Occlusion Lectures 1-

• straight laterally
• due to geometry of rotation of the working side condyle about its vertical and sagittal axes, AND the arcs of movement of each mandibular cusp about these axes
• usually not a Problem to space the upper guiding cusps to allow the easy tracking of the lower supporting cusps, without introducing ocllusal interferences

embrasures and molar buccal groves

inner

lingual cusps of working side (functional outer aspect of upper supporting cusps against inner occlusal aspects of lower guiding cusps

• reshaping the upper guiding cusps
• no effect on ICP
• contact stability provided that ICP contacts are marked first and only guiding inclines are reshaped.

establish better molar cusp alignment even if distorted from normal anatomy.

• canine: all disclusion provded by canines w absent posterior tooth contacts in laterotrusion when cusps leave their ICP occlusal holding contacts
• group: canines & premolars shared guidance, disclusion in molars, no contralateral side contacts in mediotrusion

modify lower supporting cusps and upper guiding cusps positions & lengths to come into shared guidance contact at the upper bucal cusp to lower buccal cusp position when the casts are held in laterotrusion vs. the standad cone placement to avoid all posterior excursion contact,leaving the canines to provide all the disclusion by canine guidance

• down
• forward
• medially
• non-working side condyle rotates about the vertical and sagittal axes of the working-side condyle in this left lateral jaw movement, AND the arcs of movement of each right side mandibular cusp also rotates about these axes.
• Lower supporting cusps on the right side are tracking out foruard and downwards (which is OK) However they are also tracking MEDIALLY and this places them close to being in opposing contact with the lingual part of the upper right molars: and potential occlusal interference

• inner occlusal aspects of supporting cusp ridges
• ex: opposing triangular ridges
• risk increases with increased curve of Wilson
• 

• 1. 18 Line W for upper (C to M3)
• 2. add line to create lower canine
• 3. divert ICP contacts of upper premolar supporting (lingual cusp to make DISTAL FOSSA CONTACTS) on lower premolars
• 

• laterotrusion side movement
• working side

• mediotrusion
• non-working side

• mandibular cusp that is moving, which is therefore moving in the actual (real) direction that the jaw is moving in. 
• The cusp pathway & jaw are moving in the same direction, ls this a ? right or ? left, or ?protrusive, ? or retrusive, jaw movement

• maxillarycusp that is moving, which is therefore in fact stationary and left behind to track out in the opposite direction to the real direction the Jaw is moving in.
• Therefore the cusp pathway & jaw are moving in the exact opposite directions. Is this a ? right or ? left, or ? protrusive or retrusive

• 40% placement of cusps (to optimize axial loading)
• 60% how the cusps ate going to "get out of there l exit from ICP) without running into or creating eccentric contacts and occlusal intetferences (non-axial forces)
• Think "grooves" rather than just cusps!

• 1. coupled contacts involving opposing supporting cusps
• 2. >3 points of ICP contact involving different planes -not necessarily around a single cusp
• 3. intact dental arch with contacts at right angles to the line of the arch.
• 4. provide single stable end point of jaw closure (aka ICP)

linear alignment

• COUPLED CONTACT
• supporting cusps of lower molars and premolars(buccal cusps) occlude along the central fossa line of the upper teeth
• supporting cusps of upper molars and premolars(lingual cusps) occlude along the central fossa line ofthe lower posterior teeth

relative facial location of the upper lingual cusps and the relative lingual location of the lower buccal cusps(due to the rounding over ofthese cusps) maintains the loading on the teeth axially

no, parabolic form, shouldn't be involved in excursion guidance either

• Easier separation and immediate disclusion from ICP in excursion movements
• Less chance of occlusal interferences
• Less wear due to absence of contact during jaw movement:::
• Axially directed forces
• (hard to get in porcelain)

• zone of ICP contact
• Lack of immediate disclusion* from ICP in excursion movements
• more chance of occlusal interferences
• More wear due to more movement in contact More non axial forces

