Comparative Analysis of Passive Fit and Time Efficiency in Allon-X Implants Protocols Using Photogrammetry, Splinted Scan Bodies, and Conventional Impression Technique
Phase: NA
Conditions: Passive Fit of Full-arch Implant Prostheses
Sponsor: October 6 University

Comparative Analysis of Passive Fit and Time Efficiency in All-
on-X Implants Protocols Using Photogrammetry, Splinted Scan
Bodies, and Conventional Impression Technique.
وحليل مقارن للالءمة السلبية تالكفاءة الزمنية في روتواوالت الكل على س من
الزرعات راستخدام التصايو القياسى تأجسام الاسح الاووبطة تالطويقة التقليدية
.للطبعات
A proposal submitted to the Faculty of Dentistry – October 6 University in partial
fulfillment of the requirements for the Master's degree in Prosthodontics.
By
Mohammed Fathy Abdelhamid
B.D.S, October 6 University, 2020
July 2025

Page 1 of 17
1. Administrative Information
1.1 Roles and Responsibilities
1.1.1 Chief Supervisor: Prof. Dr. Aml Mahmoud Ibrahim (A.M.I)

Professor of Prosthodontics, Faculty of Dentistry, Cairo
University.

Selection of the study design, supervision on the thesis, and
monitoring of data collection.
1.1.2 Co-Supervisor: Dr. Mai Hassan Diab (M.H.D)

Lecturer in Prosthodontics, Faculty of Dentistry, October 6
University.

Sequence generation, allocation concealment, randomization, and
data management.
1.1.3 Investigator: Mohamed Fathy Abdelhamid (M.F.A)

Master’s degree candidate, teaching assistant, Prosthodontics
Department, Faculty of Dentistry, October 6 University.

Responsibilities: Collection of data, preparation, and conduction of
research results.

Email: mo97.fathy@gmail.com

Phone: 01099632823
1.1.4 Ethics Committee, Faculty of Dentistry, October 6 University:
It is responsible for:

Ensuring that the trial does not violate privacy and provides
competent review of all ethical aspects of the project.
1.2 Proposal Registration

The trial will be registered in [ClinicalTrials.gov or another relevant
registry].
1.3 Funding: Self-funding.

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2. Introduction
2.1. Background and Rationale:
2.1.1. Statement of the Problem:
For edentulous patients undergoing full-arch rehabilitation, the All-on-X
rehabilitation approach has gained widespread acceptance. Achieving passive
fit of the prosthesis, which has a direct impact on long-term success, requires
precise transfer of implant placements from the patient to the lab model. The
gold standard for traditional procedures is open tray impressions with pick-up
copings. But new developments in digital dentistry have brought other methods
including photogrammetry and intraoral scanning using splinted scan bodies.. (1
&2)
2.1.2 Rationale for Conducting the Research
For edentulous patients undergoing full-arch rehabilitation, the All-on-X
treatment approach has proven to be a very successful option, providing
enhanced function, aesthetics, and patient satisfaction. Achieving passive fit,
which reduces mechanical stress on implants and prosthetic components and
reduces the possibility of problems such screw loosening, fracture, or marginal
bone loss, is crucial to the long-term effectiveness of implant-supported
prostheses.
Passive fit has traditionally been evaluated after prostheses are fabricated using
traditional open-tray impression techniques, which are regarded as the gold
standard because of their great precision and dependability. These approaches,
however, are challenging, technique-specific, and susceptible to human mistake
or material deformation.
Other methods include digital intraoral scanning with splinted scan bodies
and photogrammetry have become more appreciated due to the quick
development of digital dentistry.
Potential advantages of these digital
workflows include quicker digital data transfer to the lab, less chairside time,

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and improved patient comfort. In the context of the All-on-X procedure, there is
still no clinical data comparing the accuracy especially passive fit and time
efficiency of these more recent methods with traditional impressions, despite
these benefits.
Thus, the purpose of this study is to compare the time efficiency and passive fit
of three impression techniques: traditional open-tray impressions, digital
intraoral scanning with splinted scan bodies, and photogrammetry. The findings
will provide clinicians with evidence-based insights
into whether digital
alternatives can match or surpass traditional techniques in terms of accuracy
and workflow efficiency, ultimately supporting the transition toward more
modern, streamlined protocols in implant prosthodontics.
2.1.3 Review of Literature
Jasim et al., 2024
(3)
“The advent of digital dentistry has significantly
transformed
clinical
protocols
in
implant
dentistry.
Intraoral
scanning
technologies offer notable advantages over conventional impression techniques,
including enhanced patient comfort and expedited acquisition of clinical data.
However, the accuracy and reliability of intraoral scanners can vary depending
on the specific scanning system utilized and the environmental conditions under
which the data is captured. ”
Zembic et al., 2021 (4) “While digital planning and computer-guided surgery
have become standard practices in contemporary implant dentistry, the use of
digital implant scanning remains a relatively recent advancement within the
field. Digital impressions play a pivotal role in integrating the clinical and
laboratory stages of the digital workflow for fabricating definitive implant
prostheses. Intraoral scanners (IOS) generate digital impressions in the form of
Standard Tessellation Language (STL) files, which are subsequently used in the
design and production of both interim and definitive implant-supported
restorations. Additionally, STL files can be superimposed with data obtained

