Development of the Occlusion Flashcards
What is normal occlusion
An occlusion that satisfies the requirements of function and aesthetics but in which there may be minor irregularities of individual teeth.
What are gum pads
The structures that represent dental arches at birth
Which gum pad is wider and longer
Upper gum pad
What do the segmented elevations in gum pads represent
Unerupted teeth
What and when are the first teeth of the deciduous dentition erupted
Lower central incisors
6-12 months
What and when are usually the first permanent teeth to erupt in the mixed dentition
The first molars
6years ish, +/- 12 months
Do the permanent incisors erupt labially or palatally to the deciduous incisors
Palatally
How is the increased width of the erupting permanent incisors accommodated for
- Pre-existing spacing
- Proclination
- Growth (increased inter-canine width)
What is the leeway space
The difference between the combined mesio-distal widths of c, d & e compared to 3, 4 & 5
What is the usual leeway space of the lower and upper arches
- Lower arch: 2mm per quadrant
- Upper arch: 1mm per quadrant.
What guides the permanent molars into place
The terminal plane formed by the E’s, currently into class 2 relations
What allows the permanent molars into class 1 relations
After the loss of the E’s the greater leeway space results in the first molars drifting forwards into class 1 relation
What does the mesio-buccal cusp of the 1st maxillary molar occlude with
The mid-buccal groove of the mandibular first molar
What does the lower incisal edge occlude with
The cingulum plateau of the upper incisors
What teeth provide anterior and canine guidance
Incisors provide anterior guidance in protrusion with the disclusion of posterior teeth
Canines = canine guidance in lateral excursion and ensures no interferences on the non-working side
