Partial EdentulismNCT07886762
Comparison of Two Dental Implant Types and Placement Depths on Bone Around the Implant in Adults Missing Back Teeth
A study testing issue-level implant placed at crestal level (Klockner Essential Cone) and Bone-level implant placed 2 mm subcrestally with one-abutment-one-time protocol (Klockner Vega) in people with Partial Edentulism and Dental Implants, run by Markel Diéguez-Pereira at 1 site in Spain.
Trial summary
The goal of this clinical trial was to compare two ways of placing and restoring dental implants in adults missing one or more back teeth. The main question it aimed to answer was: does a bone-level implant placed 2 mm below the bone crest, with a final abutment that is never removed, preserve more of the bone around… Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Partial Edentulism, Dental Implants, Alveolar Bone Loss
- What is being tested?
- issue-level implant placed at crestal level (Klockner Essential Cone) and Bone-level implant placed 2 mm subcrestally with one-abutment-one-time protocol (Klockner Vega)
- Type of treatment
- Medical device
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 30 participants
- Where
- 1 siteSpain
- Study dates
- 2 May 2022to 6 Nov 2024
- Phase
- Interventional
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
Who may be able to join
- Adults in good general health
- Missing one or more back teeth that can be replaced with a dental implant
- Healthy gums, with no active gum disease
- Good oral hygiene (plaque and gum bleeding scores below 20%)
- Enough jawbone to place an implant at least 4 mm wide and 8 mm long, with at least 1.5 mm of bone around the implant, as confirmed by a 3D dental scan (CBCT)
Who cannot join
- Smoking
- Uncontrolled diabetes
- Treatment with intravenous bisphosphonates (bone-strengthening drugs given by injection)
- Weakened immune system or treatment with immunosuppressive drugs
- Active cancer
- Previous radiotherapy to the head or neck
Show all 9Show fewer
- Pregnancy
- Untreated gum disease (periodontitis)
- Insufficient jawbone quality or quantity
Trial locations and contacts
1 site in 1 country.
About this study
Official title: Marginal Bone Remodeling and Peri-Implant Inflammatory Biomarkers Around Crestally Placed Tissue-Level and Subcrestally Placed Bone-Level Implants: A Prospective Randomized Study
The goal of this clinical trial was to compare two ways of placing and restoring dental implants in adults missing one or more back teeth. The main question it aimed to answer was: does a bone-level implant placed 2 mm below the bone crest, with a final abutment that is never removed, preserve more of the bone around the implant than a tissue-level implant placed at the level of the bone crest?
Each implant was randomly assigned by coin toss to one of the two treatments. Researchers measured the bone level around the implants on dental X-rays at crown placement, 6 months after loading, and at a final visit 12 to 24 months after loading. They also measured two markers of inflammation (IL-1β and MMP-8) in the fluid around the implants 6 months after loading.
Read the detailed description
Design. Prospective, parallel-group randomized clinical trial conducted in private dental clinics in northern Spain. Randomization was performed at the implant level by simple coin toss at the surgical planning stage; patients receiving more than one implant could receive both configurations. There was no allocation concealment. Radiographic assessors and laboratory staff were blinded to group allocation.
Interventions. Tissue-level implants (Klockner Essential Cone, 1.5 mm machined transmucosal collar, conical connection) were placed with the treated surface at the crestal level. Bone-level implants (Klockner Vega, internal hexagon with a 10° conical interface and integrated platform switching) were placed 2 mm subcrestally. In the bone-level group, a definitive 2 mm transepithelial abutment was connected 2 months after surgery and was not removed thereafter (one-abutment-one-time concept). All implants were placed after mucoperiosteal flap elevation under antibiotic prophylaxis (2 g amoxicillin 1 h before surgery) and restored with screw-cement-retained monolithic zirconia single crowns.
Radiographic assessment. Standardized periapical radiographs were taken with the long-cone paralleling technique, using film holders and individualized silicone bite registrations. Marginal bone level was measured with ImageJ, calibrated on the known implant thread pitch, by two independent examiners.
Biomarker analysis. Peri-implant crevicular fluid was collected with sterile paper points (20 s), stored at -79 °C and analysed by ELISA for IL-1β and MMP-8.
