Harvard School of Dental MedicineHarvard School of Dental MedicineDepartment of Restorative DentistryDepartment of Restorative Dentistry

Dental TerminologyDental Terminology

Predoctoral Curriculum in DentistryPredoctoral Curriculum in DentistryDiagnosis and Prevention Block 2002Diagnosis and Prevention Block 2002

Msd Fábio TunesMsd Fábio Tunes

Dental Terminology - Why ?Dental Terminology - Why ?

Maxillary and Mandibular TeethMaxillary and Mandibular Teeth

The portion of the jaw that The portion of the jaw that supports the teeth is called supports the teeth is called the the alveolar processalveolar process. The . The bony socket in which the bony socket in which the root fits is called theroot fits is called thealveolusalveolus. . Teeth in the upper jaw are Teeth in the upper jaw are called called maxillary teethmaxillary teeth. In. Inthe lower jaw they arethe lower jaw they arecalled called mandibular teethmandibular teeth..

Tooth EruptionTooth EruptionThe crown portion of the tooth erupts through the The crown portion of the tooth erupts through the boneboneand and alveolar ridge mucosaalveolar ridge mucosa. The tooth continues to erupt. The tooth continues to eruptfrom the bone and surrounding oral mucosa, now from the bone and surrounding oral mucosa, now called called gingivagingiva..

Crown and RootCrown and Root

EruptionEruption of a tooth is thus moving of the tooth through of a tooth is thus moving of the tooth through its surrounding tissues so that the its surrounding tissues so that the clinical crownclinical crown gradually appears longer.gradually appears longer.

Crown and RootCrown and Root

Each tooth has a Each tooth has a crowncrown and and rootrootportion. The crown is covered withportion. The crown is covered withenamel, the root is covered with enamel, the root is covered with cementumcementum. Crown and root are . Crown and root are joined at the joined at the cemento-enamel cemento-enamel junctionjunction, also called the , also called the CEJCEJ. The . The line that demarcates it is called the line that demarcates it is called the cervical linecervical line..

Crown and RootCrown and RootThe The anatomical crownanatomical crown is the is the whole crown of the tooth whole crown of the tooth that is covered by enamel, that is covered by enamel, whether erupted or not. The whether erupted or not. The clinical crownclinical crown is only that is only that part seen above the gingiva. part seen above the gingiva. Therefore, if the anatomicalTherefore, if the anatomicalcrown does not fully erupt, the crown does not fully erupt, the part that is visible is consideredpart that is visible is consideredthe clinical crown, and the un-the clinical crown, and the un-erupted portion is part of the erupted portion is part of the clinical rootclinical root..

Crown and RootCrown and RootThe root portion may be The root portion may be single or multi-rootedsingle or multi-rooted with a with a bifurca-bifurca-tiontion or or trifurcationtrifurcation, i.e., division of the root portion into two, i.e., division of the root portion into twoor three roots. Each root has one or three roots. Each root has one apexapex, or terminal end. The, or terminal end. Theroot portion is held in its position relative to the other teeth inroot portion is held in its position relative to the other teeth inthe the dental archdental arch by being firmly anchored in the bony by being firmly anchored in the bony alveolar alveolar process process of each jaw.of each jaw.

BifurcationBifurcation

TrifurcationTrifurcation

AlveolarAlveolarProcessProcess

AAAA

Dental TissuesDental Tissues

– EnamelEnamel– DentinDentin– CementumCementum– PulpPulp

EnamelEnamel• Most densely mineralized and Most densely mineralized and

hardest tissue in the human body.hardest tissue in the human body.• 96% unorganic and 4% organic 96% unorganic and 4% organic

matter and water.matter and water.• Forms the outer surface of the Forms the outer surface of the

anatomic crown.anatomic crown.• Thickest over the tip of the crown,Thickest over the tip of the crown,

becomes thinner as it approachesbecomes thinner as it approaches the cervical line.the cervical line.• Color varies with thickness and Color varies with thickness and

mineralization.mineralization.

