Tooth preparation for rest seats for cobalt-chromium removable partial dentures completed by general dental practitioners

Abstract

The aim of this project was to examine tooth preparations made by general dental practitioners (GDPs) for occlusal and cingulum rest seats for cobalt-chromium removable partial dentures (RPDs). Master casts and prescribed denture designs for cobalt-chromium RPDs produced by a commercial dental laboratory from impressions made by 45 GDPs across Wales were evaluated over a period of 5 months. Rest seats and associated interocclusal clearances were assessed using pre-determined criteria. A total of 68 casts were examined. Of these, 33 did not have rest seats included in their prescription. Of the remaining 35 casts, 81 rests had been prescribed of which only 24 (30%) had signs of tooth preparations for these rest seats. Using pre-determined criteria, 60% of rest seats were under-prepared in the mesio-distal plane and 30% were over-prepared in the bucco-lingual plane. In 17 cases where natural teeth opposed the rest seat, the mean interocclusal clearance was 1·5 mm (range 0·6-3·5 mm) with 6 of the 17 rests (35%) being less than the recommended thickness. In total, 18 of the 24 rests prepared did not meet the criteria, and 11 of the 21 rests prescribed had no obvious preparation and insufficient occlusal clearance. Where prescribed, the majority of rests did not meet the identified criteria. The rest seat preparations varied greatly in all planes including the interocclusal clearance. Further emphasis should be given to aspects of denture design in undergraduate and continuing education programmes for dentists.

Designing cobalt chromium removable partial dentures for patients with shortened dental arches - a pilot survey

“…Recently, Rice et al. (39) reported that when rests were prescribed, only 30% of the examined master casts for cobalt chromium RPDs had signs of rest seats preparation. Basker et al.…”

“…Schwarz and Barsby (38) found that 56% of UK dentists never or rarely prepared rest seats. Recently, Rice et al (39) reported that when rests were prescribed, only 30% of the examined master casts for cobalt chromium RPDs had signs of rest seats preparation. Basker et al (24) indicated that evidence of rest seat preparation was identified in 21% of cases.…”

Variations in teaching of removable partial dentures in Spanish dental schools

“…There is much to be gained in terms of developing student confidence in this important area prior to treating patients. Evidence from general dental practice suggests that dentists do not always complete optimum rest seat preparations prior to making RPDs, resulting in either inferior quality prostheses or adversely affecting the occlusion of patients receiving this treatment (25). In seven public (64%) and two private (50%) dental schools, undergraduate students did not routinely use a surveyor when designing their removable partial dentures.…”

Longitudinal Improvement in Periodontal Parameters between RPD Abutment Teeth with Direct and Indirect Retainers, after Periodontal Therapy

“…As such, treatment strategies that consider signs and symptoms during the periodontal clinical examination of patients are important to provide adequate prosthetic planning and ensure the success of the treatment. Additionally, patient examination and prosthesis preparation should be executed correctly . The principles of treatment planning should be applied based on an individual assessment of the patient .…”

“…Additionally, patient examination and prosthesis preparation should be executed correctly. 28 The principles of treatment planning should be applied based on an individual assessment of the patient. 29 Thus, oral cavity preparation is essential to the success of an RPD after its installation.…”