Title Limited Evidence to Support The Concept That The I-Bar Clasp Partial Removable Dental Prosthesis (PRDP) For Kennedy Class I and II Conditions Is Clinically More Effective Than The Circumferential Clasp Design
Clinical Question Is there a clinically significant difference in the outcome of the Kennedy Class I or II PRDP using an I-bar clasp design as compared to a circumferential clasp design?
Clinical Bottom Line There is little evidence to support the concept that the I-bar design for Kennedy Class I and II PRDPs is more effective than the circumferential clasp design. (See Comments on the CAT below)
Best Evidence  
PubMed ID Author / Year Patient Group Study type
(level of evidence)
7965900Kapur/1994N=134 PRDP Kennedy Class I and II patientsRandomized Controlled Trial
Key resultsPatients were randomly assigned to either the I-bar design group or the circumferential clasp design. Terminal abutments on the distal extension side of the Kennedy Class II and distal abutments of the Kennedy Class I PRDP were designed with one of the following: 1) I-bar design with mesial rest, distal guide plane, and facial bar clasp, or 2) circumferential clasp design with distal rest, distal guide plane, and facial circumferential clasp. Statistically the 5-year I-bar success rate of 76.6% did not differ significantly from the 71.3% circumferential clasp (p>0.05). No significant differences were noted in the nine parameters of periodontal health evaluated, maintenance required, and effects on abutment teeth.
374712Tebrock/1979N=5 Mandibular PRDP Kennedy Class I patientsClinical Trial
Key results5 patients each had three mandibular Kennedy Class I PRDPs fabricated with either an I-bar as described in the previous study, a circumferential clasp as described, or a wrought wire retentive clasp with a distal rest and a lingual bracing arm. Each patient wore each of the three PRDPs for one month. Mobility of abutment teeth was evaluated at one week intervals. No significant differences in tooth mobility were observed for any design (p>0.05).
Evidence Search (("denture, partial, removable"[MeSH Terms] OR ("denture"[All Fields] AND "partial"[All Fields] AND "removable"[All Fields]) OR "removable partial denture"[All Fields] OR ("removable"[All Fields] AND "partial"[All Fields] AND "denture"[All Fields])) AND design[All Fields]) AND Randomized Controlled Trial[ptyp]
Comments on
The Evidence
Very little evidence that addresses the clinical question is available. Only one long term RCT that specifically compared the efficacy of PRDP clasp configuration was found. In both studies specific details on clasp configuration were lacking. For example, length of distal guide plates was not described. The I-bar design may not have conformed to the original configuration as described by Kratochvil (JPD 1963). The second study cited had a limited number of patients and the observation period was only one month for each design. Similar conclusions were derived; no significant difference in designs was noted.
Applicability The evidence available does not demonstrate a clinical advantage to using an I-bar PRDP design compared to a circumferential clasp. How well the particular design is executed may be more critical to clinical success than the design chosen. A design that best meets the particular needs of the patient should be selected. For example, if there is opposing occlusion in the mesio-occlusal surface of a distal abutment, a design with a distal rest should be considered.
Specialty (General Dentistry) (Prosthodontics) (Restorative Dentistry)
Keywords Removable partial denture design
ID# 2472
Date of submission 03/27/2013
E-mail walter.daniels@ucdenver.edu
Author Walter C. Daniels, DMD
Co-author(s) e-mail
Faculty mentor
Faculty mentor e-mail
Basic Science Rationale
(Mechanisms that may account for and/or explain the clinical question, i.e. is the answer to the clinical question consistent with basic biological, physical and/or behavioral science principles, laws and research?)
None available
Comments and Evidence-Based Updates on the CAT
by Benjamin Pass, Aimee Villamayor (San Antonio, TX) on 08/10/2013
I completed a PubMed search in August 2013. In 1997, Kapur conducted a follow-up study comparing masticatory outcomes with between I-bar and circumferential removable partial denture (RPD) designs (PMID: 9237141 ). The 1994 Kapur study measured five-year success rates and periodontal health with unremarkable differences. The recent study found no significant difference in masticatory function via a randomized control trial, providing additional insight regarding the methodology of RPD design.