DOCSLIB.ORG

Rehabilitation of the Worn Dentition

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Rehabilitation of the Worn Dentition CLINICAL Rehabilitation of the worn dentition Nancy Ward, of the Pankey Institute Visiting Faculty presents a case report integrating restorative and orthodontic treatment approaches here are many challenges when treating posterior slide into maximum intercuspation adult patients. Decreased cell turnover, was evident. 4-5 mm pockets in between the Tno potential of growth modification, first and second molars were also noted. The complicated medical histories, and previous oral patient was referred for periodontal treatment disease (periodontal disease, caries, tooth wear, where the periodontal condition was stabilised temporomandibular dysfunction) have been prior to initiating any further treatment. reported as major considerations when treating Problem list: adultsREF1. In adults, often compromises have • Severe wear of the anterior teeth to be made, especially in terms of occlusion • Supra-eruption of the attachment and anterior coupling when the foundation apparatus around the incisors due (ie occlusal relationships) are not going to to wear of the incisal edges be changed. Without proper alignment: • Increased overjet • Poorly aligned teeth can create abnormal Figure 1a: Pre-trial smile • Class II Division 2 with lateral force and stress on surrounding narrow arches (Figure 2). teeth and periodontal structuresREF2 Aims of Treatment: • Severe bruxism and wear of anterior teeth a. Create a Class I canine relationship can cause the attachment apparatus to b. Level align and rotate teeth extrude with the wear of the incisorsREF3 c. Round the arches • Periodontal surgery is often needed to d. Intrude upper central incisors to establish proper gingival architecture create proper gingival architecture • Alignment of the teeth prior to restorative e. Proper alignment of the upper dentistry enables the establishment central and lateral incisors creating of a physiologic occlusion space for restorative material. • Alignment also allows for minimally To create a physiologic occlusionREF4, invasive restorative dentistry. the following principles were to be followed: This case report highlights a multi-disciplinary Figure 1b: Trial smile Anterior View (by Dr. Jhonson Haygood • Maximum number of posterior teeth Pankey Composite Course) approach to treating an adult patient with touch simultaneously in centric relation severe wear on the anterior teeth. arc of closure with the occlusal forces directed down the long axes of the teeth Case presentation • When force is applied no teeth are Virginia is a very outgoing person who loves to moved and the jaw does not deviate be around people. She was embarrassed about • Posterior teeth disoccluded by anterior her smile. A family member told her that she teeth in excursive movements looked like a vampire, which prompted her to • Condyles seated on the disc in their most seek advice. Economics was a major concern superior, anterior, medial unstrained position. to Virginia and she therefore volunteered to have a trial smile done at a composite course Treatment options (Figure 1a, 1b, 1c). The trial smile showed her 1. Veneers from UR6 to UL6, the possibilities of what could be achieved Figure 1c: Trial smile Profile View with no orthodontic treatment, as shown with the trial smile Nancy Ward DDS, MAGD qualified from 2. Orthodontic treatment without University of Maryland, Baltimore College with a cosmetic make over. The trial smile surgery, creating a Class 2 Division 1 of Dental Surgery and went on to gain a was used to establish incisal display when occlusion without anterior coupling and Mastership in the Academy of General Dentistry the lips were at rest and also showed the accepting the increased overjet, followed and the status of Premier Provider for Invisalign. architecture of the gingival display (Figure 1b). by veneers on the upper incisors. Dr Ward completed the continuums at the 3. Orthodontic treatment including the LD Pankey Institute in the late 1980’s. She has Comprehensive Exam extraction of UL4 cantilever and UR4 to allow been a member of the visiting faculty at the A comprehensive exam revealed missing retraction of the anterior teeth to create a Pankey Institute since 1995 and served on the UR8, UL4, UL8, LL8 and LR8. The patient Class I canine relationship, with simultaneous foundation board since 1990. She has lectured for Align Technology at both its GP Summits had lost UL4 which was replaced with a mesialisation of the upper premolars and and GP Forums. bridge cantilevered from the UL5. The patient molars to close any residual spaces. Intrusion www.pankey.org had no other restorations. A large centric of the severely worn upper central incisors interference was noted and an 8mm anterior/ could also be incorporated to allow bonding May 2014 Orthodontic Practice 35 CLINICAL Figure 2: Pre-treatment photographs in maximum intercuspation of the upper incisors (composite bonding Initially, the patient used the CII elastics or veneers). Fixed appliances and Invisalign