Influence of Vertical Implant Position on Marginal Bone Loss in Cases With Thin Phenotype

The Influence of Vertical Implant Position With Immediate Temporization on Marginal Bone Loss in Cases With Thin Soft Tissue Phenotype: A Randomized Controlled Clinical Trial

The goal of this clinical trial is to learn if vertical position of the dental implant will affect the bone around the implant in place of a missing tooth that happens to be bounded by two natural teeth. It will also measure esthetics and patient satisfaction. The main questions it aims to answer are:

Does vertical implant position below the crest of the bone lead to less marginal bone loss? Will it affect implant survival as well as quality of soft tissue, esthetics and patient satisfaction?

Participants will:

Have an implant placed at the bone level or 2 mm below the bone level Visit the clinic once every 3 months for checkups, radiographs, and readings

Study Overview

• Status: Recruiting
• Conditions: Tooth Loss / Rehabilitation; Vertical Implant Position; Delayed Implant Placement With Immediate Loading
• Intervention / Treatment: Procedure: Delayed implant with immediate temporization placed 2 mm subcrestal level; Procedure: Delayed implant with immediate temporization placed at the crestal level

Detailed Description

Preservation of crestal bone is crucial and must be prioritized from the onset of implant placement. Adequate amount of peri-implant bone contributes to esthetic success and implant stability. Crestal bone contributes to both esthetics and function. Resorption of crestal bone is seen as loss of interproximal papillary support and gingival recession, which gives way to peri-implantitis and compromises esthetics (Degidi et al., 2011).

With respect to the depth of insertion, implants can be placed at various levels in the bone, which affects the peri-implant tissues with the surrounding marginal bone. Therefore, placement of an implant in a deeper position with respect to the bone crest (subcrestal placement) has been suggested as a method that could contribute to maintain the peri-implant soft and hard tissues in comparison with crestal placement, though this affirmation is subject to controversy (Pellicer-Chover et al., 2019).

Study will be conducted in the Oral Medicine and Periodontology department, Faculty of Dentistry, Cairo University, Egypt.

Patients will be selected from the outpatient clinic of the department of Oral Medicine and Periodontology-Cairo University.

Each patient will be examined to confirm meeting the eligibility criteria. A full medical and dental history will be taken, and proper oral examination will be performed. Then a pre-operative cone beam computed tomography (CBCT) will be taken to examine both the bucco-lingual bone dimension and bone height and to ensure that the area of interest is free of any pathological lesions.

All the steps will be explained in detail to each patient and an informed consent will be taken from the patient to agree on their enrolment in the clinical trial. Then the patient will be treated first by phase I therapy for periodontal treatment through conventional supragingival scaling and subgingival debridement. Then strict oral hygiene instructions will be given and patients will be reassessed after a period of 4 weeks. Reassessment of the case is to ensure absence of any signs of inflammation and presence of normal tissues before the surgical procedure.

Clinical photographs will be taken at baseline, during surgery and at 3, 6 and 12 months postoperatively.

The patients will be randomly assigned into two groups:

Intervention group: Patients receiving delayed implant placed 2 mm subcrestal with immediate temporization

Control group: Patients receiving delayed implant placed equicrestal with immediate temporization

Surgical procedure:

1. Topical anesthesia will be administered using infiltration technique in the labial and palatal sides of the area of interest.
2. Full-thickness midcrestal incision to expose the bone.
3. Implant insertion will be performed according to the manufacturer's instructions; drills will be used sequentially until the required implant diameter is reached with insertion of the paralleling pin in the osteotomy site to evaluate the proper position in bucco-lingual and mesio-distal direction

4. Then the implant will be placed Intervention group: inserted 2 mm apical to the alveolar bone crest with adequate primary stability.

   Control group: inserted at the same level of the alveolar bone crest with adequate primary stability.

5. After implant insertion, a healing collar will be placed over the implant. Then the flap will be repositioned and sutured.
6. After suturing, the healing collar will be removed and a scan body will be inserted for digital impression and immediate temporary PMMA crown will be delivered over a temporary abutment for both groups.

Postoperative Care:

Postoperative medication:

Administration of:

1. Antiseptic mouth rinse with Chlorhexidine (0.12%) two times a day for 1 week.
2. Anti-inflammatory drugs (NSAIDS; Ibuprofen 400 mg three times daily for 3 days).
3. Antibiotic (Hibiotic 1gm) will be prescribed for the patient twice daily for one week.

Patient self-care instructions:

Post-operative instructions:

1. Each patient will be instructed to apply cold fomentation for the first 6 hours.
2. Avoid tooth-brushing at the surgical site for the first 14 days and proper rinsing after every meal starting from the second day.
3. Hot beverages will not be permitted for the first 24 hours.
4. Each patient will be instructed to rinse with Chlorohexidine mouthwash every 12 hours for 14 days.
5. The patient will be asked to contact the operator for any unexpected complications.
6. The sutures will be removed 10 days post-operative.

Follow-up:

Each patient will be evaluated at 3, 6, 9 and 12 months post-operatively.

