Removable Partial Denture Design Research Articles

Clinical evaluation of removable partial dentures on the periodontal health of abutment teeth: a retrospective study.

The aim of this retrospective study was to evaluate the effect of removable partial dentures in periodontal abutment teeth in relation to the type of denture support and design of RPD in a five-year worn period. Methods : A total of 64 patients with removable partial dentures (RPDs), participated in this study. It were examined ninety-one RPDs. There were seventy-five RPDs with clasp-retained and sixteenth were RPDs with attachments. There were 28 females and 36 males, aged between 40-64 years, 41 maxillary and 50 mandible RPDs. For each subjects the following data were collected: denture design, denture support, and Kennedy classification. Abutment teeth were assessed for plaque index (PI), calculus index (CI), blending on probing (BOP), probing depth (PD), gingival recession (GR), tooth mobility (TM). Level of significance was set at p<0.05. Results : According to denture support of RPD, BOP, PD, PI, GR, CI and TM-index showed no statistically significant difference. Based on the denture design of RPD’s, BOP, PD, PI, CI, and TM-index proved no statistically significant difference. Except GR-index according to denture design confirmed statistically significant difference in RPD with clasp p<0.01. The higher values of all periodontal parameter as BOP, PD, PI, CI and TM were in patients with RPD’s with claps comparing with RPD’s with attachment. Conclusion : RPD’s with clasp increased level of gingival inflammation in regions covered by the dentures and below the clasp arms in abutment teeth.

A Review: Flexible Removable Partial Dentures

In an era of implants and fixed prosthesis, removable partial dentures are still a treatment of choice for a wide range of patients and clinicians. As every other treatment option, removable prosthesis also has some disadvantages. But with introduction of flexible partial dentures, many of the disadvantages of conventional acrylic and cast partial dentures are taken care of. This article discusses about the material used in fabrication, indications and compares the flexible partial dentures with other removable partial denture options along with design and insertion technique of the flexible removable partial dentures. I. Introduction: The choice between several treatment options for replacing missing teeth is influenced by clinical, dentist- and patient-immanent factors. Replacement of missing teeth is one of the most important needs for patients attending clinics to restore esthetics and/or function. Many treatment modalities are available for replacing missing teeth; removable partial denture, fixed partial denture or dental implant. Each modality is a possible treatment option and has its own advantages and disadvantages. Removable partial dentures became popular many decades ago with the introduction of acrylic polymers and chrome cobalt alloys in dentistry. Many patients choose removable partial dentures due to factors ranging from cost to psychology. Dr. Walter Wright (1937) introduced Polymethyl methacrylate as a denture base material which became the major polymer to be used. Since ages, polymethyl methacrylate (PMMA) has been used to fabricate the dentures. Metal cast / metal frame / metal base dentures are also fabricated to restore the defects. Some of the problems with acrylic are difficult to address, such as insertion in undercut areas, brittleness of methyl methacrylate which leads to fracture, and allergy to methyl methacrylate monomer. In the recent times flexible removable partial dentures have become quite popular. Though search for the ideal option is still on, here is a review of viable option for replacing missing teeth known as flexible dentures.

Mapping of Tooth Loss Profiles and the Variety of Removable Partial Denture Designs Fitted to Patients in a University Dental School Clinic in Trinidad

&lt;p&gt;&lt;strong&gt;Background:&lt;/strong&gt; Clinicians are continually challenged to improve the standard of treatment. Careful measurements and designs, based on knowledge of tooth loss patterns and biomechanical principles, will determine the overall quality of removable prostheses.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Objectives:&lt;/strong&gt; This study maps the pattern of tooth loss in a sample of patients and the most efficient designs employed for their cobalt-chrome removable prosthesis.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Material and Methods:&lt;/strong&gt; Data was collected from gypsum casts, metal castings, and prescriptions sent to dental technicians. The sample included both men (44) and women (109). Information was obtained on their Kennedy classification, number of missing teeth in the maxilla and the mandible, the type of major connector fitted, and when additional indirect retainers with clasps were incorporated into the frame. The significance of the association between pairs of these categorical variables was tested by a Chi Square test.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Results:&lt;/strong&gt; Patients with maxilla loss (82%) had mostly (54%) 6 to 10 missing teeth and were assessed principally (78%) as exhibiting Kennedy Class II or III patterns. Most (77%) of those missing teeth in their mandible (66%) were assessed as either Class I or Class II. The Anterior-Posterior (70%) in the maxilla and the Lingual Bar (74%) in the mandible were the most common fitted connectors. Indirect retainers were used for patients with maxilla (78%) or mandible (96%) tooth loss to provide extra stability.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Conclusion:&lt;/strong&gt; Additional components incorporated in the Cobalt-Chrome frame increased the biomechanical efficiency of the appliance by reducing destructive forces, caused by the torque on the abutment teeth.&lt;/p&gt;

