Loading Protocols for Dental Implants Placed in Healed Fully Edentulous Maxilla

Immediate Vs Early Loading Protocols in Rehabilitation of Healed Fully Edentulous Maxilla

The goal of this clinical trial is to compare immediate versus early loading protocols for complete implant-supported fixed dental prostheses in healed edentulous maxillae.

The main questions it aims to answer are:

• How does the timing of delivery of the prosthesis affect the stability of the implant and the surrounding soft and bone tissue?
• Does prosthesis delivery time affect quality of life and patient satisfaction? Researchers will compare immediate and early (6 weeks after implant placement) loading protocols in rehabilitation of fully edentulous upper jaw.

Participants will:

• Receive 6 dental implants in the edentulous upper jaw and after that complete fixed dental prostheses will be delivered immediately or 6 weeks after implant placement.
• Visit the clinic at the scheduled time for checkups and tests

Study Overview

• Status: Active, not recruiting
• Conditions: Tooth Loss / Rehabilitation; Maxilla
• Intervention / Treatment: Device: Immediate implant loading; Device: Early loading

Detailed Description

Surgical protocol Prior to surgery antibiotic prophylaxis (2 g amoxicillin with clavulonic acid or, in case of allergy, 0.6 g clindamycin, 1 hour before the procedure) and antiedema therapy (0.004 g dexamethasone 1 hour before the procedure) was administered. Patients rinsed their mouth using 15 mL of 0.12% chlorhexidine solution for 1 minute preoperatively. The surgical procedures were performed under local anesthesia using 4% articaine, 1:100.000 epinephrine. Centers of the intended implant sites were marked according to the reference marks present in the patient's existing complete removable denture that had been used as the radiographic stent. A midcrestal incision was made, then full-thickness buccal and palatal flaps were elevated. Implant sites were prepared by strictly adhering to the manufacturer's protocol for low-density bone using drills of increasing diameter (Institut Straumann). To provide adequate primary implant stability, underpreparation was performed: 1. In low-density type D3 bone, the profile drill was skipped; and 2. In low-density type D4 bone, the final sequence and profile drills were skipped. Intermittent drilling under copious irrigation was performed with low hand pressure and a physiodispenser running between 600 and 800 rpm. A total of 144 sites were prepared, followed by placement of 144 SLActive surface (Bone Level Tapered, Institut Straumann) implants. Bone quality was assessed according to the Lekholm and Zarb classification. In sites with dehiscence or fenestration resulting in an exposed implant surface, localized bone augmentation was performed using bovine-derived xenograft (Geistlich Bio-Oss, Geistlich, Wolhusen, Switzerland) and covered with a type 1 collagen membrane (Geistlich Bio-Gide, Geistlich). Healing screws (Institut Straumann; NC healing abutment Ø4.8 mm conical 5 mm and RC healing abutment Ø5 mm conical 6 mm) were placed and primary wound closure was achieved with 5-0 single resorbable sutures (AssuCryl Lactin, Assut Sutures of Switzerland, Pully-Lausanne, Switzerland). Patients were discharged with recommendations regarding dietetic and hygienic regimens. Antibiotic protocol consisted of 2 g amoxicillin with clavulonic acid (divided into 2 doses) or, in case of allergy, 1.8 g clindamycin daily (divided into 3 doses) for the following 5 days. Antiedema therapy (0.004 g dexamethasone) was administered 24 hours postoperatively. Prosthetic protocol After dental implant placement, patients were randomly assigned to immediate loading or early loading groups.

Implants for patients from Test Group were immediately loaded using S-R abutments (Institut Straumann) with temporary restorations. Patients from Control Group did not receive any kind of prosthetic temporization and were left with healing abutments. For Test Group an open-tray impression technique was used for provisional restoration. Impressions were made using: ASilicone material (Hydrorise implant, Zhermack, Badia Polesine, Italy), splinted impression posts (RC and NC impression post, Straumann) and a plastic impression tray (Miratray, Hager Werken, Duisburg, Germany). Provisional restorations were made digitally with polymethyl methacrylate (PMMA) (Telio CAD, Ivoclar Vivadent, Schaan, Lichtenstein). Plaster models with scan bodies were digitized with a laboratory scanner (3Shape E1, 3Shape, Copenhagen, Denmark). Final virtual design of provisional restoration was performed with 3D design software (exocad Matera 2.3, Exocad, Darmstadt, Germany). Drilling of PMMA blocks was performed in a 5-axis milling machine (Zenotec Select, Wieland, Pforzheim, Germany). The following final Straumann screw retained abutments for the prosthetic bridge (Institut Straumann) were chosen according to implant angulation and surrounding soft tissue height. For the interface between the screw-retained abutments and final prosthetic work, copings for screw retained abutments (Institut Straumann) were used and bonded to the final prosthesis.

