ContentsSurfaces of teeth. 1Line angles and point angles. 2Depressions and Elevations on teeth. 3Division in thirds. 4ObjectivesThe prime objective of this lecture is to introduce thedental terminology and its application
Learning nomenclature is the first and very important step in understanding dental anatomy. Crown is covered with enamel and root is covered with cementum. The crown and root join at the cemento- enamel junction (CEJ) which is also called the cervical line. The junction of cementum and dentine is called cemento-dentinal junction. The junction of dentine and enamel is called dentinoenamel junction (DEJ). To study and facilitate communication various surfaces of teeth are recognized and given names.
Surfaces of teeth.Crowns of all teeth have five surfacesFacial Surface. 1.Facial surface can be labial surface or buccal surfacea. Labial surface. The surfaces of incisors and canines that.are towards the lipb. Buccal surface. The surfaces of premolars and molars.that face the cheek
(Lingual Surface (Palatal surface. 2.All surfaces facing towards the tongue palatal
Proximal Surfaces. 3a. Mesial Surface.All surfaces towards the midlineb. Distal SurfaceAll surfaces away from the midline. Mesial surface and.Distal surface are collectively called proximal surface Proximal surfaces
Incisal or Occlusal surface. 4a. Incisal surface. The surface of incisors and canines thatcome in contact with those in the opposite jaws duringthe act of closure are called incisal surfacesb. Occlusal surface. The surface of premolars and molarsthat come in contact with those in the opposite jaws.during the act of closure are called occlusal surfaces
Point angles of anterior teeth1. Mesiolabioincisal2. Distolabioincisal3. Mesiolinguoincisal4. Distolinguoincisal Point angles of Anterior teeth
Point angles of posterior teeth1. Mesiobucco-occlusal2. Distobucco-occlusal3. Mesiolinguo-occlusal4. Distolinguo-occlusal Point angles of Posterior teeth
Depressions on tooth surfacePit. A sharp pinpoint depression on the surface of the. 1enamelFossa. An irregular depression or concavity on the. 2.surface of a tooth 2 Pit. 1 1 Fossa. 2
.Sulcus. A long depression on the surface of a tooth. 34. Groove is a shallow linear depression on the surfaceof a tooth.A developmental groove is a shallow groove or linebetween the primary parts of the crown or root.A supplemental groove is less distinct and does notmark the junction of primary parts.
Elevations on tooth surface.Cusp. An elevation or mound on the crown of a tooth. 1 C C C C C C Cusps
2. Cingulum is the lingual lobe of an anterior tooth andmakes up the bulk of the cervical third of the lingual surface. C Cingulum
3. Lobe is one of the primary sections of formation in thedevelopment of the crown. Cusps and mamelons arerepresentative of lobes.4. Mamelons are three rounded protuberances found on theincisal ridges of newly erupted incisor teeth.
Ridge. A linear elevation on the surface of a toothMarginal ridges are rounded borders of enamel that formthe mesial and distal margins of the occlusal surfaces ofposterior teeth and the mesial and distal margins of thelingual surfaces of anterior teeth.Triangular ridge is a ridge that descends from the tips of thecusps of molars and premolars towards the centre part ofthe occlusal surface.Transverse ridge is formed by the union of buccal and.lingual triangular ridgesOblique ridge is a ridge obliquely crossing the occlusalsurfaces of maxillary molars. Dr.Syed Sadatullah Ibnsina National Medical College
Other important termsMid line. An imaginary line dividing the upper and lower.arches into two equal halvesAnterior. Pertaining to or towards the front plane of the.bodyPosterior. Pertaining to or towards the back plane of the.body.Superior. Situated above another or towards the head.Inferior. Situated beneath another or towards the feet
Division in thirdsTo make study and communication easier the crown and.root are divided into three halves)Division in thirds occluso-gingivally (Crown cervicalCervical third. 1 MiddleMiddle third. 2Incisal/Occlusal third. 3 incisal Occlusal Middle cervical
)Division in thirds facio-lingually (CrownCrown when viewed from frontMesial third. 1Middle third. 2Distal third. 3 Distal Mesial Middle