Tooth morphology revision PDF

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TOOTH MORPHOLOGY REVISION NOTES...

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Tooth morphology progressional test  all teeth are made up of a crown and one or more roots.  The crown may have a chisel like edge or one or more points called cusps Four basic teeth in permanent dentition  Incisors= horizontal incisor edge  Canines= single large cusp  Premolars= 2 cusps varying in size  Molars= with 4/5 cusps. There are 32 teeth in total in the adult dentition. There are 8 teeth in each quadrant if the third molars have erupted.  

Permanent teeth are number 1-8. Central incisor=1 3rd molar=8 Deciduous teeth are number A-E. central incisor=A 2nd deciduous molar=E

Maxillary Central permanent incisor  FDI= 11(right), 21(left)  Alpha numeric UR1, UL1  Largest crown  When viewed labially it has a smooth surface and usually slightly convex.  The mesio-incisal angle is sharp  The disto-incisal angle is more rounded  The lingual surface is concave with mesial and distal marginal ridges which meet at the neck (cervix) of the tooth forming a convex cingulum  When viewed mesially or distally the crown appears wedge shaped  It has one tapering root  Only one root canal but 2 pulp horns (cornua), one mesial one distal. Chronology Initial calcification=34mths Crown completion=4-5yrs Eruption into occlusion= 7-8yrs Root completion=10yrs

Maxillary lateral(second) incisor

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FDI= RHS 12 LHS 22 Not as rectangular as the central incisor Mesio-incisal edge is sharper Less bulky, more slender tooth Crown appears wedge shaped when viewed mesially or distally. The lingual surface has 2 pronounced marginal ridges Where the ridges meet at the cervix they enclose a depression or fossa One tapered root which is more flattened One root canal with 2 pulp horns, mesial and distal

Chronology Initial calcification= 1012mths Crown completion 45yrs Eruption into occlusion=8-9yrs Root completion= 11yrs

Maxillary canine  FDI=RHS13 LHS23  The crown comes to a point or cusp at the incisal surface.  The labial surface is convex  Has a mesial/distal slope (distal slope is longer)(mesial slope is shorter)  Distal surface is more bulbous than the mesial surface  The lingual surface has marginal ridges  Large cingulum and a mesial and distal fossa  One long tapered root  One root canal  No pulp horn. The distal groove is more prominent than the mesial

Chronology Initial calcification=45mths Crown completion=67yrs Eruption into occlusion= 1112yrs Root completion=1315yrs

Maxillary 1st premolar  FDI= RHS14 LHS24  The crown has 2 cusps, 1 buccal and one lingual  Buccal cusp is larger  The mesial slope is longer than the distal slope  When viewed mesially a groove can be seen between the 2 cusps and a depression between the roots known as the canine fossa which reaches to the cervical margin.  The crown is flattened mesio-distally and the cusps sit directly above the root.  Has 2 roots one buccal and one lingual (these can be fused)  Has 2 root canals and two pulp horns

Chronology initial calcification=18-21 mths crown completion=5-6yrs eruption into occlusion=10-11yrs root completion=12-13yrs

Maxillary 2nd premolar  FDI= RHS15 LHS25  It as 2 cusps one buccal and one lingual  The buccal cusp is slightly larger  The mesial slope of the buccal cusp is shorter than the distal slope  The lingual cusp is displaced mesially like the 1st premolar  The crown is flattened mesio-distally and the cusps sit directly above the root  Only one root which is flattened mesio-distally  There may be one or two root canals and two pulp horns  Roots may bend distally at the apex

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More prominent groove on the distal side

Chronology Initial calcification=2-2.5yrs Crown completion=6-7yrs Eruption in occlusion=10-12yrs Root completion=12-14yrs

Maxillary 1st molar  FDI= RHS16 LHS26  Has 4 cusps- mesio-lingual, mesio-buccal, disto-lingual & disto-buccal  The crown is an equilateral rhomboid shape  Sometimes a 5th cusp is present on the lingual surface of the mesio-lingual cusp (cusp of Carabelli)(mesial palatal cusp)  Has 3 roots one lingual and 2 buccal

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The mesio-buccal root is wider at its junction with the lingual root, than the distobuccal root. It has 3 root canals and four pulp horns

Chronology Initial calcification= birth Crown completion= 2.5-3yrs Eruption into occlusion=6-7yrs Root completion=9-10yrs

Maxillary 2nd molar  FDI= RHS17 LHS27  Has 4 cusps- mesio-palatal, mesio-buccal, disto-palatal & disto-buccal  Disto-lingual cusps is smaller than that of the 1st molar  The crown is not an equilateral rhomboid shape  Has 3 roots, one lingual and 2 buccal  The mesio-buccal root is wider than the disto-buccal root at the junction with the lingual root  Has 3 root canals and three/four pulp horns depending on the number of cusps Chronology Initial calcification=2.5-3yrs Crown completion= 7-8yrs

Mandibular central incisor  FDI= LHS31 RHS41  Flat crown almost symmetrical  The disto-incisal angle is rounder than the mesio-incisal angle.  Crown appears wedged shaped  Lingually there are faint marginal ridges and a small cingulum.  One root  The mesial and distal surfaces are grooved, the distal groove being more pronounced than the mesial grove.  Has one root canal and a mesial and distal pulp horn. Chronology Initial calcification= 3-4mths Crown completion=4-5yrs Eruption into occlusion= 6-7yrs Root completion= 9yrs