running from upper 3s to lower 6s. When the (with the use of auxillaries) were provided upper 7s started mesialising (aligner 19) in this as treatment options to the patient. case, the patient was instructed to start wearing 4. Orthodontic/orthognathic surgery the elastics in a CIII direction, from lower 3s involving rounding of the arch, leveling and to the upper 7s. The combination of both CII alignment of the gingival heights, followed and CIII elastics staged at different points in the by orthognathic mandibular advancement treatment allowed for the extraction spaces to to create a Class 1 canine and molar be closed without mesial tipping of the molars. relationship. This would then be completed Vertical rectangular attachments with veneers on the upper incisors. were placed on the upper 6s to help with the translation of these teeth to close Treatment overview the extraction spaces (Figure 3). The patient opted not to have orthognathic Because optimised attachments could surgery and proceeded with treatment option 3. not be combined with button cutouts on The UR4 was extracted. The cantilever UL4 was the upper 3s, due to insufficient space on sectioned. Invisalign treatment was carried out with the use of auxillaries (buttons were placed on canines and first molars to run Class II and Class III elastics). Both arches were rounded out Figure 4: Use of occlusal markings on the study models to show the centric by buccal tipping of the premolars and molars. record. The upper central incisors were intruded so that the gingival margins of the upper central the aligners for both features, the optimised incisors matched the gingival margin levels attachments were removed and replaced with of the upper lateral incisors and canines thus conventional vertical rectangular attachments. avoiding the need for crown lengthening. The elastics were worn from the outset, ¼” The CC treatment plan included U33/ 4oz. The patient was very compliant with elastic L12 number of aligners, resulting in a wear, only removing the elastics when eating. treatment length of 15.5 months. The The elastics were changed three times a day. patient lived 1,800km away and could only My top tips for setting the occlusion be seen three times during the treatment. in centric relation (CR) on the CC: Optimised and conventional attachments • Record a centric relation bite using a were placed on nine teeth. Intrusion of 5mm facebow and have the models mounted onto was achieved with the use of the 20 aligners. Figure 3: Conventional attachments on upper 6s to prevent tipping and on a semi-adjustable articulator (Kavo). • Mark The upper anterior teeth were over-retracted upper 3s to accommodate button cutouts. Note pontic on upper 4s, which the first point of the occlusion on the stone in the CC, so that the lingual root torque will be masked with composite or Align’s proprietary pontic kit material models. Thereafter, photograph the mounted could be requested in the refinement. until the spaces are closed models using the same intraoral series of 34 Orthodontic Practice May 2014 CLINICAL Figures 5a: Clinical photograph and Clincheck in maximum intercuspation Figure 5b: Study model vs Clincheck in centric relation photographs as per the original submission Conclusion (Figure 4). These photographs can be emailed By adopting the use of a trial smile, the to Align Technology, which will allow the patient was able to visualise the end result technician to set the occlusion in CR. if she opted for some type of treatment. • Another option would be to mark Invisalign, in conjunction with additive Figure 6: Pre-refinement and pre-bonding photos (post- the patient’s occlusion in the mouth using bonding proved to be an excellent treatment Invisalign) articulating paper and photograph the option for this patient who expressed some patient’s occlusal shots showing the occlusal financial restrictions. The patient has the markings. It is important to photograph the option to have veneers on the upper incisors lateral and facial views in centric as this allows at a later date. The use of Invisalign to the technician to see the distance between correct the gingival contours eliminated the teeth in each arch in centric relation. the need for periodontal surgery. Treating Intraoral photographs, photographs an extraction case with Invisalign and of the study models and CC screenshots auxiliaries is possible using the tips provided in maximum intercuspation and centric in the main report. Where necessary, use relation are shown in Figures 5a and 5b. the Clincheck software program to re- Figure 7: Centric relation/occlusion - pre-equilibration and bonding, The pre-refinement photographs establish centric relation of which some highlighting the spaces around the lateral incisors to allow for additive are shown in Figure 6. guidance on this has also been provided. bonding Following the initial set of aligners, the The integration of a multi-disciplinary patient had composite bonding carried out approach (perio-ortho-restorative) was on the upper 3-3 to test the length of the key to the success of this treatment.
