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Ananya, Rani P, Sinha T, Prakash J. Maxillary Cast Partial Denture and Mandibular Implant-Supported Metal-Ceramic Prosthesis With a Split Framework to Compensate for Mandibular Flexure: A Case Report. Cureus 2023; 15:e49071. [PMID: 38130512 PMCID: PMC10733657 DOI: 10.7759/cureus.49071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/17/2023] [Indexed: 12/23/2023] Open
Abstract
The goal of modern dentistry is to restore optimum oral health, function, and comfort for a patient. For an implant-supported fixed prosthesis, these goals cannot be met if the biomechanical factors governing the success of the prosthesis are overlooked. Mandibular flexure is one such factor that needs to be considered, especially when implants are being placed posterior to the interforaminal region. If not, it can lead to problems like increased stress, bone resorption, poor fit of the prosthesis, screw loosening, and patient discomfort. The use of a split-framework prosthesis is one of the measures that could be taken to decrease the stress, ensure a passive fit of the framework, and long-term maintenance of patient comfort and function. This case report describes the oral rehabilitation of a patient using a maxillary cast partial denture and mandibular split framework fixed prosthesis to compensate for mandibular flexure.
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Affiliation(s)
- Ananya
- Prosthodontics, Rajendra Institute of Medical Sciences, Ranchi, IND
| | - Priya Rani
- Prosthodontics, Rajendra Institute of Medical Sciences, Ranchi, IND
| | - Tushar Sinha
- Prosthodontics, Rajendra Institute of Medical Sciences, Ranchi, IND
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Gao J, Jiang L, Zhao B. Median mandibular flexure-the unique physiological phenomenon of the mandible and its clinical significance in implant restoration. Front Bioeng Biotechnol 2023; 11:1238181. [PMID: 37744259 PMCID: PMC10513439 DOI: 10.3389/fbioe.2023.1238181] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2023] [Accepted: 08/29/2023] [Indexed: 09/26/2023] Open
Abstract
Mandibular flexure, characterized by unique biomechanical behaviors such as elastic bending and torsion under functional loading, has emerged as a crucial factor in oral clinical diagnosis and treatment. This paper presents a comprehensive review of the current research status on mandibular flexure, drawing insights from relevant studies retrieved from the PubMed database (www.ncbi.nlm.nih.gov/pubmed), including research conclusions, literature reviews, case reports, and authoritative reference books. This paper thoroughly explores the physiological mechanisms underlying mandibular flexure, discussing different concurrent deformation types and the essential factors influencing this process. Moreover, it explores the profound implications of mandibular flexure on clinical aspects such as bone absorption around dental implants, the precision of prosthesis fabrication, and the selection and design of superstructure materials. Based on the empirical findings, this review provides crucial clinical recommendations. Specifically, it is recommended to exert precise control over the patients mouth opening during impression-taking. Those with a high elastic modulus or bone-tissue-like properties should be prioritized when selecting superstructure materials. Moreover, this review underscores the significance of customizing framework design to accommodate individual variations in facial morphology and occlusal habits. Future research endeavors in this field have the potential to advance clinical diagnosis and treatment approaches, providing opportunities for improvement.
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Affiliation(s)
| | | | - Baohong Zhao
- Center of Implantology School and Hospital of Stomatology, China Medical University, Liaoning Province Key Laboratory of Oral Diseases, Shenyang, China
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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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Mijiritsky E, Shacham M, Meilik Y, Dekel-Steinkeller M. Clinical Influence of Mandibular Flexure on Oral Rehabilitation: Narrative Review. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:16748. [PMID: 36554629 PMCID: PMC9778818 DOI: 10.3390/ijerph192416748] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Revised: 12/11/2022] [Accepted: 12/12/2022] [Indexed: 06/17/2023]
Abstract
AIM The current paper aims to review mandibular flexure and its clinical implications in the field of oral rehabilitation. Mandibular flexure is a deformity of the mandible, which occurs during jaw movements. METHODS AND MATERIALS An electronic database search was conducted using the PRISM model, with a total of 49 articles included. RESULTS Mandibular flexure affects various stages of oral rehabilitation treatments. Effects of mandibular flexure are more significant in periodontal patients, and in implant-supported restorations, compared to natural teeth, due to differences in the force absorption by the periodontal ligament. Various adjustments must be made to the prosthodontic framework to enable long-term survival of the restorative treatments. CONCLUSIONS Dental practitioners should pay attention to the following: (1) digital impressions are preferred over conventional; (2) mouth opening should be kept to a minimum (as possible, up to 10-20 mm) while also avoiding any anterior movements of the mandible (protrusion); (3) the number of abutment teeth should be kept to a minimum; (4) structures in the lower jaw should be splitted; (5) non-rigid connectors should be used to reduce the effort exerted; (6) in periodontal patients, the preference is for short-span restorations and non-rigid connectors; (7) in implant-supported restorations, it is preferable to divide the framework into two or three segments, utilizing rigid materials with a low elastic modulus. There is no agreement in the literature about the preferred location of the implants in the jaw.
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Affiliation(s)
- Eitan Mijiritsky
- The Maurice and Gabriela Goldschleger School of Dental Medicine, Tel Aviv University, Tel Aviv 6997801, Israel
- Department of Otolaryngology, Head and Neck and Maxillofacial Surgery, Tel-Aviv Sourasky Medical Center, Sackler Faculty of Medicine, Tel Aviv 6139001, Israel
| | - Maayan Shacham
- School of Social Work, Ariel University, Ariel 40700, Israel
| | - Yuval Meilik
- The Maurice and Gabriela Goldschleger School of Dental Medicine, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Michal Dekel-Steinkeller
- The Maurice and Gabriela Goldschleger School of Dental Medicine, Tel Aviv University, Tel Aviv 6997801, Israel
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Gao J, Li X, He J, Jiang L, Zhao B. The effect of mandibular flexure on the design of implant-supported fixed restorations of different facial types under two loading conditions by three-dimensional finite element analysis. Front Bioeng Biotechnol 2022; 10:928656. [PMID: 36105608 PMCID: PMC9465293 DOI: 10.3389/fbioe.2022.928656] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Accepted: 07/22/2022] [Indexed: 11/13/2022] Open
Abstract
Objective: Investigating the biomechanical effects of mandibular flexure (MF) on the design of implant-supported fixed restorations in edentulous jaws of different facial types. Methods: Three-dimensional finite element models were established to analyze mandibular displacement and stress distribution of implant-supported fixed restorations (four or six implants, different implant numbers and sites, and the design of the superstructure across the dental arch in one or two or three pieces, under the loading conditions of maximum opening or right unilateral molar occlusion) in mandibular edentulous patients of three different facial types (brachyfacial, mesofacial, and dolichofacial types). Results: The brachyfacial type presented higher mandibular flexure and stress in the overall restorative system, followed by the mesofacial and dolichofacial types. During jaw opening and occlusal movements, the one-piece framework showed the lowest bone stress values surrounding the anterior implants and gradually increased to the distal position, and the three-piece framework showed the highest stress values for peri-implant bones. Also, the split framework could greatly increase the stress on abutments and frameworks. Moreover, fixed implant prostheses with cantilevers can generate high amounts of biomechanical stress and strain on implants and surrounding bones. The bone surrounding the anterior implant increased in stress values as the most distal implants were more distally located regardless of frameworks. The zirconia framework demonstrated higher stresses than the titanium framework. Conclusion: The design of edentulous fixed implant-supported restorations can be optimized for facial types. For patients of the brachyfacial type or with high masticatory muscle strength, the non-segmented framework without a cantilever provides an optimal biomechanical environment.
