Dental Staff

  • David Strange, DDS, MS

    Dr. David Strange has lived in Colorado since 1977. He attended grade school and high school on the 'west' side of town and graduated from the University of Colorado at Boulder. The foothills of Golden and the flatirons of Boulder are truly home to him. When he isn't in the offices playing with the children, a privilege he tries to convince the rest of us is actually work, you can find him on the slopes of Copper Mountain or at a crowded Folsom stadium watching his beloved Colorado Buffaloes.

    Dr. Strange and his wife, Erin, live in Golden with their three children, Clara, Marshall and Sullivan. Clara loves to dance competitively, and play golf; Marshall loves to play football, baseball, golf, soccer, and basketball; and Sullivan competes in the the same sports his older brother does. The three kids enjoy skiing and snowboarding whenever the dance and sports schedules allow. The family is active in the children's school, extracurricular activities and church. They also love to travel as much as having three active children will allow.

    Dr. Strange graduated from the University of Colorado at Boulder in 1994 with a BS degree in biology and the University of Colorado School of Dentistry in 1998 with the DDS degree. He then completed the Pediatric Dental Residency Program at Baylor College of Dentistry in Dallas, Texas where he earned the degree of Master of Science in 2000. His master's thesis was on the subject of 'Primary Tooth Pulp Therapy.'

    Dr. Strange has very fond memories of going to work with his father, who was a strong influence in his life. Following in his father's footsteps to become a pediatric dentist was a natural decision for him. It was a decision on which he has never looked back. Dr. Strange joined the Pediatric Dental Group of Colorado in 2000 after completing his pediatric dental specialty training. He practices in all of the offices but is known to schedule himself in the Frisco office on Friday to conveniently turn that trip into a ski weekend.

  • Justin Cathers, DDS

    Dr. Justin Cathers is a native of Colorado. After graduating Magna Cum Laude from Colorado State University with a B.S. in Biology, Dr. Cathers began his dental training at the University of Colorado Health Sciences Center in Denver. Upon completion of his DDS degree with honors in 2001, he continued on to receive his Master's Degree in pediatric dentistry from Baylor University in Dallas. While at Baylor, Dr. Cathers conducted a study comparing the effectiveness of various sedation methods for pediatric patients. His work was published in The Journal for the American of Pediatric Dentistry. Dr. Cathers worked at Texas Scottish Rite Hospital for Children, Children's Medical in Dallas, and Mesquite Community Hospital, serving the diverse dental needs of children with various conditions.

    After his pediatric residency was completed, Dr. Cathers returned to Colorado where he practiced for the past five years, and recently served as the President of the Colorado Association of Pediatric Dentists. He enjoyed his time working for the Pediatric Dentist he went to growing up, and creating positive dental experiences for his patients. Dr. Cathers is a member of the American Academy of Pediatric Dentistry, the American Dental Association, the Colorado Association of Pediatric Dentists, the Southwestern Society of Pediatric Dentistry, and the New York State Dental Association.

    Over the years, Dr. Cathers has spent time volunteering at health fairs and creating presentations for schools stressing the importance of early dental care. When not tending to the needs of his patients, Dr. Cathers enjoys spending time with his wife and children skiing, gardening, hiking, and traveling.

  • Ashley Underwood, DMD, MS

    Dr. Ashley Underwood is a native of Colorado, growing up on the Front Range (Colorado Springs and Centennial). She attended the University of San Diego, where she captained the school's women's lacrosse team and earned her bachelor's degree in Communications. After working as an orthodontic assistant for two years back in Colorado, she attended the University of Louisville School of Dentistry in Louisville, Kentucky, obtaining her doctor of medical dentistry degree. Following her dental school training she was accepted immediately into the pediatric specialty residency at Indiana University in Indianapolis, Indiana. She trained at the Riley Hospital for Children, one of the top children's hospitals in the nation. Dr. Underwood's master's thesis was on the 'Development of Subsequent Primary and Secondary Caries in Children Receiving Comprehensive Dental Treatment on Multiple Occasions Under General Anesthesia.'

