Evaluation of PEEK Versus Titanium Bar Attachments With Implant Assisted Mandibular Complete Overdenture Fabricated by CAD/CAM Technology
Phase: NA
Conditions: Edentulism in Lower Jaw
Sponsor: Tanta University

Official Title: Evaluation of PEEK Versus Titanium Bar 
Attachments 
with 
Implant Assisted 
Mandibular 
Complete Overdenture Fabricated by CAD/CAM 
Technology 
NCT Number: Not yet assigned 
Document Date: February 20, 2024 
 
 
 
 
 
 
 
 
 
 

Evaluation of PEEK versus Titanium Bar Attachments 
with Implant Assisted Mandibular Complete 
Overdenture fabricated by CAD/CAM Technology 
 
Protocol of Thesis Submitted in Partial Fulfillment of the 
Requirements for 
Doctor Degree 
 
In 
Prosthodontics 
 
 
 
Department of Prosthodontics 
Faculty of Dentistry 
Tanta University 
2024 

1 
Introduction 
Edentulism is considered a poor health outcome and may compromise 
the quality of life. According to the (World Health Organization) WHO, 
complete edentulism is affected by several factors including access to care, 
attitude towards dental hygiene, dentist/population ratios, oral health 
knowledge, education level, socioeconomic status, and lifestyle. The 
prosthetic management of the edentulous patient has been a major challenge 
for dentistry.1 
The classical treatment plan for the edentulous patient is the 
conventional complete denture, this treatment has several complications that 
occur frequently due to several factors as an atrophic alveolar ridge, thin 
mucosa covering it, reduced bony support, muscular factors, age of the patient, 
and its influence on adaptation.2 Wearing mandibular complete dentures (CD) 
is usually more problematic than maxillary CD because of the inherent 
displacing movement of the tongue and muscular borders, and decreased 
surface area. These problems direct the researchers to focus more on the lower 
jaw. Therefore, the problem of stability and retention of a complete denture is 
partially solved with the use of an overdenture.3 
Implant dentistry has given hope to edentulous patients in obtaining a 
prosthesis which is adequately retained, stable and comfortable as well. 
Insertion of implants creates a more favorable environment for restoration in 
such patients. Implant assisted prostheses options for edentulous arch include 
implant supported fixed prosthesis and implant supported removable 
prosthesis. While the first offers many advantages like being esthetically 
pleasing and feels like a natural dentition, they are very expensive and not 
indicated in many conditions. Due to the severe loss of mandibular alveolar 

2 
ridge, provision of fixed prosthesis would be inadequate to compensate for the 
loss of both soft and hard tissue, thus compromising the facial aesthetics.4,5 
With time, mandibular implant assisted complete overdenture IACO 
treatment has gained considerable acceptance. It is an attractive treatment 
option because of its relative simplicity, minimal invasiveness, and 
affordability. The prosthesis is supported by both implant and mucosa and 
generally requires fewer implants when compared with the totally implant-
supported prosthesis design. Fewer implants and a removable prosthesis offer 
a less complex and less expensive option for an edentulous patient and more 
hygienic.6 
The most common protocol used in IACO treatment is the placement of 
two implants in the anterior area of the mandible. This can be carried out in 2 
ways. It can be splinted implants by bar attachments or un splinted implants 
by stud type attachments7. Many factors affect attachment selection, such as 
jaw morphology, inter arch distance, the desired retention, prosthesis type, 
inclination and number of implants, financial options, and the availability for 
maintenance visits3. Bar attachment increases overdenture retention and is 
used to splint implants with the lowest complications in the prosthetic 
superstructure and maximum patient satisfaction. It offers stress-breaking 
action and cross-arch involvement, which allows occlusal forces to be shared 
between the abutments.9 
Three root form implants are placed in the A, C, and E positions for the 
second overdenture treatment option (OD-2). The advantages of splinting A, 
C, and E implants compared with implants in the B and D positions are many. 
The additional implant provides a sixfold reduction in superstructure flexure 
and limits the consequences previously discussed. In addition, screw 

