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Wang H, Chen H, Tian S, Sun Y, Wu F. Quantitative evaluation of the proximal contact area gap change characterization under intercuspal occlusion by intraoral 3D scanning: Food impaction with tight proximal contact. J ESTHET RESTOR DENT 2024; 36:1258-1266. [PMID: 38634200 DOI: 10.1111/jerd.13240] [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: 01/11/2024] [Revised: 03/22/2024] [Accepted: 04/10/2024] [Indexed: 04/19/2024]
Abstract
OBJECTIVE This study aimed to present three indicators that represent the proximal contact area gap change under intercuspal occlusion and to see if and how these indicators influence food impaction with tight proximal contact. MATERIALS AND METHODS Ninety volunteers were recruited for bite force measurement and intraoral scanning. Three-dimensional surface data and buccal bite data were obtained for 60 impacted and 60 non-impacted teeth. The scanning data were imported into the Geomagic Studio 2013 to measure three indicators, which included the gap change maximum (Δdm, μm), the buccolingual position of Δdm (P), and the gap expanded buccolingual range (S, mm). The difference between two groups of three indicators and their relationship with food impaction with tight proximal contact were analyzed by the t test, the Pearson chi-squared test, the nonparametric Mann-Whitney U test, and the binary logistic regression analysis (a = 0.05). RESULTS All indicators (Δdm, P, and S) were statistically different (p < 0.001, p = 0.002, and p < 0.001) in the impacted and non-impacted groups. Food impaction with tight proximal contact was affected by Δdm and S (p < 0.001, p = 0.039), but not by P (p = 0.409). CONCLUSION The excessive increase of the gap change maximum and the gap expanded buccolingual range under bite force promoted the occurrence of food impaction with tight proximal contact. CLINICAL SIGNIFICANCE The use of intraoral scanning to measure the characteristics of the proximal contact area gap change under bite force may help to deepen our understanding of the pathogenesis of food impaction with tight proximal contact. Importantly it can provide a reference basis for individualizing and quantifying occlusal adjustment treatment.
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Affiliation(s)
- Hongyan Wang
- Department of Prosthodontics, Shanxi Medical University School and Hospital of Stomatology, Taiyuan, People's Republic of China
| | - Hu Chen
- Center of Digital Dentistry, Faculty of Prosthodontics, Peking University School and Hospital of Stomatology, National Center for Stomatology, National Clinical Research Center for Oral Diseases, National Engineering Research Center of Oral Biomaterials and Digital Medical Devices, NHC Key Laboratory of Digital Stomatology, Beijing Key Laboratory of Digital Stomatology, Key Laboratory of Digital Stomatology, Chinese Academy of Medical Sciences, Beijing, People's Republic of China
| | - Sukun Tian
- Center of Digital Dentistry, Faculty of Prosthodontics, Peking University School and Hospital of Stomatology, National Center for Stomatology, National Clinical Research Center for Oral Diseases, National Engineering Research Center of Oral Biomaterials and Digital Medical Devices, NHC Key Laboratory of Digital Stomatology, Beijing Key Laboratory of Digital Stomatology, Key Laboratory of Digital Stomatology, Chinese Academy of Medical Sciences, Beijing, People's Republic of China
| | - Yuchun Sun
- Center of Digital Dentistry, Faculty of Prosthodontics, Peking University School and Hospital of Stomatology, National Center for Stomatology, National Clinical Research Center for Oral Diseases, National Engineering Research Center of Oral Biomaterials and Digital Medical Devices, NHC Key Laboratory of Digital Stomatology, Beijing Key Laboratory of Digital Stomatology, Key Laboratory of Digital Stomatology, Chinese Academy of Medical Sciences, Beijing, People's Republic of China
| | - Feng Wu
- Department of Prosthodontics, Shanxi Medical University School and Hospital of Stomatology, Taiyuan, People's Republic of China
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Oliveira PLE, Soares KEM, Andrade RMD, Oliveira GCD, Pithon MM, Araújo MTDS, Sant'anna EF. Stress and displacement of mini-implants and appliance in Mini-implant Assisted Rapid Palatal Expansion: analysis by finite element method. Dental Press J Orthod 2021; 26:e21203. [PMID: 34468562 PMCID: PMC8405139 DOI: 10.1590/2177-6709.26.4.e21203.oar] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Accepted: 05/24/2020] [Indexed: 11/21/2022] Open