Load more

Recommended publications
  • Changing Vertical Dimension: a Solution Or Problem? by Peter E
    Continuing Education Changing Vertical Dimension: A Solution or Problem? by Peter E. Dawson, DDS Abstract Much of what dentists know about the vertical dimension of occlusion (VDO) has changed from the dogma of a few years ago. Dentists who understand the fundamental concepts of VDO can use those concepts to great advantage in treatment planning. Failure to understand can (and often does) lead to missed diagnoses, failed treatment outcomes, and serious examples of unnecessary overtreatment. This article explains some of the principles that make changes in VDO advantageous and predictable, and exposes some of the misconceptions that are problematical. Learning Objectives After reading this article, the reader should be able to: recognize the importance of vertical dimension as it applies to treatment planning for anterior teeth. discuss why posterior segmental bite-raising appliances are contraindicated. describe how changes in vertical dimension affect buccolingual relationships of posterior teeth. explain why the effect of changing vertical dimension is best studied on face-bow mounted diagnostic casts. The Concept of Balance The equilibrium of the entire masticatory system is dependent on balance.1 The mandible at rest is balanced between the resting lengths of the elevator muscles and the depressor muscles (Figure 1 View Figure). Anything that affects the resting length of either group of opposing muscles can affect the critical relationship of the mandible with the maxilla at the resting position. Because the teeth are not in contact at the rest position and the mandible-to-maxilla relationship is not consistent,2,3 the rest position is not an accurate determinant of the jaw-to-jaw relationship at maximum intercuspation.
    [Show full text]
  • Opening Vertical Dimension: How Do You Do It? by Evelyn Shine, DDS
    Opening vertical dimension: how do you do it? By Evelyn Shine, DDS Introduction Vertical dimension of occlusion is used to denote the superior inferior relationship between the maxilla and the mandible when teeth are in maximum intercuspation. When vertical dimension is decreased significantly, either via loss of teeth or parafunction, the result can be a collapsed bite. RELATED READING | Harmony in prosthodontics As vertical dimension is lost, the proportions of the face are altered; one’s chin becomes recessed, the lower half of the face may look short, and the angles of the mouth can develop chelitis. Loss of vertical dimension results in facial collapse, wrinkles by the nasolabial fold, and appearance of compressed and thin lips, which makes one appear older. RELATED READING | All-On-4 treatment option: a case report Dentures can be fabricated to correct a collapsed bite and increase vertical dimension in patients with missing teeth. Alternatively, vertical dimension can also be increased via an acrylic bite plate and/or fixed prosthodontic work. Case report A 60-year-old male patient presents to the dental office with the following chief complaint: “My lower teeth are getting shorter.” Upon visual extraoral examination, the patient had difficulty keeping his lower jaw still at all times; upon sitting still, the patient’s jaw tremors from side to side. It appears as though the patient may have Parkinson’s disease; however, the patient states that his medical conditions only include diabetes and hypertension. He is taking lisinopril to control his blood pressure. He denied tremors or Parkinson’s. Initial dental exam Fig.
