VIII) STANDARD CLASSIFICATION ^ c > r s w \\ h -fhe standard approach for articulator classification is base3 on the Q|ossaixof jiynsfhodontic Terms. which classifies articulators into four types: Class I through Class IV. This system appears to be biased on mechanical adjustability. Class I This is a simple holding instrument capable of accepting a single static registration. Vertical motion is possible. Class II: Monson Maxillomandibular instrument based on geometry &his is an instrument that permits horizontal as well as vertical motion but does not Jate the motion to the temporomandibular joints. |is is an instrument %at simulates condylar pathways by using averages or lanical equivalents for all or part of the motion. These instruments allow for lentation of the
Transcript
VIII) STANDARD CLASSIFICATION
^ c > r s w \\ h
-fhe standard approach for articulator classification is base3 on the Q|ossaixof jiynsfhodontic Terms. which classifies articulators into four types: Class I through Class IV. This system appears to be biased on mechanical adjustability. Class I
This is a simple holding instrument capable of accepting a single static registration. Vertical motion is possible.
Class II: Monson Maxillomandibular instrument based on geometry
&his is an instrument that permits horizontal as well as vertical motion but does not Jate the motion to the temporomandibular joints.
|is is an instrument %at simulates condylar pathways by using averages or
lanical equivalents for all or part of the motion. These instruments allow for lentation of the
: relative to the joints and may be arcon or non-arcon instruments, rcon articulator - An articulator that maintains anatomic guidelines by the use of iylar analogs in the mandibular element and fossa assemblies in the maxillary lent.
Class III: Hanau non adjustable condyle
movement instrument
Class IV.
This is an instrument that will accept three-. These instruments allow for orientation of the cast to. the temporomandibular joints 'and replication of all mandibular movements.
Fully adjustable condylar simulating instrument which will accept dynamic registrations.
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IX) OPEN-END DENTAL RELATER CLASSIFICATION
Mis an alternative classification system. It is comprehensive but complex. For ^discussion here is an alternative classification of articulators. Advantages of ^system allows for organization of instruments based on a historical and ristic relationship. It is open-ended and further allows for development of lods beyond today's current technology. This includes cast Relators as Isolators.
his a holding device for relating casts with a fixed intermaxillary relationship fthe possibility of a hinge opening only function. Frequently there was a hinge rto enable the operator to see and use the intermaxillary space if no teeth were |table to stop further closure of the intermaxillary space. There was no Rotation of the motion to the TM joints and there was no relation to excursive Ction of the mandible
•based on Monson spheric theory of occlusion in which each cusp and incisal edge conforms to a segment_ of the surface of a sphere.£ inches in diameter with its center at the Glabella
(Glabella is the median elevation which connects the two superciliary arches) •Upper member of instruments moves antero-posteriorly and medio-laterally, According to this theory.
The Monson Maxillomandibular articulator
lass II-C:
Permits eccentric motion based on engraved records obtained from the patient and will not accept a face bow transfer. S.g.: House articulator (by M.M House in 1927) :asts are mounted arbitrarily.
instrument is adjusted by means of a Needles - houseJ'Chew in", which Imploys 4 metal studs in the upper occlusion rim against the lower compound delusion rim. Diamond - shaped-pathways -are generated. Instrument also |Tmploys a rotary grinder on the upper member for milling in a 40/1000 inches (glliptic area so as to free the occlusion in the centric occlusion.
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The House articulator
Class III:
Simulate or part of motion.
This instrument allows for joint orientation of the cast via a face bow transfer.
new average value articulator is the Hanau-Mate. ¦It is an Arcon instrument and will accept a face-bow transfer. It has an average horizontal condylar guidance of 30° and Bennett angle of 15°. Incisal guide table has an average value of 10° for both protrusive and lateral movement. The Upper member is removable for waxing ease by releasing the two condylar Jocks. It will not accept static protrusive or lateral interocclusal records. Therefore, it cannot be classified as III-A or III-B.
ember.
Bennett angle (L) is calculated from the horizontal condylar inclination (H) by means of Hanau's equation, L = H/8 +12.
If horizontal condylar inclination is 30°, then the Bennett angle would be 16° | approximately.
§ Hanau Model H articulator is the forerunner of Hanau H2. gDentatus (in 1944)
Relationship between upper and lower members can be standardized with a luge block", so that the casts can transferred from one articulator to another id still maintain the same relationship.
EVrcon (in 1950 by Bergstrom). [Similar to Hanau H, except that the condyles are on the lower member, and ^condylar guides are curved and on the upper member, rcon = Articulator + Condyle.
gftruments that have condyles on the upper member and condylar guides on flower member, e.g. Hanau Model H, are called as Condylar instruments or |Nbn Arcon instruments.
