Plain English Summary
Background and study aims
Restorations in compromised endodontically treated teeth are aimed to (protect the remaining dental tissue from fracture, preventing the return of sepsis to the root canal system, as well as compensating for lost dental structures).
There are several ways to restore compromised endodontically treated teeth, one of them called post and core.
Several factors affect the fracture resistance of teeth restored with post and core: (post Length, post diameter, post design, post material, post fitting, core material, cement adhesion).
Fibreglass reinforced resin posts are often prefabricated posts, limiting their fitting of the channel's precise shape.
Even though the low elastic modulus of Fiber posts, but it,s elastic modulus still higher than dentine once about three times. So in our research, we looking for material has an elastic modulus more closely to the dentine once, and can be milled with CAD/CAM.
Recently a new dental material is introduced Poly Ether Ketone Ketones Called (PEKK), this material has similar characteristics to human bone, shock absorbent, lightweight.
The aim of this study is to compare the survival rates between the three groups: one-piece milled post and core from (PEKK), one-piece milled post and core from fibre-reinforced composite blocks and prefabricated fibre posts.
Who can participate?
Adults with destroyed lower premolars
What does the study involve?
Chosen teeth are randomly allocated into three groups for restorations supported with either one-piece milled post and core from (PEKK)or one-piece milled post and core from fibre reinforced composite blocks or prefabricated fibre posts. All teeth are assessed clinically at 3, 6, and 12 months and radiographically at 6 and 12 months after treatment.
What are the possible benefits and risks of participation?
The treatment may introduce a new material for fabricating posts and cores.
There are no known risks to participants as any failed treatments will be re-done using another method.
Where is the study run from?
Department of fixed prosthodontic Dentistry, Tishreen University, Lattakia, Syria)
When is the study starting and how long is it expected to run for?
May 2019 to December 2021
Who is funding the study?
Tishreen University, Syria
Who is the main contact?
Dr Naif Ghanem,
Dr Naser Baherli,
Evaluating the success of post and core system fabricated by Polyetherketoneketone (PEKK) material in restoring endodontically treated teeth: a randomized controlled trial
PEKK_ post and core_ endodontically treated teeth
Null hypothesis: There are no differences in survival rates between the three groups: one-piece milled post and core from (PEKK), one-piece milled post and core from fiber reinforced composite blocks and prefabricated fiber posts.
Alternative hypothesis: There are differences in survival rates between the three groups: one-piece milled post and core from (PEKK), one-piece milled post and core from fiber reinforced composite blocks and prefabricated fiber posts.
Approved 02/04/2019, The Institutional Review Board of Tishreen University (Tishreen University, Faculty of Dentistry, Department of Pediatric Dentistry), No. 2164
Randomized three parallel-groups clinical trial
Primary study design
Secondary study design
Randomised parallel trial
Patient information sheet
No participant information sheet available
damaged endodontically treated lower premolars with 2 or less remaining
cavity walls that is need post and core
A randomized three parallel-groups clinical trial was designed to evaluate the differences in survival rates between the three groups:
Group 1: one-piece milled post and core from (PEKK)
Group 2: one-piece milled post and core from fibre-reinforced composite blocks.
Group 3: prefabricated fiber posts (control group)
According to the patient identification number, restricted random allocation was performed by blocking with a block length of 3 and 6 based on a the website (Randomization.com) to achieve balance between groups in size. Double blinding will be used (patient and examiner).
The control group is the group of prefabricated fiber posts.
The primary endpoint was the loss of restoration for any reason. Secondary endpoints were tooth loss, post debonding, post fracture, vertical or horizontal root fracture, endodontic or periradicular conditions requiring endodontic retreatment, secondary
caries and failure of core build-up, and loss of restoration because of technical failures. The patients were recalled at 3, 6, and 12 months.
Primary outcome measure
The loss of restoration for any reason, conducted by using of an explorer at 3, 6, and 12 months post-treatment and periapical radiographic examination performed by use of a paralleling technique at 6 and 12 months post-treatment
Secondary outcome measures
Conducted by visual inspection at 3, 6, and 12 months post-treatment
1. Tooth loss
2. Post debonding
3. Post fracture
4. Vertical or horizontal root fracture
5. Endodontic or periradicular conditions requiring endodontic retreatment
6. Secondary caries
7. Failure of core build-up
8. Loss of restoration because of technical failures
Overall trial start date
Overall trial end date
Reason abandoned (if study stopped)
Participant inclusion criteria
1. Patients older than 18 years
2. Patients are required to have one mandibular premolar for which endodontic treatment is indicated
3. The remaining cavity walls of the premolar after endodontic treatment two or fewer
4. No or treated periodontitis with a maximum probing depth of 4 mm and no bleeding on probing
5. Tooth mobility not more than score 1
6. The premolar are required to be in occlusal function with a natural tooth following restoration and none are used as abutments for fixed or removable prostheses
7. A willingness to return for a follow-up examination for at least one year
Target number of participants
Participant exclusion criteria
1. Tooth will aim to serve as an abutment for fixed or removable prostheses
2. Medical contraindications to dental treatment
3. Poor oral hygiene
4. Teeth with failed endodontic therapy
5. Patients with severe parafunctional habits
Recruitment start date
Recruitment end date
Countries of recruitment
Trial participating centre
Faculty of Dentistry
Funding Body Type
Funding Body Subtype
Results and Publications
Publication and dissemination plan
The results will be published in one of the prosthodontic journals which are related to the Scopus group.
The results that will be published are:
1. Survival rates of (PEKK) posts and cores
2. A comparative study about two materials that are used to fabricate one-piece milled posts and cores
IPD sharing statement:
The datasets generated during and/or analysed during the current study are not expected to be made available due to confidetiality
Intention to publish date
Participant level data
Not expected to be available
Basic results (scientific)