Meet Our Dental Team

Our Dentists

Our Dental Team

Meet Your Irving Dentists

Dr. Kent Smith

B. Kent Smith - DDS, Diplomate American Board Dental Sleep Medicine (not an ADA recognized specialty) - married to Diana since 1982, he is the father of 4 beautiful girls, who will be allowed to wed after his death. Much of his spare time is spent supplying continuing education information for professionals with his web site, and opportunities for speakers with

Frequently published, Dr. Smith is often asked to speak on topics such as sleep apnea, short term orthodontics, web site development and inter-office communication. An active member of the International Association for Comprehensive Aesthetics (Lamplighter Award for 2008), American Academy of Dental Practice Administration, the American Academy of Craniofacial Pain and the American Academy for Dental Sleep Medicine, he is also on the Advisory Board for Sleep Healers, and the co-founder of the Dental Organization for Sleep Apnea.

In 2007, he was asked to create a program and was then appointed as the course director/instructor for Sleep Breathing Disorders at the Las Vegas Institute for Advanced Dental Studies. He taught workshops/seminars there for several years, until he left to teach at other venues. In 2009, he was asked to be a clinical instructor for Six Month Smiles, which is a type of Short Term Orthodontics using clear braces.

He and the family enjoy scuba diving together, and are all rabid Dallas Maverick fans. An Eagle Scout, he annually works with his brother, a neuro-ophthalmologist and fellow Eagle Scout, in providing care to the less fortunate in and around Tampico, Mexico.

Dr. Smith established what is now 21st Century Dental in 1985, and is excited to be practicing in this new era of dentistry. He is passionate about creating beautiful and functional smiles for his patients, and to that end, he stays on the leading edge of research and development of new materials and procedures. Truthfully, he's the best darn dentist in the world. In his spare time, he writes bios for web sites. See his full CV here. See his speaking schedule here.

Dr. Jeff Roy

"Family first", Married to Alicia in June of 1996 - incredibly proud of her heart of service and compassion through ALARM, and other charitable avenues locally, and globally. Hunter enjoys both gaming & playing basketball. A voracious reader of fiction, he also has a great sense of and appreciation for humor. Hannah is fiery & passionate, bursting at the seams with love, spirit and entertainment, and the girl loves dogs!  She is a cheerleader at school and a drummer in my garage.  They both love social media (insert Dad’s eye roll here).

Dr. Roy was awarded the prestigious Fellowship status in the Academy of General Dentistry in July of 2004. Dr. Roy was also honored as the 2007 Dentist of the Year of the Dallas Academy of General Dentistry by his peers, and represented Dallas at the Texas AGD Annual Meeting. He was selected as a Texas Monthly Super Dentist every year by his peers since 2008 based on the following criteria. He feels especially honored to be chosen by his colleagues, and wants to humbly thank them for the peer recognition (yet must assure the web surfing world that he's not superior to any Texas Dentist)!

An active, sought after leader serving or logging past service on multiple boards and leadership committees within the dental profession, he is Past President and Board Director of the Dallas Academy of General Dentistry, a National Delegate, and recent Board Director for the Texas Academy of General Dentistry. Dr. Roy most enjoyed time as Editor for the TexasGP, the official publication for the Texas AGD, although resigning to focus on the family.

In his spare time, he fancies any manner of family fun or time experiencing the great outdoors, and as time permits internet dental forums, Twitter, and either playing or following most local sports activities, especially those of his children.

Dr. Ashley Bristow

Dr. Bristow is a Texas girl to the core. Growing up in Mesquite, she traveled across Texas to study at Baylor University for her undergraduate degree and to Houston at the UT School of Dentistry to for her doctor of dental surgery degree. She now lives in Irving, excited to be near her Mesquite family and her 21st Century Dental family. Dr. Bristow is an active member of the Golden Retriever Rescue of North Texas and serves as a foster home for pups in need. She did become a "foster failure" and is now a forever home for her sweet Lucy Lu and can be heard talking about her anywhere in the office. She and Lucy Lu are volunteers at local hospice centers as Paw Pals, visiting with the patients there, spreading the golden retriever love!

