Occlusion And Articulation Flashcards
Define occlusion and alriculation
- Occlusion is the static relationship between the incising or masticating surfaces of the maxillary and mandibular teeth.
- Articulation – The static and dynamic contact relationship between the occlusal surfaces of the teeth during function.
What’s ideal occlusion?
Many ideal occlusions have been described. In most of these, the maxillary and mandibular teeth contact simultaneously when the condylar processes are fully seated in the mandibular fossae, and the teeth do not interfere with harmonious movement of the mandible during function.
Ideally, in the fully bilateral seated position of the condyle–articular disk assemblies, the maxillary and mandibular teeth exhibit maximum intercuspation.
What’s centric relation?
which is defined as the complete intercuspation of the opposing teeth, this is sometimes considered the best fit of the teeth regardless of condylar position, (Independent of condylar position).
What are points to be considered in occlusion?
- In general the goal in restorative treatment, is to create occlusal contacts in posterior teeth that stabilize the mandibular position instead of creating deflective contacts that may destabilize it.
- And the occlusion should be in harmony with the optimum condylar position, centric relation.
This position is the most musculoskeletally stable position. This we depend on it in ———-cases
• The more recent concept describes a physiologic position in terms of the musculoskeletal relationships of the structures ( centric relation ) , is not a forced position.
What’s forcefully manipulated occlusion?
- —-condyle in highly vascular and innervated retrodiscal tissues (the posterior attachment) posterior to the disc this is frequently an abnormal, forced position
- that could create unnecessary strain in the TMJ. In this circumstance, the disc is displaced anteriorly,
- and clicking of the joint is frequently observed as the patient opens and closes.
What are mandibular movement and their planes
Three-dimensional movement of a body can be defined by a combination of translation (all points within the body having identical movement) and rotation (all points turning around an axis).
Sagittal
Horizontal Plane
Frontal plane
Discuss movements in sagital and horizontal planes
Sagittal terminal hinge axis, perpenddicular to this plane (opening &protrusive)
Horizontal Plane vertical axis perpendicular to this plane working side in the horizontal plane Rotation and translation Bennett movement, or mandibular side shift is frequently present. This may be slightly forward or slightly backward
• Nonworking side condyle travels forward and medially
Finally, the mandible can make a straight protrusive (anterior) movement
Discuss frontal plane movement
lateral movement in the frontal plane, the nonworking condyle moves down and medially, whereas the working condyle rotates around the sagittal axis perpendicular to this plane transtrusion may be observed; as determined by the anatomy of the mandibular fossa on the workiong side, this may be lateral and upward or lateral and downward
What are determinants of mandibular movement?
Mandibular movements are limited by
- posteriorly, the right and left TMJs;
- anteriorly, the teeth of the maxillary and mandibular arches;
- and overall, the neuromuscular system
• The dentist has no control over the posterior determinants, the TMJs; they are unchangeable.
What’s The anterior determinant in mandibular movements?
- The posterior teeth provide the vertical stops for mandibular closure.
- They also guide the mandible into the position of maximal intercuspation, which may or may not correspond with the optimum position of the condyles in the glenoid fossae.
- The anterior teeth (canine to canine) help to guide the mandible in right and left lateral excursive movements and in protrusive movements. • Dentists have direct control over the teeth determinant by: orthodontic movement of teeth; selective grinding, of any teeth that are not in a harmonious relationship (deflecting contact); restoration of the anterior lingual or posterior occlusal surfaces and replace missing teeth.
- Intercuspal position and anterior guidance can be altered, for better or for worse, by any of these means.
Take about The neuromuscular system,
The dentist affect ………..
Through the use of occlusal device or through his role on anterior determinant
- Dentists have indirect control over this determinant through these procedures, which may affect the response of the neuromuscular system through the proprioceptive nerve endings in the periodontium, muscles, and joints, monitors the position of the mandible and its paths of movement ,
- So with successful treatment the dentist perform one of the objectives of restorative dentistry which is : place the teeth in harmony with the TMJs.
- This results in minimum stress on the teeth and joints, with only a minimum effort expended by the neuromuscular system to produce mandibular movements.
study of occlusion and articulation can be broadly categorized as concepts of?
- bilaterally balanced,
- unilaterally balanced,
- and mutually protected articulation.
Current emphasis in teaching fixed prosthodontics and restorative dentistry has been on the concept of mutual protection
Talk about mutually protected articulation
- Also known as canine protected occlusion
- An occlusal scheme in which centric relation coincides with the maximum intercuspation position.
- In this arrangement, The six anterior maxillary teeth, together with the six anterior mandibular teeth, guide all excursive movements of the mandible, and no posterior occlusal contacts occur during any lateral or protrusive excursions.
Talk about Optimum Occlusion
- In closure, the condyles are in the most superoanterior position against the discs on the posterior slopes of the eminences of the glenoid fossae.
- The posterior teeth are in solid and even contact,
- The anterior teeth are in slightly lighter contact.
- Occlusal forces are along the long axes of the teeth.
- In lateral excursions of the mandible, working- side contacts (preferably on the canines) disocclude or separate the nonworking teeth instantly.
- In protrusive excursions, anterior tooth contacts will disocclude the posterior teeth.
What are types of occlusal interferences?
- Centric
- Working
- Nonworking
- Protrusive