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Affiliation(s)
- Jing Gao
- Center of Implantology School and Hospital of Stomatology, China Medical University, Liaoning Province Key Laboratory of Oral Diseases, Shenyang, China
| | - Xuejing Li
- Shanghai Engineering Research Center of Tooth Restoration and Regeneration, Department of Prosthodontics, School and Hospital of Stomatology, Tongji University, Shanghai, China
| | - Jing He
- Center of Implantology School and Hospital of Stomatology, China Medical University, Liaoning Province Key Laboratory of Oral Diseases, Shenyang, China
| | - Lulu Jiang
- Center of Implantology School and Hospital of Stomatology, China Medical University, Liaoning Province Key Laboratory of Oral Diseases, Shenyang, China
- *Correspondence: Lulu Jiang, ; Baohong Zhao,
| | - Baohong Zhao
- Center of Implantology School and Hospital of Stomatology, China Medical University, Liaoning Province Key Laboratory of Oral Diseases, Shenyang, China
- *Correspondence: Lulu Jiang, ; Baohong Zhao,
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Greenbaum T, Pitance L, Kedem R, Emodi-Perlman A. The mouth-opening muscular performance in adults with and without temporomandibular disorders: A systematic review. J Oral Rehabil 2022; 49:476-494. [PMID: 35020217 PMCID: PMC9303535 DOI: 10.1111/joor.13303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2021] [Revised: 12/20/2021] [Accepted: 01/04/2022] [Indexed: 11/30/2022]
Abstract
Background The mouth‐opening muscular performance in patients with temporomandibular disorders (TMDs) is unclear. Understanding the impairments of this muscle group within specific TMDs is important to develop proper management strategies. Objective To characterise the mouth‐opening muscular performance in adults with and without TMDs. Methods PubMed, EMBASE, CINAHL, Scopus, Web of Science and Cochrane databases were searched from inception to 12 November 2020. Bibliographies were searched for additional articles, including grey literature. Case‐control, cross‐sectional and interventional studies reporting mouth‐opening muscular strength and/or endurance were included. Risk of bias was assessed by the SIGN checklist for case‐control studies and by the NIH quality assessment tool for cross‐sectional studies. Results were pooled with a random‐effects model. Confidence in cumulative evidence was determined by means of the GRADE guidelines. Results Fourteen studies were included; most were rated as having a moderate risk of bias. Only three studies assessed patients with TMDs and the other 11 assessed healthy adults. Significant sex differences in muscular performance were found for healthy adults in the review (strength deficit for females versus males). There was a significant reduction in maximal mouth opening performance (strength and endurance) in the three studies that assessed patients with temporomandibular disorders. Conclusion Sex plays a significant role in maximal mouth opening strength. There is a lack of reliable data on the normal mouth‐opening strength and endurance of healthy adults as well as for patients with TMDs. Implications Lack of reliable TMDs patient data and comparable healthy adult data highlight future direction for research.
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Affiliation(s)
- Tzvika Greenbaum
- Department of Physical Therapy, Faculty of Health Sciences, Recanati School for Community Health Professions, Ben-Gurion University of the Negev, Beer Sheva, Israel
| | - Laurent Pitance
- Institute of Experimental and Clinical Research, Health Sciences division, Neuro-Musculo-Skeletal-Lab (NMSK), Université Catholique de Louvain, Brussels, Belgium
| | - Ron Kedem
- Academic Branch, Medical Corps, IDF, Tel Aviv, Israel
| | - Alona Emodi-Perlman
- The School of Dental Medicine, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
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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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Thongpoung S, Masaki C, Nodai T, Munemasa T, Mukaibo T, Kondo Y, Hosokawa R. A new mandibular deformation index predicts amount of bone deformation in edentulous patients treated with an implant-supported fixed prosthesis. J Prosthodont Res 2021; 66:582-588. [PMID: 34924491 DOI: 10.2186/jpr.jpr_d_21_00145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
PURPOSE The present study was performed to examine the mandibular deformation during mouth opening in edentulous patients, treated with an implant-supported fixed prosthesis using strain gauges, and identify factors affecting deformation. METHODS Twenty patients with a fully edentulous mandible who received either 4 or ≥6 implants were included. The distal-most implants were placed mesial to the mental foramen (premolar region) in patients with 4 implants and distal to the mental foramen (molar region) in patients with ≥6 implants. Mandibular deformation during mouth opening was measured using strain gauges in two directions: anteroposterior direction and lateral direction between the distal-most implants on the left and right sides (arch width). The mandibular anatomy was evaluated using computed tomography. RESULTS Arch width reduction between the left and right implants during mouth opening ranged from 47.38 to 512.80 µm; the range of deformation was 0.12 to 15.14 µm in the anteroposterior direction. Furthermore, a significant positive correlation was noted between arch width reduction in the premolar region and the ratio between the symphyseal bone height and width (P = 0.0003, r = 0.72). CONCLUSION The reduction in arch width was higher in the molar region than in the premolar region during mouth opening. Moreover, the reduction could be high in the mandibular symphyseal bone because of its greater height and lesser width. The ratio between the symphyseal bone height and width is defined as the mandibular deformation index (MDI) and is used to predict the rate of mandibular bone deformation.
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Affiliation(s)
- Sirapat Thongpoung
- Division of Oral Reconstruction and Rehabilitation, Kyushu Dental University Graduate School, Japan.,Department of Prosthodontics, College of Dental Medicine, Rangsit University, Pathum Thani, Thailand
| | - Chihiro Masaki
- Division of Oral Reconstruction and Rehabilitation, Kyushu Dental University Graduate School, Japan
| | - Tomotaka Nodai
- Division of Oral Reconstruction and Rehabilitation, Kyushu Dental University Graduate School, Japan
| | - Takashi Munemasa
- Division of Oral Reconstruction and Rehabilitation, Kyushu Dental University Graduate School, Japan
| | - Taro Mukaibo
- Division of Oral Reconstruction and Rehabilitation, Kyushu Dental University Graduate School, Japan
| | - Yusuke Kondo
- Division of Oral Reconstruction and Rehabilitation, Kyushu Dental University Graduate School, Japan
| | - Ryuji Hosokawa
- Division of Oral Reconstruction and Rehabilitation, Kyushu Dental University Graduate School, Japan
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Iwauchi Y, Tanaka S, Kamimura-Sugimura E, Baba K. Clinical evaluation of the precision of interocclusal registration by using digital and conventional techniques. J Prosthet Dent 2021; 128:611-617. [PMID: 33775391 DOI: 10.1016/j.prosdent.2021.01.021] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Revised: 01/17/2021] [Accepted: 01/19/2021] [Indexed: 11/16/2022]
Abstract
STATEMENT OF PROBLEM Although studies have evaluated the accuracy of data obtained by intraoral scanners (IOSs), studies on the precision of interocclusal registrations made with IOSs are lacking. PURPOSE The purpose of this clinical study was to compare the precision of IOS interocclusal registration with that of conventional methods with a silicone impression material and a gypsum cast. MATERIAL AND METHODS Eight participants with complete natural dentitions were enrolled. Images of their maxillary and mandibular quadrant arches and their interocclusal relationship were scanned with 2 IOSs: the 3M True Definition Scanner and the TRIOS Scanner 3. In the conventional method, impressions of complete-arch dentition and quadrant-arch dentition were made with a silicone impression material, and gypsum casts were fabricated, mounted on a dental articulator related with a silicone interocclusal record, and scanned with a 3D laboratory scanner. These procedures were repeated 4 times, and 4 sets of interocclusal registration data in standard tessellation language (STL) format were generated for each condition. Interocclusal registration precision was evaluated by determining the discrepancy of the STL data between repeated measurements by using the best-fit-algorithm method. RESULTS The average discrepancies for all participants were 25 ±12 μm for the True Definition, 31 ±7 μm for the TRIOS 3, 154 ±59 μm for the complete arch, and 128 ±33 μm for the quadrant arch. The Kruskal-Wallis test revealed that the effect of the impression methods on the discrepancy was statistically significant (P<.001). The Steel-Dwass test showed that both digital scan methods exhibited significantly smaller discrepancies than the 2 conventional methods (P=.005). CONCLUSIONS These results suggest that the intermaxillary relationship captured by the digital scan method by using IOSs had better precision than that obtained by the conventional method.