At the end of the 6-week healing period for both groups, definitive prosthetic restorations were delivered. In preparation for the definitive prosthesis, a final open-tray impression was taken with an individual tray and polyether material (Impregum Soft, 3M Espe, Seefeld, Germany). An analog ceramic layering technique was performed in the process of producing a porcelain fused to metal restoration (Shofu Vintage Halo Porcelain, Shofu Dental Corporation, Ratingen, Germany). The metal framework was made using cobalt chromium metal powder material (Starbond Easy Powder 45, Scheftner, Mainz, Germany) with additive manufacturing technologies (EOS, Krailling, Germany).

• Study Type: Interventional
• Enrollment (Actual): 24
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Serbia
  • Belgrade, Serbia, 11000
    • Implant Center, School of Dental Medicine, University of Belgrade

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria:

1. Patients in good general health with no current history of systemic disease or medication use that could interfere with the treatment;
2. Patients with complete maxillary edentulism who had lost their teeth at least 6 to 8 weeks prior to the proposed ''allon- six'' implant rehabilitation; and
3. Clinically compliant patients consenting to be enrolled into the study.

Exclusion Criteria:

1. Active or chronic disease that affects bone metabolism or wound healing;
2. Diminished mental capacities that could mitigate the ability to comply with the protocol;
3. Residual roots or teeth;
4. History of maxillary augmentation;
5. Oral carcinoma or inflammatory changes; and
6. History of head and neck radiotherapy.

Study Plan

How is the study designed?

Design Details

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

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Immediately loading; Implants will be loaded with temporary prosthesis immediatelly after their insertion	Device: Immediate implant loading; Implants will be immediately loaded using S-R abutments (Institut Straumann) with temporary restorations. An open-tray impression technique was used for provisional restoration. Provisional restorations were made digitally with polymethyl methacrylate (PMMA) (Telio CAD, Ivoclar Vivadent, Schaan, Lichtenstein). Plaster models with scan bodies were digitized with a laboratory scanner (3Shape E1, 3Shape, Copenhagen, Denmark). Final virtual design of provisional restoration was performed with 3D design software (exocad Matera 2.3, Exocad, Darmstadt, Germany). Drilling of PMMA blocks was performed in a 5-axis milling machine (Zenotec Select, Wieland, Pforzheim, Germany). After 6 weeks they will receive final prosthesis.; Other Names: Test group
Active Comparator: Early loading; Implants will be left to heal with healing abutments for 6 weeks without prosthesis	Device: Early loading; At the end of the 6-week healing period, definitive prosthetic restorations were delivered. In preparation for the definitive prosthesis, a final open-tray impression was taken with an individual tray and polyether material (Impregum Soft, 3M Espe, Seefeld, Germany). An analog ceramic layering technique was performed in the process of producing a porcelain fused to metal restoration (Shofu Vintage Halo Porcelain, Shofu Dental Corporation, Ratingen, Germany). The metal framework was made using cobalt chromium metal powder material (Starbond Easy Powder 45, Scheftner, Mainz, Germany) with additive manufacturing technologies (EOS, Krailling, Germany).; Other Names: Control group

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Implant stability	Implant stability will be recorded by Osstell Mentor and Penguin using Resonance frequency analysis (RFA) method. Results were recorded on an implant stability scale (ISQ) from 1 to 100. The higher the ISQ, the more stable the implant was.21 Two consecutive measurements delivering the same ISQ values were considered authentic.	Implant stability will be measured at the time of implant placement (baseline) and at post-op week 6 (prior to delivery of definitive prosthetic restoration) and then after 5, 10 and 15 years