Dr. Bristow also volunteers at the North Dallas Shared Ministries dental clinic where she provides thousands of dollars in free dental care to those unable to afford the care otherwise. She has been active in volunteer organizations such as Big Brothers Big Sisters of America and volunteers with international dental mission trips. In 2012 she led the fundraiser for 21st Century Dental to raise over $2,000 for the Special Olympics Texas and celebrated with the organization by rappelling down the side of a 15 story building. When not volunteering you can find her running around Home Depot with Lucy Lu (yes they allow dogs!) getting materials for her latest DIY project or in the library ignoring the "new fad" of electronic books. Dr. Bristow is a member of the Texas Dental Association, the American Dental Association, the Dallas County Dental Society, and the Texas Association of Women Dentists. She is also a Crown Council finalist for the 2013 "Young Dentist of the Year" award.

Dr. Andrew Barnett

Dr. Andrew Barnett, a native English and Spanish speaker, was born in San Juan, Puerto Rico. Through his father’s job at Ford Motor Company, he got to live around the world but always called Detroit his home. He attended the University of Michigan and earned his Bachelor of Science degree in Biopsychology and Cognitive Sciences. To pursue his passion in dentistry, he attended the University of Pittsburgh and received his Doctorate in Dental Medicine. Choosing to specialize, he returned to the University of Michigan and completed his Certificate in Periodontics. As a Michigan Board Certified Periodontist, he is experienced in surgical services including implants, soft tissue grafts, bone augmentation, extraction of impacted teeth, and resective and regenerative therapies for the treatment of periodontal disease.

Having loved living in Dallas before, Dr. Barnett has decided to make it his new home. He moved here with his girlfriend, Mariya, who is currently enrolled in a general dentistry residency at Baylor. Together, they enjoy rooting for their Wolverines and exploring everything Dallas has to offer.


Meet the Dental Team

Jill Cruson- Registered Dental Assistant

In her 22nd year!... married for 17 years to Tommy, mom to Justin Blake, and a "don't-forget-me-mommy!" to big sis Aubree; She enjoys country music, country videos and country cooking, so we caynt quite figger how she wined up hangin with us city folk. Anyhow, once we lassoed her, she's been a harder worker than Buford.


Kristi "Bailey" Horn -Schedule Coordinator

Kristi (actually, she now goes by Bailey so she is not confused with Christy, Kris Kringle or Crysanthemum) came to us in 2000 with plenty of experience. Bailey will be the first smiling face you see when you come in to see us, and we put her there because her big smile will tell you she is genuinely glad to see you walk in that door! A former chairside assistant for Dr. Roy, she is very knowledgeable about clinical issues, so if you break a tooth, you can certainly cry on her shoulder when you call.

Helen Brewer - Registered Dental Hygienist

She brings a wealth of experience and maturity to our hygiene team all packaged in a sweet spirit and warm personality! Not to mention her smile, her teeth are perfect; we're so jealous!

When not detoxifying gingival sulci (fancy dental speak for showing gum bacteria who's boss), she spends time being a sports agent and manager for Dimitrian, her wonderful son, supervising the logistics as he shuffles to and from junior high football games and school. Proof of her astute mothering skills, she practices many of the technological advances that Robert Deniro utilized while watching his future son-n-law, Greg Focker, in the movie Meet the Parents. Born and reared in Odessa, it's no wonder her son Dimitrian is a "natural" football Friday Night Lights, it's in his blood!

When not entertaining, cooking, or hanging out by the pool, she does her fair share of "hard time" volunteering with the PTA, locally. A single mom, act fast fellas; she even likes watching football and fishing at her parents' lake house!!!!!

Cameron Caywood - Registered Dental Hygienist

Coming to 21st Century Dental in 2003 - When we hired Cameron, we were not really looking to add a 4th hygienist, but her magnetic and energizing personality left us no choice. When you see her smile, you will understand. She and husband Tracy enjoy sports and competition, illustrated by the fact they own their own bowling balls. You can find her after hours using our hallway for practice. They have gradually migrated to the links, however, because Cameron can drive her cart and not worry about getting pulled over.

