Gnatho 22-41

Question 1

22. Centric cusp

Answer 1

(also functional cusp)
the bigger, broader and more rounded cusps, which make contacts with 2 cusps of the opposing teeth around the central fossa.
These cusps are known as the centric, centric holding or stamp cusps.
These cusps provide the vertical distance between the mandible and the maxilla. Centric cusps are
the buccal cusps on the lower teeth and
the palatal ones on the upper teeth.

Question 2

23. Non-centric cusps

Answer 2

(also non-functional cusps)
the non-centric or shear cusps are narrower than the centric cusps.
They make contact with only 1 cusp in the opposing dental arch, they support it.
They protect the bucca and tongue during chewing by keeping away soft tissues.
They are
the lingual cusps in the lower arch and
the buccal cusps in the upper dental arch.

Question 3

24. Mesial and distal fossa

Answer 3

is situated at the mesial and distal end of the central groove,
and forms an area slightly wider than the groove near to the marginal ridges.

Question 4

25. Central fossa

Answer 4

a 3rd fossa on the molars in the middle of their occlusal surface,
at the meeting point of the grooves.

Question 5

26. Main/Central groove

Answer 5

runs in mesio-distal direction between the buccal and lingual cusps of the premolars and molars,
also named developmental grooves, since they are formed at the sites where the cusps grow together.

Question 6

27. Supplemental grooves

Answer 6

smaller grooves on the surface of the cusps,

they separate the triangular ridge from the mesial and distal cusp ridges.

Question 7

28. Central fissure

Answer 7

the bottom of the groove is called sulcus or fissure, the one in the central groove is the central fissure.

Question 8

29. Intercuspal space

Answer 8

the triangular area above the groove, between the buccal and oral cusps of a tooth.

Question 9

30. Interocclusal space

Answer 9

the distance between the occluding surfaces of the maxillary and mandibular teeth when the mandible is in its rest position.
There is no contact between the upper and lower teeth (free mandibular position).
The distance between incisors is 2–8 mm, between molars is 1–4 mm,
the distance depends on the bite form (normal, deep bite, etc).

Question 10

31. Physiologic rest position/Rest vertical dimension

Answer 10

the distance between 2 arbitrary selected points
(one of which is on the middle face or nose and the other of which is on the lower face or chin)
measured when the mandible is in the physiologic rest position.
The habitual postural position of the mandible when at rest, in upright position and the condyles are in a neutral unstrained position in the mandibular fossae.
Also called postural position.

Question 11

32. Occlusal vertical dimension

Answer 11

(physical vertical dimension)
the distance between 2 arbitrary selected points
(one of which is on the middle face or nose and the other of which is on the lower face or chin)
measured when the occluding teeth are in maximum intercuspal position.
When the teeth are present it is the uppermost position of the mandible, the distance between maxilla and mandible is the smallest.

Question 12

33. Edge to edge bite

Answer 12

occlusion type, in which the opposing anterior teeth meet along their incisal edges when the teeth are in maximum intercuspation.

Question 13

34. Mandibular prognathism

Answer 13

an overgrowth of the mandible in an anteroposterior direction;
a protrusion of the mandible in relation to the maxillae
the lower front teeth overlap the upper front teeth,
the condition of having a lower jaw that projects beyond the upper part of the face.

Question 14

35. Maxillary prognathism

Answer 14

the upper front teeth are positioned extremely labially related to the lower ones,
their horizontal overlap, the overjet is excessive (4-5mm).

Question 15

36. Deep bite

Answer 15

a dental malocclusion in which the upper front teeth cover the lower more than the normal amount of the overbite – 3mm.
In centric occlusion position, an abnormally large vertical overlap of anterior teeth in centric occlusion.

Question 16

37. Open bite

Answer 16

the lack of contact between the front teeth in any occluding position of the posterior teeth,
there is a space between the upper and lower front teeth,
the patient can’t bite.

Question 17

38. Rest position 1

Answer 17

the mandibular position assumed when the head is in an upright position and the involved muscles, particularly the elevator and depressor groups, are in equilibrium in tonic contraction, and the condyles are in a neutral position in the glenoid fossae

Question 18

38. Rest position 2

Answer 18

the position assumed by the mandible when the attached muscles are in a state of tonic equilibrium.
The position is usually noted when the head is held upright

Question 19

38. Rest position 3

Answer 19

the postural position of the mandible when an individual is resting comfortably in an upright position and the associated muscles are in a state of minimal contractual activity.

Question 20

39. Intercuspal position

Answer 20

the position of the mandible relating to the maxilla which is determined by the opposing cusp/fossa relationship of the masticatory teeth, when the teeth are in complete intercuspation.
This term doesn’t give information about the condylar position, sometimes referred to as the best fit of the teeth regardless of the condylar position —
called also maximal intercuspation.

Question 21

40. Centric relation

Answer 21

according to modern gnathology, centric relation position is
the mandibulo-maxillar relationship in which the condyles articulate with the middle, thinnest avascular portion of their respective disks with the complex in the anterior-superior position against the shapes of the articular eminencies.
This position is independent of tooth contacts.
The discus articularis, which bears the load, has a contact with the anterior, upper surface of the condyle and the articular eminence.
The term refers also to a range of mandibular movement, which is restricted to a purely rotary movement about the transverse horizontal/hinge axis (rotation of the capitulum mandible).

Question 22

41. Retruded contact position

Answer 22

Tooth contact position of the mandible, when the condyles are at their most retruded/distalmost position in the joint cavities.
Not a stable position.
The initial tooth contact usually occurs between the molars.
The condyles are located generally 1-2 mm distally and inferiorly from the centric relation position.