Conclusion Nightguard vital tooth bleaching with TREE dental whitening gel is an effective, conveniency and safety therapy method and beneficial to periodontal tissue.

Study of shearer cutting mechanism is a vital issue, which is important to improve productivity, reduce energy consumption and knife tooth loss.

Around 21 years old, female Chi of kidney is very sufficient, wisdom tooth (usually called opsigenes) grows up gradually, girls have sufficient chi and blood and have a high color and be vital.