Alternate framework designs for removable partial dentures

Oral health-related quality of life: acrylic versus flexible partial dentures

Background

Teeth lost are usually replaced by all-acrylic removable partial dentures (RPD) because of its affordability and ease of fabrication. The all-acrylic RPD is said to cause significant periodontal injury and consequently affect the oral health related quality of life (OHRQoL) of denture wearers.

Objective

To determine and compare OHRQoL of all-acrylic and flexible RPD wearers at baseline and after use of dentures.

Design and setting

Study was quasi-experimental using a cross-over design, involving 30 patients with Kennedy class IV and anterior class III arches. Patient recruitment and review were done over an eight-month period in the Prosthetic Unit of a tertiary health facility. OHRQoL was assessed with the oral health impact profile-14 questionnaire. Data were analysed using descriptive and multivariate analysis at asignificant level of p <.05.

Results

Mean age of patients was 33.8 ±10.0 years; at baseline, patient reported occasionally, fairly often or very often for 11(78.6%) OHIP items. However, after using the acrylic and flexible partial dentures, 11(36.6%) patients reported having trouble pronouncing words and 9(30.0%) found it uncomfortable to eat respectively. At baseline, there was a difference in mean OHIP scores with age (p=.02); scores reduced from 12.4 ± 9.8 to 4.8±5.3 (CI= 3.3–12.0, p=.001) after using the all-acrylic denture and 3.8±5.6 (CI= 4.3–13.0, p<.001) with the flexible denture.

Conclusion

There was improvement in the OHRQoL of patients with use of flexible partial dentures. Therefore, thermoplastic materials are possible alternative RPD base materials in patient management.

Funding

None declared

Revisiting the Removable Partial Denture

The partial edentulous population is increasing because of an increasing aging population, increased life expectancy, and individuals retaining more teeth at an older age. Therefore, the need for fixed and removable partial denture (RPD) therapy will remain high and will continue into the future. RPDs provide minimally invasive, cost-effective, timely care, and are preferred to fixed dental prostheses using teeth or implant therapy in many clinical scenarios. This article discusses RPD classification systems to review basic concepts and special framework design considerations, and explores advancements in the field such as implant-assisted RPD, CAD/CAM RPD, and new polymer framework materials.

Form, Function, and Esthetics in Prosthetically Rehabilitated Maxillary Defects

PURPOSE

Patients with maxillofacial defects secondary to the removal of benign and malignant pathologies of midface have a profound impact on quality of life. The aim of this study was to collect and analyze the data pertaining to 4 designs of obturator by assessment of the patient with obturator functioning scale (OFS) MATERIALS AND METHODS:: This retrospective analysis included all the patients who underwent prosthetic rehabilitation of maxillary defects using 4 different types (conventional, cast partial, hollow bulb, and magnet retained) of obturators from 2009 to 2016 with minimum 1 year of follow up. Demographics, number, size, location, type of pathology, postmorbid dentition, and the treatment rendered were recorded. Obturator functioning scale was used to subjectively assess the patient satisfaction.

RESULTS

The mean score on OFS was 5.67 (standard deviation: 1.8). There was a fair and statistical improvement in chewing/eating, speech clarity in public/on phone, swallowing of foods and liquids, pronunciation of words, and social interaction (P < 0.05). The outcome was best in magnet retained followed by cast partial group. The least outcome was in conventional obturator group.

CONCLUSION

Obturators of different designs do play an important role in rehabilitation of maxillary defects with a satisfactory outcome.

Influence of time and different tooth widths on masticatory efficiency and muscular activity in bilateral free-end saddles

PURPOSE

To evaluate the influence of time on masticatory efficiency and muscular activity during mastication of different types of test foods in participants fitted with a lower bilateral free-end saddle removable partial denture (RPD) with wide or narrow teeth.

METHODS

Thirty-six participants consented to undergo evaluation of their masticatory efficiency and recording of their muscular activity, while they wore an RPD with a unified bilateral design, during mastication of different types of test foods. The width of the artificial teeth was changed as follows. Initially (A), the length was adjusted so that the distal end of the mandibular second molars occluded with the distal end of the maxillary second molar (buccolingual width of 7-8 mm). Next (B), the width was decreased to half the maxillary second molars (buccolingual width of only 5 mm). A statistical analysis was performed using SAS software. One-way analysis of variance (ANOVA) was performed followed by Duncan's multiple range tests.

