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Seki K, Nagasaki M, Yoshino T, Yano M, Kawamoto A, Shimizu O. Radiographical Diagnostic Evaluation of Mandibular Cortical Index Classification and Mandibular Cortical Width in Female Patients Prescribed Antiosteoporosis Medication: A Retrospective Cohort Study. Diagnostics (Basel) 2024; 14:1009. [PMID: 38786307 PMCID: PMC11119882 DOI: 10.3390/diagnostics14101009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2024] [Revised: 05/09/2024] [Accepted: 05/13/2024] [Indexed: 05/25/2024] Open
Abstract
Osteoporosis is often detected late and becomes severe because of a lack of subjective symptoms. Digital panoramic radiography (DPR) has been reported to be useful for osteoporosis screening based on the morphological classification of the mandibular inferior cortex. The purpose of this study was to evaluate the sensitivity and specificity of the mandibular cortical index (MCI) in the diagnosis of osteoporosis in a group of patients who were and were not using antiosteoporosis medication (AOM). Three hundred and fifty female patients aged 40 years or older who had DPR imaging performed during a 6-year period from December 2015 to February 2022 met the selection criteria. Two examiners recorded mandibular cortical width and MCI from the images. These results were statistically examined together with the patients' demographic data. Forty-nine patients were using AOM (13 nonbisphosphonate/denosumab and 36 bisphosphonate/denosumab). MCI type 3 was the most common in the AOM group. In the MCI classification, DPR imaging among the AOM group was more sensitive (0.95) than that of the control group. This method of estimating osteoporosis based on MCI classification using DPR images has high sensitivity, especially in patients using AOM, suggesting that this method is useful as a screening test.
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Affiliation(s)
- Keisuke Seki
- Department of Comprehensive Dentistry and Clinical Education, Nihon University School of Dentistry, 1-8-13, Kanda-Surugadai, Chiyoda-ku, Tokyo 101-8310, Japan
- Division of Dental Education, Dental Research Center, Nihon University School of Dentistry, 1-8-13, Kanda-Surugadai, Chiyoda-ku, Tokyo 101-8310, Japan
| | - Maki Nagasaki
- Department of Oral and Maxillofacial Surgery I, Nihon University School of Dentistry, 1-8-13, Kanda-Surugadai, Chiyoda-ku, Tokyo 101-8310, Japan; (M.N.); (O.S.)
| | - Tona Yoshino
- Department of Oral and Maxillofacial Surgery, Yokohama City University Graduate School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama 236-0004, Japan;
| | - Mayuko Yano
- Nihon University School of Dentistry Dental Hospital, 1-8-13, Kanda-Surugadai, Chiyoda-ku, Tokyo 101-8310, Japan;
| | - Aki Kawamoto
- Dental Hygienist Section, Nihon University School of Dentistry Dental Hospital, 1-8-13, Kanda-Surugadai, Chiyoda-ku, Tokyo 101-8310, Japan;
| | - Osamu Shimizu
- Department of Oral and Maxillofacial Surgery I, Nihon University School of Dentistry, 1-8-13, Kanda-Surugadai, Chiyoda-ku, Tokyo 101-8310, Japan; (M.N.); (O.S.)
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Wang X, Liu H, Zhang X, Qu Z, Zhao J. Effect of transcutaneous electrical nerve stimulation (TENS) on the electromyographic activity of human masticatory muscles in young people with normal occlusion. J Prosthet Dent 2024:S0022-3913(24)00214-2. [PMID: 38714456 DOI: 10.1016/j.prosdent.2024.03.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2023] [Revised: 03/12/2024] [Accepted: 03/14/2024] [Indexed: 05/09/2024]
Abstract
STATEMENT OF PROBLEM Transcutaneous electrical nerve stimulation (TENS) has been used in several clinical areas. However, the effect of TENS on the masticatory muscles of young individuals with normal occlusion remains unclear. PURPOSE The purpose of the study was to assess the effect of TENS on the surface electromyographic (sEMG) activity of masticatory muscles in a young population with normal occlusion. MATERIAL AND METHODS Twenty residents (5 men and 15 women, mean 24.27 ±2.59 years) of Dalian Stomatological Hospital were enrolled as the study participants. A trained operator collected the required information from the participants. The experiment was divided into 3 stages: pre-TENS acquisition, TENS application, and post-TENS acquisition. The pre-TENS stage was performed using surface electromyography (sEMG) (Myotronics Inc) to acquire the potential values of masticatory muscles in the following 3 states 5 times each: resting, intercuspal occlusion (ICO), and maximum voluntary clench (clenching). The potential values of the anterior of temporalis (TA), the masseter (MM), the sternocleidomastoid (SCM), and the anterior digastric (DA) muscles were collected in the resting state, and TA and MM were collected in the ICO and clenching states. During the TENS application phase, a TENS Unit device (J5 Myomonitor) (J5) was used on each participant for 45 minutes. The post-TENS acquisition phase involved the same procedure as the pre-TENS phase. The experimental data were recorded, and the normality of each group was analyzed using the Shapiro-Wilk test in a statistical software program (IBM SPSS Statistics, v26.0). The paired-sample t test was used to compare the differences in the mean values of sEMG and the asymmetry index (As); the independent-sample t test was used to compare the activity index (Ac) and torque index (To) (α=.05). RESULTS Significant differences were observed in the mean potential values of TA, MM, LSCM, and RDA before and after TENS in the resting state and RTA, LMM, and RMM before and after TENS in the clenching state (P<.05). Moreover, although AsDA values showed a significant difference (P=.027) before and after TENS in the resting state, the differences in As values for the other muscles in the resting state were statistically similar. Furthermore, in each state, the mean values of Ac and To after TENS showed no significant differences before and after TENS (P>.05). CONCLUSIONS The resting EMG values of the TA and MM differed significantly before and after TENS. After TENS, the resting EMG activity decreased, whereas the functional EMG activity tended to increase.
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Affiliation(s)
- Xingyu Wang
- Graduate student, Dalian Stomatological Hospital, Dalian, PR China
| | - Hao Liu
- Graduate student, Graduate Prosthodontics, Graduate School, Dalian Medical University, Dalian, PR China
| | - Xiangting Zhang
- Graduate student, Graduate Prosthodontics, Graduate School, Dalian Medical University, Dalian, PR China
| | - Zhe Qu
- Professor, Department of Implant Dentistry, Dalian Stomatological Hospital, Dalian, PR China
| | - Jiaming Zhao
- Professor, Department of Implant Dentistry, Dalian Stomatological Hospital, Dalian, PR China.
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El Charkawi H, Nassar HI, Abdelaziz MS. Retrospective digital study of mandibular flexure in patients with long-span fixed restorations supported by natural teeth. BMC Res Notes 2023; 16:203. [PMID: 37697386 PMCID: PMC10494340 DOI: 10.1186/s13104-023-06486-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Accepted: 08/30/2023] [Indexed: 09/13/2023] Open
Abstract
PURPOSE This retrospective study aims to evaluate the mandibular flexure on a long-span rigid fixed prosthesis supported by natural teeth. MATERIALS AND METHODS Nine patients (five males and four females) were included in this study who had long-span rigid mandibular fixed prostheses for long-term (10-15 years) that have led to radiographic changes around the supporting teeth. The mandibular flexure was measured digitally after adhering reference markers to the prostheses. Intraoral scans were obtained at the minimum and maximum mouth openings before and after splitting the preexisting prostheses. The distances between the markers were measured, and mandibular flexure was calculated. RESULTS This study showed a significant deviation (narrowing) of the mandible before and after splitting the rigid fixed prostheses (P value < 0.05). CONCLUSION Digital analysis of the data collected from the patients in this retrospective study indicated that deviations occur during mandibular flexure. CLINICAL RELEVANCE Splitting the full arch prosthesis could prevent the negative consequences of mandibular flexure on restorations. Trial registration The study was registered on clinicaltrials.gov with registration number NCT05617274 (15/11/2022).
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Affiliation(s)
- Hussein El Charkawi
- Department of Prosthodontics, Faculty of Oral and Dental Medicine, Future University in Egypt, Fifth Settlement, End of 90 Street, New Cairo, Egypt
| | - Hossam I Nassar
- Department of Prosthodontics, Faculty of Oral and Dental Medicine, Future University in Egypt, Fifth Settlement, End of 90 Street, New Cairo, Egypt
| | - Medhat Sameh Abdelaziz
- Department of Prosthodontics, Faculty of Oral and Dental Medicine, Future University in Egypt, Fifth Settlement, End of 90 Street, New Cairo, Egypt.
