Articulatorpowerpoint/ dental implant courses by Indian dental academy

ARTICULATORS INDIAN ACADEMY

DENTAL

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ARTICULATORS Definition: Articulator may be defined as a mechanical device that represents human Temporomandibular joint and jaw members to which maxillary ands mandibular cast are attached to simulate jaw movements.

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FUNCTIONS ď Ź The primary function of the articulator is to act as a representative in patients ď Ź It is used to simulate the patients Temporomandibular joint, muscles of mastication, mandibular ligaments, maxilla and mandible and the complex neuromuscular mechanism that programmes the mandibular movements. www.indiandentalacademy.com

ď Ź The articulator is made to simulate the equivalent movements of the TMJ but does not duplicate or produce identical movements as in the human mouth ď Ź It forms an important instrument to the dentist as it can be programmed with certain patients records allowing the operator and laboratory technician to fabricate a restoration that will be physiologically and psychologically acceptable. www.indiandentalacademy.com

ADVANTAGES  Properly mounted cast allow the operated to better visualize the patient occlusion from the lingual side.  Patient’ s co-operation is not required once the Interocclusal records are obtained from the patients  Refinement of the complete dentures in the patient’ s mouth is extremely difficult because of shifting of denture bases and resiliency of the supporting tissues. This does not take place in the articulator. www.indiandentalacademy.com

 Chair side appointment is reduced and more work can be designated to the auxiliary personnel.  Patient’ s tongue saliva, check etc. are not a factors of hinderence under using the articulator

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LIMITATIONS ď Ź An articulator is a mechanical device made by metal hence is subjected to error in tooling and there by resulting from fatigue and bear ď Ź Articulator will not duplicate but simulates the condylar movements of TMJ

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REQUIREMENTS  It should hold casts in correct horizontal and vertical relationships i.e., centric relations.  It should provide a positive anterior vertical stop.  It should accept a face bow transfer record. It should open and close in a hinge movement.  It should allow protrusive and lateral jaw motions  Moving parts should move freely and accurately  Moving parts should be often rigid construction  Should be easy to fix and attach the maxillary and mandibular cast to the articulator and also to attach from the articulators www.indiandentalacademy.com

Additional Requirements  Adjustable horizontal, lateral condylar guide element & allow protrusive movements  A mechanism to accept the 3rd point of reference from a face bow  A terminal hinge locking positional device  Removable mounting plates that can be positioned accurately  An adjustable incisal guide table  Adjustable intercondylar width of the condylar element www.indiandentalacademy.com

Classification of Articulators

ď ŹAn articulator classification was developed based on the instruments function, instrument capability, intent, registration procedure and registration acceptance were considered. www.indiandentalacademy.com

Classification based on Theories of Occlusion  BONWILLS THEORY OF OCCLUSION  CONICAL THEORY OF OCCLUSION  ( R.E.Hall )  SPHERICAL THEORY OF OCCLUSION (G.S.Monson 1918 )

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 BONWILLS THEORY OF OCCLUSION Also know as THEORY OF EQUILATERAL TRIANGLE.

It stated that a 4" (10 cm ) distance occurs between the condyles and between each condyle & the incisal point E.g. Bonwills articulator www.indiandentalacademy.com

CONICAL THEORY OF OCCLUSION R.E.HALL proposed that the lower teeth move over the surface of the upper teeth as over the surface of a cone with an angle of 45째 with the central axis of the cone tipped at 45째 Angle to the occlusal plane E.g. Hall automatic articulator. teeth with 45째 cusp are necessary to construct dentures on these articulators.

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 SPHERICAL THEORY OF OCCLUSION (Monson 1918)  Monson proposed that lower teeth moves over the surface of the upper teeth as over the surface of a sphere with a diameter of 8 " (20cm). the center of the sphere is located in the region of Glabella & the surfaces of the sphere passes through the Glenoid fossa along the articulating eminences.  E.g. Maxillomandibular instrument.

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ď Ź Drawbacks Articulators based on theories of occlusion was that they made no provision for variation from the theoretical relationships that occurs in different people.