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from cone beam computed tomography (CBCT) or facial scanning systems,
enabling the construction of a comprehensive "virtual patient." This integration
facilitates more accurate diagnosis, enhanced treatment planning, and improved
patient management.”
Eldabe et al., 2025 (5) “Photogrammetry is an emerging digital technique that
utilizes optical imaging systems to reconstruct three-dimensional models
without the need for direct physical contact. This method has demonstrated
promising outcomes in terms of accuracy and reproducibility when compared to
conventional impression techniques and intraoral scanning. Despite these
advancements, the traditional open tray technique continues to serve as the gold
standard, owing to its well-established dimensional stability and clinical
reliability.”
Eid et al., 2024 (6) “The attainment of passive fit in implant-supported screw-
retained frameworks is widely regarded as a critical determinant of the
functional longevity and clinical success of implant prostheses. Inadequate
passive fit has been associated with a range of mechanical complications,
including screw loosening, fracture of implant-abutment components, and
potential implant failure.”
Waldecker et al. (2021) (7) “Time control which involves recording the time
taken for each scanning or impression-taking process. In clinical practice,
minimizing chairside time not only enhances patient comfort but also improves
overall workflow and productivity for dental professionals. By comparing the
time required for direct scanning using intraoral scanners versus indirect
scanning of conventional impressions, this study aims to provide insights into
the practicality and feasibility of digital workflows. Efficient procedures can
lead to better patient satisfaction and acceptance. Therefore, assessing time
control complements the primary outcome of accuracy, offering a more
comprehensive evaluation of the methods under investigation.

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2.1.4 Explanation for Choice of Comparators
Traditional open tray impressions are regarded as the gold standard because of
their passivity and consistency in relaying various implant sites. In this study,
they function as the control group for comparing the accuracy of modern digital
technologies, specifically photogrammetry and digital scanning using splinted
scan bodies. This facilitates the easy assessment of whether digital alternatives
provide equivalent or greater results(5).
2.2 Objectives
PICOT
- (P) Population: Patients requiring a full-arch maxillary implant-supported
fixed prosthesis (All-on-X concept).
- (I) Intervention:
Digital intraoral scanning using splinted scan bodies and photogrammetry for
implant position transfer.
- (C) Comparator: Conventional implant-level open tray impression technique
using pick-up copings (gold standard).
- (O) Outcomes:
- Primary Outcome: Passive fit
of the implant-supported framework,
measured as vertical marginal gap (in µm) at implant-abutment interfaces using
3D inspection software (Geomagic Control X)
- Secondary Outcome: Time efficiency of each impression-taking workflow,
measured as the total clinical time required to complete the procedure from
screwing the impression coping/scan body to final scan/impression verification.
(T) Time: Evaluation of outcomes will be performed immediately after
exposure of the implants and during impression procedures for fabrication of
the final prosthesis.

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2.3 Trial Design
In Vivo Clinical Study This is an interventional, three-arm comparative clinical
trial with a crossover design .
2.4 Research Question (Focused Question):
Does the use of photogrammetry and digital intraoral scanning with splinted
scan bodies provide comparable or improved accuracy in implant position
transfer as measured by passive fit and time efficiency when compared to the
conventional open-tray impression technique in the All-on-X treatment concept?
3. Materials and Methods
3.1 Participants, Materials, Interventions & Outcomes
3.1.1 Eligibility Criteria:
3.1.2.1. The Inclusion Criteria:
1- Age: Adults aged between 45 and 65 years.
2- Edentulism: Fully edentulous or partially edentulous maxilla requiring full-
arch rehabilitation.
3- Bone Availability: Sufficient bone volume in the maxilla to support at least
four implants according to the All-on-X.
4-
General
Health
Status:
Systemically
healthy
patients
with
no
contraindications to dental implant surgery (ASA I–II classification).
5- Oral Hygiene: Demonstrated ability to maintain adequate oral hygiene.
6- Patient Motivation: Willingness to participate in the study and comply with
follow-up visits and required maintenance protocols.
7- Prosthetic Need: Patients seeking a fixed, implant-supported prosthesis for
the maxilla due to missing teeth and inability to use removable prostheses
effectively.
8- Radiographic Evaluation: Acceptable radiographic findings showing no signs
of pathology, infection, or significant anatomical limitations.

