Understanding root and canal structures in teenagers: a study on extracted mandibular premolars in Damascus

ISRCTN	ISRCTN93024803
DOI	https://doi.org/10.1186/ISRCTN93024803
ClinicalTrials.gov (NCT)	Nil known
Clinical Trials Information System (CTIS)	Nil known
Protocol serial number	UDDS-361-13032023/SRC-2654
Sponsor	Damascus University
Funder	Damascus University

Submission date: 17/03/2025
Registration date: 18/03/2025
Last edited: 18/03/2025

Recruitment status: No longer recruiting
Overall study status: Completed
Condition category: Oral Health

Prospectively registered

Protocol

Statistical analysis plan

Results

Individual participant data

Record updated in last year

Plain English summary of protocol

Background and study aims
The structure of dental roots is complex and varied so it's important to understand the pulp anatomy and structure for successful root canal treatment. This study looked at the number, length, and root canal structure of lower premolars taken from teenagers in Damascus.

Who can participate?
Adolescents aged 12-15 years with at least one intact lower premolar needing orthodontic extraction

What does the study involve?
The participants' premolars were measured and their root numbers were assessed and x-rayed to assess their morphology.

What are the possible benefits and risks of participating?
The main benefit is to assess the root canal structure of the Damascus population. No possible risks are proposed as this study is an observational study.

Where is the study run from?
Damascus University (Syria)

When is the study starting and how long is it expected to run for?
January 2023 to March 2025

Who is funding the study?
Damascus University (Syria)

Who is the main contact?
Dr Yasser Alsayed Tolibah, yasser94.tolibah@damascusuniversity.edu.sy or Yasseralsayedtolibah@gmail.com

Contact information

Dr Yasser Alsayed Tolibah
Public, Scientific, Principal investigator

Almazzeh Street
Damascus
20872
Syria

Phone	+963 (0)988812044
Email	yasser94.tolibah@damascusuniversity.edu.sy

Study information

Primary study design	Observational
Study design	Epidemiological study
Secondary study design	Epidemiological study
Study type	Participant information sheet
Scientific title	An epidemiological study of root number, length, and canal morphology in extracted mandibular premolars from adolescent patients in Damascus
Study objectives	The null hypothesis proposes that gender does not influence the number of roots, their length, or the canal morphology of mandibular premolars
Ethics approval(s)	Approved 15/03/2023, Damascus University (Almazzeh Street, Damascus, 20872, Syria; +963 (0)944372202; sdg@damascusuniversity.edu.sy), ref: 361
Health condition(s) or problem(s) studied	Root number, length, and root canal anatomy of extracted mandibular premolars
Intervention	The sample consisted of 250 recently extracted first and second MPs during orthodontic treatment of adolescents aged 12–15 years from Damascus at the Pediatric Dentistry, Orthodontics, and Oral and Maxillofacial Surgery Departments, Faculty of Dentistry, Damascus University. Premolars that had undergone endodontic treatment, or had internal/external resorption, deformities, open apices, or fractures during extraction were excluded. Each patient signed an informed consent form, stating that the extracted premolar would be used in an epidemiological study. Therefore, 216 first and 132 second MPs met the inclusion criteria, forming a total sample of 232 intact-root MPs. Each extracted premolar was assigned a number, and the patient's gender was recorded to accompany each premolar’s data. Soft tissues, bone fragments, and calculus were removed through scaling and polishing. At this stage, the number of roots and the maximum length of premolars were determined in millimeters with a digital caliper (WEN Digital Caliper, Performance Tool - Wilmar LLC, Kent, Washington, USA). Subsequently, two periapical radiographs were taken for each extracted premolar to provide a three-dimensional understanding of its canal morphology: one in the buccolingual direction and one in the mesiodistal direction. This was done using a portable radiographic unit (PRU) (HyperLight, Eighteeth; Changzhou Sifary Medical Technology Co., Ltd., Changzhou City, Jiangsu Province, China) with the following settings: exposure time of 0.08 seconds, 65 kVp, and 2.5 mA. The PRU was positioned perpendicular to the tooth's long axis and the surface of the digital sensor (EzSensor HD; Vatech, Gyeonggi-do, Korea) in both radiographs.
Intervention type	Other
Primary outcome measure(s)	1. Premolar root numbers counted immediately after premolar extraction 2. Premolar length measured in mm immediately after premolar extraction 3. Root canal morphology assessed immediately after premolar radiographing. Vertucci’s classification was adopted to assess the canal morphology in both radiographs in each premolar: Type I (1-1): A single canal from the pulp chamber to the apex. Type II (2-1): Two separate canals leave the chamber and merge near the apex to form a single canal. Type III (1-2-1): A single canal leaving the pulp chamber, dividing into two, then rejoining to form one canal. Type IV (2-2): Two separate canals from the pulp chamber to the apex. Type V (1-2): A single canal leaving the chamber and dividing into two separate canals at the apex. Type VI (2-1-2): Two separate canals leaving the pulp chamber, merging in the middle of the root, and dividing again into two short, separate canals at the apex. Type VII (1-2-1-2): A single canal dividing, merging, and then separating into two short, separate canals at the apex. Type VIII (3-3): Three separate canals in one root from the pulp chamber to the apex.
Key secondary outcome measure(s)	The gender effects on the root number (one, two, three or more roots), their length (in mm), and the canal morphology of mandibular premolars (Vertucci classification), assessed statistically after analyzing the data
Completion date	15/03/2025

Eligibility

Participant type(s)	Healthy volunteer
Age group	Child
Lower age limit	12 Months
Upper age limit	15 Months
Sex	All
Target sample size at registration	250
Total final enrolment	250
Key inclusion criteria	1. Adolescents in Damascus 2. Intact mandibular premolars
Key exclusion criteria	1. Syndromes patients 2. Premolars fractured during the extraction process
Date of first enrolment	30/03/2023
Date of final enrolment	15/01/2025

Locations

Countries of recruitment

Syria

Study participating centre

Damascus University, Faculty of Dentistry

Almazzeh ST, Damascus, Syria
Damascus
20872
Syria

Results and Publications

Individual participant data (IPD) Intention to share	Yes
IPD sharing plan summary	Available on request
IPD sharing plan	The datasets generated during and/or analysed during the current study will be available upon request from Yasser Alsayed Tolibah (yasseralsayedtolibah@gmail.com) The type of data that will be shared: patient age and gender with all data in an Excel file Dates of availability: by 01/01/2026 Whether consent from participants was required and obtained: consent was required and obtained

Study outputs

Output type	Details	Date created	Date added	Peer reviewed?	Patient-facing?
Participant information sheet	Participant information sheet	11/11/2025	11/11/2025	No	Yes

Editorial Notes

18/03/2025: Study's existence confirmed by Damascus University.