Permanent Tooth Eruption Patterns in Nigerian Local Pigs.

Pigs are diphyodonts with heterodont dentition and have been used in studies involving teeth and jawbone regeneration, and dental implants. Patterns of tooth eruption are used to age animals and determine the effects of environmental and genetic influences on occurrence of variations. As with other species, variations exist in the tooth eruption pattern in pigs. The aim of this study was to determine the permanent teeth eruption patterns of Nigerian local pigs. Twenty-six healthy pigs were observed throughout the study period. Pigs were firmly held in dorsal or lateral recumbency and their mouths gently held open to visually examine all quadrants of the dental arches (right and left maxillary, right and left mandibular). Observations were recorded from 16 weeks of age, until the last permanent tooth erupted. Results obtained from the study showed that males had lower mean values for eruption time (54%) of examined teeth in comparison to females. The mean values of eruption time for the maxillary third incisor, the mandibular and maxillary canines, and the mandibular fourth premolar teeth were statistically significant in the males (= .0017, = .0088, = .0002 and = .0244, respectively). Sixty-nine percent of the adult pigs did not have eruption of the mandibular first premolar, while polydontia was observed in the maxillary and mandibular incisors. These results show that intra-breed and inter-breed variations exist in the dental eruption pattern in pigs. The data obtained from this study can be used for comparative dental studies and can aid further research on the developmental anatomy of Nigerian local pigs.