Facebow and Articulators Chapter PDF 2024/2025

PRECLINICAL REMOVABLE COMPLETE PROSTHODONTICS COURSE FACEBOW AND ARTICULATORS Removable Complete Prosthodontics  2024/2025 MAXILLARY FACEBOW 1  2024/2025 It is a caliper-like device that is used t...

PRECLINICAL REMOVABLE COMPLETE PROSTHODONTICS COURSE FACEBOW AND ARTICULATORS Removable Complete Prosthodontics  2024/2025 MAXILLARY FACEBOW 1  2024/2025 It is a caliper-like device that is used to record the relationship of the jaws to the tempromandibular joint or (opening axis of the jaws) and to orient the casts in this same relationship to the opening axis of the articulator (terminal hinge axis). 2  2024/2025 The face-bow transfer ensures that the casts are mounted centrally in correct relation to the inter- condylar axis and to the centers of lateral movements. 3  2024/2025 METHODS OF DETERMINATION OF TERMINAL HINGE AXIS DETERMINATION 4  2024/2025 Mandibular or kinematic face-bow (hinge axis face-bow). This locates the exact axis of rotation of the condyles. 5  2024/2025 Arbitrary method (11-12 mm) in front the tragus of the ear on an Imaginary line between the outer canthus of the eye and the upper surface of the tragus of the ear. 6  2024/2025 Mandibular Maxillary “A device used to locate “A device used to record the terminal hinge or the the relation between the condylar axis.” maxilla and the TMJ and to transfer this relation to the articulator.” 7  2024/2025 FUNCTIONS 8  2024/2025 1. Recording Spatial Relationship: The primary function of a facebow is to record the spatial relationship between the upper jaw and the TMJ. This information is important for accurately reproducing the patient's occlusal relationship in the dental laboratory. 9  2024/2025 2. Replicating Natural Jaw Movement: Facebows help replicate the natural movements of the patient's jaw, allowing for the creation of dental restorations that harmonize with the individual's unique occlusion and jaw dynamics. 10  2024/2025 COMPONENTS 11  2024/2025 1. The U-shaped frame is designed to fit around the patient's head. It serves as the main structure of the facebow, providing stability during the recording process. 12  2024/2025 2. Transfer Assembly: The transfer assembly is a part of the facebow that attaches to the patient's maxillary teeth. It is responsible for capturing the spatial relationship of the upper jaw. This component often includes a fork or bite fork that holds the upper dental arch securely. 13  2024/2025 3. Earpieces or Ear Bows: Some facebows use earpieces or ear bows to secure the facebow to the patient's head. These can be adjustable to accommodate variations in anatomy. 14  2024/2025 4. Anterior Reference Points: These are points or markers on the facebow that provide references for the orientation of the maxillary arch in relation to the TMJ. They may include midline indicators and other reference points to establish proper alignment. 15  2024/2025 5. Locking Mechanisms: Facebows often include locking mechanisms or adjustments to secure the facebow in the desired position and prevent movement during the recording process. 16  2024/2025 REFERENCE POINTS 17  2024/2025 External Auditory Meatus (Ear Canal) Purpose: The facebow has earpieces that fit into the patient’s external auditory meatus. This point serves as a reference for the hinge axis of the jaw, which is crucial for mounting the upper cast on the articulator to simulate the jaw’s opening and closing motion. Significance: It approximates the location of the mandibular condyle in the temporomandibular joint (TMJ). 18  2024/2025 Nasion (Nasion Point) Purpose: The nasion point is located at the bridge of the nose, where the frontal and nasal bones meet. Many facebows have a nasion support that rests here, helping stabilize the facebow. Significance: This point helps ensure the vertical alignment of the facebow in relation to the patient’s facial anatomy. 19  2024/2025 Maxillary bone (Bite Fork) Purpose: The bite fork is placed in the patient’s mouth and positioned against the maxillary bone. The patient bites down on the fork, which is then attached to the facebow. Significance: This records the position of the maxillary arch in relation to the rest of the head, which is critical for accurate transfer to the articulator. 20  2024/2025 DENTAL ARTICULATORS 21  2024/2025 An articulator is a mechanical instrument that represents the temporomandibular joints and jaws, to which maxillary and mandibular casts may be attached to simulate some or all mandibular movements. 22  2024/2025 FUNCTIONS 23  2024/2025 1. Replicating Maxillary Position: They also replicate the position of the upper jaw (maxilla), ensuring that dental restorations, such as crowns or bridges, are designed to fit harmoniously within the mouth. 24  2024/2025 2. Simulating Mandibular Movements: Dental articulators allow for the reproduction of the movements of the lower jaw (mandible). This is important for creating dental prosthetics and restorations that accurately represent natural jaw functions. 25  2024/2025 3. Positioning Dental Models: Dentists use articulators to mount dental casts or models. This helps in studying the occlusion (bite) and designing dental prosthetics that fit the patient's specific oral anatomy. 