yuan-Chih Liu and Chun-Li Lin

Appl. Sci. 2021, 11(4), 1898; https://doi.org/10.3390/app11041898 - 22 Feb 2021

Viewed by 2030

Abstract

This study evaluates the biomechanical performance of a new multi-axial alveolar distractor using an animal study. The multi-axial alveolar distractor is designed with a ball and socket joint mechanism that can rotate up to 60° toward the buccal/lingual and mesial/distal sides intra-operatively to [...] Read more.

This study evaluates the biomechanical performance of a new multi-axial alveolar distractor using an animal study. The multi-axial alveolar distractor is designed with a ball and socket joint mechanism that can rotate up to 60° toward the buccal/lingual and mesial/distal sides intra-operatively to achieve vector control. The transport segment can be moved through activating the transport screw with 0.25 pitch, allowing 13 mm in distraction height. This distractor was fixed at the right angulus mandibular of experimental rabbits and adjusted 15° toward the mesial side and 25° toward the buccal side as Group TMB (toward mesial-buccal) (n = 3), and 15° toward the mesial side as Group TM (toward mesial) (n = 3). Group TC (control) was the control group. The distractors were activated 1 mm/day for 13 days. Living bone growth was observed at various periods. The total bone growth length at the angulus region and buccal side distraction thickness after distraction were calculated. The variations in bone growth geometric shape at the mandible angulus were also recorded. Fracture testing was performed to understand the variations in the mechanical strength between the distracted and intact bone specimens. The digital radiography results showed that the osteotomy areas at the mandible angulus were healed and the bone growth completed after surgery. The average bone growth length of Group TMB was 17.68 mm. This was greater than that of Group TM at 14.79 mm. The corresponding buccal side distractor thicknesses for Group TMB and TM after distraction were 5.12 ± 0.52 mm and 3.32 ± 0.37 mm, respectively. The tensile strengths of the bone specimens after distraction of Groups TMB, TM and TC were 172.13 N, 119.27 N and 304.24 N, respectively, and the percentage of distraction bone tensile strength to normal bone was 57% and 39% for Groups TMB and TM, respectively. This study concluded that this new multi-axial alveolar bone distractor can drive bones to grow in accordance with the direction/angle of the distraction plan. The bone growth healed gradually and presented insufficient mechanical strength. Full article

(This article belongs to the Special Issue Applied Simulation and Experiment Research in Dentistry)

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10 pages, 2119 KiB

Open AccessArticle

Novel Digital Technique to Analyze the Influence of the Operator Experience on the Accuracy of the Orthodontic Micro-Screws Placement

by María Bufalá Pérez, Miriam O’Connor Esteban, Álvaro Zubizarreta-Macho, Elena Riad Deglow, Sofía Hernández Montero, Francesc Abella Sans and Alberto Albaladejo Martínez

Appl. Sci. 2021, 11(1), 400; https://doi.org/10.3390/app11010400 - 4 Jan 2021

Cited by 4 | Viewed by 2130

Abstract

To analyze the influence of the operator experience on the accuracy of orthodontic self-tapping micro-screws placement, a total of 60 orthodontic self-tapping micro-screws were randomly distributed into two study groups: Group A. Orthodontic micro-screws placement by an orthodontist with 10 years of experience [...] Read more.

To analyze the influence of the operator experience on the accuracy of orthodontic self-tapping micro-screws placement, a total of 60 orthodontic self-tapping micro-screws were randomly distributed into two study groups: Group A. Orthodontic micro-screws placement by an orthodontist with 10 years of experience (n = 30); and B. Orthodontic micro-screws placement by an orthodontist student without experience (n = 30). Cone-beam computed tomography scans and intraoral scans were performed before and after the orthodontic self-tapping micro-screws placement and uploaded in 3D implant-planning software to analyze the deviation angle and the horizontal deviation measured at the coronal entry point and apical endpoint between orthodontic micro-screws planned and performed. In addition, intraoperative complications such as root perforations after orthodontic self-tapping micro-screws placement and fracture of the orthodontic self-tapping micro-screws during their placement were also analyzed. The paired t-test revealed statistically significant differences at the apical endpoint (p = 0.004) of planned and performed orthodontic self-tapping micro-screws between the orthodontist with 10 years of experience and the orthodontist student without experience. However, the paired t-test revealed no statistically significant differences at the coronal entry point (p = 0.220) and angular deviations (p = 0.602) of planned and performed orthodontic self-tapping micro-screws between the orthodontist with 10 years of experience and the orthodontic student without experience. Furthermore, five root perforations were observed in the no experience study group and three orthodontic self-tapping micro-screws were fractured in each study group. In conclusion, the results show that the greater experience of the operator influences the accuracy of orthodontic micro-screws placement, resulting in less intraoperative complications. Full article