Growing up on Lake Bridgeport, she has been skiing her whole life, and enjoys liberally-defined water sports like fishing and snow skiing. Other interests include softball, putt-putt and spoiling her weenie dogs, Georgia and Daisy...with food scraps from the table.

Cameron and Tracy have two wonderfully engaging children, Madeline and Samuel. As we have no photos to share here, we must assume a rather lackluster and ambivalent attitude towards her children, but rest assured, she cares for her patients, so come meet Cameron soon...and if you see any photos of the kids...sneak one to us!

April Casanova - Registered Dental Assistant, Sleep Department

(AKA Dr. Smith's chairside sleep assistant)- a sweet and charming family member at 21st Century Dental...born in New York, raised in Orlando, she somehow couldn't shake the curse of being a New York Yankees fan#!%..well, she really just likes how Derek Jeter looks in his pins and stripes.

She has a special interest working with Dr. Smith and his snoring and sleep apnea patients, but for some reason will not let us call her the Sleep Expert. She prefers the acronym of S.A.C. (you'll have to ask her)

The light of her life is her precious daughter Elizabeth, born in 2003. Do your best to make her smile...your payoff will be a glimpse at the cutest dimples.


Lisa Barrera - Operations Manager

Joined us in 2005, but it feels like she has been a part of the team forever. Born in California, but daughter of a Marine, she has moved so many times she started taking the house numbers with her so she wouldn't have to learn a new address. A college cheerleader, she attracted husband Nick, who was, and still is, playing baseball. Very family-oriented, she spends a great deal of time with her extended families, usually watching baseball and softball games with daughters Gabi and Alyssa. If we end up with ponytails, a 21st Century Dental mascot and the tendency to pull out a megaphone and yell out D-E-C-A-Y, you will know who to blame.


Natalie Donofrio - Registered Dental Assistant

Where do we start here? Girl grows up in Dallas, moves to Phoenix, then moves back home to Big D thinking she's a Phoenix Suns fan, God forbid. How did that little nugget sneak past the Docs in the interviewing process?

Dancing with the Stars is a way of life in the Castillo household, and there's no need to wait until Saturday Night to catch the fever! An accomplished assistant, Dr. Roy is elated to have found her. She's steady, calm, and more than able to handle the gale force winds of life and practice! Now back to those sports alliances?

Lil Ortega - Registered Dental Hygienist

Born in Southern Brazil, meet Maria Leopoldina Ortega... um, yeah, so we just call her "Lil". She's one of the smiling faces in our office on the dental hygiene team, and just your average Brazilian (thought that was a big number, not a country, but always willing to learn) girl in the US working on the thing she loves most - teeth (whatever). Dr. Roy met her on a mission trip in Mexico, bragged about her to Dr. Smith and our office manager for two years, and "the rest is history" as they say. She is raising 2 lovely children, a red-headed firecracker named Joseph and a sweet princess named Claire Marie. They are blessed to have two elder dogs named Bernard and Socks. Lil loves to travel, be with her family, and save dogs. She is a consummate professional in all that she does, save for "talking sports". Lil has a BIG heart, and I'd say it's "one in a Brazilian!" (oh yeah, country not number) She loves to help people and can't drive by a stray dog w/o picking it up. They have a third dog named "Girlie" (guessing it's a male) because they couldn't find her owner. In Texas, we say folks like Lil are "sweeter than Molasses", and we could tell you a Brazilian (don't try and stop me) ways that's true for her.


Felicia Calloway - Treatment Coordinator

Felicia came to us in 2011 from the retiring state of Florida, because, frankly, she wasn't ready to retire. No one retires in Texas. Actually, horseback riding is what brung her, she took a plane from Florida (for the fifth graders reading this), but she does love horses. And Charlie Sheen.

Seen with Orlando Jones here, Felicia has gone all Sheen on us, when last we heard her exclaim "I'm not bi-polar, I'm bi-winning. I win here and I win there." Give it a rest, Felicia - that's just a cardboard cutout of Orlando.