RESULTS

At the 2-month follow-up visit, wider teeth demonstrated greater masticatory efficiency than narrower teeth. However, after 4 months, no significant differences were observed between the two tooth widths. No significant differences in muscular activity were observed.

CONCLUSION

A reduction of the occlusal table width in free-end saddle RPDs resulted in decreased masticatory efficiency 2 months after denture fabrication, but there was no significant difference in muscular activity between narrow and wide teeth. However, after 4 months, the masticatory efficiency of the participants with narrower teeth improved without any changes in muscular activity.

Epidemiological Data and Survival Rate of Removable Partial Dentures

INTRODUCTION

The use of removable partial denture (RPD) is considered as low-cost and common treatment option to rehabilitate edentulous areas.

AIM

This study aimed to investigate the epidemiological data of patients rehabilitated with removable partial denture (RPD) in order to assess treatment survival rate and failures.

MATERIALS AND METHODS

Epidemiological data and medical records of patients treated with RPD between 2007 and 2012 at the RPD discipline of a Brazilian University (Aracatuba Dental School- UNESP) were evaluated as well as dental records of patients who underwent RPD treatments (fabrication or repairs) between 2000 and 2010. Factors such as gender, age, presence of systemic disease, main complaint, edentulous arch, period and cause of denture replacement and the prosthesis characteristics were recorded. The chi-square test was used to assess the differences between the variables and the Kaplan Meyer to assess the survival of the RPDs evaluated.

RESULTS

A total of 324 maxillary RPD and 432 mandibular RPD were fabricated. Most of the patients were women aging 41 to 60-year-old. The number of mandibular RPD Kennedy class I (26%) was statistically higher for the maxillary arch (p<.05). There was no association between main complaint to gender or the presence of systemic disease. The lingual plate was the most common major connector used in the mandible (32%). The main reason for altering the design of replaced RPDs were changes during treatment plan.

CONCLUSION

The number of patients who require RPD is large; most of RPDs are Kennedy Class I. A good treatment plan is very important for achieving a positive treatment outcome, and it is strictly related to the survival rate.

A Survey of Removable Partial Denture (RPD) Retentive Elements in Relation to the Type of Edentulism and Abutment Teeth Found in Commercial Laboratories, Athens, Greece

OBJECTIVE

The aim of this survey was to record removable partial denture (RPD) retentive elements and abutment teeth in partially edentulous patients, identified in commercial laboratories in Athens, Greece.

MATERIAL AND METHODS

628 master casts with the corresponding cast metal frameworks used in the construction of RPDs were evaluated. Casts were photographed to identify the number and position of existing teeth, the partial edentulism class and the retentive elements. Prevalence tables and the x(2) test were used for the statistical analysis of the collected data (α=.05).

RESULTS

There were 276 maxillary (43.9%) and 352 (56.1%) mandibular casts. Maxillary edentulism entailed almost a total absence of right third molars in 96.7% and left third molars 96.0% of casts, with lower rates for the first and second molars. Edentulism in the posterior mandible presented a similar pattern. The most profound findings concerning retentive elements were: 91.9% of the retainers used were clasps and the remaining 8.1% were attachments. Of the clasps used, 48.9% were of the Roach Τ type, a finding more common in Kennedy Class I as compared to other Kennedy Classes (p<0.01). The circumferential clasps accounted for 19.3% of the total clasps used, and it was less frequently presented (8.8%) in Kennedy I Classes (p<0.01).

CONCLUSIONS

Roach clasps were used in the majority of cases whereas RPI clasps and attachments were rarely used.

Removable partial dentures: clinical concepts

This article provides a review of the traditional clinical concepts for the design and fabrication of removable partial dentures (RPDs). Although classic theories and rules for RPD designs have been presented and should be followed, excellent clinical care for partially edentulous patients may also be achieved with computer-aided design/computer-aided manufacturing technology and unique blended designs. These nontraditional RPD designs and fabrication methods provide for improved fit, function, and esthetics by using computer-aided design software, composite resin for contours and morphology of abutment teeth, metal support structures for long edentulous spans and collapsed occlusal vertical dimensions, and flexible, nylon thermoplastic material for metal-supported clasp assemblies.