26  2024/2025 4. The articulator provides a stable base for studying the relationships between the upper and lower dental arches, allowing for accurate adjustments to achieve an optimal occlusion. 27  2024/2025 5. Testing Occlusal Contacts: Dental articulators assist in evaluating the occlusal contacts between upper and lower teeth. This is important for ensuring a balanced bite, preventing issues such as premature wear or discomfort. 28  2024/2025 6. Designing Treatment Options: Articulators aid in visualizing different treatment options by allowing dentists to study the dynamic relationship between upper and lower teeth. 29  2024/2025 7. Communication with Laboratories: Dental articulators provide a standardized way to communicate the patient's occlusal details and jaw movements to dental laboratories, ensuring that the fabricated restorations meet the patient's specific needs. 30  2024/2025 COMPONENTS 31 2024/2025 32 2024/2025 33  2024/2025 Class I Class II Class III Class IV Non Fixed Semi Fully Other Names Adjustable Condylar Adjustable Adjustable Articulator. Path Articulator Articulator Simple Articulator. Hinge Articulator. 34  2024/2025 Class I Class II Class III Class IV Opening. Opening. Opening. Opening. Closing. Closing. Closing. Closing. Movements Protrusive Protrusive Protrusive (Fixed). (Adjustable). (Adjustable). Lateral Lateral (Calculated). (Adjustable). 35  2024/2025 Class I Class II Class III Class IV Upper and Upper and Same as class Same as class lower lower members II except III except members joined by two Horizontal Horizontal Components joined by joints (Protrusive) (Protrusive) simple representing Condylar path and Lateral hinge with TMJ. Horizontal is adjustable. Condylar path screw and (Protrusive) is adjustable. metal plate Condylar path is acting as fixed 30○. vertical stop. 36  2024/2025 Class I Class II Class III Class IV Centric Occluding Face-bow Record (If Face-bow Record to Face-bow Record to Relation to mount Needed) to mount the mount the upper cast. mount the upper cast. the lower cast. upper cast, or by Bonwill Δ. Centric Occluding Centric Occluding Centric Occluding Relation Relation to mount the Relation to mount the to mount the lower cast. lower cast. lower cast. Protrusive Record. Protrusive Record to Protrusive Record to adjust Horizontal adjust Horizontal Records Condylar Path. Condylar Path. Lateral Record Right Lateral Record to calculated by Hanau`s adjust Right Lateral Formula Condylar Path. 𝑯 Left Lateral Record to 𝑳 = + 𝟏𝟐 𝟖 adjust Left Lateral L = Lateral condylar Condylar Path. Path. H = Horizontal (Protrusive Condylar Path) 37 2024/2025 38 2024/2025 39 2024/2025 40 2024/2025 41 2024/2025 42 2024/2025 43 2024/2025 44 2024/2025 45 2024/2025 46 2024/2025 47 2024/2025 48 2024/2025 49 2024/2025 50 FACEBOW AND ARTICULATORS PRECLINICAL REMOVABLE COMPLETE PROSTHODONTICS  FACEBOW AND ARTICULATORS 2024/2025 MAXILLARY FACEBOW Definition: It is a caliper-like device that is used to record the relationship of the jaws to the tempromandibular joint or (opening axis of the jaws) and to orient the casts in this same relationship to the opening axis of the articulator (terminal hinge axis). The face-bow transfer ensures that the casts are mounted centrally in correct relation to the inter-condylar axis and to the centers of lateral movements. Mandibular or kinematic Arbitrary method (11-13 face-bow (hinge axis face- mm) in front the tragus of the bow). This locates the exact ear on an Imaginary line axis of rotation of the between the outer canthus of condyles. the eye and the upper surface of the tragus of the ear. Referenced by: Iwao Hayakawa's Principles and Practices of Complete Dentures, Recording jaw relations., P; 50 1  FACEBOW AND ARTICULATORS 2024/2025 Mandibular facebow Maxillary facebow “A device used to record the “A device used to locate the relation between the maxilla terminal hinge or the and the TMJ and to transfer condylar axis.” this relation to the articulator.” Functions of facebow: 1. Recording Spatial Relationship: The primary function of a facebow is to record the spatial relationship between the upper jaw and the TMJ. This information is important for accurately reproducing the patient's occlusal relationship in the dental laboratory. 2. Replicating Natural Jaw Movement: Facebows help replicate the natural movements of the patient's jaw, allowing for the creation of dental restorations that harmonize with the individual's unique occlusion and jaw dynamics. Components of facebow: 1. The U-shaped frame is designed to fit around the patient's head. It serves as the main structure of the facebow, providing stability during the recording process. 2. Transfer Assembly: The transfer assembly is a part of the facebow that attaches to the patient's maxillary teeth. It is responsible for capturing the spatial relationship of the upper jaw. This component often includes a fork or bite fork that holds the upper dental arch securely. 3. Earpieces or Ear Bows: Some facebows use earpieces or ear bows to secure the facebow to the patient's head. These can be adjustable to accommodate variations in anatomy. Referenced by: Iwao Hayakawa's Principles and Practices of Complete Dentures, Recording jaw relations., P; 50 2  FACEBOW AND ARTICULATORS 2024/2025 4. Anterior Reference Points: These are points or markers on the facebow that provide references for the orientation of the maxillary arch in relation to the TMJ. They may include midline indicators and other reference points to establish proper alignment. 