(This article belongs to the Special Issue Applied Simulation and Experiment Research in Dentistry)

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10 pages, 6420 KiB

Open AccessArticle

A Full Digital Workflow to Design and Mill a Splint for a Patient with Temporomandibular Joint Disorder

by Alessandro Nota, Alexander N. Ryakhovsky, Floriana Bosco and Simona Tecco

Appl. Sci. 2021, 11(1), 372; https://doi.org/10.3390/app11010372 - 2 Jan 2021

Cited by 12 | Viewed by 3392

Abstract

In the rehabilitation of a patient with loss of vertical dimension, repositioning of the condyle may be crucial to avoid loading on the retrodiscal area of the temporomandibular joint (TMJ). However, establishing a new position of the condyle within the glenoid cavity is [...] Read more.

In the rehabilitation of a patient with loss of vertical dimension, repositioning of the condyle may be crucial to avoid loading on the retrodiscal area of the temporomandibular joint (TMJ). However, establishing a new position of the condyle within the glenoid cavity is not a simple procedure, and several indications exist in the literature. Digital techniques and 3D visualization using cone beam computed tomography (CBCT) can help. In this clinical case, the procedure for the repositioning of the condyle is described on the basis of the restoration of the normal widths of the intra-articular spaces using a recently introduced software (Avantis3D). After the end of the rehabilitation with the splint, a second examination confirmed the accuracy of the repositioning with this full digital procedure which represents, in selected cases, a useful choice. Full article

(This article belongs to the Special Issue Applied Simulation and Experiment Research in Dentistry)

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7 pages, 1539 KiB

Open AccessArticle

Impact of the Application of Computer-Based 3D Simulation on Acquisition of Knowledge of Guidance of Mandibular Movement

by Hai Yen Mai, Hang-Nga Mai, Hyun-Wook Woo and Du-Hyeong Lee

Appl. Sci. 2021, 11(1), 60; https://doi.org/10.3390/app11010060 - 23 Dec 2020

Cited by 6 | Viewed by 1837

Abstract

Recently, computer-aided three-dimensional (3D) simulation has expanded to modern education. This study aims to investigate the effects of 3D computer simulation on the learning and self-assessment of the guidance of the mandibular movement. Sixty second-grade dental students were randomly distributed into three groups [...] Read more.

Recently, computer-aided three-dimensional (3D) simulation has expanded to modern education. This study aims to investigate the effects of 3D computer simulation on the learning and self-assessment of the guidance of the mandibular movement. Sixty second-grade dental students were randomly distributed into three groups in an occlusion class. Various teaching protocols were used for each group. Students in the first group (lecture (L)) were taught exclusively through a textbook and two-dimensional illustrations. The conventional lecture method followed by computer-aided 3D simulation was applied to the second group (lecture-to-simulation (LtS)). Lastly, students in the third group (lecture with simulation (LwS)) were simultaneously taught using the conventional lecture and computer-aided 3D simulation methods. After teaching each group, a paper-based examination was conducted; actual and expected scores were obtained on the same day as the occlusal class. Analyses of variance with Tukey’s post-hoc analysis were used to compare the teaching protocols, whereas the independent t test was used for comparing between actual and expected scores (α = 0.05). The LwS group exhibited significantly higher actual and student-expected scores than the L and LtS groups (p < 0.001). The expected score was significantly lower than the actual score in the L group (p = 0.035). However, in the LtS and LwS groups, no statistical difference was observed between expected (p = 0.114) and actual (p = 0.685) scores. The distribution of actual scores in the grading systems indicated higher percentages of excellent (grade A) and good (grade B) scores in the LwS (96.7%) and LtS (79.7%) groups, respectively, than in the L group (53.4%). Using computer-aided 3D simulation to teach the guidance of mandibular movement improved the learning outcomes and self-assessment of students, especially when 3D simulation was combined with conventional lecturing. Full article

