Meet the Team

Dentists and Dental Specialists:
you can bring your own patients to our facility and perform dental procedures on your patients under sedation. MDSD&SC can also provide our affiliated specialists to work with you as a team.


Patients can set up appointments directly to have comprehensive dental work done utilized our affiliated General, Cosmetic, Prosthodontic, Oral Surgery, Endodontics, Periodontics, Orthodontics, Pediatric Dental Care, and Family Dentists, all performed under sedation.

Meet Our Dentists, Oral Surgeons & Endodontists

Dr. EJ Stringer, DMD

Dentist in Frederick, MD

Dr. Stringer - Dentist Frederick MD

Dr. Stringer finished her undergraduate work at Penn State University, where she not only made dean’s lists each semester but also received numerous awards,  given to the top student of the class.  While attending Penn State she was invited to join the National Health Pre-professional Honor Society, Alpha Epsilon Delta.  She received her D.M.D. (Doctor of Medical Dentistry) from the University Of Pittsburgh’s School Of Dental Medicine, where she graduated with an outstanding academic record.  She attended Pitt with an academic scholarship, awarded only to a highly select group of students, showing outstanding academic achievement.   Dr. Stringer has focused training in sedation dentistry, oral surgery, and AEGD (Advanced Education in General Dentistry). 

Frederick Dental Team

On a personal note, she and her husband live in The Villages of Urbana, with Koda their golden retriever.  Dr. Stringer enjoys hiking, gardening, fishing, playing the piano, skiing, traveling and playing fetch with her dog.

Dr. EJ’s is a sponsor of The United Way, YMCA, SPCA, UNICEF, Goodwill, and NPR.

Dr. Brian Chang

Oral Surgeon in Frederick, MD
PearlFection Dentistry


Dr. Brian Chang is a native of the Washington Metropolitan area, growing up in Silver Spring, Maryland. He then earned his undergraduate degree at the University of Virginia in Biology and Economics.

Dr. Chang earned his dental degree from the University of Pennsylvania through the Health Professional Scholarship Program from the U.S. Army. He decided to pursue additional training and completed his residency in Oral and Maxillofacial Surgery at Walter Reed Army Medical Center and Bethesda Naval Medical Center. He spent the following four years as the Chief of Oral and Maxillofacial Surgery at Fort Polk, Louisiana, treating our soldiers and other service members.

Dr. Chang decided to come back to the Frederick, Maryland area with the surgical knowledge and expertise gained from his training in the army.

Dr Brian Chang - oral surgeon Frederick MD - and family in pumpkin patch

He is active in a variety of professional associations and has been published in professional journals.

Dr. Chang is board certified by the American Board of Oral and Maxillofacial Surgery.

Dr.  Stephen Tigani

Orthodontist in Frederick, MD

Dr. Tigani - Dentist Frederick

Dr. Tigani is committed to providing his patients with the best possible orthodontic care in the Washington area. He has worked in orthodontics for over fifteen years and believes in treating each and every patient with the individual care and attention they deserve. Dr. Tigani is passionate about his profession and enjoys combining the art and science of orthodontics. He provides his patients with the latest technology and advances in orthodontics while maintaining a personal and caring relationship with every adult, teen or child. Dr. Tigani believes every patient should have a healthy, happy smile that lasts a lifetime.

Dr. Tigani received his Bachelor of Science degree from Georgetown University in 1988 where he majored in Psychology and minored in Biology. He then received his Doctor of Dental Surgery degree from the University of Maryland, Baltimore College of Dental Surgery, Dental School in 1992, after which, he worked with his father, brother, sister and brother-in-law as a general dentist while pursuing his orthodontic degree. Dr. Tigani then completed a two-year orthodontic residency program at Columbia University in 1995.

Dr. Tigani is a native Washingtonian who is involved at both the professional and community levels. He is a member of the American Association of Orthodontists, the World Federation of Orthodontists, the American Dental Association, the District of Columbia Dental Society, and a fellow of the International College of Dentists (ICD) and the American College of Dentists (ACD). The ICD is an honorary international organization that recognizes dentists for outstanding and meritorious service to the profession of dentistry and to the community. The ACD's members exemplify excellence through outstanding leadership and exceptional contributions to dentistry and society. He is a past President of the District of Columbia Dental Society, a component of the ADA that helps in the further advancement of the dental profession while being an advocate for the community and dentistry as a whole. Dr. Tigani is the past Chairman for the D.C. Dental Society's "Give Kids a Smile Program," an annual event providing oral health care to low-income families in the Washington, DC area. He currently represents the District of Columbia Dental Society as a delegate to the American Dental Association and also serves on the ADA Council on Membership.