5. Locking Mechanisms: Facebows often include locking mechanisms or adjustments to secure the facebow in the desired position and prevent movement during the recording process. Facebow reference points: 1. External Auditory Meatus (Ear Canal) Purpose: The facebow has earpieces that fit into the patient’s external auditory meatus. This point serves as a reference for the hinge axis of the jaw, which is crucial for mounting the upper cast on the articulator to simulate the jaw’s opening and closing motion. Significance: It approximates the location of the mandibular condyle in the temporomandibular joint (TMJ). 2. Nasion (Nasion Point) Purpose: The nasion point is located at the bridge of the nose, where the frontal and nasal bones meet. Many facebows have a nasion support that rests here, helping stabilize the facebow. Significance: This point helps ensure the vertical alignment of the facebow in relation to the patient’s facial anatomy. 3. Maxillary bone (Bite Fork) Referenced by: Iwao Hayakawa's Principles and Practices of Complete Dentures, Recording jaw relations., P; 50 3  FACEBOW AND ARTICULATORS 2024/2025 Purpose: The bite fork is placed in the patient’s mouth and positioned against the maxillary bone. The patient bites down on the fork, which is then attached to the facebow. Significance: This records the position of the maxillary arch in relation to the rest of the head, which is critical for accurate transfer to the articulator. DENTAL ARTICULATORS Definition: An articulator is a mechanical instrument that represents the temporomandibular joints and jaws, to which maxillary and mandibular casts may be attached to simulate some or all mandibular movements. Functions: 1. Replicating Maxillary Position: They also replicate the position of the upper jaw (maxilla), ensuring that dental restorations, such as crowns or bridges, are designed to fit harmoniously within the mouth. 2. Simulating Mandibular Movements: Dental articulators allow for the reproduction of the movements of the lower jaw (mandible). This is important for creating dental prosthetics and restorations that accurately represent natural jaw functions. 3. Positioning Dental Models: Dentists use articulators to mount dental casts or models. This helps in studying the occlusion (bite) and designing dental prosthetics that fit the patient's specific oral anatomy. Referenced by: Iwao Hayakawa's Principles and Practices of Complete Dentures, Recording jaw relations., P; 50 4  FACEBOW AND ARTICULATORS 2024/2025 4. The articulator provides a stable base for studying the relationships between the upper and lower dental arches, allowing for accurate adjustments to achieve an optimal occlusion. 5. Testing Occlusal Contacts: Dental articulators assist in evaluating the occlusal contacts between upper and lower teeth. This is important for ensuring a balanced bite, preventing issues such as premature wear or discomfort. 6. Designing Treatment Options: Articulators aid in visualizing different treatment options by allowing dentists to study the dynamic relationship between upper and lower teeth. 7. Communication with Laboratories: Dental articulators provide a standardized way to communicate the patient's occlusal details and jaw movements to dental laboratories, ensuring that the fabricated restorations meet the patient's specific needs. Referenced by: Iwao Hayakawa's Principles and Practices of Complete Dentures, Recording jaw relations., P; 50 5  Class I Class II Class III Class IV Other Names Non Adjustable Articulator. Fixed Condylar Path Articulator. Semi Adjustable Articulator Fully Adjustable Articulator Simple Hinge Articulator. Components Same as class III except Upper and lower members joined by Upper and lower members joined by two Same as class II except Horizontal (Protrusive) and simple hinge with screw and metal joints representing TMJ. Horizontal Horizontal (Protrusive) Lateral Condylar path is plate acting as vertical stop. (Protrusive) Condylar path is fixed 30○. Condylar path is adjustable. adjustable. Movements Opening. Opening. Opening. Opening. Closing. Closing. Closing. Closing. Protrusive (Adjustable). Protrusive (Adjustable). Protrusive (Fixed). Lateral (Calculated). Lateral (Adjustable). Face-bow Record to mount the Face-bow Record to mount upper cast. the upper cast. Centric Occluding Relation to Centric Occluding Relation mount the lower cast. to mount the lower cast. Protrusive Record to adjust Face-bow Record (If Needed) to mount the Protrusive Record to adjust Horizontal Condylar Path. Records upper cast, or by Bonwill Δ. Horizontal Condylar Path. Centric Occluding Relation to mount Lateral Record calculated by Centric Occluding Relation to mount the Right Lateral Record to the lower cast. Hanau`s Formula lower cast. adjust Right Lateral 𝑯 Protrusive Record. 𝑳 = + 𝟏𝟐 Condylar Path. 𝟖 Left Lateral Record to adjust Left Lateral Condylar L = Lateral condylar Path. Path. H = Horizontal (Protrusive Condylar Path)