This is a list ofdefinitions of commonly used terms of location and direction in dentistry. This set of terms provides orientation within the oral cavity, much asanatomical terms of location provide orientation throughout the body.
The direction toward the front of the head or the lips, as opposed toposterior, which refers to the directions toward the back of an individual's head. The termanterior teeth refers toincisors andcanines, as opposed to premolars and molars, which areposterior teeth.[1]
Apical
The direction toward the root tip(s) or apex(es) of a tooth (the apices), as opposed tocoronal, which refers to the direction toward the crown. It may also refer to something relating to the roots, such asapical support. When referring to direction in relation to entities on or of the crown, this term can be synonymous with bothcervical andgingival.[1]
Approximal
Surfaces which form points of contact between adjacent teeth.[2]
Axial
Aplane parallel to the surface of a tooth. For example, if a drill bur would be inserted into a tooth from any side (proximal,vestibular,oral), the depth of the hole is defined from the axial wall of the hole (from the long axis walls (vertical surfaces bounding the tooth)).[1]
Buccal
The side of a tooth that is adjacent to (or the direction toward) the inside of thecheek, as opposed tolingual orpalatal (bothoral), which refer to the side of a tooth adjacent to (or the direction toward) thetongue orpalate, respectively. Although technically referring only to posterior teeth (where the cheeks are present instead of lips, use of this term has incorrectly extended to all teeth, anterior and posterior), this term has inaccurately been employed to describe thevestibular surface of (or directions in relation to) anterior teeth as well.[1]
Cervical
Meansneck inLatin (as incervical vertebrae), and refers to the narrowing of the contours of the tooth surface at or near theCEJ, where the crown meets the root. When referring to direction in relation to entities on or of the crown, it is nearly synonymous with bothapical andgingival.[1]
Coronal
The direction toward the crown of a tooth, as opposed toapical, which refers to the direction toward the tip(s) of the root(s) or apex(es). It may also refer to something relating to the crown, such ascoronal forces.[1]
ThisX-ray film depicts some of the teeth in the lower right quadrant. The arrows point in the following directions:distal ←,mesial →,coronal ↑,apical ↓.
Distal
The direction toward the gingiva beyond the tooth furthest from theanterior midline (the 'mostposterior tooth' or last tooth) in eachquadrant of adental arch, as opposed tomesial, which refers to the direction toward the anteriormidline. Each tooth can be described as having a distal surface and, forposterior teeth, adistobuccal (DB) and adistolingual (DL) corner orcusp.[1]
Facial
The side of a tooth that is adjacent to (or the direction toward) the inside of thelips, as opposed tolingual orpalatal (bothoral), which refer to the side of a tooth adjacent to (or the direction toward) thetongue orpalate, respectively, of the oral cavity. However, this term has been incorrectly used for bothbuccal andlabial, being also applied to the side of a tooth that is adjacent to (or the direction toward) the inside of thecheek (instead of the more accurate term,vestibular).[1][3][4]
Gingival
The direction toward thegingiva (gums), synonymous withcervical and similar to apical. However, locations on teeth already moreapical to the interface of the crown and root, referred to as theCEJ, tend not to be described using this term, as it would lead to confusion, as the exact definition is ambiguous. Additionally, this term would not be used when referring to a toothex vivo.[1]
Incisal
The direction toward the biting edge ofanterior teeth or something relating to this edge, such as the termsincisal guidance orincisal edge. This is the sister term toocclusal, which related to the analogous location onposterior teeth.[1]
Inferior
The direction toward the feet of a human's body, as opposed tosuperior, which refers to the direction toward the head. However, use of these terms should enjoy only limited usage when discussing features of a tooth, as, for example, something more inferior on amandibular tooth will be situated more superior on amaxillary tooth, as they exhibit an inverted relationship. It is for this reason that the termscoronal andapical are substituted.[1]
Interproximal
An adjective meaning between teeth. For example,interproximal teeth refers to the space between adjacent teeth.[1][5]
Labial
The side of a tooth that is adjacent to (or the direction toward) the inside of thelip (labium), as opposed tolingual orpalatal (bothoral), which refer to the side of a tooth adjacent to (or the direction toward) thetongue orpalate, respectively, of the oral cavity. Although technically referring only to anterior teeth (where the lips (labia) are present instead of cheeks), use of the termlabial has inaccurately extended to all teeth, anterior and posterior (instead ofvestibular).[1][5]
Lateral
A tooth which is away from the midline, such as lateral incisor,[1] or the sides of a tooth.[6]
Lingual
The side of a tooth adjacent to (or the direction toward) the tongue (lingua, compare linguistics and language), as opposed tobuccal,labial, orvestibular which refer to the side of a tooth adjacent to (or the direction toward) the inside of the cheek or lips, respectively. Although this term is technically specific to themandible, it enjoys extensive use in reference to themaxilla as well (seePalatal).[1][5]
A number of different 'margins' are involved in dentistry. The edge of tooth structure that is prepared to meet the edge of a prostheticcrown is called a margin, as is the aforementioned edge of the crown; an example of this usage would be "a poorly fitting crown might exhibitmarginal leakage." Thegingiva andbone that abut the teeth are referred to as 'marginal', as inmarginalperiodontitis. The bulk of tooth structure on theocclusal surface at the point of contact of posterior teeth is referred to as themarginal ridge.[1]
The direction toward the anteriormidline in a dental arch, as opposed todistal, which refers to the direction toward the gingiva beyond the tooth furthest from theanterior midline (the 'mostposterior tooth' or last tooth) in each quadrant. Each tooth can be described as having a mesial surface and, forposterior teeth, amesiobuccal (MB) and amesiolingual (ML) corner orcusp.[1]
An occlusal view of acomplete maxillary denture. The green line, indicating thedental midline, is the defining line when it comes to mesial-distal direction. The blue arrow, which indicates a mesial direction, applies to the opposite side as well up until the green line. The red arrow is directly buccal to the right first maxillary molar, and the name label for the patient (Martin) is embedded in theresin directly palatal to the same tooth.