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CLASSIFICATION BASED ON THE TYPES OF RECORDS USED FOR THEIR ADJUSTMENT  INTEROCCLUSAL RECORD ADJUSTMENT  GRAPHIC RECORD ADJUSTMENT  HINGE AXIS LOCATION FOR ADJUSTING ARTICULATORS

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INTEROCCLUSAL RECORD ADJUSTMENT ď Ź These records may be made in wax, dental plaster ZnOE paste or cold-cure acrylic resin.

Each of these records are of only one positional relationship of the lower jaw to the upper jaw ď Ź Either centric or to protrusive OR Centric or to lateral record E.g. Hanau articulators www.indiandentalacademy.com

GRAPHIC RECORD ADJUSTMENT ď Ź The graphic records consists of records of the extreme border positions of mandibular movement which are curved and the articulators must be capable of producing at least the equivalent of curved movements ď Ź simple procedure if natural teeth exists in both jaws & it becomes difficult and unreliable in edentulous patients www.indiandentalacademy.com

HINGE AXIS LOCATION FOR ADJUSTING ARTICULATOR

ď ŹCorrect location of the opening axis of mandibular hinge axis is essential for the correct adjustment of instrument

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CLASSIFICATION OF ARTICULATORS USING NEW SYSTEMS  FULLY ADJUSTABLE ARTICULATORS  SEMI ADJUSTABLE ARTICULATORS  NON ADJUSTABLE ARTICULATORS

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ď Ź FULLY ADJUSTABLE ARTICULATORS ď Ź Articulators which can accept all the following 5 records 1).Face bow transfer 2) Centric jaw relation record 3) Protrusive record 4) Lateral records 5) Intercondylar distance record E.g.. Hanau kinescope(1923) Mc Collum Gnathoscope(1935) Granger Gnatholator (1950) Stuarticulator(1955) Ney-Depietro(1962) Hanau 130-21 (1953) Simulator (1968) Dentar D4-A (1968) www.indiandentalacademy.com

SEMIADJUSTABLE ARTICULATORS Articulators which can accept the following 3 record 1).Face bow transfer 2) Centric jaw relation record 3) Protrusive record

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E.g.  Snow Acme (1910)  Gysi Adaptable (1910) (does not accept lateral record )  Wadsworth (1924)  Hanau H (1922)  Gysi Trubyte (1926) (does not accept intercondylar records )  House(1927) (does not accept intercondylar records & satisfies Bonwills principle)  Dentatus (1944)  Bergstorm Arcon(1950)  Hanau 130-28 (1963)  Whip-mix (1968) www.indiandentalacademy.com

NONADJUSTABLE ARTICULATORS Articulators which can accept 1 OR 2 of the following 3 records 1).Face bow transfer 2) Centric jaw relation record 3) Protrusive record Gariot (1805) Evans (1840) Barn door hinge (1858) Bonwill (1858) Walker (1896) Has adjustable condylar guidance but does not accept face bow record www.indiandentalacademy.com

 Gritman (1899)  Snow (1906)  Gysisimplex (1912 ) Monson (1918)  Stansbery (1929)  Based on Tripod theory (no condylar control )  Phillips Occlusoscope (1931) (tripod theory & does not accept face bow record )  Kile Dentograph (1945 ) ( tripod principle )  Transograph (1952 ) ( contains 2 face bows & no condylar guidance )  Pankey-Mann (1955) (Based on spherical theory ) www.indiandentalacademy.com

BASED ON INSTRUMENT FUNCTION International Prosthodontics workshop ď Ź Class I – Simple holding instruments capable of accepting a single static registration. Vertical motion is possible, but only for convenience E.g..

Slab articulator, barn door hinge articulator

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 Class II – Instrument that permit horizontal as well as vertical motion but do not orient the motion to the TMJ via, a face bow transfer.  Class II AThese articulators permit eccentric motion based on average or arbitrary values.