    [Show full text]
  • A Guide to Complete Denture Prosthetics
    A Guide to Complete Denture Prosthetics VITA shade taking VITA shade communication VITA shade reproduction VITA shade control Date of issue 11.11 VITA shade, VITA made. Foreword The aim of this Complete Denture Prosthetics Guide is to inform on the development and implementation of the fundamental principles for the fabrication of complete dentures. In this manual the reader will find suggestions concerning clnical cases which present in daily practice. Its many features include an introduction to the anatomy of the human masticatory system, explanations of its functions and problems encountered on the path to achieving well functioning complete dentures. The majority of complete denture cases which present in everyday practice can be addressed with the aid of knowledge contained in this instruction manual. Of course a central recommendation is that there be as close as possible collaboration between dentist and dental technician, both with each other and with the patient. This provides the optimum circumstances for an accurate and seamless flow of information. It follows also that to invest the time required to learn and absorb the patient’s dental history as well as follow the procedural chain in the fabrication procedure will always bring the best possible results. Complete dentures are restorations which demand a high degree of knowledge and skill from their creators. Each working step must yield the maximum result, the sum of which means an increased quality of life for the patient. In regard to the choice of occlusal concept is to be used, is a question best answered by the dentist and dental technician working together as a team.
    [Show full text]
  • Effect of Centric Interference on Canine Tooth Wear Andrey Gaiduchik
    Loma Linda University TheScholarsRepository@LLU: Digital Archive of Research, Scholarship & Creative Works Loma Linda University Electronic Theses, Dissertations & Projects 9-2018 Effect of Centric Interference on Canine Tooth Wear Andrey Gaiduchik Follow this and additional works at: http://scholarsrepository.llu.edu/etd Part of the Orthodontics and Orthodontology Commons Recommended Citation Gaiduchik, Andrey, "Effect of Centric Interference on Canine Tooth Wear" (2018). Loma Linda University Electronic Theses, Dissertations & Projects. 512. http://scholarsrepository.llu.edu/etd/512 This Thesis is brought to you for free and open access by TheScholarsRepository@LLU: Digital Archive of Research, Scholarship & Creative Works. It has been accepted for inclusion in Loma Linda University Electronic Theses, Dissertations & Projects by an authorized administrator of TheScholarsRepository@LLU: Digital Archive of Research, Scholarship & Creative Works. For more information, please contact [email protected]. LOMA LINDA UNIVERSITY School of Dentistry in conjunction with the Faculty of Graduate Studies ____________________ Effect of Centric Interference on Canine Tooth Wear by Andrey Gaiduchik ____________________ A Thesis submitted in partial satisfaction of the requirements for the degree Master of Science in Orthodontics and Dentofacial Orthopedics ____________________ September 2018 © 2018 Andrey Gaiduchik All Rights Reserved Each person whose signature appears below certifies that this thesis in his opinion is adequate, in scope and quality, as a thesis for the degree Master of Science. , Chairperson V. Leroy Leggitt, Professor of Orthodontics and Dentofacial Orthopedics , Co-Chairperson L. Parnell Taylor, Professor of General Dentistry Joseph M. Caruso, Professor of Orthodontics and Dentofacial Orthopedics iii ACKNOWLEDGEMENTS I would like to express my appreciation for all those who helped me complete my thesis.
    [Show full text]
  • Prediction of Root Form Using Crown Data: Mandibular Left First Premolar
    Loma Linda University TheScholarsRepository@LLU: Digital Archive of Research, Scholarship & Creative Works Loma Linda University Electronic Theses, Dissertations & Projects 9-2017 Prediction of Root Form Using Crown Data: Mandibular Left irsF t Premolar Matthew E. Durschlag Follow this and additional works at: http://scholarsrepository.llu.edu/etd Part of the Orthodontics and Orthodontology Commons Recommended Citation Durschlag, Matthew E., "Prediction of Root Form Using Crown Data: Mandibular Left irF st Premolar" (2017). Loma Linda University Electronic Theses, Dissertations & Projects. 463. http://scholarsrepository.llu.edu/etd/463 This Thesis is brought to you for free and open access by TheScholarsRepository@LLU: Digital Archive of Research, Scholarship & Creative Works. It has been accepted for inclusion in Loma Linda University Electronic Theses, Dissertations & Projects by an authorized administrator of TheScholarsRepository@LLU: Digital Archive of Research, Scholarship & Creative Works. For more information, please contact [email protected]. LOMA LINDA UNIVERSITY School of Dentistry in conjunction with the Faculty of Graduate Studies __________________ Prediction of Root Form Using Crown Data: Mandibular Left First Premolar by Matthew E. Durschlag __________________ A thesis submitted in partial satisfaction of the requirements for the degree Master of Science in Orthodontics and Dentofacial Orthopedics __________________ September 2017 2017 Matthew Durschlag All Rights Reserved Each person whose signature appears below certifies that this thesis in his opinion is adequate, in scope and quality, as a thesis for the degree Master of Science. , Chairperson Joseph Caruso, Professor of Orthodontics and Dentofacial Orthopedics Mark K. Batesole, Assistant Professor of Orthodontics and Dentofacial Orthopedics Rodrigo Viecilli, Associate Professor of Orthodontics and Dentofacial Orthopedics iii ACKNOWLEDGEMENTS I would like to express my gratitude to Dr.
