Diagnostic Casts and Related Procedures PDF

Diagnostic Casts and Related Procedures Dr. Wayel Mohammed Huraib Fixed Prosthodontics I Prosthodontics Division Dentistry Program What is the Diagnostic Diagnostic Casts ? A dental diagnostic cast, also known as a study model or diagnostic model, is a detailed, three dimensional replica of a pat...

Diagnostic Casts and Related Procedures Dr. Wayel Mohammed Huraib Fixed Prosthodontics I Prosthodontics Division Dentistry Program What is the Diagnostic Diagnostic Casts ? A dental diagnostic cast, also known as a study model or diagnostic model, is a detailed, three dimensional replica of a patient's teeth and surrounding oral structures. It is typically made from a dental impression using materials like dental stone or plaster. Diagnostic Casts in Fixed Prosthodontics Prosthodontics Diagnostic casts are crucial in fixed prosthodontic treatment planning. They allow for comprehensive examination of static and dynamic tooth relationships. These casts provide insights not easily observable intraorally. They are essential for accurate diagnosis and treatment planning. Evaluating Edentulous Spaces 1 Occlusocervical 2 Spatial Relationships 3 Soft Tissue Contours Dimension Measure the Assess spatial Evaluate soft tissue occlusocervical relationships with contours in edentulous dimension of adjacent and opposing areas. This affects edentulous spaces. This teeth. Consider emergence profile is crucial for prosthesis implications for planning. planning. prosthesis design. Assessing Abutment Teeth Alignment Evaluate the relative alignment of proposed abutment teeth. Consider impact on prosthesis design. Angulation Assess angulation of abutment teeth. This affects path of insertion and retention. Tooth Position Analyze subtle changes in individual tooth position. Note any drifting or rotation. Structural Integrity Examine structural integrity of abutment teeth. Consider need for additional restorative work. Diagnostic Procedures Tooth Preparation Simulation Practice tooth preparations on duplicate casts. Refine techniques before intraoral procedure. Diagnostic Wax-up Perform diagnostic wax-up procedures. Visualize and evaluate proposed treatment outcomes. Occlusal Analysis Conduct detailed occlusal analysis. Identify potential interferences and harmonize occlusion. Advantages of Diagnostic Casts Casts Aspect Intraoral Diagnostic Casts Examination Visibility Limited by oral Unobstructed cavity 360° view Patient Reflexes Present Absent Time Constraints Often limited Unrestricted analysis time Reproducibility Challenging Easily reproducible Impression Making for Diagnostic Casts Accurate dental impressions are crucial for creating diagnostic casts. Even small flaws can lead to significant inaccuracies. Proper technique and material selection are essential for successful outcomes. Importance of Accuracy Void Prevention Border Extension Material Selection Small voids can create Impressions should extend Irreversible hydrocolloid is nodules on occlusal several millimeters beyond suitable for planning but surfaces, leading to the cervical line of teeth. not for definitive casts. inaccurate articulator mounting. Irreversible Hydrocolloid Composition 1 Main Components Sodium or potassium salts of alginic acid, water-soluble. 2 Chemical Reaction Forms insoluble calcium alginate when reacting with calcium sulfate. 3 Additional Ingredients Trisodium phosphate to control setting rate. Impression Material Behavior Imbibition Syneresis Pouring Time Alginate absorbs liquid from Alginate gives off liquid to the Impressions must be poured the atmosphere, causing atmosphere, also causing immediately to prevent distortion. distortion. distortion. Tray Considerations Retention Use adhesive, perforations, or undercuts for material retention. Size Larger trays allow for more material, improving accuracy. Support Ensure full tray support to prevent impression distortion. Diagnostic Impression Technique 1 Tray Selection Choose the largest tray that fits comfortably in the patient's mouth. 2 Material Preparation Mix irreversible hydrocolloid to a homogenous consistency. 3 Impression Taking Load tray, wipe material into crevices, and seat in patient's mouth. 4 Removal and Disinfection Remove quickly after gelation, rinse, and disinfect the impression. Impression Taking Process Preparation 1 Clean teeth and rinse mouth thoroughly. Material Application 2 Load tray and wipe material into occlusal crevices. Tray Seating 3 Insert tray and remind patient to relax cheek muscles. 