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Affiliation(s)
- Yotaro Iwauchi
- Predoctoral student, Department of Prosthodontics, School of Dentistry, Showa University, Tokyo, Japan
| | - Shinpei Tanaka
- Assistant Professor, Department of Prosthodontics, School of Dentistry, Showa University, Tokyo, Japan
| | - Emi Kamimura-Sugimura
- Lecturer, Department of Oral Microbiology and Immunology, School of Dentistry, Showa University, Tokyo, Japan
| | - Kazuyoshi Baba
- Professor and Chair, Department of Prosthodontics, School of Dentistry, Showa University, Tokyo, Japan.
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11
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Schmidt A, Klussmann L, Schlenz MA, Wöstmann B. Elastic deformation of the mandibular jaw revisited-a clinical comparison between digital and conventional impressions using a reference. Clin Oral Investig 2021; 25:4635-4642. [PMID: 33442777 PMCID: PMC8310469 DOI: 10.1007/s00784-021-03777-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Accepted: 01/04/2021] [Indexed: 11/27/2022]
Abstract
Objectives Due to the partly strongly differing results in the literature, the aim of the present study was to investigate a possible deformation of the mandible during mouth opening using an intraoral scanner (IOS) and a conventional impression for comparison with a reference aid. Materials and methods Four steel spheres were reversibly luted in the mandibular (n = 50) with a metallic reference aid at maximum mouth opening (MMO). Two digital impressions (Trios3), at MMO and at slightly mouth opening SMO and a conventional impression (Impregum), were taken as the measuring accuracy of the reference structure was already known. Difference between MMO-SMO for digital impressions and deviations between digital and conventional (SMO) were calculated. Furthermore, the angle between the normal vectors of two constructed planes was measured. Statistical analysis was performed with SPSS25. Results Deviations for linear distances ranged from −1 ± 3 μm up to 17 ± 78 μm (digital impressions, MMO-SMO), from 19 ± 16 μm up to 132 ± 90 μm (digital impressions, SMO), and from 28 ± 17 μm up to 60 ± 52 μm (conventional impressions, SMO). There were no significant differences for digital impressions (MMO-SMO), and there were significant differences between the conventional and digital impressions at SMO. Conclusions Based on the results of the present study, no mandibular deformation could be detected during mouth opening with regard to the digital impressions. The results were rather within the measuring tolerance of the intraoral scanner. Clinical relevance Based on the present study, no deformation of the mandibular during mouth opening could be observed at the level previously assumed. Therewith related, dental techniques related to a possible mandibular deformation therefore should be reconsidered.
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Affiliation(s)
- Alexander Schmidt
- Department of Prosthodontics, Dental Clinic, Justus Liebig University, Schlangenzahl 14, 35392, Giessen, Germany.
| | - Leona Klussmann
- Department of Prosthodontics, Dental Clinic, Justus Liebig University, Schlangenzahl 14, 35392, Giessen, Germany
| | - Maximiliane A Schlenz
- Department of Prosthodontics, Dental Clinic, Justus Liebig University, Schlangenzahl 14, 35392, Giessen, Germany
| | - Bernd Wöstmann
- Department of Prosthodontics, Dental Clinic, Justus Liebig University, Schlangenzahl 14, 35392, Giessen, Germany
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Bernauer SA, Müller J, Zitzmann NU, Joda T. Influence of Preparation Design, Marginal Gingiva Location, and Tooth Morphology on the Accuracy of Digital Impressions for Full-Crown Restorations: An In Vitro Investigation. J Clin Med 2020; 9:jcm9123984. [PMID: 33316958 PMCID: PMC7763051 DOI: 10.3390/jcm9123984] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Revised: 12/04/2020] [Accepted: 12/07/2020] [Indexed: 12/02/2022] Open
Abstract
(1) Background: Intraoral optical scanning (IOS) has gained increased importance in prosthodontics. The aim of this in vitro study was to analyze the IOS accuracy for treatment with full crowns, considering possible influencing factors. (2) Methods: Two tooth morphologies, each with four different finish-line designs for tooth preparation and epi- or supragingival locations, were digitally designed, 3D-printed, and post-processed for 16 sample abutment teeth. Specimens were digitized using a laboratory scanner to generate reference STLs (Standard Tessellation Language), and were secondary-scanned with two IOS systems five times each in a complete-arch model scenario (Trios 3 Pod, Primescan AC). For accuracy, a best-fit algorithm (Final Surface) was used to analyze deviations of the abutment teeth based on 160 IOS-STLs compared to the reference STLs (16 preparations × 2 IOS-systems × 5 scans per tooth). (3) Results: Analysis revealed homogenous findings with high accuracy for intra- and inter-group comparisons for both IOS systems, with mean values of 80% quantiles from 20 ± 2 μm to 50 ± 5 μm. Supragingival finishing lines demonstrated significantly higher accuracy than epigingival margins when comparing each preparation (p < 0.05), whereas tangential preparations exhibited similar results independent of the gingival location. Morphology of anterior versus posterior teeth showed slightly better results in favor of molars in combination with shoulder preparations only. (4) Conclusion: The clinical challenge for the treatment with full crowns following digital impressions is the location of the prospective restoration margin related to the distance to the gingiva. However, the overall accuracy for all abutment teeth was very high; thus, the factors tested are unlikely to have a strong clinical impact.
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Affiliation(s)
- Selina A. Bernauer
- Department of Reconstructive Dentistry, UZB University Center for Dental Medicine Basel, University of Basel, 4058 Basel, Switzerland; (S.A.B.); (N.U.Z.)
| | | | - Nicola U. Zitzmann
- Department of Reconstructive Dentistry, UZB University Center for Dental Medicine Basel, University of Basel, 4058 Basel, Switzerland; (S.A.B.); (N.U.Z.)
| | - Tim Joda
- Department of Reconstructive Dentistry, UZB University Center for Dental Medicine Basel, University of Basel, 4058 Basel, Switzerland; (S.A.B.); (N.U.Z.)
- Correspondence:
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Ebadian B, Abolhasani M, Heidarpour A, Ziaei M, Jowkar M. Assessment of the relationship between maximum occlusal force and median mandibular flexure in adults: A clinical trial study. J Indian Prosthodont Soc 2020; 20:76-82. [PMID: 32089602 PMCID: PMC7008623 DOI: 10.4103/jips.jips_282_19] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Revised: 09/18/2019] [Accepted: 12/29/2019] [Indexed: 11/22/2022] Open
Abstract
Aim: The narrowing of the mandible during opening and protrusion movements is defined as median mandibular flexure (MMF). MMF is caused by the attachment of mandibular muscles; therefore, it can be assumed that a greater amount of maximum occlusal force (MOF) may cause more flexion and could affect the survival of dental and implant restorations. The purpose of this study was to evaluate any relationship between MOF and MMF in a sample of adults. Settings and Design: In vivo – comparative study. Materials and Methods: In this descriptive, cross-sectional, nondirectional study, a sample of 90 volunteers were recruited (45 men and 45 women). MOF was measured by applying the strain gauge receptor to the first molar region, and MMF was measured by calculating the variation in the intermolar distance by a digital caliper with an accuracy of 0.01 mm using an impression and resulted in the stone cast during the maximum opening and closed-jaw positions. The body mass index (BMI) also was calculated. Statistical Analysis: Data were analyzed using the SPSS software (version 23) inferential and descriptive statistics, linear regression, and Pearson correlation coefficient. P < 0.05 was considered statistically significant. Results: There was no statistically significant relationship between MOF and MMF (P = 0.78), but there was a significant association between MOF and BMI (P < 0.001, r = 0.475) and gender. Conclusion: Although MOF and MMF are both important and effective factors in the success of prosthetic restorations, one cannot be expected by the other and both should be considered in the treatment plan separately.