    [Show full text]
  • Differences Between Centric Relation and Maximum Intercuspation As Possible Cause for Development of Temporomandibular Disorder Analyzed with T-Scan III
    Published online: 2019-09-23 Original Article Differences between centric relation and maximum intercuspation as possible cause for development of temporomandibular disorder analyzed with T‑scan III Zana D. Lila‑Krasniqi1, Kujtim Sh. Shala1, Teuta Pustina‑Krasniqi1, Teuta Bicaj1, Linda J. Dula1, Ljuben Guguvčevski2 1Department of Prosthetics, Faculty of Medicine, School of Dentistry, Pristina, Kosovo, Correspondence: Dr. Zana D. Lila‑Krasniqi 2Department of Prosthetics, Faculty of Dentistry, Email: [email protected] Skopje, Macedonia ABSTRACT Objective: To compare subjects from the group with fixed dentures, the group who present temporomandibular disorders (TMDs) and a control group considering centric relation (CR) and maximum intercuspation (MIC)/habitual occlusion (Hab. Occl.) and to analyze the related variables also compared and analyzed with electronic system T-scan III. Materials and Methods: A total of 54 subjects were divided into three groups; 17 subjects with fixed dentures, 14 with TMD and 23 controls‑selection based on anamnesis-responded to a Fonseca questionnaire and clinical measurements analyzed with electronic system T-scan III. Occlusal force, presented by percentage (automatically by the T-scan electronic system) was analyzed in CR and in MIC. Results: Data were presented as mean ± standard deviation and differences in P < 0.05 were considered significant. After measurements of the differences between CR and MIC in the three groups were noticed varieties but the P > 0.05 it was not significant in all three groups.Conclusion: In our study, it was concluded that there are not statistically significant differences between CR and MIC in the group of individuals without any symptom or sign of TMD although there are noticed in the group with TMD and fixed dentures disharmonic relation between the arches with overload of the occlusal force on the one side.
    [Show full text]
  • Parameters of Care for the Specialty of Prosthodontics (2020)
    SUPPLEMENT ARTICLE Parameters of Care for the Specialty of Prosthodontics doi: 10.1111/jopr.13176 PREAMBLE—Third Edition THE PARAMETERS OF CARE continue to stand the test of time and reflect the clinical practice of prosthodontics at the specialty level. The specialty is defined by these parameters, the definition approved by the American Dental Association Commission on Dental Education and Licensure (2001), the American Board of Prosthodontics Certifying Examination process and its popula- tion of diplomates, and the ADA Commission on Dental Accreditation (CODA) Standards for Advanced Education Programs in Prosthodontics. The consistency in these four defining documents represents an active philosophy of patient care, learning, and certification that represents prosthodontics. Changes that have occurred in prosthodontic practice since 2005 required an update to the Parameters of Care for the Specialty of Prosthodontics. Advances in digital technologies have led to new methods in all aspects of care. Advances in the application of dental materials to replace missing teeth and supporting tissues require broadening the scope of care regarding the materials selected for patient treatment needs. Merging traditional prosthodontics with innovation means that new materials, new technology, and new approaches must be integrated within the scope of prosthodontic care, including surgical aspects, especially regarding dental implants. This growth occurred while emphasis continued on interdisciplinary referral, collaboration, and care. The Third Edition of the Parameters of Care for the Specialty of Prosthodontics is another defining moment for prosthodontics and its contributions to clinical practice. An additional seven prosthodontic parameters have been added to reflect the changes in clinical practice and fully support the changes in accreditation standards.
