SEC Form 4

FORM 4		UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940	OMB APPROVAL OMB Number: 3235-0287 Estimated average burden hours per response: 0.5
X	Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

1. Name and Address of Reporting Person* Sirona Holdings Luxco S.C.A. (Last) (First) (Middle) 412F, ROUTE D??ESCH (Street) L-1030 N4 (City) (State) (Zip)	2. Issuer Name and Ticker or Trading Symbol SIRONA DENTAL SYSTEMS, INC. [ SIRO ]	5. Relationship of Reporting Person(s) to Issuer (Check all applicable) Director X 10% Owner Officer (give title below) Other (specify below)
	3. Date of Earliest Transaction (Month/Day/Year) 05/13/2011
	4. If Amendment, Date of Original Filed (Month/Day/Year)	6. Individual or Joint/Group Filing (Check Applicable Line) Form filed by One Reporting Person X Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Stock	05/13/2011		S		9,747,480	D	$53	0	D(1)

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares

1. Name and Address of Reporting Person* Sirona Holdings Luxco S.C.A. (Last) (First) (Middle) 412F, ROUTE D??ESCH (Street) L-1030 N4 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* Sirona Holdings S.A. (Last) (First) (Middle) 412F, ROUTE D??ESCH (Street) L-1030 N4 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* MDCP GLOBAL AGGREGATOR, L.P. (Last) (First) (Middle) C/O MADISON DEARBORN PARTNERS, LLC THREE FIRST NATIONAL PLAZA, SUITE 4600 (Street) CHICAGO IL 60602 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* MDCP IV Global Investments LP (Last) (First) (Middle) MAPLES CORPORATE SERVICES LTD, PO BOX309 UNITED HOUSE, SOUTH CHURCH STREET (Street) GEORGE TOWN, GRAND CAYMAN E9 KY-1104 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* MDCP IV Global GP, LP (Last) (First) (Middle) MAPLES CORPORATE SERVICES LTD, PO BOX309 UNITED HOUSE, SOUTH CHURCH STREET (Street) GEORGE TOWN, GRAND CAYMAN E9 KY-1104 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* MDP Global Investors LTD (Last) (First) (Middle) MAPLES CORPORATE SERVICES LTD, PO BOX309 UNITED HOUSE, SOUTH CHURCH STREET (Street) GEORGE TOWN, GRAND CAYMAN E9 KY-1104 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

Explanation of Responses:

1. The following entities may be deemed to have a beneficial interest in the Common Stock held by Sirona Holdings Luxco S.C.A. ("Luxco"): Sirona Holdings S.A by virtue of its being the sole manager of Luxco; MDCP Global Aggregator, L.P. ("MDCP Global Aggregator") by virtue of its being the controlling shareholder of Luxco; MDCP IV Global Investments LP by virtue of its being the controlling shareholder of Sirona Holdings S.A.; MDP IV Global GP, LP by virtue of its being the sole general partner of MDCP IV Global Investments LP; and MDP Global Investors Limited, by virtue of its being the sole general partner of MDP IV Global GP, LP and MDCP Global Aggregator. Each of MDCP Global Aggregator, MDCP IV Global Investments LP, MDP IV Global GP, LP and MDP Global Investors Limited disclaims beneficial ownership of any shares directly held by Luxco, except to the extent of their respective pecuniary interests therein.

	/s/ Timothy Sullivan, its 'A' Director, Sirona Holdings S.A., its Manager for Sirona Holdings Luxco S.C.A.	05/16/2011
	/s/ Timothy Sullivan, its 'A' Director for Sirona Holdings S.A.	05/16/2011
	/s/ Timothy Sullivan, its Managing Director, MDP Global Investors Limited, its General Partner for MDCP Global Aggregator, L.P.	05/16/2011
	/s/ Timothy Sullivan, its Managing Director, MDP Global Investors Limited, its General Partner, MDP IV Global GP, LP, its General Partner for MDCP IV Global Investments LP	05/16/2011
	/s/ Timothy Sullivan, its Managing Director, MDP Global Investors Limited, its General Partner for MDP IV Global GP	05/16/2011
	/s/ Timothy Sullivan, its Managing Director for MDP Global Investors Limited	05/16/2011
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
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