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.
Maxillary incisor proximo-incisal angle from labial view
Maxillary central has mesioincisal angle at nearly right angle.
Maxillary lateral has both mesioincisal and distoincisal angles more rounded than on cetrals.
Mesial contacts are in incisal 3rd, but lateral contacts are more cervical than central.
Only incisor with contact on middle 3rd
Maxillary lateral incisor - distal.
Root to crown proportions of max. incisors
Central root is not much longer than crown.
Maxillary lateral root is relatively longer than on central.
Root shape of maxillary incisors
Maxillary central root is shorter, thicker, cone shaped.
Lateral root more likely to bend distally at apex - central not as likely.
Centrals have triangular shaped cross-section and laterals are more oval.
Maxillary lateral/centrail check which one
onlytooth that can be extracted with rotational force.
Most contacts for all teeth are in
Incisal, junciton of incisal + middle, middle 3rd.
Maxillary incisors from lingual view
Lingual fossa of maxillary incisors - maxillary laterals are more likely to have deeper lingual fossae and pits than centrals.
Cingulum of Maxillary incisors from lingual view
Maxillary central incisor cing. is more developed and off center toward distal. Cingulum of lateral incisor is more centered.
Marginal ridges of maxillary incisors
Max. lateral incisor has the distal marginal ridge appear shorter than mesial due to slope of incisal edge towards distal. This is due to distal placement of cingulum.
Variations in maxillary incisors
Shovel shaped and double shovel shaped. Related to ethnicity.
Accessory (lingual) ridges and grooves possible on maxillary incisors
Present on lingual surfaces on maxillary lateral incisors.
Root shape of maxillary incisors
Root tapers narrower toward the lingual
Proximal view of maxillary incisors
Maxillary central from distal view - you will find that the incisal edge appears to be lingual to midroot axis line. This is due to a bit of a twist to incisal edge on distal half. This is the distolingual twist.
Cervical line of maxillary incisors (prox views)
As on all anterior teeth, mesial CEJ curves more than distal. Largest CEJ curve for all teeth is mesial of maxillary central incisor (up to 3.5 mm).
HOC maxillary incisors prox
Both max. central incisors and lateral incisors have HOCs in cervical 3rd.
Maxillary incisor root - prox
Max. central root has flatter lingual outline in the cervical 3rd, then tapers. Laterals have more overall uniform taper. No root depression on distal, rare shallow depression on mesial.
Root depressions usually on
Distal (not incisors)
Incisal view- crown proportion faciolingually vs. mesiodistally
Both max. incisors have mesiodistal greater than faciolingual, more so for centrals. Laterals are closer to equal for FL and MD
Max. incisor crown outline shape
Max central has a triangular crown outline (flatter facial surface). Max. Lateral has a more round or oval outline.
Incisal ridge contour of max incisors
Max. central has a distolingual twist. Lateral does not.
Max. central has cingulum distal to root midline. Same concepts that vary on how you look at tooth.
Labial contour of max incisors
Max. lateral has more labial curvature (more convex) than central incisor
Crown of mandibular incisors - labial
Mandibular lateral is larger than central.
Flat tooth
Appears wider - shift line-angle to change perception.
Convex surface on tooth
Due to reflected light, appears narrower.
Incisal proximal angles of mand. incisors - labial
Mand. central has mesioincisal angle = distoincisal angle. Lateral has distoincisal angle more rounded than mesioincisal.
Proximal contact areas of mandibular incisors - labial
Mand. central has mesial and distal contact at same level. Mand. lateral has mesial contact more incisal than distal. All contacts in incisal 3rd.
Root to crown proportions of mandibular incisors - labial
Mandibular incisor roots appear to be longer relative to the crown than maxillary incisor roots.
Lingual anatomy of mand. incisors -lingual
All mand. incisors have minimal marginal ridges and fossa depth.
Cingulum of mand. incisors - lingual
Mand. lateral cingulum more distal to midroot axis than on centrals (best seen incisally). Distal marginal ridge shorter than mesial.
Root shape of mand. incisors - lingual
Both mand incisor roots are narrower from lingual and have mesial and distal root depressions. Narrower mesiodistally. Roots taper facial to lingual. Longer faciolingaully than mesiodistally.
Incisal edge of mand. incisors - proximal
Mand. lateral incisor (mesial view) has distolingual corner of the incisal edge showing lingually due to distolingual twist. Centrals do not.
Cervical line on mand. incisors- proximal
CEJ curves toward incisal more on the mesial than distal.
HOC of mand incisors - proximal
Buccal and lingual contours in cervical 3rd. All mand. incisors have smooth lingual surfaces with shallow fossae.
Mand. incisor roots - proximal
Mand roots are much wider faciolingually than mesiodistally. Both mand incisors have mesial and distal root depressions. Both incisors are kidney or bow shaped in cross section.
Crown outline of mandibular incisors - incisal
Mand. central incisors are symmetrical; laterals are not
Incisal ridge contour (alignment) of mand. incisors- incisal.
Lateral incisor has an incisal edge with a distolingual twist; central does not.
Crown proportions of mand. incisors - incisal
All mand. incisors have faciolingual dimension greater than the mesiodistal
Cingulum of mand incisors - incisal
Mand lateral incisor has a cingulum distal to midroot axis. Not central.
Labial contour of mandibular incisors - incisal
Convex facial contour, lingual contour decidedly convex (more curved.
