Patients' Satisfaction and Clinical Investigation of Removable Partial Denture Anchorage With Extracoronal Adhesive Attachments in Comparison With Clasp-retained Partial Dentures

NCT07160660 | Enrolling By Invitation DMC

• 1 other identifier: PSCI2025
• Study Type: observational
• Target: 250
• Locations: 1 country
• Sites: 1

Brief Summary

Removable partial dentures (RPD) are a well-established treatment option for the prosthetic rehabilitation of partially edentulous patients. They are retained at the remaining natural teeth by clasps to provide functional stability. As an alternative to clasps extacoronal adhesive attachments are fixed to the abutment teeth using adhesive cementation techniques. These adhesive attachments improve retention and stability of the prostheses and are indicated when the patient requires a non-visible retention element and healthy coronal tooth structure is available as a prerequisite. In clinical practice, extracoronal adhesive attachments offer a minimally invasive and aesthetic anchoring alternative of removable dental prostheses associated with higher costs compared to a common clasp retention. As a result, adhesive attachments are relatively rarely used and are technically sensitive both in the clinical realisation and in terms of the dental technology. Hence, limited scientific data are available regarding their long-term clinical behaviour, but no data is available about patients' satisfaction with such extracoronal adhesive attachments. This research project aims to investigate patients' satisfaction with extracoronal adhesive attachments (group A) of removable dental prostheses in comparison to clasps (group B), and to investigate the short- and long-term clinical performance of both treatment options. This is a non-interventional observational study. Only routine clinical examinations are performed. No additional risks or burdens arise for participants. All measures fall under minimal risk A according to ClinO, Art. 61. Overall risk: Minimal. No invasive procedures or biological sampling. Ethical and legal standards are fully met. Sex and gender dimensions are not relevant to the topic of the study as the population is determined by patients treated since 2001 and cannot be influenced by the study design.

Conditions

Clasp-retained Partial Dentures; Patients Satisfaction With Removable Dental Prostheses; Extracoronal Adhesive Attachment

Outcome Measures

Primary Outcomes (1)

• Patients' satisfaction with extracoronal adhesive attachments (group A) compared to conventional clasp-retained prostheses (group B) on a visual analogue scale (VAS)

  The primary objective of this study is to assess patients' satisfaction with extracoronal adhesive attachments (group A) compared to conventional clasp-retained prostheses (group B) on a visual analogue scale (VAS). The scale ranges from 0 - 100. A lower score means a worse outcome (satisfaction low) and a higher score a better outcome (satisfaction high). The participants will be instructed and asked to mark a point on the scale according to their satisfaction with the extracoronal adhesive attachment or the clasp-retained prostheses.

  From 2001 to present (RDP with retention element has to be in place for at least 6 months)

Secondary Outcomes (2)

• Occurrence of biological complications associated with the use of extracoronal adhesive attachments and conventional clasps

  From 2001 to present (RDP with retention element has to be in place for at least 6 months)

• Occurrence of technical complications associated with the use of extracoronal adhesive attachments and conventional clasps

  From 2001 to present (RDP with retention element has to be in place for at least 6 months)

Study Arms (2)

Patients with extracoronal adhesive attachments as retentive elements of RPD (group A)

RDP = removable dental prostheses

Other: Patients' satisfaction and clinical investigation of removable partial denture anchorage with extracoronal adhesive attachments

Patients with clasps as retentive elements of RPD (group B)

RDP = removable dental prostheses

Other: Patients' satisfaction and clinical investigation of removable partial denture anchorage with conventional clasps

Interventions

Patients' satisfaction and clinical investigation of removable partial denture anchorage with extracoronal adhesive attachments OTHER

* Completion of a questionnaire by the participant, including patient satisfaction on VAS (visual analogue scale) and prostheses usability, clinical examination of the remaining dentition, the abutment teeth of the extracoronal adhesive attachment and the RPD. * Evaluation of the attachment's condition, retention, and any signs of biological or technical complications. * Collection of relevant medical and dental history from patients' records (consent provided).

Patients with extracoronal adhesive attachments as retentive elements of RPD (group A)

Patients' satisfaction and clinical investigation of removable partial denture anchorage with conventional clasps OTHER

* Completion of a questionnaire by the participant, including patient satisfaction on VAS (visual analogue scale) and prostheses usability, clinical examination of the remaining dentition, the abutment teeth of the clasps and the RPD. * Evaluation of the clasps' condition, retention, and any signs of biological or technical complications. * Collection of relevant medical and dental history from patients' records (consent provided).