(This article belongs to the Special Issue Applied Simulation and Experiment Research in Dentistry)

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8 pages, 1478 KiB

Open AccessArticle

Challenging the Resin-Zirconia Interface by Thermal Cycling or Mechanical Load Cycling or Their Combinations

by Sung-Min Kwon, Young Kyung Kim and Tae-Yub Kwon

Appl. Sci. 2020, 10(20), 7352; https://doi.org/10.3390/app10207352 - 20 Oct 2020

Cited by 2 | Viewed by 1977

Abstract

The purpose of this in vitro study was to evaluate the influence of mechanical load cycling (MLC), which simulated mastication, alone or combined with thermal cycling (TC), on the resin shear bond strength (SBS) to zirconia. Two resin cements (Panavia F2.0 and RelyX [...] Read more.

The purpose of this in vitro study was to evaluate the influence of mechanical load cycling (MLC), which simulated mastication, alone or combined with thermal cycling (TC), on the resin shear bond strength (SBS) to zirconia. Two resin cements (Panavia F2.0 and RelyX U200) were bonded (bonding area: 2.38 mm) to air-abraded zirconia (Everest ZS-Ronde). The specimens were subjected to SBS test before and after TC (5000 cycles), MLC (5000 cycles in 37 °C water), TC/MLC, or MLC/TC aging (n = 15). Before SBS test, the mechanical and physical properties of the two resin cements were studied (n = 5). For both resins, unlike TC (p > 0.05), the three MLC-containing aging conditions significantly decreased the SBS values when compared to the non-aged condition (p < 0.05). In the case of MLC-only aging, RelyX U200, with significantly higher hydrophobicity (p = 0.004), showed a significantly higher SBS value than Panavia F2.0 (p = 0.035). The MLC aging-containing groups showed increased occurrence of mixed failure. The application of MLC combined with TC may more closely simulate intraoral conditions. Full article

(This article belongs to the Special Issue Applied Simulation and Experiment Research in Dentistry)

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12 pages, 1902 KiB

Open AccessArticle

Comparative Analysis of the Smear Layer Removal Capability between EndoVac and Endoactivator Endodontic Irrigation Systems at the Root Canal System and Isthmus: A Micro-Computed Tomography Analysis

by Vicente Faus-Llácer, Mauricio Luna-Roa, Ignacio Faus-Matoses, Celia Ruiz-Sánchez, Álvaro Zubizarreta-Macho, Salvatore Sauro and Vicente Faus-Matoses

Appl. Sci. 2020, 10(20), 7033; https://doi.org/10.3390/app10207033 - 10 Oct 2020

Cited by 3 | Viewed by 2561

Abstract

The aim of this comparative study is to analyze the efficacy of EndoVac and Endoactivator endodontic irrigation systems for removing the endodontic smear layer present in the coronal, middle, and apical root third of the root canal system (RCS) and the isthmus from [...] Read more.