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Affiliation(s)
- Behnaz Ebadian
- Dental Implants Research Center, Department of Prosthodontics, Dental Research Institute, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Majid Abolhasani
- Dental Implants Research Center, Department of Prosthodontics, Dental Research Institute, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Anahita Heidarpour
- Dental Students' Research Committee, School of Dentistry, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Mohsen Ziaei
- Dental Students' Research Committee, School of Dentistry, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Mohammad Jowkar
- Dental Students' Research Committee, School of Dentistry, Isfahan University of Medical Sciences, Isfahan, Iran
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Mandibular Flexure and Peri-Implant Bone Stress Distribution on an Implant-Supported Fixed Full-Arch Mandibular Prosthesis: 3D Finite Element Analysis. BIOMED RESEARCH INTERNATIONAL 2018; 2018:8241313. [PMID: 29805978 PMCID: PMC5899843 DOI: 10.1155/2018/8241313] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Revised: 02/01/2018] [Accepted: 02/14/2018] [Indexed: 11/17/2022]
Abstract
Purpose The purpose of this study was to evaluate and compare the effect of three mandibular full-arch superstructures on the peri-implant bone stress distribution during mandibular flexure caused by mid-opening (27 mm) and protrusion mandibular movements. Materials and Methods Three-dimensional finite element models were created simulating six osseointegrated implants in the jawbone. One model simulated a 1-piece framework and the other simulated 2-piece and 3-piece frameworks. Muscle forces with definite direction and magnitude were exerted over areas of attachment to simulate multiple force vectors of masticatory muscles during mandibular protrusion and opening. Results During the movement of 27.5 mm jaw opening, the 1-piece and 3-piece superstructures showed the lowest values of bone stress around the mesial implants, gradually increasing towards the distal position. During the protrusion movement, bone stress increased compared to opening for any implant situation and for a divided or undivided framework. The 3-piece framework showed the highest values of peri-implant bone stress, regardless of the implant situation. Conclusions The undivided framework provides the best biomechanical environment during mandibular protrusion and opening. Protrusion movement increases the peri-implant bone stress. The most mesial implants have the lowest biomechanical risk.
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Sivaraman K, Chopra A, Venkatesh SB. Clinical importance of median mandibular flexure in oral rehabilitation: a review. J Oral Rehabil 2015; 43:215-25. [PMID: 26498998 DOI: 10.1111/joor.12361] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/16/2015] [Indexed: 11/29/2022]
Abstract
The mandible has a property to flex inwards around the mandibular symphysis with change in shape and decrease in mandibular arch width during opening and protrusion of the mandible. The mandibular deformation may range from a few micrometres to more than 1 mm. The movement occurs because of the contraction of lateral pterygoid muscles that pulls mandibular condyles medially and causes a sagittal movement of the posterior segments. This movement of mandible can have a profound influence on prognosis and treatment outcome for various restorative, endodontics, fixed, removable and implant-related prosthesis. The review unfolds the causes, importance and clinical implications of median mandibular flexure in oral rehabilitation. This review also highlights the appropriate preventive measures and techniques that should be adopted by clinicians to minimise the effect of flexural movement of the jaw during oral rehabilitation. This would not only help clinicians to achieve a good prosthesis with accurate fit and longevity but also maintain the health of the surrounding periodontal or periimplant gingival tissues and bone.
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Affiliation(s)
- K Sivaraman
- Department of Prosthodontics, Manipal College of Dental Sciences, Manipal University, Manipal, India
| | - A Chopra
- Faculty of Dentistry, Melaka Manipal Medical College, Manipal, India
| | - S B Venkatesh
- Department of Periodontics, A.J. Institute of Dental Sciences, Mangalore, India
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Henderson SE, Tudares MA, Tashman S, Almarza AJ. Decreased Temporomandibular Joint Range of Motion in a Model of Early Osteoarthritis in the Rabbit. J Oral Maxillofac Surg 2015; 73:1695-705. [PMID: 25889371 DOI: 10.1016/j.joms.2015.03.042] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Revised: 03/16/2015] [Accepted: 03/16/2015] [Indexed: 10/23/2022]
Abstract
PURPOSE Analysis of mandibular biomechanics could help with understanding the mechanisms of temporomandibular joint (TMJ) disorders (TMJDs), such as osteoarthritis (TMJ-OA), by investigating the effects of injury or disease on TMJ movement. The objective of the present study was to determine the functional kinematic implications of mild TMJ-OA degeneration caused by altered occlusion from unilateral splints in the rabbit. MATERIALS AND METHODS Altered occlusion of the TMJ was mechanically induced in rabbits by way of a unilateral molar dental splint (n = 3). TMJ motion was assessed using 3-dimensional (3D) skeletal kinematics twice, once before and once after 6 weeks of splint placement with the splints removed, after allowing 3 days of recovery. The relative motion of the condyle to the fossa and the distance between the incisors were tracked. RESULTS An overall decrease in the range of joint movement was observed at the incisors and in the joint space between the condyle and fossa. The incisor movement decreased from 7.0 ± 0.5 mm to 6.2 ± 0.5 mm right to left, from 5.5 ± 2.2 mm to 4.6 ± 0.8 mm anterior to posterior, and from 13.3 ± 1.8 mm to 11.6 ± 1.4 mm superior to inferior (P < .05). The total magnitude of the maximum distance between the points on the condyle and fossa decreased from 3.6 ± 0.8 mm to 3.1 ± 0.6 mm for the working condyle and 2.8 ± 0.4 mm to 2.5 ± 0.4 mm for the balancing condyle (P < .05). The largest decreases were seen in the anteroposterior direction for both condyles. CONCLUSION Determining the changes in condylar movement might lead to a better understanding of the early predictors in the development of TMJ-OA and determining when the symptoms become a chronic, irreversible problem.
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Affiliation(s)
- Sarah E Henderson
- Graduate Student Researcher, Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA
| | - Mauro A Tudares
- Research Technician, Department of Oral Biology, University of Pittsburgh, Pittsburgh, PA
| | - Scott Tashman
- Associate Professor, Department of Orthopaedic Surgery, University of Pittsburgh, Pittsburgh, PA
| | - Alejandro J Almarza
- Associate Professor, Department of Bioengineering; Department of Oral Biology; and McGowan Institute of Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA.
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Naves MM, de Menezes HHM, de Magalhães D, de Araújo CA, Júnior PCS. The Influence of Interproximal Contact on Implant-Supported Fixed Partial Dentures in the Posterior Jaw: A Photoelastic Analysis. J ORAL IMPLANTOL 2015; 41:3-9. [DOI: 10.1563/aaid-joi-d-12-00118] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The aim of this study was to analyze the effect of the separation of prosthetic crowns from fixed partial dentures by means of stress gradient evaluation. Three photoelastic models were created to examine contiguous implants with varying contact between the crowns (contact point [CP], contact surface [CS], splinted [SP]). The SP group presented the best results, followed by the CS group, indicating that the use of splinted prosthetic crowns and crowns with broad surface contacts is viable when considering the stress values.