DentinDentin

• Dentin forms the main portion or Dentin forms the main portion or body of the tooth (crown and body of the tooth (crown and root)root)

• It is wrapped in an envelope of It is wrapped in an envelope of enamelenamel that covers the crown, that covers the crown, and an envelope of and an envelope of cementum cementum that covers the root.that covers the root.

DentinDentin

• Hard, dense, calcified tissue; softer Hard, dense, calcified tissue; softer than enamel but harder than bone or than enamel but harder than bone or cementum.cementum.

• Chemical composition is 70% Chemical composition is 70% inorganic and 30% organic matter and inorganic and 30% organic matter and water.water.

• Appears yellowish, has elasticityAppears yellowish, has elasticity• Unlike enamel, dentin is capable of Unlike enamel, dentin is capable of

adding to itself adding to itself ((secondary dentin, secondary dentin, reparative dentin)reparative dentin); ; dentin-forming cells dentin-forming cells = = odontoblastsodontoblasts

DentinDentin

• • Reparative DentinReparative Dentin:: Is the dentin laid down in response to Is the dentin laid down in response to caries or trauma.caries or trauma.

• • Secondary DentinSecondary Dentin:: Is the dentin that continues to be laid Is the dentin that continues to be laid down in the pulp chamber after tooth down in the pulp chamber after tooth eruptioneruption

CementumCementum• Bone-like substance that covers the root.Bone-like substance that covers the root.• Main function is to provide a medium for Main function is to provide a medium for

attachment of the tooth to the alveolar attachment of the tooth to the alveolar bone as part of the bone as part of the periodontiumperiodontium

• Not as dense or hard as enamel or dentin Not as dense or hard as enamel or dentin but is denser than bone to which it bears but is denser than bone to which it bears physiological resemblance.physiological resemblance.

• The chemical composition is 45% to 50% The chemical composition is 45% to 50% inorganic and 50% to 55% organic inorganic and 50% to 55% organic components.components.

CementumCementum

• The union of cementum and dentin is The union of cementum and dentin is called the called the dentino-cemental junctiondentino-cemental junction..

• 2 types of cementum:2 types of cementum:A)A) cellularcellular - confined to the apical - confined to the apical

1/3 of root and can reproduce 1/3 of root and can reproduce itself.itself.

B)B) acellularacellular - covers the entire - covers the entire anatomical root.anatomical root.

• Cementum as dentin continues to be Cementum as dentin continues to be formed after tooth eruption by formed after tooth eruption by cementoblastscementoblasts

PulpPulp

• The pulp is the nourishing, The pulp is the nourishing, sensory, and dentin-sensory, and dentin-reparative system of the reparative system of the tooth.tooth.

• Composed of blood vessels, Composed of blood vessels, lymph vessels, connective lymph vessels, connective tissues, nerve tissues, and tissues, nerve tissues, and dentin formation cells dentin formation cells (odontoblasts)(odontoblasts)

PulpPulp

• Pulp is housed in the Pulp is housed in the center of the tooth within center of the tooth within the dentin surrounding the the dentin surrounding the pulp tissue.pulp tissue.

• The walls of the pulp cavity The walls of the pulp cavity are lined with odontoblasts. are lined with odontoblasts. Their chief function is to Their chief function is to lay down primary and lay down primary and secondary dentin.secondary dentin.

PulpPulp

• Anatomically the pulp Anatomically the pulp chamber is divided into chamber is divided into two areas:two areas:1)1) The The pulp chamberpulp chamber

in the coronal in the coronal portion of the tooth.portion of the tooth.

2)2) The The root (pulp) root (pulp) canalscanals in the roots in the roots of the tooth.of the tooth.

• Pulp chamberPulp chamber and and root root (pulp) canals(pulp) canals = = pulp pulp cavitycavity..

Types of TeethTypes of Teeth

• Anterior Teeth:Anterior Teeth:– IncisorsIncisors– CaninesCanines

• Posterior Teeth:Posterior Teeth:– PremolarsPremolars– MolarsMolars

Types of TeethTypes of Teeth

• Functions of teeth vary. Functions of teeth vary. • Tooth shapes and sizes differ with their Tooth shapes and sizes differ with their

location in the jaws. location in the jaws. • The three basic functions of teeth are The three basic functions of teeth are

cutting, holding or grasping, and grinding.cutting, holding or grasping, and grinding.

