TOPIC: CONCEPT OF OCCLUSION
🎯 KEY FACTS
🔹Farrar appliance is a type of occlusal device which is used to position the mandible anteriorly to treat temporomandibular joint (TMJ) disk disorders.
🔹Condylar guidance of the patient is determined by a protrusive record.
🔹 ‘S’ shaped path of the glenoid fossa determines the path of movement of the condyle and determines the condylar guidance.
🔹In the natural dentition, the centric occlusion is usually 0.5–1 mm anterior to the centric relation.
🔹Concept of lingualized occlusion was proposed by Gysi in 1927, in which the maxillary lingual cusp was used as the dominant element which occluded against the corresponding position of the mandibular teeth.
🔹Reverse articulation is the occlusal relationship in which the maxillary buccal cusps are placed in the central fossae of the mandibular teeth.
🔹Steep inclines are undesirable in complete dentures, as they decrease the stability of the denture by increasing the inclined planes.
🔹In resorbed ridges, the occlusal plane is placed closer to the ridge in order to reduce leverage forces on the denture.
🔹Surfaces of the dentures that affect stability of the dentures are the occlusal, impression and polished surfaces of the denture.
🔹Flat or zero incisal guidance provides maximum denture stability.
🔹Trapozzano’s concept Is also called ‘triad of occlusion’.
🔹Two end factors controlling protrusive movement in the complete denture patients are incisal guidance and the condylar guidance.
🔹In long centric, there is freedom of movement up to 1 mm in the sagittal and horizontal direction.
🔹Mutually protected occlusion is an occlusal scheme in which the posterior teeth prevent excessive contact of the anterior teeth in maximum intercuspation and the anterior teeth disengages the posterior teeth in all mandibular excursive movements.
🔶 Types of Compensating Curves
(i) Anteroposterior curves
– Curve of Spee
(ii) Lateral curves
• Curve of Wilson
• Curve of Monson
• Pleasure curve
🔶Determinants of the incisal guidance are:
• Phonetics
• Aesthetics
• Ridge relationship
• Arch shape
• Ridge fullness
• Inter-ridge space
🔶 Concepts of Balanced Occlusion
• Gysi’s concept (1914)
• French’s concept (1954)
• Sear’s concept (1949)
• Pleasure concept (1937)
• Frush’s concept
• Hanau’s quint (1929)
• Trapozzano’s concept
• Lott’s concept
• Boucher’s concept
• Levin’s concept
🔶 Types of Balanced Occlusion
(i) Unilateral occlusal balance
(ii) Bilateral occlusal balance
(iii) Protrusive occlusal balance
(iv) Lateral occlusal balance