An interventional study of Delayed implant with immediate temporization placed 2 mm subcrestal level and Delayed implant with immediate temporization placed at the crestal level in Vertical Implant Position, Delayed Implant Placement With Immediate Loading and Tooth Loss / Rehabilitation, sponsored by Cairo University. Recruiting at 1 site in Egypt. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-04-02.
Sponsored by Cairo University · Not applicable, Interventional, and Treatment
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
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:
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.
Postoperative Care:
Postoperative medication:
Administration of:
Patient self-care instructions:
Post-operative instructions:
Follow-up:
Each patient will be evaluated at 3, 6, 9 and 12 months post-operatively.
165 studies on the registry are indexed under Tooth Loss; 44 are open to participants now.
This study's planned enrollment of 30 is close to the median of 30 across 120 interventional studies indexed under Tooth Loss.
Browse Tooth Loss studies →Cairo University is the lead sponsor of 4,941 studies on the registry; 1,458 are open to participants now.
Of its 37 completed or terminated interventional studies of FDA-regulated products, 5 (14%) have results posted.
Counted across the registry records on this site, refreshed daily.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Procedure: Delayed implant with immediate temporization placed 2 mm subcrestal level
Procedure: Delayed implant with immediate temporization placed at the crestal level
2 mm subcrestal placement
crestal level placement
Marginal bone loss (crestal bone loss)
measured linearly in mm by comparing periapical radiographs
Time frame: Assessment at baseline, 3 months post-operative, 6 months post-operative, 9 months post-operative and 12 months post-operative
Midfacial recession
Corono-apical distance measured from the incisal edge/cusp tip to the peri-implant soft tissue margin
Time frame: 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.
Time frame: 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.
Time frame: 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)
Time frame: 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)
Time frame: 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).
Time frame: 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).
Time frame: 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).
Time frame: baseline, 12 months
Started Jan 2025 (actual). Primary completion is estimated for Feb 2027, 25 months after the start.
Of 71 non-industry interventional studies with no phase under Tooth Loss, half reached primary completion within 28 months of starting (the median), counting those still running; a quarter within 12 and three quarters within 48. This study's planned 25 months is below that.
Counting every sponsor, half of 77 studies reached it within 28 months; a quarter within 12 and three quarters within 48.
How these figures are worked out, and which studies are left out of them.
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