Quiz 4 Flashcards
Forensics
Identification of unidentified or missing individuals, human remains, or victims of mass fatality incidents- teeth for human identification
Inspection of teeth for human identification
Inspection of teeth/jaw legally accepted method for human identification
Aldolph Hitler, Lee Harvey Oswald, Last Czar of Russia
Used in loss of life, plane crashes, fires, explosions (Dr. Faddis-Lori Hacking; plane crash in Moab 8/2008)
Chronological age, dental DNA, bitemarks
Haplodont
Comparative Dental Anatomy
Phylogenetic classes of tooth forms
Single cone ex. alligator
triconodont
Comparative Dental Anatomy
Phylogenetic classes of tooth forms
Three cusps in line in the posterior teeth; largest cusp is the center one, with smaller cusps anteriorly and posteriorly- early mammalian; not seen now except a few breeds of dogs and other carnivores
Quadritubercular
Comparative Dental Anatomy
Phylogenetic classes of tooth forms
4 cusps in a quadrangle
Humans, our relatives- chimps, gibbon, gorilla, and orangutan
Anterior teeth used for incising and holding, posterior teeth used for grinding and shearing
Comparative Dental Anatomy
Phylogenetic classes of tooth forms (stages of tooth evolution)
Graphically there are 4 stages of development: The reptilian stage (Haplodont) Early mammalian stage (Triconodont) Triangular stage (Tritubercular) Quadritubercular molar
Lobes of formation
All show traces of 4 lobes- anterior with 3 labial, one lingual (Can be seen by mamelons )
Anterior teeth lobes and mesial, labial, distal, and lingual
Premolars with 2 lingual cusps- mesial, buccal, distal, mesiolingual, distolingual
Molar lobes are named the same as the cusps
Tooth Form and Jaw Movement
Bunodont and isognathous- tooth bearing cusps, or equal jaw
Anisognathous is unequal jawed
Humans are not perfectly isognathous due to maxillary arch overlapping mandibular; purely up and down movement seen in cats, dogs, pigs (up and down then is typically bunodont)
Lateral movement is seen in extreme in giraffes, camels and ox
more complex movement requires coordination of muscles, teeth, jaws, joints, and bones
Teeth geometry
Teeth show 3 general figures: triangle, trapezoid, rhomboid
Facial and Lingual
All show trapezoid in various dimensions; shortest at base of crown and widest at working surfaces or occlusal line; works so that the interproximal spaces may accommodate the tissues; spacing of the roots allows for enough bone to properly anchor the root; each crown must contact with adjacent teeth to protect gingival tissue during mastication, also for occlusal stability; each tooth has 2 anatogonists in opposing arch- except the mandibular incisor and maxillary 3rd molar
Mesial and distal aspects of anterior teeth
Triangle with base at cervical portion, apex at incisal ridge; have a wide base for crown strength; tapers labiolingual to thin ridge to allow for food penetration
Mesial and distal aspects of maxillary posterior teeth
Trapezoid figures with longest side at base of crown; occlusal is constricted so that the tooth can be forced into the food more easily; otherwise more force would be required in chewing
Mesial and distal aspects of mandibular posteriors
Rhomboid with incline to the lingual; this allows for the cusps to come into proper occlusion, not cusp to cusp
Triangles
6 anterior teeth, maxillary and mandibular - mesial and distal aspect
Trapezoids (longest uneven side)
trapezoid with longest uneven side toward occlusal or incisal surface;
All anterior teeth, maxillary and mandibular - labial aspect, lingual aspect
All posterior teeth- buccal aspect, lingual aspect
Trapezoid (shortest uneven side)
Trapezoid with shortest uneven side toward occlusal surface
All maxillary posterior teeth, mesial aspect, distal aspect
Rhomboid
All mandibular posterior teeth- mesial and distal aspects
Alignment, contacts, and occlusion
When teeth come into contact with opposing teeth, in any functional relation, they are said to be in occlusion
Malocclusion is where there is a deviation in this relation
Restorations- occlusion
Restorations should always be directed in the long axis of the tooth; otherwise will be negative feedback from receptors in the periodontium
Buccal and lingual contours
Buccal and lingual contours have influence in the way food is directed away from gingival tissues; Food impaction, impinging trauma from rough foods; accumulation of dental plaque; over and under contouring of restorations should be avoided
Interproximal form
Proximal contacts of approximating teeth in the arch protect the soft tissue (gingiva) between the teeth and are referred to as interproximal spaces- Leave room for gingival tissue; Correct proximal tooth contacts and marginal ridges- no contacts results in impigment of tissues and food impaction;
gingiva within the interproximal space is called the gingival papilla
