UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.F. 20549 SCHEDULE 13G ALIGN TECHNOLOGY INC. Common Stock 016255101 Item 1. a. Align Technology Inc. b. 881 Martin Avenue Santa Clara, CA 95050 Item 2. a. D.F. Dent & Company, Inc. b. 2 East Read Street, 6th Floor Baltimore, Maryland 21202 c. Incorporated in the State of Maryland d. Common stock e. 016255101 Item 3. Investment adviser registered under section 203 of the Investment Advisers Act of 1940 Item 4. a. 3,516,441 b. 5.03% c. 1. 3,516,441 2. 0 3. 3,516,441 4. 0 Item 5. N/A Item 6. N/A Item 7. N/A Item 8. N/A Item 9. N/A