Survey of partial removable dental prosthesis (partial RDP) types in a distinct patient population.

STATEMENT OF PROBLEM: Current demographic information on the number and types of removable partial dentures is lacking in the prosthodontic literature. PURPOSE: This study was designed to investigate patterns of tooth loss in patients receiving removable partial dentures (RPDs) in eastern Wisconsin. MATERIAL AND METHODS: Digital images (1502) of casts at 5 dental laboratories in eastern Wisconsin were collected. Any prescription requesting fabrication of a removable partial denture was photographed twice. The first photograph was made immediately upon arrival at the laboratory, while the second photograph was made immediately before being returned to the prescribing dentist for the first time. A calibrated investigator analyzed all the photographs for Kennedy Classification, type of RPD, major connector, and other details. Data were analyzed with descriptive statistics. Fisher's exact test was used to confirm repeatability. RESULTS: Kennedy Class I was the most common RPD with a frequency of 38.4%. More than 40% of prescriptions had no design input from the dentist. One in 3 RPDs used acrylic resin or flexible frameworks. One in 5 RPDs had no rests. The horseshoe major connector was the most common maxillary major connector, while the lingual plate was the most common in the mandible. CONCLUSIONS: RPDs remain a common prosthodontic treatment in this region. Non-metal RPD frameworks are a common treatment type and rarely include rests. These data indicate a changing partially edentulous patient population and a variable commitment to standard levels of prosthodontic care.

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.

Terminology for implant prostheses.

The use of systematic terminology for implant prostheses can simplify communication within the scientific community. However, a review of the current literature demonstrates the lack of uniformity in this field. It is the purpose of this manuscript to suggest uniform terminology based on conventional prosthodontic terms that will simplify communication in the profession.

Design principles for cantilevered resin-bonded fixed partial dentures.

Recent clinical studies show 2-unit cantilevered resin-bonded fixed partial dentures to be as retentive or more retentive than their fixed-fixed counterparts. The fact that the 2-unit prosthesis is successful adds value to the clinical use of resin-bonded fixed partial dentures because the single-abutment prosthesis is even simpler and more cost effective than fixed-fixed designs. However, there is no evidence-based information relating to design principles for abutment preparation and framework design for the single-abutment, single-retainer prosthesis. The aim of this report is to suggest principles of design for the 2-unit cantilevered fixed partial denture, based on information gained from studies on fixed-fixed designs.

Further aspects of design for distal extension removable partial dentures based on the Kennedy classification.

A supplement to the Kennedy classification of partially edentulous arches for restoration with removable partial dentures has been suggested. Factors affecting denture design relating to the position of the abutment teeth, the symmetry of the edentulous distal extensions, the arch form and the cross-sectional shape of the residual ridges have been discussed and classified. An understanding of the movement of the denture bases in relation to the influence of these factors makes for a rational approach to removable partial denture design and the treatment of complications observed clinically in removable partial denture wearers.

The effect of storage time of removable partial denture wax pattern on the accuracy of fit of the cast framework.

STATEMENT OF PROBLEM: Situations may arise in dental laboratories that could result in a time lapse between preparing the wax pattern of the removable partial denture framework and its casting into the cobalt-chromium alloy. PURPOSE: This study investigated the effect of storage time of the wax pattern before casting and the influence of the palatal major connector design on the accuracy of its fit on the master casts. MATERIAL AND METHODS: Forty-two frameworks were prepared with two designs of major connectors, which were divided into three subgroups according to the storage time of the wax patterns: 24 hours, 1 week, and 1 month. Discrepancies in the fit of the connectors to their respective casts were measured at specific locations for both connector designs. RESULTS: In both framework design groups, there was a significant deterioration in fit (p < 0.0005) of the major connectors with the increase in storage time of their wax patterns on their respective refractory casts. Gap discrepancies were more pronounced towards the center of the palate. CONCLUSIONS: The greatest discrepancies appeared at the middle sections of the connectors more than at the lateral section (p < 0.0005). Furthermore, frameworks with modified palatal plate major connectors exhibited greater inaccuracies in their fit than those with the anterior posterior palatal strap design, as evidenced by the increase in mean gap discrepancies under the palatal plate design (p < 0.0005).

Frecuencia de los tipos maxilares parcialmente edéntulos y diseños indicados para su tratamiento con protesís parciales removibles en la UCV / Incidence of classes of maxillar partially edentulous and indicate designs for treatment with removable partial dentures in UCV

En el presente trabajo se estudia la frecuencia con que se presentan los maxilares parcialmente edéntulos, según la clasificación de Kennedy y el diseño empleado para su tratamiento. Para tal fin se tomaron los casos de Prótesis Parciales Removibles elaborados en el pregrado de la Facultad de Odontología de la UCV, en el período abril-junio de 1992. En este lapso se presentaron 290 casos, en los cuales la Clase I inferior y la Clase III superior resultaron los tipos de arcadas parcialmente edéntulas más frecuentes, encontrándose una notable coincidencia con estudios realizados por otros autores. En cuanto a los diseños utilizados para el tratamiento de dichos casos, se concluyó que la frecuencia con que estos se presentan se corresponde con la frecuencia con que ocurren situaciones clínicas específicas. Existen diseños que son indicados frecuentemente a pesar de que en la literatura se evidencia que su uso está restringido a situaciones muy específicas, tal es el caso del gancho de acción posterior y el mayor en forma de herradura o galápago. La ausencia de otras alternativas de diseño se le acredita a criterios académicos y/o limitaciones de los laboratorios dentales de nuestro medio