Abstract
Objective: In this study, simulations were performed by the finite element method (FEM) to determine the tension and displacement in mini-implants and in expander appliance during rapid maxillary expansion, by varying the number and location of the mini-implants. Methods: For the computational simulation, a three-dimensional mesh was used for the maxilla, mini-implants and expander appliance. Comparisons were made on six different Mini-implant Assisted Rapid Palatal Expander (MARPE) configurations, by varying the amount and location of mini-implants. A closed suture was design and received two activations of 0.25 mm, and an open suture had a 0.5-mm aperture that received 20 activations, also of 0.25 mm. Results: For the closed suture, the maximum displacement values in the mini-implants were between 0.253 and 0.280 mm, and stress was between 1,348.9 and 2,948.2 MPa; in the expander appliance, the displacement values were between 0.256 and 0.281 mm, and stress was between 738.52 and 1,207.6 MPa. For the open suture, the maximum displacement values in the mini-implants were between 2.57 and 2.79 mm, and stress was between 5,765.3 and 10,366 MPa; in the appliance, the maximum displacements was between 2.53 and 2.89 mm, and stress was between 4,859.7 and 9,157.4 MPa. Conclusions: There were higher stress concentrations in the mini-implant than in the expander arm. In the simulations with a configuration of three mini-implants, stress overload was observed in the isolated mini-implant. Displacements of the mini-implants and arms of the appliance were similar in all simulations.
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Affiliation(s)
- Pedro Lima Emmerich Oliveira
- Universidade Federal do Rio de Janeiro, Departamento de Ortodontia e Odontologia Pediátrica (Rio de Janeiro/RJ, Brazil)
| | | | | | | | - Matheus Melo Pithon
- Universidade Estadual do Sudoeste da Bahia, Departamento de Ortodontia e Odontologia Pediátrica (Vitória da Conquista/BA, Brazil)
| | - Mônica Tirre de Souza Araújo
- Universidade Federal do Rio de Janeiro, Departamento de Ortodontia e Odontologia Pediátrica (Rio de Janeiro/RJ, Brazil)
| | - Eduardo Franzotti Sant'anna
- Universidade Federal do Rio de Janeiro, Departamento de Ortodontia e Odontologia Pediátrica (Rio de Janeiro/RJ, Brazil)
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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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Hasan LA, Al Qassar SSS, Alrawi MN, Alhajar EH. Does the flatting of the curve of spee affect the chewing force distribution in the mandible? (3D finite element study). J Orthod Sci 2021; 10:1. [PMID: 34084757 PMCID: PMC8102935 DOI: 10.4103/jos.jos_39_20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 07/25/2020] [Accepted: 07/31/2020] [Indexed: 11/25/2022] Open
Abstract
OBJECTIVE: To search the effects of Curve of Spee (COS) flatting on the stresses and displacement on the different mandible landmarks and lower teeth during posterior teeth loading using three-dimensional (3D) finite element analysis. MATERIALS AND METHODS: Three-dimensional hemi mandibular model was created from real selected mandible. The lower teeth was aligned originally in a curved form with 2.4 mm depth at the cusp tip of the second premolar. Another replica with flat aligned teeth was formed to confirm the analysis by up righting premolars and molars. A load was applied at mesio-buccal cusp of the lower first molar on both models, and the resultant stresses and displacements on the mandibular landmarks and the lower teeth were tested. RESULTS: Von mises over the mandible was higher in flat than in curve model. The highest stress levels were detected at the Mesio-buccal cusp tip of first molar for flat and curved simulation (5053, 3304) Mpa respectively. Mesio-distally, the teeth displacement was higher in curve model than in flat one. The maximum distal displacement, in flat model, was seen in central and lateral incisors. While, in curve model, the maximum distal displacement was grasped within first and second premolars. CONCLUSIONS: Flatting the COS magnify the stresses over whole mandible and reduce lower teeth displacement mesio-distally. We speculated that the readjustment of the COS after orthodontic treatment could reduce the stress and displacements on the lower anterior teeth and decrease the lower anterior teeth crowding relapse.
