Crestal Bone Changes Following Equi-crestal Versus Subcrestal Implant Placement

Radiographic Evaluation of Crestal Bone Changes Following Equi-crestal Versus Subcrestal Implant Placement in Mandibular Posterior Augmented Ridge. A Randomized Controlled Clinical Trial.

Statement of problem: The stability of peri-implant bone is a crucial factor for the long-term success of dental implants, where crestal bone plays a significant role in both the primary as well as the long- term implant stability. A bone loss of 1.5 mm during the first year of loading has been acceptable according to the early standards. However, more bone stability can be expected with the development in implant designs and surfaces over the past decades.

Aim of the study: the aim of this study is to radiographically assess the crestal bone changes following delayed implant placement in mandibular previously augmented posterior sites, comparing cases with equicrestal implant placement with subcrestal implant placement

Study Overview

• Status: Recruiting
• Conditions: Implant Therapy; Augmentation, Alveolar Ridge
• Intervention / Treatment: Procedure: Subcrestal implant placement; Procedure: Crestal implant placement

Detailed Description

Statement of problem: The stability of peri-implant bone is a crucial factor for the long-term success of dental implants, where crestal bone plays a significant role in both the primary as well as the long- term implant stability. A bone loss of 1.5 mm during the first year of loading has been acceptable according to the early standards. However, more bone stability can be expected with the development in implant designs and surfaces over the past decades.

Aim of the study: the aim of this study is to radiographically assess the crestal bone changes following delayed implant placement in mandibular previously augmented posterior sites, comparing cases with equicrestal implant placement with subcrestal implant placement.

Materials and methods: This prospective, parallel, randomized controlled clinical trial will have 36 participants who need implant placement at the posterior mandibular area where they previously received horizontal bone augmentation. They will be randomly allocated into 2 groups, where group A (test) will receive dental implant placed subcrestally and group B (control) will receive implant placed equicrestally. Crestal bone loss will be assessed by periapical radiographs at implant placement (T0), 3 months (T3), 6 months (T6), 12 months (T12) and 18 months (T18) following implant placement. Keratinized tissue width, and soft tissue thickness will be measured clinically by periodontal probe at the same time points. Buccal bone changes will be evaluated at 18 months compared with the preoperative cone beam computed tomography by fusion module. Patient satisfaction will be recorded at the end of the trial.

• Study Type: Interventional
• Enrollment (Estimated): 28
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Hani El Nahas Professor, Professor; Phone Number: 01221334637; Email: hani.elnahass@dentistry.cu.edu.eg
• Study Contact Backup: Name: Zainab Hafez Abdel Rahman, Lecturer; Phone Number: +0201221334637; Email: Zeinab.hafez@miuegypt.edu.eg

Study Locations

• Egypt
  • Cairo, Egypt
    • Recruiting
    • Misr International University
    • Contact: hani el Nahs professor, professor; Phone Number: 01221334637; Email: hani.elnahas@dentistry.cu.edu.eg
    • Contact: Suzy nabil Phd, Phd; Phone Number: 01224785645; Email: suzy.naiem@dentistry.cu.edu.eg
    • Principal Investigator: hani el nahas professor, Professor

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Patients older than 21 years.

• Patients having augmented (by 50/50 particulate xenograft and autogenous bone) edentulous posterior site with vertical bone height of > 10 mm in the mandible with a width of ridge ≥ 7 mm

  • Adequate Inter-arch space for implant placement
  • Favorable occlusion (no traumatic occlusion).
• Good oral hygiene.•Accepts 18 months follow-up period (cooperative patient)
• The patient provides informed consent.

Exclusion Criteria:

• Patients with inadequate bone volume and/ or quality
• Patients with remaining roots or with signs of acute infection related to the area of interest.
• Patients having systemic conditions that interfere with normal wound healing
• Patients with habits that may jeopardize the implant longevity and affect the results of the study such as parafunctional habits .
• Smoker patients.
• Pregnant women.

Study Plan

How is the study designed?

Design Details

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

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Subcrestal implant placement; Delayed implant placement 2 mm subcrestally in missing mandibular posterior site.	Procedure: Subcrestal implant placement; Delayed implant placement 2 mm subcrestally in missing mandibular posterior site.
Active Comparator: Crestal implant placement; Delayed implant placement equicrestally in missing mandibular posterior site.	Procedure: Crestal implant placement; Delayed implant placement equicrestally in missing mandibular posterior site.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Crestal bone changes	Periapical digital radiographs to determine the amount of crestal bone lose in mm	at baseline,3, 6 ,12 and 18 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Keratinized tissue width	Keratinized tissue width using periodontal probe in mm	at baseline, 3,6,12 and 18 months
Patient satisfaction	Questionnaire	at baseline, 6 ,12 and 18 months

Collaborators and Investigators

• Sponsor: Misr International University
• Investigators: Study Chair: hani el nahas professor, Professor, Misr International University

Study record dates

Study Major Dates

• Study Start (Actual): January 1, 2025
• Primary Completion (Estimated): July 1, 2026
• Study Completion (Estimated): December 1, 2026

Study Registration Dates

• First Submitted: January 3, 2025
• First Submitted That Met QC Criteria: January 3, 2025
• First Posted (Actual): January 6, 2025

Study Record Updates

• Last Update Posted (Actual): January 27, 2026
• Last Update Submitted That Met QC Criteria: January 26, 2026
• Last Verified: January 1, 2025

More Information

Terms related to this study

• Keywords: dental implants; crestal bone level changes; subcrestal implant position; crestal implant position; augmented ridge
• Other Study ID Numbers: Crestal Bone Changes

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