7 mm Versus 5 mm Diameter Immediate Post-Extractive Implants in the Molar Region: A Multicentre Randomised Controlled Trial
Phase: NA
Conditions: Partial Edentulism in the Maxilla or in the Mandible, Immediate Implant Placement
Sponsor: Marco Esposito

Official Title: 
7 mm versus 5 mm diameter immediate post-extractive implants 
in the molar region: a multicentre randomised controlled trial 
 
 
Brief Title: 
Comparing 7 mm and 5 mm Implants Placed Immediately After 
Molar Extraction 
 
 
NCT Number: 
NCT07041294 
 
 
Unique Protocol ID: 
NR430PROT 
 
 
Date of the Document: 
July 7, 2021 

 
Aims 
To compare the effectiveness of 7.0 mm-wide diameter implants with 5.0 mm-
conventional diameter implants placed immediately after tooth extraction in the 
molar region.  
 
Test hypothesis: there is no difference in clinical outcomes between the two 
procedures, against the alternative hypothesis of a difference. 
 
Study Design 
Multicenter randomized controlled trial (RCT) of parallel group design. Each patient 
will provide only one implant-supported crown. For patients with multiple teeth to 
be extracted, the operator will be free, at the screening visit, to select the tooth to be 
included in the trial. The trial will have a duration of 5 years post-loading. 
 
- 
Randomisation: using computer generated random numbers, centralized with 
sequentially sealed opaque envelopes provided by the study adviser. 
- 
Allocation concealment: operators will know about the intervention to be 
delivered by opening a sealed envelope after the tooth has been extracted.  
- 
Blinding: independent and blind assessors at each centre will assess implant 
stability. Bone level changes and aesthetic evaluation will be done by a single 
blinded and independent assessor who will evaluate the outcomes of all 
centers. 
 
The principles outlined in the Declaration of Helsinki on clinical research involving 
human subjects will be adhered to. A written informed consent will be obtained for 
each patient. 
 
The trial will be reported according to the CONSORT statement for improving the 
quality of reports of parallel-group randomized trials (http://www.consort-
statement.org/). 
 
Inclusion criteria 
Any patient requiring at least one single immediate post-extractive implant in the 
posterior jaw (molar areas only), being at least 18 year old and able to sign an 
informed consent. There must be sufficient bone to allow the placement of an implant 
at least a 7 mm-wide and 7 mm-long.  
Preoperative radiographs have to be taken. Investigators are free to choose the most 
appropriate examination according to the clinical case (intra-oral, panoramic, CT 
scans, etc.). 

Patients will be grouped into: 1) non smokers; 2) moderate smokers (up to 10 
cigarettes/day); 3) heavy smokers (more than 10 cigarettes/day), according to what 
they declare. 
 
Exclusion criteria 
- General contraindications to implant surgery. 
- Immunosuppressed or immunocompromised patients. 
- Patients irradiated in the head and/or neck. 
- Uncontrolled diabetes. 
- Pregnancy or lactation. 
- Active periodontal disease. 
- Poor oral hygiene and motivation. 
- Addiction to alcohol or drugs. 
- Psychiatric problems. 
- Patients with an acute infection (abscess) in the site intended for implant placement. 
- Necessity to lift the maxillary sinus. 
- Patients unable to commit to a 5-year follow-up. 
- Patients treated or under treatment with intravenous amino-bisphosphonates. 
- Lack of bony walls surrounding the future implant. 
- Patients participating in other studies, if the present protocol could not be fully 
adhered to. In case of doubts please contact the study coordinator. 
 
Study population and number of patients to be included 
Prior to enrollment, all patients will be asked to read and if they understood it, to sign 
an informed consent form to document that they understand the scope of the study 
(including procedures, follow-up evaluations, and any potential risks involved), were 
allowed to ask questions pertaining to this study, and were apprised of treatment 
alternatives. The study is open to qualifying patients without regard to sex or race. 
Seventy patients will be included, 35 in each group, each center treating 10 patients 
each.  
 
Outcome measures 
 
Crown failure: whether it will not be possible to place the crown because of implant 
failure or secondary to implant failure, or crown that has to be remade for any reason. 
 
Implant failure: Implant failure is defined as implant mobility and/or any infection 
dictating implant removal, and or/any mechanical problems rendering the implant 
unusable. The stability of each individual implant will be measured by the 
independent and blinded outcome assessor manually with a reverse torque of 20 Ncm 
at abutment connection and at delivery of the definitive crown, or by assessing the 

stability of the crown, using the handles of two metallic instruments, at 1 and 5 years 
after loading. 
 
Biological and biomechanical complications: will be recorded and reported by study 
group. Examples of biological complications are: fistula, peri-implantitis. Examples of 
biomechanical complications are fracture of the metal screws, loosening of the crown, 
fracture of ceramic. 
 
