2Ideal Morphologic Occlusion Posterior TeethAngle IContactNormal buccal overjetAnterior TeethAP mm Hor OJVertical mm Ver OB,50%Transverse Midlines aligned
3Ideal Functional Occlusion Intercuspal Position: CR jaw positionSimultaneous posterior contactAxial loading of posterior teethLighter contact of anterior teethAnterior Excursive Guidance:Canine Guidance/ or Group FunctionNonworking: NO contact3. Protrusion: NO posterior contact
6I. Morphologic Variation Brunelle JA et al I. Morphologic Variation Brunelle JA et al.: Prevalence and distribution of selected occlusal characteristics in the US Population, , J Dent Res 1996;75:Third National Health and Nutrition Examination Survey (NHANES III)Age: 8-11 & y/on= 11,000Hx of ortho tx: 20%Crowding: Children 48-58% & Adults 57-67%
7A. Sagittal Plane (Children and Youths) Angle I Normal: 30%Angle I Malocclusion: 55%Angle II Malocclusion: 15%Angle III Malocclusion: 1%
18Skeletal Effect:Canine Guidance: tend to have mandibular plane angle < 24oGroup Function: tend to have a mandibular plane angle > 24o(DiPietro GJ: J Prosthet Dent 38: , 1977; n=112)
192. Nonworking Side Contacts: Nonworking contacts identified in > 60% of a sample (Ingervall B, Archs Oral Biol 17: , 1977)
202. Nonworking Side Contacts: Nonworking interferences (contact only on the nonworking side) identified in 8% of a study sample (Ingervall B, Archs Oral Biol 17: , 1977)
21C. Intercuspal Position Contacts: Ideal Size: small circular areas≤ 1 mm diameterLocation: cusp tips to flat fossae & marginal ridges; or balanced inclines.Number: n=26 or 66
22C. IP Contact Biological Variation (Riise C & Ericsson SG: J Oral Rehabil 10:473-480, 1983.) Size: large irregular areasLocation: on cuspal inclinesNumber: average of 2 contacts/ molar, 1 contact/ premolar and <1 contact/ anterior tooth
23Homo sapiens exhibit greater occlusal variation than any other primate
24III. Biomechanical System Great population variabilityMasticatory system very adaptable to this variation but exhibits greater adaptive capacity with slow developmental change as compared to rapid change, I.e. restorative dentistry.
25III. Biomechanical System Restorative Treatment: We as dentists can not control the biological adaptability but we can control mechanical characteristics. Therefore restorations are fabricated to an ideal occlusion within the scope or extent of the treatment.
26Objectives CR Adjustment: Intercuspal Occlusion Eliminate CR-IP slide, “create new IP in CR”VDO slightly closed from original IP VDOSimultaneous posterior contactAxial loading of posterior teethAnterior lighter contact
27Occlusal Adjustment: A Method Goal: All centric cusps contacting and every posterior tooth pairholding shimstock.