J Prosthet Dent. Stability is the resistance to lateral movement of an RPD and is provided by minor connectors, proximal plates, bracing clasp arms, and resin or metal denture bases. Incisal rests are unesthetic, increase length of fulcrum, and interfere with occlusion in protrusive movements. 2012;39:791–8. of removable partial denture (RPD) design: a clasp assembly consisting of a rest, a proximal plate, and an I-bar retainer. a bridge) or removable. Class IV is a tooth-supported RPD. Partial denture: A prosthesis that replaces one or more, but not all of the natural teeth and supporting structures. Int J Prosthodont. Channel rests are also commonly used on a distal abutment molar that has a mesial inclination for a rotation path of insertion RPD. In the 1960s, Professor F. J. Kratochvil recognized the importance of biomechanics in removable partial denture (RPD) design and used these principles to develop a new design philosophy. RPD Biomechanics Two types of RPD’s Tooth borne Occlusal forces are transmitted to the teeth used as RPD abutments Extension base Occlusal forces are shared between the abutment teeth and the edentulous denture bearing surfaces. Forces Acting On Partial Denture. They tend to direct forces down the long axis of a posterior abutment tooth. J Oral Rehabil. Kono K, Kurihara D, Suzuki Y, Ohkubo C. Pressure distribution of implant-supported removable partial dentures with stress-breaking attachments. J Prosthet Dent. When adequate lingual depth of at least 10 mm is present or an RPI or RPA clasp design is utilized, then a lingual bar is used as major connector. 2005;93:267–73. Technology with digital workflow processes will change removable prosthodontics as we currently know it, although human biology and biomechanics will not change. Effect of two clasping assemblies on arch integrity as modified by base adaptation. Kennedy E. Partial Denture Construction. © Springer International Publishing Switzerland 2016, Department of Prosthodontics, Faculty of Dentistry, https://doi.org/10.1007/978-3-319-20556-4_4. 2008;3:133–9. Properly designed indirect retention reduces ANP torsional leverage on the principal abutments. Functional mandibular movement is defined as all the normal, proper, or characteristic of three-dimensional movements of the mandible during speech, mastication, swallowing, and other associated movements. We must look at these removable prosthetic cases objectively to understand how future RPDs can be improved for the partially edentulous patient. Fig. Resistance t… J Prosthet Dent. The Class IV is largely tooth supported and commonly utilizes a rotational path of insertion RPD design. Mandibular implant-supported removable partial denture with distal extension: a systematic review. An indirect retainer acts as a third point of reference for visual indication to determine the need to reline the RPD when it fails to fully seat as the extension base is displaced toward the edentulous ridge (Figure 17). Many concepts and philosophies in removable partial denture design are not possible to cover in this short article. 2013;24:20–7. Connelly M and Pagan W. Removable Partial Denture Theory and Design. A randomized clinical trial of two basic removable partial denture designs. Lee HE, Wu JH, Wang CH, Lan TH, Du JE. For a Class I Maxillary RPD, the most common major connector would be a posterior palatal coverage/plate (Figure 15). Occlusal rests are spoon shaped and are deepest at the center of the preparation while having a horizontal dimension of one-third the width of the occlusal table at the marginal ridge. (18,23) One of the principal functions of a RPD is the preservation of the remaining dentition. If future anterior tooth loss is expected, or high lingual frenum attachment or inadequate lingual depth exists, then a lingual plate would be indicated. Implants and bridges are commonly used in these partially edentulous areas. 