5te: "Bergstrom" was the first to use the term Arcon.
For complete denture construction, the fact that an instrument is either an Arcon orNon-Arcon seems to make little difference.
One advantage of an Arcon articulator is that the condyle moves m^a relationship to their condylar housings that are similar to the way the co;iuy.es move in relationship to the glenoid fps&ae in the skull. This does seem to make visualization and understanding of condylar movements easier.
The Hanau Model H articulator
The Dentatus articulator
Class III-B:
Accepts a Face-Bow transfer. i- Accepts Protrusive inter-occlusal records, and some 1 at ejal. io.ter^occ 1 usa 1 repords.
[e.g. 1. Gysi Trubyte articulator:
-;Non -Arcon instxuraent with a fixed inter condylar distance, ^-horizontal condylar inclination are individually adjustable, and individual ;Bennet adjustments are located near the center of the inter-condylar axis. The fincisal guide table is adjusted to the patient's Gothic arch angle. This instrument liable to accept some, but not all, lateral inter-occlusal records.
f. Hanau Kinoscope (by Hanau in 1927) Ik-has double condylar posts on each side.
g-inner condylar posts have the horizontal condylar guides and are adjusted ledio-laterally to produce mechanical equivalents of inter-condylar distance. ]Bennett angle is adjusted by rotating eccentric cones against the horizontal (is shaft.
yStansberry tripod type articulator (In 1928)
H One mechanical guide located posteriorly and two guides anteriorly. iThese guides are set by means of positional interocclusal records.
pNey articulator (By De Pietro in 1960) j,True Arcon instrument SFirst articulator to have condylar housings that contained adjustable rear, ledial and top walls in one assembly. ^Intercondylar distance adjustable
Recommended technique for these instrument employes positional records.
5. Hanau 130 -21 (By Richard Beu and James Janik in 1964)
- Most sophisticated articulator of the Hanau university series of articulators.
-It is utilized with protrusive and lateral interocclusal records.
6. Teledyne articulator (By Richard Beu of the Hanau division of Teledyne dental in 1975)
. Arcon instrument with adjustable medial and rear walls and adjustable horizontal condylar guidances. -Intercondylar distance is fixed.
- With lateral interocclusal records, the patient's Intercondylar distance is simulated by adjusting the rear walls.
"7. Panadent articulator (By Robert Lee)
Utilizes interchangeable preformed curved analog fossae for condylar • pathways. Arcon instrument
- Fixed Intercondylar distance
The Gysi Trubyte articulator
The Hanau Kinoscope articulator
The Hanau University Series 130-21
(A)Thc Telcdyne articulator
(B) The adjustable medial and rear walls of the Teledyne articulator.
The Hanau University Series 130-21
The Hanau University Series 130-28 articulator
(A)Thc Telcdyne articulator
(B) The adjustable medial and rear walls of the Teledyne articulator.
(A)The Panadent PCL articulator (I^l'anadent performed curved analog fossae.
(C)Panadent Axi-l'ath recorder on patient.
J CLASS IV-A:
-Accept three dimensional dynamic registrations and utilize a Face-bow ^transfer.
-Condylar pathways, or cams, are formed by registrations engraved by the patient.
- Do not allow for discriminatory capability of the condylar pathways i.e. condylar pathways must be used as generated by the patient and cannot be selectively modified prior to developing the patient's occlusion.
1. TMJ articulator (By Kenneth Swanson in 1965) - An intraoral registration is generated by studs in auto polymerizing resin | similar to the technique utilized with the House articulator, called articulator jk "Stereographic recording".
This recording is placed on the articulator and used to mould fossae in auto-polymerizing resin.
kThis fossae produce an accurate analog of patient's TMJ function.
CLASS IV-B:
1. Pantographic tracing apparatus
- Accept 3 dimensional dynamic registrations and utilize a Face-bow transfer.
- Condylar pathways can be selectively angled and customized.
- It uses pantographic tracing procedures for three dimensional dynamic registrations.
- Six Styli and-tracing tables are attached to the maxilla and mandible by means of Face-bows and clutches attached to the mandible and maxilla.
- Two tracing tables are located adjacent to each condylar area in the horizontal and vertical planes.
- Mandibular movements then produce pantograms .on the tracingi&bles.
- All the movements are repeatable except for the protrusive pathway.
• These tracings are transferred to the articulator in the same relationship in which they exist in the patient.
Reason behind selective adjustment is that it allows certain occlusal tolerances to be programmed in the articulator prior to the development of
• the patient occlusion, otherwise without selective adjustment; additional
" carving or grinding will be required during the development of patient
« occlusion.