Mandibular lateral (second) incisor  FDI= RHS42 LHS32  Crown is more fan-shaped than the central incisor  The mesio-incisal angle is sharp, and the disto-incisal angle  The mesial side is longer than the distal side.  Crown is wedge-shaped and leans lingually  One root, one root canal, and two pulp horns- one mesial one distal Chronology Initial calcification= 3-4mths Crown completion=4-5yrs Eruption into occlusion= 7-8yrs

Mandibular canine  FDI= RHS43 LHS33  Less bulky than upper canine  The crown is tall compared to its width, is smooth,  Has a single cusp which inclines distally  The mesial slope is shorter than the distal slope and the distal surface is more bulbous than the mesial surface.  The marginal ridges and cingulum are less pronounced  Two lingual fossae the distal being the greater of the two  One root, flattened mesio-distally with a mesial and distal groove, the distal usually the more prominent. Chronology  One root canal and no pulp horns. initial calcification= 4-5mths crown completion= 6-7yrs eruption into occlusion= 9-10yrs root completion= 12-14yrs

Mandibular 1st premolar  FDI= RHS44 LHS34  The crown comprises two cusps  Large buccal cusp and a smaller lingual cusp  From the buccal view the mesial slope is shorter than the distal slope.  The overall crown for both lower premolars is much rounded compared to the squashed shape of the upper premolars

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The occlusal surface shows a rounded outline distally and a chamfered outline mesially with a developmental groove interrupting the mesio-lingual marginal ridge There are two fossae, one mesial one distal the distal one being the larger of the two. This tooth is single rooted and somewhat triangular with rounded angles and mesial and distal grooves. It has one root canal and one buccal pulp horn

Chronology Initial calcification= 1.5-2yrs Crown completion=5-6yrs Eruption into occlusion=10-12yrs one or two smaller Root completion= 12-13yrs

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there are two lingual cusps the mesio-lingual cusp will be larger of the two. When viewed buccally the crown has one cusp where the mesial slope is shorter than the distal slope. The mesial marginal ridge is higher than the distal marginal ridge. The buccal cusps leans lingually and the lingual cusps overhang the root The occlusal outline is rounded when there is only one lingual cusp. The occlusal outline will be more angular when a second lingual cusp is present Single rooted The root can bend distally to the apex There is one root canal and a pulp horn to each cusp.

Chronology Initial calcification= 1.25-2.5yrs Crown completion= 6-7yrs Eruption into occlusion= 11-12yrs Root completion= 13-14yrs

Mandibular 1st molar  FDI= RHS46 LHS36  Crown consists of five cusps, 3 cusps on buccal side-mesio-buccal, centro-buccal, disto-buccal.  2 cusps on the lingual side- mesio-lingual, disto-lingual  The mesial marginal ridge is higher than the distal marginal ridge.  When viewed mesially the buccal cusps lean lingually and the lingual cusps tend to overhang the root.  The lingual cusps are more pointed than the buccal cusps  It has two roots, curved distally-one mesial and one distal.  Both roots are flattened mesio-distally.  The mesial root is broader.  Has 2 sometimes 3 root canals and a pulp horn to each cusp Chronology Initial calcification= at birth Crown completion=2.5-3yrs Eruption into occlusion=6-7yrs Root completion= 9-10yrs

Mandibular 2nd molar  FDI= RHS47 LHS37  Has 4 cusps, 2 buccal and 2 lingual  The lingual cusps are higher than the buccal cusps  From the mesial or distal aspect, the buccal cusps lean lingually  Occlusal outline is rectangular with a cusp at each corner

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It has 2 roots that are closer together Has two or three root canals It has one pulp horn per cusp

Chronology Initial calcification=2.5-3yrs Crown completion= 7-8yrs Eruption into occlusion= 12-13yrs C Root completion= 14-15yrs Outline form (shape) of crown from the occlusal (posterior teeth), labial (anterior teeth) and interproximal view(s). Cuspal Form; the number, position, shape and relative size of the cusps Incisal Form; the shape of the incisal edge(s) and incisal corners Pits (fossae) and grooves number and position. Fissure Pattern on occlusal surface posterior teeth.

Oval outline: with central fissure, connecting mesial & distal pits/ fossae

Rounded outline: with a mesial and distal pit/ fossa

Pentagon outline

Rhomboidal outline

Pentagon outline 5 cusp Mandibular First Molar

Rectangular/oblong outline Mandibular Second molar

Rhomboid outline Maxillary First/Second molar

Heart- shaped outline 3 cusp Maxillary molar when DP cusp absent

Maxillary central incisor Large chisel-shaped, trapezium

Maxillary lateral incisor Blade shaped, narrower trapezium

Maxillary canine Large irregular pentagon

Maxillary central incisor proximal view Wedge or triangular

Mandibular canine long pentagon

Mandibular first incisor Symmetrical narrow trapezoid

maxillary canine proximal view wedge

Mandibular lateral incisor Narrow trapezoid

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