Sierra joined Dr. Leppo and the Columbia Dental Center team in 2017 as the Treatment Coordinator. She has been in the dental field since 2013, where she entered dentistry as a Certified Dental Assistant (C.D.A). She soon found her fit in coordinating patient care. Sierra says, "I truly enjoy helping our patients navigate the dental world and making the office feel more like home to everyone." She looks forward to coming into work each day knowing she'll be working with a tremendous team, and that we will be able to help patients attain the healthy and beautiful smiles they deserve. In her spare time, she enjoys being with her husband, Brian, and two children. She spends most of her time attending various sporting events in St. Louis, and supports our local teams in and around Millstadt where they now live.




When asked what Tami most likes about her position at Columbia Dental Center, she quickly responds that she “LOVES educating patients especially on care of braces using flossers.” Educating is something she has been doing for 17 years in practice here along with dental assisting, coordinating hygiene and polishing teeth. Tami ensures appointments run smoothly from the time she takes needed x-rays to charting and re-appointing for future visits. She works on operatory set-up, maintains sterilization of instruments and does maintenance throughout the office. Tami has advanced CPR training as well as training in Sleep Apnea. Outside of the office, Tami can be seen riding in her vintage BMW where she says “convertible hair-don’t care!” As a mom and grandma spending time with family (this includes time spent with her tea- cup yorkie ) is very important to her. When she sits and watches her favorite movie, she is watching “The Notebook”. You may catch Tami eating often at the Cheesecake Factory or in line at Starbucks where she is ordering a white, mocha-latte, no-whip, skim…oh, and a shot of ESPRESSO, please!





Karen is our veteran at Columbia Dental Center - practicing almost 20 years. Her dental career began back in the 80’s when she worked chairside as a dental assistant until she returned to college and graduated in the 90’s with her hygiene degree. Over the years, she has worked with prominent dental companies in product development, sat on dental advisory panels, tested and evaluated products as a clinical researcher, past national lecturer, and had been a feature and monthly author for RDH Magazine as a columnist for five years. Her proudest accomplishment was being one of eight chosen nationally as a winner of the prestigious “Award of Distinction”, in dental hygiene.

Karen is passionate about her patients and enjoys how her younger patients have “grown up” under her care - so don’t be surprised if she opens up a fun picture when you were five years old and puts it on her computer screen for you to see and enjoy a light-hearted laugh! Karen’s most famous patient was a home-run hitting Cardinal from the late 90’s.

Now, she has her own baseball player, her son. He attends Vanderbilt University in Nashville, as a pitcher. Karen is “from home” in Waterloo…a term used by locals who have lived in the area their entire life and have family here. She is a grandma of four, whom she adores! She has authored a book (found on Amazon), and is a part of local non-profit group “Project Skipper”, which educates kids about the dangers of ice-covered water. She holds a black belt in Shorin-ryu karate, plays violin and abstract paints for artsy-relaxation.





Fresh in the dental field, Ashley has been practicing since 2015 as a Registered Dental Hygienist. As a hygienist, her favorite undertaking is working with a patient who is insecure about their smile with a goal to give them back confidence through her care. Ashley’s favorite color is purple which is fitting because purple is the color associated with dental hygiene.

She lives in Columbia with her volunteer firefighting husband, Kyle, and wants to soon start a family. She already has the family pets because she is a dog-lover and has two Labs. When Ashley wants excitement, she watches Blues hockey and enjoys float trips and camping. When she wants to relax, she says she is a page-turner and enjoys reading or listening to audio books.

Ashley says what she enjoys about our dental office is the down to earth atmosphere and the exceptional care she's able to provide to our patients.





In 2013, Casey joined our practice as a lead chairside assistant. In addition to assisting, she sterilizes and maintains dental equipment, tools, and treatment areas, and assists in keeping the office clean and tidy. She is CPR-certified and has training in Sleep Apnea.

Casey enjoys expanding her education especially with new, innovative technology that makes our patients feel comfortable while having treatment. She relates well to patients of all ages and enjoys meeting new faces and getting to learn about them as well as their families. Casey has a tender touch and uses her skills to educate patients about needed treatment before, during and post-operatively.

Away from work, she loves spending time with her husband, Jeremy, and her fur baby, Sam. She enjoys shopping and baking desserts (her cookies are amazing!) but her most favorite pastime of all is going four-wheeler riding on the weekend with her family and friends!





Wanda has over 28 years of experience in the dental field and has been in our office since February of 2016. She is knowledgeable about many dental procedures and enjoys educating patients, answering questions, and calming their fears . Wanda is Nitrous Oxide and sedation certified. She strives to do her best to make patients feel comfortable which is a great reward for her. Patients experience this calm feeling and enjoy our office's soothing environment during treatment.

Wanda delights in changing smiles and changing lives through dentistry. She is trained in correcting smiles through Invisalign, implant treatment, and CEREC digital dental crown technology. Through those skills, she is a patient advocate and enjoys the challenge of creating financial plans to help patients reach a smile goal. She builds patient relationships with her bubbly, positive personality and radiant smile.

Wanda loves to travel, dine out, and spend time outdoors. She values quality time with her husband, Gary, their three children (and a future son-in-law), and furry baby, Koda. Family, friends, baking, reading and camping are her treasures.





Marilyn has been in the dental field since 2002. She is the primary liaison for patients regarding treatment scheduling, insurance filing, and financials. She's the glue that keeps the office together and does everything with a [perfect] smile. She and her husband Jim have three (adult) children living in IL and CA, and two little one's who love her unconditionally and call her "grandma". When she's not busy managing an office she enjoys living her active lifestyle and traveling! Say hello next time visit - you know she'll smile back at you and ask how your day has been...and when we can make your next appointment.





Walk in the office front door and Mary will be there at the front desk to greet you. She started working in our office in 2011 on a temporary basis, then returned in October 2014 to a full time position. Mary handles inbound calls, mail, and checks patients in and out during appointments along with scheduling any follow up appointments needed for treatment. She checks patient’s insurance benefits, assists with flexible spending accounts and coordinates insurance benefits. Additionally, she helps manage our office website and Facebook page. Mary replies to emails and handles correspondence.

Out of the office, her family is her priority! She spends a lot of time with her family, including her husband, Jim, sons, Zach and Logan, and her daughter, Lauren; Mary also has three rescue dogs, Albert, Drake and Jaxon; a cat, Tippy; goldfish and three tiny turtles. Mary is a local “from home” Waterloo girl, but her ultimate “happy place” is being on the water on her pontoon boat, swimming, and soaking up the sun (don’t even ask her how she tolerates wintertime, LOL). Four-wheeler riding, gardening, reading and working out are a few activities she takes pleasure doing.





Britani is one of our Registered Dental Hygienists at Columbia Dental Center and joined our team in 2011. While in her hygiene program, she received the “Colgate Oral Health STAR” award. This award is given to only one hygienist in the graduating class who demonstrates excellent patient motivation skills. Britani is a lifelong learner and has certification in Laser Periodontal Therapy and local anesthesia.

She currently lives in Troy, Illinois with her husband and daughter. Her family activities include going to the local park with her daughter to blow bubbles, fly kites, and feed bread to the ducks.

When Britani finds the time to relax, she enjoys reading books from a variety of different genres and always welcomes a good book suggestion. Some of her favorite past book reads have been at her patient's recommendations, (especially the Outlander series, which is historical fiction). You will find that when you have an appointment with Britani that your experience will be fun and comfortable because of her warm and compassionate personality.