2005;94:10–92. Within this broad definition of partial dentures, one could include interim or provisional prostheses along with definitive removable prosthetics. A look at bio-mechanical principles involved in removable partial denture design and their role in primary and secondary retention. Class IV is a single bilateral edentulous area located anterior to the remaining natural teeth. To understand the variables in RPD design or form, we must consider function first. Explain why a proper clinical and technical assessment of the oral condition is essential to a successful removable partial denture. Distal abutments that have a high height of contour that cannot be modified are a good choice for the wrought wire clasp design. This service is more advanced with JavaScript available, Removable Partial Dentures J Prosthet Dent. These prepared surfaces include various types of rests that provide vertical support for the RPD such as: occlusal, cingulum, ball, channel, and incisal rests. This type of palatal coverage is important to provide support and stability to the RPD. 1989;62:313–9. Study 62 RPD Biomechanics and Design flashcards from Ashley Z. on StudyBlue. Authors: Ting-Ling Chang Daniela Orellana John Beumer III Description: In the 1960s, Professor F. J. Kratochvil recognized the importance of biomechanics in removable partial denture (RPD) design and used these principles to develop a new design philosophy. Most minor connectors extend from the major connector to a prepared surface of the tooth. Implant supported dentures are becoming popular for prosthetic restorations in partially edentulous patients. de Freitas RF, de Carvalho Dias K, da Fonte Porto Carreiro A, Barbosa GA, Ferreira MA. Class II partial dentures are tooth and tissue supported. These stress forces during function include dislodging, horizontal, torsional, and vertical displacement forces. Registration on CDEWorld is free. Major connectors on the maxillary arch should make every attempt to be 4-6 mm from the free gingival margins of remaining teeth. Rotational movement of the denture in the sagittal plane. The saggital plane B. 3. 10 ). Not affiliated Sahin V, Akaltan F, Parnas L. Effects of the type and rigidity of the retainer and the number of abutting teeth on stress distribution of telescopic-retained removable partial dentures. In the 1960s, Professor F. J. Kratochvil recognized the importance of biomechanics in removable partial denture (RPD) design and used these principles to develop a new design philosophy. His initial article in ˜ e Journal of 1988;60:693–6. partial denture. RPD Biomechanics and Design - Prosthodontics 6477 with Hodd at University Of Minnesota School Of Dentistry - … Hanover Park: Quintessence Publishing; 2008. ... -denture base in long span distal extension-artificial tooth replacement. Stereophotogrammetric analysis of abutment tooth movement in distal-extension removable partial dentures with intracoronal attachments and clasps. Study 16 Lec 5 RPD Biomechanics flashcards from on StudyBlue. 2. J Oral Rehabil. Stewart’s clinical removable partial prosthodontics. A provisional or interim removable partial denture is a dental prosthesis used for a short time for reasons of esthetics, mastication, occlusal support, or for conditioning the patient to accept an artificial substitute for missing natural teeth until a more definite prosthetic dental treatment can be provided. 1993;70:245–50. Thus, incisal rests are highly undesirable if anterior esthetics are high on the expectation list. Sato M, Suzuki Y, Kurihara D, Shimpo H, Ohkubo C. Effect of implant support on mandibular distal extension removable partial dentures: relationship between denture supporting area and stress distribution. Aust Dent J. 1992;19:585–94. 1992;68:290–3. Load transfer characteristics of unilateral distal extension removable partial dentures with polyacetal resin supporting components. When abutments of questionable prognosis are present, a design should be chosen that would enable the partial denture to be adapted if such a tooth were lost. Maxillary distal-extension removable partial denture abutments with reduced periodontal support. 2009;54:31–7. During treatment planning of the RPD, the clinician must consider the biomechanics of the RPD as well as the patient’s comfort, esthetics, and prognosis of the abutments to withstand the forces. J Prosthet Dent. The direct or clasp retainers can be distinguished between tooth-supported (Class III and IV) and tooth-tissue-supported (Class I and II) RPDs. 2009;67:1941–6. 2013;57:109–12. It may be fixed (i.e. Multicentre prospective evaluation of implant-assisted mandibular bilateral distal extension removable partial dentures: patient satisfaction. Denture base color and characterization . These displacement forces must be taken into consideration during the design analysis process.2Creating resistance to this functional stress and displacement forces within our design is essential to the success of a definitive RPD. Kennedy’s method of classification is probably the most widely accepted system of classifying partially edentulous arches today. 