Surface roughness and internal porosity of partial removable dental prosthesis frameworks fabricated from conventional wax and light-polymerized patterns: a comparative study

STATEMENT OF PROBLEM

Surface roughness and internal porosity are 2 potential risk factors that threaten the biocompatibility and long-term mechanical stability of cast partial removable dental prostheses frameworks.

PURPOSE

The purpose of this study was to investigate the influence of the material, of conventional wax patterns, and the recently introduced light-polymerized patterns on the initial surface roughness and internal porosity of the cobalt-chromium castings of partial removable dental prostheses.

MATERIAL AND METHODS

Twenty-eight identical partial removable dental prosthesis frameworks were fabricated on a cast of a maxillary Kennedy Class III modification 1 partially edentulous patient. Fourteen frameworks were fabricated from each pattern material. The initial surface roughness, Ra (μm), of the resultant castings was measured with a profilometer. Radiographs of the castings were made on dental occlusal films with a dental x-ray unit with the following exposure conditions: tube voltage 70 kV; exposure time 1.0 seconds; tube current 7 mA; and source-film distance 35 cm. The number and size of porosities in the 3 main components (clasp units, major connectors, denture base meshwork) were assessed. Statistical analysis was conducted with the independent sample t test for surface roughness and the Mann Whitney test for internal porosity (α=.05).

RESULTS

The statistical analysis of mean surface roughness and internal porosity revealed no significant difference between the 2 groups.

CONCLUSIONS

The surface roughness and internal porosity of frameworks fabricated from conventional wax and Liwa patterns were comparable, with no significant differences between the 2 pattern materials.

Failures in the rehabilitation treatment with removable partial dentures

BACKGROUND

Despite being functional and having aesthetic benefits, the acceptance of patients regarding the use of removable partial dentures (RPDs) has been low. In part, this is due to the deleterious effects that causes discomfort to the patient. Success depends not only on the care expended by the patient, including daily care and oral hygiene, but also on common goals set by their professional and clinical staff, aiming beyond aesthetics, to incorporate issues of functionality and the well-being of patients.

METHODS AND RESULTS

For rehabilitation treatment with RPDs to reach the desired level of success without damaging the support structure, all the steps (diagnose, cavity preparation, adaptation of the metal structures, functional of distal extension and posterior follow-up) in the rehabilitative treatment should be carefully developed. A literature review was carried out, searching through MEDLINE (PubMed) articles published between 1965 and December 2012 including clinical trials and reviews about the use of RPDs.

CONCLUSIONS

This study describes factors that lead to failures and complications in oral rehabilitation through the use of RPDs and suggests possible solutions.

A systematic review of the clinical performance of tooth-retained and implant-retained double crown prostheses with a follow-up of ≥ 3 years

PURPOSE

The objective of this review was to systematically screen the literature for data related to the survival and complication rates observed with dental or implant double crown abutments and removable prostheses under functional loading for at least 3 years.

MATERIALS AND METHODS

A systematic review of the dental literature from January 1966 to December 2009 was performed in electronic databases (PubMed and Embase) as well as by an extensive hand search to investigate the clinical outcomes of double crown reconstructions.

RESULTS

From the total of 2412 titles retrieved from the search, 65 were selected for full-text review. Subsequently, 17 papers were included for data extraction. An estimation of the cumulative survival and complication rates was not feasible due to the lack of detailed information. Tooth survival rates for telescopic abutment teeth ranged from 82.5% to 96.5% after an observation period of 3.4 to 6 years, and for tooth-supported double crown retained dentures from 66.7% to 98.6% after an observation period of 6 to 10 years. The survival rates of implants were between 97.9% and 100% and for telescopic-retained removable dental prostheses with two mandibular implants, 100% after 3.0 and 10.4 years. The major biological complications affecting the tooth abutments were gingival inflammation, periodontal disease, and caries. The most frequent technical complications were loss of cementation and loss of facings.

CONCLUSIONS

The main findings of this review are: (I) double crown tooth abutments and dentures demonstrated a wide range of survival rates. (II) Implant-supported mandibular overdentures demonstrated a favorable long-term prognosis. (III) A greater need for prosthetic maintenance is required for both tooth-supported and implant-supported reconstructions. (IV) Future areas of research would involve designing appropriate longitudinal studies for comparisons of survival and complication rates of different reconstruction designs.

