Gingival Response to Various Types of Removable Partial Dentures

Abstract

ONE OF THE MAIN OBJECTIVES of prosthetic dentistry is to preserve the remaining periodontal tissues in a state of health. At the same time, periodontal health is necessary for the proper functioning of removable partial denture restorations. Thus, the prosthetic and periodontal treatment are not only interrelated but also interdependent.Various designs and several denture base materials are currently used in removable partial dentures. However, opinions vary regarding the effect of these dentures on the periodontal tissues of the remaining natural dentition. Some feel that the partial denture should cover the gingival margin, with or without relief; others advocate leaving the marginal gingiva completely uncovered in order to preserve and maintain the healthy status of the gingiva. The present investigation was conducted to seek a solution to such a prosthetic-periodontal problem. MATERIALS AND METHODSSixty-eight patients (36 males and 32 females) were selected from the prosthodontic clinic, Faculty of Dentistry, Cairo University, on the basis of having two or more maxillary missing teeth. Their ages varied from 17 to 49 years. All patients were free of any apparent systemic disease. A medical and dental history, a dental and periodontal examination, periapical roentgenographs and maxillary and mandibular study casts were completed for each patient. Posterior free-end removable partial denture patients were not included.After the clinical examination and the survey of the study casts, a treatment plan was developed for construction of a removable partial denture. Appropriate procedures were carried out including oral prophylaxis, instructions in oral physiotherapy and preparation of occlusal rests. Impressions for the master casts were made one week after the mouth preparation procedures.Twenty-eight metallic (cobalt-chromium) and 40 nonmetallic (methylmethacrylate) partial denture bases were randomly constructed. In both the metallic and nonmetallic dentures the direct retainers used were cast metal clasps, with occlusal rests, bracing and retentive arms.In designing the denture, whether metallic or nonmetallic, three types of denture-gingiva relationship were outlined on the study casts according to the number and distribution of the remaining teeth. The three types treated on a random basis were:1. The palatal gingival margin of two or three teeth was kept covered by the palatal plate without doing any intentional relief on the study cast.2. The palatal gingival margin of another group of two or three teeth was covered completely by the palatal plate with a relief. Wax was used to block out gingival crevices, over which two thicknesses of 0.002 inch tinfoil were adapted and cemented on the master cast for a distance of 3-4 mm. from the gingival margin to secure the intended relief.3. The palatal gingival margin of a third group of two or three teeth was kept far away from the palatal plate. The distance between the gingival margin and the plate ranged between 5 and 6 mm.Either two or all three of the differen...

Cobalt Chromium Denture Designs In General Practice

“…(Table 4) When designing removable partial denture, it has been recommended that gingival margins should remain uncovered and that the distance from the gingival margin to the denture base should be at least 3 mm. This is to avoid trauma from the denture base (21)(22)(23).…”

Removable Partial Denture Designing: Variation of Hard and Soft Tissue Anatomy and Maxillary Major Connector Selection

“…The less amount of tissue that an RDP covers, the greater the advantages in hygiene and health of the soft tissues. The perceived need for structural rigidity must be balanced with the advantages smaller connectors provide to the patient comfort and tissue health [53,54]. A flexible major connector causes an unequal distribution of forces with changes in their intensity, thus causing damage to the supporting structures [55,56].…”

“…The gingivae are the most susceptible to injury from the stress induced by a removable prosthesis. Even minor contacts seem to promote an unfavorable reaction in these areas [53,55,56]. Inflammation in the areas of contacts made by the MC specially plated one, which must cross the gingiva is soon followed by edema.…”

“…Without adequate occlusal rest stops, there can be gingival impingement in these crossing areas [60]. The gingival response to various types of RPDs depict that the denture made with no gingival relief had the most associated pathology [53]. At the time of construction, a slight relief should be made at each gingival crossing.…”

“…At the time of construction, a slight relief should be made at each gingival crossing. Particular care should be given to the matter of rounding the edges of the prosthesis, which are adjacent to or cross the gingivae [53]. The second fundamental requirement of a MC is that it must not permit impingement upon the free gingival margins of the remaining teeth.…”