15. Gnatology. Physiologic rest position. Masticatory articulation and occlusion. Basic positions of the mandible.

parts of it

what is gnathology

functional/parafunctional jaw movements

physiological rest postition

occulsion/ phys. occlusion/ phys balanced occl.

articulation

basic positiosn of the mandible: central occlusion, max int. position, myocentric occlusion, retruded contact position

centric position (5)

gnathology =

• relation btwn articulation and occlusion of jaws with the teeth

• occluson includes every physiological contact btwn upper and lower teeth

• articulation = movements of lower jaw while functioning (chewing, talkingt etc)

types of movement:

0. the movements of the lower jaw can be functional or parafunctional.

   • -  Functional movements are those that occur while chewing, swallowing, speaking,

     breathing.

   • -  Parafunctional movements are those that occur during grinding or clenching of teeth

     (abnormal function )

P REST POS

• ELEV. AND DEP. GROUPS OF MUSCLES ARE IN EQUILIBRIUM, condyles are unstrained and relaxed

• lips slightly touch each other

• 2-5 mm distance btwn front teeth

occlusion

p occlusion

p balanced occlusion

• dynamic rltnship btwn teeth as mandible goes abt its functional movement - closed teeth - static relationship btwn surfaces of teeth

• p Occlision = occlusion in harmony w mast. system

• p balanced occlusion - a BALANCED occlusion in harmony w TMJ and NM system

articulation (in diff senses)

• in speech, the enunciation of words and sentences

• -  in dentistry, the static and dynamic contact relationship between the occlusal surfaces

  of the teeth during function

centric relation

• maz/mand rsp where condyles articulate in thinnest part of disks

• independent of tooth contacts

• ref point for other jaw movements

• pure rotatory movement around horizontal axis

• In natural dentition, CO often does not coincide with CR—there is usually a slight shift (commonly 1–2 mm anteriorly) as the mandible moves from CR to CO.

family (relations) - WANT TO BE INDEPENDENT FROM THEM, MAX.MAND - RELATION - ROTATORY MOVEMENT RUNNING AWAY, REF POINT AS IN COMPARING FAMILY MEMBERS

centric occlusion

• centric occlusion refers to the maximal bilateral, balanced occlusion of opposing teeth when the mandible in in centric relation

-  due irregularities in the occlusion the centric occlusion is not always perfect

• -  the complete intercuspation of the opposing teeth independent of condylar position,

  sometimes referred to as the best fit of the teeth regardless of the condylar position

myocentruc occlusion

• position btwn centric occlusion and centric relation

• where muscles are constricted uniformly, NOT maximal tonus

• manible is at rest but muscle contractions will raise mandible along myocentric trajectory

4. Retruded contact position:

• rs. occurong at the most retrued postition of the condyles into joint cav’s

• more retrued than centric relation position

• movement towards posterior

centric position

centric posittion = positinon of mandibles when condyles are in centric lrelation