Wallis Corrin, Solmi Francesca, Pesci Ilaria, Desforges Neil, Holcombe Lucy J
Waltham Petcare Science Institute, Waltham-on-the-Wolds, Leicestershire LE14 4RT, UK.
Interuniversity Institute for Biostatistics and Statistical Bioinformatics (I-Biostat), Data Science, Hasselt University, 3500 Hasselt, Belgium.
Vet Sci. 2023 Jun 21;10(7):406. doi: 10.3390/vetsci10070406.
The development of dentition in dogs has been associated with several problems including tooth over-crowding, missing permanent dentition, and persistent deciduous teeth (PDT). Information on dentition development in different breeds is lacking. This study of 61 Yorkshire terriers aimed to determine the (i) average age at deciduous tooth exfoliation, (ii) average age at permanent tooth eruption, (iii) PDT incidence, and influencing factors such as body weight. The ages of exfoliation of deciduous teeth and eruption of permanent dentition were influenced by body weight and tooth type. These dentition changes tended to occur later in dogs ≤ 3 kg versus dogs > 5 kg. Generally, incisors were exfoliated first, followed by premolars and then canines. At a body weight of 4.5 kg, the middle of the data range, the estimated age at loss of deciduous teeth (with 95% confidence intervals) was 21.9 (21.1, 22.9) weeks for incisors, 26.1 (24.9, 27.4) weeks for canines, and 23.9 (22.9, 24.9) weeks for premolar. The estimated age at eruption of permanent dentition was 22.3 (21.6, 23.0) weeks for incisors, 23.8 (23.0, 24.6) weeks for canines, 24.7 (24.0, 25.5) weeks for premolars, and 26.4 (25.5, 27.3) for molar teeth. However, this sequence was disrupted in dogs ≤ 3 kg. Yorkshire terriers had a high incidence of PDT. At a body weight of 4.5 kg, the estimated proportion of PDT was: incisors 0.86% (0.32, 2.31), canines 15.62% (7.62, 29.37) and premolars 3.57% (1.62, 7.66). Canines constituted the most frequently retained tooth type, with 89.1% retained in dogs ≤ 3 kg compared to 12.0% in dogs > 5 kg. This information will enable veterinarians to provide personalised advice regarding the oral care requirements for Yorkshire terriers and highlights the need to regularly monitor this breed between the ages of two and seven months, during the active phases of tooth development.
犬齿列的发育与多个问题相关，包括牙齿过度拥挤、恒牙列缺失和乳牙滞留（PDT）。目前缺乏不同犬种齿列发育的相关信息。这项对61只约克夏梗犬的研究旨在确定：（i）乳牙脱落的平均年龄；（ii）恒牙萌出的平均年龄；（iii）乳牙滞留发生率以及体重等影响因素。乳牙脱落和恒牙萌出的年龄受体重和牙齿类型影响。体重≤3千克的犬与体重>5千克的犬相比，这些齿列变化往往发生得更晚。一般来说，门牙最先脱落，其次是前磨牙，然后是犬齿。在体重4.5千克（数据范围的中间值）时，乳牙脱落的估计年龄（95%置信区间）为：门牙21.9（21.1，22.9）周，犬齿26.1（24.9，27.4）周，前磨牙23.9（22.9，24.9）周。恒牙萌出的估计年龄为：门牙22.3（21.6，23.0）周，犬齿23.8（23.0，24.6）周，前磨牙24.7（24.0，25.5）周，磨牙26.4（25.5，27.3）周。然而，在体重≤3千克的犬中，这个顺序被打乱。约克夏梗犬乳牙滞留的发生率较高。在体重4.5千克时，乳牙滞留的估计比例为：门牙0.86%（0.32，2.31），犬齿15.62%（7.62，29.37），前磨牙3.57%（1.62，7.66）。犬齿是最常滞留的牙齿类型，体重≤3千克的犬中有89.1%的犬齿滞留，而体重>5千克的犬中这一比例为12.0%。这些信息将使兽医能够就约克夏梗犬的口腔护理需求提供个性化建议，并突出了在牙齿发育活跃阶段，即两到七个月大期间对该犬种进行定期监测的必要性。