E.g.. – GYSI Simplex articulators. www.indiandentalacademy.com

ď Ź Class II B- Articulators permit only eccentric movements based on theories of arbitrary motion. ď Ź E.g..-Monson Maxillomandibular articulators

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ď Ź Class IIC Articulators permit eccentric motion determined by the patient using engraving methods ď Ź E.g..-House articulator

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 Class III – Instrument can accept a face bow transfer.  Class III A- Instrument that accept a static protrusive registration and use equivalents for the rest of the motion  E.g.: Hanau Model-H Articulator www.indiandentalacademy.com

ď Ź Class III B- Instrument in this class accept a face bow transfer, protrusive Interocclusal records, and some lateral Interocclusal records ď Ź E.g.: Trubyte articulator

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 Class IV – Instruments that will accepts three dimensional dynamic registration  Class IV A- Instruments in this class will accept three dimensional dynamic registrations and utilize a face bow transfer  E.g.: TMJ articulators

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 Class IV B – Instrument in this class will accept three dimensional dynamic registrations and utilize a face bow transfer  E.g.:- Denar

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Posselt Classification  Plane line or simple hinge type  Mean value type with fixed condylar part  Adjustable type In the first two types no control mechanism exists. Only the Interocclusal centric relation can be recorded. They lack individualized information concerning spatial relationship and occlusal arrangement of artificial teeth. So may not resemble patient actual jaw movements www.indiandentalacademy.com

Arcon and Non-Arcon articulators ď Ź Arcon Type: Instruments with condyles in the lower member and condylar guides on the upper. i.e., lower member is movable. ď Ź Non-Arcon type: Condyles are on the upper member and condylar guides on the lower member

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MEAN VALUE ARTICULATOR OR FIXED ARTICULATOR OR THREE POINT ARTICULATOR  It consists an upper and lower member representing the maxilla and mandible  Opens and closes around a axis i.e., the condylar shaft  Shaft is engaged in the condylar slot representing glenoid fossa  Vertical Separation is done by vertical pin  Vertical pin consists of a mid incisal pin  Condylar slot is inclined at the angulation of 33 0 to the horizontal plane www.indiandentalacademy.com

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 Distance between the two condyle slots is fixed and is 110 mm  Vertical pin rests on incisal table  Incisal table has an angulation of 50 into the horizontal plane  The distance between the centre of the centre of the condyle shaft and mid incisive pin is again.110 mm.  Based on Bonwill equilateral triangle

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HISTORY OF ARTICULATORS UPTO 1940

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PLASTER ARTICULATORS  It was 1st described by Phillips Pfaff (1756)  A plaster extension on the distal portion of the mandibular cast was grooved to serve as a guide for a plaster extension of the maxillary cast.  The extended casts together constituted the 1st articulator, commonly called a SLAB ARTICULATOR www.indiandentalacademy.com

BARN DOOR HINGE  Its hinge is modified by bending each arm 90°  FORM L-shaped upper & lower members.

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ADAPTABLE BARN DOOR HINGE

ď Ź It is capable of opening & closing only in a hinge movement. It has an anterior vertical stop, which is usually a machine bolt.

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 GARIOT HINGE JOINT ARTICULATOR  (J.B.GARIOT (1805)  It consists of 2 metal frames to which the casts are attached with a simple hinge & a set screw to hold the frames in fixed vertical position. www.indiandentalacademy.com

 BOWILLS ARTICULATOR(1858 )  It’s the 1st articulator developed to imitate the movements of the mandible in eccentric position.  Based on Bonwills theory of equilateral triangle www.indiandentalacademy.com

 KERR ARTICULATOR (1902)  It has fixed protrusive & lateral movements  Hinge is located on approximately the same plane as the occlusal plane of the mounted cast. www.indiandentalacademy.com

 NEW CENTURY ARTICULATOR (1906)  George B.Snow  It has a tension spring which allows a greater range of movement  Rotation centers placed 4" apart in accordance with Bonwills theory  Modified articulator has an incisal pin & post extension added to lower member to prevent tipping

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 ACME ARTICULATOR (1910)  George B.Snow  Its an elaboration of New Century Instrument (1910)  3 models of different widths that accommodate 3 ranges of intercondylar distance  Condylar paths are straight & adjustable condylar inclinations  Provided Bennett movement  Posterior adjustment is possible to increse the distance between upper & lower members  Guiding mechanisms are on the upper member www.indiandentalacademy.com

GYSI ADAPTABLE & GYSI SIMPLEX ARTICULATOR (1910) Alfred Gysi It was beyond the technical ability & finances of most dentists Extra oral tracing & parallel Condylar path plates accepted Gysi simplex (1914)was introduced as a mean value articulator It does not require great technical ability to operate & competitively priced  Condylar guidance is fixed at 33° & is shaped like the ogee path (S shaped curve in profile) www.indiandentalacademy.com  Incisal guide is not adjustable      