Implant Tooth‐Supported Removable Partial Denture with at Least 15‐Year Long‐Term Follow‐Up

The aim of the present report is to describe the long-term follow-up of cases treated with implant tooth-supported removable partial denture (ITSRPD) after at least 15 years. The study sample comprised 20 consecutively partially edentulous patients treated with ITSRPD. Implants were placed in order to improve unfavorable removable partial denture design resulting from unfavorable teeth distribution and biomechanical considerations, esthetic, or periodontal challenges. All patients were followed up every 6 months for the first 2 years and annually thereafter for at least 15 years. Recall visits for professional cleaning and oral hygiene re-enforcement were scheduled every 3 to 6 mounts. A total of 42 implants were placed in 20 patients and restored with ITSRPD. All implants and prosthetic devices functioned successfully throughout the 15 years of follow-up. Three patients had gone through further implant placement several years after ITSRPD was provided, and a fixed implant-supported restoration was provided on the original and new implants. No implant failure was noted during follow-up, resulting in a rate for implant survival of 100% for the study. Marginal bone loss around implants ranged between 0 and 2 mm (mean 0.64 ± 0.6 mm). During the follow-up period, prosthetic complications were minor and included one rest rupture. All patients answered a questionnaire and were satisfied with the prosthesis. They reported good chewing ability and stability of the prosthetic devices. ITSRPD can be used with predictable long-term results in carefully selected and well-maintained population. Patients should be advised of their role in maintenance, and a comprehensive recall system is mandatory to obtain satisfactory long-term results.

Photoelastic analysis of the influence of residual ridge inclination in conjugated class I mandibular prostheses with different attachment systems

Objectives: The aim of this study was to evaluate the stress distribution in mandibular free-end removable partial dentures (RPD) associated with FPD in the abutment teeth considering different inclinations of the residual ridge: (1) horizontal and (2) distal descending ridges and two designs of free-end RPD with different attachment systems were tested: (1) clasp and (2) system ERA. Methods. Axial loads (100 N) were applied on the teeth of the RPD. The images were recorded and the stress distribution was evaluated through photoelastic fringes. Results. In general, the distal descending ridge presented more photoelastic fringes in the region of the roots of the abutment teeth while the horizontal ridge exhibited higher compression in the base of the prosthesis. In the horizontal ridge, the denture with clasp presented more favourable stress distribution than the denture with the system ERA. In the distal descending ridge, the denture with the system ERA relieved the region of the abutment teeth and overloaded the residual ridge. Conclusion: The horizontal ridge presented more favourable performance; the dentures with clasp exhibited better performance for both ridges evaluated; the denture with the system ERA presented better results in the distal descending ridge.

Removable Partial Denture Design using Milled Surface as a Precision Attachment: An Esthetic Alternative

This case report describes the combined use of fixed partial denture prosthesis (FPD) and removable partial denture prosthesis (RPD) for a patient with partially edentulous arches and few remaining teeth. The RPD was designed such that it would take advantage of the benefits from milled palatal surfaces of the FPD to enhance stability and retention of the RPD and allow maintenance of optimum oral hygiene.

The Effect of Clinical Examination and Kennedy Classification on the Design of Removable Partial Dentures

The success of Removable Partial Dentures (RPD) depends greatly on it's design, (which means acrylic, Cobalt- Chromium [co-ch], and fixed).But unfortunately many dentists delegate their responsibility of RPDS design to the dental technician for one reason or another, this study was done to confirm the effect of kennedy classification and clinical examination on the RPD design, and to identify the changes between design of group (A) dental technician and group (B) the dentists, and to be solved in future.&#x0D; The result show 36% of the cases were modified and changed according to the cases related variables this high and significant number of modification reinforces the position that RPD design should be decided and guided by the dentists. The study conducted the effects of kennedy classification and clinical examination on the RPD design by comparing between designs group of Dental technician without clinical examination and designs marked by the dentists after providing the clinical examination, the change of design was clearly proved that the clinical examination played a very important role in changing the RPD designs.