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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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de Brito GM, Brito HHDA, Marra GGM, Freitas LRP, Hargreaves BO, Magalhães PAA, Oliveira DD. Pure Mandibular Incisor Intrusion: A Finite Element Study to Evaluate the Segmented Arch Technique. MATERIALS (BASEL, SWITZERLAND) 2019; 12:ma12172784. [PMID: 31470584 PMCID: PMC6748075 DOI: 10.3390/ma12172784] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Revised: 08/19/2019] [Accepted: 08/19/2019] [Indexed: 06/10/2023]
Abstract
Leveling the curve of Spee is a commonly-used strategy to correct deep bites. Although several techniques have been proposed to intrude mandibular incisors (MI), flaring of these teeth is often observed and in many instances undesired. A three-dimensional (3D) finite element model (FEM) was used to locate the ideal point of force application (PFA) to achieve pure MI intrusion with the three-piece arches' technique. It comprised (1) a 0.021 × 0.025 in. stainless steel (SS) wire that passively filled the slots of the canine and premolar brackets and the first and second molar tubes, bilaterally; (2) a 0.0215 × 0.0275 in. SS intrusion base arch (IBA) inserted into the MI brackets, that presented a step down distal to the lateral incisors brackets and a posterior extension arm; (3) titanium-molybdenum tip-back springs designed to apply the intrusion force, fitted inside the first molar gingival tube. Four PFA on the IBA were simulated (FEM 1, 2, 3, and 4). FEM 3 resulted in pure MI and was considered the ideal PFA. FEM1 and 2 showed intrusion and buccal crown flaring of the MI, whereas FEM4 resulted in intrusion and lingual crown flaring of those teeth. Clinicians may consider three-piece arch mechanics to achieve pure MI intrusion. However, they must be aware that when force was applied anteriorly or posteriorly to the ideal PFA, the incisors would incline labially or lingually, respectively.
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Affiliation(s)
- Gabriela Meyge de Brito
- Department of Dentistry, Graduate Program in Orthodontics, Pontifical Catholic University of Minas Gerais, Belo Horizonte 30535-901, Brazil
| | - Hélio Henrique de Araújo Brito
- Department of Dentistry, Graduate Program in Orthodontics, Pontifical Catholic University of Minas Gerais, Belo Horizonte 30535-901, Brazil
| | - Gabriel Goulart Mendes Marra
- Department of Mechanical Engineering, Pontifical Catholic University of Minas Gerais, Belo Horizonte 30535-901, Brazil
| | - Laíze Rosa Pires Freitas
- Department of Dentistry, Graduate Program in Orthodontics, Pontifical Catholic University of Minas Gerais, Belo Horizonte 30535-901, Brazil
| | - Bernardo Oliveira Hargreaves
- Department of Mechanical Engineering, Pontifical Catholic University of Minas Gerais, Belo Horizonte 30535-901, Brazil
| | | | - Dauro Douglas Oliveira
- Department of Dentistry, Graduate Program in Orthodontics, Pontifical Catholic University of Minas Gerais, Belo Horizonte 30535-901, Brazil.
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Degirmenci K, Kocak-Buyukdere A, Ekici B. Evaluation of reliability of zirconia materials to be used in implant-retained restoration on the atrophic bone of the posterior maxilla: A finite element study. J Adv Prosthodont 2019; 11:112-119. [PMID: 31080572 PMCID: PMC6491356 DOI: 10.4047/jap.2019.11.2.112] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Revised: 03/11/2019] [Accepted: 03/12/2019] [Indexed: 11/08/2022] Open
Abstract
PURPOSE Zirconia materials have been used for implant-retained restorations, but the stress distribution of zirconia is not entirely clear. The aim of this study is to evaluate the stress distribution and risky areas caused by the different design of zirconia restorations on the atrophic bone of the posterior maxilla. MATERIALS AND METHODS An edentulous D4-type bone model was prepared from radiography of an atrophic posterior maxilla. Monolithic zirconia and zirconia-fused porcelain implant-retained restorations were designed as splinted or non-splinted. 300-N occlusal forces were applied obliquely. Stress analyses were performed using a 3D FEA program. RESULTS According to stress analysis, the bone between the 1) molar implant and the 2) premolar in the non-splinted monolithic zirconia restoration model was stated as the riskiest area. Similarly, the maximum von Mises stress value was detected on the bone of the non-splinted monolithic zirconia models. CONCLUSION Splinting of implant-retained restorations can be more critical for monolithic zirconia than zirconia fused to porcelain for the longevity of the bone.
