Intro to Dental Terminology // Lecture 1 Flashcards
Homodonts
Animals that have teeth all within the same dentition
Heterodonts
Animals W/ teeth that have different classes
Monophyodont
“Having one set of teeth” (ex beluga whale, deli, porpoise)
Polyphydont
Dentitions w/an endless succession of teeth
(Ex: shark, frog )
Diphyodont
“Having 2 sets of teeth “
Mammals usually have primary (deciduous) and secondary (permanent) dentitions
Humans are :
Diphyodonts and heterodonts
Maxillary arch
Upper jaw
Mandibular arch
Lower jaw
Primary dentition
- ages 2-6
-3 classes: incisors, canines, molars
-20 teeth
-all teeth lost by 12/13
Formula for primary dentition
I 2/2 C 1/1 M2/2 = 5 upper teeth & 5 lower teeth in each quadrant
Secondary dentition
-adults
-32 teeth
- four classes ; incisors, canines, premolars, molars
Formula for secondary teeth
I 2/2 C 1/1 PM 2/2 M 3/3 = 8 teeth per quadrant
Anterior teeth
Incisors and canines
Posterior teeth
Premolars and molars
Universal tooth identification system
Lettered A-T starting at max. right 2nd molar (primary)
Numbered 1-32 starting at max. right 3rd molar (secondary)
FDI FIRST DIGIT
Two digits for each tooth
- first digit = quadrant
1=perm dent, max right quad
2= perm dent, max left quad
3=perm dent, mand left quad
4= perm dent, mand right quad
5= prim dent, max right quad
6= prim dent, max left quad
7=prim dent, mand left quad
8= prim dent, mand right quad
FDI second digit
Tooth position relative to midline
1= central incisor, 8= 3rd molar
Palmer notation system
Ortho & oral surgeons
Four bracket shapes
] = upper right quad
[ = upper left quad
-] = lower right quad
[- = lower left quad
(Letter or number would be in space)
Tooth anatomy overview
Enamel, dentin, cementum are relatively hard (calcified)
Only enamel and cementum normally visible in intact extracted tooth
Enamel
White, protective external surface layer of anatomic crown
Hardest substance in body
95% calcium hydroxyapatite, 5% water & enamel matrix
Develops from ectoderm (enamel organ) and product of epithelial cells called ameloblasts
Cementum
Dull yellow external layer of tooth root
Very thin
65% calcium hydroxyapatite (mineralized and calcified), 35% organic matter (collagen fibers)
Softer than enamel, about as hard as bone
Develops form the dental sac (mesodermal), produced by cementoblasts
Dentin
Hard yellowish tissue underlying enamel and cementum
Major bulk of inner Postino of each tooth crown & root
Visible in radiograph or when tooth has been worn due to decay or restoration process
Harder than cementum, softer & less brittle than enamel
70% calcium hydroxyapatite, 18% organic matter and water
Develops from embryonic dental papilla (mesodermal) and formed by odontoblasts
Pulp
Soft connective tissue in the cavity of the tooth crown& root (pulp cavity) - lots of blood vessels and nerves
Coronal portion = pulp chamber
Root portion = pulp canal or root canal
Surrounded by dentin expect a hole(s) near apex = apical foramen where nerves and blood vessels enter
Develops from dental papilla (mesoderm)
Periodontal ligament
Dark line surrounding tooth between enamel and alveolar bone
Anatomic crown
Part of tooth normally covered by enamel layer
Anatomic root
Part of tooth covered by cementum
Cementoenamel junction /cervical line separates anatomical crown from root
**does not change over patients life
Clinical crown
Amount of tooth visible in oral cavity
** can change over lifetime
Clinical root
Amount of tooth not visible because of gingiva
Patient example; 10 yo with erupting teeth (clinical versus anatomical)
Clinical crown shorter than anatomical; clinical root longer than anatomical
Patient example, 70 yo with gingival recession
Clinical crown longer than anatomical, clinical tooth shorter than anatomical
Facial surface
Surface of a tooth in the mouth resting against or next to the cheeks/lips
Can describe anterior and posterior teeth
Buccal surface
Describes facial surface of POSTERIOR teeth
Labial surface
Describes facial surface of anterior teeth
Lingual surface
Surface nearest to tongue
Palatal surface
