As it is branded as a "pain-free" and comfortable treatment, the pain and discomfort for the first few days was barely tolerable. Yet I got used to its presence since the fourth/fifth day. I suggest the customer service staff can give honest warnings to customers first. Another point that bothered me was the arrangement of fitting after the removal of my wisdom tooth. I appreciate that the dentist has suggested me many ways to treat my teeth problems first before the commencement of Zenyum treatment so as to maximize my gains. However, I was a bit disappointed that only when my right upper part gum sore a lot can I found out that the removed Right Upper Wisdom Tooth was not taken into consideration in the moulding of my tailor-made retainer. Fortunately, the customer service staff Janice has reacted quickly to help me receive the fit-sized retainers. Nonetheless, my smile do look better in shorter period of time than I expected. I look forward to the better smile that Zenyum will bring me. Thanks.