incisors and k9 Flashcards
permanent incisors function
esthetics, phonetics and mastication (biting, cutting, shearing)
Class traits
characteristics of all incisors
Arch traits
characteristics that distinguish maxillary from mandibular incisors
Type traits
distinguish central from lateral in the same arch
Permanent Maxillary Incisors #
7,8,9 & 10
which crown is larger in maxillary incisors
central incisors
Maxillary Central Incisor – Labial View
Basic geometrical shape trapezoidal
Generally convex mesiodistally and incisocervically
Widest of the incisors
longer incisocervically than it is wide mesiodistally
why is Convexity important to reproduce
so that the teeth are easier to clean and don’t have food traps
Mamelons
rounded protuberances which are present on the cutting edge of an incisor tooth when it first erupts through the gum; are quickly worn away by use.
Imbrication Lines
horizontal striations near the cervix/gingiva that are a result of a change in the growth process
Maxillary Central Incisor – Palatal View
Fossa bounded by 4 convexities (cingulum, marginal ridges, incisal edge)
Mesial marginal ridge is longer than distal marginal ridge
Cingulum offset to the distal to allow room for the incisal papilla
Max central lingual view
- 2 marginal ridges
- 1 lingual fossa
- Cingulum
- MMR>DMR
Maxillary lateral Incisors
▪ Smaller sized – incisal edge slope cervical ▪ to the distal ▪ Rounded angles / MMR>DMR ▪ Pit in lingual fossa ▪ Palatogingival groove ▪ Root tip has distal curvature ▪ Diamond shaped outline
Mandibular Central Incisors
▪ Exhibit symmetry with one another
▪ Show Incisal wear
▪ Longer faciolingually than they are wide mesiodistally
▪ Marginal ridge lengths are the same
Mandibular Lateral Incisors
▪ Slightly wider than central
▪ Have mesial and distal root concavities
▪ Cingulum offset distally
▪ Incisal edge twisted
▪ Both marginal ridges visible in mesial view
▪ Longer MMR than DMR
▪ Distal of incisal edge may be more lingual (distolingual twist)
Canines (6,11 // 22,27)
o Longest of the permanent teeth
o Cornerstones of the arches
o Richest supply of proprioceptive nerve endings
o Crowns are wider faciolingually than mesiodistally
▪ Similar to Mandibular central incisors but different from max
o Functions
▪ Support the lip and facial muscles
▪ Cut or pierce food
▪ Act as guideposts in occlusion illary incisors
Root axis line
from the facial or lingual aspect it divides the root at the cervix into mesial and distal halves; from the proximal aspects it divides the root at the cervix into facial and lingual halves
Maxillary Canine
Longest teeth of the permanent dentition (root apex to cusp tip)
Canine eminence
special projection of bone in the maxilla that houses the long, thick root of the canine
• Anterior to the eminence lies the Incisal fossa and posterior to the eminence lies the canine fossa
Labial View k9 max
- Cusp and cusp ridges make up 1/3 of the incisocervical length of the crown
- The middle labial lobe is called the labial ridge
Lingual View k9 max
- Lingual cusp ridge separates the mesial and distal fossae
- The cingulum is large and centered mesiodistally
- Mesio marginal ridge is longer than the distal marginal ridge
Proximal View k9 max
- Wedge-shaped
- Cusp tip is labial to the root axis line
- Has one root that is very broad faciolingually in cervical third and even more so in the middle third
- The root has mesial and distal depressions – better anchoring
- For maxillary incisors and canines the incisal edge/cusp is either on the root axis line or labial to it… never lingual to it
Incisal View k9 max
- Wider faciolingually than mesiodistally
* Lingual ridge and cingulum visable
Labial View k9 man
- The crown is longer and narrower than the maxillary canine
- The mesial surface is flat and in line with the mesial side of the root
- The cusp and cusp ridges make up 1/5 the incisocervical length of the crown
Lingual View k9 man
- Ridges and fossae not prominent
* Cingulum lies distal to the root axis line
Proximal View k9 man
- For Mandibular incisors/canines the Incisal edge/cusp tip lies either on or lingual to the root axis line… never labial to it
- Almost continuous crown-root convexity on the facial side with minimal crown or root bulge
- Sometimes can have two roots
Incisal View k9 man
- Oblong – longer labiolingually than wide mesiodistally
* Anatomy is less obvious than the maxillary canine