Digital VS Conventional Altered Cast Technique for Mandibular Bilateral Distal Extension RPDs

NCT07583966 | Completed

• 1 other identifier: R-RP-5-21-10
• Study Type: interventional
• Target: 7
• Locations: 1 country
• Sites: 1

Brief Summary

This study aims to compare outcomes of digitally created altered casts with conventional altered casts in mandibular bilateral distal-extension cases.

Conditions

Mandibular Dimensions; Digital; Dentures

Keywords

mandibular; Altered Cast Techniques; Removable Partial Dentures; Digital

Outcome Measures

Primary Outcomes (1)

• Assessment of the condition of ridge mucosal covering of the Removable Partial Denture constructed out of digitally altered model.

  at 15 days, 3 months and 6 months .

Secondary Outcomes (1)

• Denture base fit by Pressure Indicating Paste

  one month

Study Arms (2)

Digital workflow and Digital altered cast group

EXPERIMENTAL

Digital selective tissue placement was performed within the same Exocad design project using the free-form scan-data tool, paint and pull feature to apply the principles of selective tissue pressure technique . Using free form mesh editing tools, the buccal shelf area opposing teeth 37 and 47 was identified, and controlled tissue ward displacement of the mucosal surface was simulated while monitoring the magnitude of displacement on sectional views and with digital measurement tools. Figure 2B, F The modified mandibular dataset was saved as the digitally altered cast STL (DA), which served as the basis for the digital RPD design and subsequent denture base fabrication.

Procedure: Digital workflow and Digital altered cast

Conventional workflow and conventional altered cast group

EXPERIMENTAL

For the CA cast technique, one of the SLM frameworks (MF2) was adapted on the stone master cast and used as a functional impression tray (Acrostone Dental Manufacturing, Cairo, Egypt) over the distal extension areas. A selec-tive pressure impression was made according to the traditional altered cast protocol, with the distal saddle areas repoured in dental stone to obtain the CA cast. This CA was then digitized using a desktop scanner (Dove Technologies, Suzhou, China) to produce the CA cast STL. Wax rims were used to verify the jaw relationship, and the maxillary cast was mounted using a facebow transfer on a semi adjustable articulator (A7 Plus, Bio-Art Equi-pamentos Odontológicos Ltda., São Carlos, SP, Brazil), while the mandibular cast was mounted in maximum intercuspation.

Procedure: Conventional Altered Cast Technique

Interventions

Digital workflow and Digital altered cast PROCEDURE

The RPD design features of fully digitally fabricated RPD illustrated in Figure 2A. Digital selective tissue placement was performed within the same Exocad design project using the free-form scan-data tool, paint and pull feature to apply the principles of selective tissue pressure technique . Using free form mesh editing tools, the buccal shelf area opposing teeth 37 and 47 was identified, and controlled tissue ward displacement of the mucosal surface was simulated while monitoring the magnitude of displacement on sectional views and with digital measurement tools.

Digital workflow and Digital altered cast group

Conventional Altered Cast Technique PROCEDURE

For the CA cast technique, one of the SLM frameworks (MF2) was adapted on the stone master cast and used as a functional impression tray (Acrostone Dental Manufacturing, Cairo, Egypt) over the distal extension areas. A selec-tive pressure impression was made according to the traditional altered cast protocol, with the distal saddle areas repoured in dental stone to obtain the CA cast. This CA was then digitized using a desktop scanner (Dove Technologies, Suzhou, China) to produce the CA cast STL. Wax rims were used to verify the jaw relationship, and the maxillary cast was mounted using a facebow transfer on a semi adjustable articulator (A7 Plus, Bio-Art Equi-pamentos Odontológicos Ltda., São Carlos, SP, Brazil), while the mandibular cast was mounted in maximum intercuspation. Semi anatomic acrylic teeth (Acrostone Dental Manufacturing, Cairo, Egypt.) were arranged, and wax try ins were evaluated intraorally in a conventional manner prior to processing.

Conventional workflow and conventional altered cast group

Eligibility Criteria

• Age: 40 Years - 60 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64)

You may qualify if:

• Patients presented with bilateral, well-formed mandibular distal extension residual ridges covered by keratinized mucosa, with a minimum thickness of 1.5-3 mm .
• Each participant had a sound first or second premolar serving as the terminal abutment, with a crown-to-root ratio of ≥ 1:2.
• Comprised fully or partially dentate maxillary arches, an Angle Class I molar relationship, and adequate interarch space (7-8 mm) to accommodate the prosthesis .

You may not qualify if:

• The presence of systemic conditions affecting bone metabolism or healing
• pathological conditions in the edentulous area (e.g., residual cysts, retained roots, or severe ridge re-sorption);
• parafunctional habits such as bruxism, clenching, or tongue thrusting
• pro-nounced anatomical undercuts in the lingual mandible or adjacent to abutment teeth that could impede denture fabrication or insertion.

Sponsors & Collaborators

• Tanta University: lead

Study Sites (1)

Tanta University

Tanta, Egypt

Location

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: NONE
• Masking Details: Masking Description
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Lecturer

Model Details: Model Description

Study Record Dates

• First Submitted: May 1, 2026
• First Posted: May 13, 2026
• Study Start: May 30, 2021
• Primary Completion: November 30, 2024
• Study Completion: November 30, 2024
• Last Updated: May 13, 2026

Record last verified: 2021-05

Locations

EG (1)