Esthetic Management of Unilateral Cross Bite with Dento-vestibular Enhancement Prosthetic Appliance

Unilateral crossbite is a commonly encountered condition in clinical practice. The most frequently employed treatment protocol to manage unilateral crossbite is orthodontic correction or orthognathic surgery or combination of both. When the clinical situation less favours both these modalities of management, a transitional prosthetic appliance--dentovestibular enhancement prosthetic appliance- can be effectively used to manage this condition.

Prevalence of removable partial dentures users treated at the Aracatuba Dental School-UNESP

OBJECTIVES

The aim of this study was to evaluate the frequency of removable partial dentures (RPD) at the Aracatuba Dental School.

METHODS

The study was conducted by analysing 412 clinical history of patients attended at the RPD clinics in the period from 2000 to 2007.

RESULTS

412 charts were analysed: 148 (35.9%) men and 264 (64.1%) women. The mean age was 53.8 years (men) and 52.4 years (women). A total of 556 dentures were made; of these, 233 (41.90%) were maxillary and 323 (58.09%) were mandibular dentures. The most frequent Kennedy classification found was Class III (maxilla) and Class I (mandible). In the maxilla, 55% (126) of the major connectors were of the anterior-posterior palatal bar, while in the mandible, 64% (202) were the lingual bar. As regards the claps, 401 were circumferential and 318 were bar claps.

CONCLUSION

The mean age of the patients was 52.9 years with higher prevalence of female patients; the most frequent Kennedy's classification was Class I in mandible and Class III in maxilla; the most common major connector was anterior-posterior palatal bar for maxilla and lingual bar for mandible; the circumferential clasps were the most common retainer used in both jaws.

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

OBJECTIVES

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.

METHODS AND MATERIALS

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.

RESULTS

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.

CONCLUSION

A combination of the two major philosophies of RPD design (biomechanical and hygienic) was evident in the RPDs examined in our study.

Functional evaluation of oral rehabilitation with removable partial dentures after five years

Most removable partial denture (RPD) wearers are satisfied with their prostheses, but the factors that influence satisfaction and acceptance are still not determined.

OBJECTIVE

This study explored technical, biological, and satisfaction variables for the functioning of RPDs after five years, and compared the evaluation by the patient and by the clinician.

MATERIAL AND METHODS

Fifty adults (39 females, 11 males) were re-examined after five years of RPD service. Data were collected through clinical examination and a structured questionnaire to record the conditions of supporting soft tissues, prosthesis acceptance and technical characteristics, mastication, esthetics, comfort, hygiene, and need for professional intervention. Data were analyzed by descriptive statistics and Spearman correlation.

RESULTS

More than 50% of patients classified their RPDs as excellent regarding retention, mastication, esthetics, comfort, and hygiene. In the professional evaluation, retention and stability were considered excellent in more than 66% of cases, and hygiene of teeth and prostheses was considered good in 52% and 46%, respectively. The metallic framework and acrylic base were considered adapted in 92% of cases. Prosthesis acceptance was associated with retention, mastication, esthetics, hygiene, and comfort evaluated by the patient, and with retention, stability, and condition of the framework evaluated by the clinician. Retention and mastication/comfort evaluated by the patient had moderate positive correlation with retention and stability measured by the clinician. There was no association of hygiene evaluation by the patient and by the clinician.

CONCLUSIONS

After five years, the oral rehabilitation with RPDs was satisfactory for most cases. There was correspondence between retention/retention and mastication-comfort/stability variables evaluated by the patient and by the clinician. Oral and prosthesis hygiene were not related.

The computer-aided design and rapid prototyping fabrication of removable partial denture frameworks

This study explores the application of computer-aided design and manufacture (CAD/CAM) to the process of electronically surveying a scanned dental cast as a prior stage to producing a sacrificial pattern for a removable partial denture (RPD) metal alloy framework. These are designed to retain artificial replacement teeth in the oral cavity. A cast produced from an impression of a patient's mouth was digitally scanned and the data converted to a three-dimensional computer file that could be read by the computer-aided design (CAD) software. Analysis and preparation were carried out in the digital environment according to established dental principles. The CAD software was then used to design the framework and generate a standard triangulation language (STL) file in preparation for its manufacture using rapid prototyping (RP) methods. Several RP methods were subsequently used to produce sacrificial patterns, which were then cast in a chromium-cobalt alloy using conventional methods and assessed for accuracy of fit.