    [Show full text]
  • Articulator Selection for Restorative Dentistry
    FIXED PROSTHODONTICS OPERATIVE DENTISTRY DAVID E. BEAUDREQU, SAMUEL E.GUYER, WILLIAM LEFKOWITZ, Section editors Articulator Selection for Restorative Dentistry Sumiya Hobo, D.D.S.,M.D.S.,*Herbert T. Shinningburg, Jr., D.D.S.,** and Lowell D. Whitsett, D.D.S.*** Tokyo, Japan, and Oklahoma City, Okla. The articulator selected, and even more importantly, the skill and care with which it is used, have a direct bearing on the success of fixed or removable restorations. Were the dentist’s only concern the relationship of the opposing teeth at the point of maximum intercuspation, both the design and the use of an articulator would be greatly simplified. Since the position of intercuspation is static, the articulator need act only as a regid hinge-little more than a handle for the cast. The mandible, however, does not act as a simple hinge. Rather, it is capable of rotation about axes in three planes. The occlusal morphology of any restoration for the mouth must accommodate the free passage of the opposing teeth without interfering with the movement of the mandible. Because of their potential for producing disease, occlusal interferences must not be incorporated into restorations placed by the dentist. One method of preventing this problem has been to use fully adjustable articulators which duplicate the mandibular movements with a high degree of precision. Treatments using these articulators are time-consuming and demand great skill by the dentist and the technician. As a result, the cost of such treatment does not make it feasible for most smaller routine treatment plans. Most single crowns and simple fixed partial dentures are fabricated on small hinge articulators that have limited ability to duplicate mandibular movement or none at all.
    [Show full text]
  • 12 Occlusion and Removable Prosthodontics
    Ch12.qxd 10/10/03 11:55 AM Page 111 Occlusion and removable 12 prosthodontics R. Jagger – Occlusal analysis Synopsis – Clinical stages Occlusal considerations for removable – Onlay dentures prostheses are essentially the same as for • Complete dentures fixed restorations. – Occlusion for complete dentures The approach to establishing occlusion for – Occlusal vertical dimension removable partial dentures is usually – Artificial teeth conformative. Partial dentures should not – Balanced occlusion transmit excessive forces to supporting – Lingualised occlusion tissues nor interfere with any contacts in – Occlusion and patient satisfaction intercuspal position or in functional – Clinical stages movements. Occasionally a reconstructive approach using onlays is used. Occlusion for complete dentures has three significant differences: Good occlusal practice for removable dentures is very similar to that described for fixed prostheses. • The absence of natural teeth in edentulous Partial dentures should not transmit excessive forces to patients may present significant difficulties supporting tissues nor interfere in intercuspal position or in determining an acceptable occlusal in functional movements. The occlusal form is usually vertical dimension. conformative with the natural teeth. Occasionally a • Complete denture occlusion is always a reconstructive approach using onlays is used. Occlusion reorganised occlusion. for complete dentures, however, has three significant • Absence of teeth produces problems of differences: denture stability (resistance
    [Show full text]
  • The International Journal of Periodontics & Restorative Dentistry
    Ohyama.qxd 12/7/06 4:38 PM Page 60 The International Journal of Periodontics & Restorative Dentistry Ohyama.qxd 12/7/06 4:38 PM Page 61 61 Recreating an Esthetic Smile: A Multidisciplinary Approach Hiroe Ohyama, DMD, MMSc, PhD* The esthetic restoration/rehabilitation Shigemi Nagai, DDS, MS, PhD* of a patient with a functionally com- Hiro Tokutomi, RDT** promised dentition frequently involves Michael Ferguson, DMD*** a multidisciplinary approach. The suc- cessful integration of esthetics and function does not emerge by chance, but rather as a result of the meticulous development of clearly defined ana- Today’s dental patients are demanding a youthful, attractive smile. The esthetic tomic parameters and their subse- rehabilitation of patients with functionally compromised dentitions frequently quent incorporation into the design of involves a multidisciplinary approach. The realization of esthetic objectives in mul- the prosthesis.1–4 tidisciplinary cases represents a considerable clinical challenge. To a great extent, The restorative and periodontal proper case selection and careful multidisciplinary treatment planning can govern the predictability of procedures. A team approach that includes the clinicians, the elements, such as incisal length, incisal laboratory technician, and the patient is essential to achieve the desired results. plane, incisal profile, incisal display, This clinical report demonstrates a successful multidisciplinary approach to re- tooth shape and color, tooth propor- creating an esthetic smile of a patient whose anterior maxillary dentition had been tion, tooth-to-tooth proportions, gin- functionally and esthetically compromised by prosthetic and periodontal prob- gival architecture, and gingival display lems. (Int J Periodontics Restorative Dent 2007;27:61–69.) should be considered in the creation of a pleasing smile.
