A randomized clinical trial on the comparison of clinical performance and patient satisfaction of partial dentures made from acetal resin and cast cobalt chromium

The rise in the number of partially edentulous patients, has resulted in a greater need for prosthetic rehabilitations. While there are several available options for fixed prosthetic treatments, such as FPDs and implants, certain clinical situations necessitate the use of removable partial dentures, which still present benefits when compared to the fixed treatment options. Additionally, the escalating expenses associated with fixed prosthesis have contributed to an increased demand for partial dentures.

Edentulism due to trauma, caries or periodontal disease affects the masticatory function and phonetics of the patient. Along with these, another factor to be concerned in the current era is aesthetics. In aesthetic zones, the conventional or commonly used metal clasps and dentures pose disadvantages. In addition, adverse tissue reactions can occur due to the release of toxic ions from metal cast partial dentures. (Saad, 2021)

To overcome all the disadvantages of conventional metal partial dentures, thermoplastic resin has been recently introduced. One of which is polyoxymethylene (acetal) resin; advantages of which include superior aesthetics, patient comfort, high fatigue strength, low

bacterial adhesion, minimal or no monomer and lower water sorption. (Abdelnabi, 2018)

Nevertheless, despite its benefits, acetal resin does have certain limitations. One of the limitations is that the retentive force of the clasps made from acetal resin is reduced when compared to cobalt chromium. This is primarily due to its low modulus of elasticity.

Additionally, the greater flexibility of acetal resin necessitates a bulkier design to compensate retention which creates pathway for plaque accumulation (Smitha, 2012). Despite reduced retentive force of the clasps made from acetal resin, it exhibits less or no deformation during prolonged use when compared with conventional cobalt-chromium clasps. (Taleb, 2013)

Literatures supporting clinical performance and patient satisfaction of acetal resin dentures specifically in Kennedy’s class 1 and 2 situations with long term follow up is scarce. Though various invitro studies on the stress distribution, deformation, retentive ability is available, there are very less clinical studies on the efficacy of acetal resin partial dentures.

Furthermore, there is a lack of literature on randomized clinical trials conducted on this subject.

Aim of the study: To evaluate and compare the clinical performance and patient satisfaction of acetal resin and cobalt-chromium partial dentures over a period of 6 months.

Objectives of the study:

1. To evaluate the clinical performance (periodontal health including pocket depth, clinical attachment loss, gingival index, tooth mobility and plaque index; radiographic evaluation of abutment teeth) for partial dentures made from acetal resin and

cobalt-chromium at baseline and at 6 months post insertion.

2. To evaluate the patient satisfaction for partial dentures made from acetal resin and cobalt-chromium at baseline and at 6 months post insertion.

3. To compare the clinical performance and patient satisfaction for partial dentures made from acetal resin and cobalt-chromium at baseline and at 6 months post insertion.