• Study Type: Interventional
• Enrollment (Estimated): 30
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Egypt
  • Cairo, Egypt
    • Recruiting
    • Cairo University
    • Contact: Tala H Elbanna; Phone Number: 00201017770662; Email: tala.abdelfattah@dentistry.cu.edu.eg

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Patients with single missing upper anterior or premolar teeth
• Patients with minimum buccolingual width of 6 mm and mesiodistal width of 6 mm
• Patients with thin soft tissue phenotype
• Patients with healthy systemic conditions.
• Patients older than 18 years.
• Good oral hygiene.
• Cooperative patients who accept a one-year follow-up period.
• Patients who consent to being part of the study (sign an informed consent form).
• Adequate inter-arch space for implant placement.
• Favorable occlusion (no traumatic occlusion).
• Absence of allergy to the prescribed medications.

Exclusion Criteria:

• Patients with inadequate bone volume and/ or quality
• Patients with local root remnants
• Patients with inadequate wound healing
• Patients with signs of acute infection related to the area of interest.
• Patients with habits that may jeopardize the implant longevity and affect the results of the study such as parafunctional habits (Lobbezoo et al., 2006).
• Heavy smokers (more than 10 cigarettes per day) (Lambert, Morris and Ochi, 2000).
• Metabolic diseases such as diabetes or hyperthyroidism as well as systemic medications such as chemotherapy or bisphosphonates
• Pregnant or nursing women.
• Uncooperative patients.

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
Experimental: Delayed implant with immediate temporization placed 2 mm subcrestal level	Procedure: Delayed implant with immediate temporization placed 2 mm subcrestal level; 2 mm subcrestal placement
Active Comparator: Delayed implant with immediate temporization placed at crestal bone level	Procedure: Delayed implant with immediate temporization placed at the crestal level; crestal level placement

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Marginal bone loss (crestal bone loss)	measured linearly in mm by comparing periapical radiographs	Assessment at baseline, 3 months post-operative, 6 months post-operative, 9 months post-operative and 12 months post-operative

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Midfacial recession	Corono-apical distance measured from the incisal edge/cusp tip to the peri-implant soft tissue margin	0, 3, 6, 9, 12 months post-operative
Pink Esthetic Score (PES)	The pink esthetic score will be calculated on the parameters defined by (Fürhauser et al. 2005). Clinical photographs will be taken to evaluate peri-implant soft tissue through evaluating seven variables compared to a natural reference tooth including: mesial papilla, distal papilla, soft tissue level, soft tissue contour, alveolar process deficiency, soft tissue color and soft tissue texture, all using a 0-1-2 scoring system, 0 being the lowest and 2 the highest value. The maximum achievable PES is 14.	baseline, 3, 6, 9, 12 months post-operative
Gingival thickness	Gingival thickness will be measured using an anesthetic needle with a rubber stopper, trans-gingivally piercing tissues horizontally perpendicular to the long axis of the tooth/implant until the needle contacts bone, at 3 different points. Three readings will be taken mid-buccally at three different levels; 2 mm, 4 mm and 6 mm apical to the gingival margin. The length of the part of the instrument that penetrates into the soft tissue is measured in mm using a caliper.	baseline, 3, 6, 9, 12 months post-operative
Implant survival	A binary outcome, the definition of implant success was based on the clinical and radiographic criteria described by Buser et al. 1990; 1) absence of clinically detectable implant mobility; 2) absence of pain or any subjective sensation; 3) absence of recurrent peri-implant infection; and 4) absence of persistent radiolucency around the implant after 12 months of loading (Buser, Weber and Lang, 1990)	12 months post-operative
Post-operative patient satisfaction	A 12-item questionnaire is self-reported by the patients after 12 months post-operative; six questions with scores from 1 to 10 with the poorest score (not very satisfied) being 0 and the optimum score (satisfied) 10. The other six questions are yes or no questions (Derks et al., 2014)	12 months post-operative
Radiographic horizontal bucco-palatal bone changes	The bucco-palatal width of the alveolar bone will be measured perpendicular to the long axis of the alveolar bone; the three measurements will be at three levels: the implant platform, 2 mm and 5 mm from the platform. (Koerich et al., 2016).	baseline, 12 months post-operative
Radiographic vertical bone changes	Vertical bone height will be measured. Measurement will be taken at the highest point of the remaining labial/buccal plate of bone using the implant neck as a reference point. The difference between pre- and post-operative measurements will be determined as the gain in labial/buccal vertical bone dimension (Wu et al. 2019).	baseline, 12 months post-operative
Emergence angle	The angle between the tangent line of the restoration at the most coronal point of the buccal mucosa and the implant long axis (Wang et al., 2022).	baseline, 12 months

Collaborators and Investigators

• Sponsor: Cairo University

Study record dates

Study Major Dates

• Study Start (Actual): January 16, 2025
• Primary Completion (Estimated): February 1, 2027
• Study Completion (Estimated): February 1, 2027

Study Registration Dates

• First Submitted: March 16, 2026
• First Submitted That Met QC Criteria: March 16, 2026
• First Posted (Actual): March 19, 2026

Study Record Updates

• Last Update Posted (Actual): April 2, 2026
• Last Update Submitted That Met QC Criteria: March 29, 2026
• Last Verified: August 1, 2025

More Information

Terms related to this study

• Keywords: Vertical position; subcrestal; crestal; delayed implant placement with immediate loading; vertical dental implant position
• Additional Relevant MeSH Terms: Periodontal Diseases; Mouth Diseases; Stomatognathic Diseases; Tooth Diseases; Tooth Loss
• Other Study ID Numbers: PER 00-6-3-2; 4511906268 (Other Grant/Funding Number: Straumann)

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No