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Affiliation(s)
- Kubra Degirmenci
- Department of Prosthodontics, Faculty of Dentistry, Bolu Abant Izzet Baysal University, Bolu, Turkey
| | - Ayse Kocak-Buyukdere
- Department of Prosthodontics, Faculty of Dentistry, Kocaeli University, Kocaeli, Turkey
| | - Bulent Ekici
- Department of Mechanical Engineering, Faculty of Engineering, Marmara University, Istanbul, Turkey
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Razaghi R, Biglari H, Karimi A. Dynamic finite element simulation of dental prostheses during chewing using muscle equivalent force and trajectory approaches. J Med Eng Technol 2017; 41:314-324. [PMID: 28351224 DOI: 10.1080/03091902.2017.1299231] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The long-term application of dental prostheses inside the bone has a narrow relation to its biomechanical performance. Chewing is the most complicated function of a dental implant as it implements different forces to the implant at various directions. Therefore, a suitable holistic modelling of the jaw bone, implant, food, muscles, and their forces would be deemed significant to figure out the durability as well as functionality of a dental implant while chewing. So far, two approaches have been proposed to employ the muscle forces into the Finite Element (FE) models, i.e. Muscle Equivalent Force (MEF) and trajectory. This study aimed at propounding a new three-dimensional dynamic FE model based on two muscle forces modelling approaches in order to investigate the stresses and deformations in the dental prosthesis as well as maxillary bone during the time of chewing a cornflakes bio. The results revealed that both contact and the maximum von Mises stress in the implant and bones for trajectory approach considerably exceed those of the MEF. The maximum stresses, moreover, are located around the neck of implant which should be both clinically and structurally strong enough to functionally maintain the bone-implant interface. In addition, a higher displacement due to compressive load is observed for the implant head in trajectory approach. The results suggest the benefits provided by trajectory approach since MEF approach would significantly underestimate the stresses and deformations in both the dental prosthesis and bones.
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Affiliation(s)
- Reza Razaghi
- a Mechanical Engineering Department , University of Tabriz , Tabriz , Iran
| | - Hasan Biglari
- a Mechanical Engineering Department , University of Tabriz , Tabriz , Iran
| | - Alireza Karimi
- b Research Department , Basir Eye Health Research Center , Tehran , Iran
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Panahandeh N, Torabzadeh H, Ziaee N, Mahdian M, Tootiaee B, Ghasemi A. The Effect of Composite Thickness on the Stress Distribution Pattern of Restored Premolar Teeth with Cusp Reduction. J Prosthodont 2015; 26:440-445. [PMID: 26646610 DOI: 10.1111/jopr.12422] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/16/2015] [Indexed: 11/27/2022] Open
Abstract
PURPOSE Different thicknesses of restorative material can alter the stress distribution pattern in remaining tooth structure. The assumption is that a thicker composite restoration will induce a higher fracture resistance. Therefore, the present study evaluated the effect of composite thickness on stress distribution in a restored premolar with cusp reduction. MATERIALS AND METHODS A 3D solid model of a maxillary second premolar was prepared and meshed. MOD cavities were designed with different cusp reduction thicknesses (0, 0.5, 1, 1.5, 2.5 mm). Cavities were restored with Valux Plus composite. They were loaded with 200 N force on the occlusal surface in the direction of the long axis. Von Mises stresses were evaluated with Abaqus software. RESULTS Stress increased from occlusal to gingival and was maximum in the cervical region. The stressed area in the palatal cusp was more than that of the buccal cusp. Increasing the thickness of composite altered the shear stress to compressive stress in the occlusal area of the teeth. CONCLUSION The model with 2.5 mm cusp reduction exhibited the most even stress distribution.