Dr. Tigani has been involved with his community civic associations, coaches soccer and basketball for the past 20 years, and serves on numerous boards and councils. He is currently a delegate to the American Dental Association. He has been married for 27 years and has four children who attend various colleges and graduate schools.

Dr. Tammira Badakhshan, DDS, MS

Dentist in Frederick, MD
PearlFection Dentistry

Dr. Badakhshan - Frederick MD Dentist

Dr. Tammira Badakhshan is a Maryland native. She was born and raised in Gaithersburg, Maryland. She completed her undergraduate studies at the University of Maryland, College Park with a Bachelor of Science in Biology. She then attended the University Of Maryland Dental School in Baltimore where she earned her Doctor of Dental Surgery degree. While in dental school, Dr. Badakhshan gained ample experience in all aspects of dentistry. After dental school, she moved back to her hometown and is now privileged to be serving the dental health care needs of her community.

As a member of the Maryland State Dental Association, American Dental Association, and Academy of General Dentistry, Dr. Badakhshan is one of the most well-respected young dentists in Maryland. She is enhancing her skills with continuing education courses each year.  Dr. Badakhshan believes in providing the highest quality of dental care, in a friendly and comfortable environment, while maintaining lasting relationships with each individual.

Outside of work, Dr. Badakhshan enjoys spending time with family and friends and loves traveling to new places. She is fluent in Farsi.

Dr. Amos Chi

Prosthodontist in Frederick, MD
PearlFection Dentistry

Dr. Chi - Frederick MD Dentist

Dr. Chi is a Lieutenant Colonel in the United States Army. Dr. Chi graduated from the University of Virginia with a bachelor degree in Biochemistry. He was awarded the Doctor of Dental Surgery degree from the University of Maryland in 2005. He completed a three-year residency program specializing in prosthodontics at the U.S. Army Postgraduate Dental School in Augusta, Georgia in 2008, and a Master of Sciences in Oral Biology from Dental College of Georgia at Augusta University, Augusta, GA. His thesis entitled ‘Resistance to abrasion of extrinsic porcelain esthetic characterization techniques.’ was published, in July 2017, in the Army Medical Department Journal. Dr. Chi has to his credit a fellowship in Oral Oncology and Maxillofacial Prosthodontics from The University of Texas, M.D. Anderson Cancer Center, Houston, Texas in 2018 where his clinical work titled ‘Prosthodontic treatment of a patient with Ewing sarcoma of the left maxillary sinus: A clinical report’ was accepted for publication in 2018, in the Journal of Prosthetic Dentistry.

Dr. Chi has been conferred numerous awards. In 2018, he was conferred the Maxillofacial Foundation Award by the American Academy of Maxillofacial Prosthodontics. In July 2016, Dr. Chi was awarded Meritorious Service Medal by the United States Army. Dr. Chi was as an ‘Invited Speaker’ at International Congress of Oral Implantologists, Korea Section and Seoul International *Dental* Exhibition & Scientific Congress on the topic of ‘Zirconia Restorations’.

Dr. Chi has multiple scientific papers published in both national and international journals as well as poster discussions at national conferences. Dr. Chi presented two abstracts entitled ‘Prosthodontic treatment of a patient with Ewing sarcoma of the left maxillary sinus: A clinical report’ and ‘The effects of zinc on radiation-induced dysgeusia: A meta-analysis’ during American Academy of Maxillofacial Prosthodontics and American College of Prosthodontists meetings in 2018.

Dr. Chi is a Diplomate of the American Board of Prosthodontics, a Fellow of the American College of Prosthodontists, and an Associate Fellow of the American Academy of Maxillofacial Prosthetics.

Dr. Nikta Pashai

Dentist in Frederick, MD
PearlFection Dentistry

Dr. Pashai - Dentist Frederick MD

Dr. Nikta Pashai is a general dentist that is devoted to giving quality patient care and building long term relationships with each of her patients. She is committed to providing healthy smiles through carefully designed and customized treatment plans. As a member of the American Dental Association, Maryland State Dental Association, and Academy of General Dentistry, she is dedicated to continued education and staying current with new advances in the dental field.

Dr. Nikta Pashai was born and raised in Ellicott City, Maryland. She attended University of Maryland, College Park, graduating with a Bachelor of Science degree in Biology. She earned her dental degree from University of Maryland School of Dentistry in Baltimore. While in dental school, Dr. Pashai enjoyed giving back to the community by participating in Mid- Maryland Mission of Mercy events and providing dental screenings for Special Olympics participants..

After completing her dental degree, Dr. Pashai went on to complete an Advanced Education in General Dentistry Residency program at University of Maryland School of Dentistry. During her residency, Dr. Pashai was able to expand on her current skills by managing complex comprehensive cases and gaining proficiency with cutting edge technology.