IncisorsIncisors

• Eight incisors total:Eight incisors total: 2 maxillary centrals (LI) 2 maxillary centrals (LI) 2 maxillary laterals (CL)2 maxillary laterals (CL) 2 mandibular centrals (ci)2 mandibular centrals (ci) 2 mandibular laterals (li) 2 mandibular laterals (li)

• Incisors are designed to cutIncisors are designed to cut• Cutting edge = Cutting edge = incisal edgeincisal edge

LILI CICI CICI LILI

lili cici cici lili

IncisorsIncisors

The tongue side, or lingualThe tongue side, or lingualsurface, is shaped like a surface, is shaped like a shovel: shovel: • • aids in guiding the food intoaids in guiding the food into the mouth. the mouth. • • is the major contributor tois the major contributor to the anterior guidance of the anterior guidance of occIusionoccIusion

Canines Canines

• 4 canines total: 4 canines total: 2 maxillary, 2 mandibular2 maxillary, 2 mandibular• Designed to function as Designed to function as

holding or grasping teethholding or grasping teeth• Also used as a tearing toolAlso used as a tearing tool• Longest teeth in the human Longest teeth in the human

dentitiondentition• Canine guidance in lateral Canine guidance in lateral

excursive movements of excursive movements of occlusionocclusion

CCCC

CC CC

CaninesCanines

• Canines are the best anchored Canines are the best anchored and most stable teeth, since they and most stable teeth, since they have the longest roots.have the longest roots.

• Canines are shaped triangularly Canines are shaped triangularly in cross section. This makes it in cross section. This makes it possible for a canine to hold its possible for a canine to hold its place in the corner of the mouth.place in the corner of the mouth.

• This shape resists both anterior This shape resists both anterior and posterior forces of and posterior forces of displacement.displacement.

Premolars (or Bicuspids)Premolars (or Bicuspids)

• A cross between canines and A cross between canines and molars.molars.

• 8 premolars: 1st and 2nd in 8 premolars: 1st and 2nd in each tooth quadranteach tooth quadrant

• Not as long as canines, and Not as long as canines, and usually have two cusps, rather usually have two cusps, rather than one large ridge.than one large ridge.

• Like canines they aid in holding Like canines they aid in holding food, and they also help grind food, and they also help grind rather than incise it (the pointed rather than incise it (the pointed buccal cusps hold the food buccal cusps hold the food while the lingual cusps grind it.)while the lingual cusps grind it.)

MolarsMolars

• Larger than premolarsLarger than premolars• Most posterior teeth: 1st, 2nd and Most posterior teeth: 1st, 2nd and

3d molars3d molars• The function of the 12 molars is to The function of the 12 molars is to

chew or grind up food.chew or grind up food.• They do not have incisal edges, They do not have incisal edges,

instead they have instead they have cuspscusps, which , which are designed to interlock upper are designed to interlock upper and lower molars.and lower molars.

• There are 4 or 5 cusps on the There are 4 or 5 cusps on the occlusal surface of each molar.occlusal surface of each molar.

MolarsMolars

Maxillary (upper) andMaxillary (upper) andmandibular (lower) molarsmandibular (lower) molarsdiffer greatly from each differ greatly from each other in shape, size, numberother in shape, size, numberof cusps, and roots.of cusps, and roots.

Surfaces of TeethSurfaces of Teeth

• Crowns of the teeth are Crowns of the teeth are divided into surfaces divided into surfaces named according to the named according to the direction in which they direction in which they face.face.

• Anterior teeth have Anterior teeth have 4 surfaces (m, f, d, l) plus 4 surfaces (m, f, d, l) plus the the incisal ridge or edgeincisal ridge or edge

• Posterior teeth have Posterior teeth have 5 surfaces. The 5th 5 surfaces. The 5th surface is the surface is the occlusal occlusal surfacesurface

Surfaces of TeethSurfaces of Teeth

• Surfaces facing the Surfaces facing the tongue = tongue = lingual lingual surfacessurfaces..