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Affiliation(s)
- Narges Panahandeh
- Dental Research Center, Research Institute of Dental Sciences, Dental School, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Hassan Torabzadeh
- Iranian Center for Endodontic Research, Research Institute of Dental Sciences, Dental School, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Nargess Ziaee
- Department of Periodontics, Dental School, Kermanshah University of Medical Sciences, Kermanshah, Iran
| | - Mina Mahdian
- Department of Prosthodontics and Digital Technology, Stony Brook, NY
| | - Bahman Tootiaee
- Dental Research Center, Research Institute of Dental Sciences, Dental School, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Amir Ghasemi
- Preventive Dentistry Research Center, Research Institute of Dental Sciences, Dental School, Shahid Beheshti University of Medical Sciences, Tehran, Iran
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Caballero GM, Carvalho Filho OAD, Hargreaves BO, Brito HHDA, Magalhães Júnior PAA, Oliveira DD. Mandibular canine intrusion with the segmented arch technique: A finite element method study. Am J Orthod Dentofacial Orthop 2015; 147:691-7. [PMID: 26038072 DOI: 10.1016/j.ajodo.2015.01.022] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2014] [Revised: 01/01/2015] [Accepted: 01/01/2015] [Indexed: 11/27/2022]
Abstract
INTRODUCTION Mandibular canines are anatomically extruded in approximately half of the patients with a deepbite. Although simultaneous orthodontic intrusion of the 6 mandibular anterior teeth is not recommended, a few studies have evaluated individual canine intrusion. Our objectives were to use the finite element method to simulate the segmented intrusion of mandibular canines with a cantilever and to evaluate the effects of different compensatory buccolingual activations. METHODS A finite element study of the right quadrant of the mandibular dental arch together with periodontal structures was modeled using SolidWorks software (Dassault Systèmes Americas, Waltham, Mass). After all bony, dental, and periodontal ligament structures from the second molar to the canine were graphically represented, brackets and molar tubes were modeled. Subsequently, a 0.021 × 0.025-in base wire was modeled with stainless steel properties and inserted into the brackets and tubes of the 4 posterior teeth to simulate an anchorage unit. Finally, a 0.017 × 0.025-in cantilever was modeled with titanium-molybdenum alloy properties and inserted into the first molar auxiliary tube. Discretization and boundary conditions of all anatomic structures tested were determined with HyperMesh software (Altair Engineering, Milwaukee, Wis), and compensatory toe-ins of 0°, 4°, 6°, and 8° were simulated with Abaqus software (Dassault Systèmes Americas). RESULTS The 6° toe-in produced pure intrusion of the canine. The highest amounts of periodontal ligament stress in the anchor segment were observed around the first molar roots. This tooth showed a slight tendency for extrusion and distal crown tipping. Moreover, the different compensatory toe-ins tested did not significantly affect the other posterior teeth. CONCLUSIONS The segmented mechanics simulated in this study may achieve pure mandibular canine intrusion when an adequate amount of compensatory toe-in (6°) is incorporated into the cantilever to prevent buccal and lingual crown tipping. The effects on the posterior anchorage segment were small and initially concentrated on the first molar.
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Affiliation(s)
| | - Osvaldo Abadia de Carvalho Filho
- Postgraduate student, Department of Mechanical Engineering, Pontifical Catholic University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Bernardo Oliveira Hargreaves
- Postgraduate student, Department of Mechanical Engineering, Pontifical Catholic University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Hélio Henrique de Araújo Brito
- Associate professor, Department of Orthodontics, Pontifical Catholic University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Pedro Américo Almeida Magalhães Júnior
- Associate professor and program director, Department of Mechanical Engineering, Pontifical Catholic University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Dauro Douglas Oliveira
- Associate professor and program director, Department of Orthodontics, Pontifical Catholic University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil.