Cervical line
The cervical line is a stable anatomical demarcation- the gingival line represents the gingival level on the tooth at any one period in the individual’s life
Misalignment of the teeth may change the gingival line, which is not conducive to the health of tissue; dehiscence is a cleft or partial absence of bone over root
Fenestration is a window in the bone over a root
Cervicoenamel ridge
Curvature of the crown above the cervical line; don’t over or under contour this
Root form
Roots flare for stabilization- cusp tip to cusp tip buccolingually is much less than the buccolingual diameter of the root base; overall form depends on the work the tooth has to do; angle- incisal ridge or cusp is centered over the root
Occlusal curvature
Occlusal plane is curved from anterior to posterior and is called the Curve of Spee
Curvature from mesial to distal or left to right is called the curve of Wilson- lingual inclination of the mandibular molars
Differences between posterior teeth and anterior teeth
Greater buccolingual (faciolingual) measurement compared to mesiodistal; broader contact areas; contact areas more nearly at the same level; less curvature of cervical line mesial and distal; shorter crown cervico- occlusally
Premolars General
4 maxillary/ 4 mandibular;
upper and lower 4,5 in Palmer system; Universal system- maxillary 4,5,12,13
mandibular 20,21,28,29
Premolars (named because anterior to molars) also bicuspids (not proper)
maxillary premolars develop from 4 lobes- same as anterior teeth, and resemble canines when viewed from the buccal; buccal cusp of the first is long and sharp and is used for tearing food; 2nd premolar has a cusp that is less sharp which makes this tooth more efficient in grinding; crown and root are shorter than canine; marginal ridges are more horizontal due to cusp development buccally and lingually thus become part of occlusal surface
Maxillary First premolar overview
2 cusps, buccal and lingual with buccal 1mm longer than lingual; crown is angular with prominent buccal line angles; contact areas mesial and distal are about same level; mesial slope of the buccal cusp is longer than the distal (opposite of canine) most have 2 roots, 2 pulp canals even when only one root found
Maxillary First premolar buccal aspect
Trapezoid shape; The smallest uneven side cervically; very little curvature of cervical line with crest of curve near center of root (convex root wise); mesial outline is concave from cervical line to just above the contact area; mesial slope of buccal cusp is straight, longer than distal slope with possible notch; distal outline is more straight to slightly concave with contact area curve more broad than mesial; distal cusp slope is slightly convex. Mesially, contact area is at middle third while distally, it is occlusally positioned which is an exception from other permanent posterior teeth. width of crown MD is about 2mm less at cervix than at greatest point; buccal cusp is long and fairly pointed before wear; buccal surface is convex showing a strong buccal ridge (max convexity at the cervical 1/3); will be developmental depressions (grooves) mesial and distal to the ridge; root will be 3-4mm shorter than canine; The M and D outline of the root tapers to a pointed apex that is slightly curved distally- if it has 2 roots, the lingual root is hidden behind the buccal root as it’s shorter and narrower than the buccal root; the surface of the root is convex and smooth
Maxillary First premolar lingual aspect
Crown tapers to the lingual, lingual cusp is narrower MD than the buccal; lingual cusp is smooth and spheroidal making the lingual surface convex (M and D convex; max convexity at the middle 1/3); may have a lingual ridge just at the cusp tip; cervical line is a regular curve with slight curve toward root (convex root wise); can see both cusps from the lingual due to the shorter lingual cusp but sharper than the buccal cusp; The D slope of the lingual cusp is longer than the M slope; Apex of the lingual root may be more blunt than the buccal; the M and D outlines of the root taper to a pointed apex that is curved distally; If 2 roots, the lingual root appears shorter and narrower than the buccal root; the surface of the root is convex and smooth
Maxillary First premolar mesial aspect