Lingual surface of maxillary teeth
Occlusal surface
Chewing surface of posterior tooth
Incisal edge/ridge
On anterior teeth (since no occlusal surface)
Proximal surfaces
Sides of tooth next to an adjacent tooth
Not naturally cleaned by action of cheeks, lips, tongue
Mesial surface
Proximal surface nearest to midline
Distal surface
Proximal surface farther from midline
External line angle
Junction line where two surfaces meet
Replace ‘Al’ with ‘o’
Naming order - mesial, distal, facial, lingual, occlusal/incisal
Point angles
Junctions of three tooth surfaces at a point
Dimension of a tooth
Ex; length of an incisor crown from the incisal edge to the cervical line is called incisocervically
Other examples; mesiodistal, faciolingual, buccolingual, occlusocervical
Length of a root
Could be describes as its cervioapical dimension
Dimensions of crown
When looking from facial, lingual, buccal, mesial, distal ;
Horizontal lines separate cervical, middle, and occlusal/incisal
Root dimensions
Horizontal lines can separate the cervical, middle, and apical thirds
Viewing tooth from facial or lingual
Tooth can be separated with vertical lines that indicate mesial, middle, and distal thirds
Viewing tooth from proximal surfaces
Vertical lines can separate facial, middle, and lingual thirds
Viewing tooth from occlusal or incisal angle
Lines running mesiodistally can separate into facial, middle and lingual thirds
Lines running faciolingually can separate into mesial, middle, and distal thirds
Root to crown ratio
We know the length of a tooth root from the cervical line to the apex( or tip of longest buccal root for teeth with multiple roots)
Normally > 1.0
** clinical significance = tooth with small root to crown ratio is not best for attaching or supporting false teeth
Morphology; elevations and ridges
Elevations = rounded, Ridges= linear
Morphology; elevations and ridges
Elevations = rounded, Ridges= linear
Cusp
Pyramidal elevation/peak on occlusal surfaces/incisal edges
Named based on location
Cusp
Pyramidal elevation/peak on occlusal surfaces/incisal edges
Named based on location
Premolar cusp naming
Buccal or lingual
Molar cusp naming
Named after adjacent line angles; mesiobuccal, distobuccal, mesiolingual, distolingual
Ridges (linear) 4
More subtle= facial
Mesial cusp ridge = extends from the cusp tip toward the mesial surface
Distal cusp ridge extends from the cusp tip toward the distal surface
Triangular ridge = cusp tip to the faciolingual middle of the tooth
Cusp slopes/cusp arms
Mesial and distal cusp ridges
Marginal ridges
On anterior teeth - mesial and distal marginal ridges are located on the mesial and distal border of the lingual surface and converge toward the CINGULUM
On posterior teeth - marginal ridges are located on the mesial and distal borders of the occlusal surface
Triangular ridges
Located on each major cusp of posterior teeth
Extends from a cusp tip towards the depression (suculus) in the middle of the occlusal surface faciolingually
Transverse ridge
When a triangular ridge from a facial cusp joins with a triangular ridge from an adjacent lingual cusp to form a longer ridge
Oblique ridge
When a triangular ridge form a facial cusp joins with triangular ridge from a diagonal lingual cusp to create a longer ridge
Mamelons
Three small tubercles or scallops formed from the three facial developmental lobes on the incisal edges of newly erupted incisors
Perikymata
Numerous minute horizontal ridges on the enamel of newly erupted permanent teeth
Formed from the overlapping of layers of enamel laid down during formation
Closer together in the cervical third of the crown than the incisal third
Developmental grooves
Major, sharply defined narrow linear depressions formed during tooth development; usually separating the lobes of the tooth
Central groove
Located in the buccolingual center of the tooth sulcus
Runs mesiodistally
Fossa developmental grooves / triangular fossa grooves
At the ends of the central groove
Split off toward line angles of the tooth
Named based on which line angles they aim towards
On molars and three cusped premolars ….