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De Oliveira BF, Seraidarian PI, de Oliveira SG, Landre J, Pithon MM, Oliveira DD. Tooth displacement in shortened dental arches: A three-dimensional finite element study. J Prosthet Dent 2014; 111:460-5. [DOI: 10.1016/j.prosdent.2013.07.022] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2012] [Revised: 07/25/2013] [Accepted: 07/26/2013] [Indexed: 10/25/2022]
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Guerrero CA, Marin D, Galvis AI. Evolución de la patología oclusal. Una revisión de la literatura. JOURNAL OF ORAL RESEARCH 2013. [DOI: 10.17126/joralres.2013.017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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Shahrbaf S, vanNoort R, Mirzakouchaki B, Ghassemieh E, Martin N. Effect of the crown design and interface lute parameters on the stress-state of a machined crown-tooth system: a finite element analysis. Dent Mater 2013; 29:e123-31. [PMID: 23706694 DOI: 10.1016/j.dental.2013.04.002] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2012] [Revised: 12/21/2012] [Accepted: 04/05/2013] [Indexed: 11/30/2022]
Abstract
The effect of preparation design and the physical properties of the interface lute on the restored machined ceramic crown-tooth complex are poorly understood. The aim of this work was to determine, by means of three-dimensional finite element analysis (3D FEA) the effect of the tooth preparation design and the elastic modulus of the cement on the stress state of the cemented machined ceramic crown-tooth complex. The three-dimensional structure of human premolar teeth, restored with adhesively cemented machined ceramic crowns, was digitized with a micro-CT scanner. An accurate, high resolution, digital replica model of a restored tooth was created. Two preparation designs, with different occlusal morphologies, were modeled with cements of 3 different elastic moduli. Interactive medical image processing software (mimics and professional CAD modeling software) was used to create sophisticated digital models that included the supporting structures; periodontal ligament and alveolar bone. The generated models were imported into an FEA software program (hypermesh version 10.0, Altair Engineering Inc.) with all degrees of freedom constrained at the outer surface of the supporting cortical bone of the crown-tooth complex. Five different elastic moduli values were given to the adhesive cement interface 1.8GPa, 4GPa, 8GPa, 18.3GPa and 40GPa; the four lower values are representative of currently used cementing lutes and 40GPa is set as an extreme high value. The stress distribution under simulated applied loads was determined. The preparation design demonstrated an effect on the stress state of the restored tooth system. The cement elastic modulus affected the stress state in the cement and dentin structures but not in the crown, the pulp, the periodontal ligament or the cancellous and cortical bone. The results of this study suggest that both the choice of the preparation design and the cement elastic modulus can affect the stress state within the restored crown-tooth complex.
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Affiliation(s)
- Shirin Shahrbaf
- Academic Unit of Restorative Dentistry, The School of Clinical Dentistry, Claremont Crescent, Sheffield, UK.
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Shimizu Y, Ishida T, Hosomichi J, Kaneko S, Hatano K, Ono T. Soft diet causes greater alveolar osteopenia in the mandible than in the maxilla. Arch Oral Biol 2013; 58:907-11. [PMID: 23490352 DOI: 10.1016/j.archoralbio.2013.02.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2012] [Revised: 02/06/2013] [Accepted: 02/11/2013] [Indexed: 10/27/2022]
Abstract
OBJECTIVE To investigate changes in the bony microstructure of the upper and lower alveolar bone during masticatory loading induced by soft diet feeding in growing rats. DESIGN Three-week-old male Wistar rats were randomly divided into two groups. Rats were fed with either pellets [control group (n=6)] or a soft diet [experimental group (n=6)] for nine weeks. 3D-microstructure of the alveolar bone of the first molar region (M1) was examined by micro-CT analysis. RESULTS Micro-CT images showed increased marrow spaces of the inter-radicular alveolar bone around the rat mandibular M1 in the experimental group compared with that in the control group. The bone volume/tissue volume ratio, trabecular thickness, trabecular number, mean intercept length, trabecular width and trabecular star volume for the mandibular M1 inter-radicular alveolar bone were lower in the experimental group than in the control group. Marrow space star volume was increased in the experimental group compared with the control group. CONCLUSIONS These results suggest that alveolar osteopenia is more extensive in the mandible than the maxilla in rats that experience low masticatory loading during growth.