    [Show full text]
  • Occlusion in Complete Dentures
    1 OCCLUSION IN COMPLETE DENTURES C P Owen Introduction Occlusion has been described as the most important subject in all the disciplines of dentistry, and for good reason, because the way the teeth come together, and function together, is as important to most of us now as it was to our ancestors, who lived on diets much more difficult to cope with. When, as dentists, we are faced with the problem of replacing occlusal surfaces, either by restorations in natural teeth, or replacement of some or all of the teeth, then a thorough knowledge of the way teeth come together and function together, is essential. Occlusion has unfortunately also been described as one of the most confusing subjects in all the disciplines of dentistry (mostly by each generation of dental students). Attempts to understand occlusion have ranged from the mechanical, mathematical and geometrical analysis of tooth contact and jaw movement, to the biological and functional analyses based on the behaviour of natural dentitions under different environmental (mostly dietary) conditions. All of these analyses have their place but they need to be brought together into a unified concept, and this is rarely done. However, there are rational ways to study occlusion, and studying occlusion in complete dentures is a good starting point, because of the need to place an entire dentition within a system so that the edentulous patient can once again function with the minimum of discomfort and the maximum possible efficiency. Natural occlusion and artificial occlusion Development of the occlusion The evolution and development of the dentition and temporomandibular joint is a useful study in that it gives us clues as to how our present dentition functions.
    [Show full text]
  • Principles of Removable Partial Denture Design
    د.فائزة Lec. 23 Prosthodontics Principles of removable partial denture design The supporting structures for removable partial dentures (abutment teeth and residual ridges) are living things and are subjected to forces. The ability of living things to tolerate force is dependent upon the magnitude or intensity of the forces. The forces occurring through the removable partial denture can be widely distributed, directed, and minimized by the selection, the design and the location of components of removable partial denture and by developing a harmonious occlusion. Types of partial dentures 1. Removable partial denture, which includes the cobalt chromium and acrylic removable partial denture. 2. Fixed partial denture. 3. Implant supported partial denture, this could be fixed (implant retained partial denture) or removable (implant support partial denture). General principle 1. Utilize what is present. Whenever possible, select a design that fits the teeth and soft tissues, rather than choosing one that requires tissue alteration. The goal is to avoid gross, unnecessary preparations. 2. Minimize the framework elements. Whenever possible, the fewest number of minor connectors should be used. This decreases the potential for plaque adhesion. [3rd year / College of Dentistry/University of Baghdad (2018-2019)] Page 1 3. Plan for future. Planning for the future might involve designing castings with rest seats and guiding planes so they may subsequently be used as partial denture abutments, if required in the future. 4. Consider caries susceptibility. Cast clasps cover more tooth surface than wrought clasps. The latter would be preferred if caries incidence is higher than usual. 5. Avoid placing rest seats or guiding planes on direct restorations such as amalgam.
    [Show full text]