The global increase in the aging population has led to a rise in total edentulism, which remains a major public health concern. two-implant-retained mandibular overdentures have been regarded as the standard of care, offering superior retention, stability, comfort, and masticatory efficiency compared to conventional dentures. Among available attachment systems-bar, ball, stud, and magnet-the Equator attachment has gained popularity due to its low vertical profile, suitability for limited inter-occlusal space, and ease of handling. Assessment of masticatory performance and occlusal balance can be objectively measured using devices such as bite force analyzers and the computerized T-Scan system, which quantifies occlusion and disocclusion times. Conventional heat-cured polymethyl methacrylate (PMMA) remains the most widely used denture base material; however, it has mechanical and biological limitations. Flexible denture base materials have been introduced to overcome these drawbacks by enhancing adaptation, distributing occlusal loads more evenly, and improving comfort and retention.
24 Patients will be randomly and equally divided into two treatment groups: 1. Group 1: Each patient in this group will receive conventional maxillary and mandibular complete dentures made of heat-cured acrylic resin PMMA. In the mandible, two implants were inserted in the symphyseal area and retained by equator attachments. 2. Group 2: Patients in this group received the same type of treatment as the patients in group 1, but the mandibular overdentures were made of the flexible acrylic resin "breflex" The present study will be performed to compare the difference in retention, occlusal force distribution, occlusion and disocclusion time, and bite force for implant retained mandibular over denture using PMMA and flexible dentures base materials
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
DOUBLE
Enrollment
24
Mandibular complete dentures made of heat-cured acrylic resin (PMMA). In the mandible, two implants were inserted in the symphyseal area and retained by Equator attachments.
Mandibular overdentures were made of the flexible acrylic resin breflex, In the mandible, two implants were inserted in the symphyseal area and retained by Equator attachments
Cairo University
Cairo, Egypt
Occlusal force distribution
Occlusal force distribution will be measured by T-Scan, The latest version (T-Scan III) provides a dynamic visual evaluation of a patient's occlusion from initial tooth contact to maximum intercuspation. The system records relative force values and allows objective quantitative evaluation of occlusal balance by recording numerical values for occlusion and disocclusion times
Time frame: Follow up visits were scheduled at denture insertion, 6, and 12 months
Retention of lower denture
Retention of lower denture will be measured using digital force gauge, Retention will be measured using digital force gauge A digital force meter was used to measure denture resistance to vertical displacement (i.e., retention) by applying a pulling force on a metal hook located in the geometric center of each mandibular conventional denture that was identified on the lower cast at the intersection of three lines bisecting the angles of the triangle, formed by both retromolar pads and the midline. Measurement of mandibular denture retention: The patient was instructed to place his head on chin rest and occlusal plane was set parallel to the floor. Tongue freedom was checked then and three minutes seating time was allowed before taking the measurements. A vertical pulling force was applied using the metallic probe of the digital force-meter that was attached to the hook present at the geometric center of mandibular denture. Average value of six readings was recorded.
Time frame: Follow up visits were scheduled at denture insertion, 6, and 12 months
occlusion time
occlusion and disocclusion time will be measured by T-Scan, The latest version (T-Scan III) provides a dynamic visual evaluation of a patient's occlusion from initial tooth contact to maximum intercuspation. The system records relative force values and allows objective quantitative evaluation of occlusal balance by recording numerical values for occlusion times
Time frame: Follow up visits were scheduled at denture insertion, 6, and 12 months
Biting force
Biting force will be measured by bite force meter
Time frame: Follow up visits were scheduled at denture insertion, 6, and 12 months
Disocclusion time
will be measured by T-Scan, The latest version (T-Scan III) provides a dynamic visual evaluation of a patient's occlusion from initial tooth contact to maximum intercuspation. The system records relative force values and allows objective quantitative evaluation of occlusal balance by recording numerical values for disocclusion times
Time frame: Follow up visits were scheduled at denture insertion, 6, and 12 months
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