Influence of Implant Insertion Depth on Peri-implant Bone Changes Around Short Implants

March 9, 2026 updated by: Gulf Medical University

"Influence Of Crestal Versus Subcrestal Implant Placement Levels On Peri-Implant Health And Radiographic Bone Changes Around Short Implants: A Randomized Controlled Clinical Trial."

Dental implants are widely used to replace missing teeth and restore oral function and aesthetics. One of the key factors affecting the long-term success of dental implants is the stability of the bone surrounding the implant, particularly the crestal bone around the implant neck. Implant insertion depth relative to the alveolar crest may influence peri-implant tissue health and marginal bone remodeling.

This randomized controlled clinical trial aims to evaluate the influence of implant placement depth on peri-implant health and radiographic bone changes around short dental implants placed using guided surgical protocol. All implants will be placed using the Bicon Implant System following computer-guided implant planning and surgical guide fabrication to ensure precise implant positioning.

Participants requiring implant therapy will be randomly allocated into two groups. In the test group, implants will be placed 2 mm below the crestal bone level (subcrestal placement). In the control group, implants will be placed at the crestal bone level (crestal placement). Implant placement will be performed using guided implant surgery to standardize surgical positioning and minimize variability in implant angulation and depth.

Clinical parameters related to peri-implant health, including Modified Plaque Index, Implant Mucosal Index, Peri-implant Mucosal Tissue Index and Probing Depth during follow-up visits at 3, 6 and 12 months. In addition, standardized radiographic examinations will be performed to measure peri-implant Crestal bone level changes at 12 months.

The primary objective of this study is to determine whether subcrestal implant placement (2 mm below the bone crest) results in improved preservation of peri-implant crestal bone compared with crestal implant placement. Secondary outcomes will include assessment of peri-implant soft tissue health and overall implant stability.

The findings of this study may help clarify the optimal implant insertion depth for short implants placed using guided surgery and may contribute to improving long-term implant success and peri-implant tissue stability.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Detailed Description

Dental implants have become a predictable and widely accepted treatment modality for replacing missing teeth and restoring oral function, aesthetics, and patient quality of life. Long-term implant success is highly dependent on the preservation of peri-implant hard and soft tissues, particularly the stability of the crestal bone surrounding the implant neck. Early marginal bone remodeling following implant placement is considered a physiological process; however, excessive bone loss may compromise implant stability, prosthetic outcomes, and long-term implant survival.

Several factors have been suggested to influence peri-implant crestal bone remodeling, including implant design, implant-abutment connection, surgical technique, loading protocol, soft tissue thickness, and implant placement depth relative to the alveolar crest. Implant insertion depth has gained increasing interest because it may influence the establishment of peri-implant biologic width, soft tissue adaptation, and the position of the implant-abutment interface relative to the crestal bone. Subcrestal implant placement has been proposed as a potential strategy to improve marginal bone stability and optimize soft tissue emergence profile; however, evidence regarding its clinical benefits compared with crestal implant placement remains inconclusive.

Peri-implant health is typically assessed through a combination of clinical and radiographic parameters. Clinical parameters such as probing depth, plaque accumulation, bleeding on probing, and soft tissue condition provide important information regarding peri-implant tissue stability and inflammation. Radiographic evaluation remains essential for detecting marginal bone changes, which are considered a key diagnostic criterion for peri-implant disease progression and long-term implant success.

9. Periodontology 2000 - 2024 -…

The present randomized controlled clinical trial aims to evaluate the influence of implant placement depth on peri-implant health and radiographic crestal bone changes around short dental implants placed using a guided surgical protocol. The study will utilize the Bicon Implant System and a computer-guided implant placement workflow to ensure standardized implant positioning and minimize surgical variability. Digital implant planning will be performed using cone-beam computed tomography (CBCT) and virtual implant planning software. A surgical guide will be fabricated to allow accurate and reproducible implant placement according to the planned position.

Eligible participants requiring implant therapy will be randomly assigned to one of two treatment groups. In the test group, implants will be placed 2 mm below the crestal bone level (subcrestal placement). In the control group, implants will be placed at the crestal bone level (crestal placement). All implants will be placed using a guided implant surgery protocol to standardize implant angulation, position, and insertion depth.

Following implant placement, patients will undergo routine postoperative care and follow-up visits. Clinical parameters related to peri-implant health will be evaluated at 3, 6, and 12 months following implant placement. These clinical parameters will include:

Modified Plaque Index

Implant Mucosal Index

Peri-implant Mucosal Tissue Index

Probing Depth

These indices are commonly used to monitor peri-implant tissue conditions and detect early signs of inflammation or disease progression. Clinical probing and soft tissue evaluation provide essential diagnostic information regarding peri-implant mucosal health and tissue stability.