Pertimbangan laboratoris arah pemasangan rotasi gigitiruan sebagian lepasan rangka logam Laboratory considerations in rotational path of insertion of metal frame removable partial denture

Clinical indications and contraindications for insertion path of removable partial denture (RPD)have been welldiscussed in the literature. However, specific discussion of proper laboratory technique and procedure for dentaltechnician is scarce and limited. This article describes two problems that dental technicians occasionally encounterwhich make the fabrication of rotational insertion path of RPD difficult or impossible. Design modifications by theclinician can eliminate problems faced by technicians in determining the proper path of insertion. Lack of clinicalexperience and/or guidance from the literature related to the insertion path of RPD design may cause laboratoryand clinical problems. The recognition of these potential problems will minimize the laboratory and clinicalproblems

Student perceptions of syndicate learning: tutor‐less group work within an undergraduate dental curriculum

This paper describes the implementation of syndicate learning (tutor-less group working) to teach the basic principles and skills of removable partial denture design within an undergraduate dental curriculum at the University of Glasgow. Student perceptions of syndicate group learning were collected through using questionnaires with Likert scales and through focus group interviews. The majority of students expressed positive views of syndicate learning that focused on the following themes: the added value of the group in terms of learning and in terms of social cohesion; the sense of responsibility to peers that led them to work harder; the autonomy of tutor-less groups that led them to improve their ability to justify their work; and the effectiveness of the syndicate groups in comparison with other learning methods. On the basis of these findings along with reports from students that learning about group roles enhanced their preparation for future work, we argue that syndicate learning can offer some valuable benefits to the undergraduate dental curriculum.

Partial edentulism and removable partial denture design in a dental school population: a survey in Greece

To investigate the pattern of partial edentulism and the most frequent designs of cobalt-chromium removable partial dentures (RPDs), constructed at the Dental School of Athens, Greece. Five hundred and fifty-three patients, between 42 and 81 years old, mostly males, treated by undergraduate dental students, were included. The survey was based on visual evaluation of master casts and work authorisation to dental technicians. Aspects examined were: Kennedy Classification, modification areas, major connectors, clasping, placement of rest seats and indirect retention. Kennedy Class I was the most common encountered in the maxilla (50.5%) and in the mandible (70%). The most frequent major connectors were the lingual bar (92.6%) and the U-shaped palatal strap (54%). The most common clasp was the Roach (69.2%) in Class I and Class II. In Class III and IV, the most common was the occlusally approaching clasp (55% and 70%). The most frequent location of the rest was mesial of abutment teeth. On the average, 39.5% of Class I RPDs and 58.6% of Class II RPDs had indirect retainers. A combination of the two major philosophies of RPD design (biomechanical and hygienic) was evident in the RPDs examined in our study.

Revisiting the Principles of Partial Denture Design

Dentists may find partial denture design difficult. This is often due to lack of educational experience. Removable partial dentures (RPDs) are one-off prosthodontic solutions that require proper assessment, planning and preparation, combined with effective design. This article revisits the principles of RPD design. One in six people in Britain have some form of RPD. Many of these are unworn. For future well-being of patients, improvement in RPD provision is essential.

Evaluation of Senior Brazilian Dental Students About Mouth Preparation and Removable Partial Denture Design

This study aimed to evaluate the knowledge of senior dental students about mouth preparation and removable partial denture (RPD) design. Two hundred sixty-six senior students from eleven dental schools in the State of São Paulo, Brazil, comprised the sample. The subjects examined two partially edentulous casts mounted on a semiadjustable articulator, answered a questionnaire regarding the treatment plan, and drew the RPD design. The casts consisted of Kennedy Class III, modification 1 maxillary arch and Class II mandibular arch. Ninety percent of the students believed that mouth preparation should be performed although no one was able to name all necessary procedures. For the maxillary arch, 12 percent of the denture designs were completely appropriate, 51 percent were partially appropriate, and 37 percent were inappropriate. For the mandibular arch, the results were 3 percent, 40 percent, and 57 percent, respectively.

