Influence of rigidity of retainers on dynamic behavior of implant-supported removable partial dentures

International Journal of Implant Dentistry

Masayasu Saito¹  Atsuro Yokoyama¹  Naomichi Murashima²  Yoshiyuki Takayama³  Toshifumi Nogawa⁴ 

[1] Oral Functional Prosthodontics, Division of Oral Functional Science, Facility of Dental Medicine, Hokkaido University, Sapporo, Japan;Oral Functional Prosthodontics, Division of Oral Functional Science, Graduate School of Dental Medicine, Hokkaido University, Sapporo, Japan;Oral Rehabilitation, Hokkaido University Hospital, Sapporo, Japan;Preventive Dentistry, Hokkaido University Hospital, Sapporo, Japan;

关键词: Implant-supported partial dentures;    Removable partial dentures;    Direct retainers;    Dynamic behavior;    Rigidity of connection;   

DOI  :  10.1186/s40729-020-00260-4

来源: Springer

【 摘 要 】

BackgroundImplant-supported removable partial dentures (ISRPDs) are an effective treatment for partially edentulous patients. ISRPDs improve patients’ satisfaction and oral function to a greater extent than RPDs by improving denture stability and enhancing support. However, the effect of a type of direct retainer on displacement of the abutment teeth and dentures in ISRPDs remains unclear. Therefore, we made a resin mandibular model of unilateral mandibular distal-extension partial edentulism for mechanical simulation and compared the dynamic behavior of the abutment teeth and the denture base among different tooth-borne retainers with various rigidities for RPDs and ISRPDs.MethodsA resin mandibular model for mechanical simulation that had unilateral mandibular distal-extension edentulism and was missing the first molar, second molar, first premolar, and second premolar, and a denture fabricated from the patient’s computed tomography images were used. Three types of direct retainers with different connecting rigidities were evaluated. The vertical displacement of the denture base and buccal and lingual sides and the mesial displacement of the abutment teeth were measured.ResultsRegardless of the rigidity of the direct retainers and loading positions, the displacement of the denture bases in the ISRPDs was significantly smaller than that in the RPDs (P < 0.001). There was no significant difference in vertical displacement of the denture bases among direct retainers with various connecting rigidities in the ISRPDs. Conversely, horizontal displacement of the abutment teeth in both the RPDs and ISRPDs tended to be larger with the cone crown telescope, which has high rigidity, than with the cast cingulum rest and wire clasp, which have much lower rigidities.ConclusionOur results suggested that cast cingulum rest and wire clasps as direct retainers are appropriate ISRPDs to minimize denture movement and suppress displacement of the remaining teeth in patients with unilateral mandibular distal-extension partial edentulism.

【 授权许可】

CC BY