Dental Landmarks: Tooth Anatomy PDF

ANATOMIC LANDMARK OF TOOTH SURFACE Landmarks mean Elevations, depressions and grooves are present on the surfaces of teeth, and different terminologies are used to describe these landmarks. To study an individual tooth intelligently, we must be able to recognize all landmarks of importance by nam...

ANATOMIC LANDMARK OF TOOTH SURFACE Landmarks mean Elevations, depressions and grooves are present on the surfaces of teeth, and different terminologies are used to describe these landmarks. To study an individual tooth intelligently, we must be able to recognize all landmarks of importance by name. These include Concave: A curvature that leans inward Convex: A curvature that extends outward. Opposite of concave Concave: A curvature that leans inward Convex: A curvature that extends outward. Opposite of concave Concave: A curvature that leans inward Convex: A curvature that extends outward. Opposite of concave CONVEX CONCAVE CONVEX CONCAVE Lobe: Developmental lobe is the growth center in the development of the crown of the tooth. Each tooth begins to develop from four or more growth centers These centers are known as developmental lobes then unite together to form the crown of the tooth. Mature form of the lobes are : cusps, mamelon and cingulum. Lobe: Developmental lobe is the growth center in the development of the crown of the tooth. Cusps ,mamelons and cingulum are representative ( MATURE ) of lobes. Anterior teeth form from 4 lobes ( 3 FACIAL , 1 PALATAL OR LINGUAL ) Posterior teeth :PREMOLAR form from 3 FACIAL LOBE and 1 LINGUAL LOBE per LINGUAL CUSP MOLAR FORM FROM 1 LOBE PER MAJOR CUSP A cusp is an elevation or mound on the crown portion of a tooth making up a divisional part of the occlusal surface Definition: Cusp is an elevation of various size and shape. Origin: Cusp denote a mature form of lobe Site:. located on the occlusal surface of posterior teeth and incisal third of canine. Shape: Cusp is pyramidal structure with four sides formed by four ridges that run down from the cusp tip Structure: Cusp is composed of enamel,dentin and have a pulp horn. Shape: Cusp is pyramidal structure with four sides formed by four ridges that run down from the cusp tip MESIAL AND DISTAL CUSP RIDGES ( CUSP SLOPE ) BUCCAL / LINGUAL CUSP RIDGES TRIANGULAR RIDGE OF THE CUSP CUSP TIP BUCCAL RIDGE DISTOBUCCAL CUSP MESIOBUCCAL RIDGE CUSP RIDGE TRIANGULAR RIDGE  Classification of teeth according to cusp number: One cusp (termed Cuspid 1 tooth): Canine. Two cusps (termed Bicuspid tooth): premolars except mandibular second premolar 1 Three cusps: mandibular 1 second premolar and may be maxillary third molar. 2 3 2  Classification of teeth according to cusp number: Four cusps: maxillary molars, 1 2 mandibular permanent second and third 4 molars, and mandibular 3 deciduous first molar. 1 2 Five cusps: mandibular permanent first molar, 4 mandibular deciduous 3 5 second molar When naming cusps, the proximal surface is stated first, then the other axial surface. B BUCCAL BUCCAL D M PALATAL PALATAL P When naming cusps, the proximal surface is stated first, then the other axial surface. B DISTO-BUCCAL MESIO-BUCCAL D M MESIO-PALATAL DISTO-PALATAL P A ridge : are any linear, flat elevations on the surface of a tooth , and they are named according to their location or form. Types of Ridges according to location: 1.Labial ridge: It is a ridge extend vertically from cervical ridge to cusp tip of canine Site: Labial surface of canine. LABIAL RIDGE Types of Ridges according to location: 2. Lingual ridge: It is a ridge extend vertically from cingulum to cusp tip of canine. Site: Lingual surface of canine. Types of Ridges according to location: 3. Cervical ridge: It is a ridge running mesiodistally on the cervical one-third of the buccal surface of the crown, found on all deciduous teeth but only on the permanent molars More elevated in deciduous teeth Types of Ridges according to location: 4. Buccal ridge: It is a ridge extend vertically from cervical ridge to cusp tip of premolars. Site: Buccal surface of premolars. Types of Ridges according to location: 5- PROXIMAL Marginal ridges: Are the rounded borders of the enamel LOCATION: 1-The mesial and distal margins of the occlusal surfaces of POSTERIOR 2-The mesial and distal margins of the lingual surfaces of ANTERIOR PROXIMAL MARGINAL RIDGE Types of Ridges according to location: 6. Incisal ridge: It is a ridge found at the incisal margin of anterior teeth. by time and attrition it become incisal edge.. Types of Ridges according to location: 7. Cusp ridge: It is a ridge extend from cusp tip and descends in directions other