1990;3:256–65. When we spend more time on case planning, our success ratio on these complex prosthetic cases will increase. Biomechanics of RPD. During function of an RPD, the prosthesis undergoes different types of stress. Robert Kreyer, CDT J Prosthodont Res. In the 1960s, Professor F. J. Kratochvil recognized the importance of biomechanics in removable partial denture (RPD) design and used these principles to develop a new design philosophy. Start studying biomechanics of RPD. Dent Clin North Am. biomechanics of rpd with movement in rpd rpd denture simple explanation for rpd denture design in removable partial denture.. this is the part of … St. Louis, MO: C.V. Mosby Co.; 1969. design workflow process. J Prosthet Dent. Bohnenkamp DM. Int J Prosthodont. T/F: need at least 2 planes of resistance. 2014;58:69–89. But however, removable partial denture (RPD) is still the primary treatment option from the patients’ view because an implant-supported dentures are relatively expensive from a financial point of view and require a … Discuss the importance of major connectors, minor connectors, direct retainers or clasps, and indirect retainers. St. Louis: Elsevier Mosby; 2011. J Dent Sci. 2008;21:50–2. Cingulum rests are ideally chevron shaped with the deepest point at the apex of the chevron and have a horizontal dimension of one-third the lingual surface of the tooth. In the 1960s, Professor F. J. Kratochvil recognized the importance of biomechanics in removable partial denture (RPD) design and used these principles to develop a new design philosophy. J Prosthet Dent. Comparison of vertical movement occurring during loading of distal-extension removable partial denture bases made by three impression techniques. J Oral Rehabil. DeVan, DDS, stated, our task is “the perpetual preservation of what remains rather than the meticulous restoration of what is missing.” It is with this thought that we study biomechanic design principles of removable partial dentures. A good rule is that more anterior tooth loss creating a larger posterior edentulous areas means more palatal coverage in major connector design. For a Class IV Mandibular RPD the most common is a lingual plate with a modified lingual bar extending to pre-molar or molar for clasping. During function of an RPD, the prosthesis undergoes different types of stress. Jiao T, Chang T, Caputo AA. In the 1960s, Professor F. J. Kratochvil recognized the importance of biomechanics in removable partial denture (RPD) design and used these principles to develop a new design philosophy. Resistance to functional stress and displacement forces is created through understanding 3 basic factors in RPD. He was one of the fi rst to recognize the importance of biomechanics in RPD design and used these principles to develop a whole new design philosophy. Kapur KK, Deupree R, Dent RJ, Hasse AL. In order to enhance communication with the dental laboratory, the definitive RPD design can be drawn in color on the laboratory work authorization form ( Fig. 2007;34:222–7. J Prosthet Dent. Class I partials are tooth and tissue supported. 4th ed. They assist in stabilizing the RPD against horizontal movement, splint the teeth they contact against movement, and act as auxiliary support for the major connector (Figure 13). Int J Prosthodont. Phoenix RD, Cagna DR, Defreest CF. Amount and location of retentive undercuts . c. Type and location of metal rests . Igarashi Y, Ogata A, Kuroiwa A, Wang CH. Removable partial denture (RPD): A partial denture that can … fulcrum line (horizontal axis) line connecting most posterior abutment teeth or abutments. The practitioner should begin with the understanding of how these three-dimensional functional forces (mechanics) act on the biological environment (abutment teeth, residual ridges, and alveolar mucosa). During the past few years, digital design capabilities have become a part of the RPD workflow. Presented at Study Group; 1986. T/F: tooth-tissue born RPDs will move . J Oral Maxillofac Surg. Most functional movement occurs during mastication and speech. Over 10 million scientific documents at your fingertips. J Oral Rehabil. (8,24) Therefore, the biological acceptability of denture design should be of primary concern and the mechanical elements of the appliance should not jeopardise the health of … Whether the dental technician is using a conventional or digital workflow, he or she still needs to understand the basic