Total Pageviews

Thursday, March 8, 2012

Articulator

Articulators


   DEFINATION:  A Mechanical device that represents the temperomandibular joints and jaw members to which maxillary and mandibular casts may be attached to stimulate some or all of the mandibular movements.




PURPOSES
1.   To hold the maxillary and mandibular casts in a determined fixed relationship.
2. Mounting of dental casts for diagnosis treatment planning and patient presentation. 
3.To simulate the jaw movement like opening and closing.
4. Fabrication of occlusal surfaces for dental restoration.
5.  Arrangement of artificial teeth for complete and removable partial denture.

     USE
     1. To diagnose the state of occlusion in both the natural and artificial dentition
     2.  To plan the dental procedures based on the relationship between opposing natural and   
          artificial teeth.
       Ex.  Evaluation of the possibility of balance occlusion.
  • o    4.To aid in the fabrication of  restorations and prosthodontics replacements.
  • o    5.To correct and modified    complete restorations.
  • o    6.To arrange artificial teeth.


REQUIREMENTS
 Two Types of Requirements
a.   Minimal requirements
b.  Additional requirements
Minimal requirements
   They are necessory for the fabrication of complete denture to the patients centric position.
    They are –
1.  It must be accurately maintain the correct horizontal and vertical relationship of the patient’s casts.
2. The casts should be easily removable and attachable to the articulator without loosing their correct horizontal and vertical relationship
3. The articulator should have an incisal guide pin with a positive stop, that is adjustable and caliberated.

4. The articulator should be able to open and closed in a hinge like fashion.
5.  The articulator should accept a face-bow transfer utilizing an anterior reference point.
6.  The construction should be accurate, rigid and of non corrosive material.
7. The moving parts should move freely without any friction.
8.  The non moving parts should be of a rigid construction.
9. The design should be such that there is adequate distance between the upper and lower members.
10. The articulator should be stable on the laboratory bench and not too bulky and heavy.


CLASSIFICATION  OF  ARTICULATORS
Several basis of classification of articulator were proposed, some of them are as follows. 
      1. Based on the instruments function
      2. Based on theories of occlusion
      3. Based on the type of inter occlusal record used
      4. Based on the adjustabililty of the articulator.
 1. Based on the instruments function
                                 At the international prosthodontic workshop on complete denture occlusion at the university of Michigan in 1972, the articulators classified based on instrument capability, intent, recording procedure and record acceptance
 
  Class I    :  Hinge Type
  Class II   :  Arbitrary – type A
                                           type B
                                           type C
   Class III :  Average  -type A
                                        type  B
                
  Class IV :  Special –  type  A
                                       type  B  
  
   Class I    :  Hinge Type  
    
    
                  
1.These are simple articulator (Simple holding instruments) capable of accepting a single static registration.
2. Only Vertical motion possible.
3.Important features are positive stops and locks at the mounted position
4.Use in cases where a tentative jaw relation is done.
5.Class I instruments are suitable for crown and bridge, and operative instruments.
Subdivision A: vertical motion is possible. Ex: Corelator, Venticulator.
Subdivision B: vertical motion is joint related. Ex: Centric Relator
   
Examples of Class I :-     Slab articulator
                                           Hinge joint articulator – J.B. GARIOT (1805) 
                                           Barn door articulator 
                                            Gysi Simplex (Alfred Gysi, Zurich, 1914)

 CLASS II (Arbitary)
   
These articulator permits horizontal and vertical movements but they do not orient the movement to TMJ with a face-bow.        
They are –              
   1.  TYPE A :-
            Eccentric motion is unrelated to patient motion.         
                 Permit limited eccentric motion based on averages.
                 Do not permit face-bow transfer.
            The condyles are on the lower member of articulator.
              ( Based on Bonwill’s triangle)
             Ex. Mean-Value articulator - GYSI

    2.  TYPE B :-
            Permit limited eccentric motion based on arbitrary theory of motion .
                 Do not accept a face-bow transfer. ( Based on spheric theory of occlusion)

          
.
            Ex. A. Monson’s articulator  / Spherical Theory Articulator – Fournet &
                        Hageman  articulators
                   B. Hall’s articulator / Conical Theory Articulator   (  Shofu Handy II )
                               