Statistical analysis. Marginal bone level was analysed with linear mixed-effects models including random intercepts for patient and implant, to account for the clustering of implants within patients and for repeated measurements.
- Conditions
- Partial Edentulism, Dental Implants, Alveolar Bone Loss
- Being tested
- issue-level implant placed at crestal level (Klockner Essential Cone), Bone-level implant placed 2 mm subcrestally with one-abutment-one-time protocol (Klockner Vega)
- Keywords
- bone-level implant, tissue-level implant, subcrestal placement, marginal bone loss, one-abutment one-time, platform switching, peri-implant crevicular fluid, IL-1 beta, MMP-8
- Medical subject headings
- Alveolar Bone Loss
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
issue-level implant placed at crestal level (Klockner Essential Cone)Device
Tissue-level dental implant with a 1.5 mm machined transmucosal collar and conical connection, placed with the treated surface at the level of the bone crest after flap elevation.
Bone-level implant placed 2 mm subcrestally with one-abutment-one-time protocol (Klockner Vega)Device
Bone-level dental implant with an internal hexagonal connection, 10° conical interface and platform switching, placed 2 mm below the bone crest. A definitive 2 mm transepithelial abutment was connected 2 months after surgery and never removed.
| Study group | Role | What they receive |
|---|---|---|
| Tissue-level implant, crestal placement | Active comparator | Klockner Essential Cone tissue-level implants (1.5 mm machined transmucosal collar, conical connection) placed with the treated surface at the crestal level and restored with monolithic zirconia single crowns. Receives: Device: issue-level implant placed at crestal level (Klockner Essential Cone) |
| Bone-level implant, 2 mm subcrestal placement | Experimental | Klockner Vega bone-level implants (internal hexagon with 10° conical interface and platform switching) placed 2 mm subcrestally. A definitive 2 mm transepithelial abutment was connected 2 months after surgery and was never removed (one-abutment-one-time protocol). Restored with monolithic zirconia single crowns. Receives: Device: Bone-level implant placed 2 mm subcrestally with one-abutment-one-time protocol (Klockner Vega) |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change From Baseline in Peri-Implant Marginal Bone Level at Final Follow-up
Vertical distance (mm) from the bone crest to the first implant thread, measured at the mesial and distal sites on standardized periapical radiographs (long-cone paralleling technique) with calibrated ImageJ software by two blinded examiners. Change is calculated as the baseline value minus the follow-up value; positive values indicate bone loss.
Measured: Baseline (prosthesis delivery), 6 months after loading, and final follow-up (12 to 24 months after loading)
Secondary outcomes (2)
Interleukin-1β Concentration in Peri-Implant Crevicular Fluid
IL-1β concentration (pg/mL) in peri-implant crevicular fluid collected with sterile paper points (20 s) and analysed in duplicate by ELISA. Values below the detection limit (0.4 pg/mL) were set at half the detection limit for analysis.
Measured: 12 months after loading
Matrix Metalloproteinase-8 Concentration in Peri-Implant Crevicular Fluid
MMP-8 concentration (ng/mL) in peri-implant crevicular fluid collected with sterile paper points (20 s) and analysed in duplicate by ELISA. Values below the detection limit (0.1 ng/mL) were set at half the detection limit for analysis.
Measured: 12 months after loading
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted21 Oct 2026
- Study start2 May 2022
- Primary completion6 Nov 2024
- Study completion6 Nov 2024
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Partial EdentulismStudies 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
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Model description
- Parallel-group design with randomization at the implant level (coin toss). Patients receiving more than one implant could receive implants of both configurations.
- Masking
- Single blind
- Who is masked
- Outcomes assessor
- Enrolment
- 30 participants (actual)
Sponsor and investigators
- Lead sponsor
- Markel Diéguez-Pereira
- Sponsor type
- University, hospital or other
- Collaborators
- Sociedad Española de Prótesis Estomatológica (SEPES)
- Responsible party
- Sponsor-investigator, Markel Diéguez-Pereira, MD Dental Clinic
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07886762
- Sponsor's protocol ID
- CEImPA 264/19
- Status last verified
- Oct 2026
- First submitted
- 14 Oct 2026
- Last updated
- 21 Oct 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No