Additive Versus Subtractive Manufacturing Techniques of Custom-Made Plates for the Fixation of Interforaminal Mandibular Fractures

Additive Versus Subtractive Manufacturing Techniques of Custom-Made Plates for the Fixation of Interforaminal Mandibular Fractures:A Randomized Controlled Trial

This study aims to compare the mechanical properties, including tensile strength, shear strength, and flexural strength, as well as the clinical outcomes of additive and subtractive manufacturing techniques used to fabricate custom-made plates for the fixation of interforaminal mandibular fractures. A total of 16 patients were included and allocated into two groups: one treated using plates fabricated with the additive manufacturing technique and the other with the subtractive manufacturing technique. Mechanical performance was evaluated using standardized biomechanical testing, while clinical outcomes were assessed during scheduled postoperative follow-up visits. The objective of the study is to determine which fixation approach provides superior biomechanical performance and favorable clinical healing outcomes.

Study Overview

• Status: Completed
• Conditions: Anterior Mandibular Fracture
• Intervention / Treatment: Device: additive plating group; Device: subtractive plating group

Detailed Description

This randomized clinical study included 18 patients who were assessed for eligibility. Two patients were excluded-one did not meet the inclusion criteria and another declined participation-leaving a final sample of 16 patients who were randomly allocated into two equal groups (n=8 per group). All included patients were followed throughout the entire study period, and none were lost to follow-up.

Both study groups demonstrated comparable baseline characteristics with no statistically significant differences regarding age, sex distribution, trauma side, cause of injury, type of fracture, and operative time. All surgical procedures were performed using standardized operative protocols, and postoperative evaluations were conducted at fixed intervals.

Clinical outcomes included wound healing status, postoperative edema, infection, and wound dehiscence. Functional performance was evaluated through maximum mouth opening measurements and patient-reported outcomes involving occlusion and self-chewing ability. Radiographic and mechanical assessments were also performed, including tensile strength, shear strength, and flexural bending tests for the fixation systems used in each group.

Across the follow-up period, both groups showed satisfactory wound healing, absence of infection or dehiscence, progressive improvement in mouth opening, and gradual restoration of occlusal stability and chewing function, with no significant intergroup differences in clinical parameters. Mechanical testing demonstrated significant differences between the two fixation systems.

All collected data were statistically analyzed, and outcomes were reported in accordance with CONSORT guidelines.

• Study Type: Interventional
• Enrollment (Actual): 16
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Egypt
  • Gharbia Governorate
    • Tanta, Gharbia Governorate, Egypt, 31527
      • Faculty of Dentistry, Tanta University

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child; Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Isolated or non-isolated mandibular fractures located between the mental foramina (interforaminal fractures).

Exclusion Criteria:

• Patients with relevant systemic diseases that affect bone healing.
• Comminuted fractures in which it is difficult to fix.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: additive plating group; Additive manufacturing typically describes any process where material is gradually added, layer by layer, to form a final product. The term is often used interchangeably with 3D printing and rapid prototyping, although rapid prototyping can also involve other techniques beyond additive methods	Device: additive plating group; Additive manufacturing is the process of creating parts by joining materials based on 3D model data, typically layer by layer, in contrast to subtractive and formative manufacturing methods. While most of the global activity in additive manufacturing currently involves polymer-based systems, there has been increasing interest and activity in fabricating metallic parts
Active Comparator: subtractive plating group; In subtractive manufacturing, objects are created by progressively removing material from a solid block or sheet through processes such as cutting, drilling, boring, or grinding. While these processes can be performed manually, they are more commonly executed using computer numeric control (CNC). CNC machining is the most widely used subtractive manufacturing process today	Device: subtractive plating group; In CNC machining, cutting tool removes material to achieve the desired geometry. The process involves using CAD to create the model to be machined and CAM to provide instructions to the CNC machine on how to remove the material. There are three major machining processes for material removal based on 3D models: turning, drilling, and milling. Additional subtractive manufacturing techniques, such as laser cutting, waterjet cutting, electrical discharge machining, and plasma cutting, are typically used for 2D machining

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Tensile Strength	Tensile strength will be measured using a universal testing machine (Instron) to evaluate the resistance of each plate to tensile forces according to standardized biomechanical testing protocols. Unit of Measure: Newton (N) Measurement Tool: Instron Universal Testing Machine.	After fabrication of the plates (baseline biomechanical assessment)
Shear Strength	Shear strength will be tested using the Instron universal testing machine to determine the resistance of the plate to shear loading. Time Frame: After fabrication of the plates (baseline biomechanical assessment) Unit of Measure: Newton (N) Measurement Tool: Instron Universal Testing Machine.	Immediately after fixation (within 24 hours)
Outcome Measure	Title: Overall Mechanical Stability Description: Overall biomechanical stability will be evaluated based on combined tensile, shear results. Time Frame: Within 24 hours after surgical fixation Unit of Measure: Stability index (unitless)	Immediately after fixation (within 24 hours)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Mouth Opening Measurement	Maximum inter-incisal distance will be measured using a digital caliper to assess functional recovery and detect any restrictions. Unit of Measure: Millimeters (mm) Measurement Tool: Digital caliper	1 week, 2 weeks, 1 month, 3 months, and 6 months after surgery
Wound Healing Score	Wound healing will be assessed using the Landry, Turnbull, and Howley Wound Healing Index, which evaluates tissue color, bleeding on palpation, granulation tissue, and overall appearance. Unit of Measure: Score (0-5 scale) Measurement Tool: Landry, Turnbull & Howley Index (clinical scale)	1 week, 2 weeks, 1 month, 3 months, and 6 months after surgery
Postoperative Edema Measurement	Edema will be measured using standardized linear facial measurements (tragus-pogonion and gonion-pogonion distances) to quantify postoperative swelling. Unit of Measure: Millimeters (mm) Measurement Tool: Facial linear measurement with ruler/caliper.	1 week, 2 weeks, 1 month, 3 months, and 6 months after surgery
Postoperative Infection Assessment	Infection will be evaluated using the CDC Surgical Site Infection (SSI) criteria, including redness, swelling, warmth, purulent discharge, fever >38°C, and localized tenderness at the surgical site.Unit of Measure: Presence or absence (Yes/No) Measurement Tool: CDC SSI Diagnostic Criteria (clinical assessment)	1 week, 2 weeks, 1 month, 3 months, and 6 months after surgery

Collaborators and Investigators

• Sponsor: Tanta University
• Investigators: Principal Investigator: FARIS I ALANAZI, Faculty of Dentistry, Tanta University; Principal Investigator: Rafic R Bedir, Faculty of Dentistry, Tanta University; Principal Investigator: Ahmed G Abushahba, Faculty of Dentistry, Tanta University

Study record dates

Study Major Dates

• Study Start (Actual): December 28, 2024
• Primary Completion (Actual): July 30, 2025
• Study Completion (Actual): October 29, 2025

Study Registration Dates

• First Submitted: November 16, 2025
• First Submitted That Met QC Criteria: November 23, 2025
• First Posted (Estimated): December 4, 2025

Study Record Updates

• Last Update Posted (Estimated): December 4, 2025
• Last Update Submitted That Met QC Criteria: November 23, 2025
• Last Verified: November 1, 2025

More Information

Terms related to this study

• Keywords: Fractures; Mandibular; Additive; Subtractive; Custom-Made Plates; Interforaminal
• Additional Relevant MeSH Terms: Wounds and Injuries; Fractures, Bone
• Other Study ID Numbers: TANTAOMSF-IFMF-149

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No