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Affiliation(s)
- Marina Melo Naves
- Department of Post-Graduation, Dental School, Federal University of Uberlandia and Periodontology and Implantology Department, HD Postgraduate Dental Education Center, Uberlandia, Brazil
| | | | - Denildo de Magalhães
- Periodontology and Implantology Department, Dental School, Federal University of Uberlandia, Uberlandia, Brazil
| | - Cleudmar Amaral de Araújo
- Mechanical Projects Laboratory Henner A. Gomide, Mechanical School, Federal University of Uberlandia, Uberlandia, Brazil
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18
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De Santis R, Gloria A, Russo T, D'Amora U, Varriale A, Veltri M, Balleri P, Mollica F, Riccitiello F, Ambrosio L. Reverse engineering of mandible and prosthetic framework: Effect of titanium implants in conjunction with titanium milled full arch bridge prostheses on the biomechanics of the mandible. J Biomech 2014; 47:3825-9. [PMID: 25468297 DOI: 10.1016/j.jbiomech.2014.10.020] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2013] [Revised: 04/08/2014] [Accepted: 10/16/2014] [Indexed: 11/27/2022]
Abstract
This study aimed at investigating the effects of titanium implants and different configurations of full-arch prostheses on the biomechanics of edentulous mandibles. Reverse engineered, composite, anisotropic, edentulous mandibles made of a poly(methylmethacrylate) core and a glass fibre reinforced outer shell were rapid prototyped and instrumented with strain gauges. Brånemark implants RP platforms in conjunction with titanium Procera one-piece or two-piece bridges were used to simulate oral rehabilitations. A lateral load through the gonion regions was used to test the biomechanical effects of the rehabilitations. In addition, strains due to misfit of the one-piece titanium bridge were compared to those produced by one-piece cast gold bridges. Milled titanium bridges had a better fit than cast gold bridges. The stress distribution in mandibular bone rehabilitated with a one-piece bridge was more perturbed than that observed with a two-piece bridge. In particular the former induced a stress concentration and stress shielding in the molar and symphysis regions, while for the latter design these stresses were strongly reduced. In conclusion, prosthetic frameworks changed the biomechanics of the mandible as a result of both their design and manufacturing technology.
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Affiliation(s)
- Roberto De Santis
- Institute of Polymers, Composites and Biomaterials, National Research Council of Italy, V.le J.F. Kennedy 54, Mostra d׳Oltremare (PAD. 20), 80125 Naples, Italy
| | - Antonio Gloria
- Institute of Polymers, Composites and Biomaterials, National Research Council of Italy, V.le J.F. Kennedy 54, Mostra d׳Oltremare (PAD. 20), 80125 Naples, Italy.
| | - Teresa Russo
- Institute of Polymers, Composites and Biomaterials, National Research Council of Italy, V.le J.F. Kennedy 54, Mostra d׳Oltremare (PAD. 20), 80125 Naples, Italy
| | - Ugo D'Amora
- Institute of Polymers, Composites and Biomaterials, National Research Council of Italy, V.le J.F. Kennedy 54, Mostra d׳Oltremare (PAD. 20), 80125 Naples, Italy
| | - Angelo Varriale
- Department of Oral Surgery and Implantology, University of Siena, Via Banchi di Sotto 55, 53100 Siena, Italy
| | - Mario Veltri
- Department of Oral Surgery and Implantology, University of Siena, Via Banchi di Sotto 55, 53100 Siena, Italy
| | - Piero Balleri
- Department of Oral Surgery and Implantology, University of Siena, Via Banchi di Sotto 55, 53100 Siena, Italy
| | - Francesco Mollica
- Department of Materials Engineering, University of Ferrara, Via Saragat 1, 44100 Ferrara, Italy
| | - Francesco Riccitiello
- Department of Oral and Maxillofacial Sciences, University of Naples "Federico II", Via Pansini 5, 80131 Naples, Italy
| | - Luigi Ambrosio
- Institute of Polymers, Composites and Biomaterials, National Research Council of Italy, V.le J.F. Kennedy 54, Mostra d׳Oltremare (PAD. 20), 80125 Naples, Italy
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Choi AH, Conway RC, Taraschi V, Ben-Nissan B. Biomechanics and functional distortion of the human mandible. ACTA ACUST UNITED AC 2014; 6:241-51. [DOI: 10.1111/jicd.12112] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2014] [Accepted: 04/04/2014] [Indexed: 11/30/2022]
Affiliation(s)
- Andy H. Choi
- School of Chemistry and Forensic Science; Faculty of Science; University of Technology; Sydney NSW Australia
| | - Richard C. Conway
- School of Chemistry and Forensic Science; Faculty of Science; University of Technology; Sydney NSW Australia
- Department of Oral and Maxillofacial Surgery; Westmead Hospital; Sydney NSW Australia
| | - Valerio Taraschi
- School of Chemistry and Forensic Science; Faculty of Science; University of Technology; Sydney NSW Australia
| | - Besim Ben-Nissan
- School of Chemistry and Forensic Science; Faculty of Science; University of Technology; Sydney NSW Australia
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Prasad M, Hussain MZ, Shetty SK, Kumar TA, Khaur M, George SA, Dalwai S. Median mandibular flexure at different mouth opening and its relation to different facial types: A prospective clinical study. J Nat Sci Biol Med 2013; 4:426-30. [PMID: 24082745 PMCID: PMC3783793 DOI: 10.4103/0976-9668.117028] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Objective: To measure the arch width and Median mandibular flexure (MMF) values at relative rest and maximum jaw opening in young adults with Dolichofacial, Mesofacial, and Brachyfacial types and tested whether the variation in the facial pattern is related to the MMF values in South Indian population. Materials and Methods: This Prospective clinical study consisted of sample of 60 young adults. The subjects were grouped into 3 groups: Group 1: Brachyfacial, Group 2: Mesofacial and types, Group 3: Dolichofacial. Impressions were taken for all the 60 subjects and the casts were scanned and digitized. The intermolar width was measured for Dolichofacial, Mesofacial, and Brachyfacial subjects at relative rest (R) and maximum opening (O). Results: The statistical analysis of the observations included Descriptive and Inferential statistics. The statistical analysis was executed by means of Sigma graph pad prism software, USA Version-4. Kruskal wallis (ANOVA) followed by Dunns post hoc test was performed. Mann Whitney U-test was performed to assess the difference in MMF values between Males and Females of the three groups. The Mean (SD) Mandibular flexure in individuals with Brachyfacial type was 1.12 (0.09), Mesofacial type was 0.69 (0.21), and Dolichofacial type was 0.39 (0.08). Conclusions: The Mean intermolar width was maximum in Brachyfacial type and minimum in Dolichofacial type. MMF was maximum at the maximum mouth opening position and was maximum in individuals with Brachyfacial type.
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Affiliation(s)
- Mandava Prasad
- Department of Orthodontics and Dentofacial Orthopedics, Narayana Dental College and Hospital, Chinthareddypalem, Nellore, Andhra Pradesh, India
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Chou HY, Satpute D, Müftü A, Mukundan S, Müftü S. Influence of mastication and edentulism on mandibular bone density. Comput Methods Biomech Biomed Engin 2013; 18:269-81. [PMID: 23682930 DOI: 10.1080/10255842.2013.792916] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
The aim of this study was to demonstrate that external loading due to daily activities, including mastication, speech and involuntary open-close cycles of the jaw contributes to the internal architecture of the mandible. A bone remodelling algorithm that regulates the bone density as a function of stress and loading cycles is incorporated into finite element analysis. A three-dimensional computational model is constructed on the basis of computerised tomography (CT) images of a human mandible. Masticatory muscle activation involved during clenching is modelled by static analysis using linear optimisation. Other loading conditions are approximated by imposing mandibular flexure. The simulations predict that mandibular bone density distribution results in a tubular structure similar to what is observed in the CT images. Such bone architecture is known to provide the bone optimum strength to resist bending and torsion during mastication while reducing the bone mass. The remodelling algorithm is used to simulate the influence of edentulism on mandibular bone loss. It is shown that depending on the location and number of missing teeth, up to one-third of the mandibular bone mass can be lost due to lack of adequate mechanical stimulation.