• Willy S.W.Chang in a study tests the reliability and validity of the
• electronic pantograph in calculating condylar settings for 5 different articulators (Denar D5A, Denar Mark II, Whip Mix 8500, Hanau Modular, and Panadent PCH). Pantograph sensors were mounted to each articulator
I with custom-made mounting devices. Border movements were made on each articulator with known condylar settings to produce readings at 3-, 5-, and
• 10-mm condylotrack distances. The condylar settings investigated included horizontal condylar inclination, immediate mandibular lateral translation,
progressive mandibular lateral translation, top wall, and rear wall. The study concluded that the standard deviations for assessing reliability and the mean deviations for assessing validity were both relatively small in comparison to the average values of the condylar determinants. Therefore, the electronic pantograph was determined to be both reliable and valid."
3.*Pantronic (by Denar in 1982):
-Electronic pantograph which provides a computer print-out of numerical (jpndylar. measurements.
I"
'Advantages of Pantronic in comparison with pantographic tracing :
[Less time consuming. Several electronic tracings can be made consecutively. Condylar measurements compared immediately via the computer print-out.
Hi class IV-B, all instruments are
-Arcon with adjustable Intercondylar distances.
Condylar housings can be adjusted in the horizontal, Sagittal,. & frontal ' planes.
Each has a Bennett guide adjustment. > All accept arbitrary or hinge axis Face-bow transfers.
Referred as Gnathologic instruments, because of their full adjustability. ^Note: According to GPT, Gnathology is a science that deals with the linasticatory apparatus as a whole, including morphology, anatomy, histology, [physiology, pathology and thereuptics.
EVhile Gnathology, according to dentists is the study of occlusion and occlusal [rehabilitation through the used of Pantographs and fully adjustable articulators.
P
[Gnathoscope (By Charles Stuart in 1955):
-Bennett guides are situated in the middle of the posterior aspect of the Strument similar to Gysi Trubyte articulator.
-Benett guide can be angulated and customized
Numerous plastic condylar inserts are available
ing the past 15 years there has been a renewed interest in occlusal patterns everyday dentistry. This was brought primarily by Niles Guichet of Anaheim, |lifornia).
1968, Niles Guichet designed Denar D4A i.e. fully adjustable articulator.
D5A is the current Denar fully adjustable articulator and is similar to D4A except for refinements in machining and in the centnc iatch mechanism located at the rear of the articulator. Plastic condylar inserts arc available. Benett adjustment is located in the medial wall of the condylar housing and has provisions for both immediate side shift (straight) and progressive side shift (angular) adjustments.
4. Simulator by Ernest Granger:
Bennett guides can be set by adjustment only and cannot be customized (point of difference with Class IV-B)
(A) Pantographic tracing apparatus assembled on patient.
(B) Posterior vertical and horizontal tracing tables with pantograms.
(C) Anterior horizontal pantograms.
(D) Representative pantograms from a patient.
(E) Pantographic tracing apparatus removed from patient.
(F) Transfer of pantographic tracing to the articulator.
..........
(A)Pantronic instrumentation.
(B)Pantronic instrument assembled on patient. (QPantronic computer printout of condylar measurements.
The Stuart articulator
II. BERG STROM'S CLASSIFICATION OF ARTICULATORS42 1. Arcon 2. Non Arcon
f L t v- - ¦
1. Arcon : Instruments that have condyles^ on the lower member and the condylar guides on the upper members are called Arcon articulators llg. Ney articulators, Panadent, Teledyne, whip mix, Hanau H2, Hanau radial shift, Hanau wide vue.
2. Non Arcon : Instruments that have condyles on the upper member and condylar guides on the lower members are called Non Arcon. e.g. Hanau model H
DIFFERENCES IN PERFORMANCE BETWEEN ARCON AND NONARCON ARTICULATORS
pfo set the condylar inclinations on a semiadjustable instrument, wax wafers ailed interocclusal records, or check bites, are used to transfer the terminal sitions of the condyles from the skull to the instrument. These wafers are 3 to mm thick, so that the teeth on the maxillary and mandibular casts are separated by that distance when the condylar inclinations are set. When the wafers are emoved from an arcon articulator, and the teeth are closed together, the Condylar inclination will remain the same. However, when the teeth are closed n a nonarcon articulator, the inclination changes, becoming less steep. Arcon iculators have become more widely used because of their accuracy and the ase with which they disassemble to facilitate the occlusal waxing required for ast gold restorations. This very feature makes them unpopular for arranging enture teeth. The centric position is less easily maintained when the occlusion n.all of the posterior teeth is being manipulated. Therefore, the nonarcon trument has been more popular for the fabrication of dentures. Arcon 'culators equipped with firm centric latches that prevent posterior separation '11 overcome many of these objections.___
•¦Fig* The angle between the condylar inclination and the occlusal plane of the ihaxillary teeth remains constant between an open (A) And a closed (B) arcon . articulator <al = <a2 . However, the angle changes between an open (C) And a closed (D) nonarcon instrument <a3 <a4 . For the amount of opening illustrated, ;.thcre would be a difference of 8 degrees between the condylar inclination at an f^pen position (where the articulator settings are adjusted) and a closed position at Kwflich the articulator is used.
