Figure 1.34 Enamel, dentin, and pulp exposed in an acutely fractured canine tooth.
Figure 1.35 Canine tooth and surrounding structures.
1.20 Tooth Eruption
The maxillary teeth generally erupt before their mandibular counterparts. Eruption of the incisors precedes that of the canines. The premolars and molars erupt last.
There are normally 26 deciduous teeth. Between 11 and 15 days, the incisors erupt; at 17–19 days, the canines erupt; between 24 and 30 days, all premolars erupt. The secondary (adult) upper first molars erupt later, between 37 and 60 days. At 60 days, the deciduous dentition is complete. By seven months, the permanent teeth should be fully erupted (Table 1.1).
Table 1.1 Approximate age by which permanent teeth erupt (in days).
| Upper | Lower | |
|---|---|---|
| Incisors | ||
| Central | 103 | 113 |
| Middle | 114 | 119 |
| Lateral | 135 | 132 |
| Canine | 153 | 149 |
| Premolar | ||
| Second | 150 | |
| Third | 168 | 173 |
| Fourth | 151 | 174 |
| Molar | 162 | 130 |
Figure 1.36 Directions in the oral cavity.
Figure 1.37 Right maxillary and mandibular apical and coronal directions.
Illustration 1.2 Tooth anatomy and direction nomenclature.
Surfaces of Teeth and Directions in the Mouth
Vestibular/Buccal/Labial
Vestibular is the correct term referring to the surface of the tooth facing the vestibule or lips; buccal and labial are acceptable alternatives. The term “facial” specifically refers to the surfaces of the rostral teeth visible from the front. According to Dr. A.J. Bezuidenhout, a veterinary anatomist at Cornell University, “facial” is a bit of a misnomer. Traditionally “facial” has been used in human dentistry for the aspect of teeth visible from the front, i.e. incisors and canines.
Lingual/Palatal
Lingual: The surface of a mandibular or maxillary tooth facing the tongue is the lingual surface. Palatal can also be used when referring to the lingual surface of maxillary teeth.
Mesial/Distal
Mesial and distal are terms applicable to tooth surfaces. The mesial surface of the first incisor is next to the median plane; on other teeth it is directed toward the first incisor. The distal surface is opposite from the mesial surface.
Rostral/Caudal
Rostral and caudal are the positional and directional anatomical terms applicable to the head in a sagittal plane in non‐human vertebrates. Rostral refers to a structure closer to, or a direction toward, the most forward structure of the head. Caudal refers to a structure closer to, or a direction toward, the tail (Figures 1.36 and 1.37) (Illustration 1.2).
Further Reading
1 American Veterinary Dental College (n.d.). Veterinary dental nomenclature. https://avdc.org/avdc‐nomenclature/ (accessed 27 August 2021).
2 Anderson, K.V. and Pearl, G. (1974). Transmedian innervation of canine tooth pulp in cats. Exp. Neurol. 44: 35–40.
3 Arredondo, J., Agut, A., Rodríguez, M.J. et al. (2013). Anatomy of the temporomandibular joint in the cat: a study by microdissection, cryosection and vascular injection. J. Feline Med. Surg. 15: 111–116.
4 Arzi, B. and Staszyk, C. (2019). The temporomandibular joint through the lens of comparative anatomy. In: Contemporary Management of Temporomandibular Disorders (eds. S.T. Connelly, G.M. Tartaglia and R.G. Silva), 41–50. Cham: Springer.
5 Barton‐Lamb, A.L., Martin‐Flores, M., Scrivani, P.V. et al. (2013). Evaluation of maxillary arterial blood flow in anesthetized cats with the mouth closed and open. Vet. J. 196: 325–331.
6 Berman, E. (1974). The time and pattern of eruption of the permanent teeth of the cat. Lab. Anim. Sci. 24 (6): 929–931.
7 Bishop, M.A. and Malhotra, M. (1990). An investigation of lymphatic vessels in the feline dental pulp. Am. J. Anat. 187: 247–253.
8 Buckland‐Wright (1975). Structure and function of cat skull bones in relation to the transmission of biting forces. PhD thesis. University of London.
9 Byers, M.R. and Matthews, B. (1981). Autoradiographic demonstration of ipsilateral and contralateral sensory nerve endings in cat dentin, pulp, and periodontium. Anat. Rec. 201 (2): 249–260.
10 Crossley,