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Caggiano M, D’Ambrosio F, Acerra A, Giudice D, Giordano F. Biomechanical Implications of Mandibular Flexion on Implant-Supported Full-Arch Rehabilitations: A Systematic Literature Review. J Clin Med 2023; 12:5302. [PMID: 37629344 PMCID: PMC10455661 DOI: 10.3390/jcm12165302] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Revised: 08/03/2023] [Accepted: 08/09/2023] [Indexed: 08/27/2023] Open
Abstract
BACKGROUND Mandibular flexion (MF) is a complex biomechanical phenomenon, which involves a deformation of the mandible, due mainly to the contraction of the masticatory muscles, and it can have numerous clinical effects. The deformation of the lower jaw caused by mandibular flexion is generally very small, and it is often overlooked and considered irrelevant from a clinical point of view by many authors; however, it should be important to remember that median mandibular flexure (MMF) has a multifactorial aetiology. The main aim of the current systematic review is to highlight the different factors that can increase MF in order to help clinicians identify patients to whom they should pay more attention. As a secondary outcome, we wanted to analyse the preventive measures and suitable techniques to be adopted to minimise the negative effects of this phenomenon on oral fixed rehabilitations. METHODS The review, which was carried out in accordance with the "Preferred Reporting Items for Systematic reviews and Meta-Analyses" (PRISMA) flowchart, was recorded in the "International Prospective Register of Systematic Reviews" (PROSPERO). As research questions, "Patient/Population, Intervention, Comparison and Outcomes" (PICO) questions were employed. Using the ROBINS-I technique, the risk of bias in non-randomised clinical studies was evaluated. RESULTS The initial electronic search identified over 1300 potential articles, of which 54 studies were included in this systematic review. Information regarding the relationship between MF and individual factors, mandibular movements, impression taking, and fixed rehabilitations were obtained. CONCLUSIONS The studies included in this systematic review showed that MF is greater during protrusive movements, in the posterior areas of the lower jaw, and in patients with brachial facial type, greater jaw length; small gonial angle; and less density, length, and bone surface of the symphysis. The biomechanical effects of mandibular flexion on fixed restorations are debated. Prospective clinical and radiological observational studies should be conducted to evaluate the potential short-, medium-, and long-term consequences of MF.
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Affiliation(s)
- Mario Caggiano
- Department of Medicine, Surgery and Dentistry, University of Salerno, Via Allende, Baronissi, 84081 Salerno, Italy; (F.D.); (D.G.); (F.G.)
| | | | - Alfonso Acerra
- Department of Medicine, Surgery and Dentistry, University of Salerno, Via Allende, Baronissi, 84081 Salerno, Italy; (F.D.); (D.G.); (F.G.)
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Londono J, Schoenbaum TR, Varilla Ortiz AV, Franco-Romero G, Villalobos V, Carosi P, Mijiritsky E, Pozzi A. Mandibular Flexure and Its Significance: An In Vivo Cone Beam-Computed Tomography Proof-of-Concept Study. J Clin Med 2023; 12:4149. [PMID: 37373841 PMCID: PMC10299314 DOI: 10.3390/jcm12124149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Revised: 06/11/2023] [Accepted: 06/16/2023] [Indexed: 06/29/2023] Open
Abstract
The aim of this study was to assess intra-arch mandibular dimensional changes that may occur during mouth opening using cone beam-computed tomography (CBCT). Fifteen patients in need of any type of treatment whose execution considered a pre- and post-CBCT assessment consented and were enrolled. CBCTs were taken with the following settings: 90 kV, 8 mA, field of view (FOV) 140 by 100 mm (height and diameter), Voxel size 0.25 mm (high resolution). The pre-CBCT was executed in the maximum mandibular opening (MO), while the post-CBCT was in the maximum intercuspation (MI). A thermoplastic stent with radiopaque fiducial markers (steel ball bearings) was fabricated for each patient. Measurements were made using radiographic markers between contralateral canines and contralateral first molars and between ipsilateral canines and first molars on both sides. Paired t-tests were performed to evaluate the difference between open and closed positions on these four measurements. In the MO position were registered a significative tightening of the mandible at the canine (-0.49 mm, SD 0.54 mm; p < 0.001) and molar points (-0.81 mm, SD 0.63 mm; p < 0.001) and a significative shortening of the mandible on the right (-0.84 mm, SD 0.80 mm; p < 0.001) and left sides (-0.87 mm, SD 0.49 mm; p < 0.001). Within the study limitations, mandibular flexure determined a significant shortening and tightening between maximum intercuspation to maximum opening positions. Mandibular dimensional changes should be considered in light of other patient factors in the treatment planning of implant positioning and long-span complete arch implant-supported fixed prostheses in order to avoid technical complications.