    During her residency, Dr. Underwood still managed to participate in dental mission trips to Mexico, where she performed dental work on Mayan children in the jungles of the Yucatan peninsula.

    Dr. Underwood is proud to be a member of the American Dental Association, the American Academy of Pediatric Dentistry and is Board Certified by the American Board of Pediatric Dentistry.

    Dr. Underwood is thrilled to be back in Colorado with her family and friends and to have the opportunity to join the Pediatric Dental Group of Colorado. Dr. Underwood understands her important role in establishing habits that will affect her patients throughout their lives and will enable them to be healthy and feel confident. She is inspired by the idea of making a trip to the dentist not just bearable, but fun!

    Dr. Underwood and her husband have two young daughters. In her spare time, she enjoys running, cheering on the Denver Broncos, spending time with her family, traveling, and skiing.

  • Malcolm Strange, DDS, MSD

    Malcolm Strange, DDS, MSD, moved his family from Texas to Colorado in 1977. He and his wife, Judy, raised two sons in Colorado. They have been active in their community and church for 35 years. They are both avid Denver Bronco and Colorado Avalanche fans and enjoy the Colorado lifestyle, spending many days skiing or snowmobiling with their family in the Summit County area. They now look forward to repeating their Colorado experiences through the eyes of their grandchildren.

    Prior to entering the field of dentistry, he received a Bachelor of Science degree in Electrical Engineering at the University of Texas. Dr. Strange began his dental training at Baylor College of Dentistry where he received his DDS degree. This was followed by a two year pediatric dental residency at Children's Medical Center in Dallas, Texas where he earned his Master of Science degree. With these accomplishments completed, Dr. Strange began his career as a solo practitioner in Wheat Ridge and Evergreen, Colorado in 1977.

    After beginning his pediatric dental career in Wheat Ridge and Evergreen, Dr. Strange established additional practices in Frisco in 1996; Lafayette in 2004; and Greeley in 2008. Dr. Malcolm Strange is the founding and senior member of the Pediatric Dental Group. He has the respect and admiration of his peers and of those he has influenced. He has passed his knowledge and passion for children's dentistry on to a multitude of dentists and specialists throughout Colorado and the country.

    Dr. Strange is a Board Certified Pediatric Dentist and a Diplomate of the American Board of Pediatric Dentistry. Dr. Strange maintains memberships with the American Dental Association, American Academy of Pediatric Dentistry, Colorado Dental Association, Metropolitan Denver Dental Society, and Southwest Society of Pediatric Dentistry. He is an Associate Clinical Professor at the University of Colorado School of Dentistry where he serves as a preceptor on the Advanced Clinical Training and Service Program.

    Dr. Strange primarily practices at the Wheat Ridge and Evergreen offices. He currently has staff privileges at Exempla Lutheran Medical Center and St. Anthony Summit Medical Center.

  • Ann Hoang, DMD

    Dr. Ann Hoang was born and raised in Orlando, Florida. She attended the University of Florida and was accepted into the Honors Combined BS/DMD program where in 7 years she received both her bachelors degree in Nutrition and her Doctor of Dental Medicine degree. She went on to complete her pediatric dentistry residency at the Children's Hospital Colorado located in Aurora, CO. Children's Hospital Colorado has been continually ranked as one of the top children's hospitals in the nation, and Dr. Hoang was able to help kids all across Colorado and the west during her two years of training.

    Dr. Hoang has had the special blessing of growing up with a brother with autism. Her older brother, Tuan, inspired her in numerous aspects of her life. She credits Tuan to teaching her patience, empathy, and the enjoyment of the simple things in life. Tuan was the original inspiration in her decision to pursue dentistry as a career in the first place, and is an overarching reason why her interests now lie in pediatric dentistry and in the treatment of children with special needs.