Buccal grooves on mandibular = separates mesiobuccal and distobuccal cusps ; central groove to buccal surface
Lingual grooves on maxillary molars = separates mesiolingual and distolingual cusps ; central sulcus onto lingual surface
Supplemental grooves
Additional grooves that are not developmental
Small and irregular grooves on occlusal surface; do not occur at junction of lobes
Fissure
Very narrow cleft or crevice at the depth of any groove
Caused by incomplete fusion of enamel during tooth development
Fossa
Small hollow or depression found between marginal ridges on the lingual surfaces of anterior teeth and at specific locations on occlusal surfaces of posterior teeth
Pits
Occur at the depth of a fossa where two or more grooves join
Root apex
Tip at the end of the root; often with visible openings called apical foramina
Cervix
(Neck) slightly constricted region of union of the crown and root
Root trunk
(Trunk base) part of the root of a multirooted molar or two rooted premolar next to the cementoenamel junction that has not yet split
Furcation
Place on multirooted teeth where the root trunk divides into separate roots
Root trunk dividing
Bifurcation on two rooted teeth
Trifucation on three rooted teeth
Furcal region / interradicular space
Region between two or more roots, apical to the place where the roots divide from the root trunk
Cervical line (CEJ) curvature
Viewing from mesial or distal - cervical line curves toward the incisal or occlusal surface (convex)
Normally curvature is greater on the mesial surface than the distal surface
Curvature greatest for central incisors and lessens moving distally around the quadrant
Mid-root axis line / root axis line
With imaginary line through center of tooth root
Displayed on facial or lingual surface as a line that divides the tooth at the cervix into mesial and distal halves
Displayed on the mesial or distal surface as a line that divides the tooth at the cervix into facial and lingual halves
Height of contour/ crest of curvature on facial/lingual surfaces purpose
Shape and extent of the greatest bulge help determine direction of food particles as they are pushed cervical over the tooth surface during mastication (chewing)
Tooth contours divert food away form the thin free gingiva towards firmer tissues
Height of contour on facial/lingual surfaces
Anterior teeth = facial and lingual heights of contour in the cervical third of the crown
Posterior teeth = HOC on the facial surface in the cervical third of the crown and HOC on the lingual in the middle third of the crown
Contact areas / proximal heights of contour PURPOSR
Greatest heights of contour on the proximal surfaces
-stabilizes the position of teeth within each arch
-prevent food impaction
-protects the interdental papillae of gingiva by diverting food buccally and lingually
Diastema
Space that exists between two adjacent teeth in the same arch that is not the result of a missing tooth
Contact areas general guidelines
When viewing from facial:
—contact areas are either in the incisal third, the junction of incisal and middle thirds, or in the middle of the crown
-on most teeth the distal contact is more cervical than the mesial
-mesial contact areas on central incisors are most incisal, contact areas on molars are more cervically
When viewing from incisal/occlusal:
-contacts on anterior teeth are nearly centered faciolingually
-contacts on posterior teeth are often located slightly to the facial of the tooth midline buccolingually
Embrasure spaces
V shaped open space formed by the curved tooth surfaces that sweep away from proximal contact areas
4 types - interproximal, occlusal/incisal, facial, lingual
Interproximal space
Cervical to the contact area and between two teeth
Incisal/ occlusal embrasure
Widen occlusally from contact area; area between the marginal ridges on two adjacent teeth and the occlusal to their contact area
Where we place floss before passing it through contact area to clean tooth surfaces in interproximal space
Lingual embrasure
Widen lingually from contact area
Buccal embrasure
Widen buccally/facially from contact area
Interdental papilla
Projection of free gingival tissue; resides cervically to each proximal contact
In healthy mouths, forms a triangular shape from the facial view but resembles a slightly sagging test from proximal view ( called the col)
Embrasure spaces key points
Lingual embrasure is usually larger than facial
-most teeth narrower on lingual side than facial side
-contact pints are located facial to the faciolingual midline of the crown
Occlusal or incisal embrasure is usually shallow from the occlusal surface to the contact areas and is narrow faciolingually on anterior teeth but broad on posterior teeth
Embrasure spaces key points
Lingual embrasure is usually larger than facial
-most teeth narrower on lingual side than facial side
-contact pints are located facial to the faciolingual midline of the crown
Occlusal or incisal embrasure is usually shallow from the occlusal surface to the contact areas and is narrow faciolingually on anterior teeth but broad on posterior teeth
