Karleen Sirrine brings 32 years of extensive dental industry experience to her role as a Business Coach. Karleen's diverse background spans solo practices, specialist offices, and multi-location oversight within the DSO space. Outside of work, she relishes outdoor adventures with her family. What she finds most fulfilling in coaching is helping clients expand their perspectives, set strategic goals, and achieve success, allowing them to unlock their full potential in dentistry and beyond.

Barb has been involved with Tier Three since its early days, officially joining full-time over a decade ago. She began by supporting appraisals and management and transitioned into a Sales Representative role in 2014. With a lifelong connection to the dental industry and decades of hands-on experience, Barb offers clients a deep understanding of practice transitions and a strong commitment to service. Her longstanding involvement with Tier Three makes her a trusted resource for both buyers and sellers.

Over the past decade, Greg has become one of Tier Three’s leading valuation experts, supporting Transition Sales Consultants nationwide. His deep understanding of dental practice valuation and strong attention to detail make him a trusted resource for clients and colleagues alike. Before joining Tier Three, Greg spent over five years in product logistics, bringing a strong foundation in process and analysis to his current role.

Lee Tessler delivers many lectures to doctors across the country. Topics include opening a practice, expansions, relocations, lease renewals and doctors looking to transition out of dentistry. Lee is originally from the UK has been consulting and advising healthcare professionals since the late 90’s with an emphasis on risk mitigation, wealth management, commercial real estate and wealth/estate protection.