Page 7 of 17
3.1.2.2. The Exclusion Criteria:
1- Medical Conditions:
- Uncontrolled systemic diseases such as diabetes mellitus, osteoporosis, or
immunosuppressive disorders.
- History of radiation therapy to the head and neck region.
2- Oral Conditions:
- Active periodontal disease or untreated caries.
- Presence of cysts, tumors, or other pathologies affecting the maxilla.
- Poor oral hygiene or inability to cooperate with post-operative care.
3- Anatomical Limitations:
- Insufficient bone volume to place at least four implants without extensive
grafting procedures.
- Maxillary sinus pathology or oroantral fistulas.
- Psychological or Behavioral Factors:
- Psychiatric illness or cognitive impairment that may interfere with treatment
compliance.
- Bruxism or parafunctional habits confirmed by clinical evaluation or patient
history.
4- Pregnancy:
- Pregnant or lactating women (due to potential risks related to surgical
intervention and radiographic exposure).
5- Implant Contraindications:
- History of previous implant failure or allergy to titanium.
- Current use of bisphosphonates or antiresorptive medications associated with
jaw osteonecrosis.
6- Smoking Habits: Heavy smokers (>10 cigarettes/day) considered a relative
contraindication due to compromised healing and increased implant failure rates.
7- Compliance Issues: Patients unwilling or unable to attend scheduled follow-
up appointments or adhere to postoperative instructions.

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8- Temporomandibular Joint Disorders (TMD):
Patients with a diagnosed or symptomatic temporomandibular joint disorder
(e.g., pain, clicking, locking, limited mouth opening, or muscle tenderness) will
be excluded from the study. TMD can affect mandibular stability, occlusal
accuracy, and jaw positioning during scanning or impression procedures, which
may introduce errors in data capture and compromise the reliability of marginal
and internal fit measurements.
3.1.2 Materials:
1- Implants: Implants will be placed according to the All-on-X concept.
2- Healing Abutments: Temporary healing caps used during osseointegration
phase.
3- Multi-unit Abutments: Angled abutments (0°, 17°, 30°) used to correct
angulation discrepancies for prosthetic rehabilitation.
4- Implant-Level Pick-up Impression Copings: stock impression copings
designed to fit directly onto implant analogs.
5- Open Tray System: Metal or plastic trays with access holes for screwing
down impression copings.
6- Polyvinyl Siloxane (PVS) Impression Material: Heavy-bodied PVS for tray
stabilization and Light-bodied PVS for fine detail reproduction around
impression copings.
7- Digital Scanning Components

Splinted Scan Bodies: Scan bodies designed to be screwed onto multi-unit
abutments for accurate intraoral scanning. Splinting bar to connect scan
bodies and enhance spatial stability.

Intraoral Scanner (IOS): For direct scanning splinted scan bodies and
photogrammetry.

Desktop Optical Scanner: For scanning conventional impressions and stone
casts.

Page 9 of 17
8- Photogrammetry Equipment: Intraoral photogrammetry scanner (IPS) for
complete arch implant-supported prostheses.
9- Master Model and Analog System:

Maxillary Acrylic Resin Printed Master Model which fabricated to simulate
the All-on-X implant configuration.

Implant Analogues: Accurate replicas of the selected implant system
embedded into the master model for testing purposes.
10- CAD/CAM Software and Hardware

CAD
Software:
will
be
used
for
designing
the
prosthesis
and
superimposing scans for accuracy analysis.

CAM Milling Machine: For fabricating frameworks from digital data.

3D Inspection Software: For measuring trueness and precision using RMS
deviation (Geomagic Control X).
11- Stop Watch: Will be used for calculate the time in seconds.
3.1.4. Interventions:
3.1.4.1. Procedures:
A- Preoperative Planning

Cone-beam computed tomography (CBCT) scans and intraoral scans will be
used for virtual treatment planning.

A surgical guided stent will be fabricated using CAD/CAM technology to
ensure accurate placement of implants according to the All-on-X concept.

The guided stent ensures optimal implant angulation, depth, and inter-
implant distances to facilitate prosthetic rehabilitation.
B- Implant Surgery

Guided surgery will be performed under local anesthesia using the pre-
fabricated surgical guide.

Implants will be placed following the All-on-X protocol.

Immediate postoperative radiographs will be taken to confirm implant
position and integration.