fyiiayiota Hatzi et-al investigated in a study whether mounted casts could be isferred from 1 articulator to another with positional accuracy and whether the [ lunge axis was reproducible in each of the articulators tested. They concluded that tl'simple or complex reconstruction is transferred from one articulator to
another is not exactly the same, then the occlusion will be compromised. To assure the "possible accuracy regarding the properties tested, the clinician should [erstand that no 2 articulators are exactly the same and that it may be judicious
JII. Classification of articulators: 44
Adjustable l.Rectilincar Guidances
Denar Mark II Denar Omni Denar Track II Dcntatus
Hanau 183 Wide Vue Hanau 184 Wide Vue Hanau 145 Wide Vue Hanau 158 Wide Vue Hanau 96 H2 Hanau 181-101 Quick Perfect TMJ Deluxe with Mechanical fossae. TMJ Mini with Mechanical Fossae. SAM
'-Twin stage occluder Class II(Type 2) A/ ' -Monson iHandy II .(The correlator Transgraph The Gnathic Relator Verticulator ass II (Type 3) louse Dentatus 'anau
hip Mix Penar-Mark II & Omni model
-Mechanical fossa &molded fossa
anadent
Ss II (Type 4) Stansberry Tripod ¦lie Dentograph iah Dupli-Functional
Class I
> Receive& Reproduce Stereograms(pantograms)
> Permit individual condylar movements in each of 3 planes.
> Capable of reproducing timing of the side shift of the orbiting (balancing) side & its direction on the rotating (working) side.
> Four dimensional instruments(because they include timing also)
> Capable of being set to reproduce tooth movement along border pathways in three planes.
Class II-
> Not receive Stereograms.
> Some have fixed controls, others are adjustable but not in more than two planes.
> Most set to anatomic averages or with some type of positional records.
> Mini-recording devices & premolded fossae are available, j > Close approximation of condylar movement patterns determined
quickly, i Type 1 (Hinge)-
> Opening & closing in a hinge movement.
> Few Permit limited non -adjustable excursive like movements.
Type 2(Arbitrary)-
> Designed to adapt to specific theories of occlusion. Type 3(Average)-
> Provide condylar guidance by means of averages, positional records.
> Permits movement of both horizontal & lateral guidance surfaces
> Face -Bow can be used. Type 4(Special)-
> Designed primarily for complete dentures.
*rticulators based on theories of occlusion 46
a) BONWILL'S THEORY OF OCCLUSION: It is also known as the of equilateral triangle, which has a 4-inch (lOcms) distance between the les and betweeFfeacti condyle and to the lower central incisor point. E.g.: U's articulator, Gysi simplex articulator. Since condylar guidances were not ble, only movement in horizontal plane is permitted.
b) CONICAL THEORY OF OCCLUSION: Lower teeth move over the surfaces of the upper teeth as over the surface of a cone, with a generating angle of 45 degrees and the central axis of the cone tipped at 45 degrees to the occlusal plane. E.g. Hall Automatic articulator-teeth with 45 degrees cusps were necessary for constructing dentures on this type of articulator.
c) SPHERICAL THEORY OF OCCLUSION:
It was proposed by G.S. Monson in 1918. The lower teeth move over the surface of the upper teeth as over the surface of a sphere with a diameter of Ji inches (20cms),- The center of the sphere is located in the region of the glabella and the surface of the sphere passes through the glenoid fossa along the articulating Imminences "or concentric with them. Van Spee, a German anatomist, based this theory on observations of natural teeth and skulls. E.g.: Monson's Maxillo-4Mandibular Instrument. The failure of these articulators based on theories is Kbecause of one common fault - provision was not made for variations from the stheoretical relationship that occurs in different persons.
yi) Many investigators have classified articulators in various methods:
Gills (1926), Boucher (1934), Kingery (1934) divided articulator into adjustable and nonadjustable.
Back (1962) classified into suspension instrument, axis instrument and the tripod movement.