Shape is trapezoid with longest part at cervical (smallest of the uneven sides is occlusally); tips of cusps are within the confines of the root trunk; B cusp is longer than L cusp by 1mm; wide occlusal table; cervical line may be regular or irregular (regular in outline and curvature is less occlusally ex. 1mm); crest of curvature on the buccal (B outline is convex with max convexity at cervical 3rd) is at junction of cervical and middle thirds; lingual outline is smooth curve from cervical line to cusp tip with crest at middle of middle third (evenly convex); lingual cusp tip is most often in line with lingual border of lingual root;B cusp tip is below the center of B root; L cusp tip is in one line with the L outline of the L root; mesial surface of crown (just cervical to contact area, centered is a depression called the mesial developmental depression that isn’t found on 2nd premolars- this depression extends onto the surface extending and ends at the bifurcation (canine fossa); also found is a groove in the enamel in the marginal ridge in line with the mesial developmental depression, but not connected with and begins in the central groove called mesial marginal developmental groove (crosses MMR and located lingual to the contact area); buccal outline of buccal root is straight with tends toward the lingual; lingual outline of lingual root is fairly straight; root trunk is long (about half of root if 2 roots (80%)) surface is smooth and convex except deep developmental depression below bifurcation; when only one root is found, the developmental depression is found all along the root (the B and L outlines taper to a blunt apex on the center of the crown; the surface is smooth and convex except for a shallow depression in the center that is deeper mesially than distally); contact area is at the middle third and slightly buccal to the midline (BL dimension);
Maxillary First premolar distal aspect
Differs from mesial by: crown surface is all convex with slight flat area cervical to contact area; curvature is less on the distal; don’t have a deep developmental groove crossing the marginal ridge; flat root trunk (with no outstanding developmental signs); bifurcation is abrupt with no (developmental) grooves as found on mesial; curvature of cervical lines is less as compared to mesial surface- it is almost flat
Maxillary First premolar occlusal aspect
Shows a hexagon shape (MB, ML, DL, distal, mesial, DB)
2 buccal sides are almost equal, mesial shorter than distal, ML shorter than DL; thickness is greater than width; the crown is wider bucally than lingually; crest of the distal contact area is more B than the Mesial ;crest of buccal ridge is more distal than the lingual: Elevations (B triangular ridge, L triangular ridge; M &D marginal ridges) Depressions (Central developmental groove, M and D triangular fossa; M marginal developmental groove)
occlusal surface bound by cusp ridges and marginal ridges; M-B and D-B cusp ridge are in line with each other with D-B more B; angle formed by M-B cusp ridge and MMR nears right angle ; angle formed by D-B cusp ridge and DMR is acute; lingual cusp ridges are curved and converge with marginal ridges is a semi-circle ending at cusp tip ; more of the buccal surface is seen from this view than is the lingual surface; will see a central groove going from almost MMR to almost DMM joining mesial marginal developmental groove on the mesial; also have MB and DB developmental grooves; junction of groves is called the M and D developmental pits; just interior to marginal ridges are the M and D triangular fossa; buccal triangular ridge goes from central groove to tip of cusp; lingual triangular ridge goes from groove to tip, but is less prominent; lingual cusp is more pointed than the buccal (more acute)
Maxillary Second Premolar overview
Is more rounded than first and less angular in all aspects; has a single root; will have more variation here than with first premolar; crown usually is smaller in all dimensions than first premolar, but can also be large; root may be as great or even longer than first
First evidence of calcification- 2-2.5 years; enamel completed 6-7 years; eruption 10-12 years; root completion 12-14 years
Maxillary Second Premolar buccal aspect
Buccal cusp may not be as long as the first and is less pointed; mesial slope of buccal ridge is shorter than the distal (opposite of first); crown and root may be thicker at cervical portion than 1st premolar; buccal ridge is less prominent; contact areas ( M-at the junction between middle and occlusal thirds; D- at middle of mid third) buccal and cervical ridges; cervical line is convex root wise; single tampering of root from cervical to apical with a distal curved apex
Maxillary Second Premolar lingual aspect
Lingual cusp is longer than 1st, giving appearance of longer crown (most symmetrical posterior tooth)
(In anterior teeth the mandibular central is most symmetrical)
Maxillary Second Premolar mesial aspect
Trapezoidal geometric outline of crown;cusps are almost same length-Have greater distance between cusp tips giving wider occlusal surface MD; aspect is smooth- no developmental depression is seen on the surface- convex instead; will have a shallow depression on the single root; no deep developmental groove crossing the MMR; MMR is more occlusal than distal one; contact area is broad; Buccal and lingual outlines are slightly convex; buccal crest of curvature between middle and cervical while lingual crest of curvature is middle of middle; cervical line is concave root wise; single root, broad BL with relatively blunt apex; shallow developmental depression
