If the item you received is damaged or defective, Please Send message to me immidately. Our guarantee does not cover accidental damage or wear of product caused by customer. Thank you very much for your understanding! We're one of the largest online dental suppliers based on many qualified manufacturers in china.If you Send message to me immediately after placing the order, we will make every effort to assist you with your change request. Any help, need or questions, please do not hesitate to Send message to me. Looking forward to our friendly & win-win cooperation! The sale of this item may be subject to regulation by the U. Food and Drug Administration and state and local regulatory agencies.