fundamentals of RPD design. In the 1960s, Professor F. J. Kratochvil recognized the importance of biomechanics in removable partial denture (RPD) design and used these principles to develop a new design philosophy. b. For a Class II Mandibular RPD, the most common major connector design is a lingual bar that has cross-arch stabilization to the dentate side of arch. This article will cover thee basic prosthodontic design concepts of a functional removable partial denture framework. Completed overlay RPD Implant-assisted overlay partial denture provides favorable biomechanics and also offers optimal esthetics for lip/cheek support and replace hard and soft tissue 29. Those who possess excellent knowledge in biology and bio-mechanic principles of RPD design plus digital solutions will have a true advantage in dental laboratories and prosthodontics of the future. As we go forward into this digital future of removable prosthetics, design options will be integrated into software based on variables present (Figures 19 and 20). Class II is a unilateral edentulous area located posterior to the remaining dentition, such as when all the teeth are present on one side of the mouth and all are missing on the opposite side. Periodontal considerations in removable partial denture treatment: a review of the literature. Removable partial denture design requires a dental technician to restore function, enhance esthetics, and promote longevity. In dental laboratory technology, we have been designing and manufacturing removable partial dentures (RPDs) with conventional processes for more than 50 years. For a Class II Maxillary RPD, the most common major connector is a wide palatal strap that connects the posterior edentulous sides together. Wheel and Axle Principle: (Rotation) The Partial denture can rotate along one of 3 planes: A. biomechanics in removable partial denture biomechanical considerations: the rpd and their associated structures are subjected to various forms of stress. J Prosthet Dent. These variables include condition of abutments such as clinical crown-to-root ratio, desirable and undesirable undercuts, rest preparation, inter-occlusal or inter-arch space, supporting tissues, and residual ridge anatomy (Figure 1 through Figure 3). 1. Not logged in Periodontal considerations in removable partial denture treatment: a review of the literature. Class III is a tooth-supported RPD. This is a preview of subscription content. Biomechanical analysis of distal extension removable partial dentures with different retainers. 7 O-ring retainers in position in the a superior and b inferior RPD Fig. Effect of direct retainer and major connector designs on RPD and abutment tooth movement dynamics. 2001a;14:164–72. Ball rests, also known as modified cingulum rests, are located mesial or distal to the natural cingulum. During treatment planning of the RPD, the clinician must consider the biomechanics of the RPD as well as the patient’s comfort, esthetics, and prognosis of the abutments to withstand the forces. The keys to success with removable partial dentures are proper clinical assessment of the oral condition, diagnostic mounted study casts, determining desirable and undesirable undercuts, proper tooth modification, impeccable impressions, accurate master casts, copious clinical and technical communication on design, and occlusal harmony (Figure 18). Sign up today! A horseshoe design for a major connector should be used in a Kennedy Class I to go around a palatal torus. Kawata T, Kawaguchi T, Yoda N, Ogawa T, Kuriyagawa T, Sasaki K. Effects of a removable partial denture and its rest location on the forces exerted on an abutment tooth in vivo. The author would like to thank European Chrome Dental Laboratory for providing images of their completed RPDs. J Oral Rehabil. Class III is a unilateral edentulous area with natural teeth located both anterior and posterior to it. An example is when the first or second pre-molar plus molars are missing on both sides of the arch. 2001b;14:164–72. Jorge JH, Giampaolo ET, Vergani CE, Machado AL, Pavarina AC, Cardoso de Oliveira MR. Clinical evaluation of abutment teeth of removable partial denture by means of the Periotest method. T Nowadays, the scientific research is more focused on the fixed prosthetics and mainly on dental implants. 1998;79:465–71. 