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Affiliation(s)
- Jimmy Londono
- Ronald Goldstein Center for Esthetic and Implant Dentistry, Department of Restorative Sciences, Dental College of Georgia, Augusta, GA 30912, USA;
| | - Todd R. Schoenbaum
- Department of Restorative Sciences, Dental College of Georgia, Augusta, GA 30912, USA; (T.R.S.); (V.V.)
| | | | - Guillermo Franco-Romero
- Stomatology and Oral Rehabilitation Residency Program, Benemerita Universidad Autonoma de Puebla, Puebla 72000, Mexico;
| | - Vanessa Villalobos
- Department of Restorative Sciences, Dental College of Georgia, Augusta, GA 30912, USA; (T.R.S.); (V.V.)
| | - Paolo Carosi
- Department of Clinical Sciences and Translational Medicine, School of Dentistry, University of Tor Vergata, 00133 Rome, Italy;
| | - Eitan Mijiritsky
- The Maurice and Gabriela Goldschleger School of Dental Medicine, Tel Aviv University, Tel Aviv 6997801, Israel;
- Head and Neck Maxillofacial Surgery, Tel Aviv Sourasky Medical Center, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 6139001, Israel
| | - Alessandro Pozzi
- Ronald Goldstein Center for Esthetic and Implant Dentistry, Department of Restorative Sciences, Dental College of Georgia, Augusta, GA 30912, USA;
- Department of Clinical Sciences and Translational Medicine, School of Dentistry, University of Tor Vergata, 00133 Rome, Italy;
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Zhong S, Shi Q, Van Dessel J, Gu Y, Sun Y, Yang S. Biomechanical validation of structural optimized patient-specific mandibular reconstruction plate orienting additive manufacturing. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2022; 224:107023. [PMID: 35872386 DOI: 10.1016/j.cmpb.2022.107023] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Revised: 07/07/2022] [Accepted: 07/12/2022] [Indexed: 06/15/2023]
Abstract
BACKGROUND AND OBJECTIVE Owing to the unexpected in vivo fracture failure of the original design, structural optimized patient-specific mandibular reconstruction plates (PSMRPs) were created to boost the biomechanical performance of bridging segmental bony defect in the mandibular reconstruction after tumor resection. This work aimed to validate the biomechanical benefit of the structural optimized PSMRPs relative to the original design and compare the biomechanical performance between PSMRP1 with generic contour customization and PSMRP2 with a tangent arc upper margin in mandibular angle region. METHODS Finite Element Analysis (FEA) was used to evaluate the biomechanical behavior of mandibular reconstruction assemblies (MRAs) concerning these two structural optimized PSMRPs by simulating momentary left group clenching and incisal clenching tasks. Bonded contact was set between mandibular bone and fixation screws and between PSMRP and fixation screws in the MRA, while the frictionless connection was allocated between mandibular bone and PSMRP. The loads were applied on four principal muscles, including masseter, temporalis, lateral and medial pterygoid, whose magnitudes along the three orthogonal directions. The mandibular condyles were retrained in all three directions, and either the left molars or incisors area were restrained from moving vertically. RESULTS The peak von Mises stresses of structural optimized PSMRPs (264 MPa, 296 MPa) were way lower than that of the initial PSMRP design (393 MPa), with 33 and 25% reduction during left group clenching. The peak magnitude of von Mises stress, minimum principal stress, and maximum principal strain of PSMRP1 (264 MPa, 254 MPa; -297 MPa, -285 MPa; 0.0020, 0.0020) was lower than that of PSMRP2 (296 MPa, 286 MPa; -319 MPa, -306 MPa; 0.0022, 0.0020), while the peak maximum principal stress of PSMRP1 (275 MPa, 257 MPa) was higher than that of PSMRP2 (254 MPa, 235 MPa) during both left group clenching and incisal clenching tasks. CONCLUSIONS The structural optimized PSMRPs reveal their biomechanical advantage compared with the original design. The PSMRP1 presents better biomechanical performance to the patient-specific mandibular reconstruction than PSMRP2 as a result of its superior safety, preferable flexibility, and comparable stability. The PSMRP2 provides biomechanical benefit in reducing the maximum tension than PSMRP1, indicated by lower peak maximum principal stress, through tangent arc upper margin in mandibular angle region.
