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NCT Number: NCT07535528

Implant Placement Depth and Peri-Implant Tissue Outcomes

The primary aim of this randomized clinical trial is to evaluate the influence of subcrestal implant placement depth (-2 mm vs -4 mm) on peri-implant marginal bone level changes, including marginal bone loss and bone remodeling. Secondary outcomes include implant success, peri-implant probing depth (PPD), and bleeding on probing (BoP).

Partially edentulous patients requiring fixed implant-supported prosthetic rehabilitation with two implants in posterior maxillary or mandibular regions will be included. Implants will be placed subcrestally at either -2 mm or -4 mm from the bone crest, following a submerged healing protocol. Allocation to insertion depth will be randomized. Marginal bone level changes will be assessed using standardized periapical radiographs at second-stage surgery, prosthesis placement, and at 1, 3, 6, and 12 months after functional loading. PPD and BoP will be recorded at the same time points.

Active, Not Recruiting

This study is active but is not currently recruiting participants.

Key information

Conditions

Dental Implant Placement Marginal Bone Loss Soft Tissue Management in Subcrestal Dental Implants

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

University of Valencia

Valencia, 46003, Spain

Who can participate

Healthy volunteers accepted: Yes

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

Inclusion criteria

  • Patients ≥18 years old with partial edentulism.
  • Need for rehabilitation with fixed implant-supported prostheses in posterior regions.
  • Availability of minimum bone height for implants ≥6 mm in length.
  • Minimum bone width without the need for guided bone regeneration.
  • Supracrestal soft tissue thickness ≥2 mm.
  • Non-smokers or smokers of ≤10 cigarettes/day.
  • Plaque index and bleeding on probing <20%.
  • Probing depth ≤3 mm.
  • Signed informed consent.

Exclusion criteria

  • Systemic diseases contraindicating implant surgery.
  • Treatment with intravenous bisphosphonates.
  • Head and neck radiotherapy.
  • Uncontrolled diabetes.
  • Pregnancy or breastfeeding.
  • Alcohol or drug use.
  • Psychiatric disorders.
  • Need for bone regeneration procedures.
  • Inability to complete follow-up.
  • Implant failure during the study period.

Treatment and study plan

Subcrestal Implant Placement with Transmucosal Abutment and One Abutment-One Time Protocol

Procedure

Participants will receive bone-level dental implants placed subcrestally at either -2 mm or -4 mm below the bone crest in healed posterior sites of the maxilla or mandible, according to randomization. Implant placement will follow the manufacturer's drilling protocol, achieving a final insertion torque of at least 35 Ncm. A transmucosal abutment will be connected at the time of surgery, with height selected based on implant placement depth (2-3 mm for -2 mm placement and 4-5 mm for -4 mm placement). The abutment will be tightened to a final torque of at least 30 Ncm following a one abutment-one time protocol.

Primary outcomes

  1. Changes in peri-implant marginal bone level (mm)

    Time frame: From abutment placement (baseline time [TB]), 1 month post (T1), and at 3 (T3) (prosthetic loading) , 6 (T6), and 12 (T12) months after definitive prosthesis placement.

    Parallelized periapical radiographs will be obtained and a calibrated digital tool will be used to determine the vertical distance from the implant-abutment junction to the most coronal bone-to-implant contact on the mesial and distal sides. Unit of measure: Milimeters (mm)

Secondary outcomes

  1. Peri-implant probing depth (mm)

    Time frame: 1 month post-op (T1), and at months 3 (T3) (prosthetic loading) , 6 (T6), and 12 (T12) after definitive prosthesis placement.

    Peri-implant soft tissue condition will be assessed by recording PPD using a periodontal probe at six surfaces per implant (mesiobuccal, midbuccal, distobuccal, and the corresponding lingual/palatal sites) to calculate the mean of every implant. Unit of measure: Milimeters (mm)

  2. Bleeding on probing (presence/absence)

    Time frame: 1 month post-op (T1), and at months 3 (T3) (prosthetic loading) , 6 (T6), and 12 (T12) after definitive prosthesis placement.

    Bleeding on probing will be measured by gently passing a periodontal probe (using ~20-25g of force) to the base of the sulcus/pocket of the prosthesis at six surfaces per implant (mesiobuccal, midbuccal, distobuccal, and the corresponding lingual/palatal sites), then waiting 30 seconds to observe bleeding. It will be recorded as a dichotomous score (yes/no). Unit of measure: Percentage of sites showing bleeding per implant.

  3. Implant success

    Time frame: From the time of surgery through the end of the 12-month follow-up period after definitive prosthesis placement.

    Assessment of the implants will be performed by categorizing them into: success (optimal health), satisfactory survival, compromised survival, or failure.

Other outcomes

  1. Baseline characteristics

    Time frame: At enrollment time.

    Baseline variables will be collected for descriptive purposes and will not be combined into a single outcome measure. These include: age (years); sex (male/female); smoking habit (non-smoker or ≤10 cigarettes/day); brushing frequency (0, 1-2, or 3 times/day); edentulism type (interdental or free end); periodontal phenotype (thin or thick); antagonist type (natural teeth, tooth-supported bridge, implant-supported prosthesis, or removable prosthesis); cause of tooth loss (caries, periodontitis, or fracture); implant location (arch and quadrant); and soft tissue thickness (mm).

Sponsors and collaborators

Lead sponsor

University of Valencia

Other

Registry information

Official study title

Influence of Implant Placement Depth (-2 mm vs -4 mm Subcrestal) on Peri-implant Tissue Conditions: a Randomized Clinical Trial Protocol

Important dates

Study start
2026
Primary completion
2026
Study completion
2027
First posted
Apr 17, 2026
Registry last updated
Jul 13, 2026

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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