1. Stress distribution and abutment tooth mobility of distal-extension removable partial dentures with different retainers: an in vivo study. The effect of various clasping systems on the mobility of abutment teeth for distal-extension removable partial dentures. use of RPD framework if a critical abutment is lost; placing rest seats, guide planes and undercuts on crowns to allow fabrication of an RPD later). These displacement forces must be taken into consideration during the design analysis process.2 Creating resistance to this functional stress and displacement forces within our design is essential to the success of a definitive RPD. Although many of these arches are now having implants placed in the edentulous areas for fixed partial dentures, it is important to understand methods of classification for removable partials. The basic prosthodontic design concepts of a functional removable partial denture framework will be discussed. Such clasps include bar designs such as RPI, RPA, roach, or modified roach. Biomechanics of Inclined Planes: The rest will ‘slip off’ the inclined rest seat However, flattening the rest seat will aid in the retention of the direct retainer on the tooth surface and resist horizontal forces 16. The patient who has paid for an RPD to restore compromised function or esthetics is unable to wear the unsuccessful appliance, so it is left in a drawer, and the patient increasingly does more dental damage to the remaining natural dentition. Biomechanics ofRemovable partial denture 2. 2014;58:115–20. Berg T, Caputo AA. To understand the variables in RPD design or form, we must consider function first. sources of vertical axis stability in RPD-denture base-maxillary major connector Chou TM, Eick JD, Moore DJ, Tira DE. Click Here! Goals in removable partial denture design are to restore function, enhance esthetics, and promote longevity. STUDY. Forgot your password? Edward Kennedy, DDS, said that removable partials resting mainly on a compressible base over soft tissue must be so designed as to overcome excessive stresses of mastication and to prevent external forces on natural teeth or crowns that have attachments or now implants placed in them. J Dent Sci. The Kennedy Classification System13 utilizes 4 classes of partially edentulous tooth loss: Class I is a bilateral edentulous area located posterior to the remaining dentition. Jing Zhao, Xinzhi Wang, in Advanced Ceramics for Dentistry, 2014. Leupold RJ, Flinton RJ, Pfeifer DL. Type of clasps . Abutment, tooth, and occlusal modifications should be a routine part of clinical RPD protocols (Figure 4). Within this definition of provisional or interim prostheses, removable partials dentures such as stayplates, acrylic partials, and flexible-type partials are included. Removable partial dentures are defined as any prosthesis that replaces some teeth but not all in a partially edentulous arch and can be removed at will by the patient. For a Class III Maxillary RPD, the most common major connector is a single palatal strap that connects the edentulous area of the arch with the distal abutment to the dentate side. All too often, dental laboratory technicians receive removable partial denture cases that have been planned improperly, which results in a DRPD (Drawer Removable Partial Denture). Biomechanics of Removable Partial Dentures. This dental damage may include movement or super eruption of teeth, bone loss, decreased vertical dimension of occlusion, impaired phonetics, and loss of the confidence to smile or laugh. Aridome K, Yamazaki M, Baba K, Ohyama T. Bending properties of strengthened Ti-6Al-7Nb alloy major connectors compared to Co-Cr alloy major connectors. Although horseshoe major connectors are popular, they are less desirable biomechanically due to excessive flexibility. 1999;26:111–6. Prosthodontic Consultant adequate bone support. 2008;35:810–5. The goal, as described by James S. Brudvik, DDS, is to “make every attempt to cover as little of the gingival tissues as possible.” Excessive gingival coverage is associated with increased plaque formation and should be avoided whenever possible. Cupertino, California. Study 16 Lec 5 RPD Biomechanics flashcards from on StudyBlue. Influence of clasp design of distal extension removable partial dentures on the periodontium of the abutment teeth. © 2020 Springer Nature Switzerland AG. pp 25-35 | If inadequate lingual depth is present, a high frenum attachment exists, or where residual ridges have excessive vertical resorption, then a lingual plate is chosen. Material and Methods : A 36 year old female patient, with a partially edentulous atrophic maxilla was submitted to maxillofacial surgery to correct a skeletal class III malocclusion in June 2008 and 1 year after rehabilitated with implants and a RPD at … In particular, the design and function of definitive RPDs that use a rigid framework for retention, support, and stability in the partially edentulous oral environment are crucial to understand. Class IV RPDs have other challenges that include esthetics and function when incising food during mastication (Figure 16). 