Intra-arch Factors

Question 1

Arch Form

Answer 1

The outline of the arch formed by an imaginary line going through the incisal edges and facial cusp tips and ridges over the ENTIRE length of the arch

Question 2

Describe the typical Arch Form

Answer 2

The posterior segments tend to be straight lines joined by the curve of the anterior group

Question 3

3 types of ANTERIOR part of the Arch Form

Answer 3

1. U-shaped most common
2. V-shaped - when central incisors well ANTERIOR TO the canines
3. Square-shaped - when central incisors and canines are almost in the same line across the frontal plane

Question 4

What is ideal Arch Symmetry

Answer 4

Right and left sides of the arch are MIRROR IMAGES of each other;
Both Right and Left sides of the arch should be the SAME LENGTH

Question 5

Which teeth display the gradual transition from thinner incisor teeth to wider, chunky molars

Answer 5

The canines and premolars

As the canines approach the facial-lingual dimension of premolars

Question 6

Where is the “turning point” of the maxillary arch

Answer 6

At the facial ridge where two angles meet on the labial surface of the canine

Question 7

Where is the “turning point” of the mandibular arch

Answer 7

At the first premolar

Question 8

SIGNIFICANCE OF IDEAL ARCH FORM AND ARCH SYMMETRY I

Answer 8

The streamlining of facial and lingual surfaces’ continuity FACILITATES:

• Atraumatic movement of Lips, Cheeks and Tongue around the Arch
• Mechanical cleansing of enamel surfaces
• Efficient and Stabilising PROXIMAL contacts between adjacent teeth
• A good appearance

Question 9

SIGNIFICANCE OF IDEAL ARCH FORM AND ARCH SYMMETRY II

Answer 9

• Avoids crowding which avoids technical difficulties in restorative dentistry as well as facilitating good management of healthy periodontal conditions.

Question 10

SIGNIFICANCE OF IDEAL ARCH FORM AND ARCH SYMMETRY III

Answer 10

-Ability to DEFINE good Arch Form in detail is required in ortho, prostho and surgical corrections of Arch Form anomalies