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Affiliation(s)
- Hsuan-Yu Chou
- a Department of Mechanical Engineering , Northeastern University , Boston , MA 02115 , USA
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22
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Sarrafpour B, Swain M, Li Q, Zoellner H. Tooth eruption results from bone remodelling driven by bite forces sensed by soft tissue dental follicles: a finite element analysis. PLoS One 2013; 8:e58803. [PMID: 23554928 PMCID: PMC3598949 DOI: 10.1371/journal.pone.0058803] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2012] [Accepted: 02/06/2013] [Indexed: 11/18/2022] Open
Abstract
Intermittent tongue, lip and cheek forces influence precise tooth position, so we here examine the possibility that tissue remodelling driven by functional bite-force-induced jaw-strain accounts for tooth eruption. Notably, although a separate true 'eruptive force' is widely assumed, there is little direct evidence for such a force. We constructed a three dimensional finite element model from axial computerized tomography of an 8 year old child mandible containing 12 erupted and 8 unerupted teeth. Tissues modelled included: cortical bone, cancellous bone, soft tissue dental follicle, periodontal ligament, enamel, dentine, pulp and articular cartilage. Strain and hydrostatic stress during incisive and unilateral molar bite force were modelled, with force applied via medial and lateral pterygoid, temporalis, masseter and digastric muscles. Strain was maximal in the soft tissue follicle as opposed to surrounding bone, consistent with follicle as an effective mechanosensor. Initial numerical analysis of dental follicle soft tissue overlying crowns and beneath the roots of unerupted teeth was of volume and hydrostatic stress. To numerically evaluate biological significance of differing hydrostatic stress levels normalized for variable finite element volume, 'biological response units' in Nmm were defined and calculated by multiplication of hydrostatic stress and volume for each finite element. Graphical representations revealed similar overall responses for individual teeth regardless if incisive or right molar bite force was studied. There was general compression in the soft tissues over crowns of most unerupted teeth, and general tension in the soft tissues beneath roots. Not conforming to this pattern were the unerupted second molars, which do not erupt at this developmental stage. Data support a new hypothesis for tooth eruption, in which the follicular soft tissues detect bite-force-induced bone-strain, and direct bone remodelling at the inner surface of the surrounding bony crypt, with the effect of enabling tooth eruption into the mouth.
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Affiliation(s)
- Babak Sarrafpour
- The Cellular and Molecular Pathology Research Unit, Department of Oral Pathology and Oral Medicine, Faculty of Dentistry, The University of Sydney, Westmead Hospital, Westmead, New South Wales, Australia.
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Shinkai RSA, Canabarro SDA, Schmidt CB, Sartori EA. Reliability of a digital image method for measuring medial mandibular flexure in dentate subjects. J Appl Oral Sci 2012; 12:358-62. [PMID: 20976412 DOI: 10.1590/s1678-77572004000400020] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2004] [Accepted: 10/19/2004] [Indexed: 11/22/2022] Open
Abstract
UNLABELLED Medial mandibular flexure (MMF) is the functional approximation of hemi-mandibles in jaw opening and protrusion, which may affect conventional or implant-supported arch prostheses. OBJECTIVE This study evaluated the intra- and inter-rater reliability of a digital image method for linear measurement of MMF in dentate subjects. MATERIAL AND METHODS Mandibular occlusal impressions in vinyl polysiloxane during rest and maximum opening were obtained from seven adult volunteers. Each impression and the Mitutoyo digital calipers with a 10mm opening were scanned at a 200% magnification. The images were processed using Adobe Photoshop software to get reference points on contralateral first molars. Linear intermolar measurements were taken using the Image Tool software (UTHSCSA), which was calibrated with the standard opening of the digital calipers. Intermolar distance was measured in triplicate for each image by two independent examiners. MMF was calculated by subtracting the intermolar distance in maximum opening (or protrusion) from the distance in rest position. Data were analyzed by intraclass correlation (ICC) tests for estimating intra- and inter-rater reliability. RESULTS MMF values ranged from -0.21 to 0.44mm. Intra-rater ICCs were 0.982 and 0.993, and inter-rater ICC was 0.696. CONCLUSION The present results show excellent intra-rater and good inter-rater reliability of this digital image method for measuring MMF in dentate subjects.
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Radke JC, Kull RS. Distribution of temporomandibular joint vibration transfer to the opposite side. Cranio 2012; 30:194-200. [PMID: 22916672 DOI: 10.1179/crn.2012.030] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
A vibration produced when a displaced temporomandibular disc reduces during opening can transfer some of its energy from the ipsilateral joint to the contralateral joint. The objective of this study was to measure what percentage of the ipsilateral vibration is transferred to the contralateral joint. The study included the temporomandibular joint (TMJ) vibrations of 144 (informed consent) subjects, (113 F, 31 M), with reducing displaced discs (DDR). Vibrations from 165 joints were recorded bilaterally with BioJVA (BioResearch Associates, Inc. Milwaukee, WI). In each case, any contralateral vibration was analyzed to verify that it was caused by the ipsilateral joint. The contralateral amplitude was divided by the ipsilateral amplitude and multiplied by 100 to produce a percentage of transfer. The percentage values (0-100%) were used to create a Relative Frequency Histogram with 20 classes (1-5%, 6-10%, 11-15%, etc.). The Relative Frequency Histogram graph revealed a three-mounded distribution of the percentage of transfer. One mound fell between 5 and 34 percent, one between 35 and 69 percent and the third between 70 and 98 percent. The appearance of a three-mounded distribution suggests that there may be three different failure modes leading to TMJ intemal derangements. Alternatively, it may be that failure of the disc's stabilizing ligaments leads to three different internal derangement conditions that are in some way distinct. The evidence of apparent tri-modality in this vibration data distribution suggests that there may be three different failure modes of disc displacement with reduction (e.g., anterior, anteromedial, and medio-lateral disc displacement). If so, identifying them could allow for a more detailed description of DDR. Therefore, further investigation of this 'tri-modal' distribution should be undertaken.
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Affiliation(s)
- John C Radke
- BioResearch Associates, Inc, Milwaukee, Wisconsin, USA.
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Sarrafpour B, Rungsiyakull C, Swain M, Li Q, Zoellner H. Finite element analysis suggests functional bone strain accounts for continuous post-eruptive emergence of teeth. Arch Oral Biol 2012; 57:1070-8. [DOI: 10.1016/j.archoralbio.2012.05.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2011] [Revised: 04/02/2012] [Accepted: 05/07/2012] [Indexed: 11/30/2022]
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Law C, Bennani V, Lyons K, Swain M. Mandibular flexure and its significance on implant fixed prostheses: a review. J Prosthodont 2011; 21:219-24. [PMID: 22044758 DOI: 10.1111/j.1532-849x.2011.00798.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
PURPOSE The aims of this review are to determine the effect of mandibular flexure on the "implant-framework system," and analyze the existing literature on the topic. MATERIALS AND METHODS A MEDLINE and PubMed search was conducted to identify any articles in English related to the topic published up to May 2010 using the search words "mandible,""dental implants,""dental impression technique,""jaw movement,""dental stress analysis," and "mechanical stress." RESULTS The search identified 40 and 36 articles from MEDLINE and PubMed, respectively. Twenty articles met the inclusion criteria. CONCLUSIONS Mandibular flexure is a multifactorial phenomenon, and the effect of the implant-framework system in this is unclear. Studies have focused mainly on the fully edentulous mandible. These have found that mandibular flexure should be taken into consideration when designing a prosthesis and have suggested that dividing the prosthesis at the symphysis region, or into multiple implant fixed dental prostheses, may minimize the effect of mandibular flexure on the implant prosthesis. At this time, no studies have investigated the effect of mandibular flexure on long-span, unilateral, implant fixed prostheses. The clinical significance of mandibular flexure on the success of dental implant treatment is at this time unclear, and further research is needed.