Maxillary Second Premolar distal aspect
similar to M aspect; D contact area is wider and more cervical; DMR is more cervical; straighter cervical line; deeper developmental depression; Distal root depression is deeper than the Mesial depression (opposite of the 1st premolar)- this info needed for perio instrumentation (easy place for calculus to collect- harder to clean)
Maxillary Second Premolar occlusal aspect
Outline of the crown is more rounded- oval rather than angular (usually); central groove is shorter with more supplemental groove radiating out (distal and mesial pits); gives the appearance of a wrinkled look; triangular fossa- near to each other- D is larger and deeper than M; Cusp elevation- both at the same size with wide distance between them; marginal ridges thick strong and well developed;
Maxillary Second Premolar pulp cavities
Buccolingual may 2 canals, buccal pulp horn is most prominent; pulp chamber floor is below cervical level; MD dimension- pulp chamber tapers from occlusal to apical; cervical- kidney shaped; second premolars usually only have 1 root and canal; second has well developed pulp horns - broad chamber BL; MD on 2nd is narrow
Comparison of maxillary 1st and 2nd premolar buccal aspect
1st: M outline concave, while D less concave; M cusp outline- M slope is longer than D- tip is displaced to D; contact ares- M just occlusal to the middle of the middle 1/3 while distal is at the junction between middle and occlusal thirds
2nd: M outline slightly convex, D convex; M slope is shorter than D- tip is displaced to M; contact area- M at the junction between middle and occlusal thirds; D at the middle of the middle thirds
Comparison of maxillary 1st and 2nd premolar lingual aspect
1st: Lingual cusp is shorter 1mm than buccal; tip displaced to M; sharp although the whole lingual surface is convex
2nd: lingual cusp- same length as the buccal; sharp
Comparison of maxillary 1st and 2nd premolar mesial aspect
1st: canine fossa; MM developmental groove; bifurcation level mid root; developmental root depression
2nd: smooth and convex with no depressions; single root, broad; root developmental depression
Comparison of maxillary 1st and 2nd premolar distal aspect
1st: No canine fossa; no MM developmental groove; bifurcation level at the apical third
2nd: similar to M aspect; single broad root; deeper developmental depression on root
Comparison of maxillary 1st and 2nd premolar occlusal aspect
1st: hexagonal outline; B and L cusp elevation; Marginal ridge elevations; long central groove depression; no supplementary grooves; mesial marginal developmental groove; 2 triangular fossa
2nd: oval or rounded outline; B and L cusp elevations; thicker marginal ridges; short central groove depression; supplemental grooves; and 2 triangular fossa
Maxillary first premolar facts
- The lingual cusp of the maxillary premolars is off set to the mesial the first more than the second.
- The non-molar tooth that most frequently exhibits three roots is the maxillary 1st premolar
- The maxillary 1st premolar has the most pronounced developmental marginal groove of any max tooth
- The maxillary 1st premolar is the Posterior tooth that has the greatest cervico-occlusal crown height
- The maxillary 1st premolar has a mesial concavity that makes it difficult to adapt a matrix band
- The premolar that has a longer mesio-facial cusp ridge than disto-facial cusp ridge is the maxillary 1st
- The facial cusp of the maxillary 1st premolar is offset to the distal
- A common trait of maxillary premolars is that their lingual cusps are off set to the mesial
- The premolar with the steepest cusp inclines is the maxillary 1st premolar
- The cervical cross section of the maxillary 1st premolar exhibits a kidney shaped root outline
- The cervical cross section of the maxillary 1st premolar exhibits a kidney shaped pulp chamber floor
- Max 1st premolar only premolar with longer mesial cusp ridge
- Max 1st premolar only tooth with mesial marginal ridge groove and mesial crown concavity and mesial root depression.
- tooth #5 &12 are the non molar teeth having the sharpest demarcation between pulp chamber & canal
Maxillary second premolar facts
- The size and position of the cusps are more identical for the 2nd maxillary premolar than the first
- The maxillary 2nd premolar has two cusps that are of equal height
- Max 2nd premolar symmetrical POSTERIOR tooth
- Max 2nd premolar has cusp heights closer in height to each other than any other PREMOLAR
- Max 2nd premolar has fossa that are closest in size compared to any other posterior tooth
