1. Articulator
   1. A mechanical device which represents the TMJ & the jaw members to which maxillary & mandibular cast may be attached to simulate jaw movements
   2. Uses
      1. To hold casts in fixed manner
      2. To open & close in hinge like manner
      3. Mounting of casts for diagnosis, treatment planning & patient presentation
      4. Teeth arrangement for CD & RPD
      5. To produce diagnostic sliding motions of teeth similar to those in the mouth
      6. To produce diagnostic sliding motions of teeth similar to those in the mouth
   3. Classification
      1. Based on theories of occlusion
         1. Bonwill's equilateral triangle theory
            1. Bonwill articulators
         2. Hall's conical theory
            1. Hall articulator
         3. Monson's spherical theory
      2. Based on adjustability
         1. Non adjustable articulators
            1. eg. Mean value articulator
         2. Semi adjustable articulators
            1. Eg. Arcon articulator
            2. Term is given by : Bergstrom
            3. Condylar guide is located in upper member. Condylar analogue or sphere is located in lower member
            4. Eg. Whipmax, Ney (Class III)
            5. Eg. Non arcon articulator
            6. Condylar analogue or sphere is located in the upper member. Condylar guide is located in lower member
            7. Eg. Hanau articulators Gysi Dentatus
         3. Fully adjustable articulators
            1. Also called as Class IV articulator
            2. Eg. Stuart instrument gnathoscope
      3. International workshop on CD occlusion at University of Michigan 1972
         1. Class I
            1. Simple holding instruments capable of accepting single static registration
            2. Eg. Slab articulator, Hinge joint, Barndor
         2. Class II
            1. Instruments that permit horizontal + vertical motion but don't permit Facebow transfer
            2. II a
            3. Eg. Mean value articulator, Gysi simplex
            4. II b
            5. Eg. Monson's, Hall's articulator
            6. II c
            7. Eg. House articulator
         3. Class III
            1. Permits Horizontal + vertical motion & also accept Facebow transfer
            2. III a
            3. Eg. Hanau H, Dentatus
            4. III b
            5. Eg. Ney, Teledyne, Panadent
         4. Class IV
            1. Accept 3D dynamic registrations
            2. IV a
            3. Eg. TMJ Articulator
            4. IV b
            5. Eg. Stuart instrument gnathoscope, Pantograph, Denar
   4. Bennett Movement
      1. Defined as Direct lateral shift of mandible occurring simultaneously with lateral mandibular excursion
      2. Influences Faciolingual position of teeth
      3. Bennett Angle - Angle made by path of balancing side condyle with sagittal plane during lateral excursion
      4. Average Bennett shift - 1-1.5mm/ side
      5. Average Bennett angle is 15 degrees
      6. L = H/8 + 12 where , L is Bennett angle H is Horizontal condylar inclination
   5. Intercondylar distance
      1. Fixed for Hanau H2 (Non arcon), Hanau H1 (Arcon), Mean value articulator Value is 110mm
      2. Can be adjusted in Whipmax articulator. 3 positions :- ▪︎Small - 96mm ▪︎Medium - 110mm ▪︎Large - 124mm
   6. Thielemann's formula
      1. Balanced occlusion = CG X IG ____________________ CC X CI X OP
         1. CG = Condylar guidance IG = Incisal guidance CC = Compensatory curves CI = Cuspal inclination OP = Occlusal plane
2. TEETH SELECTION
   1. Anterior teeth selection
      1. Tooth size
         1. Size of teeth should be proportional to size of face
            1. Women's - smaller size than men's
            2. Following factors are used as a guide :
            3. 1. Pre-extraction records - photographs, radiographs, diagnostic casts
            4. 2. Anthropological measurements Total width of upper anterior = Circumference of head/13 Width of upper CI = Bizygomatic width/ 16 Width of upper CI = Length of face / 20 Length of upper CI = Length of face/ 16
            5. 3. Anatomic landmarks
            6. 4. Theoretical concepts
      2. Tooth shape
         1. Based on :
            1. 1) Patient's profile : ▪︎Straight or Curved
            2. 2) Facial form : Leon Williams classification- ▪︎Square ▪︎Tapering ▪︎Ovoid ▪︎Combination
            3. 3) Dentogenic concept/ SPA Concept
            4. Given by : FRUSH & FISCHER, 1957
            5. S - Sex : Curved features are associated with femininity Square features - masculinity
            6. P - Personality : 1) Vigorous :- Square with flat incisal edges 2) Delicate :- Ovoid teeth
            7. A - Age : Increasing age :- Incisal edges becomes flat & labial surface flatters & appears squarer
      3. Tooth colour
         1. Based on
            1. 1) Colour of hair, eyes, skin
            2. ▪︎Fair skin : lighter shade ▪︎Ruddy complexion, black/dark eyes : Dark shade
            3. 2) Age: With increasing age - teeth becomes darker
            4. 3) Sex : Females - lighter shade Males - darker shade
      4. Tooth material
         1. ▪︎Esthetics
            1. Higher
            2. Less
         2. ▪︎Attachment to denture base
            1. Mechanical - using pins & diatoric holes
            2. Chemical bonding - don't debond easily
         3. ▪︎Brittleness
            1. Higher
            2. Lower
         4. ▪︎Hardness
            1. Higher - abrades opposing teeth VD is maintained
            2. Less - don't abrade opposing teeth Loss of VD
         5. ▪︎Clicking sound
            1. Has clicking sound
            2. No clicking sound
         6. ▪︎Density
            1. Higher
            2. Lower
   2. Posterior teeth selection
      1. Based on
         1. 1) Size
            1. ▪︎Buccolingual width ▪︎Mesiodistal width ▪︎Vertical height
         2. 2) Form of teeth
            1. ▪︎Anatomic - 33° angulation ▪︎Semi-anatomic- < 30° ▪︎Non-anatomic/Cuspless - 0°
3. TEETH SETTING
   1. Maxillary Anterior teeth
      1. Alevolar ridge : Teeth are placed Anterior/labial/facial to the ridge
      2. Incisive papilla : ▪︎Guide for Upper incisors ▪︎Labial surface of incisors - 8-10mm anterior to incisive papilla
      3. For better aesthetics : teeth are set parallel to inner canthus - angle of mouth line
      4. ▪︎Lip support is provided by : Labial surface of teeth ▪︎Visibility of incisal edges should be : 1-2mm below upper lip at rest
      5. Overjet & overbite of teeth are determined by : esthetics & phonetics
      6. TRUBYTE TOOTH INDICATOR
         1. Uses : ▪︎To determine Form & dimensions of upper central incisor using a template ▪︎Based on theory of Leon Williams
   2. Posterior teeth
      1. Mandibular teeth - set up such that central fossa of posteriors lie on an imaginary line connecting the tip of canine to centre of retromolar pad
      2. Maxillary teeth - set up such that palatal cusps of posterior teeth should lie on the imaginary line
      3. Setting teeth too buccally causes - ▪︎Excessive lever forces of both dentures causing repeated midline fractures ▪︎Tendency of cheek biting
      4. Setting Too lingually to the ridge causes - ▪︎ Tongue biting ▪︎ Gagging ▪︎ Reduced chewing efficiency
      5. Buccolingual width of posterior teeth - should be less than natural teeth they replace
   3. Non anatomic/Cusp-less/Monoplane teeth
      1. Indications
         1. ▪︎Flat ridges ▪︎Knife edged ridges ▪︎Poor mucosa health ▪︎Lack of neuromuscular control ▪︎Patients with bruxism ▪︎Patients with Parkinsons disease ▪︎Patient with old denture which is severely attritted with reduced cusp height