The aim of this comparative study is to analyze the efficacy of EndoVac and Endoactivator endodontic irrigation systems for removing the endodontic smear layer present in the coronal, middle, and apical root third of the root canal system (RCS) and the isthmus from mesial roots from the first lower molar teeth using micro-computed tomography (micro-CT) analysis. The study was performed on 40 mesial roots that were randomly assigned to the following groups: Group A, EndoVac endodontic irrigation system (EV) (n = 10); Group B, Endoactivator endodontic irrigation system (EA) (n = 10); Group C, Root canal systems performed with F2 ProTaper Gold endodontic rotary system but not irrigated (Positive control) (n = 10); Group D, Root canal systems not performed or irrigated (Negative control) (n = 10). The samples were exposed to micro-CT analysis and the mesial roots were segmented using an advanced image segmentation technique based on partial differential equations (ROI: 10 × 10 × 10 mm) and the root canal systems and isthmus were reconstructed at a resolution of 25 microns per voxel. The EA study group showed statistically significant different residual endodontic smear layer volume (0.48 ± 0.24 mm³) compared to the EV study group (0.18 ± 0.15 mm³) (p = 0.016). The EV endodontic irrigation system performed a higher smear layer removal at coronal and middle root thirds, compared to the EA endodontic irrigation system; however, the EA endodontic irrigation system performed a higher smear layer removal at the apical root third, compared to the EV endodontic irrigation system. Full article

(This article belongs to the Special Issue Applied Simulation and Experiment Research in Dentistry)

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13 pages, 1125 KiB

Open AccessArticle

Antibacterial Effects of MicroRepair^®BIOMA-Based Toothpaste and Chewing Gum on Orthodontic Elastics Contaminated In Vitro with Saliva from Healthy Donors: A Pilot Study

by Aida Meto, Bruna Colombari, Alessandra Odorici, Lavinia Beatrice Giva, Eva Pericolini, Annunziata La Regina and Elisabetta Blasi

Appl. Sci. 2020, 10(19), 6721; https://doi.org/10.3390/app10196721 - 25 Sep 2020

Cited by 10 | Viewed by 3584

Abstract

Several new products with innovative formulations are being proposed to facilitate oral care. Here, we evaluated the effects of a commercially available product, a toothpaste and chewing gum named Biorepair Peribioma, on oral microorganisms of healthy subjects. Saliva from six volunteers was collected [...] Read more.

Several new products with innovative formulations are being proposed to facilitate oral care. Here, we evaluated the effects of a commercially available product, a toothpaste and chewing gum named Biorepair Peribioma, on oral microorganisms of healthy subjects. Saliva from six volunteers was collected during 20 min of mastication of a traditional gum (gum A) and the Biorepair Peribioma gum (gum P). Orthodontic elastics (OE) were in vitro contaminated with salivary samples, both A and P, and subsequently exposed or not to a Biorepair Peribioma toothpaste-conditioned supernatant (Tp-SUP). The salivary samples were tested for initial microbial load; hence, the contaminated OE were assessed for microbial growth, adhesion, biofilm formation and persistence; moreover, species identification was assessed. We found that the salivary samples A and P had similar microbial load; upon contamination, microbial adhesion onto the OE was detected to a lower extent when using saliva P with respect to saliva A. Microbial growth and biofilm formation, assessed at 24 h, remained at lower levels in OE exposed to saliva P, compared to saliva A. This difference between salivary samples A and P was confirmed when measuring biofilm persistence (48 h), while it was lost in terms of microbial re-growth (48 h). The Tp-SUP treatment drastically affected microbial load at 24 h and strongly impaired biofilm formation/persistence, in OE exposed to both salivary samples A and P. Finally, such treatment resulted in consistent overgrowth of Lactobacilli, bacterial species originally present both in the Biorepair Peribioma toothpaste and gum. In conclusion, by an in vitro pilot study, we show that the Biorepair Peribioma toothpaste and gum deeply affect oral microorganisms’ behavior, drastically impairing their ability to contaminate and produce plaque onto orthodontic devices. Full article

(This article belongs to the Special Issue Applied Simulation and Experiment Research in Dentistry)

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10 pages, 1208 KiB

Open AccessArticle

Rubber Dam Isolation and High-Volume Suction Reduce Ultrafine Dental Aerosol Particles: An Experiment in a Simulated Patient

by Julián Balanta-Melo, Albio Gutiérrez, Gustavo Sinisterra, María del Mar Díaz-Posso, David Gallego, Judy Villavicencio and Adolfo Contreras

Appl. Sci. 2020, 10(18), 6345; https://doi.org/10.3390/app10186345 - 11 Sep 2020

Cited by 17 | Viewed by 6011

Abstract

The ongoing Coronavirus Disease 2019 (COVID-19) pandemic has triggered the paralysis of dental services ascribed to the potential spread of severe acute respiratory syndrome (SARS)-CoV-2. Aerosol-generating procedures (AGPs) are common in dentistry, which in turn increase the risk of infection of the dental [...] Read more.