In her spare time, she enjoys spending time with family and friends, traveling and outdoor activities.

Dr. Scott Pasieta


Dr.Blake Rosacker received his Bachelor of Arts degree in Molecular, Cellular, and Developmental Biology in 2006 from the University of Colorado. He received the Health Sciences Collegiate Program Scholarship (HSCP) in 2008, and went on to graduate from Case Western School of Dental Medicine with his Doctorate of Medical Dentistry degree in 2010. He continued his education at the Naval Postgraduate Dental School earning a Masters degree in Oral Biology and receiving a certificate of specialization in Comprehensive Dentistry. He attained his board certification from the American Board of General Dentistry in 2013.

In 2015, he reported to Marine Corps Recruiting Depot–Dental Clinic, Parris Island, SC. In his initial year, CDR Rosacker served as assistant department head for general dentistry where he led a 70 member team in the delivery of dental care to a population of more than 18,000 Marine Recruits and coordinated the daily schedules of 41 dental providers. During that time, he developed and implemented the new team dentistry concept which reduced average dental treatment days for recruits by 50%. For his efforts he was recognized by the Deputy Surgeon General. Subsequently, CDR Rosacker took over as Credentialing Tour Coordinator, mentoring 11 new dental officers in complex patient care. From 2017 to 2021 CDR Rosacker served as general dentistry department head for two years each for both the Capodichino Flightline Dental Clinic and subsequently the US Naval Hospital in Naples Italy. As department head for the Flight Line clinic, he led a 13 member team in delivering dental care and maintaining readiness for 1,600personnel. As department head for the Naval Hospital, he increased patient access to care by 300% while leading a 20 member team in the delivery of care to 3,000 beneficiaries. During this period, he also served as the dental liaison for naval assets in Poland and Romania, resulting in a 50 percent increase in readiness for forward deployed forces. In 2021, he reported to Walter Reed National Military medical center where he served as the Program Director for the General Practice Residency Program and trained six new dental officers in complex hospital based dental care each year. In the summer of 2023 CDR Rosacker reported to the Naval Post Graduate Dental school where he currently serves as the Program Director for the two-year Comprehensive Dentistry Residency Program. His program trains 16 residents in multi-disciplinary specialty care for forward deployed units and confers a Masters Degree in Oral Biology.

Throughout all his successes, CDR Rosacker met his wife while traveling abroad in the Pacific Rim on Semester at Sea during his undergraduate years where they visited 9 different countries. He has been married for seventeen years and they have 4 children together


Meet Our Dental Hygienists, Dental Assistants & Staff



Graduated from Frederick High School. Took advertising classes at Career and technology center. Studied Psychology and business at Frederick Community College. Native to Frederick but frequently loves to travel and loves spending time with her family, friends, and dog.


Molly - Office Administrator

Born and raised in Middletown, Maryland. graduated from Middletown High School and graduated Towson University in May 2016 with her degree in Psychology. Plans to attend hygiene school within the next few years. Enjoys fishing, family game nights and hiking.


Susan - Dental Assistant

Susan has worked as a dental assistant for Dr. Mullen for 14 years. Her father is a retired DDS and sparked her interest in the dental field at a young age. Susan finds it especially enjoyable getting to know the patients and helping them feel comfortable and relaxed through their dental experience. She loves the outdoors, playing tennis, and spending time with her family. Susan has a husband of 30 years, six kids, and five grandkids.

Jessica - Orthodontic and Dental Assistant

As having my radiology certificate and being an orthodontic assistant, I enjoy helping patients achieve the smile they want. When I'm not at work, I love spending time with my kids.


Danielle - Dental Hygienist

Danielle is a native of Virginia Beach, VA. She graduated Cum Laude with a B.S. in Dental Hygiene from Virginia Commonwealth University, School of Dentistry in Richmond, VA and received a B.S. in Marketing at Old Dominion University in Norfolk, VA. Danielle fell in love with dentistry by volunteering at an American Red Cross dental clinic and therefore pursued a career as a dental hygienist. She strives to make each patient’s appointment a positive experience while focusing on oral and overall health. In her free time, Danielle enjoys reading, being outside, cooking, and spending time with her family, friends, and dog.


Mikaela Smith

Mikaela graduated from Hagerstown Community College with an A.A.S. in Dental Hygiene. She was given the award for Outstanding Student in Dental Hygiene. She is also licensed to administer local anesthesia. Outside of work she enjoys cooking, making crafts, and spending time with her friends and family.



Shabnam is native to Maryland and graduated from the Community College of Baltimore County Dental Hygiene Program with an A.A.S and is licensed to administer local anesthesia. Outside of the Dental field she is a Licensed Massage Therapist and enjoys yoga, dance, traveling and spending time with her son.

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