She was actually born in Wichita, KS, but since no one has actually LIVED in Kansas as far as we know, we just say she's from "up north". She has worked in the dental field as a chairside assistant for 16 years (started when she was 4), so she can answer most any question you ask her. In fact, as a production assistant for a fashion trade show, she can also give you some clues on what to wear to a dental office. (Hint - dress for comfort)

Truthfully, we LOVE Felicia's Broadway smile. If I had a dime for every time I saw her without a smile, I still couldn't buy a stick of gum. And yes, I would still be saying this if she DIDN'T have a doberman named Napoleon.

Jason Colbert - Registered Dental Assistant

Jason joined 21st Century Dental in 2011 after he interned here for 3 months. We could not bear to lose him to another office, so we quickly created an extra position. He is now largely responsible for juxtaposing underwater fragmented kelp fronds with basil-laced fungi (genus Lardobacillus) in an effort to find the elusive cure for dental fear. We couldn't have picked a better man for the job.

In his spare time, he brings a frenetic, abundant and resourceful amount of energy that never seems to run low. Born in Waco (that's in Texas, for our northern folk), he loves all Dallas sports (the Rangers are actually in Arlington...and well, so are the Cowboys, but who cares about geography?). Naturally, with his love of sports comes a love of culture - music, people and art - but especially the people part. The youngest of 3 boys, he also has 3 children - Dayton, Jordan and Sati.

If you notice someone with a big grin and a passion for being the best, you must have seen Jason. If you see him in the grass outside scavenging fungus, just leave him alone. He's on a mission!

Jenna Williams - Registered Dental Hygienist

Like any good Aggie, Jenna teamed with another Aggie in marriage, but Fred (not his real name) spent 8 years in military intelligence, so any further information about their relationship, and he would have to.......well, we can at least say they spent the first year of their marriage in Iraq, which is not what you see in the background to the right.

They have an athlete for a son, whose court presence reminds us of Roddy Beaubois. I'm just sayin....In fact, they are so enamored of his talents that they have done some genetic engineering (remember "Fred"?), and are having a second son in a few short weeks from this writing.

They love to snow ski, water ski, hike, kayak....just about anything outside with temperatures that run south of what they experienced in Iraq. Come meet the lovely, talented...and very pregnant Jenna!


Lucy Cornejo - Treatment Coordinator

We never knew that when fabulous collided with the biggest smile on the planet we would get a Lucy out of it. She hit the ground running when she joined our office in 2014 as Dr. Bristow’s treatment coordinator. Our “girly-girl” up front, she loves online shopping, working out, and sporting lipstick shades that pop. She’s also got a bit of a little kid side… No she doesn’t have any, but she likes eating things like fruit roll ups and Gushers when no one is looking. Yet she has no cavities. Crazy! She loves the color black and rocks it every day in the office as she greets and checks out all of our amazing patients. We love hearing that sweet voice ring through the halls, she is always on a mission to make the people around her happy and cheerful. Come by or call the office and see for yourself!


Michelle Carpenter Herrera - Registered Dental Hygienist

Dr. Roy's chairside assistant from 2000-2006 ish (training ground for all of the great ones), Michelle stepped away for a list of personal reasons: A) "dental sabbatical" (friggin' moved to South Texas on us), B) to reproduce (box checked, twice), C) to get educated in a different arena of the dental field. She actually met her hubby in this office which was a really sweet story - until he asked her to move away FROM us. Fast forward a few years, she came back!! Starring in a leading role practicing on the other end of the 21st Century Dental building ("Wonder twin powers, form of a dental hygienist!"), Michelle brings many talents but to mention a few: 1989 power lifting champion (internet searches could not confirm), enjoys shot put (we're thinking track & field, can't rule out alcohol); Master, 3rd chair, cow bell player (definitely made up, but can never have too much cowbell); loves to put up glass shelves in dental op's in the direct path of patients (there's a story here, trust us); & Karaoke Queen. There is a whole lotta quality and personality in Michelle!!!!