This work demonstrates that CAD/CAM techniques can be used for electronic dental cast analysis, preparation, and design of RPD frameworks. It also demonstrates that RP-produced patterns may be successfully cast using conventional methods and that the resulting frameworks can provide a satisfactory fit.

A technique for fabricating patterns for removable partial denture frameworks using digitized casts and electronic surveying

Although computer-aided design and manufacture techniques have shown some promising applications in the fabrication of crowns, inlays, and maxillofacial and oral surgery, the field of removable prosthodontics has not embraced these technologies so far. This article describes the development and investigation of computer-aided techniques that may eventually enable prosthodontic procedures such as surveying and the production of sacrificial patterns to be performed digitally. A 3-dimensional computer model of a conventional cast from a patient was obtained using an optical surface capture device (a scanner). The shape of a number of components of a removable partial denture framework was modeled on the 3-dimensional scan electronically, using computer-aided design software. A physical plastic shape of the components was produced using a Rapid Prototyping machine and used as a sacrificial pattern. Techniques to allow digital cast surveying before the production of sacrificial patterns were also developed. The results show that digital dental surveying and machine-produced sacrificial patterns can be accomplished. This article forms a basis for further developments leading to a fully integrated approach to the computer-aided design and fabrication of removable partial denture frameworks.

A comparison of patient's satisfaction between complete and partial removable denture wearers

OBJECTIVES

The aim of this study was to compare satisfaction between complete denture (CD) and Kennedy Class I removable partial denture (RPD) wearers.

MATERIALS AND METHODS

A total of 156 CD and 112 RPD wearers took a part in this study. From the primary group of the examined patients, only those whose RPDs and CDs were assessed as excellent or very good by the dentist, took a part in this study. Patients graded satisfaction of their dentures by using an analogue scale from 1 to 5 (1=unsatisfactory; 5=excellent).

RESULTS

Both CD and RPD wearers were mostly satisfied with their dentures (the distribution of the scores of the patients' assessments was skewed towards the highest scores; more than half of the patients scored all the examined variables to the best score category). Complete Denture wearers were significantly more satisfied with chewing, speech and retention of maxillary denture than RPD wearers (P<0.05). Removable partial denture wearers were significantly more satisfied with the retention and the comfort of wearing mandibular denture (P<0.05). There was no significant difference between CD and RPD wearers for general satisfaction with their dentures, aesthetics and comfort of wearing maxillary denture (P>0.05; N.S.).

CONCLUSIONS

A majority of CD and RPD wearers were satisfied with the dentures. CD wearers were more satisfied with speech, chewing and retention of maxillary denture, while RPD wearers were more satisfied with the retention and the comfort of wearing mandibular denture. Different groups of denture wearers have to make significant, but different adjustments to wear their dentures successfully.

A survey of treatment outcomes with removable partial dentures

The patient's satisfaction with removable partial denture (RPD) therapy has become an increasingly important factor in prosthetic treatment. This study examined patients' satisfaction with RPDs in relation to some socio-economic variables, patients' habits of wearing and cleaning RPDs, comfort of wearing RPDs and different RPDs characteristics. A questionnaire was devised for the purpose. Two hundred and five patients were required to assess satisfaction with RPDs. They graded RPDs, depending on the level of satisfaction, on scale ranging from 1 to 5. A dentist determined Kennedy classification, material and denture support, denture base shape, number of missing teeth and evaluated denture construction. Majority of the patients were satisfied with the prosthesis. The patients of a higher education level gave lower grades (P < 0.05) to aesthetics of maxillary RPDs. Almost half of the patients were wearing RPDs during the day. Most of the patients cleaned RPDs three times a day. A significant difference was found between the patients' grades for comfort of wearing mandibular RPDs and number of missing teeth and between hygiene of mandibular RPDs and habits of cleaning them. Majority of the patients treated with RPDs were satisfied with the prosthesis. Dissatisfaction was related to mastication, esthetics, number of missing teeth and maintenance of oral hygiene.