Data from: Severe enamel defects in wild Japanese macaques

Plane-form enamel hypoplasia (PFEH) is a severe dental defect in which
large areas of the crown are devoid of enamel. This condition is rare in
humans and even rarer in wild primates. The etiology of PFEH has been
linked to exposure to severe disease, malnutrition, environmental toxins,
and associated with systemic conditions. In this study, we examined the
prevalence of enamel hypoplasia in several populations of wild Japanese
macaques (Macaca fuscata) with the aim of providing context for severe
defects observed in macaques from Yakushima Island. We found that 10 of 21
individuals (48%) from Yakushima Island displayed uniform and significant
PFEH; all 10 specimens were from two adjacent locations in the south of
the island. In contrast, macaques from other islands and from mainland
Japan have low prevalence of the more common types of enamel hypoplasia
and none exhibit PFEH. In Yakushima macaques, every tooth type was
affected to varying degrees except for first molars and primary teeth, and
the mineral content of the remaining enamel in teeth with PFEH was normal
(i.e., no hypo- or hyper mineralization). The aetiology of PFEH might be
linked to extreme weather events or high rates of environmental fluoride
causing enamel breakdown. However, given that the affected individuals
underwent dental development during a period of substantial human-related
habitat change, an anthropogenic related etiology seems most likely.
Further research on living primate populations is needed to better
understand the causes of PFEH in wild primates.

平面型牙釉质发育不全（Plane-form enamel hypoplasia, PFEH）是一种严重的牙齿缺损病症，患者牙冠大面积缺失牙釉质。该病症在人类中较为罕见，在野生灵长类中更为少见。平面型牙釉质发育不全的病因被认为与重症疾病、营养不良、环境毒素暴露相关，同时也与全身性疾病存在关联。
本研究对多群野生日本猴（Macaca fuscata）的牙釉质发育不全患病率展开了调查，旨在为屋久岛猴群中观察到的严重缺损病例提供背景参考。研究发现，屋久岛的21个受检个体中有10只（占比48%）表现出均匀且显著的平面型牙釉质发育不全；这10个个体均来自该岛南部两处相邻的区域。与之形成对照的是，其他岛屿及日本本土的猴群中，常见类型牙釉质发育不全的患病率较低，且未出现任何平面型牙釉质发育不全病例。
在屋久岛野生日本猴中，除第一磨牙与乳牙外，所有牙型均存在不同程度的受累；且患平面型牙釉质发育不全的牙齿，其剩余牙釉质的矿物质含量处于正常水平，即未出现矿化不足或矿化过度的情况。
平面型牙釉质发育不全的病因可能与极端天气事件、高环境氟暴露导致的牙釉质破坏有关。但考虑到受影响个体的牙齿发育阶段正值人类活动引发生境发生显著改变的时期，人为相关的病因似乎可能性更高。
未来仍需对野生灵长类种群开展进一步研究，以更深入地阐明野生灵长类平面型牙釉质发育不全的致病原因。