1991;66:343–9. a. The most common Class II is when a pre-molar and molars are missing on one side and present on the other side of the arch. It is supported by the teeth and/or the mucosa. Queries for the author may be directed to jromano@aegiscomm.com. Retention is the resistance to vertical movement away from tissues and is provided by direct and indirect retainers. J Prosthet Dent. 2. Jacobson T. RPD Design and Treatment Planning. With mandibular Kennedy Class I removable partial dentures, the most common is a lingual plate or lingual bar. A RPD associated with implants and metal-ceramic milled crowns can offer excellent esthetics, and will improve function and biomechanics, at a reduced cost. The emphasis of this article is on design and function of definitive RPDs that use a rigid framework for retention, support, and stability in the partially edentulous oral environment. Part of Springer Nature. Figure 5 through 13 illustrate different situations and variables to consider during the diagnostic case planning process. As M.M. Circumferential clasps such as round wrought wire with PGP (platinum-gold-palladium) or CrCo (chromium cobalt) provide retention and self-releasing during function and are an excellent option for distal extension bases. 1998;80:58–66. Clin Oral Implants Res. J Prosthodont Res. The most common Class IV removable partial is when the centrals and laterals are missing while all other teeth are present in the mouth. 4. Cite as. Learn vocabulary, terms, and more with flashcards, games, and other study tools. For a Mandibular Class III RPD, the major connector of choice is a lingual bar with lingual plating reserved for inadequate lingual depth, high frenum attachment, or future anterior tooth loss. Itoh H, Caputo AA, Wylie R, Berg T. Effects of periodontal support and fixed splinting on load transfer by removable partial dentures. design: retention, stability, and support. Itoh H, Baba K, Aridome K, Okada D, Tokuda A, Nishiyama A, Miura H, Igarashi Y. The components of an RPD are major connectors, minor connectors, direct retainers or clasps, and indirect retainers.4 Various designs of major connectors may be used for RPDs, depending on the maxillae or mandible, edentulous areas, and anatomical arch form. With a Class I and II tooth-tissue-supported RPD design, the retainer clasp should provide stress breaking from the distal abutment. Biomechanics of removable partial denture • Mechanics of Movement • In the human body, movement can occur in any of the three fundamental planes: horizontal, sagittal, or frontal planes. J Prosthet Dent. Wismeijer D, Tawse-Smith A, Payne AG. Horseshoe major connectors are used although not desirable due to flexibility and increased anterior palatal coverage. hold the denture in place. McCracken’s removable partial prosthodontics. 12th ed. These stress forces during function include dislodging, horizontal, torsional, and vertical displacement forces. their ability to resist them depend on: direction, duration, magnitude and frequency of the stress (force) being applied onto the denture and denture bearing areas J Oral Rehabil. Taylor DT, Pflughoeft FA, McGivney GP. Hosman HJ. Budtz-Jorgensen E, Bochet G. Alternate framework designs for removable partial dentures. Thus, the biomechanic design principles of RPDs are important. Technicians who accept these new digital tools will always be the masters of case design and manufacturing processes. If our goal is to provide optimal removable prosthetic care and treatment for these dentally compromised patients, then a proper clinical and technical assessment of the oral condition is essential to a successful RPD. biomechanics in rpd 1. INTRODUCTION Biomechanics basically deals with application ofmechanical principles to biological tissues. Channel rests extend from the marginal ridge to the long axis of an abutment tooth. This "RPI system"-a clasp assembly consisting of a rest, a proximal plate, and an I-bar retainer-changed how clinicians approach partial denture design and is now used throughout