Gnatho 42-63

Question 1

42. Centric occlusion

Answer 1

Tooth contact position when the jaw and the condyles are in centric relation and there is intercuspidation between the opposing teeth.
This may or may not coincide with the maximal intercuspal position.

Question 2

43. Frontal edge to edge bite

Answer 2

the position of the mandible, when the upper and lower edges of the incisors meet along with their incisal edges, when the mandible is in an anterior/propulsive position.

Question 3

44. Lateral cusp bite position

Answer 3

Due to the lateral movement of the mandible on the working side the cusps of the lower and upper molars occlude, while, in ideal situation, on the nonworking side there is no occlusion.

Question 4

45. Maximum mouth opening position

Answer 4

It is the position of the lower jaw, where the distance is the biggest between the incisal edges of the upper and lower incisors.
In this case the condyles in the TMJs get out from their central position.
Through translation and rotation the condyle moves down and frontal direction driven by the tuberculum articulare and limited by the surrounding tissues.

Question 5

46. Maximum intercuspal position

Answer 5

When most of the teeth have a contact with the teeth of the opposing arch, independently from the position of the condyles.
The condyles are not always in their centric position in their articular fossae, although it would be the optimal position.

Question 6

47. Propulsion

Answer 6

Propulsion/moving forward is a translational, symmetric movement in the median sagittal plane.
The total propulsive path starts from the retruded contact position, passes through the intercuspal position and edge to edge occlusion and ends in the protruded contact position.
In the case of normal overbite the lower incisors run against the upper front teeth during propulsion, therefore the further propulsion is possible only with a slight opening of the mandible at the same time.
During propulsion the condyles move anteriorly and inferiorly on the slopes of the articular eminences, symmetrically on both sides.
Ideally the incision inferius moves straight forward without any lateral movement.

Question 7

48. Repulsion

Answer 7

opposite movement of propulsion,
a backward movement, it starts from the maximal protrusive position of the mandible; it goes till the intercuspal position.
Protrusion and retrusion are guided movements,
condyles move symmetrically in the two joints backward and a little upward.
Ideally the incision inferius moves straight backward without any lateral excursion.

Question 8

49. Retropulsion

Answer 8

movement of the mandible from the intercuspal position to the retruded contact position.

Question 9

50. Working side

Answer 9

the side toward which the mandible moves during lateral excursion.

Question 10

51. Non-working side

Answer 10

that side of the mandible that moves toward the median line during lateral excursion.
Normally there is a gap between upper and lower teeth on the non-working side.

Question 11

52. Bennett movement

Answer 11

The lateral shift of the mandible during lateral movement is called as the Bennett movement,
which is defined as the bodily shift of the mandible toward the working side during lateral excursion.
A pure lateral movement of the mandible, when the working condyle only rotates around its vertical axis, occurs extremely rarely.

Question 12

53. Saggital symphysis path

Answer 12

Movement of the incision inferius, I point in the saggital plane

Question 13

54. Saggital condylar path

Answer 13

During the symmetrical movements of the jaw (propulsion and opening) the ectocondylare moves forward on concave pathway opened cranially, which has a radius ~20mm.
The length of this path is about 15mm.

Question 14

55. Lateral symphysis path

Answer 14

moveement of the incision inferius, I point in the horizontal plane.

Question 15

56. Lateral condylar path

Answer 15

that path traveled by the mandibular condyle in the horizontal plane during various mandibular movement.

Question 16

57. Occlusion

Answer 16

it means any contacts between upper and lower teeth;
this term means either a contact between one pair of teeth, or one group of teeth or the whole upper and lower dentition.
The static relationship between the incising or masticating surfaces of the maxillary or mandibular teeth or tooth analogues.

Question 17

58. Inocclusion

Answer 17

there is no contact between upper and lower teeth.

Question 18

59. Non-Occlusion

Answer 18

a kind of malocclusion, for example in intercuspal position there is no occlusion between one or more teeth.

Question 19

60. Disclusion

Answer 19

separation of the upper and lower teeth during any movements of the mandible

Question 20

61. Tooth guidance

Answer 20

the occlusal/incisal surface of the teeth direct and at the same time limit the mandibular movements.
A particular surface of a tooth directs one movement, another surface directs another movement.
The movements in different directions can be guided by one tooth or a group of teeth, while the other teeth have no contact.
We differentiate incisor, canine and group guidance.

Question 21

62. Incisor guidance

Answer 21

During protrusion, the incisal edge of the lower incisors moves forward and downward on the palatal surface of the upper incisors, therefore this surface directs and limits the movement of the mandible, while there is no contact between the upper and lower cuspal teeth.

Question 22

63. Canine protected articulation

Answer 22

a form of mutually protected articulation in which the vertical and horizontal overlap of the canine teeth disengages the posterior teeth in the excursive movements of the mandible.
During lateral movement of the mandible the edge of the lower canine moves lateral and downward on the palatal surface of the upper canine,
therefore this surface directs and limits the movement of the mandible,
while the contact between the upper and lower cuspal teeth on the non-working side is disengaged.