• 1.  carving with blade shaped instruments
• ghost over cut surfaces with a hot PKT probe instrument to re-melt the wax cusp incline back into a natural parabolic surface and contact again,:.
• 2. Direct restorations
• 3. New castings made against an existing worn occlusion(that has not been therapeutlcally reshaped [to be determined in the diagnostic wax-up stagel
• 4. Relieve occlusal contact (fossa or developmental groove area on cusp tips

• pivoting
• could expose crown margin

• only occluding contactts are on opposing inclines facing same direction
• -> drift

• faster functional and parafunctional wear or holding tips
• receive most eccentric contact
• (common in direct restorations)

cut the canines off the dental casts and examine whether you can put the casts into a single Intercuspal Occlusion, or whether there isc onfusion multiple positions

• cant find ICP
• wide envelope of proprioception feed back

• opposing central fossa line
• alignment facially
• lower molars wider than premolars therefore the lingual cusp tip cones MUST BE PLACED MORE LINGUAL THAN THE PREMOLAR LINGUAL CUSP CONES

non-axial forces (especially with over contoured PFM from insufficient reduction.

form open lingual groove exit-pathway for upper molar ML cusp in laterotrusion

• ML (almost as if mesial molar is premolar)
• occlude along lower central fossa line
• lingual cusp ridge at rt angle with buccal cusp ridge of ML cusp

• distal cusp ridge (wrap around) of ML
• triangualr ridge of DB cusp

• ML cusp triangular ridge
• MB cusp triangular ridge
• oblique ridge

develeopmental groove

pestle & mortar for mastication displacement up out and away from interproximal ebrasures.

• 1. stabilize each tooth (tripoding)
• 2. stable/single most closed end point of jaw closure (ICP)
• 3. ICP loading forces axially
• 4. cusps placed to optimize movement/exit pathways reduce non-axial loading in excursion

• most distal upper molar
• lower central incisionrs

• marginal ridge
• except lower DB which make central fossa and lower 1st D which make distal fossa contact

• fossa
• premolars make D fossa
• molars make central
• excep molar D cusps with make marginal ridge contacts

slightly mesial to make lower D fossa contact

• move mandible distal
• 

reshaping upper guiding cusp inclines

• any tooth contact that inhibits the
• remaining occluding surfaces from achieving stable and harmonious contacts. (In an excursion contact position, anterior guidance would be interrupted by the interference and.transferred to the interfering posterior cusp for disclusion guidance; or be an occlusal contact that interferes with full closure into ICP, or interferes with the closure pathway into ICP'Posterior occlusal interference may encourage recruitment of full closing power of the jaw elevator muscles leading to primary occlusal trauma on the hard and supporting dental tissues' but inonlv a few susceDtible cases to myalgia. Most patients.adapt byalt"ri", th"*f"* position on closure or in the masticatory cycleto avoii an interference in function (e.9. on a new crown)'Avoidance of ICP occlusal interferences may be more difficult than avoiding excursion interferences. Contact patterns during sleep bruxism-may be different. However the notion that occlusal interferences are the etiotogy of bruxism and of TMD, and that TMD should be treated by coronoplasty or other occlusal changes is incorrect,and these are much more complex multifactor disease entities

• shared or mutual occlusal contacts (not at ICP) in a contact jaw movement, that do not disclude the anterior guidance or act as apivoting interference or fulcrum. However, more contacts may mean more occlusal attrition. Eccentric occlusal contacts "every way which way" is a goal oF denture
• Balannd Occluion

condition in centric and^eccentric jaw relation in which there are no interceptive or deflective contacts of occluding surfaces (and there is a progressive gradual disclusion rather than overly steep or abrupt anterior guidance)

• supra-contact interferes with other teeth coming into ICP
• high contacdt in eccentric that interferes with anterior guidance

The resistance permits maximum recruitment of muscle force, which likely produces (non-axial) occlusal trauma to the tooth involved,eld may act as a fulcrum that increases loadon the contralateral TM ,oint + CA!! recruit perticular jaw muscle pain.

• Disclusion is direcdy impaired by an absence of orworn out anterior guidance (loss of disclusion occlusion)
• Careless setting of an articulator
• Creating monoplane occlusions
• Careless placement of supporting cusps, and leaving cusps out of contact (teeth witl rip md rotate over time to re-establish ICP contact but beingh interference in excursion jawmovements