DENAR® TRACK II SYSTEM - Whip Mix

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16IMMEDIATE SIDESHIFT1. Arbitrary adjustment. Setting thisadjustment to zero provides for tightcoupling of the centric holding cuspsin the position of maximum intercuspation.Increasing the immediate sideshiftadjustment in treatment providesfor greater lateral freedom in the positionof maximum intercuspation.For example:0 mm = tight intercuspation0.5 mm = slight lateral freedom1.0 mm = moderate lateral freedom1.5 mm = greater lateral freedom2. Lateral checkbite method. Condylarpath of movement studies* haveshown that in almost all patients oncethe immediate sideshift has occurredthe orbiting (balancing) condyle movesforward on a path inclined 7° mediallyto the saggital plane (progressive sideshift).*Luncleen, Harry C. and Wirth, CarlG. Condylar Movement PatternsEngrated in Plastic Blocks, Journal ofProsthetic Dentistry, December 1973,pages 870-873.Therefore in this technique, due to inherentdifficulties and potentials for errorin obtaining accurate lateral checkbiterecords and setting the articulator tothese records, more accurate results canbe achieved by assuming the patient hasa progressive sideshift of 7° and usingthe lateral records only to set the immediatesideshifts.When setting the immediate sideshiftadjustment to lateral checkbite records:a. Set both sides of the articulator to thefollowing adjustments:Progressive Sideshift: 7° lockedProtrusive: 30° unlockedImmediate sideshift: 2 mm (screwsturned counterclockwisetwofull revolutions).b. Seat the right lateral checkbite recordbetween the casts with the articulatorin a right lateral mandibular bow position.While maintaining a slight pressureon the bows, rock the left protrusivepath adjustment back and forthuntil the most accurate seating of thecast into the record is achieved. (Thisprocedure must be done very carefullyso as not to modify the record.) Onoccasion you will note that the castwill not seat accurately on the rotatingside. (In this instance, right side.)This is because the patient’s rotatingcondyle may have also moved up ordown and backward or forward as itmoved out and this condylar positionwas reflected in the checkbiterecord. However, seat it as accuratelyas the articulator will allow. To setthe immediate sideshift turn the rightadjustment screw clockwise with thekey provided until the screw headlightly touches the lateral aspect ofthe condylar element. Now removethe checkbite record and lower theincisal pin to disengage the posteriorteeth and lock it in this position. Withthe key provided turn the immediatesideshift adjustment screw clockwiseand count the revolutions required toachieve the most close position. Thethread of the screw provides for 1 mmof immediate sideshift for each complete360° revolution. A quarter turn(90°) represents 0.25 mm of immediatesideshift. Now the measurement hasbeen made and should be recordedon the patient’s record. Resetting the
immediate sideshift to this measurementwill allow the instrument to morefaithfully simulate the immediate sideshiftof the patient. The measurementof the left immediate sideshift is donein the same manner utilizing a left lateralcheckbite record.DISCUSSION: A lateral checkbiterecord is a positional record in that itrecords only one position of the orbitingcondyle. This condylar positionreflects the patient’s unique combinationof any immediate and progressivesideshift movements. However, thereare many combinations of immediateand progressive sideshift articulatoradjustments which can achieve thissame condylar position. In the pastmany articulators had only progressivesideshift adjustments without any provisionfor immediate sideshift movement.When lateral checkbite recordswere used to set such an instrumentthe total sideshift was reflected in thearticulator only as progressive sideshift.One school of thought contendsthat in this usage the cusps tend tobe more tightly coupled in the positionof maximum intercuspation, generallyrequiring more occlusal correction oninsertion of the restoration and thecuspal inclines of the posterior teethtend to be more reduced becauseof the greater progressive sideshiftadjustment.Restorations developed on an instrumentthat produces an immediatesideshift will typically feature a greaterfreedom (and possibly less occlusalcorrection on insertion) in the positionof maximum intercuspation. Inthis usage, since the total sideshift isdivided into immediate and progressivecomponents, the progressivecomponent decreases as the immediatecomponent increases to arrive atthe same condylar position recordedby a lateral checkbite record. Thecontention is that this will result inincreasingly steeper cusps especiallyin the area of the balancing inclines ofposterior teeth on the orbiting (balancing)side.As previously stated, when an articulatorfeaturing both immediate and progressivesideshift adjustments is set tolateral checkbite records, one procedureis to set the progressive sideshiftto the average anatomy dimensionof 7°, and use the lateral records tomeasure only the immediate sideshiftcomponents. The protrusive adjustmentis set to the protrusive checkbiterecords. These articulator settingsare used in diagnostic proceduresand occlusal analysis. In treatmentprocedures the progressive sideshiftadjustments may be increased to 7°+to insure non contact of the balancinginclines (buccal lingual) of cuspson the orbiting side. The greater theincrease in the progressive sideshiftmovementthe greater the clearance ofthese cuspal inclines (ie., a 15° settingwill provide for greater clearance thana 10° setting).17
Page 5: Table of ContentsI. The Track II Ar
Page 10 and 11: 10MEASURING BOW41. earplug2. anteri
Page 12 and 13: FIG. 16FIG. 18FIG. 2012FIG. 17the f
Page 14 and 15: Mounting the Mandibular CastAttach
Page 18 and 19: APPENDIX A-D31AB FACEBOW/EARBOWThe
Page 20 and 21: APPENDIX C-ACCESSORIESIncisal Pins
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DENAR® TRACK II SYSTEM - Whip Mix

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