Our Team

About Our Office

Greeley Dental Health is located in Greeley, Colorado. Our team of dental specialists includes regular and cosmetic dentists and an endodontist.

Before your first appointment, check our insurances accepted page to see if we take your insurance, or review our options for patients who don’t have dental insurance.

Dr. Charles Johnson, DDS

Dr Charles Johnson

Dr. Charles Johnson is a graduate of the University of Nebraska School of Dentistry. In 1979 he received his undergraduate Bachelor of Science degree from Brigham Young University in Provo, Utah. He has been a practicing General Dentist for over 22 years and 18 of those years were spent here in Greeley. Dr. Johnson completed a one-year general dentistry postgraduate hospital residency program in California and then moved to Colorado in 1994. He practiced first in Denver, then in Longmont, and for the last 16 years in Greeley. He has been practicing with Greeley Dental Health since its inception in October 1997. He has completed advanced training in C02 laser surgery and implants.

Dr. Johnson is especially concerned with patient education and disease/decay prevention. Oral health is an important aspect of a person’s general well-being. It can significantly improve the quality of life if it is maintained. He believes in a team effort approach to dental care where the patient and doctor mutually decide and work together to meet the goals of obtaining and maintaining good oral health.

Dr. Johnson is a graduate of Cerinate Smile Design and the Academy of Laser Dentistry in the use of the DEKA Ultraspeed CO2 laser.

Dr. Seth Klasko – General Dentist

Dr. Seth KlaskoDr. Klasko is from Phoenix, Arizona and graduated from Northern Arizona University with a Bachelor of Science in Biology and Chemistry. He studied at Midwestern University, one of the most technologically advanced dental schools in the nation.

Dr. Klasko enjoys treating patients of all ages and levels of need. His particular areas of interests include crown and bridge, extractions, bone graft, and general cosmetic dentistry. His favorite part of being a dentist is building relationships with patients and changing the way patients feel about going to the dentist. In his spare time Dr. Klasko enjoys skiing, camping, and mountain biking.

Dr. Klasko’s positive, upbeat energy is contagious and we are so happy to have him as part of our Team.

Dr. Chelsea Twohig, Periodontist

Dr. Chelsea TwohigDr. Twohig was born and raised in small-town Wisconsin.  She attended the University of Wisconsin-Madison, graduating with a Bachelor of Science in Biology and Spanish.  Rather than immediately entering dental school, Dr. Twohig pursued her passion for Spanish language and culture, spending two years in northern Spain as an English language assistant in high school classrooms.  It was during those two years that Dr. Twohig began to play ultimate Frisbee, which has become the pastime that dominates her free time to this day.

Although Dr. Twohig fell in love with Spain, she felt it time to return to the US and begin the next phase of her academic and professional life, and so she enrolled in the University of Iowa College of Dentistry.  Prior to her periodontal residency program, in the interest of developing her ability to practice dentistry in Spanish, Dr. Twohig completed a two year advanced education in general dentistry residency at the University of Puerto Rico School of Dental Medicine.  She then completed her periodontal residency at Oregon Health and Science University.  Dr. Twohig enjoys all aspects of her work, but specifically enjoys forming relationships with her patients and colleagues.

She and her husband, Derek, recently moved to Colorado as Derek accepted a position at the University of Northern Colorado.  Together they enjoy traveling, snowboarding, and ultimate Frisbee.


Wendy – Office Manager


Roxanne – Insurance and Billing


Heather – Front Desk


Hillary – RDH


Tyler – RDH


Arturo – DA


Rosalba – DA


Tammie – DA