Midline
Main article:Dental midline. Roughly, an imaginary vertical line dividing the left and right sides of the mouth at the teeth.
The direction toward the biting surface ofposterior teeth or something relating to this surface, such as the termsocclusal interference orocclusal surface. This is the sister term toincisal, which related to the analogous location onanterior teeth.[1][5]
Oral
The side of a tooth adjacent to (or the direction toward) the oral cavity, as opposed tobuccal,labial orvestibular, which refer to the side of a tooth adjacent to (or the direction toward) the inside of the cheek, lips or vestibule respectively.Oral includes bothpalatal andlingual. Alternatively,lingual has been used as a blanket term instead although this specifically refers only to the side of a tooth that is adjacent to (or the direction toward) thetongue, technically specific to themandible.[1][5]
Palatal
The side of a tooth adjacent to (or the direction toward) thepalate, as opposed tobuccal,labial orvestibular which refer to the side of a tooth adjacent to (or the direction toward) the inside of the cheek, lips and vestibule of the mouth respectively. This term is strictly used in themaxilla.[1]
Posterior
The direction toward the back of an individual's head, as opposed toanterior, which refers to the directions toward an individual's lips. The termposterior teeth refers topremolars andmolars, as opposed toincisors andcanines, which areanterior teeth.[1][5]
Proximal
The surfaces of teeth that normally lie adjacent to another tooth. Proximal includes bothmesial anddistal, such as when referring to theproximal surfaces of teeth.[1]
Quadrant
Dental quadrants The dentition is divided into four quarters. The twodental arches form anoval, which is divided intoquadrants which are numbered from 1 to 4:[7]
Upper right quadrant: upper right first incisor to upper right wisdom tooth
Upper left quadrant: upper left first incisor to upper left wisdom tooth
Lower right quadrant: lower right first incisor to lower right wisdom tooth
Lower left quadrant: lower left first incisor to lower left wisdom tooth
Sextant
One of six groups of adjacent teeth, excluding the wisdom teeth. The front sextants go from canine to canine, and there are sextants on the right and left of these. SeePeriodontal examination.
Superior
The direction toward the head of a human's body, as opposed toinferior, which refers to the direction toward the feet. However, use of these terms should enjoy only limited use when discussing features of a tooth, as, for example, something more superior on amandibular tooth will be situated more inferior on amaxillary tooth, as they exhibit an inverted relationship. It is for this reason that the termscoronal andapical are substituted.[1]
Vestibular
The side of a tooth that is adjacent to (or the direction toward) the inside of thecheeks andlips, as opposed tolingual orpalatal (bothoral), which refer to the side of a tooth adjacent to (or the direction toward) thetongue orpalate, respectively, of the oral cavity. Vestibular includes bothbuccal andlabial.[3][4] Alternatively, the term facial has been used instead although this specifically refers only to the side of a tooth that is adjacent to (or the direction toward) the inside of thelips, as opposed tolingual orpalatal (bothoral), and not thecheeks.[1]
This photo shows teeth #2-5 (Universal numbering system). Tooth #3, the upper right firstmolar, has an MO (mesial-occlusal)goldinlay. This molar is both posterior, as well as distal, to thepremolars in front of it.
Most of the principal terms can be combined using their correspondingcombining forms (such asmesio- formesial anddisto- fordistal). They provide names for directions (vectors) and axes; for example, the coronoapical axis is the long axis of a tooth. Such combining yields terms such as those in the following list. The abbreviations should be used only in restricted contexts, where they are explicitly defined and help avoid extensive repetition (for example, a journal article that uses the term "mesiodistal" dozens of times might use the abbreviation "MD"). The abbreviations are ambiguous: (1) they are not specific to these terms; (2) they are not even one-to-one specific within this list; and (3) some of the combined terms are little used, and the abbreviations of the latter are even less used. Therefore, spelling out is best.
^abWorld Association of Veterinary Anatomists, International Committee on Veterinary Gross Anatomical Nomenclature, World Association of Veterinary Anatomists, International Committee on Veterinary Histological Nomenclature, World Association of Veterinary Anatomists and International Committee on Veterinary Embryological Nomenclature (1994) Nomina Anatomica Veterinaria: Fourth Edition. Zurich and Ithaca: World Association of Veterinary Anatomists