 MAXILLOMANDIBULAR INSTRUMENT (1918)  George Monson  Based on spherical theory  It has set screws to vary the instruments radius

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 HAGMAN BALANCER (1920)  Based on Spherical theory of occlusion  It opens & closes on a hinge that is in the center of the upright support  It doesnot require facebow & interocclusal records for mounting  This technique directs reconstruction of the mandibular teeth to the curve of Spee using a balanced occlusal guide  The maxillary teeth are constructed secondarily to conform to www.indiandentalacademy.com the mandibular teeth

 STEPHANS ARTICULATOR (1921)  Simiar to gariots hinge articulator  It has fixed condylar inlination & allows for an arbitrary lateral movement  A posterior set screw holds the upper & lower members of the articulator at a fixed vertical dimension www.indiandentalacademy.com

 HANAU MODEL M KINOSCOPE (1923)  Rudolph L.Hanau an engineer was influenced by Dr.Rupert E.Hall to study the design of articulators  It has double condylar posts on each side  Inner posts serve 2 purposes: they act as horizontal condylar guides & they have variable rotation centers when the posts are moved inward or outward.  Outer post- it helps to adjust the Bennett angle

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 HOMER RELATOR (1923)  Joseph Homer  Plastic material rather than mechanical guides is used to preserve articulator position  3 cups in lower member filled with plastic material (impression compound) capture the record & record the tripoded upper member into the recorded positions  Same principle is used in Irish Duplifunctional & TMJ instruments

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 WADSWORTH ARTICULATOR (1924)  Frank Wadsworth  Based on Monson's spherical theory  Casts are mounted with a face bow & Wadsworth T-attachment which determines the 3rd point of reference  It does not accept bilateral condylar symmetry  It has adjustable intercondylar distances www.indiandentalacademy.com

 HANAU MODEL H110 (1922)  It has individual condylar guidance adjustments in both sagittal & horizontal planes  It has incisal guide cup with its fixed curvature could be moved only as a unit & it did not have calibrations for resetting  Lateral setting is calculated by dividing the horizontal condylar inclination by 8 and adding 12  L = H\8 + 12

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 HANAU MODEL H110 MODIFIED (1927)  It has incisal guide table with calibrations instead of the incisal guide cup

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 PHILIPS STUDENT (PANTOGRAPHIC ) ARTICULATOR (1929)  George P.Philips  It’s a fully adaptable articulator because it follows any graphic record  It was designed to trace Gothic arch (needlepoint ) tracing & inclination of the glenoid fossa in one step

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STANBERY TRIPOD INSTRUMENT (1929) C.J.STANSBERY It was designed without a hinge to facilitate the reproduction of any positional relationship In this instrument there is no mechanical equivalent or representation of condyles The articulator reproduces positions not movements www.indiandentalacademy.com

 HOUSE ARTICULATOR (1930)  M.M.HOUSE in early 1930s  It was adjusted with maxillomandibular relation record that use the needle house method  It has a milling device for occlusal adjustment after denture processing  Intercondylar guidance, lateral condylar guidance are controlled by Bennett guide

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 PRECISION CO-ORDINATOR  W.H.Terrell (1930)  Its an arcon type of articulator that has curvilinear condylar guides  Twin parabolic cams control vertical & horizontal anterior guidance  Incisal pin is curved to allow for changes in the vertical dimension  A milling device, in the articulator can be varied from 0 to 0.04".

It mills circularly in the molar region, elliptically in the premolar region and laterally in the incisal region

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 HANAU CROWN & BRIDGE ARTICULATOR (1934)  It’s a small articulator & it doesnot require face bow transfer  It has a posterior pin & cam guidance mechanism ti stimulate working & balancing side excursions of 15°  It has a fixed protrusive movement of 30° www.indiandentalacademy.com

 PHILLIPS OCCLUSOSCOPE (1938)  George Phillips  No face bow transfer required  Its adjusted by either intra or extra oral tracing  Lower member has 2 adjustable units representing the TMJs which control the working inclination & balancing inclinations  There is no adjustable incisal guide www.indiandentalacademy.com

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