Lecture 3 Flashcards
Sulcular Groove
Runs mesiodistally through the posterior teeth in each quadrant. Formed by alignment of most occlusal fossae and central grooves and cusps. From cingulum to incisal edge on down.
Height of contour
Contact areas. If you look at tooth from the proximal view (distal), towards cervical 3rd of tooth there is a bump on the facial and lingual edges. Also facial and lingual heights of contour (look at it from all 4 sides).
Ideal Class 1
Mesiobuccal cusp in mesiobuccal groove in 1st molar.
Class 1
72% of population. This can occur on one side but not the other. Mesiobuccal cusp in mesiobuccal groove in 1st molar. Ideal overbite and overjet, orthognathic profile.
Orthognathic
Ortho = normal, gnathic = jaw.
Class II
22%. Distal occlusion (overbite). Retrognathic profile. If mesiobuccal cusps/grooves don’t match.
Class III
6%. Mesial occlusion. Anterior crossbite. Prognathic profile (mandible forward).
Example
Mesial cusp ridge of distolingual cusp
Incisor
8 in each dentition - 2 per quadrant. Two teath (central and lateral) that are closest to the midline. Mesail surface contacts.
Diastema
Space between central incisors. Frenum (labia frenum) can also attach and not allow teeth to contact.
Primate spaces
In dentition of child. Located mesial of canine and maxillary arch, distal of canine in maxillary arch. Spaces present that allow for permanent teeth growth.
Incisor function
Cut food, articulate speech, support lips (aesthetic), guide mandible during movement (lingual surface guides).
Maxillary central incisors
Longest and widest incisor crown.
Female incisor
More contoured incisors - coloration is affected by race other factors
Male incisor
More rectangular
Developmental Grooves
Facial depressions between lobes of incisors.
Facial incisor characteristics
Relatively straight incisal edge.
Rectangular shape. Longer incisocervically than mesiodistally.
Taper narrower from contact to CEJ.
CEJ curves towards apex.
Root tapers to apex and are longer than the crown.
Lingual incisor characteristics.
Lingual surface narrower (best viewed incisally).
Marginal ridges converge towards cingulum.
Lingual fossa.
Incisor characteristics except for mandibular centrals
Distal crown surface is more convex than mesial.
Mesioincisal line angle is sharper than distoincisal.
Distal contact located more cervically than on mesial.
Incisal edges slope cervically to distal.
Incisor characteristics from proximal view
Wedge shaped outline
HOC in cervical 3rd facially and lingually (cingulum). Lingual outline is “S” shape.
CEJ curves incisally
Root tapers to apex.
Incisal view characteristics
Concave lingual fossa incisal to cingulum.
Incisal edge runs across between widest points on mesial and distal.
Labial outline is broader (less convex) than lingual.
Marginal ridges converge toward cingulum.
Arch traits
Maxillary or mandibular.
Mandibular incisors (vs maxillary).
-Smaller crown.
-Flatter proximal outlines
-Contacts closer to incisal edge.
-Relatively longer roots compared to crowns. (higher number - especially mandibular incisors).
-Relatively wider crowns faciolingually than mesiodistally.
-Smoother lingual surfaces.
-incisal edges that are more likely lingual to midroot axis.
Incisal wear
More incisal ridge faceting on labial of mandibular incisors versus lingual of maxillary incisors.
Maxillary incisor from labial view
- Crown shape of maxillary incisors.
- Maxillary central has wider (2.0), longer (0.5) crown.
- Maxillary lateral is relatively narrower mesiodistally.
- Maxillary lateral is more often missing or peg-shaped.
3rd molar
Most commonly missing.
Lateral incisor
2nd most commonly missed tooth.