Page 10 of 17
C- Healing Period

Patients will undergo a healing period of 4–6 months to allow for complete
osseointegration.

During this time, patients will wear a removable provisional prosthesis.

Post-healing, patients will return for impression-taking procedures.
D- Impression/Scanning Techniques:
After the healing phase, each patient will undergo all three impression
techniques in a crossover design, meaning each participant serves as their own
control across the three interventions. Randomization will determine the
sequence of interventions.
Group I: Conventional Open Tray Impression Technique (Control Group) Procedure:

Custom trays will be fabricated for each patient, Pick-up impression copings
will be screwed onto the implants. Splinting of the impression coping will
be done. Polyvinyl siloxane (PVS) impression material will be loaded into
the tray. Light-bodied PVS will be syringed around the impression copings.
The tray will be seated carefully and allowed to set.

After setting, impressions will be poured with Type IV dental stone to
fabricate master casts. Master casts will be scanned using a desktop scanner
to generate digital models.
Group II: Digital Intraoral Scanning with Splinted Scan Bodies (Comparator 1)
Procedure:

Splinted scan bodies will be screwed onto the implants.

Intraoral scanning will be performed using Intraoral Scanner

Digital data will be exported as an STL file.

Direct digital model of implant positions captured intraorally.

Page 11 of 17
Group III: Photogrammetry technology (Comparator 2) Procedure:

Photogrammetry scan bodies will be fixed on the implants. High-resolution
images will be captured from multiple angles. 3D reconstruction software
will be used to create a digital model based on image triangulation.

Data will be exported as an STL file.

Digital model of implant positions generated via photogrammetry.
E- Common Steps for All Groups:
After obtaining digital impressions using the three different techniques
(conventional open-tray, intraoral scanning with splinted scan bodies, and
photogrammetry), the following standardized steps will be performed for all
participants:
1. Digital Framework Design
The STL files obtained from each impression technique will be used into CAD
software . A screw-retained implant-supported framework will be digitally
designed to match the planned prosthetic rehabilitation. The design will ensure
proper occlusion, anatomy, and passive seating on the master model.
2. Framework Fabrication
The designed framework will be milled from a cobalt-chromium (Co-Cr) alloy
block using a CAM milling machine . Each framework will be clearly labeled
according to the impression technique used.
3. Framework Scanning (Individual Scan)
Each fabricated framework will be scanned individually using a high-resolution
desktop optical scanner . This will generate a digital STL model of the
framework alone .
4. Framework Seating and Model Scanning
The framework will then be passively seated onto its corresponding master cast
or digital model derived from the impression technique. The framework-cast

Page 12 of 17
assembly will be scanned again using the desktop scanner to capture the spatial
relationship between the framework and implant positions.
5. 3D Superimposition and Passive Fit Evaluation
Using 3D inspection software (e.g., Geomagic Control X) , the individual
framework scan will be superimposed onto the scan of the framework seated on
the cast. Deviations at the implant-framework interface will be analyzed
quantitatively. The vertical marginal gap will be measured at each implant site
to assess the degree of misfit. Measurements will be expressed in micrometers
(µm) and averaged across all implants per framework.
6. Complete the steps for construction of the passivly fit final prosthesis which
will be screwed on the patient mouth.
3.1.4.2. Intervention group:

Group II: Direct scanning with intraoral scanner and splinted scan bodies

Group III: Photogrammetry technology.
3.1.4.3. Control group:

Group I: Conventional implant level open tray impression technique →
indirect scanning
3.1.4.4. Outcomes:

Primary Outcome: Passive fit measured using 3D inspection software
(Geomagic Control X).

Secondary Outcome: Time efficiency, assessed using stop watch and
measured by seconds.
3.1.5 Sample Size Calculation:
Sample size calculation was performed using G*Power version 3.1.9.7
based on the results of a previous study (Eid et al., 2024) (6) . A power

Page 13 of 17
analysis was designed to have adequate power to apply a two-sided
statistical test to reject the null hypothesis that there is no difference
between groups. By adopting an alpha level of (0.05) and a beta of (0.1),
i.e. power = 90% and an effect size (d) of (0.41867923) calculated based
on the results of a previous study. The predicted sample size (n) was (14
sample). The passive fit in implant prosthodontics through three digital
impression techniques “conventional impression, intraoral scanning, and
photogrammetry” will be evaluated and statistically compared.
3.2 Assignment of Interventions:
3.2.1 Allocation:
- Allocation Ratio: 1:1:1.
3.2.1.1. Randomization:
Block randomization performed by the chief supervisor.
3.2.1.2. Allocation concealment mechanism:
The allocation sequence will be kept with the co-supervisor concealed from the
primary investigator.
3.2.1.3. Implementation:
The chief supervisor is the person who will generate the allocation sequence
centrally and who is responsible for ensuring proper randomization and
allocation concealment.
3.2.2. Blinding:
Single-blinded study.