Diane Nguyen - Registered Dental Hygienist

Meet one of our amazing hygienists, Diane! She’s a laid back type of girl who loves to travel, hiking, crafting, and trying new places to eat. She may not sing to you during your appointment, but know there’s hidden talent there. She just needs a microphone and a mediocre speaker to sing the greatest hits in karaoke. When she’s not on tour behind the scenes, she is cleaning teeth and getting our patients healthy one mouth at a time. She is a graduate of the University of Texas at Arlington and received her degree in dental hygiene from Tarrant County College. Her parents moved here from Vietnam in 1982 and Diane was born and raised in the US. She speaks Vietnamese which adds another language spoken to the long list of spoken languages at 21st Century Dental & Sleep Center. We know you’ll love Diane as much as we do, come visit her today!


Lissette Gurrola - Registered Dental Assistant

Lissette is our rock star hygiene department assistant extraordinaire. When she's not cheering on her favorite team, the Texas Rangers of course, you can find her in the office helping behind the scenes. She has a "happy to do it" attitude that shines with her teammates and patients alike. She has a Maltese named Charles who she loves dearly, and we think, may be where she gets that adorable spirit from. Lissette is the picture of a hard worker and when not keeping a tight ship in office she is school studying to one day become a hygienist herself! Committed to excellent patient care and positive practice culture Lissette shines in everything that she does. She claims she loves her team, but we think her team and her patients love her more!


Itzel Becerril - Registered Dental Assistant

When she's not putting off procrastination, she spends time learning how to boil water in order to submerse edible things for her family to eat (i.e. cooking lessons). The baby of her family & the pride of Duncanville, she stuck a foot in the waters of nursing and quickly decided that dentistry is where she's meant to be!!! Walked into this place fearlessly, never hesitates to help anywhere for anyone, and both quietly & peacefully overflows with skill and sweetness as she goes about her day. She's a highly skilled dental assistant! Married with a son, don't let her gentle nature and spirit full you…she's a machine in the world of Call of Duty! She loves her family at both work and home, and we love her! Meet Itzel!!!


Sophie Bach - Administrative Assistant

Sophie is the first smiling face you will see when walking in the door to our office. She is in school now studying biology with the aim to get into the field of neuroscience as her education continues. Between being at the office full time and taking classes at night this girl still finds time to stay healthy working out and spend time yelling at the TV during football season. OK, maybe not yell, but she would definitely use her sweet nature to politely tell those referees when a play is called incorrectly. She has a cat that is like her child and has a joy for life that is amazing. Her enthusiasm and positivity are contagious and we are so excited to have her represent the “face” of the practice as she greets everyone as they check in!


Jordan Austin - Hygiene Coordinator

Jordan is our superstar hygiene coordinator! Making your clean dreams come true we are lucky to have her in our neck of the woods. She grew up in Tyler but couldn’t keep her mind off of the big city (and 21st Century Dental & Sleep Center). So she moved to Dallas with a dream… and Bambi and Duchess. No, not the cartoon or aristocracy, her two cats that have the esteemed label of her sweet babies. Make sure to keep you cleaning appointments, she is a master at disc golf and could wipe you out with the flick of a wrist. When she’s not impressing everyone at the office you can find her listening to great music sipping a glass of vino. She’s got a smile that lights up the room and enthusiasm that is contagious. Our team is proud to call her one of our own!


Celeste Martinez- Administrative Assistant

Celeste is a huge Cowboys fan, which, incidentally, is a requirement for employment. She spends a lot of time with her family, but with the size of her family, she has to carry a cheat sheet to help remember their names. We would love to have her here forever, because there is no one better at her position, but with talent comes ambition, and her ultimate goal is to become a nurse practitioner, and she is currently taking courses to that end. In the meantime, we will enjoy helping ourselves to her mean salsa. I can taste it now. Come say “Hi” to our Celeste. She loves people, and if you are people, that means you.


Paulina Alvarado – Sleep Assistant

Paulina comes to us all the way from Irving, Texas…well, she was born in Zacatecas, Mexico, but that was a husband, a cosmetology license and a daughter named Sophia ago. She is bilingual, even though she moved here at the age of five. Speaking of the aforementioned husband, he was her brother’s best friend. Fun exercise – think of your sibling’s best friend – would it be a good match? But, I digress. They spend a lot of time playing Monopoly, even though we keep telling her that it seriously takes more than 4 houses to buy a hotel. Speaking of Monopoly, anyone reading this who can tell us how many hotels and houses there are in a game, email to enter a drawing for a deluxe game of Monopoly. She loves to travel, and we love her to travel….when it’s not a work day. We have gotten addicted to her huge smile and easy demeanor, and we don’t like a day without our Paulina.


