Maxillomandibular Relations Short Essays

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Maxillomandibular Relations Short Essays

Question 1. Define face bow. Explain the parts of the face bow
Answer:

Definition Of Face Bow:

A caliper like device is used to record the relationship of the jaws to the temporomandibular joints & to orient the casts on the articulator to the relationship of the opening axis of the temporomandibular joint

Parts Of Face Bow:

1. U-Shaped Frame:

  • Fce bow is a U-shaped metallic bar that forms the main frame of the face bow
  • All other components are attached to it
  • Face bow records the plane of the cranium

Read And Learn More: Prosthodontics Question And Answers

2. Condylar Rods:

  • Condylar rods are two small metallic rods on either side of the free end of the U-shaped frame
  • Helps to locate the hinge axis
  • Transfer the hinge axis of the TMJ by attaching to the condylar shaft in the articulator

3. Bite Fork:

Bite Fork is U shaped plate that is attached to the occlusal rims while recording the orientation relation It is attached to the frame with the help of stem

Bite Fork should be inserted about 3 mm below the occlusal surface within the occlusal rim

4. Locking Device:

  • The locking Device helps to attach the bite fork to the U-shaped frame
  • The locking Device supports the face bow, and occlusal rim, and is cast during articulation
  • The locking Device consists of a transfer rod and a transverse rod The U-shaped frame is attached to the vertical transfer rod
  • A transverse rod connects the transfer rod with the stem of the bite fork

5. Orbital Pointer:

  • Orbital Pointer marks the anterior reference point
  • Present only in the arbitrary face bow

Question 2. Balanced Occlusion.
Answer:

Balanced Occlusion Definition:

“The simultaneous compacting of the maxillary & mandibular teeth on the right & left & in the anterior & posterior occlusal areas in centric & eccentric positions, developed to lessen or limit tipping or rotating of the denture bases in relation to the supporting structures”.

Types Of Balanced Occlusion:

  • Unilateral balanced occlusion
  • Bilateral balanced occlusion
  • Protrusive balanced occlusion
  • Lateral balanced occlusion

Laws Of Balanced Articulation:

  • Condylar guidance
  • Incisal guidance
  • Compensatory curves
  • Relative cusp height
  • Plane of the orientation of the occlusal plane

Factors Influencing Balanced Occlusion:

  • Condylar guidance
  • Incisal guidance
  • Orientation of occlusal plane
  • Cuspal angulation
  • Compensatory curves

How Balance Is Achieved:

  • The incisal and condylar guidance produce an increase in posterior separation
    While other three factors i.e., occlusal plane, caspal angulation, and compensatory curves cause a decrease in posterior separation.
  • The effect of incisal and condylar guidance should counteract the other three factors to obtain a balanced occlusion

Question 3. Unbalanced occlusion.
Answer:

Unbalanced Occlusion is an arrangement Of teeth With a Form or purpose

Unbalanced Occlusion General Considerations:

  • Opposing artificial teeth should not contact in eccentric relation
  • Tooth contact should occur only when the mandible is in centric occlusion
  • Repeat the mandibular movements till the comfort of the patient in centric relation

Unbalanced Occlusion Concepts:

1. Pound’s Concept:

  • Proposed importance of phonetics & aesthetics for anterior teeth
  • While posterior teeth should have a sharp upper lingual cusp & wide lower central fossa
  • Lingualized occlusion
  • A triangle formed between the mesial end of the canine & the two sides of the retromolar pad

Maxillomandibular Relations Pounds Concept Of Tooth Arrangement

2. Hardy’s Concept: Proposed flat occlusal plane with non-anatomical teeth for complete denture

3. Kurth’s Concept: Flat posterior teeth in a horizontal plane without any balancing ramps It is an arrangement of teeth with form or purpose

Maxillomandibular Relations Philip M Jones Concept Of Non Balanced Occlusion

Question 4. Orientation relation in the complete denture And Write Face bow
Answer:

Orientation Jaw Relation:

  • “The jaw relation when the mandible is kept in its most posterior position, it can rotate in the sagittal plane around an imaginary transverse axis passing through or near the condyles”.
  • It can be recorded with the help of a face bow

Face Bow:

A caliper-like device that is used to record the relationship of the jaws to the temporomandibular joints & to orient the casts on the articulator to the relationship of the opening axis of the temporomandibular joint

Face Bow Parts:

  • U shaped frame
  • Condylar rods
  • Bite fork
  • Locking device
  • Orbital pointer

Face Bow Types:

  1. Arbitrary Face Bow:
    • Facia type
    • Earpiece type
    • Hanau face bow
    • Systematic
    • Twirl bow
    • Whipmix
  2. Kinematic Face Bow:

Maxillomandibular Relations U Shaped Frame of A Face Bow

Maxillomandibular Relations Orbital Pointer

  • Aluwax is softened
  • The bite fork is embedded into this wax A thin layer of petroleum jelly is applied over both the rims
  • Both the rims are inserted into the patient’s mouth
  • The bite fork is also inserted into the patient’s mouth Ask the patient to close the mouth
  • The stem of the bite fork is locked to the transverse rod
  • The orbital pointer is made to touch the infraorbital notch
  • The entire face bow along with the rims is removed and articulated

Maxillomandibular Relations Face Bow Along With Rims Removed And Articulated

Maxillomandibular Relations Preparing The Occlusion Rim Receive To Bite Fork

Maxillomandibular Relations The Bite Fork To Occlusion Rim Using Alu Wax

Maxillomandibular Relations The Looking stem Of The Bite Forjk To Tranverse Rod

Maxillomandibular Relations Positioning And Looking The Orbital Pointer

Question 4. Occlusal rims.
Answer:

Occlusal Rims Definition:

Occluding surfaces built on temporary or permanent denture bases for the purpose of making maxillo- mandibular relation records & arranging teeth

Occlusal Rims Factors Controlling It:

1. Relationship Of Natural Teeth To The Bone:

  • Rims should be parallel to the long axis of teeth to be replaced
  • The maxillary anterior is labially inclined, and posteriors are vertically placed

2. Relationship Of Occlusal Rims To Edentulous Ridge:

  • Midline of the occlusal plane should pass through the apex of the edentulous ridge

3. Standard Dimensions:

  • Maxillary rims
  • Height: 22 mm
  • Width: 4-6 mm in the anterior region
  • Width: 8-12 mm in the posterior region

Maxillomandibular Relations Ideal Measurements Required For Maxillary Occlusal Rim

  • Mandibular rims
  • Height: 6-8 mm
  • Width: 4-6 mm in the anterior region
  • Width: 8-12 mm in the posterior region

Maxillomandibular Relations Ideal Measurements Required For A Mandibular Occlusal Rim

4. Clinical Guidelines:

  • Maxillary anterior edge 0-2 mm below the upper lip
  • Maxillary posterior occlusal plane 1/4th inch below the opening of Stenson’s duct
  • Mandibular incisal edge at the level of the lower lip
  • Canine eminence at the corner of the mouth

Maxillomandibular Relations Clinical Guide Lines For Cheking To Occlusal Rims

5. Techniques For Fabrications:

Maxillomandibular Relations tecniques For Fabrications And Rolled wax Tecnique

  • Rolled Wax technique
  • Metal occlusal rim former
  • Pre-formed Occlusal rim

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