3 
loosening occurs less frequently because three coping screws retain the 
superstructure rather than two. Implant reaction forces are reduced with a third 
implant compared with two implants.9 
The introduction and evolution of computer-aided designing and 
computer-aided manufacturing (CAD\CAM) technology in dentistry have 
greatly revolutionized treatment concepts and prostheses fabrication. Full 
digitalization leads to favorable clinical outcomes, better retention, fewer 
patient visits, potentially enhanced material properties and biocompatibility, 
advances in standardization of both clinical results and research, simplified 
identification of anatomical landmarks on digitized casts reproducible and less 
time-consuming tooth arrangements, easy data storage, and production of 
duplicate dentures10-12. 
In the prosthetic field, the digital revolution has a strong impact because 
the dentist can capture optical impressions with IOS these impressions are 
used by the dental technician for the planning and hence the production of a 
whole series of prosthetic restorations Patients favors optical impressions, 
which have eliminated the need for conventional analog impressions with 
trays and materials. The optical impressions also eliminate the discomfort 
linked to the conventional analog impressions; they are easy to capture for the 
clinician.  They can be sent directly to the dental laboratory by e-mail, at no 
cost. The dental technician can view the impressions and immediately give 
feedback to the clinician, while the patient sits comfortably in the dental chair 
with no time wasting.13-15. 
During the manufacturing of a conventional cast-bar attachment, 
dimensional changes can occur, associated with the impression-making and 
fabrication of an accurate dental cast, as well as the lost-wax casting protocol. 

4 
These dimensional changes (if poorly controlled) risk causing distortion.16 
Using CAD/CAM technology in overdenture prosthesis provides a 
computerized virtual bar design and modification, eliminating the laboratory 
steps such as casting and modelling. A good passive fit, lower distortion ratio 
and long-term success are observed in bar-retained overdentures produced 
with this technique.17  
 Various metals and alloys are commonly used in the fabrication of bar 
attachments. In the past, gold alloys were preferred but, due to their 
expensiveness and flexibility, this material is no longer preferred. Alternative 
materials for the fabrication of metal bar frameworks are: cobalt-chromium 
(Co-Cr), silver-palladium (Ag-Pd) alloys and titanium (Ti) and non-metallic 
restorations are used with metal allergy patients., Polyetheretherketone 
(PEEK) can be used as an alternative for a non-metallic framework.17 
PEEK was first developed in 1978 as a thermoplastic, polycyclic, semi-
crystalline polymer obtained by binding ketone and ether functional groups 
with aryl rings. It has superior mechanical properties, resistance to hydrolysis, 
chemical wear, and high temperatures with its low-weight advantage. The 
modulus of elasticity is close to alveolar bone and additional advantages are 
shock-absorbing.  It is a biologically inert material with no evidence of cyto- 
toxicity or immunogenicity. It also offers corrosion resistance, low plaque 
affinity, and minimal creep. Several studies reported that using PEEK as a bar 
attachment material has better resuts.17-20. 
Retention is the first factor responsible for patient satisfaction with the 
prosthesis, and it is defined as that quality inherent in the dental prosthesis 
acting to resist the forces of dislodgment along the path of placement. (33%) 
of prosthodontic complications are related to loss of retention. The rate of 

5 
attachment wear is related to its material of construction, which should be 
wear-resistant to maintain a stable retention force over-time. It was concluded 
that the least accepted retention force gained by different attachment systems 
in implant-retained overdenture was between 5 and 8 N in the long-term 
function.2,20,21.   
Research on OD3 is very rare. So the first  null hypothesis of this study 
is that there is no significant difference in retention , the second null hypothesis 
is there is no significant difference in bone lose around implant and the third 
null hypothesis there is no significant difference in bar diviation  between 
Titanium and PEEK bars fabricated by CAD/ CAM technology used with 
implant assisted mandibular complete overdenture. 
 
 

6 
Aim of the work 
Evaluation of OD retention, bone level around implant and bar deviation 
of PEEK versus Titanium Bar Attachments with Implant Assisted Mandibular 
Complete Overdenture fabricated by CAD/CAM Technology. 
 
 

7 
Materials and Methods 
Study design 
This study will be conducted as a clinical trial. 
Study setting 
This clinical study will be carried out at the Prosthodontic Department, 
Faculty of Dentistry, Tanta University and CAD-CAM laboratory. 
Patient selection: 
The patients will be selected from those attending the outpatient clinic 
of the Prosthodontic Department , Faculty of Dentistry, Tanta University 
on the following criteria: 
Inclusion criteria 
• Completely edentulous patients free from systemic diseases that may affect 
soft or hard tissue healing. 
• Patient's age ranges from 40 to 60 years old. 
• The bone quality and quantity of the mandibular alveolar ridge must fulfill 
the criteria for implant placement. 
• They have normal class Ӏ maxilla-mandibular relationship and sufficient 
inter-arch space with at least 25mm for bar attachment. 
• They have good oral hygiene. 
Exclusion criteria 
• Systemic disorders that may influence soft or hard tissue healing as oral 
diseases. 
• Patients with history of radiation therapy in the head and neck region. 
• Patients with neurological or psychological problems that may impair good 
oral hygiene. 