Peri-implant marginal bone level changes: digital intraoral periapical radiographs 
will be made with the paralleling technique at implant placement, implant loading, 1 
and 5 years after loading. In case of unreadable radiograph, the radiograph has to be 
made again. Radiographs will be converted to TIFF format with a 600 dpi resolution, 
and stored in a personal computer. Peri-implant marginal bone levels will be 
measured using the Scion Image (Scion Corporation, Frederick, MD, USA) software. 
The software will be calibrated for every single image using the known implant 
length or the diameter of the implant collar. Measurements of the mesial and distal 
bone crest level adjacent to each implant will be made to the nearest 0.01 mm. 
Reference points for the linear measurements will be: the coronal margin of the 
implant collar and the most coronal point of bone-to-implant contact. Bone levels 
will be measured at both mesial and distal sides and averaged. Bone level at single 
implants will be averaged at group level.  
 
Aesthetic evaluation of the clinical pictures, taken at delivery of the final 
restorations, 1 and 5 years follow-ups, on a computer screen by an independent 
blinded dentist. The pictures of the vestibular and occlusal aspects have to include the 
2 adjacent teeth, when present. The aesthetic evaluation will be done following the 
pink aesthetic score(1). 
 
Patient satisfaction: At the delivery of the final restorations, 1 and 5 years follow-up 
the independent outcome assessor at each centre will ask to the patient the following 
questions: 
1) Are you satisfied with the function of your implant supported tooth? Possible 
answers: yes absolutely, yes partly, not sure, not really, absolutely not. 
2) Are you satisfied with the aesthetic outcome of your implant supported tooth? 
Possible answers: yes absolutely, yes partly, not sure, not really, absolutely not. 
3) Would you undergo the same therapy again? Possible answers: “yes” or “no”. 
 
Materials 
Implant type: IB-T (ACH Medical, Gyeonggi-do, South Korea) tapered self-tapping 
implants, with an internal conical (11° per side) connection, a sand blasted, large grit, 

acid-etched surface, and body diameters of 5.0 or 7.0 mm. Operators are free to 
choose implant lengths (7.0, 8.0, 9.5 and 11.0 mm) according to clinical indications. 
 
Bone substitute: resorbable powder of non-collagenated trabecular bovine bone, 
having a granulometry of 0.2-1.0 mm (S1, MedPark, Busan, South Korea) and has to 
be hydrated with physiologic solution to become sticky. 
 
Definitive crowns: Screw-retained zirconia crowns. 
 
Clinical procedures 
 
Screening visit (APPENDIX 1) 
Potentially eligible patients are screened to establish their eligibility for the study. 
Please complete APPENDIX 1 (Patient eligibility CRF) and record the number and 
reason of non-included patients. Patients must be informed on the nature of the study 
and must sign an informed consent, if they understood the scope of the study and 
agreed to participate. A preoperative radiograph must be obtained for every included 
patient. 
After determining that the patient is qualified for the study, and informed consent has 
been given, a thorough oral examination will be performed to assess health status, 
identify oral pathologies that require treatment prior to implant therapy, and analyze 
available bone over vital structures and adjacent to remaining natural teeth. Severe 
caries and periodontal disease will be identified and treated. Implant selection is 
predicated on the location and anatomic morphology of the proposed implant 
receptor site and its contiguous structures. Therefore, radiographic examinations will 
be performed to assist with treatment planning and used as a screening tool to assess 
the patient’s overall dental health. To record a visual baseline, preoperative facial and 
occlusal digital photographs will be made of each patient intraorally to document the 
condition of the dental anatomy and state of soft tissue health. 
 
OPERATIVE PROCEDURES 
Please complete APPENDIX 2 (Surgical and prosthetic CRF) 
 
Prophylactic therapy: Patients will be administered 1 g amoxicillin 3 times a day for 
6 days starting the day before tooth extraction. Patients allergic to penicillin will be 
prescribed clindamycin 300 mg 3 times a day for 6 days starting the day before the 
intervention.  
Patients will rinse with chlorhexidine mouthwash 0.2% for 1 minute prior to the 
intervention. 
 
Local anaesthesia: Articain with adrenaline 1:100.000. 

 
Tooth extraction: Tooth extractions should be performed as atraumatically as possible 
attempting to preserve the buccal alveolar bone. Extraction sockets have to be 
carefully cleaned from any remains of granulation tissue. The wider diameter of the 
socket will be measured with a periodontal probe and reported in mm. 
 
Disclosure of the randomised allocation: Once the tooth has been extracted and 
whether there is sufficient buccal bone, the patient will be finally included in the 
study and the operator will know whether the patient will receive large or 
conventional diameter implant by opening a sealed envelope. It is absolutely 
forbidden to open the envelope containing the randomisation code before. It will be 
reported in the Surgical and prosthetic CRF (APPENDIX 2) the patient sequential 
number contained in the envelope and to which group the patient was allocated.  
 
Implant installation technique: drills will be used to prepare the implant site as 
suggested by the manufacturer. The intention is to stabilize the implant in the post-
extractive site. Implants will be placed slightly subcrestally, about 1 to 2 mm below 
the most apical bone peak. The largest residual gap between the bony walls and the 
implant will be measured with a periodontal probe in mm. Any residual gap between 
the implant and the socket walls will be filled with granular bone substitute. No other 
grafting material is allowed. 
Healing abutments will be placed and occlusal pictures showing the implants in place 
will be taken. 
A periapical radiograph just after implant placement has to be taken. 
Implants will be left to heal non-submerged for 4 months.  
 