the world. Understand the variables in RPD design and form. TRUE - better yet, have 3 planes of resistance. The author reports no conflicts of interest associated with this work. 2005;32:823–9. This class of RPD is the most common for partially edentulous patients. Biomechanics of Removable of Partial Dentures - Free download as Powerpoint Presentation (.ppt / .pptx), PDF File (.pdf), Text File (.txt) or view presentation slides online. Part I: comparisons of five-year success rates and periodontal health. This "RPI system"—a clasp assembly consisting of a rest, a proximal plate, and an I-bar retainer—changed how clinicians approach partial denture design and is now used throughout the world. Tebrock OC, Rohen RM, Fenster RK, Pelleu Jr GB. New York, NY: Dental Items of Interest Publishing Company; 1928. 8 Clinical final aspect Fig. Minor connectors include all connecting links between the major connector or base of the RPD and all other units of the partial to include denture base retentive elements. PLAY. As with FPDs, the RPD can also restore an incomplete dentition, but with broader indications because of not-so-strict prerequisites. 9 Radiography final aspect Class III and IV RPD retainer clasp designs for tooth-supported RPDs include circumferential or Akers’ clasps and rotational path partials for exceeding esthetic expectations. 3.3.3 Removable Partial Dentures. Removable partial denture (RPDs) as the names suggests, is not fixed permanently in the patient’s oral cavity and can be easily removed by the patient. For a Class IV Maxillary RPD, the most common major connector is a horseshoe design. Carr AB, Brown DT. Tooth numbers . Henderson D and Steffel V. McCracken’s Removable Partial Denture Construction. On the mandibular arch, major connectors should be 3-4 mm away from the gingival margins unless a lingual plate is indicated (Figure 14). Grossmann Y, Nissan J, Levin L. Clinical effectiveness of implant-supported removable partial dentures: a review of the literature and retrospective case evaluation. 3. J Prosthet Dent. In the 1960s, Professor F. J. Kratochvil recognized the importance of biomechanics in removable partial denture (RPD) design and used these principles to develop a new design philosophy. A removable partial denture (RPD) is not rigidly attached to the teeth, and therefore there is a potential for movement of the denture when these functional movements create forces on the teeth and denture. 2012;7:7–13. The distal abutment clasp would ideally have a self-releasing design for disengagement from the tooth during vertical movement under function. Horseshoe designs are commonly used as well, although they do not provide the support needed for a bilateral distal extension base RPD. Presented at Study Group; 2003. Ogata K, Miyake T, Okunishi M. Longitudinal study on occlusal force distribution in lower distal-extension removable partial dentures with circumferential clasps. Petridis H, Hempton TJ. 1994;72:268–82. DeBoer J. Akaltan F, Kaynak D. An evaluation of the effects of two distal extension removable partial denture designs on tooth stabilization and periodontal health. Biomechanics is the study of the structure and function of biological systems by means of mechanics. This classification is most common when a second molar is present and the pre-molars plus second molar are missing. Support is the resistance to tissue movement (vertical or horizontal) of an RPD and is provided by rests, denture bases, and major connectors. Forces on an RPD are the result of a composite of forces arising from three principle fulcrums. 1979;41:511–6. The effects on function of distal-extension removable partial dentures as determined by occlusal rest position. The RPD that successfully functions within a partially edentulous oral environment has been properly case planned with mounted diagnostic study casts.1 Clinical and technical evaluation of mounted study casts enables technicians to collect data to understand variables on the existing partially edentulous condition. ... implants or fixed partial denture. The glossary of prosthetic terms. Removable partial dentures: clinical concepts. 1982;47:120–5. Int J Prosthodont. Petridis H, Hempton TJ. Chou TM, Caputo AA, Moore DJ, Xiao B. Photoelastic analysis and comparison of force-transmission characteristics of intracoronal attachments with clasp distal-extension removable partial dentures. 50.62.208.38. Fulcrum On Horizontal Plane: Extends through the principle abutments.