The ongoing Coronavirus Disease 2019 (COVID-19) pandemic has triggered the paralysis of dental services ascribed to the potential spread of severe acute respiratory syndrome (SARS)-CoV-2. Aerosol-generating procedures (AGPs) are common in dentistry, which in turn increase the risk of infection of the dental personnel due to the salivary presence of SARS-CoV-2 in COVID-19 patients. The use of rubber dam isolation (RDI) and high-volume evacuators (HVE) during AGPs is recommended to control dental aerosols, but the evidence about their effectiveness is scarce. This first study aimed to compare, in a simulated patient, the effectiveness of the following strategies: standard suction (SS), RDI and RDI + HVE. Using the laser diffraction technique, the effect of each condition on the volume distribution, average size and concentration of coarse (PM₁₀), fine (PM_2.5) and ultrafine (PM_0.1) particles were evaluated. During the teeth drilling, the highest volume fraction of dental aerosol particles with SS was below 1 μm of aerodynamic diameter. Additionally, the RDI + HVE significantly reduced both the ultrafine dental aerosol particles and the concentration of total particulate matter. AGPs represent a potential risk for airborne infections in dentistry. Taken together, these preliminary results suggest that isolation and high-volume suction are effective to reduce ultrafine dental aerosol particles. Full article

(This article belongs to the Special Issue Applied Simulation and Experiment Research in Dentistry)

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9 pages, 2949 KiB

Open AccessArticle

Computer-Based 3D Simulation Method in Dental Occlusion Education: Student Response and Learning Effect

by Hai Yen Mai, Hang-Nga Mai and Du-Hyeong Lee

Appl. Sci. 2020, 10(17), 6073; https://doi.org/10.3390/app10176073 - 2 Sep 2020

Cited by 4 | Viewed by 3810

Abstract

Occlusion is a fundamental subject in dental education, and occlusal adjustment is clinically essential in daily dental practices. This study aimed to assess the effects of computer-based 3D simulations on learner responses and learning effect on the principles of occlusal adjustment in undergraduate [...] Read more.

Occlusion is a fundamental subject in dental education, and occlusal adjustment is clinically essential in daily dental practices. This study aimed to assess the effects of computer-based 3D simulations on learner responses and learning effect on the principles of occlusal adjustment in undergraduate dental students in comparison with the traditional approach. Two teaching methods, i.e., paper-based 2D presentation and computer-based 3D simulation, were used for teaching the occlusal adjustment concepts. Sixty dental students were divided into two groups using a pair-matching randomization method. In the 2D presentation group, a textbook with 2D illustrations was used. 3D graphic dental models and computer design software were applied in the 3D simulation group. After the course, an attitudinal survey and examination were conducted to evaluate the participants’ feedback and the learning effects resulting from the teaching methods. The independent t test was used to compare the test scores between groups (with α = 0.5). Pearson’s correlation coefficient was calculated to investigate the agreement between the survey data and test scores. Most of the students’ feedback indicated that the 3D simulation method would be effective in acquiring knowledge on occlusion and jaw movement. The examination scores were significantly higher in the 3D simulation group compared with those in the 2D presentation group in the questions for centric relation (P = 0.034). Conversely, the scores were insignificant in the questions for eccentric relation (P = 0.403). There was no correlation observed between the survey data and the actual examination score. Computer-based 3D simulation could increase the participants’ expectations and learning effects in dental occlusion education. Further studies in diversified learning environments are required on the efficacy of digital educational modality. Full article

(This article belongs to the Special Issue Applied Simulation and Experiment Research in Dentistry)