Post-surgical instructions and follow-up:  
- Antibiotic prophylaxis previously described. 
- Ibuprofen 400 mg will be prescribed, but patients will be instructed not to take it in 
absence of pain. 
- Chlorhexidine mouthwash 0.12% for 1 minute twice a day for 2 weeks. 
 
Check-ups 
- 1 week after tooth extraction, all patients will be recalled and checked. Sutures will 
be removed.  
- 1 month after tooth extraction all patients will be recalled and checked. 
 
Four months after implant placement: 
- Implants will be manually tested for stability.  
- Impressions with pick-up or transfer-coping impression copings will be made with a 
polyether or a poly-vinylsiloxane material.  

- Definitive screw-retained zirconia crowns (previously cemented extra-orally) will 
be delivered within one month.  
- Periapical radiographs and clinical pictures of the study implants have to be made.  
- The satisfaction questionnaire has to be filled in. 
 
1 year after loading (APPENDIX 3):  
- Crowns will be manually tested for stability.  
- Periapical radiographs and clinical pictures of the study implants have to be taken. 
- The satisfaction questionnaire has to be filled in. 
 
5 years after loading (APPENDIX 3):  
- Crowns will be manually tested for stability. 
- Periapical radiographs and clinical pictures of the study implants have to be taken. 
- The satisfaction questionnaire has to be filled in. 
 
All patients will be recalled every 6 months for professional maintenance. 
 
In case of suspected implant loss, peri-implantitis, fistula, etc., observed during any of 
the scheduled visit or during an emergency visit, intraoral radiographs and clinical 
pictures have to be taken and the “Complications, protocol deviation and drop-out 
CRF” (APPENDIX 4) should be filled in. 
 
Time  
 
Day 1  
 
extraction/inclusion & allocation/implant placement/photos/rx 
Week 1 
 
post-op control 
Month 1 
 
post-op control 
Month 4 
 
implant stability/impression 
Within 1 month 
implant stability/definitive/rx/photos/questionnaire 
1 year postloading 
implant stability/rx/photos/questionnaire 
5 years postloading implant stability/rx/photos/questionnaire 
 
 
Drop-outs 
All drop-outs should be reported and the reason for dropping out should be investigated 
and reported per study group in APPENDIX 4. None of the included patient can be 
excluded for any reasons by the clinical investigators. 
 
Statistical analysis 
All data analysis will be carried out according to a pre-established analysis plan by a 
biostatistician with expertise in dentistry blinded to group allocation. A comparison 
of the baseline characteristics between groups will be presented. Differences in the 
proportion of crown/implant failures and other complications will be compared 

between the groups using a chi-square test. Means of continuous variables (marginal 
bone level changes, aesthetic scores) will be compared using an independent sample t-
test. Comparisons between, 1 and 5 years with the baseline measurements will be 
made by paired tests to detect any changes in marginal bone level changes for each 
study group with the baseline value as a covariate. All statistical comparisons will be 
conducted at the 0.05 level of significance. 
 
Administrative procedures and data management 
All centres are required to keep complete case report forms (CRFs) for all patients 
included in the study. CRFs should be filled in at the time of data collection. 
Complete CRFs, and memories containing the digitized clinical pictures and 
radiographs (radiographs can also be made on conventional films) should be attached 
to the study folder of each patient. 
All data requested for this study will be collected using paper CRFs. The CRFs will be 
stored in a secure locked place to which only the principle investigator and the 
responsible for data collection will have access to. Data will also be accessible to Dr 
Marco Esposito for monitoring and evaluation purpose at his discretion. After 
completion of the various follow-up points (1 and 5 years after loading) copies of al 
CRFs will be sent to the study coordinator, who will check the data, and store them 
in a computer pass-word protected. Data will be processed by an experienced 
statistician under supervision of the study coordinator. Patient identity will be 
protected and known only to the study participants listed in the present protocol. 
 
Publication plan 
1) 1 year after loading. 
3) 5 years after loading. 
 
Protocol amendments and violations 
Amendments to this protocol may be necessary and violations to the protocol are likely 
to occur. Any violation of the protocol should be reported in the “Complications, 
protocol deviation and drop-out CRF” (APPENDIX 4). In case of problems please 
contact the study coordinator without delay.  
 
Data ownership 
Data belongs to the investigators. 
 
Clinical research forms (CRFs) 
- Patient informed consent form  
- Patient eligibility CRF (APPENDIX 1) 
- Surgical and prosthetic CRF (APPENDIX 2) 
- Follow-up CRF (APPENDIX 3) 

- Complications, protocol deviation and drop-out CRF (APPENDIX 4) 
 
REFERENCES 
 
1. 
Fürhauser R, Florescu D, Benesch T, Haas R, Mailath G, Watzek G. Evaluation 
of soft tissue around single-tooth implant crowns: the pink esthetic score. Clinical 
Oral Implants Research 2005;16:639-644.