Partial denture design comparisons between inexperienced and experienced undergraduate students and the teaching staff of a UK dental school

This study aimed to assess the ability of inexperienced and experienced BDS students and teachers of removable partial denture (RPD) design, to prescribe/design RPDs for an identical partial denture case. Second and fourth/fifth year BDS students and experienced teachers of RPD design were selected to provide a treatment plan for a patient requiring RPDs using identical models. The designs produced were compared against a design produced by the authors before the study began. Not one design for the 100 participants matched the author's design. Under 30% of second year students surveyed the models before designing. Only a small percentage of the participants indicated the path of insertion and removal they had chosen and less than half the student groups and only 60% of the staff group provided clear, correct instructions to the technician. Large disagreements existed between the individuals within groups and between individual groups regarding the selection of component parts. There were wide differences in opinion among the undergraduate student groups as to which are the best design options for particular cases. Teachers of RPD design were found to be far from confident and have no consensus of opinion when designing RPDs.

Computer aided design and rapid manufacturing of removable partial denture frameworks

To introduce a method of digital modeling and fabricating removable partial denture (RPD) frameworks using self-developed software for RPD design and rapid manufacturing system. The three-dimensional data of two partially dentate dental casts were obtained using a three-dimensional crossing section scanner. Self-developed software package for RPD design was used to decide the path of insertion and to design different components of RPD frameworks. The components included occlusal rest, clasp, lingual bar, polymeric retention framework and maxillary major connector. The design procedure for the components was as following: first, determine the outline of the component. Second, build the tissue surface of the component using the scanned data within the outline. Third, preset cross section was used to produce the polished surface. Finally, different RPD components were modeled respectively and connected by minor connectors to form an integrated RPD framework. The finished data were imported into a self-developed selective laser melting (SLM) machine and metal frameworks were fabricated directly. RPD frameworks for the two scanned dental casts were modeled with this self-developed program and metal RPD frameworks were successfully fabricated using SLM method. The finished metal frameworks fit well on the plaster models. The self-developed computer aided design and computer aided manufacture (CAD-CAM) system for RPD design and fabrication has completely independent intellectual property rights. It provides a new method of manufacturing metal RPD frameworks.

Sectional removable partial denture design for the treatment of partial mandibulectomy patient: a case report

Surgical removal of tumors in the mandible may result in discontinuity ofbone which may require surgical reconstruction of the defect to provide asuitable tissue foundation for an acceptable prosthesis. Failure ofreconstructive surgery for some mandibulectomy patients often makeprosthetic rehabilitation extremely difficult. Due to financial constraintsan acrylic sectional partial denture was fabricated for a class VImandibular resection patient who had undergone anterior segmentalmandibulectomy with no surgical reconstruction. The case waschallenging and the prosthesis was well tolerated during a 6 monthsfollow-up review.(Afr. J. Biomed. Res. 10: 197 - 201) Keywords: Removable Partial Denture, Design, Mandibulectomy, Case report

Electronic surveying of digital partially dentate casts

To develop a method of surveying the digitalized partially dentate cast in order to accomplish computer aided design (CAD) of removable partial denture (RPD) frameworks. The stone cast of a partially dentate patient was scanned using a three-dimensional laser scanner. Points on the surface of the digitalized cast, termed as a "point cloud", were obtained. The point cloud was then imported into self-developed Tanglong software to sample and uniform. New module of identifying the surveying lines was specially written in Tanglong using C++. A straight line was created in the center of the cloud point. Then the cloud point surrounding the straight line was divided into many parts. Local coordinates were established to indicate the information of angle and distance of every point to the straight line. Surveying lines were produced step by step electronically by identifying the closest and farthest points relative to the straight line and then connected together. Different surveying lines were obtained by adjusting the angle of the straight line. After the surveying lines were decided, the undercut areas could be marked and the depth of undercut was calculated automatically. The blockout of the undercuts could also be achieved by moving the location of the point cloud in undercut area. Survey lines of digitalized partially dentate casts were generated in computer. The undercut area and its depth were identified and the undercut could be blocked out. The shape of survey lines on the digitalized casts was similar to that on the physical casts drawn using traditional method. The new module in Tanglong software was developed specifically for surveying partially dentate casts. It had a user-friendly interface with the easy-to-understand menus. The success of surveying dental casts digitally would make it possible to CAD of RPD frameworks.