9. Periodontology 2000 - 2024 -…

Radiographic assessment will be performed using standardized periapical radiographs to evaluate peri-implant marginal bone levels. Radiographic measurements of crestal bone level changes will be performed at baseline and at 12 months after implant placement. The distance between the implant reference point and the first bone-to-implant contact will be measured to determine peri-implant marginal bone remodeling.

The primary outcome of the study is the evaluation of radiographic peri-implant crestal bone level changes after 12 months in implants placed at crestal and subcrestal levels.

Secondary outcomes include the assessment of peri-implant soft tissue health, including plaque accumulation, mucosal inflammation, and probing depth changes over the follow-up period.

This study aims to determine whether subcrestal implant placement (2 mm below the alveolar crest) provides improved preservation of peri-implant crestal bone and peri-implant tissue health compared with crestal implant placement when using a standardized guided implant surgery protocol.

The findings of this clinical trial may contribute to improving clinical decision-making regarding optimal implant insertion depth and may provide evidence-based guidance for implant placement protocols using short implants and guided surgical techniques.

Study Type

Interventional

Enrollment (Estimated)

58

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Locations

  • United Arab Emirates
      • Ajman, United Arab Emirates, 4184
        • Gulf Medical University
        • Contact:
        • Sub-Investigator:
          • Mohamed Atef Sayed, Ph.D.
        • Principal Investigator:
          • Marwa Mahayni, M.D.S
        • Sub-Investigator:
          • Hesham Marei, Ph.D.

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  1. Adults aged 18 years or older requiring dental implant therapy for replacement of a missing tooth in the posterior maxilla or mandible.
  2. Presence of sufficient bone volume to receive a short dental implant without the need for bone augmentation procedures.
  3. Patients in good general health or with controlled systemic conditions that do not contraindicate implant surgery.
  4. oral hygiene, defined as a plaque score ≤25%.
  5. Presence of healthy or treated periodontal tissues prior to implant placement.
  6. Patients willing and able to return for follow-up visits at 3, 6, and 12 months.
  7. Patients who provide written informed consent to participate in the study.

Exclusion Criteria:

  1. Patients with uncontrolled systemic diseases (e.g., uncontrolled diabetes mellitus, immunosuppressive disorders).
  2. History of radiotherapy in the head and neck region.
  3. Patients currently receiving bisphosphonate therapy or other medications affecting bone metabolism.
  4. Active periodontal disease or untreated oral infections.
  5. Heavy smokers (≥10 cigarettes per day).
  6. Presence of parafunctional habits such as severe bruxism or clenching.
  7. Patients requiring simultaneous bone grafting or sinus augmentation at the implant site.
  8. Pregnant or lactating women.
  9. Patients unable or unwilling to comply with the study protocol or follow-up schedule.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Double

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Subcrestal Implant Placement (2 mm Subcrestal)
Participants in this group will receive short dental implants placed 2 mm below the crestal bone level (subcrestal placement) using a fully guided implant surgery protocol. Implant placement will be performed using the Bicon Implant System following computer-guided implant planning and surgical guide fabrication to ensure standardized implant positioning and insertion depth. Clinical parameters of peri-implant health including Modified Plaque Index, Implant Mucosal Index, Peri-implant Mucosal Tissue Index, and Probing Depth will be evaluated at 3, 6, and 12 months. Radiographic evaluation of peri-implant crestal bone level changes will be performed at 12 months.
Procedure: Subcrestal Dental Implant Placement
Placement of short dental implants using a computer-guided surgical protocol with the implant positioned 2 mm below the alveolar crest (subcrestal placement). Implant placement will be performed using a surgical guide following digital implant planning to standardize implant position, angulation, and insertion depth. Short implants from the Bicon Implant System will be used. Postoperative evaluation will include clinical assessment of peri-implant health parameters (Modified Plaque Index, Implant Mucosal Index, Peri-implant Mucosal Tissue Index, and Probing Depth) at 3, 6, and 12 months, and radiographic assessment of peri-implant crestal bone level changes at 12 months.
Active Comparator: Crestal Implant Placement
Participants in this group will receive short dental implants placed at the crestal bone level (crestal placement) using a fully guided implant surgery protocol. Implant placement will be performed using the Bicon Implant System with computer-guided implant planning and surgical guide fabrication to standardize implant positioning and insertion depth. Clinical parameters including Modified Plaque Index, Implant Mucosal Index, Peri-implant Mucosal Tissue Index, and Probing Depth will be evaluated at 3, 6, and 12 months, and radiographic assessment of peri-implant crestal bone level changes will be performed at 12 months.
Procedure: Crestal Dental Implant Placement
Placement of short dental implants using a computer-guided surgical protocol with the implant positioned at the level of the alveolar crest (crestal placement). Implant placement will be performed using a surgical guide following digital implant planning to standardize implant position, angulation, and insertion depth. Short implants from the Bicon Implant System will be used. Clinical evaluation of peri-implant health parameters (Modified Plaque Index, Implant Mucosal Index, Peri-implant Mucosal Tissue Index, and Probing Depth) will be performed at 3, 6, and 12 months, and radiographic evaluation of peri-implant crestal bone level changes will be conducted at 12 months.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Radiographic Peri-implant Crestal Bone Level Changes
Time Frame: 12 months after implant restoration
Radiographic evaluation of peri-implant crestal bone level changes around short dental implants placed at crestal and 2-mm subcrestal levels. Cone-beam computed tomography (CBCT) scans obtained at baseline and at follow-up will be digitally superimposed using image analysis software to ensure standardized comparison. Reference lines will be established based on the implant long axis and fixed anatomical landmarks to measure vertical and horizontal bone level changes around the implant. The distance from the implant reference point to the first bone-to-implant contact will be measured on the buccal, lingual, mesial, and distal aspects. These measurements will be used to quantify peri-implant crestal bone remodeling and to compare bone level changes between the two study groups.
12 months after implant restoration

