CONCLUSION: the tooth type or tooth position, root curvature and calcification have significantly influenced the outcome of root canal treatment.
结论：根管治疗的失败与牙位(牙类型和牙位置)、根管弯曲度和钙化度密切相关。
2
Conclusion: high fluoride and low nourishment would cause underdevelopment of tooth matrix firstly, then affect the calcification of matrix, finally deteriorate the quality of teeth.
结论：高氟低蛋白营养首先影响牙基质的发育，进一步影响矿化，从而使牙齿整体发育不良，过度磨损。
3
The patient had been in childhood (calcification period of tooth development) using the tetracycline class of drugs, resulting in discoloration of the teeth.