than toward the central part ( MESIAL AND DISTAL ) of the occlusal surface The cusp resembles 4- sided pyramid Types of Ridges according to shape: 1. Triangular ridge: A ridge that slopes downward from a cusp tip of posterior teeth toward the center of the occlusal surface , narrow at its tip and broader at its base. lt named triangular ridge because the slope of each side of the ridge are inclined to resemble a two sides of triangle. Also, it is named occlusal ridge Types of Ridges according to shape: 1. Triangular ridge: Every cusp has 4 Ridges but only one is a triangular ridge The cusp resembles 4- sided pyramid Types of Ridges according to shape: 2-Transverse ridges: It is the union of two triangular ridges crossing transversely the surface of a posterior tooth  B Types of Ridges according to shape: 3- Oblique ridges: It is a ridge crossing obliquely the occlusal surfaces of maxillary molars. It is formed by the union of D M the triangular ridge of the distobuccal cusp and the distal cusp ridge of the mesiolingual cusp. P A tubercle: is a smaller elevation on some portion of the crown produced by an extra formation of enamel DEVIATIONS from the normal form, the cusp of Carabelli is a tubercle SITE: The cusp of Carabelli is a fifth cusp (NOT TRUE CUSP ) present on the palatal surface of the maxillary first molars. NB. The tubercle is composed of enamel only. A CINGULUM : Large rounded elevation on the cervical third of lingual surface of anterior teeth. Its convexity mesiodistally resembles a girdle encircling the lingual surface at the cervical third A CINGULUM : Large rounded elevation on the cervical third of lingual surface of anterior teeth. SITE : PERMANENT ANTERIOR TEETH A Mamelon: is any one of three small rounded elevations located on the incisal ridge of newly erupted permanent incisors only. By time due to friction of eating: Attrition occurred to mamelons and become incisal ridge. Groove: linear depression 1. Developmental Groove: Linear depressions (slight depression) dividing the lobes on an anterior tooth, and running parallel with the long axis ALSO used to describe the dissectional grooves or Linear depressions found on occlusal surface of posterior teeth and may extend labially, buccally, lingually or mesially. Origin : Line of fusion of primary lobes Types: Central developmental groove on the occlusal surface of teeth. Buccal developmental groove: Comes from occlusal to the buccal surface. Lingual developmental groove: Comes from occlusal to lingual surface. Types: LABIAL developmental groove : Comes from incisal to labial surface. Mesial developmental groove: Comes from occlusal to mesial surface of maxillary first premolar 2. Supplemental Groove: is a shallow linear depression on the occlusal surface branched from the developmental groove and does not mark the junction of primary parts. 3. Fissure: is a deep linear cleft on the occlusal or buccal surfaces found in the bottom of the developmental groove. Origin: Fissure result from incomplete union of enamel between lobes. 3. Fissure: is a deep linear cleft on the occlusal or buccal surfaces found in the bottom of the developmental groove. Fissure is the most common site for development of dental caries 4. Fossa: is a round or triangular shallow depression or CONCAVITY Named according to its location or shape Types A- Central fossa : Union between three or four lobes Types B- Triangular fossa: On the occlusal surface of all posterior teeth beside Mesial & Distal marginal ridges. Types C-Lingual fossa: On the lingual surface of anterior teeth. Lingual fossa of canine is divided into two lingual fossae by lingual ridge The depression on the lingual surface of an anterior tooth bordered by the incisal edge, the cingulum and the marginal ridges. 5. Pits: are small pinpoint depressions located at the junction of developmental grooves or at terminals of those grooves AND found in the bottom of fossa Origin: pits result from incomplete union of enamel between lobes. CENTRAL PIT : is a term used to describe a landmark in the central fossa of molars where developmental grooves join Site A.Occlusal surface of posterior teeth. B. Lingual surface of anterior teeth commonly in maxillary permanent lateral incisor. C. Buccal and lingual surface at the end of buccal and lingual developmental groove ( termed faulty pit). BUCCAL PIT IS PRESENT ONLY IN MULTIROOTED TEETH. IT IS THE UNDIVIDED PART OF THE ROOT NEAR THE CERVICAL LINE IS THE PLACE ON MULTIROOTED TEETH WHERE THE ROOT TRUNK IS DIVIDES INTO SEPARATE ROOT MANDIBULAR MOLARS AND MAXILLARY 1ST PREMOLAR ARE BIFURCATED WHILE THE MAXILLARY MOLARS ARE TRIFURCATED