8 
• Patients with parafunctional habits. 
• Patients with heavy smoking, alcoholism, and drug abuse. 
Ethical consideration 
The purpose of the present study will be explained to the patients and 
informed consents will be obtained according to the guidelines on human 
research adopted by the Research Ethics Committee, Faculty of Dentistry, 
Tanta University. 
Patient number selection (power analysis) 
The total number of sample sizes for this study is 12 samples. The 
significance level was 0.05 and the power sample size was more than  80% 
for this study and the confidence interval 95 % and the actual power is 95.79%. 
The sample size is calculated based on a previous study 21; the calculations are 
done using a computer program G power version 3. 
The formula of sample size 
𝑠𝑎𝑚𝑝𝑙𝑒 𝑠𝑖𝑧𝑒=
(𝜎1
2 + 𝜎2
2) (𝑍𝛼+ 𝑍𝛽)
2
(∆−∆0)2
 
Where: 
Z = Z value (1.96 for 95% confidence level) 
𝛼= alpha level (The significance level was 0.05 ) 
𝛽= beta level. 
∆= difference under the null hypothesis 

9 
 
Fig1. Print screen of G power 3 software*  showing  samples size analysis 
 
 
 
*   G Power Analysis software, Heinrich Heine University Düsseldorf . Germany 

10 
Prosthetic procedures 
1. Accurate oral examination. 
2. Conventional CD will be fabricated that will be needed for digital implant 
planning and surgical guide designing and fabrication.  
3. Three relevant implants will be installed in ACE position in the mandible 
fig (2).
  
Fig (2) showing OD option 3 corresponds to implant in A, C,E positions are 
connected by bar.9  
4. After 3 months healing and osseointegration. Intra oral scanning will be 
carried out using an intra oral scan body to transport the correct implant 
position to the designing software. 
5. Hader bar will be designed. 
6. 3d printed model will be fabricated and digital analogs will be cemented. 
7. Verification jig will be fabricated and tried in the patient mouth. 
8. After verification, the designed bar will be milled. 

11 
9. A complete overdenture will be designed on the virtual model with the 
virtual bar. 
10. Conventional jaw relation will be performed and scanned by extra oral 
scan and the STL files will be stored in the software for virtual setting. 
11. Digital try in will be printed and tried in the patient mouth. 
12. The digitally designed complete overdenture will be completed digitally. 
13. Finally, the milled bar will be tightened in the patient mouth and the 
female housing (clips) will be direct picked up.  
Study groups. 
Group Ӏ (control group): 
Six patients will receive digital mandibular implant overdenture assisted 
by CAD/CAM Titanium bar attachment. 
Group II (study group): 
Six patients will receive digital mandibular implant overdenture assisted 
by CAD/CAM PEEK bar attachment. 
Methods of evaluation 
All patients will be evaluated radiographically, clinically, and digitally. 
• Radiographic evaluation 
Digital periapical X ray films will be carried out to measure marginal 
bone loss around implants at time of insertion of the prosthesis, after 6 months 
then after 1 year. 22, 23 
• Clinical evaluation 
Retention of the complete overdenture will be evaluated clinically at 
insertion time, after 6 months and after one year of insertion. Retention force 
will be measure in Newton’s using a digital retention testing device (Digital 

12 
force meter)   *which has wide range of force measurement (0-5000) gm, 
connect to a wire loop on the lower denture and pulled vertically. 21 
• Digital evaluation 
The deviation of the bar attachments will be evaluated digitally by 
superimposition the STL files recorded by scanning the bar during follow up 
after six months then after 1year over the reference data recorded at the time 
of insertion.24 
Statistical analysis: 
Statistical analyses will be performed using Statistical Package for 
Social Sciences (SPSS version 26). Numerical variables will be expressed by 
descriptive statistics as mean, standard deviation, and range, nominal data will 
be represented by frequency, percent and median. P value <0.05(*) was 
considered significant difference & P-value <0.001(**) was considered highly 
significant difference. 
 
 
 
 *47544Lanetech Instrument, cooperation, Beijing 

13 
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