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11 pages, 2384 KiB

Open AccessArticle

Prediction of Health Care Costs by Dental Health Care Costs and Periodontal Status

by Yoshiaki Nomura, Tetsuro Sato, Yoshinori Kamoshida, Syunsuke Suzuki, Ayako Okada, Ryoko Otsuka, Erika Kakuta and Nobuhiro Hanada

Appl. Sci. 2020, 10(9), 3140; https://doi.org/10.3390/app10093140 - 30 Apr 2020

Cited by 3 | Viewed by 2152

Abstract

Reducing heath care costs is an important issue in Japan. The aim of this study was to analyze the contribution of oral health to health care costs and to predict health care costs by statistical modeling. Data from 46 individuals (29 men and [...] Read more.

Reducing heath care costs is an important issue in Japan. The aim of this study was to analyze the contribution of oral health to health care costs and to predict health care costs by statistical modeling. Data from 46 individuals (29 men and 17 women; mean age of 44.6 ± 1.7 years) on health care costs, dental health care costs, and the results of the salivary levels of lactate dehydrogenase (LD) over two years were provided by the association. Multilayer perceptron neural networks were applied to predict the health care costs from data from the previous year and included health care costs, dental health care costs, and salivary levels of LD. Nonlinear relationships were observed between medical health care costs, dental health care costs, and periodontal conditions. The health care costs from the previous year were the most important predictor of health care costs. The simulation results showed that health care costs decreased with the increase in dental health care costs from the previous year. Health care costs increased with increasing salivary levels of LD from the previous year. Improvements in periodontal conditions and dental health care may play some roles in reducing health care costs. Full article

(This article belongs to the Special Issue Applied Simulation and Experiment Research in Dentistry)

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7 pages, 613 KiB

Open AccessArticle

Biomechanical Evaluation of Sagittal Split Ramus Osteotomy Fixation Techniques in Mandibular Setback

by Michael Y. C. Chen, Yi-Fan Wu, Heng-Li Huang and Jui-Ting Hsu

Appl. Sci. 2020, 10(9), 3031; https://doi.org/10.3390/app10093031 - 26 Apr 2020

Cited by 3 | Viewed by 5051

Abstract

The objective of this study was to evaluate and compare the biomechanical behavior of internal fixation techniques in bilateral sagittal split ramus osteotomies (BSSROs) for mandibular setback. Artificial polyurethane mandibles were used in this study. The distal segment of the mandible was repositioned [...] Read more.

The objective of this study was to evaluate and compare the biomechanical behavior of internal fixation techniques in bilateral sagittal split ramus osteotomies (BSSROs) for mandibular setback. Artificial polyurethane mandibles were used in this study. The distal segment of the mandible was repositioned in an 8-mm setback position. All mandibles were divided into three groups: Group 1 had a straight plate with a four-hole monocortical fixation, Group 2 had a curved plate with a four-hole monocortical fixation, and Group 3 had a three–inverted L-type bicortical screw fixation. Vertical loads were applied on the incisal edge by a material testing system. The resistance force at 1, 3, 5, and 10 mm of displacement was analyzed. From the experimental results, Group 1 showed significantly lower results than Groups 2 and 3. No significant difference was observed between Groups 2 and 3 at 1, 3, and 5 mm of displacement. However, at 10 mm of displacement, the resistance force of Group 3 was greater than that of Group 2. For BSSROs, this study concluded that curved plate fixation exhibited the same rigidity as the inverted-L bicortical screw fixation did at ≤5 mm displacement. Full article

(This article belongs to the Special Issue Applied Simulation and Experiment Research in Dentistry)

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10 pages, 1691 KiB

Open AccessArticle

Mandible Integrity and Material Properties of the Periodontal Ligament during Orthodontic Tooth Movement: A Finite-Element Study

by Heng-Li Huang, Ming-Tzu Tsai, Shih-Guang Yang, Kuo-Chih Su, Yen-Wen Shen and Jui-Ting Hsu

Appl. Sci. 2020, 10(8), 2980; https://doi.org/10.3390/app10082980 - 24 Apr 2020

Cited by 12 | Viewed by 3542

Abstract

We used the finite-element method (FEM) to investigate the effects of jawbone model integrity and the material properties of the periodontal ligament (PDL) on orthodontic tooth movement. Medical imaging software and computer-aided design software were used to create finite-element models of a partial [...] Read more.

