Extracoronal Adhesive AttachmentNCT07160660
Patients' Satisfaction and Clinical Investigation of Removable Partial Denture Anchorage With Extracoronal Adhesive Attachments in Comparison With Clasp-retained Partial Dentures
An observational study of Extracoronal Adhesive Attachment and Clasp-retained Partial Dentures, run by University of Basel at 1 site in Switzerland.
Trial 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. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Extracoronal Adhesive Attachment, Clasp-retained Partial Dentures, Patients Satisfaction With Removable Dental Prostheses
- What is being tested?
- Patients' satisfaction and clinical investigation of removable partial denture anchorage with extracoronal adhesive attachments and Patients' satisfaction and clinical investigation of removable partial denture anchorage with conventional clasps
- How many people
- 250 participants
- Where
- 1 siteSwitzerland
- Study dates
- 13 Jan 2026to 1 Dec 2026
- Phase
- Observational
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
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
Who may be able to join
- 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.
Who cannot join
- 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.
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Switzerland1 site
Universitäres Zentrum für Zahnmedizin Basel - Klinik für Rekonstruktive Zahnmedizin
Basel, Basel, 4058
About this study
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.
Read more
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
- Extracoronal Adhesive Attachment, Clasp-retained Partial Dentures, Patients Satisfaction With Removable Dental Prostheses
- Being tested
- Patients' satisfaction and clinical investigation of removable partial denture anchorage with extracoronal adhesive attachments, Patients' satisfaction and clinical investigation of removable partial denture anchorage with conventional clasps
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Patients' satisfaction and clinical investigation of removable partial denture anchorage with extracoronal adhesive attachmentsOther
- 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' satisfaction and clinical investigation of removable partial denture anchorage with conventional claspsOther
- 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).
| Study group | Role | What they receive |
|---|---|---|
| Patients with extracoronal adhesive attachments as retentive elements of RPD (group A) | RDP = removable dental prostheses Receives: 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 Receives: Other: Patients' satisfaction and clinical investigation of removable partial denture anchorage with conventional clasps |
What is being measured
The primary outcome is the main question the study is designed to answer.
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.
Measured: 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
At the recall appointment, a clinical examination of the remaining dentition and the prostheses will be performed. The primary assessment will determine whether the abutment tooth with the attachment/clasp remains in situ. The secondary assessment includes a clinical evaluation of the periodontal and endodontic conditions. All biological complications such as caries lesions, tooth fractures, periodontal attachment loss, and endodontic pathologies of the abutment teeth will be reported in a standardized dental record.
If consent is given, relevant information from the existing dental records will also be extracted for analysis.
Measured: 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
At the recall appointment, a clinical examination of the remaining dentition and the prostheses will be performed. The assessment includes a clinical evaluation of the technical condition of the attachment/clasp and the RDP, such as comprise loss of retention between the extracoronal adhesive attachment and the corresponding matrice, loss of the matrice, debonding of the attachment, fracture of the attachment or clasps, deactivation of the clasps, fracture of the removable dental prostheses. The findings will be reported in a standardized dental record.
If consent is given, relevant information from the dental records will also be extracted for analysis.
Measured: From 2001 to present (RDP with retention element has to be in place for at least 6 months)
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted8 Sep 2025
- Study start13 Jan 2026
- Primary completion1 Dec 2026 (estimated)
- Study completion1 Dec 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (7)Papers the sponsor has linked to this study.
- Other trials for Extracoronal Adhesive AttachmentStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Cohort
- Time perspective
- Retrospective
- Enrolment
- 250 participants (estimated)
Sponsor and investigators
- Lead sponsor
- University of Basel
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Florence Auderset, University of Basel
- Investigators
- Nicola Zitzmann, Prof. Dr. med. dent. PhD, Study chair, University of Basel
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07160660
- Sponsor's protocol ID
- PSCI2025
- Status last verified
- Sep 2025
- First submitted
- 24 Aug 2025
- Last updated
- 31 Mar 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: During the clinical visit the questionnaire will be used as a paper case report form. Afterwards the data is transferred to an electronic database for later analysis and in the same step anonymized by using the patients code on the case report for further electronical storage of the collected data. Only study personnel will have access to it. Clinical parameters and patient satisfaction data will be used in encrypted form for statistical evaluation.