    Dr. Hoang can see no more rewarding future for herself than one as a caring pediatric dentist. She is grateful for the opportunity to use her unique experiences and training to be the last stop for a family hoping to find care for their children. She believes that with her patience, understanding and energetic attitude, she can ensure that the children in the community have dental experiences growing up that are fun and pleasant ones and can lay the foundation for maintaining a dental home for life.

    The crisp mountain air and 300 days of sunshine kept Dr. Hoang in the Denver area where she is excited to escape the 100% humidity and mosquitoes back in Florida. When she is otherwise not working on building tolerance for the colder weather, you can find her falling in love with the Rocky Mountains, hiking, snowboarding, or playing tennis. In the fall you can also catch her on Saturday's at Jackson's rooting for her beloved Florida Gators!

  • Nikki Darbani, DDS

    Dr. Nikki Darbani was born and raised in Jacksonville, Florida. In 2009, she moved to Gainesville, Florida better known as “The Swamp” to attend the University of Florida for undergrad, go Gators! There, she earned her Bachelor of Science degree in Food Science and Nutrition in 2013, graduating Magna Cum Laude.  Following college, Dr. Nikki made the leap out to Los Angeles, California where she attended the University of Southern California and earned her Doctorate of Dental Surgery degree. Dr. Nikki was actively involved in various dental outreach programs to better serve the pediatric population across the globe, including the Philippines, Mexico, Belize, and Cambodia. After dental school, she returned back to Florida to specialize in pediatric dentistry at her alma mater, the University of Florida. 

    Dr. Nikki is board-eligible by the American Board of Pediatric Dentistry and maintains active membership with several local, state, and national dental organizations including the American Academy of Pediatric Dentistry, the American Dental Association, Colorado Dental Association, and Colorado Academy of Pediatric Dentistry.

    Dr. Nikki is dedicated to creating positive dental experiences for her patients at a young age in order to give kids an advantage not only in their oral health but also in their future development. She specializes in behavior management and anxiety relief for children to provide each child with a fun dental experience while in a caring environment. Dr. Nikki truly believes that educating her patients and their families on exceptional oral health is the key to a happy, healthy smile!

    Dr. Nikki is thrilled to be providing care for the infants, children, and teenagers in Colorado and privileged to have the opportunity to join the Pediatric Dental Group of Colorado. When not in the office, Dr. Nikki enjoys spending time with her family and friends, traveling, hiking, skiing, long walks with her active puppy named Benji and, of course, cheering on the Florida Gators!

  • Paul Regan, DMD

    Dr. Regan has been setting the highest standards of excellence in orthodontics for over 20 years! A graduate of the University of Connecticut School of Dental Medicine, Dr. Regan completed a general practice residency at Tufts University and practiced dentistry for seven years before specializing and earning his certification in orthodontics at the Eastman Dental Center at the University of Rochester.

    An esteemed member of the orthodontic community, Dr. Regan is a member of many leading dental organizations, including the:

    • American Dental Association
    • Colorado Dental Association
    • Metropolitan Denver Dental Society
    • Colorado Association of Orthodontists
    • Colorado Summer Meeting (past president and board member)

    Dr. Regan and his wife, Marge, a former PTA president, have lived in Evergreen since 1990 and have raised three daughters here. He is a member of Christ the King Catholic Church, and supports many local groups and sports teams. In his spare time, he enjoys the beauty of Colorado - fly fishing, hiking, excercising, and working outdoors.

  • Craig Shellhart, DDS

    Dr. Craig Shellhart is an “almost native” of Colorado, having been born in Lawrence, Kansas, then moving here when he was 3 months old. He grew up enjoying the many opportunities of the Colorado outdoors and continues to love living in Colorado.