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Affiliation(s)
- Constance Law
- Department of Oral Rehabilitation, University of Otago, Dunedin, New Zealand
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Zaugg B, Hämmerle CHF, Palla S, Gallo LM. Implant-supported mandibular splinting affects temporomandibular joint biomechanics. Clin Oral Implants Res 2011; 23:897-901. [DOI: 10.1111/j.1600-0501.2011.02241.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Custodio W, Gomes SGF, Faot F, Garcia RCMR, Del Bel Cury AA. Occlusal force, electromyographic activity of masticatory muscles and mandibular flexure of subjects with different facial types. J Appl Oral Sci 2011; 19:343-9. [PMID: 21655772 PMCID: PMC4223785 DOI: 10.1590/s1678-77572011005000008] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2009] [Accepted: 03/06/2010] [Indexed: 11/22/2022] Open
Abstract
Objective The aim of this study was to evaluate whether vertical facial patterns influence
maximal occlusal force (MOF), masticatory muscle electromyographic (EMG) activity,
and medial mandibular flexure (MMF). Material and Methods Seventy-eight dentate subjects were divided into 3 groups by Ricketts's analysis:
brachyfacial, mesofacial and dolychofacial. Maximum occlusal force in the molar
region was bilaterally measured with a force transducer. The electromyographic
activities of the masseter and anterior temporal muscles were recorded during
maximal voluntary clenching. Medial mandibular flexure was calculated by
subtracting the intermolar distance of maximum opening or protrusion from the
distance in the rest position. The data were analyzed using ANOVA followed by
Tukey's HSD test. The significance level was set at 5%. Results Data on maximum occlusal force showed that shorter faces had higher occlusal
forces (P<0.0001). Brachyfacial subjects presented higher levels of masseter
electromyographic activity and medial mandibular flexure, followed by the
mesofacial and dolychofacial groups. Additionally, dolychofacial subjects showed
significantly lower electromyographic temporalis activities (P<0.05). Conclusion Within the limitations of the study, it may be concluded that maximum occlusal
force, masticatory muscle activity and medial mandibular flexure were influenced
by the vertical facial pattern.
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Affiliation(s)
- William Custodio
- Department of Prosthodontics and Periodontology, Piracicaba Dental School, State University of Campinas, Piracicaba, SP, Brazil
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Gonshor A, Saroff SA, Anderegg CR, Joachim FPC, Charon JA, Prasad H, Katta S. Histologic and Clinical Evaluation of a Bioactive Calcium Phosphosilicate Bone Graft Material in Postextraction Alveolar Sockets. ACTA ACUST UNITED AC 2011. [DOI: 10.5005/jp-journals-10012-1040] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Mapelli A, Galante D, Lovecchio N, Sforza C, Ferrario VF. Translation and rotation movements of the mandible during mouth opening and closing. Clin Anat 2009; 22:311-8. [DOI: 10.1002/ca.20756] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Shinkai RS, Lazzari FL, Canabarro SA, Gomes M, Grossi ML, Hirakata LM, Mota EG. Maximum occlusal force and medial mandibular flexure in relation to vertical facial pattern: a cross-sectional study. Head Face Med 2007; 3:18. [PMID: 17407566 PMCID: PMC1851008 DOI: 10.1186/1746-160x-3-18] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2006] [Accepted: 04/02/2007] [Indexed: 11/19/2022] Open
Abstract
Background Vertical facial pattern may be related to the direction of pull of the masticatory muscles, yet its effect on occlusal force and elastic deformation of the mandible still is unclear. This study tested whether the variation in vertical facial pattern is related to the variation in maximum occlusal force (MOF) and medial mandibular flexure (MMF) in 51 fully-dentate adults. Methods Data from cephalometric analysis according to the method of Ricketts were used to divide the subjects into three groups: Dolichofacial (n = 6), Mesofacial (n = 10) and Brachyfacial (n = 35). Bilateral MOF was measured using a cross-arch force transducer placed in the first molar region. For MMF, impressions of the mandibular occlusal surface were made in rest (R) and in maximum opening (O) positions. The impressions were scanned, and reference points were selected on the occlusal surface of the contralateral first molars. MMF was calculated by subtracting the intermolar distance in O from the intermolar distance in R. Data were analysed by ANCOVA (fixed factors: facial pattern, sex; covariate: body mass index (BMI); alpha = 0.05). Results No significant difference of MOF or MMF was found among the three facial patterns (P = 0.62 and P = 0.72, respectively). BMI was not a significant covariate for MOF or MMF (P > 0.05). Sex was a significant factor only for MOF (P = 0.007); males had higher MOF values than females. Conclusion These results suggest that MOF and MMF did not vary as a function of vertical facial pattern in this Brazilian sample.
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Affiliation(s)
- Rosemary S Shinkai
- Department of Prosthodontics, Pontifical Catholic University of Rio Grande do Sul, Porto Alegre, RS, Brazil
- Graduate Program in Dentistry, Pontifical Catholic University of Rio Grande do Sul, Porto Alegre, RS, Brazil
| | | | - Simone A Canabarro
- Graduate Program in Dentistry, Pontifical Catholic University of Rio Grande do Sul, Porto Alegre, RS, Brazil
- Private Practice, Caxias do Sul, RS, Brazil
| | - Márcia Gomes
- Graduate Program in Dentistry, Federal University of Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Márcio L Grossi
- Graduate Program in Dentistry, Pontifical Catholic University of Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Luciana M Hirakata
- Department of Prosthodontics, Pontifical Catholic University of Rio Grande do Sul, Porto Alegre, RS, Brazil
- Graduate Program in Dentistry, Pontifical Catholic University of Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Eduardo G Mota
- Department of Prosthodontics, Pontifical Catholic University of Rio Grande do Sul, Porto Alegre, RS, Brazil
- Graduate Program in Dentistry, Pontifical Catholic University of Rio Grande do Sul, Porto Alegre, RS, Brazil
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De Santis R, Mollica F, Zarone F, Ambrosio L, Nicolais L. Biomechanical effects of titanium implants with full arch bridge rehabilitation on a synthetic model of the human jaw. Acta Biomater 2007; 3:121-6. [PMID: 16997642 DOI: 10.1016/j.actbio.2006.07.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2005] [Revised: 06/06/2006] [Accepted: 07/06/2006] [Indexed: 11/22/2022]
Abstract
A composite model of the mandible, constituted by an inner polymeric core and a glass fibre reinforced outer shell, has been developed and equipped with six ITI titanium implants and a full gold alloy arch bridge prosthesis. The effects of this oral rehabilitation on the biomechanics of the mandible are investigated through a simulation of the lateral component of the pterygoid muscles. These muscles are involved as the mouth is opened and closed, hence their activity is very frequent. An increase of the mandible stiffness due to the prosthesis is observed; moreover, the coupling of the relatively stiff rehabilitation devices with the natural tissue analogue leads to stress-shielding and stress-concentration in the incisal and molar regions, respectively. Although the amplitude of the force generated by pterygoid muscles is quite small, high strains over the incisal region are measured. A stress-shielding effect, of about 20%, is observed at the symphysis as the full arch bridge prosthesis is fixed on the implants. Therefore, the presence of the prosthesis leads to significant modification of the stress field experienced by the mandible, and this may be relevant in relation to the biomechanics of mandibular bone remodelling.
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Affiliation(s)
- Roberto De Santis
- Institute for Composite and Biomedical Materials, National Research Council, Piazzale Tecchio 80, 80125 Napoli, Italy
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Herring SW. Masticatory muscles and the skull: a comparative perspective. Arch Oral Biol 2006; 52:296-9. [PMID: 17084804 PMCID: PMC1853336 DOI: 10.1016/j.archoralbio.2006.09.010] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2006] [Revised: 09/13/2006] [Accepted: 09/17/2006] [Indexed: 11/23/2022]
Abstract
Masticatory muscles are anatomically and functionally complex in all mammals, but relative sizes, orientation of action lines, and fascial subdivisions vary greatly among different species in association with their particular patterns of occlusion and jaw movement. The most common contraction pattern for moving the jaw laterally involves a force couple of protrusor muscles on one side and retrusors on the other. Such asymmetrical muscle usage sets up torques on the skull and combines with occlusal loads to produce bony deformations not only in the tooth-bearing jaw bones, but also in more distant elements such as the braincase. Maintenance of bone in the jaw joint, and probably elsewhere in the skull, is dependent on these loads.
