CUSIP No. 703395103  13G/A  Page 1 of 5 Pages 

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION 

Washington, D.C. 20549

SCHEDULE 13G/A

Under the Securities Exchange Act of 1934

(Amendment No. 3)*

Patterson Companies, Inc.

(Name of Issuer)

Common Stock, $0.01 par value

(Title of Class of Securities)

703395103

(CUSIP Number)

December 31, 2010

(Date of Event Which Requires Filing of this Statement) 

Check the appropriate box to designate the rule pursuant to which this Schedule is filed: 

x  Rule 13d-1(b) 

¨  Rule 13d-1(c) 

¨  Rule 13d-1(d) 

*The remainder of this cover page shall be filled out for a reporting person’s initial filing on this form 

with respect to the subject class of securities, and for any subsequent amendment containing 

information which would alter the disclosures provided in a prior cover page. 

The information required in the remainder of this cover page shall not be deemed to be “filed” for the 

purpose of Section 18 of the Securities Exchange Act of 1934 (“Act”) or otherwise subject to the 

liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see 

the Notes). 

CUSIP No. 703395103  13G/A  Page 2 of 5 Pages 

1.	Name of Reporting Persons.
	I.R.S. Identification No. of above persons (entities only).
	Delaware Charter Guarantee & Trust Company dba Principal Trust Company as
	Trustee for the Patterson Companies, Inc. Employee Stock Ownership Plan, IRS No.
	51-0099493.

2.	Check the Appropriate Box if a Member of a Group:
	(a) ¨
	(b) ¨

3. SEC Use Only 

4.	Citizenship or Place of Organization:
	Delaware

Number of Shares Beneficially Owned by Each Reporting Person With:
	5. Sole Voting Power:
	0
Number of	6. Shared Voting Power:
Shares	19,156,115
Beneficially	7. Sole Dispositive Power:
Owned By	0
Each	8. Shared Dispositive Power:
Reporting	19,156,115
Person With:
9. Aggregate Amount Beneficially owned by Each Reporting Person
19,156,115
10. Check if Aggregate Amount in Row (9) Excludes Certain Shares:
¨
11. Percent of Class Represented by Amount in Row (9):
15.57%
12. Type of Reporting Person:
EP

CUSIP No. 703395103  13G/A  Page 3 of 5 Pages 

Item 1.
(a) Name of Issuer:			Patterson Companies, Inc.
(b) Address of Issuer’s Principal Executive Offices:			1031 Mendota Heights Road
			Saint Paul, MN 55120-1419
Item 2.
(a) – (c) Name, Principal Business Address and Citizenship of Person Filing:
Delaware Charter Guarantee & Trust Company dba Principal Trust Company as Trustee
for the Patterson Companies, Inc. Employee Stock Ownership Plan
1013 Centre Road
Wilmington, Delaware 19805
Citizenship:	Delaware
(d) Title of Class of Securities:		Common Stock, $0.01 par value
(e) CUSIP Number:		703395103
Item 3. If this statement is filed pursuant to Rule 13D-1(b) or 13D-2(b) or (c), check whether the
person filing is a:
(f) x An employee benefit plan or endowment fund in accordance with Rule 13d-1(b)(1)(ii)(F);
Item 4. Ownership - Provide the following information regarding the aggregate number and
percentage of the class of securities of the issuer identified in Item 1.
(a) The Patterson Companies, Inc. Employee Stock Ownership Plan (“Plan”) is subject to the
Employee Retirement Income Security Act of 1974 (“ERISA”). Delaware Charter Guarantee
& Trust Company dba Principal Trust Company acts as the Trustee of the Patterson
Companies, Inc. Employee Stock Ownership Plan Trust (“Trust”). As of December 31, 2010,
the Plan held 19,156,115 shares of the Issuer’s common stock. The securities reported
include all shares held of record by the Trustee. The Trustee follows the directions of the
Employer, Patterson Companies (the “Employer”), or other parties designated in the trust
agreement between the Employer and the Trustee, with respect to voting and disposition of
shares. The Trustee, however, is subject to fiduciary duties under ERISA. The Trustee
disclaims beneficial ownership of the shares of common stock that are the subject of this
Schedule 13G.
(b) The 19,156,115 shares of common stock represent 15.57% of the Issuer’s outstanding shares
of common stock. The percent of class is based on shares outstanding as of December 31,
2010, as provided by the Issuer.

CUSIP No. 703395103  13G/A  Page 4 of 5 Pages 

(c) Number of shares as to which such person has:
(i)	Sole power to vote or direct the vote: 0
(ii)	Shared power to vote or direct the vote: 19,156,115
(iii)	Sole power to dispose or direct the disposition of: 0
(iv)	Shared power to dispose or direct the disposition of: 19,156,115
Item 5. Ownership of Five Percent or Less of Class
Not Applicable
Item 6. Ownership of More Than Five Percent on Behalf of Another Person
Not Applicable
Item 7. Identification and Classification of the Subsidiary Which Acquired the Security Being
Reported on by the Parent Holding Company
Not Applicable
Item 8. Identification and Classification of Members of the Group
Not Applicable
Item 9. Notice of Dissolution of Group
Not Applicable
Item 10. Certification
By signing below I certify that, to the best of my knowledge and belief, the securities referred to above
were acquired and are held in the ordinary course of business and were not acquired and are not held
for the purpose of or with the effect of having or influencing the control of the issuer of the securities
and are not acquired and are not held in connection with or as a participant in any transaction having
that purpose or effect.

CUSIP No. 703395103  13G/A  Page 5 of 5 Pages 

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set 

forth in this statement is true, complete and correct. 

Delaware Charter Guarantee & Trust Company 

/s/ Kristin M. Camp_________________ 

Kristin M. Camp 

Vice President, Operations 

January 24, 2011