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Affiliation(s)
- Shengping Zhong
- Department of Imaging & Pathology, Faculty of Medicine, KU Leuven & Oral and Maxillofacial Surgery, University Hospitals Leuven, Kapucijnenvoer 33, Leuven 3000, Belgium
| | - Qimin Shi
- Department of Imaging & Pathology, Faculty of Medicine, KU Leuven & Oral and Maxillofacial Surgery, University Hospitals Leuven, Kapucijnenvoer 33, Leuven 3000, Belgium
| | - Jeroen Van Dessel
- Department of Imaging & Pathology, Faculty of Medicine, KU Leuven & Oral and Maxillofacial Surgery, University Hospitals Leuven, Kapucijnenvoer 33, Leuven 3000, Belgium
| | - Yifei Gu
- Department of Imaging & Pathology, Faculty of Medicine, KU Leuven & Oral and Maxillofacial Surgery, University Hospitals Leuven, Kapucijnenvoer 33, Leuven 3000, Belgium
| | - Yi Sun
- Department of Imaging & Pathology, Faculty of Medicine, KU Leuven & Oral and Maxillofacial Surgery, University Hospitals Leuven, Kapucijnenvoer 33, Leuven 3000, Belgium.
| | - Shoufeng Yang
- Faculty of Engineering and Physical Sciences, Highfield, University of Southampton, Southampton SO17 1BJ, United Kingdom.
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Gülsoy M, Tuna SH, Pekkan G. Evaluation of median mandibular flexure values in dentulous and edentulous subjects by using an intraoral digital scanner. J Adv Prosthodont 2022; 14:32-44. [PMID: 35284055 PMCID: PMC8891685 DOI: 10.4047/jap.2022.14.1.32] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Revised: 12/23/2021] [Accepted: 01/25/2022] [Indexed: 11/16/2022] Open
Abstract
PURPOSE Mandibular flexure is a crucial phenomenon that may affect the success of rigid bilateral mandibular prosthetic treatment. The aim of this study was to determine the amount of median mandibular flexure (MMF) that occurs during mouth opening from anterior to posterior mandible in seven different regions, in different age and gender groups of both dentulous and edentulous subjects, using an intraoral digital scanner. MATERIALS AND METHODS In this study, the mandibular arch of 56 dentulous and 35 edentulous individuals were scanned with an intraoral scanner at both the minimum mouth opening (MnMO) and the maximum mouth opening (MxMO). MMF values were calculated by subtracting the distance value at the MxMO from the distance between the reference points at the MnMO at seven different mandibular regions of dentulous and edentulous subjects. In addition, the left and right side MMF values were measured. All data were analyzed statistically (α = .05). RESULTS MMF value increased linearly from anterior to posterior mandible in both dentulous and edentulous individuals. The differences in MMF values were not statistically significant according to side (left/right), age, or gender (P > .05). No significant differences were found between the mean MMF values of the same region in both dentulous and edentulous individuals (P > .05). CONCLUSION MMF was seen in different regions of the mandibles of both edentulous and dentulous individuals measured at the MxMO. Mandibular flexure should be considered for the success and prognosis of the long-span and rigid prostheses.
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Affiliation(s)
- Merve Gülsoy
- Department of Prosthodontics, Faculty of Dentistry, Süleyman Demirel University, Isparta, Turkey
| | - Süleyman Hakan Tuna
- Department of Prosthodontics, Faculty of Dentistry, Süleyman Demirel University, Isparta, Turkey
| | - Gürel Pekkan
- Department of Prosthodontics, Faculty of Dentistry, Tekirdag Namik Kemal University, Tekirdag, Turkey
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Li L, Chen H, Li W, Wang Y, Sun Y. Design of wear facets of mandibular first molar crowns by using patient-specific motion with an intraoral scanner: A clinical study. J Prosthet Dent 2021; 129:710-717. [PMID: 34426014 DOI: 10.1016/j.prosdent.2021.06.048] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Revised: 06/29/2021] [Accepted: 06/29/2021] [Indexed: 11/24/2022]
Abstract
STATEMENT OF PROBLEM Although computer-aided design has become popular, restorations are typically designed from static occlusion and dynamically by using an average-value virtual articulator. Patient-specific motion recorded by using an intraoral scanner has rarely been used to design restorations, and its design ability has not been analyzed. PURPOSE The purpose of this clinical study was to record patient-specific motion by using an intraoral scanner and to analyze its ability to design the morphology of the wear facets on mandibular first molar crowns. MATERIAL AND METHODS An intraoral scanner was used to scan complete arch digital casts and to record patient-specific motion of 11 participants. Right and left mandibular first molars were selected as the target teeth. The complete crown preparations of the target teeth were virtually prepared on the digital mandibular casts by using the Geomagic Studio 2013 software program. High points were created by elevating the wear facets of the target teeth by 0.3 mm in the occlusal direction to generate digital wax patterns. The Dental System software program was used to design crowns with the anatomic coping design method. Occlusal adjustment with static occlusion (STA crown), with the average-value virtual articulator (DYN crown), and with patient-specific motion (FUN crown) was carried out. The crowns adjusted with these 3 methods were compared with the original wear facets. The mean value and root mean square (RMS) of 3D deviation were measured. One-way ANOVA was used to analyze the influence of the occlusal surface design methods on the morphology of the wear facets (α=.05). RESULTS The STA crowns had the poorest results with the mean ±standard deviation 3D deviation value of 0.15 ±0.05 mm and RMS value of 0.19 ±0.04 mm. The best results occurred in the FUN group, with the mean ±standard deviation 3D deviation value of 0.05 ±0.06 mm and RMS value of 0.13 ±0.03 mm. Significant differences were found among the 3 groups (P<.01). Except for the RMS value between the STA and DYN groups, significant differences were found between groups from the pairwise comparisons. CONCLUSIONS The occlusal surface of the crowns designed by using the patient-specific motion recorded with the intraoral scanner had the best coincidence with the morphology of the wear facets on the original teeth.