    Dr. Shellhart attended college at Colorado State University and dental school at the University of Colorado. He practiced general dentistry for 4 years then completed his orthodontic residency at the University of Nebraska. He taught at the University of Kentucky College of Dentistry in Lexington, Kentucky for 7 years. In 1995, he was delighted to have the opportunity to return to the Denver area to teach at the University of Colorado School of Dental Medicine. He was thrilled to have the opportunity to join the Pediatric Dental Group of Colorado starting in 2003.

    Dr. Shellhart is a Board Certified Orthodontist and is a reviewer for two orthodontic journals. He is actively involved in orthodontic research and he has published more than thirty articles related to orthodontics. He is a member of Omicron Kappa Upsilon (Dental Honor Society), American Dental Educators Association, American Association of Orthodontists, Colorado Orthodontic Association, the Rocky Mountain Society of Orthodontists, the Metropolitan Denver Dental Society, and the Colorado Dental Association.

    Dr. Shellhart finds his work in orthodontics highly rewarding and satisfying. He feels very fortunate to have the opportunity to be both a part of the Pediatric Dental Group of Colorado and to teach at the University of Colorado School of Dental Medicine.

    Dr. Shellhart and his wife, Cami, reside in Littleton, Colorado. They have two wonderful daughters. Dr. Shellhart enjoys spending time with his family and three dogs, traveling, reading, fishing, exploring national parks, and biking in the foothills.

  • Robert Craig, DDS, MS

    Dr. Craig was born in Garden City, Kansas. He is a graduate of Washburn University in Topeka. After a brief tour in the U.S. Navy as a dental technician, Dr. Craig attended dental school at the University of Missouri/Kansas City, where he received his Doctor of Dental Surgery degree with honors in 1980. Following graduation, he entered military service in the U.S. Air Force as a general dentist.

    After several years of practice in the Air Force, Dr. Craig was selected by the Air Force to pursue graduate studies in the specialty of Orthodontics. He attended Baylor College of Dentistry in Dallas, Texas, and earned a Master's Degree and Certificate in Orthodontics in 1995. Following his graduation, Dr. Craig returned to military life as a staff orthodontist at Travis AFB in California. During his tour, he was a support instructor for the Oral and Maxillofacial Surgery residency at David Grant Medical Center and was a training officer in orthodontics for the Advanced Education in General Dentistry residency.

    Dr. Craig is a member of several professional organizations including: Phi Kappa Phi Honor Society, Omicron Kappa Upsilon Honor Society, American Association of Orthodontists, Rocky Mountain Society of Orthodontists, American Dental Association, and the Colorado Dental Association.

    Dr. Craig is married and has two sons. He enjoys hiking, fishing, traveling, and spending time with his family. He has been in private practice in Colorado since 1995. He is excited about offering personalized, comprehensive orthodontic care with an experienced, caring staff.


The PDG Team

It can accurately be said that the heart and soul of the Pediatric Dental Group is the experienced, caring, and hard-working staff of forty dental team members. The Pediatric Dental Group currently has 3 licensed dental hygienists, 30 dental assistants and 20 front office personnel. Many of the Pediatric Dental Group employees have been with the company for longer than 15 years.

It can accurately be said that this is a group of committed and loyal dental team members who possess the compassion, skill and dedication to make the entire dental experience at the Pediatric Dental Group "Best in Class."

The staff at the Pediatric Dental Group is committed to providing the best possible dental care available to children in a loving and caring way. Most of the staff in the offices have children of their own and understand that children need to be encouraged and parents need to be reassured during the dental visit. They have been in the very same shoes as the parents who bring their children to see us at the Pediatric Dental Group. It is this perspective that we keep at the center of every decision we make. Our commitment to you is that we will treat you and your children the very same way we would want to be treated.

"Do unto others as you would have them do unto you"  (Luke 6:31 NIV)

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Hours of Operation


Primary Location


8:30 am-4:30 pm


8:30 am-4:30 pm


8:30 am-4:30 pm


8:30 am-4:30 pm


8:30 am-3:00 pm