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Modified Plaque Index
Time Frame: at 3, 6 and 12 months following implant restoration

Assessment of plaque accumulation around dental implants using the Modified Plaque Index (mPI). The index will be recorded at four sites around each implant (mesial, distal, buccal, and lingual) to evaluate plaque accumulation on implant components. The scoring system will be as follows:

Score 0: No plaque detected.

Score 1: Plaque detected only by running a probe across the smooth marginal surface of the implant.

Score 2: Plaque visible to the naked eye.

Score 3: Abundance of soft plaque accumulation
at 3, 6 and 12 months following implant restoration
Implant Mucosal Index
Time Frame: 3, 6 and 12 months after implant restoration

Evaluation of peri-implant mucosal inflammation using the Implant Mucosal Index (IMI). After drying the peri-implant area, a periodontal probe will be gently moved (≤1 mm) in an encircling motion around the implant sulcus with light pressure directed toward the soft tissue. The presence and severity of bleeding or suppuration will be recorded after a few seconds. The scoring system is as follows:

Score 0: No bleeding.

Score 1: Minimal, single-point bleeding.

Score 2: Moderate, multiple-point bleeding.

Score 3: Profuse, multiple-point bleeding.

Score 4: Suppuration.
3, 6 and 12 months after implant restoration
Peri-implant Mucosal Tissue Index
Time Frame: 3, 6, and 12 months after implant restoration

Assessment of peri-implant soft tissue conditions using the Peri-implant Mucosal Tissue Index (MTI). This index evaluates the appearance, consistency, and texture of the peri-implant mucosa and is used to monitor peri-implant tissue health during follow-up. The peri-implant mucosa will be clinically examined around each implant, and the following scoring system will be used:

Score 0: Normal mucosa.

Score 1: Mild inflammation with slight color change and edema.

Score 2: Moderate inflammation with redness, edema, and glazing.

Score 3: Severe inflammation with redness, edema, and ulceration.
3, 6, and 12 months after implant restoration
Peri-implant Probing Depth
Time Frame: 3, 6, and 12 months after implant restoration
Measurement of probing depth around dental implants as The distance recorded in mm from the mucosal margin to the base of the pocket using a periodontal probe at six sites. This parameter will be used to evaluate peri-implant soft tissue health and detect potential peri-implant tissue changes.
3, 6, and 12 months after implant restoration

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Gulf Medical University

Investigators

  • Study Director: Mohamed Atef Sayed, Ph.D., Gulf Medical University
  • Principal Investigator: Marwa Mahayni, M.D.S, Gulf Medical University
  • Study Chair: Hesham Marei, Ph.D., Gulf Medical University

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

March 30, 2026

Primary Completion (Estimated)

May 30, 2027

Study Completion (Estimated)

May 30, 2027

Study Registration Dates

First Submitted

March 9, 2026

First Submitted That Met QC Criteria

March 9, 2026

First Posted (Actual)

March 13, 2026

Study Record Updates

Last Update Posted (Actual)

March 13, 2026

Last Update Submitted That Met QC Criteria

March 9, 2026

Last Verified

March 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • IRB-COD-STD-17-Sept-2025

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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