We used the finite-element method (FEM) to investigate the effects of jawbone model integrity and the material properties of the periodontal ligament (PDL) on orthodontic tooth movement. Medical imaging software and computer-aided design software were used to create finite-element models of a partial and complete mandibles based on dental cone beam computed tomography images of the human skull. Additionally, we exerted an orthodontic force on the canine crown in the direction of an orthodontic miniscrew under a lower molar root to compare the von Mises strain on the canine PDL in three models: a partial mandible model under orthodontic force (Model 1), a complete mandible model under orthodontic force (Model 2), and a complete mandible model under orthodontic force with clench occlusion in the intercuspal position (ICP; Model 3). Additionally, in the complete mandible model under orthodontic force with ICP occlusion, we analyzed the effects of a PDL with a low (Model 4), moderate (Model 5), and high (Model 6) linear elastic modulus and a PDL a bilinear elastic modulus (Model 7). The simulation results for mandible integrity indicated that the maximum von Mises strains on the canine PDL for Models 1, 2, and 3 were 0.461, 0.394, and 1.811, respectively. Moreover, for the models with different PDL material properties, the maximum von Mises strains on the canine PDLs for Models 4, 5, 6, and 7 were 6.047, 2.594, 0.887, and 1.811, respectively. When the FEM was used to evaluate tooth movement caused by orthodontic force, the transformation of a complete mandible model into a partial mandible model or alteration of the elastic modulus of the PDL influenced the biomechanical responses of the PDL. Additionally, the incorporation of daily ICP occlusion resulted in a larger effect. Full article

(This article belongs to the Special Issue Applied Simulation and Experiment Research in Dentistry)

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11 pages, 1150 KiB

Open AccessArticle

Concentration in Saliva and Antibacterial Effect of Xylitol Chewing Gum: In Vivo and In Vitro Study

by Fabio Cocco, Maria Grazia Cagetti, Osama Majdub and Guglielmo Campus

Appl. Sci. 2020, 10(8), 2900; https://doi.org/10.3390/app10082900 - 22 Apr 2020

Cited by 5 | Viewed by 5579

Abstract

Purpose. The saliva concentration of xylitol released from two chewing gums was recorded, the first containing xylitol as the only sweetener (100% xylitol) and the second containing only 22% of the polyol. In addition, the in vitro antibacterial effect of the two [...] Read more.

Purpose. The saliva concentration of xylitol released from two chewing gums was recorded, the first containing xylitol as the only sweetener (100% xylitol) and the second containing only 22% of the polyol. In addition, the in vitro antibacterial effect of the two chewing gums was evaluated. Materials and Methods. The salivary concentration of Xylitol in 32 subjects was determined before and at 0.30, 1.00, 2.00, 5.00, and 10.00 min while using the chewing gums, and at 15.00, 20.00, and 25.00 min after the gums were discarded. In vitro antibacterial activity was determined on a pooled subgingival plaque sample obtained from four patients with periodontal disease. Cariogenic and periodontal bacteria were evaluated before and 15 min, 60 min, and 24 h after gum contact. Results. Using the 100% xylitol chewing gum, saliva levels increased bimodally, one peak after 30 s (1.49 ± 1.41 logμg/L) and a second one at a 10-min evaluation (1.41 ± 1.11 logμg/L); the 22% chewing gum peaked only two minute after contact (1.21 ± 1.24 logμg/L). Overall, a statistically significantly higher salivary concentration of xylitol was detected using the 100% xylitol gum. All bacteria decreased after the addition of the two chewing gums; the 100% gum achieved a greater decrease than the 22% gum. Conclusion. The use of both chewing gums increased the concentrations of xylitol in saliva, with a statistically significantly higher concentration using the 100% xylitol gum. Cariogenic and periodontal bacteria were reduced by both chewing gums; 100% xylitol gum produced the highest and longest lasting effect. This study opens up to the use of xylitol against periodontal disease. Full article