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Insertion torque	Insertion torque was measured with a torque wrench (Institut Straumann) and recorded in Ncm.	During surgery, at implant placement in prepared implant site.
Marginal bone loss change from baseline to 5,10 and 15 years follow up	Following prosthesis and multiunit abutment removal, standardized healing abutments (identical to baseline protocol) were placed. CBCT images were acquired at the same exposure parameters as baseline and analyzed by one blinded examiner using OnDemand3D software (Cybermed Inc., Seoul, South Korea). MBL was measured as the linear distance from the implant shoulder to first bone-implant contact at four sites per implant: mesial, distal, buccal, and palatal aspects.	At final prosthesis delivery (baseline), after 5,10 and 15 years follow up
Changes in Buccal Plate thickness from baseline to 5,10 and 15 years follow up	Following prosthesis and multiunit abutment removal, standardized healing abutments (identical to baseline protocol) were placed. CBCT images were acquired at the same exposure parameters as baseline and analyzed by one blinded examiner using OnDemand3D software (Cybermed Inc., Seoul, South Korea). BPT was measured perpendicular to the implant axis at two locations: 2 mm apical to the implant-abutment connection and at implant midlength.	At final prosthesis delivery (baseline) to 5,10 and 15 years follow up
Oral health-related quality of life	Oral health-related quality of life was evaluated using the OHIP-19 questionnaire. It consists of 19 questions and patients rated each item on a 5-point scale, where 0 indicated "never" and 4 indicated "constantly." The total OHIP-19 score was obtained by summing the scores from all questions. Lower score meant improved quality of life.	At implant placement (baseline), 1 month after definitive prosthesis delivery, and after 5,10 and 15 years
Patient satisfaction	Patients specified their level of satisfaction related to function, esthetics, and discomfort/pain by indicating a position along a 10-cm line between 2 endpoints where the beginning of the line was marked as complete unsatisfaction and the end as maximum satisfaction on Visual Analogue Scale.	At implant placement (baseline), 1 month after final prosthesis delivery and after 5,10 and 15 years follow up.
Implant survival rate	Implant survival was defined as implant in situ regardless of condition or peri-implant disease presence.	1 month after final prosthesis delivery, after 5, 10 and 15 years follow up
Prosthesis survival rate	Prosthesis survival was defined as original prosthesis in function with or without minor repairs.	1 month after final prosthesis delivery, after 5, 10 and 15 years follow up
Complications	Biological complications (implant failure requiring removal, peri-implantitis, peri-implant mucositis) and mechanical complications (prosthesis fracture, veneer chipping, screw loosening/fracture, abutment complications) were recorded.	1 month after final prosthesis delivery, after 5, 10 and 15 years follow up

Collaborators and Investigators

• Sponsor: University of Belgrade
• Collaborators: Institute Straumann AG, Basel, Switzerland

Publications and helpful links

General Publications

• Markovic A, Misic T, Janjic B, Scepanovic M, Trifkovic B, Ilic B, Todorovic AM, Markovic J, Dard MM. Immediate Vs Early Loading of Bone Level Tapered Dental Implants With Hydrophilic Surface in Rehabilitation of Fully Edentulous Maxilla: Clinical and Patient Centered Outcomes. J Oral Implantol. 2022 Oct 1;48(5):358-369. doi: 10.1563/aaid-joi-D-21-00045.

Study record dates

Study Major Dates

• Study Start (Actual): March 1, 2019
• Primary Completion (Estimated): March 1, 2035
• Study Completion (Estimated): March 1, 2035

Study Registration Dates

• First Submitted: May 1, 2026
• First Submitted That Met QC Criteria: May 1, 2026
• First Posted (Actual): May 7, 2026

Study Record Updates

• Last Update Posted (Actual): May 7, 2026
• Last Update Submitted That Met QC Criteria: May 1, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Keywords: dental implant; edentulous maxilla; implant loading protocol; complete implant-supported fixed dental prostheses
• Additional Relevant MeSH Terms: Periodontal Diseases; Mouth Diseases; Stomatognathic Diseases; Tooth Diseases; Tooth Loss; Investigative Techniques; Epidemiologic Research Design; Epidemiologic Methods; Research Design; Methods; Surgical Procedures, Operative; Prosthesis Implantation; Dentistry; Oral Surgical Procedures; Prosthodontics; Dental Implantation, Endosseous; Dental Implantation; Oral Surgical Procedures, Preprosthetic; Control Groups; Immediate Dental Implant Loading
• Other Study ID Numbers: 16/36

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: 1 month, 5 years, 10 years and 15 years outcomes will be published in the journal.
• IPD Sharing Time Frame: 2022-2036
• IPD Sharing Access Criteria: The investigators will share analyzed outcomes, surgical and prosthetic protocols.
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; SAP; ICF

Drug and device information, study documents

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