Prosthodontics Diagnosis Quiz

Diagnostic Casts

• Diagnostic casts are three-dimensional replicas of a patient's teeth and surrounding structures.
• They provide information about tooth relationships not easily observable intraorally.
• Used for comprehensive examination of tooth relationships, diagnosis, and treatment planning.
• They are essential in fixed prosthodontics.

Evaluating Edentulous Spaces

• Measure the occlusocervical dimension of edentulous spaces.
• Assess spatial relationships with adjacent and opposing teeth.
• Evaluate soft tissue contours and their affect on emergence profile planning.

Assessing Abutment Teeth

• Alignment: Relative alignment of abutment teeth impacts prosthesis design.
• Angulation: Angulation affects path of insertion and retention of the prosthesis.
• Tooth Position: Analyze subtle changes in individual tooth position.
• Structural Integrity: Examine structural integrity of abutment teeth.

Diagnostic Procedures

• Simulation of tooth preparations on duplicate casts, refining techniques before intraoral procedures.
• Diagnostic wax-up, visualizing and evaluating proposed treatment outcomes.
• Detailed occlusal analysis to identify potential interferences and harmonize occlusion.

Advantages of Diagnostic Casts

• Visibility: Provide unobstructed 360° view compared to limited intraoral examination.
• Patient Reflexes: Absent, allowing unrestricted analysis time.
• Reproducibility: Easily reproducible, unlike intraoral examinations.

Impression Making for Diagnostic Casts

• Accuracy is crucial; even small flaws can lead to inaccuracies.
• Proper technique and material selection are key.

Importance of Accuracy

• Void Prevention: Small voids can create nodules on occlusal surfaces, causing inaccurate articulator mounting.
• Border Extension: Impressions should extend beyond cervical line to aid in accurate mounting.
• Material Selection: Irreversible hydrocolloid is suitable for planning but not for definitive casts.

Irreversible Hydrocolloid

• Contains sodium or potassium salts of alginate acid and water-soluble ingredients.
• Forms insoluble calcium alginate upon reacting with calcium sulfate.
• Includes trisodium phosphate to regulate setting rate.

Impression Material Behavior

• Imbibition: Absorption of liquid from the environment, causing distortion.
• Syneresis: Giving off liquid to the environment, causing distortion.
• Pouring Time: Impressions must be poured immediately to prevent distortion.

Tray Considerations

• Retention: Adhesive, perforations, or undercuts help retain impression material.
• Size: Larger trays accommodate more material, enhancing accuracy.
• Support: Ensure full tray support to prevent impression distortion.

Diagnostic Impression Technique

• Tray Selection: Choose the largest tray that fits comfortably.
• Material Preparation: Mix irreversible hydrocolloid to a homogenous consistency.
• Impression Taking: Load tray, wipe material into crevices, and seat it in the patient's mouth.
• Removal and Disinfection: Remove quickly after gelation, rinse, and disinfect the impression.

Impression Taking Process

• Preparation: Clean teeth and rinse patient's mouth thoroughly.
• Material Application: Load tray, wipe material into occlusal crevices.
• Tray Seating: Carefully insert tray, reminding patient to relax cheek muscles.
• Removal: Remove quickly 2-3 minutes after gelation.

Disinfection and Pouring

• Disinfection: Spray with glutaraldehyde and seal in a 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 a 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 and repeat the process.

Transferring Casts to Articulators

• Facebow Transfer: Use a facebow to transfer the maxillary cast, ensuring accurate spatial orientation.
• Centric Relation Record: Use a record to articulate the mandibular cast, ensuring accurate jaw relationship.
• Condylar Element Setting: Set condylar elements using protrusive and excursive interocclusal records.

Analyzing Occlusal Relationships

• Centric Relation: Mandible in its most upward, backward, and unstrained position.
• Maximum Intercuspation: The position of maximum interdigitation of cusps in a closed jaw position.
• Mandibular Movements: Analyze occlusal contacts throughout the range of mandibular movements.

Occlusal Plane Analysis

• Anterior Guidance: Evaluate influence of anterior guidance on posterior disclusion.
• Group Function: Simultaneous contact of multiple posterior teeth on the working side during lateral jaw movements.

Articulator Selection for Dental Prostheses

• Articulators are mechanical devices that simulate mandibular movement.
• Proper selection can impact treatment outcomes and efficiency.

Types of Articulators

• Small Nonadjustable: Limited capacity, may lead to occlusal discrepancies.
• Semiadjustable: Practical, provides necessary diagnostic information with minimal adjustments.
• Fully Adjustable: Large capacity, can follow patient's border movements accurately.

Small Nonadjustable Articulators

• Limited Accuracy: Cannot reproduce full range of mandibular movement.
• Occlusal Discrepancies: May lead to restorations with interferences.
• Hinge Closure Issues: Distance between hinge and tooth is different from 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.
• Time-Efficient: Does not require excessive time or expertise.

Arcon vs Nonarcon Designs

• Arcon Design: Condylar spheres on lower component, anatomically "correct" design.
• Nonarcon Design: Upper and lower members rigidly attached, popular in complete denture prosthodontics.
• Movement Simulation: Arcon movements are easier to understand; Nonarcon movements are "backwards"

Semiadjustable Articulator

• Adjustments:
  • Condylar Inclination: Adjusts to mimic patient's condylar path.
  • Progressive Side Shift: Simulates lateral movement of mandible.
  • Immediate Side Shift: Replicates initial lateral movement of condyle.

Interocclusal Records

• Materials used to transfer jaw relationship from patient's mouth to an articulator.
• Wax: Used to adjust mechanical fossae.
• Other suitable materials: Various materials can mimic mandibular movements.

Fully Adjustable Articulators

• High Accuracy: Can follow patient's border movements precisely.
• Complex Use: Requires high skill level and understanding.
• Pantographic Tracings: Used instead of wax records for adjustment.

Advantages of Fully Adjustable Articulators

• Precise Replication: Track irregular mandibular movement pathways.
• Complex Prostheses: Enable fabrication of intricate dental work.
• Minimal Adjustments: Reduces chairside time for complex cases.

Choosing the Right Articulator

• Treatment Complexity: Consider type and complexity of treatment needs.
• Accuracy Requirements: Evaluate the demands for procedural accuracy.
• Time Efficiency: Evaluate potential for time savings.
• Skill Level: Consider expertise of dentist and technician.

Test your knowledge on diagnostic casts, evaluating edentulous spaces, and assessing abutment teeth in prosthodontics. This quiz covers essential concepts for comprehensive treatment planning and diagnosis. Perfect for dental professionals and students alike!