4 Removal Remove quickly 2-3 minutes after gelation. Faunally Evaluate your Alginate impression Smooth Surface ? Rounded periphery ? No oral cavity debris Disinfection and Pouring Disinfection Spray with glutaraldehyde and place in sealed bag for 10 minutes. Timing Pour within 15 minutes of removal for accuracy. Stone Selection Use vacuum-mixed ADA type IV or V stone. Cast Storage and Separation Storage Position Tray side down Environment Covered with wet paper in humidor Duration 1 hour Separation Time 1 hour after pouring Diagnostic Cast Quality Evaluation Accuracy Check Examine for voids, nodules, and proper articulation. Surface Detail Ensure adequate reproduction of dental structures. Repeat if Necessary Discard questionable impressions and casts, then repeat the process. Transferring Casts to Articulators Articulators 1 Facebow Transfer Use a facebow to transfer the maxillary cast. This ensures accurate spatial orientation. 2 Centric Relation Record Utilize a centric relation interocclusal record for mandibular cast articulation. Condylar Element Setting 3 Set condylar elements using protrusive and excursive interocclusal records. Analyzing Occlusal Relationships Centric Relation Maximum Intercuspation The position of the mandible in relation to The occlusal relationship where the cusps the maxilla where the condyles are in of the upper and lower teeth interdigitate their most upward, backward, and maximally when the jaws are closed in unstrained position within the glenoid their habitual position. fossae Analyzing Occlusal Relationships Centric Relation Maximum Intercuspation Mandibular Movements Assess the centric relation Examine the maximum Analyze occlusal contacts position. Evaluate any intercuspation position. Note throughout the range of discrepancies between CR any slides from CR to MI. mandibular movements. and MI. Occlusal Plane Analysis Anterior Guidance Evaluate anterior guidance and its influence on posterior disclusion. Group function Its an occlusal arrangement where multiple posterior teeth on the working side (the side towards which the jaw moves during lateral excursion) come into contact simultaneously during lateral jaw movements. Articulator Selection Selection for Dental Prostheses Articulators are mechanical devices that simulate mandibular movement. They are crucial for analyzing functional relationships in dental prosthetics. Proper articulator selection can significantly impact treatment outcomes and efficiency. Types of Articulators Small Nonadjustable Semiadjustable Fully Adjustable Limited capacity to Practical for routine fixed Wide range of positions. Can reproduce mandibular prostheses. Provides follow patient's border movement. Can lead to necessary diagnostic movements accurately. occlusal discrepancies. information with minimal adjustments. preencoded.png Small Nonadjustable Articulators 1 Limited Accuracy Cannot reproduce full range of mandibular movement. 2 Occlusal Discrepancies May lead to restorations with occlusal interferences. 3 Hinge Closure Issues Distance between hinge and tooth is less than in patients. Semiadjustable Articulators Practical Approach Suitable for most routine fixed prostheses. Minimal Adjustments Reduces need for clinical adjustments during treatment. Anatomical Accuracy Size similar to anatomic structures they represent. Time-Efficient Does not require excessive time or expertise to use. Arcon vs Nonarcon Designs Arcon Design 1 Condylar spheres on lower component. Anatomically "correct" design. 2 Nonarcon Design Popular in complete denture prosthodontics. Rigidly attached upper and lower members. Movement Simulation 3 Arcon easier to understand. Nonarcon movements are "backwards". preencoded.png Semiadjustable Articulator Adjustments Condylar Inclination Adjusts to mimic patient's condylar path. Progressive Side Shift Simulates lateral movement of the mandible. Immediate Side Shift Replicates initial lateral movement of the condyle. Interocclusal Records To transform the relation between the upper & lower dental arch from the patient mouth to the articulator. Material Thickness Purpose Adjust Wax Several mm mechanical fossae Mimic patient Other suitable Varies mandibular materials movements Fully Adjustable Articulators High Accuracy Complex Use Pantographic Tracings Can follow patient's border Requires high skill level and Used instead of wax records movements precisely. understanding. for adjustment. Advantages of Fully Adjustable Adjustable Articulators 1 Precise Replication Can track irregular pathways of movement throughout entire trajectories. 2 Complex Prostheses Enables fabrication of intricate dental work. 3 Minimal Adjustments Reduces chairside time for complex cases. Choosing the Right Articulator Treatment Complexity Consider the type and complexity of treatment needs. Accuracy Requirements Assess the demands for procedural accuracy. Time Efficiency Evaluate the potential for time savings in subsequent treatment stages. Skill Level Consider the expertise of the dentist and technician. Reference Chapter 2 Page 42 Treatment Complexity Consider the type and complexity of treatment needs. Accuracy Requirements Assess the demands for procedural accuracy. Time Efficiency Evaluate the potential for time savings in subsequent treatment stages..