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NCT Number: NCT07090863

Additively Versus Subtractively Manufactured Implant Supported Fixed Dental Prostheses

This research is being done to evaluate the clinical, technical, biological, and aesthetic results of two different fabrication methods (additive and subtractive) for creating implant-supported fixed dental prostheses (iFDPs). Patients will receive an iFDP, meaning an implant-supported crown, according to regular treatment protocols. The fabrication method used to create the implant-supported crown will be decided in a randomised way. Clinical and radiological examinations will be performed prior to and when receiving the implant-supported crown and during a follow-up period of 3 years. Furthermore, technician- and patient-reported outcomes will be evaluated used questionnaires.

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Key information

Conditions

Dental Prosthesis, Implant-Supported

Age range

20 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Center of Dental Medicine, University of Zurich, Zurich, Canton of Zurich, Switzerland

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About this study

This study is designed as a randomised controlled clinical trial with a multi-centre design. Patients in need of a definitive posterior implant-supported crown will be enrolled in this study following predefined eligibility criteria at two different study centres (Harvard School of Dental Medicine, Harvard University and Center of Dental Medicine, University of Zurich). Patients will receive a single implant-supported crown fabricated according to group allocation (additively or subtractively manufactured). After crown delivery, patients will be followed-up for an observation period of 3 years. The primary outcome is the clinical performance of the implant crowns. Clinical, technical, biological, and aesthetic results as well as the technician- and patient-reported outcomes will be assessed.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Signed Informed Consent Form in English language
  • ≥ 20 years of age
  • In need of at least one definitive screw retained premolar or molar iFDP on an existing dental implant (Straumann AG)
  • Presence of at least one adjacent tooth at the implant site
  • Adequate oral hygiene
  • Capability to comply with the study procedures

Exclusion criteria

  • Pregnant or lactating women
  • Known or suspected non-compliance, drug or alcohol abuse
  • Severe periodontal and peri-implant disease

Treatment and study plan

AM manufacturing method

Device

additively manufactured implant-supported prostheses

SM manufacturing method

Device

subtractively manufactured implant-supported prostheses

Primary outcomes

  1. Clinical success

    Time frame: This outcome will be evaluated at the baseline and at the follow-up visits after 1 year, 2 years and 3 years

    The primary outcome is clinical success of the iFDPs, which is defined as the iFDPs being free of all complications over the entire observation period.

Secondary outcomes

  1. Efficiency during manufacturing (dental technician) (time)

    Time frame: Periprocedural

    Fabrication time for the iFDP will be measured in minutes. The time needed for the manufacturing (subtractively or additively), the post-processing and the cementation on to the titanium base will be measured using a stopwatch.

  2. Efficiency during manufacturing

    Time frame: Periprocedural

    The laboratory workflow during manufacturing will be assessed by the dental technicians using a questionnaire on success of the fabrication and postprocessing steps, and complications such as faulty/damaged iFDP. Dental technicians will report complications by answering yes/no to the occurrence of any complications, specifying occurred complications and reporting their quantity.

  3. Chairside adjustment time

    Time frame: Periprocedural

    The total mean time for chairside adjustment (min) at iFDP delivery. A stopwatch will be used to measure the minutes between removing the healing abutment of the implant and final insertion of the prostheses after finishing any potential adjustments (for example approximal/occlusal contacts, polishing)

  4. Survival rate

    Time frame: This outcome will be reported on the baseline visit and the follow-up visits after 1, 2 and 3 years

    Survival will be defined as the presence of the iFDP independent of technical, biological or aesthetic complications.

  5. Probing Depth

    Time frame: This outcome will be assessed at the baseline visit and the follow-up visits after 1, 2 and 3 years.

    Measured from the gingival margin to the bottom of the probable pocket to the nearest millimeter using a University of North Carolina (UNC15) periodontal probe with 1 mm markings (Hu-Friedy, Chicago, IL. USA) with a light probing force (≃ 0.2 N)

  6. Esthetic outcomes

    Time frame: This outcome will be assessed at the baseline visit and the follow-up visits after 1, 2 and 3 years.

    Standardized photographs, occlusal and buccal aspect will be taken from each patient at each visit for documentation purposes and for evaluating the esthetic aspects. Outcomes will be assessed by using modified criteria of United States Public Health Services (USPHS) (Barnes, Arpante et al. 1995).

  7. Technical outcomes

    Time frame: this outcome will be assessed at the baseline visit and the follow-up visits after 1, 2 and 3 years.

    Technical outcomes of the iFDP will be assessed using modified criteria of United States Public Health Services (USPHS) (Barnes, Arpante et al. 1995).

  8. Patient-reported outcomes

    Time frame: This outcome will be assessed at the baseline and follow-up visits after 1, 2 and 3 years

    Patient satisfaction to the treatment and iFDP will be assessed with questions on Visual Analogue Scale (VAS). Patients will be asked questions regarding their satisfaction on a scale of 0 (not satisfied) to 100 (very satisfied) with the prostheses.

  9. Adverse events

    Time frame: through study completion. This outcome will be reported at baseline and follow-up visits after 1, 2 and 3 years.

    Any Adverse Event (AE) related or possibly related to the study procedures.

  10. Bleeding on probing (BOP)

    Time frame: This outcome will be assessed at the baseline visit and the follow-up visits after 1, 2 and 3 years.

    Presence of bleeding within 30 s after gently probing. The percentage of positive answers will be calculated.

  11. Plaque control record

    Time frame: This outcome will be assessed at the baseline visit and the follow-up visits after 1, 2 and 3 years.

    Presence of plaque evaluated dichotomously. The percentage of positive answers will be calculated.

Study contacts

Contact information is provided by the study sponsor or research team.

Kevser Pala, Dr.med.dent

CONTACT

[email protected]

+41764084037

Sponsors and collaborators

Lead sponsor

Harvard Medical School (HMS and HSDM)

Other

Collaborators

  • University of Zurich

Registry information

Official study title

Additively (AM) Versus Subtractively (SM) Manufactured Implant Supported Fixed Dental Prostheses (iFDPs)

Important dates

Study start
2025
Primary completion
2029
Study completion
2029
First posted
Jul 29, 2025
Registry last updated
Aug 5, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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