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Affiliation(s)
- Linlin Li
- Doctoral student, Faculty of Prosthodontics, Center of Digital Dentistry, Peking University School and Hospital of Stomatology & National Engineering Laboratory for Digital and Material Technology of Stomatology & Research Center of Engineering and Technology for Digital Dentistry of Ministry of Health & Beijing Key Laboratory of Digital Stomatology, National Clinical Research Center for Oral Diseases, Beijing, PR China
| | - Hu Chen
- Attending Doctor, Faculty of Prosthodontics, Center of Digital Dentistry, Peking University School and Hospital of Stomatology & National Engineering Laboratory for Digital and Material Technology of Stomatology & Research Center of Engineering and Technology for Digital Dentistry of Ministry of Health & Beijing Key Laboratory of Digital Stomatology, National Clinical Research Center for Oral Diseases, Beijing, PR China
| | - Weiwei Li
- Postdoctoral, Faculty of Prosthodontics, Center of Digital Dentistry, Peking University School and Hospital of Stomatology & National Engineering Laboratory for Digital and Material Technology of Stomatology & Research Center of Engineering and Technology for Digital Dentistry of Ministry of Health & Beijing Key Laboratory of Digital Stomatology, National Clinical Research Center for Oral Diseases, Beijing, PR China
| | - Yong Wang
- Professor, Faculty of Prosthodontics, Center of Digital Dentistry, Peking University School and Hospital of Stomatology & National Engineering Laboratory for Digital and Material Technology of Stomatology & Research Center of Engineering and Technology for Digital Dentistry of Ministry of Health & Beijing Key Laboratory of Digital Stomatology, National Clinical Research Center for Oral Diseases, Beijing, PR China
| | - Yuchun Sun
- Professor, Faculty of Prosthodontics, Center of Digital Dentistry, Peking University School and Hospital of Stomatology & National Engineering Laboratory for Digital and Material Technology of Stomatology & Research Center of Engineering and Technology for Digital Dentistry of Ministry of Health & Beijing Key Laboratory of Digital Stomatology, National Clinical Research Center for Oral Diseases, Beijing, PR China.
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Li L, Chen H, Wang Y, Sun Y. Construction of virtual intercuspal occlusion: Considering tooth displacement. J Oral Rehabil 2021; 48:701-710. [PMID: 33486815 DOI: 10.1111/joor.13153] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Revised: 11/30/2020] [Accepted: 01/14/2021] [Indexed: 11/29/2022]
Abstract
Common impressions cannot accurately duplicate the dental occlusion under occlusal force due to tooth displacement and mandibular deformation. To establish new methods to construct virtual intercuspal occlusion and assess their construction accuracy. The intraoral occlusal contacts of posterior teeth of 15 subjects were recorded with 8 μm and 100 μm articulating paper, respectively, and the marked teeth and buccal bite data were scanned with an intraoral scanner. The virtual dental occlusions were separately determined by buccal bite registration (BBR) method, and 3 new methods, namely segmented tooth registration (STR), occlusal contact areas (marked by 8 μm articulating paper) registration (OCR) and mixing registration (MR) methods. With the intraoral contact areas marked by 100 μm articulating paper set as reference and contact areas of the 4 virtual occlusions as tests, sensitivity, positive predictive value (PPV) and the ratio of overlapping areas were calculated. Kruskal-Wallis test or 1-way ANOVA was used to analyse the difference among groups. The sensitivity ranged from 0.69 to 0.94 and the PPV from 0.67 to 0.90. Sensitivity of OCR group and PPV of STR and OCR groups were different from that of BBR group at overlapping threshold of 50% (P = .028, .028 and .006). There was statistical difference of the ratio of overlapping areas over reference areas, and the values of STR and OCR groups were higher than that of BBR group (P = .045 and .021). The ability of STR and OCR methods to construct virtual intercuspal occlusion was better than BBR method.