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Affiliation(s)
- Susan W Herring
- Department of Orthodontics, University of Washington, Box 357446, Seattle, WA 98195-7446, USA.
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Yamashita J, Wang Q, Dechow PC. Biomechanical effects of fixed partial denture therapy on strain patterns of the mandible. J Prosthet Dent 2006; 95:55-62. [PMID: 16399276 DOI: 10.1016/j.prosdent.2005.11.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
STATEMENT OF PROBLEM The mandibular posterior 3-unit fixed partial denture (FPD) is a conventional prosthodontic therapy and presumably has an effect on the direction and magnitude of occlusal forces and, thus, on the biomechanical environment of the mandible, which may in turn affect bone structure. However, the impact of FPD therapy on mandibular biomechanics is unknown. PURPOSE The purpose of this study was to test the hypothesis that 3-unit FPD therapy alters strain patterns in the mandible during loading. MATERIAL AND METHODS Four human cadaver mandibles missing first molars were bilaterally fixed and artificially loaded on each tooth individually. Surface cortical bone strains were measured with multiple strain gauges during loading of up to 250 N. Next, 3-unit FPDs with a chamfer finish line were fabricated using Type IV gold alloy. Strain measurements were conducted in the same manner to assess differences in strain patterns before and after therapy. Paired-sample tests for metric and angular data were used to assess difference in strain pattern before and after therapies (alpha=.05). RESULTS When loading was applied on the teeth not involved in FPD therapy, no differences were found before and after FPD placement. When the posterior retainers were loaded, the strain distribution differed (P=.01); on the buccal cortices, strain levels increased posteriorly but decreased significantly anteriorly. However, these differences were less than 100 muepsilon, and the overall deformation pattern of the mandible after the FPD therapy was similar to that before FPD therapy. Strain distributions when the pontic was loaded were similar to those when the posterior retainer was loaded. CONCLUSION Three-unit FPD therapy did not alter the overall deformation pattern of the mandible during loading.
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Affiliation(s)
- Junro Yamashita
- Department of Biologic Materials and Sciences, Division of Prosthodontics, School of Dentistry, University of Michigan, Ann Arbor, 48109, USA.
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De Santis R, Mollica F, Esposito R, Ambrosio L, Nicolais L. An experimental and theoretical composite model of the human mandible. JOURNAL OF MATERIALS SCIENCE. MATERIALS IN MEDICINE 2005; 16:1191-7. [PMID: 16362221 DOI: 10.1007/s10856-005-4728-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2005] [Accepted: 08/19/2005] [Indexed: 05/05/2023]
Abstract
The purpose is to design and manufacture a composite mandible replicate suitable for testing the influence of prosthetic materials on the stress distribution of bone. Composite mandibles made of a poly(methylmethacrylate) core and a glass reinforced outer shell are manufactured and characterised through mechanical tests assisted by the finite element analysis. The mandible replicate has been conveniently equipped with strain gauges, moreover a video extensometer has also been used in order to measure the arch width change during loading. A close agreement is found between the experimental data and the theoretical predictions. By laterally loading the mandibles the maximum values of stress and strain take place in the premolar-incisal region. By varying technological parameters such as the fiber volume fraction and orientation, it is easy to replicate the behaviour of mandibles having different stiffnesses. The results obtained by laterally loading the composite mandibles through the condyles or through the gonion regions are consistent with literature data relative to the arch width decrease of natural jaws during opening and closing. This novel synthetic system coupled with the Finite Element model constitutes an experimental-theoretical model suitable to investigate the biomechanical effects of oral rehabilitations on mandibular bone.
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Affiliation(s)
- R De Santis
- Institute of Composite and Biomedical Materials-National Research Council, Piazzale Tecchio 80, Napoli, 80125, Italy.
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Ferrario VF, Sforza C, Lovecchio N, Mian F. Quantification of translational and gliding components in human temporomandibular joint during mouth opening. Arch Oral Biol 2005; 50:507-15. [PMID: 15777532 DOI: 10.1016/j.archoralbio.2004.10.002] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2004] [Accepted: 10/06/2004] [Indexed: 12/01/2022]
Abstract
OBJECTIVE In humans, the opening movement of the mouth requires a complex combination of rotation in the lower temporomandibular joint compartment and of translation in the upper compartment. The aim of the current study was to quantitatively assess the percentage contribution of rotation and translation movements of the mandible at maximum mouth opening in normal, healthy individuals. DESIGN Free, habitual movements of mouth opening were recorded in 12 men and 15 women aged 19-30 years using an optoelectronic three-dimensional motion analyser. All subjects had a sound, complete, permanent dentitions with Angle Class I jaw relationships, without cast restorations or cuspal coverage, TMJ or craniocervical disorders. For each subject, the mandibular movements at the interincisor point (occlusal plane) were reconstructed, and, using suitable mathematical algorithms, divided into their rotation and gliding components. The relative contribution of the two components to the total movement was calculated for each frame of motion. In particular, the situation at maximum opening was assessed. RESULTS At maximum mouth opening, on average, men had significantly larger displacement of the mandibular interincisor point (56 mm versus 46 mm) and angle of rotation (34 degrees versus 32 degrees), than women. The percentage of mandibular movement explained by rotation at maximum mouth opening (77%) was not influenced by sex. The degree of rotation was significantly related to the displacement of the interincisor point: in women r2 = 87%, in men, r2 = 45%. CONCLUSIONS Overall, in normal subjects with a healthy stomatognathic apparatus, mouth opening was more determined by mandibular rotation than by translation.
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Affiliation(s)
- Virgilio F Ferrario
- Laboratorio di Anatomia Funzionale dell'Apparato Stomatognatico (LAFAS), Functional Anatomy Research Center (FARC), Dipartimento di Morfologia Umana, Facoltà di Medicina e Chirurgia, Università degli Studi di Milano, Milano, MI, Italy.
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Entrup W. Universal/Digestive jaw. MANUELLE MEDIZIN 2004. [DOI: 10.1007/s00337-004-0326-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Miyamoto Y, Fujisawa K, Takechi M, Momota Y, Yuasa T, Tatehara S, Nagayama M, Yamauchi E. Effect of the additional installation of implants in the posterior region on the prognosis of treatment in the edentulous mandibular jaw. Clin Oral Implants Res 2003; 14:727-33. [PMID: 15015949 DOI: 10.1046/j.0905-7161.2003.00958.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The aim of this study was to elucidate the effect of the additional installation of implants in the posterior region on the prognosis of treatment in the edentulous mandibular jaw. Fifteen patients who had received implants (Brånemark system, Nobel Biocare, Gotebörg, Sweden) in the edentulous mandible and completed a 1-year follow-up after the fitting of implant-anchored fixed prostheses were selected. In seven patients (Group A), four or five implants were installed between the mental foramina, and in eight patients (Group P), one or two implants, one on each side, were installed in the posterior regions in addition to the implants between the foramina. All implants of both groups achieved osseointegration. In Group A, there was no implant loss after loading. Six implants were lost in five patients of Group P within 1 year after loading. All of them were located in the posterior region. To elucidate whether or not the failure rate of the implants in the posterior region of Group P after loading was especially high, the failures were also compared with 89 implants, which were installed in the posterior region of the mandibles to support implant-anchored fixed partial prosthesis, during the same period (Group C). The cumulative survival rate of the implants of Group P was 60%, while that of the implants of Group C was 100% (P<0.001). When the survival rates of posterior implants with the same length of the two groups were compared, there were significant differences for the 7- and 10-mm-length implants only. These data demonstrate that the posterior implants in Group P are at greater risk. Deformation of the mandible due to jaw movement was thought to be the most likely cause of the implant loss. Therefore, when such modified treatment is chosen, it should be performed with meticulous attention.
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Affiliation(s)
- Youji Miyamoto
- First Department of Oral and Maxillofacial Surgery, School of Dentistry, University of Tokushima, Tokushima, Japan.
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