Abstract：
We used fluorochrome labeling to study spatiotemporal variation of dentin apposition (DAR) and extension (DER) rates during crown and root formation of mandibular first molars from wild boar and domestic pigs. DAR was reconstructed along the course of dentinal tubules in four zones of the crown and in the upper root area. In all five zones, mean DAR increased during the first 30% to 40% of apposition, reaching highest values (22-23 μm/day) in the upper-lateral crown zone. Lowest values were recorded near the dentin-pulp interface (DPI). Typically, DARs in contemporaneously formed dentin areas were higher in more cuspally compared to more cervically/apically located zones. DER was high (>200 μm/day) in early postnatal crown dentin and then decreased markedly in cervical direction, with lowest values in the cervical crown zone. After this nadir, DER sharply increased in the upper 30% to 40% of the root extension, reaching values equaling (wild boar) or even surpassing (domestic pigs) those recorded in the upper lateral crown. After this peak, DER again decreased. While DAR did not differ markedly between wild boar and domestic pigs, the DER showed marked differences, both regarding maximum values (208.1 μm/day in wild boar, 272.2 μm/day in domestic pigs) and the timing of the root growth spurt, which occurred earlier in the domestic pigs. We consider the more rapid recruitment of secretory odontoblasts in domestic pigs (reflected by higher DER) a side effect of selection for rapid body growth during pig domestication.
摘要：
我们使用荧光染料标记研究了野猪和家猪下颌第一磨牙的冠和根形成过程中牙本质并置（DAR）和扩展（DER）速率的时空变化。沿着牙冠的四个区域和上根区域的牙本质小管重建DAR。在所有五个区域中，平均DAR在并置的前30%到40%期间增加，在上外侧冠区达到最高值（22-23μm/天）。在牙本质-牙髓界面(DPI)附近记录到最低值。通常,与更多位于宫颈/顶部的区域相比，在更尖端的牙本质区域中，同时形成的牙本质区域的DAR更高。出生后早期牙冠牙本质的DER较高（>200μm/天），然后在子宫颈方向上明显下降，在颈冠区有最低值。在这个最低点之后,DER在根部延伸的上部30％至40％急剧增加，达到等于（野猪）甚至超过（家猪）上侧冠记录的值。在这个高峰之后，DER再次下降。虽然DAR在野猪和家猪之间没有显着差异，DER显示出明显的差异，两者都关于最大值(野猪208.1μm/天，家猪的272.2μm/天）和根系生长突增的时间，这发生在家猪的早期。我们认为，在家猪中更快地招募分泌性成牙本质细胞（由较高的DER反映）是在猪驯化过程中选择快速身体生长的副作用。