Jerica Kennard - Administrative Assistant

With a smile that lights up the room, our Jerica will often be the first face you see upon entering the office. She has a warm, welcoming personality that will immediately help you feel at ease. That sweet nature extends beyond the walls of the office and is demonstrated in her volunteering with the Humane Society and being a full-time devoted mother to two spoiled pups. She loves hiking and biking and the outdoors in general. She’s so committed to animals and outdoor activity involvement that she even got her degree from Texas A&M in Wildlife and Fisheries Sciences (Conservation Ecology/Biology). When not saving the world or animals she still kicks back and enjoys herself doing artsy things like candle making and crafting. You’ll look forward to every visit knowing you’ll see this on-fire-for-the-world girl waiting to smile and welcome you to your dental home.


Tiara Moore - Dental Assistant

Tiara Moore is a native Texan. She is the girl that is quiet and fun combined. She has the smile that is contagious. She loves to greet her patients with a smile and ends the visit with a smile, helping to make their dental experience a fantastic one. She loves spending time with her family, including her three lovely daughters. One of her absolute loves is to frequent the restaurants from the TV show Diner, Drive ins and Dives hosted by the famous Guy Fieri. Tiara is an awesome addition to our team because is dedicated and loves to make your dental experience simple and smooth and not to add she brings the flare to our Dallas Cowboy fan base being she is a huge Green Bay fan.


Katherine Randall - Treatment Coordinator

Katherine “Kat” Randall – treatment coordinator – Kat came to us in 2017 with one thing in mind. She wanted to make 21st Century Dental & Sleep Center the premier place in Texas for all dental and sleep concerns. When we told her we were there already, she said “See how quickly I can get thigs done?” We love our Kat because she brings energy and a beautiful smile to work every day. She is a newlywed (married to Heath) with no children (yet), but the docs here act like children at times, so she has her hands full. She loves reading, and she loves wine, so reading about wine is her favorite pastime….well, except for going to musicals. At last count, she was over 100. If you ask sweetly, maybe she will sing a few bars of “Beauty and the Beast”. Come say hello to Kat, but please, no meowing. Her request. Don’t shoot the messenger.


Thu Nguyen - Dental Hygienist

Our lovely hygienist, Thu, is someone you don’t want to miss meeting in our office. Her big smile and cheerful attitude reflect the entire culture of your favorite dental office and we are thrilled to have her with us. When she’s not here she’s enjoying traveling and snowboarding with her new husband! After graduating from the Baylor College of Dentistry in 2009 she has embraced her “calling” – as she sweetly puts it – to be an amazing hygienist and mentor to her patients. Her attitude of service is outstanding and she inspires us all to follow the same role in and out of the office. Thu is known for being the “tooth whisperer” with her gentle hands and demeanor. A devoted fitness advocate and someone who maintains close ties with her family, Thu consistently strives for healthy and impactful relationships in her personal and professional life. Come meet this wonderful hygienist at your next appointment!


Aide Nunez - Dental Hygienist

Aidé Núñez – hygienist – Born and raised in Oak Cliff, and if you can name the other person at 21st born there, we will give you an extra cookie on your next visit. She has a Spanish degree from UNT, so if any of our 12 other bilingual team members are unavailable, she can translate for you. She loves to eat her mom’s enchiladas, but if you have seen Aidé, they must be low-cal, so I need to get me some of those. Married to her high school sweetheart, Juan, they love to dance and vacation on the beach. When they combine those activities, it can get quite embarrassing. Most importantly, she serves the children at her church through teaching by words and example. We know you will love Aidé, because she transfers her passion of service to the dental field, where she strives to make her patients feel comfortable with their smiles.

290 E John Carpenter Fwy. Suite 2700, Irving, TX 75062 USA
B. Kent Smith, DDS Jeff Roy, DDS Ashley Bristow, DDS Irving, TX dentist providing comprehensive dentistry & sleep apnea therapy. (972) 255-3712 (972) 255-5693