Patients with clasps as retentive elements of RPD (group B)

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)
• Sampling Method: Non-Probability Sample

Study Population

This is a retrospective study including all available patients who received an extracoronal adhesive attachment at the University Center for Dental Medicine Basel (UZB) between 2001 and 2025 and a comparable group (same observation group, age and distribution of abutment teeth) with a comparable sample size who received a clasp-retained RPD. Eligible cases will be identified using the relevant billing code entered into the internal billing system

You may qualify if:

• Signed informed consent.
• Patients with at least one extracoronal adhesive attachment for anchoring an RPD and patients with clasp-retained RPD during a 25-year period (2001 - 2025) at the Department for Reconstructive Dentistry or the affiliated student course.
• The attachment or clasp must have been in place for a minimum of six months at the time of clinical follow-up.
• Sufficient availability of medical/dental records
• Age ≥18 years at time of initial treatment.
• Ability to attend a clinical follow-up appointment.

You may not qualify if:

• Patients unable to provide informed consent.
• Incomplete or missing documentation of the prosthetic treatment.
• Attachments or clasps inserted less than six months ago.
• Inability to attend the follow-up appointment or language barriers preventing study understanding.

Sponsors & Collaborators

• University of Basel: lead

Study Sites (1)

Universitäres Zentrum für Zahnmedizin Basel - Klinik für Rekonstruktive Zahnmedizin

Basel, Basel, 4058, Switzerland

Location

Related Publications (7)

• Schaffer H. [Clinical results of partial denture anchorage using extracoronal bonded attachments]. Dtsch Zahnarztl Z. 1990 Jun;45(6):326-8. German.

  PMID: 2269117 BACKGROUND

• Besimo C, Gachter M, Jahn M, Hassell T. Clinical performance of resin-bonded fixed partial dentures and extracoronal attachments for removable prostheses. J Prosthet Dent. 1997 Nov;78(5):465-71. doi: 10.1016/s0022-3913(97)70061-1.

  PMID: 9399188 BACKGROUND

• Dula LJ, Kelmendi TZ, Shala K, Staka G, Pustina-Krasniqi T, Kosumi S. Attachment-Retained versus Clasp-Retained Removable Partial Dentures: Effects of Retention on Patient Satisfaction. Eur J Dent. 2025 Jul;19(3):823-834. doi: 10.1055/s-0044-1795122. Epub 2024 Dec 30.

  PMID: 39750515 BACKGROUND

• Kraljevic I, Glenz F, Jordi C, Zimmermann SD, Joda T, Zitzmann NU. Long-Term Observation of Post Copings Retaining Overdenture Prostheses. Int J Prosthodont. 2020 Mar/Apr;33(2):169-175. doi: 10.11607/ijp.6629.

  PMID: 32069341 BACKGROUND

• Zitzmann NU, Rohner U, Weiger R, Krastl G. When to choose which retention element to use for removable dental prostheses. Int J Prosthodont. 2009 Mar-Apr;22(2):161-7.

  PMID: 19418863 BACKGROUND

• Brandt S, Winter A, Lauer HC, Romanos G. Retrospective clinical study of 842 clasp-retained removable partial dentures with a metal framework: survival, maintenance needs, and biologic findings. Quintessence Int. 2024 Oct 24;55(9):704-711. doi: 10.3290/j.qi.b5566187.

  PMID: 38985439 BACKGROUND

• Garling A, Krummel A, Kern M. Outcomes of resin-bonded attachments for removable dental prostheses. J Prosthodont Res. 2024 Jan 16;68(1):100-104. doi: 10.2186/jpr.JPR_D_22_00306. Epub 2023 May 20.

  PMID: 37211411 BACKGROUND

Study Officials

• Nicola Zitzmann, Prof. Dr. med. dent. PhD

  University of Basel

  STUDY CHAIR

Study Design

• Study Type: observational
• Observational Model: COHORT
• Time Perspective: RETROSPECTIVE
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Member of Research Group of the Department of Clinical Research, Principal Investigator, Dr. med. dent.

Study Record Dates

• First Submitted: August 24, 2025
• First Posted: September 8, 2025
• Study Start: January 13, 2026
• Primary Completion (Estimated): December 1, 2026
• Study Completion (Estimated): December 1, 2026
• Last Updated: March 31, 2026

Record last verified: 2025-09

Data Sharing

• IPD Sharing: Will not share

Locations

CH (1)