Development of an RPD CAD system with finite element stress analysis

The structural design of removable partial dentures (RPDs) is critical for preventing distortion of the prosthesis, protecting abutment teeth and residual ridges as well as for high masticatory performance. The aim of this study was to clarify the feasibility and utility of a computer-aided designing (CAD) system with finite element analysis (FEA) for molar teeth arrangement in unilateral distal extension base RPDs. The shapes of artificial teeth and residual ridge were measured and converted into point group data. Solid models were created from surface-modelled point group data in a 3D surface CAD format. An occlusal rim was created on the residual ridge mucosa and the occlusal rim - residual ridge mucosa model with FEA function was created. Stress distribution on the residual ridge mucosa was compared by changing the loading point. The artificial teeth were then arranged in locations with the lowest amount of stress. After building an artificial teeth - saddle - residual ridge mucosa model, stress distribution in the residual ridge mucosa was re-evaluated by simulating occlusal force. On the occlusal rim - residual ridge mucosa model, stress was reduced when the loading point was located around the buccal shelf where functional cusps of artificial teeth were charted. It was confirmed that stress distribution in the residual ridge mucosa was equalized on the artificial teeth - saddle - residual ridge mucosa model. This system might be clinically useful tool for designing RPDs if FEA-guided designing of retainers and connectors can be added.

An introduction to concept mapping in dental education: the case of partial denture design

The aim of this paper is to present concept mapping as a tool for enhancing clinical dental education and develops the authors' argument for the use of concept mapping presented previously in the pages of this journal. Materials presented are based on data gathered from extensive observation of learning and teaching in a UK dental school, and upon a case study of student learning of removable partial denture design. Using examples developed with students and teachers, critical elements of the approach are illustrated which can be used to support dialogue between the two parties. This approach can be used to develop active teaching strategies and engaged learning approaches that support the development of clinical expertise.

Effect of direct retainer and major connector designs on RPD and abutment tooth movement dynamics

Designs of removable partial dentures are suggested to affect the mobility of abutment teeth and removable partial denture (RPD) during oral functions. This study aimed to examine the effect of direct retainer and major connector designs on RPD dynamics under simulated loading. Six different Kennedy class II maxillary RPDs were fabricated on a maxillary model. These dentures involved 3 different direct retainers (wrought-wire clasp, RPA clasp, and conical crown telescopic retainer) and 2 different major connectors (Co-Cr major connector and heat-cured acrylic resin with a metal strengthener). Using an experimental model with simulated periodontal ligaments and mucosa that were fabricated using silicone impression material, three-dimensional displacements of the RPDs were measured under a simulated 30-N loading with a displacement transducer type M-3. Significant effects of "direct retainer design" on bucco-palatal displacements and "major connector" on mesio-distal displacements were revealed by 2 x 3 two-way analysis of variance of abutment teeth movements (P < 0.001 and P = 0.002, respectively). Additionally, analysis of variance of RPD displacements revealed significant effects of "direct retainer design" on corono-apical displacements and "major connector" on mesio-distal displacements (P = 0.001 and P = 0.028, respectively). Rigid direct retainers and rigid major connectors decrease the movements of both abutment tooth and RPD.

Dual Path: A Concept to Improve the Esthetic Replacement of Missing Anterior Teeth with a Removable Partial Denture

The dual path of insertion concept for removable partial denture (RPD) design may be used in esthetically demanding situations. When compared to conventional RPDs, the main advantage of this design is the minimal use of clasps. This clinical report describes the treatment of a patient with an anterior maxillary edentulous area using a dual path RPD. The diagnostic cast was surveyed to ensure the adequacy of the undercuts on the mesial surfaces of the anterior abutments, where rigid minor connectors were placed. Inverted V-shaped canine cingulum rest seats were prepared to provide resistance to tooth movement during function. The dual path RPD concept allows excellent esthetic results, minimizes tooth preparation, and reduces the tendency toward plaque accumulation in a Kennedy class IV partially edentulous arch.