• Surfaces facing the Surfaces facing the cheeks = cheeks = facial facial surfacessurfaces, or , or labial (lip) labial (lip) surfacesurface for anterior for anterior teeth, teeth, buccalbuccal (cheek) (cheek) surfacesurface for posterior for posterior teethteeth

Surfaces of TeethSurfaces of Teeth

• A tooth surface facing that of A tooth surface facing that of a neighboring tooth in the a neighboring tooth in the same arch (next to each same arch (next to each other) is called a other) is called a proximal proximal surfacesurface..

• Each tooth has two proximal Each tooth has two proximal surfaces: surfaces: mesialmesial and and distaldistal. . The The mesial proximal surfacemesial proximal surface of a tooth is closest to the of a tooth is closest to the midline of the face. The midline of the face. The distal distal proximal surfaceproximal surface faces away faces away from the midline.from the midline.

Division of SurfacesDivision of Surfaces

For the purpose of facilitating the For the purpose of facilitating the location of various areas within a location of various areas within a specific surface of a tooth, the specific surface of a tooth, the surface is divided into thirds - surface is divided into thirds - mesial, middle and distal thirdmesial, middle and distal third -- of of each the facial and lingual surface.each the facial and lingual surface.

Division of SurfacesDivision of Surfaces• The proximal (mesial and distal) The proximal (mesial and distal)

surfaces of a tooth are divided surfaces of a tooth are divided into a facial, a middle, and a into a facial, a middle, and a lingual third.lingual third.

• Surfaces are further divided into Surfaces are further divided into sections perpendicular to the sections perpendicular to the above, i.e. any of the proximal, above, i.e. any of the proximal, facial, or lingual surfaces are facial, or lingual surfaces are divided into an incisal, a middle, divided into an incisal, a middle, and a cervical third.and a cervical third.

• Posteriorly, the incisal 1/3 Posteriorly, the incisal 1/3 is called the occlusal 1/3.is called the occlusal 1/3.

Line AnglesLine Angles

The The line angleline angle forms the junction forms the junctionbetween two tooth surfaces; e.g.,between two tooth surfaces; e.g.,the junction of the buccal surfacethe junction of the buccal surfaceand the occlusal (incisal) surface and the occlusal (incisal) surface of a tooth is a of a tooth is a line angleline angle..

• Line Angles for Anterior TeethLine Angles for Anterior Teeth

Line AnglesLine Angles

• Line Angles for Posterior TeethLine Angles for Posterior Teeth

Line AnglesLine Angles

Point AnglesPoint Angles

A A point anglepoint angle is the is the point at which three point at which three surfaces meet; e.g. the surfaces meet; e.g. the point at which the point at which the mesial, labial and mesial, labial and incisal surfaces join is incisal surfaces join is called the mesio-labio-called the mesio-labio-incisal point angleincisal point angle

Point AnglesPoint Angles

• Point Angles for Anterior TeethPoint Angles for Anterior Teeth

Point AnglesPoint Angles

• Point Angles for Posterior TeethPoint Angles for Posterior Teeth

LandmarksLandmarks

• The crown portion of teeth The crown portion of teeth develops from 4 or more develops from 4 or more growth centers or growth centers or lobeslobes..

• The lobes grow and The lobes grow and eventually fuse leaving but a eventually fuse leaving but a line or groove on the erupted line or groove on the erupted tooth where fusion of the tooth where fusion of the lobes took place.lobes took place.

• These shallow grooves or These shallow grooves or lines that separate the original lines that separate the original growth centers are called growth centers are called developmental groovesdevelopmental grooves..

LandmarksLandmarks

• Incisors, canines and most Incisors, canines and most premolars are developed premolars are developed from 4 lobes, 3 facial and from 4 lobes, 3 facial and 1 lingual.1 lingual.

• 1st molars are developed 1st molars are developed from 5 lobes: the upper from 5 lobes: the upper from 2 facial and 3 lingual, from 2 facial and 3 lingual, the lower from 2 lingual the lower from 2 lingual and 3 facial lobes.and 3 facial lobes.