Page 14 of 17
3.3. Data collection, management, and analysis:
3.3.1. Data collection methods:
No data collection.
3.3.2. Data management:
Data entry by excel office 2016. The data entry will be on my own.
3.3.3 Statistical Analysis:
The collected data will be, tabulated, and statistically analyzed using
SPSS program (Statistical Package for Social Sciences) software version
23.0. Normality will be explored using the Kolmogorov-Smirnov and
Shapiro-Wilk Test.
Descriptive statistics will be done for numerical parametric data as
mean±SD (standard deviation) and minimum & maximum of the range
and for numerical non parametric data as median and 1st& 3rd inter-
quartile range, while it will be done for categorical data as number and
percentage.
Inferential analyses will be done for quantitative variables using Repeated
measures ANOVA tests for whether there are any differences between
related means, Post hock comparisons using Bonferroni correction.
Inferential analyses will be done for qualitative data using Chi square test
for independent groups. The level of significance will be taken at P value
<0.050 is significant, otherwise is non-significant. The p-value is a
statistical measure for the probability that the results that will be observed
in a study could have occurred by chance (8&9).
3.4. Monitoring:
3.4.1. Data monitoring:
There is no data monitoring committee for this trial.

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3.4.2. Harms:
Expectancy of inaccuracies in scan data leading to misfit prostheses, which
could lead to fracture and compromise the restoration's longevity and success.
3.4.3. Auditing:
Auditing will be done by the main and co-supervisors to assure quality of the
research methods and interventions.
4. Ethics and dissemination
4.1. Research ethics approval:
I am planning for seeking the research ethics approval from Faculty of
Dentistry, October 6 University, Research Ethics Committee.
4.2. Declaration of interest:
There is no financial or other personal interest of any nature or kind in any
product service.
4.3. Access to data:
I will finalize the trial dataset in adequate statement.
5. Appendices
5. 1. Informed consent form:
There will be an informed consent collected from the patients.
6. References:
1. Drancourt, N., Auduc, C., Mouget, A., Mouminoux, J., Auroy, P., Veyrune, J.
L., El Osta, N., & Nicolas, E. (2023). Accuracy of Conventional and Digital
Impressions for Full-Arch Implant-Supported Prostheses: An In Vitro Study.
Journal of personalized medicine, 13(5), 832.

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2. Papaspyridakos, P., Souza, A., Finkelman, M., Sicilia, E., Gotsis, S., Chen,
Y.-W., Vazouras, K., & Chochlidakis, K. (2022). Digital vs conventional full-
arch implant impressions: A retrospective analysis of 36 edentulous jaws.
Journal of Prosthodontics, 32 (1), 45–51.
3. Jasim, A. G., Abo Elezz, M. G., Altonbary, G. Y., & Elsyad, M. A. (2024).
Accuracy of digital and conventional implant-level impression techniques for
maxillary full-arch screw-retained prosthesis: A crossover randomized trial.
Clinical implant dentistry and related research, 26(4), 714–723.
4. Zembic, A., Müller, P., Nahles, S., & Filippi, A. (2021). Digital vs
conventional implant impressions in partially and fully edentulous patients: A
systematic review. The International Journal of Oral & Maxillofacial Implants,
36 (2), 341–352.
5. Eldabe, A. K., Adel-Khattab, D., & Botros, K. H. (2025). Accuracy of
intraoral photogrammetry in complete arch digital implant scanning: An in vivo
prospective comparative study. The Journal of Prosthetic Dentistry, S0022-
3913(25)00294-X. Advance online publication.
6. Eid, H. S., Zohdy, M. M., Nour, M., & Salah, T. (2024). A comparative
analysis of the passivity of fit of complete arch implant-supported frameworks
fabricated using different acquisition techniques. The Journal of Prosthetic
Dentistry, 131(3), 477-e1.
7. Waldecker, M., Rues, S., Rammelsberg, P., & Bömicke, W. (2021).
Accuracy of complete-arch intraoral scans based on confocal microscopy versus
optical triangulation: A comparative in vitro study. The Journal of prosthetic
dentistry, 126(3), 414–420.
8. Faul, F., Erdfelder, E., Lang, A., & Buchner, A. (2007). G*Power 3: A
flexible statistical power analysis program for the social, behavioral, and
biomedical sciences. Behavior Research Methods, 39(2), 175-191.