The Proper Dental Nomenclature

Francioli Daniele*
Department of Orthodontics, University of Siena, Italy

*Corresponding author: Francioli Daniele, Department of Orthodontics, University of Siena, Italy

Published: 17 May, 2018
Cite this article as: Daniele F. The Proper Dental Nomenclature. J Dent Oral Biol. 2018; 3(4): 1134.


The dental numeration begins with the deciduous dentition, based on the birth of the teeth; this is why a new dental nomenclature system has been created. The intuitive numerical simplicity leads to easy learning by dental practitioners. The national and international scientific literature focused the mistake that has been made in the past for the numeration of dental elements. The purpose of this work is to establish a proper dental nomenclature system.


After many years, I finally decided to write this article about the possible mistake made in dental nomenclature.
Man has a heterodont set of teeth, that is to say he has different forms and dimension of teeth as a consequence of his omnivorous alimentation: cutting teeth (incisors), sharped teeth (canines) are respectively designated to cut and to obtain food laceration, multiplecuspid teeth (molars and premolars) permit to mince it. Man has a diphyodont dentition, characterized by two different dentitions during his life: deciduous dentition (primary or calf teeth) and permanent dentition (secondary or definitive). Between six and twenty-four months of a baby life, twenty teeth progressively appear: eight incisors, four canines and eight molars. Around six years of age the growth of thirty-two permanent teeth begins. Dentists have to use a common language that permits a precise teeth’s identification. The necessity to adopt a teeth’s numeration system would be intuitive: in this way, it avoids a lot of mistakes. For this reason, the World Health Organization (WHO) established a teeth’s numeration system in order to associate each information to a specific tooth in an univocal way. But it still remains other in-use classifications: one is especially used in the United-States, consecutive numbering system A.D.A., the other one in military field, Palmer notation method. For an easier identification of a tooth in the oral cavity, whether the upper teeth or the lowers, they are divided by an imaginary line, called median line, in two hemiarchs, the right’s and the left’s ones. Mouth is so divided into four quarters:

Right superior’s quarter Left superior’s quarter
Right inferior’s quarter Left inferior’s quarter

Therefore this schema - as all the international numeration’s systems - represents the patient seen in a frontal view, where right and left positions refer to the patient and never to the doctor. In the dental field, as mentioned before, several numeration systems are employed: the most used one is: The International Standards Organization Designation System (ISO System) » defined by the FDI-WHO: it deals with a system that uses a double number code. The first one indicates the quarter and the second one is related to the tooth position, starting to enumerate from the face’s median line level. As to permanent teeth, at present the numeration begins from the right superior central incisor, to which number 1 is attributed. The second quarter is represented by the left maxillary characterized by number 2, followed by numbers from 1 to 8 (Figure 1). The third quarter involves the left mandibular area and the count begins, in this case too, from the median line continuing in distal zone. Finally, the numeration of the right mandible quarter is marked by the number 4, followed by numbers from 1 to 8.
For the deciduous elements, the numeration uses the same criterion; for the right superior quarter number five is assigned; six, seven and eight, on the contrary, indicate respectively the left superior quarter, the left inferior one and the right inferior one. The deciduous teeth’s numbers begin from one to five.
Here is my opinion; we can understand the numeration system mistake made in 1970 by the WHO, because, if the calf teeth represent the primary dentition, logically the numeration should begin from the number 1 and the quarters should be 1, 2, 3 and 4. So, we could begin to count teeth from the first deciduous tooth erupted in the arch, conventionally the inferior central incisor, that is to say the 11th left. Moving on we proceed clockwise as seen in the scheme (anti-clockwise in the patient mouth) to the 21st right central incisor, the 31st right superior central incisor and finally the 41st left superior incisor, in order to continue the erupted teeth numeration as showed in the scheme. Subsequently the permanent teeth: the quarters’ numeration should begin from 5, 6, 7 and 8. So, we use the 5th quarter in the left inferior hemiarch, the 6th in the right inferior one, the 7th in the right superior one and finally the 8th in the left superior one.
To conclude I state that the numeration system for deciduous teeth concern numbers counted from 1 to 5, therefore skipping the numbers 6 to 8: thereby we should count teeth from 11 to 15, from 21 to 25, from 31 to 35 and from 41 to 45. For the secondary dentition, we count permanent teeth from 1 to 8, so we should count teeth from 51 to 58, from 61 to 68, from 71 to 78 and from 81 to 88. This type of numeration appears much more simple and intuitive, as it reflects the sequence of dental eruption, while the other one used nowadays seems less accurate.
This corrected nomenclature is called: “Francioli nomenclature”.

Figure 1

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Figure 1
Nomenclature Francioli.