• 2nd molars are developed 2nd molars are developed from 4 lobes, 2 facial and 2 from 4 lobes, 2 facial and 2 lingual.lingual.

LandmarksLandmarks• Anterior teeth show 2 develop-Anterior teeth show 2 develop-

mental grooves on their labial mental grooves on their labial surfaces. These 2 grooves surfaces. These 2 grooves separate the 3 lobes that formed separate the 3 lobes that formed the labial surface.the labial surface.

• The fourth developmental lobe The fourth developmental lobe of anterior teeth is located at the of anterior teeth is located at the lingual surface of the crown.lingual surface of the crown.

• This fourth lobe is called the This fourth lobe is called the cingulum, and it makes up the cingulum, and it makes up the bulk of the cervical third of the bulk of the cervical third of the lingual surface of an anterior lingual surface of an anterior tooth.tooth.

LandmarksLandmarks

• A A concavityconcavity is a carved-out is a carved-out section or area -> Fossasection or area -> Fossa

• The opposite of a concavityThe opposite of a concavityis a is a convexityconvexity, a bulging out , a bulging out area of the tooth crownarea of the tooth crown- > Ridge, Cusp - > Ridge, Cusp

(no cusp on incisors!)(no cusp on incisors!)

LandmarksLandmarks

• A A fossafossa (plural fossae) is a (plural fossae) is a depression or concavity, on an depression or concavity, on an area of the tooth crown.area of the tooth crown.

• A A tubercletubercle is a small elevation of is a small elevation of enamel on some portion of the enamel on some portion of the crown of a tooth.crown of a tooth.

FossaeFossae

LandmarksLandmarks

• Anterior teeth have a lingual Anterior teeth have a lingual fossa between the fossa between the marginal marginal ridgesridges and incisal to the and incisal to the cingulumcingulum..

• A pinpoint hole within the A pinpoint hole within the fossa, is called a fossa, is called a pitpit..

• Pits are named after their Pits are named after their location on a tooth; e.g. location on a tooth; e.g. a a lingual pitlingual pit occurs on the occurs on the lingual surface of a tooth.lingual surface of a tooth.

CC

LandmarksLandmarks

• A A cuspcusp is a mound on the is a mound on the crown portion of the tooth crown portion of the tooth that makes up a major that makes up a major division of its occlusal or division of its occlusal or incisal surface.incisal surface.

• Cusps are found on Cusps are found on premolars, molars and premolars, molars and canines, not on incisors.canines, not on incisors.

• Cusp are name after their Cusp are name after their location (MB, DB, ML, DL)location (MB, DB, ML, DL)

CCCC

CC CC

Buccal

Lingual

Distal Mesial

Mesio-BuccalMesio-Buccal

Mesio-LingualMesio-Lingual

Disto-BuccalDisto-Buccal

Disto-LingualDisto-Lingual

LandmarksLandmarks

• Marginal ridgesMarginal ridges are the are the rounded borders of rounded borders of enamel that form the enamel that form the mesial and distal mesial and distal shoulders of the occlusal shoulders of the occlusal surfaces of posterior teeth surfaces of posterior teeth and the mesial and distal and the mesial and distal shoulders of the lingual shoulders of the lingual surface of the anterior surface of the anterior teeth.teeth.

LandmarksLandmarks

Triangular ridgesTriangular ridges (TR) (TR)are the main ridges are the main ridges on each cusp that run on each cusp that run from the cusp tip to from the cusp tip to the central part of thethe central part of theocclusal surface, i.e. occlusal surface, i.e. the the central, mesial,central, mesial,distal grooves and distal grooves and pitspits

MR = Marginal ridgeMR = Marginal ridge

TRTR TRTR

TRTRTRTR

MRMRMRMR

LandmarksLandmarks

A A transverse ridgetransverse ridge is is the union of a buccal the union of a buccal and a lingual triangular and a lingual triangular ridge that cross the ridge that cross the occlusal surface of a occlusal surface of a posterior tooth.posterior tooth.