(This article belongs to the Special Issue Applied Simulation and Experiment Research in Dentistry)

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12 pages, 1274 KiB

Open AccessArticle

Influence of Occlusal Thickness and Radicular Extension on the Fracture Resistance of Premolar Endocrowns from Different All-Ceramic Materials

by Satheesh B. Haralur, Alaa Ali Alamri, Shatha Abdulrahman Alshehri, Danyah Saeed Alzahrani and Mohammed Alfarsi

Appl. Sci. 2020, 10(8), 2696; https://doi.org/10.3390/app10082696 - 14 Apr 2020

Cited by 10 | Viewed by 3948

Abstract

Endocrowns are primarily recommended in a molar region with a standardized preparation design. The aim of the study was to evaluate the effect of different occlusal preparation depths, pulp chamber-radicular extension, and all-ceramic materials on the fracture resistance of premolar endocrowns. Ninety human [...] Read more.

Endocrowns are primarily recommended in a molar region with a standardized preparation design. The aim of the study was to evaluate the effect of different occlusal preparation depths, pulp chamber-radicular extension, and all-ceramic materials on the fracture resistance of premolar endocrowns. Ninety human premolar teeth were root canal treated, randomly divided into three main groups according to all-ceramic material used for fabrication as Lithium Disilicate (LD) ceramic, Polymer infiltrated ceramic (PIC) and High translucency zirconia (HTZ). They were further subdivided into three subgroups (n = 10) according to preparation design of 2 mm occlusal reduction, 4.5 mm occlusal reduction and 4.5 mm occlusal reduction with 2 mm radicular extension. The endocrowns from respective restorative materials were fabricated, surface conditioned, and cemented with self-adhesive resin cement. All samples were thermocycled for 5000 cycles and subjected to compressive static load at 45° angluation with the cross-head speed of 0.5 mm/minute until the fracture. The mean fracture resistance of LD ceramic at 2 mm, 4.5 mm thickness and radicular extension was 62.55 MPa, 45.80 MPa, 74.27 MPa respectively. The corresponding values for the PIC and HTZ ceramics were 26.30 MPa, 21.65 MPa, 25.66 Mpa and 23.47 MPa, 27.30 MPa, 37.29 MPa respectively. The LD ceramic and greater extension inside the pulp chamber had higher fracture resistance. Full article

(This article belongs to the Special Issue Applied Simulation and Experiment Research in Dentistry)

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9 pages, 2019 KiB

Open AccessCase Report

Virtual Reality Simulation and Augmented Reality-Guided Surgery for Total Maxillectomy: A Case Report

by Hee-Jin Kim, Ye-Joon Jo, Jun-Seok Choi, Hyo-Joon Kim, In-Seok Park, Jae-Seek You, Ji-Su Oh and Seong-Yong Moon

Appl. Sci. 2020, 10(18), 6288; https://doi.org/10.3390/app10186288 - 10 Sep 2020

Cited by 15 | Viewed by 3340

Abstract

With the improvement in computer graphics and sensors, technologies like virtual reality (VR) and augmented reality (AR) have created new possibilities for developing diagnostic and surgical techniques in the field of surgery. VR and AR are the latest technological modalities that have been [...] Read more.

With the improvement in computer graphics and sensors, technologies like virtual reality (VR) and augmented reality (AR) have created new possibilities for developing diagnostic and surgical techniques in the field of surgery. VR and AR are the latest technological modalities that have been integrated into clinical practice and medical education, and are rapidly emerging as powerful tools in the field of maxillofacial surgery. In this report, we describe a case of total maxillectomy and orbital floor reconstruction in a patient with malignant fibrous histiocytoma of the maxilla, with preoperative planning via VR simulation and AR-guided surgery. Future developments in VR and AR technologies will increase their utility and effectiveness in the field of surgery. Full article

(This article belongs to the Special Issue Applied Simulation and Experiment Research in Dentistry)

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