  3. TYPE C :-
            Permit limited eccentric motion based on engraved records obtained from the patient.
                 Do not accept a face-bow transfer.
                  Ex.:-     House’s articulator (1920)
                            Gnathic Relator

CLASS III (Average)
1. They permit horizontal and vertical motion
2. Do accept face-bow transfer but these facility is limited.
3. Do Not / Cannot allow total customization of condylar pathways.
4. They simulate condylar pathways by using average or mechanical equivalents for the whole or part of the condylar motion.
5. They allow for joint orientation of the casts and may be arcon or nonarcon instruments. All the examples are arcon instruments, accept facebows, and have mounting plates for unlimited case load.
6.These instruments can fulfill the requirements for complete denture construction.
 7.Desirable features would be good centric lock, progressive and immediate side shift                   controls,protrusive inclination, intercenter distance adjustment, a simple mounting procedure, a good sturdy design, and an arcon arrangement
   They are –       Type A
                            Type B
1. TYPE A :-
                Accept static protrusive interocclusal records / registrations + Accepts a face-bow   
                 transfer
                Uses equivalents for other types of motions.
    Exp.    Hanau H articulator ( RUDOLPH HANAU , 1923) NON-ARCON
                Hanau H2 articulator – NON ARCON
                Bergstrom articulator (ARCON)  Dentatus (1944, Sweden)
                              
2.   TYPE B :-
                Accept a Static Lateral protrusive interocclusal records  + face-bow transfer
                Use equivalents for other types of motions
                 Exp.     Trubyte articulator        -   (GYSI, 1926) – NON ARCON
                             Tripod articulator         -   STANSBERRY
                             Ney articulator             -    (De Pietro , 1960) - ARCON
                             Hanau (130-21)            -    (Richard Beu & James Janik .1964)
                            Tele Dyne articulator   -   (Richard Beu ,1975) - ARCON
                            Pandent articulator       -   Robert Lee - ARCON
                                Denar Mark II
                                Whipmix
                                Case Articulator Simulator
                                TMJ Mechanical fossa Instrument

CLASS IV (Special)
 1.These articulator accept three dimensional dynamic registration.
  2.They are capable of accurately reproducing the condylar pathway for each patient.
 3.They allow point (joint) orientation of the casts using Face Bow Transfer
 4 .They allow for orientation of the cast to the temporomandibular joints and replication of all              mandibular movements.
5.These articulators are the instruments of choice for complete reconstructions.
6. These instruments should hold adjustments, contain good centric locking mechanism, versatile incisal guide tables, and stable mounting features, and be precision engineered.
    
They are –  Type  A
                   Type  B
  1) TYPE A :-
        Accept three dimensional dynamic registration + utilise a face-bow transfer.
        Condylar pathways are formed by registration engraved by the patient.
         This path is non - modifyable
           Exp.  TMJ articulator – Kenneth Swanson (1965) Stereograph
                               
2) TYPE B :-
       Accept three dimensional dynamic registration + utilise a face-bow transfer.
          Condylar pathway can be selectively angled and customized / modified.
            The procedure utilise the pantographic tracing.
                   EXP. Pantronic acticulator – Dener (1982)
                   Gnathoscope  - Charls Stuart
                   Denar D 4A & D 5A - Niles Guichet, 1968
                    Denar Model SE
                    Simulator  - Earnest Granger
 •   BASED ON THEORIES OF ARTICULATOR



1.Bonwill theory Articulators
    Designed by WGA Bonwill (Bonwill , 1858 : father of anatomic/balanced occlusion,
    equilateral triangle
      Known as theory of equilateral triangle.

   "Allow lateral movement & permit movement in horizontal plane."
Always model the upper wax (record base) first, judging the length of incisors and trial placement of anterior teeth for shade, shape, length and width. To articulate the lower cast, use a pair of dividers four inches apart with the center of the lower teeth at the median line just four inches from the condyles on either side
                
  Conical Theory Articulators
Designed b R.E. Hall (Hall, 1918 : adjustable 3D anatomic articulator; universal mandibular movements, adjustable incisal guide )
Lower teeth move over the surface of the upper teeth as over the surface of a cone generating an angle of 45 degree.

