Changes in the Dentition of Small Dogs up to 4 Months of Age

Abstract

It is common practice in EU member states to permit the entry of dogs vaccinated against rabies at the age of at least 3 months. In the absence of easily applicable comparative data, subjective disputes emerge around age. The aim of our study was to observe the development of dog teeth. During birth, an abnormally lying Yorkshire Terrier fetus was stuck in the birth canal, which led to a caesarean section, hence, the exact date of birth was known. For the next 4 months, two puppies were examined weekly, and they showed the same development. The dogs were born without teeth. At the age of 4.5 weeks, the canines I appeared, together with the adjacent incisors (i3), and the second incisor (i2) also erupted at the age of 6 weeks. A week later, a first incisor (i1) also appeared. From the age of 2.5 months, the distance between the teeth was increasing, especially on the upper dental arch. At 3.5 months of age, only the bottom front incisors (i1) had not grown in a row, and the significant distance between the top incisors, comparable to the width of the tooth, was striking. Since only two dogs of one breed were involved in this case study, the observations cannot be generalized.

Morphometrical and Immunohistochemical Evaluation of Kidney as an Indirect Parameter to Estimate Age in Puppies in Veterinary Forensic Pathology

“…Currently, there is no single method universally accepted; indeed, most of them are highly influenced by breed, sex, nutritional [ 45 ], hormonal, and pathological changes [ 45 ] and even from the preservation of the corpse or remains. In veterinary medicine, the most widely used method in living animals is the visual examination of dental eruption [ 18 , 24 , 39 , 46 ]. This is a non-invasive method that can be easily performed by veterinarians, but it is influenced by a wide range of factors, including diet, habits, and breed variability [ 23 , 39 , 46 , 47 ].…”

“…For these reasons, veterinarians are increasingly demanded to precisely estimate the age of puppies. In veterinary literature [ 14 , 15 , 16 ], the main methods to evaluate the age of living puppies are the visual examination of the dentition, specifically the completeness of dental eruption and the extent of tooth wear [ 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 ]. Another technique based on teeth examination is counting dental cementum annuli [ 25 , 26 , 27 , 28 , 29 , 30 ]; cementum deposition starts at about the time of tooth emergence and, in mammals, there is the appearance of one annulus every year of the animal’s life.…”

“…Another age estimation method used in mammals is the evaluation of the skeletal age, specifically the radiographic appearance and formation of ossification centers in fore- and hind-limbs bones [ 31 , 32 , 33 , 34 , 35 , 36 , 37 ]. Moreover, these methods are affected by environmental factors, such as nutritional, hormonal, and pathological changes [ 14 , 18 , 38 , 39 ]. Previous studies in human glomerulogenesis showed that fetal mesangial and endothelial cells change their immunohistochemical expression of specific proteins, such as alpha smooth muscle actin (α-SMA), with maturation [ 40 ].…”

Post-Mortem Dental Profile as a Powerful Tool in Animal Forensic Investigations—A Review

“…The application of this method of age-at-death based on the evaluation of dental eruption is applied in humans only in children or young individuals; this situation must be considered in the case of some animals, for example the elephant, whose molars have an eruption sequence of 30 to 40 years [ 119 ]. Descriptive stages for dental development and eruption in relation to chronological age have been proposed in many animals of the order of carnivorous mammals such as canids (e.g., dog; [ 112 , 120 , 121 ]), felids (e.g., cat; [ 120 ]), and non-human Primates (e.g., lemur, galago, chimpanzee, gorilla, macaque; [ 122 , 123 , 124 , 125 ]), as well as ungulated mammals such as caprines (e.g., sheep, goat; [ 120 , 126 , 127 ]), bovids (e.g., cattle; [ 128 ]), and suids (e.g., pig; [ 120 , 129 ]), among others.…”