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Affiliation(s)
- Linlin Li
- Faculty of Prosthodontics, Center of Digital Dentistry, Peking University School and Hospital of Stomatology & National Engineering Laboratory for Digital and Material Technology of Stomatology & Research Center of Engineering and Technology for Digital Dentistry of Ministry of Health & Beijing Key Laboratory of Digital Stomatology & National Clinical Research Center for Oral Diseases, Beijing, China
| | - Hu Chen
- Faculty of Prosthodontics, Center of Digital Dentistry, Peking University School and Hospital of Stomatology & National Engineering Laboratory for Digital and Material Technology of Stomatology & Research Center of Engineering and Technology for Digital Dentistry of Ministry of Health & Beijing Key Laboratory of Digital Stomatology & National Clinical Research Center for Oral Diseases, Beijing, China
| | - Yong Wang
- Faculty of Prosthodontics, Center of Digital Dentistry, Peking University School and Hospital of Stomatology & National Engineering Laboratory for Digital and Material Technology of Stomatology & Research Center of Engineering and Technology for Digital Dentistry of Ministry of Health & Beijing Key Laboratory of Digital Stomatology & National Clinical Research Center for Oral Diseases, Beijing, China
| | - Yuchun Sun
- Faculty of Prosthodontics, Center of Digital Dentistry, Peking University School and Hospital of Stomatology & National Engineering Laboratory for Digital and Material Technology of Stomatology & Research Center of Engineering and Technology for Digital Dentistry of Ministry of Health & Beijing Key Laboratory of Digital Stomatology & National Clinical Research Center for Oral Diseases, Beijing, China
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Guastaldi FPS, Martini AP, Rocha EP, Hochuli-Vieira E, Guastaldi AC. Ti-15Mo Alloy Decreases the Stress Concentration in Mandibular Angle Fracture Internal Fixation Hardware. J Maxillofac Oral Surg 2020; 19:314-320. [PMID: 32346246 DOI: 10.1007/s12663-019-01251-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Accepted: 05/29/2019] [Indexed: 10/26/2022] Open
Abstract
Objectives Comparison of the mechanical stability of 2.0 plates made of commercially pure titanium (cpTi) and a titanium-molybdenum (Ti-15Mo) alloy and two methods of internal fixation employed mandibular angle fractures, using 3D finite element analysis. Materials and Methods Four groups were evaluated. For the cpTi: group Eng 1P, one 4-hole plate and 4 screws 6 mm long, in the tension zone of the mandible; group Eng 2P, two 4-hole plates, one in the tension zone of the mandible and the other in the compression zone, both were fixed with 8 screws 6 mm long. The same groups were created for the Ti-15Mo alloy. A 100 N compressive load was applied to the occlusal surface of the mandibular first molar on the plated side. Results When considering the von Mises equivalent stress (σ vM) values for the comparison between both groups with one plate, a decrease of 10.5% in the plate and a decrease of 29.0% in the screws for the Ti-15Mo group was observed. Comparing the same groups with two plates, a decrease of 28.5% in the screws was shown for the Ti-15Mo alloy group. No significant differences were observed when considering maximum and minimum principal stresses (σ max, σ min), and maximum principal strain (ε max) to the mandibular bone. The Ti-15Mo alloy plates substantially decreased the stress concentration in the screws for both internal fixation techniques and in the plate for the Ti-15Mo 1 plate group. Conclusion From a clinical standpoint, the use of Ti-Mo alloy with reduced stiffness will decrease the stress shielding between the hardware and bone, influencing the outcome of the treatment.