Publications
Schaffer H. [Clinical results of partial denture anchorage using extracoronal bonded attachments]. Dtsch Zahnarztl Z. 1990 Jun;45(6):326-8. German.
PubMed 2269117Besimo 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.
PubMed 9399188Dula 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.
PubMed 39750515Kraljevic 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.
PubMed 32069341Zitzmann 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.
PubMed 19418863Brandt 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.
PubMed 38985439Garling 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.
PubMed 37211411
Study at a glance
From the registry record, last updated by the sponsor on 31 Mar 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Patients' Satisfaction and Clinical Investigation of Removable Partial Denture Anchorage With Extracoronal Adhesive Attachments in Comparison With Clasp-retained Partial Dentures
- ClinicalTrials.gov ID
- NCT07160660
- Acronym / sponsor ID
- PSCI2025
- Conditions
- Extracoronal Adhesive Attachment, Clasp-retained Partial Dentures, Patients Satisfaction With Removable Dental Prostheses
- Study type
- Observational
- Recruitment status
- Enrolling by invitation
- Enrolment
- 250 participants (estimated)
- Lead sponsor
- University of BaselUniversity, hospital or other
- Study start
- 13 Jan 2026 (actual)
- Primary completion
- 1 Dec 2026 (estimated)
- Study completion
- 1 Dec 2026 (estimated)
- First posted
- 8 Sep 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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.
Study design
- Observational model
- Cohort
- Time perspective
- Retrospective
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Patients with extracoronal adhesive attachments as retentive elements of RPD (group A) | – | Other: Patients' satisfaction and clinical investigation of removable partial denture anchorage with extracoronal adhesive attachmentsRDP = removable dental prostheses |
| Patients with clasps as retentive elements of RPD (group B) | – | Other: Patients' satisfaction and clinical investigation of removable partial denture anchorage with conventional claspsRDP = removable dental prostheses |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
- 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
Key inclusion criteria (6 listed)
- 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.
Key exclusion criteria (4 listed)
- 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.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Patients' satisfaction and clinical investigation of removable partial denture anchorage with extracoronal adhesive attachments* 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). | Other | 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* 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). | Other | Patients with clasps as retentive elements of RPD (group B) |
Primary outcome
Patients' satisfaction with extracoronal adhesive attachments (group A) compared to conventional clasp-retained prostheses (group B) on a visual analogue scale (VAS)
Time frame: From 2001 to present (RDP with retention element has to be in place for at least 6 months)
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.
2 secondary outcomes
Occurrence of biological complications associated with the use of extracoronal adhesive attachments and conventional clasps
Time frame: 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
Time frame: From 2001 to present (RDP with retention element has to be in place for at least 6 months)
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 31 Mar 2026.
- Background: PubMed 2269117Schaffer H. [Clinical results of partial denture anchorage using extracoronal bonded attachments]. Dtsch Zahnarztl Z. 1990 Jun;45(6):326-8. German.
- Background: PubMed 9399188Besimo 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.
- Background: PubMed 39750515Dula 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.
- Background: PubMed 32069341Kraljevic 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.
- Background: PubMed 19418863Zitzmann 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.
- Background: PubMed 38985439Brandt 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.
- Background: PubMed 37211411Garling 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.
- Individual participant dataSharing planned: No. During the clinical visit the questionnaire will be used as a paper case report form. Afterwards the data is transferred to an electronic database for later analysis and in the same step anonymized by using the patients code on the case report for further electronical storage of the collected data. Only study personnel will have access to it. Clinical parameters and patient satisfaction data will be used in encrypted form for statistical evaluation.
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Nicola Zitzmann, Prof. Dr. med. dent. PhD study chair
University of Basel
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Extracoronal Adhesive Attachment and Clasp-retained Partial Dentures, run by University of Basel at 1 site in Switzerland.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 6 inclusion and 4 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: enrolling by invitation, as of the sponsor's last update on 31 Mar 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Switzerland. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Patients' satisfaction with extracoronal adhesive attachments (group A) compared to conventional clasp-retained prostheses (group B) on a visual analogue scale (VAS) (time frame: From 2001 to present (RDP with retention element has to be in place for at least 6 months)). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT07160660, which also lists 7 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 31 Mar 2026.