Spherical Theory Articulators



Designed by G. S. Monsoon (Monsoon, 1916 : Spherical theory of occlusion )
Lower teeth move over the surface of the upper teeth as over a surface of sphere with a diameter of 8inches.
                The center was located in the region of glabella.

 BASED TYPE OF INTEROCCLUSAL RECORDS USED:


Eccentric pathways can be dynamically registered either graphically (pantographic method) or stereographically (engraving method), positionally registered (checkbite method), determined by the articulator (mechanical equivalents), or adjusted entirely on the patient.
 
 BASED ON THE ADJUSTABILITY
Three Types :-
  a.  Non –   Adjustable
  b.  Semi –  Adjustable
  c.  Fully –  Adjustable

NON – ADJUSTABLE A.
Can open and close in a fixed horizontal axis.
Have a fixed condylar path.
The incisal pins ride on an inclined plate in a fixed inclination.
Can accept one or two of the following records: Face bow, centric jaw relation or protrusive record.
A class I articulator is a nonadjustable articulator.

SEMI ADJUSTABLE A.
Have adjustable horizontal condylar paths, adjustable lateral condylar path adjustable incisal guide table and adjustable inter condylar distance.
The degree and ease of these adjustments differ.
Can accept all three of the following records: Face bow, centric jaw relation or protrusive record.
A class II or III articulator is a semiadjustable articulator.
Two Type:-
    Arcon Type
    Non arcon Type
  1. ARCON Type
The term “Arcon” was derived by Bergstrom from the words Ar- Articulator & Con – Condyle
This articulator resembles the TMJ.
The Condylar Element / analogue / sphere àattached to – Lower Member (Movable)
The Condylar Guidance (~Glenoid Fossa) à attached to – Upper / Cranial Member (immovable)
Advantage: The Face Bow transfer, occlusal plane, and relationship of the opposing casts are preserved when the articulator is opened and closed.
Examples :-               Whipmix , 8500 ( DR. Charles Stuart, 1963)
                                Hanau H@, Arcon
                                Dentatus, ARA
                                  Ney articulator             -    (De Pietro , 1960)
                                 Tele Dyne articulator   -   (Richard Beu ,1975)
 
2. Non-Arcon type
This articulator is the reverse of the TMJ
The Condylar Element / analogue / sphere àattached to – Upper Member (Movable)
The Condylar Guidance (~Glenoid Fossa) à attached to – Lower Member (immovable)
Examples:-           Hanau , 96h20
                                Hanau, University
                                Gysi, adjustable
                                Trubyte articulator        -   (GYSI, 1926)
                                Dentatus, ARL
                                Hanau, Kinoscope
                                House, Rotary Grinder

FULLY ADJUSTABLE 
 
Capable of being adjusted to follow the mandibular movement in all direction.
They have numerous adjustable readings which can be customized for each patient.
They donot have a condylar guidance instead they have receptacles, in which acrylic dough can be contoured to form a customized condylar & incisal guidance.
Can accept the following five records: Face bow, centric jaw relation, protrusive, lateral records, and intercondylar distance record.
They are not commonly used due to their complexity.
A class IV articulator is a fully adjustable articulator
  Examples:-          Pantronic acticulator – Dener (1982)
                               Gnathoscope         - Charls Stuart
                                Denar D 4A & D 5A - Niles Guichet, 1968
                                Simulator (by Ernest Granger)
                                Gnatholator (by Granger)
 
 
BASIC COMPONENT OF AN ARTICULATOR
  • o    Upper member        –  Represent maxilla
  • o    Lower member       –  Represent mandible
  • o    CONDYLAR TRACK –
  • o    CONDYLAR ELEMENT-    
  • o    Vertical Rod  (Incisal Pin)
  • o     Incisal guide table
SOME COMMONALY USED ARTICULATOR
  • o    Mean-Value Articulator
  • o    Hanau wide VUE articulator
  • o    Whip – mix articulator
  • o    Denar articulator
  • o    Panadent articulator
  • o    TMJ articulator  
 
 
 
CONCLUSION
   An articulator is an important device that mechanical analogues the temporomandibular joint & upper and lower dental arches.
 
    A device to which maxillary and mandibular casts can be attached,with the intent of simulating the functional & para functional contact relationships of one arch to the other.

2 comments:

  1. can u send me about research articulator,,,,to more functional..plessss

    ReplyDelete