Condition category
Oral Health
Date applied
Date assigned
Last edited
Retrospectively registered
Overall trial status
Recruitment status
No longer recruiting
Publication status

Plain English Summary

Background and study aims
In the past, dental implant screws were placed in the jaw bone without teeth being added for 3-8 months to allow the bone to heal around the screw. More recently, immediate- and early-loaded implants are commonly used. Immediate-loaded implants have teeth attached to the screws within 72 hours from implant placement. Early-loaded implants are loaded approximately 6 weeks after implant placement. The aim of this 10-year study is to compare implant failures, complications, patient satisfaction and bone level of immediate and early loading of dental implants in people with some tooth loss.

Who can participate?
Adults with some remaining natural teeth requiring dental implants.

What does the study involve?
The participants were randomly allocated to the immediate or early loading group. Both groups had the dental implants inserted as usual. In the immediate loading group the implants were loaded with teeth within 72 hours from implant placement. In the early loading group, the implants were loaded with teeth approximately 6 weeks after implant placement. The implants were monitored for 10 years to measure the implant failure rate, implant complications, patient satisfaction with the function and appearance of the implants and bone loss measured by X-ray.

What are the possible benefits and risks of participating?
The potential benefit was that the immediate-loading group would not have to wait for 6 weeks to have teeth loaded onto their implants. The implant procedure has some risks including bleeding during and after implant placement, pain and swelling around the implant site, fracture of the implant or fracture of the artificial tooth.

Where is the study run from?
Clinica Merli, Rimini (Italy)

When is the study starting and how long is it expected to run for?
February 2005 to November 2018

Who is funding the study?
This study was investigator funded.

Who is the main contact?
Mauro Merli,

Trial website

Contact information



Primary contact

Dr Mauro Merli


Contact details

Clinica Merli
Viale Settembrini 17/O



Additional contact

Dr Michele Nieri


Contact details

Viale largo Brambilla 3

Additional identifiers

EudraCT number number

Protocol/serial number


Study information

Scientific title

Immediate versus early non-occlusal loading of dental implants placed flapless in partially edentulous patients: A 10-year randomized clinical trial


Immediate versus early loading

Study hypothesis

To compare immediate versus early non-occlusal loading of dental implants placed flapless

Ethics approval

This study started in early 2005 and at the time in Italy there was no a clear regulation for studies on a medical device.

Study design

Single-centre assessor-blind parallel randomized clinical trial

Primary study design


Secondary study design

Randomised controlled trial

Trial setting


Trial type


Patient information sheet

Not available in web format, please use contact details to request a participant information sheet.


Dental implantation in partially edentulous patients


Patients were randomized to receive implants for fixed partial dentures. The test group was represented by immediate non-occlusal implant loading, whereas the control group was represented by early non-occlusal implant loading. An investigator, not involved in the selection and treatment of the patients, randomly assigned participants following simple randomization procedures (computerized random numbers) to one of two treatment groups. The randomized codes were enclosed in sequentially numbered, identical, opaque, sealed envelopes. Envelopes were opened sequentially only after the implants to be included in the trial were inserted, and therefore treatment allocation was concealed to the investigator in charge of enrolling and treating the patients included in the trial.
All provisional restorations of the immediate loaded group were placed within 72 h of implant placement. The occlusal surface of the provisional restoration was ground to avoid any occlusal contact with the opposite dentition in static and dynamic analyses.
For patients in the early loading group, impressions were taken approximately 6 weeks after implant placement. They received non-occlusally provisional fixed restorations, identical to those of the immediately loaded group.

Intervention type



Drug names

Primary outcome measure

Implant failure (the presence of any mobility of the implant and/or any situation dictating implant removal) after 10 years

Secondary outcome measures

1. Biological or prosthetic complications defined as unexpected deviations from the normal treatment outcome: examples of biological complications are hemorrhaging during and after implant placement and/or peri-implantitis. Prosthetic complications included fracture of the implant or fracture of the prosthesis.
2. Patient's aesthetic and functional satisfaction were assessed by asking the patient for satisfaction on a scale from 0 to 10 where 0 meant completely dissatisfied and 10 meant completely satisfied
3. Peri-implant marginal bone level assessed using periapical intra-oral radiographs taken with the parallel technique at 10 years of follow-up

Overall trial start date


Overall trial end date


Reason abandoned (if study stopped)


Participant inclusion criteria

1. Aged 18 years or over
2. Partially dentate and requiring dental implants
3. Implant site allows for the placement of at least one 9.5 mm long implant
4. Bone thickness at the implant site at least 5.5 mm
5. For patients with multiple areas to be restored, the operator was free at the screening visit to select one area to be included in the trial. In this area, multiple neighboring implants could be placed.

Participant type


Age group




Target number of participants


Total final enrolment


Participant exclusion criteria

1. General contraindications to implant surgery
2. Patients irradiated in the head and neck area within a year prior to surgery
3. Patients with poor oral hygiene (full-mouth plaque score ≥30) and lack of motivation
4. Uncontrolled diabetes (diabetes that is not being treated at all, or is not being adequately treated)
5. Pregnant or lactating
6. Substance abusers
7. Psychiatric problems
8. Lack of opposing occluding dentition in the area intended for implant placement
9. Severe bruxism or clenching
10. Active infection or severe inflammation in the area intended for implant placement
11. Presence of ≤4 mm of keratinized mucosa and/or the need for bone augmentation procedures, with the exception of post-extractive sites treated with Bio-Oss® granules

Recruitment start date


Recruitment end date



Countries of recruitment


Trial participating centre

Clinica Merli
Viale Settembrini 17/O

Sponsor information


Clinica Merli

Sponsor details

Viale Settembrini 17/O

Sponsor type

Hospital/treatment centre



Funder type


Funder name

Investigator funded

Alternative name(s)

Funding Body Type

Funding Body Subtype


Results and Publications

Publication and dissemination plan

Two journal articles presenting the data up to 1-year and 3-year follow-up have been previously published. 10-year follow-up results are expected to be published in 2019.

IPD sharing statement:
The datasets generated during the current study will be available upon request from Mauro Merli ( after the publication of the trial at 10-year follow-up. Fields related to patient demographics will be deleted.

Intention to publish date


Participant level data

Available on request

Basic results (scientific)

Publication list

1. 2008 1-year follow-up results in
2. 2012 3-year follow-up results in

Publication citations

Additional files

Editorial Notes

26/03/2019: Third-party confirmation of the trial's existence is not available. This study started in early 2005 and at the time in Italy there was no a clear regulation for studies on medical devices. The trial was investigator-funded and -sponsored.