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Affiliation(s)
- Yasuhiro Shimizu
- Orthodontic Science, Department of Orofacial Development and Function, Division of Oral Health Sciences, Graduate School, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8549, Japan.
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Stress analysis in single molar tooth. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2013; 33:691-8. [PMID: 25427475 DOI: 10.1016/j.msec.2012.10.020] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2012] [Revised: 09/15/2012] [Accepted: 10/28/2012] [Indexed: 10/27/2022]
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Araugio RMDS, Landre J, Silva DDLA, Pacheco W, Pithon MM, Oliveira DD. Influence of the expansion screw height on the dental effects of the hyrax expander: A study with finite elements. Am J Orthod Dentofacial Orthop 2013; 143:221-7. [DOI: 10.1016/j.ajodo.2012.09.016] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2012] [Revised: 09/01/2012] [Accepted: 09/01/2012] [Indexed: 10/27/2022]
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Greco GD, Las Casas EBD, Cornacchia TPM, Magalhães CSD, Moreira AN. Standard of disocclusion in complete dentures supported by implants without free distal ends: analysis by the finite elements method. J Appl Oral Sci 2012; 20:64-9. [PMID: 22437680 PMCID: PMC3928774 DOI: 10.1590/s1678-77572012000100012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2009] [Accepted: 10/26/2010] [Indexed: 11/22/2022] Open
Abstract
OBJECTIVE The occlusal patterns are key requirements for the clinical success of oral rehabilitation supported by implants. This study compared the stresses generated by the disocclusion in the canine guide occlusion (CGO) and bilateral balanced occlusion (BBO) on the implants and metallic infrastructure of a complete Brånemark protocol-type denture modified with the inclusion of one posterior short implant on each side. MATERIAL AND METHODS A three-dimensional model simulated a mandible with seven titanium implants as pillars, five of them installed between the mental foramen and the two posterior implants, located at the midpoint of the occlusal surface of the first molar. A load of 15 N with an angle of 45° was applied to a tooth or distributed across three teeth to simulate the CGO or BBO, respectively. The commercial program ABAQUS® was used for the model development, before and after the processing of the data. The results were based on a linear static analysis and were used to compare the magnitude of the equivalent stress for each of the simulations. RESULTS The results showed that the disocclusion in CGO generated higher stresses concentrated on the working side in the region of the short implant. In BBO, the stresses were less intense and more evenly distributed on the prosthesis. The maximum stress found in the simulation of the disocclusion in CGO was two times higher than that found in the simulation of the BBO. The point of maximum stress was located in the neck of the short implant on the working side. CONCLUSIONS Under the conditions of this study, it was concluded that the BBO pattern was more suitable than CGO for the lower complete denture supported by implants without free distal ends.
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Affiliation(s)
- Gustavo Diniz Greco
- Dental School, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil.
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Cossetin E, Nóbrega SHSD, Carvalho MGFD. Study of tension in the periodontal ligament using the finite elements method. Dental Press J Orthod 2012. [DOI: 10.1590/s2176-94512012000100006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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Matsunaga S, Takano N, Tamatsu Y, Abe S, Ide Y. Biomechanics of Jaw Bone Considering Structural Properties of Trabecular Bone. J Oral Biosci 2011. [DOI: 10.1016/s1349-0079(11)80017-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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TAJIMA K, CHEN KK, TAKAHASHI N, NODA N, NAGAMATSU Y, KAKIGAWA H. Three-dimensional finite element modeling from CT images of tooth and its validation. Dent Mater J 2009; 28:219-26. [DOI: 10.4012/dmj.28.219] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Donovan TE, Becker W, Brodine AH, Burgess JO, Cagna DR, Summitt JB. Annual review of selected dental literature: report of the Committee on Scientific Investigation of the American Academy of Restorative Dentistry. J Prosthet Dent 2008; 100:110-41. [PMID: 18672128 DOI: 10.1016/s0022-3913(08)60159-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- Terence E Donovan
- Department of Operative Dentistry, University of North Carolina, Chapel Hill, NC 27599-7450, USA. Terry_Donovan @dentistry.unc.edu
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