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Affiliation(s)
- F P S Guastaldi
- 1Department of Diagnosis and Surgery, School of Dentistry, São Paulo State University (Unesp), Humaitá Street, 1680, Araraquara, SP 14801-903 Brazil
| | - A P Martini
- 2Department of Dental Materials and Prosthodontics, School of Dentistry, São Paulo State University (Unesp), Araçatuba, SP Brazil
| | - E P Rocha
- 2Department of Dental Materials and Prosthodontics, School of Dentistry, São Paulo State University (Unesp), Araçatuba, SP Brazil
| | - E Hochuli-Vieira
- 1Department of Diagnosis and Surgery, School of Dentistry, São Paulo State University (Unesp), Humaitá Street, 1680, Araraquara, SP 14801-903 Brazil
| | - A C Guastaldi
- 3Department of Physical Chemistry, Institute of Chemistry, São Paulo State University (Unesp), Araraquara, SP Brazil
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Accuracy of full-arch digital impressions: an in vitro and in vivo comparison. Clin Oral Investig 2019; 24:735-745. [DOI: 10.1007/s00784-019-02965-2] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Accepted: 05/16/2019] [Indexed: 10/26/2022]
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12
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Zhang H, Cui JW, Lu XL, Wang MQ. Finite element analysis on tooth and periodontal stress under simulated occlusal loads. J Oral Rehabil 2017; 44:526-536. [PMID: 28370179 DOI: 10.1111/joor.12512] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/26/2017] [Indexed: 11/28/2022]
Abstract
The tooth stress elicited by occluding contact represents critical biomechanical information about dental health during chewing. Effects of occlusal contact on tooth stress remain obscure. In this study, a mandibular first molar finite element model was built from CT images. The effects of area size, location and direction of occlusal loading on both tooth and periodontal stresses were analysed. Results showed tooth and periodontal stress had drastically different patterns. Tooth stress value was much higher than periodontal stress value under the same task. Tooth stress concentration area and its value decreased from outside to inside. The Maximum Tooth Stress (MTS) always occurred at the loading site and a larger loading area elicited a smaller MTS value. The variation of MTS was larger when the fossa bottoms were inclined loaded than when the cusp tips were inclined loaded, larger when lingually loaded than when buccally loaded and larger when mesially loaded than when distally loaded. Distal loadings generally induced smaller Maximum Periodontal Stress (MPS) variations than the mesial loadings. These findings indicated exposure of the rational site(s) to occlusal contact should be helpful to achieve proper tooth and periodontal stress, thus to diminish loading associated structure problems.
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Affiliation(s)
- H Zhang
- State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi International Joint Research Center for Oral Diseases, Department of Oral Anatomy and Physiology and TMD, School of Stomatology, The Fourth Military Medical University, Xi'an, China
| | - J-W Cui
- College of Automation, Harbin Engineering University, Harbin, China
| | - X L Lu
- Department of Mechanical Engineering, University of Delaware, Newark, DE, USA
| | - M-Q Wang
- State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi International Joint Research Center for Oral Diseases, Department of Oral Anatomy and Physiology and TMD, School of Stomatology, The Fourth Military Medical University, Xi'an, China
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Yang HM, Cha JY, Hong KS, Park JT. Three-dimensional finite element analysis of unilateral mastication in malocclusion cases using cone-beam computed tomography and a motion capture system. J Periodontal Implant Sci 2016; 46:96-106. [PMID: 27127690 PMCID: PMC4848384 DOI: 10.5051/jpis.2016.46.2.96] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2015] [Accepted: 02/27/2016] [Indexed: 11/23/2022] Open
Abstract
Purpose Stress distribution and mandible distortion during lateral movements are known to be closely linked to bruxism, dental implant placement, and temporomandibular joint disorder. The present study was performed to determine stress distribution and distortion patterns of the mandible during lateral movements in Class I, II, and III relationships. Methods Five Korean volunteers (one normal, two Class II, and two Class III occlusion cases) were selected. Finite element (FE) modeling was performed using information from cone-beam computed tomographic (CBCT) scans of the subjects’ skulls, scanned images of dental casts, and incisor movement captured by an optical motion-capture system. Results In the Class I and II cases, maximum stress load occurred at the condyle of the balancing side, but, in the Class III cases, the maximum stress was loaded on the condyle of the working side. Maximum distortion was observed on the menton at the midline in every case, regardless of loading force. The distortion was greatest in Class III cases and smallest in Class II cases. Conclusions The stress distribution along and accompanying distortion of a mandible seems to be affected by the anteroposterior position of the mandible. Additionally, 3-D modeling of the craniofacial skeleton using CBCT and an optical laser scanner and reproduction of mandibular movement by way of the optical motion-capture technique used in this study are reliable techniques for investigating the masticatory system.
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Affiliation(s)
- Hun-Mu Yang
- Department of Anatomy, Dankook University College of Medicine, Cheonan, Korea
| | - Jung-Yul Cha
- Department of Orthodontics, Yonsei University College of Dentistry, Seoul, Korea
| | - Ki-Seok Hong
- Perio-Implant Research Center, Dankook University College of Dentistry, Cheonan, Korea
| | - Jong-Tae Park
- Department of Oral Anatomy, Dankook University College of Dentistry, Cheonan, Korea
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