“We are committed to providing exceptional dentistry while treating each patient with integrity, dignity and compassion. We foster an environment where our employees are treated like family and our patients trust and recommend us to their family and friends.”


Joel Manalese, DDS SCHOOL: New York University School of Dentistry

UNDERGRADUATE STUDIES: California State University, Long Beach

INTEREST: Rubik’s Cubes, Tennis, and Basketball

PERSONAL QUOTE: “I value the relationships I have with my patients and commit to the highest standard of care and professionalism. I strive to make my patients happy with their smiles while providing unequivocal excellence in all aspects of dentistry. At Regal Dentistry, we are committed to excellence.”

PERSONAL BIO: When not busy practicing dentistry, he enjoys spending time with his wife and children, attending local sporting events, playing tennis, basketball, and teaching other people how to solve the Rubik’s cube. He is also an active participant in his community.

Dr. Manalese began his studies locally and received his Bachelor of Science from California State University of Long Beach in biology with a minor in chemistry. After graduating from NYU, Dr. Manalese completed a one-year general practice residency at Woodhull Medical Hospital in Brooklyn, New York, where he was awarded the Top Dental Resident of the year award. Dr. Manalese has dedicated his professional career to providing his patients with the best dentistry has to offer. He achieves this by participating in advanced training and continuing education in such specialties as Invisalign® and Lumineers®. Using advances in dental technology, including digital x-rays, intraoral pictures, root canal therapy, and teeth whitening, he will help you achieve a beautiful healthy smile for life. Dr. Manalese gives each patient personalized care and will help you make informed choices about your dental health.

PATIENT IMPACT: “During my residency in New York, I provided a patient with implant overdentures to stabilize her loose dentures. Two weeks later, she returned ecstatic to share her testimonial with our staff. She was extremely happy with the results and was in tears. She never thought in all her life she would be able to eat any of her favorite foods, like steak or corn-on-the-cob. Every time she returned for dental checkups, she thanked me for how much I improved her quality of life. She is now able to eat all of her favorite foods.”


Collin Tsai, DDS, MS Dr. Tsai began his formal dental education at the University of California School of Dentistry in Los Angeles and graduated with a Doctorate of Dental Surgery. In order to specialize in the field of orthodontics, Dr. Tsai continued on to Saint Louis University for a Master of Science in orthodontics.

Continuing education is an important part of Dr. Tsai’s commitment to his patients. Dr. Tsai regularly participates in continuing education as a way to provide the most up-to-date treatment options and highest quality care.

Originally from San Francisco, Dr. Tsai currently resides in Rancho Cucamonga with his family. He cherishes the time spent with his family and friends, and also enjoys sports, exercise, and movies.

Ronald Wright, DDS Check back soon to meet Dr. Wright! 


Robert Riegel, DDS Dr. Robert Riegel was born and raised on a farm in Western Kansas. Dr. Riegel graduated from the University of Missouri-Kansas City School of Dentistry in 1968. He practiced general dentistry in Kansas City before moving to Los Angeles in 1970 where he continued to practice general dentistry in the West Covina area.

In 1980, Dr. Riegel returned to UMKC to take specialty training in Prosthodontics, dental treatment that involves the use of crowns, bridges, removable partial and full dentures, and implants.
After he finished his graduate studies at UMKC, Dr. Riegel completed a hospital residency at UCLA where he treated head and neck cancer patients.

Upon completion of all his specialty training, Dr. Riegel accepted a part time teaching position with Loma Linda University School of Dentistry and remained in private practice in Diamond Bar, Hollywood, and Long Beach prior to assuming a full-time professorship at Loma Linda in 1990. He was in charge of teaching complete dentures and removable partial dentures to the University’s dental students. During his last five years at Loma Linda he was Section Chief of Removable Prosthodontics. Dr. Riegel was also involved in creating a program for teaching post-graduate dentists who wanted to specialize in prosthetic and implant dentistry.

In 2000, Dr. Riegel resigned his full-time position at Loma Linda to dedicate his time to his patients in private practice and specialize in dentures and implant placement.

Dr. Riegel is semi-retired from Regal Dentistry.

Meet Our Team

Our friendly team of dental professionals are committed to giving you the best experience possible when you visit Regal Dentistry.  Our mission is to provide each patient we meet with a unique, individualized experience, and we take the time to get to know you and earn your trust – we care about you as our friends, and not only as our patients.  We also speak Spanish!  Please give us a call at 951-888-5805 to learn more about dental care in Riverside, California, and make your appointment with our caring dentists.

Joyce, Hygienist

Joyce Dabuet – Registered Dental Hygienist Joyce is one of Regal Dentistry’s benevolent registered dental hygienists. In 2002, she graduated with a Bachelor of Science degree in dental hygiene from the University of Southern California Herman Ostrow School of Dentistry. Joyce has over 15 years of clinical dental hygiene experience under her belt. She has worked in a busy periodontal practice and various general dental offices throughout her career. As a result, she has had the pleasure of working on patients from all walks of life, ranging from children’s mobile clinics to veteran’s hospitals and the Union Rescue Mission (a private homeless shelter) to working on high-profile patients, such as celebrities and famous sports athletes. Rest assured, Joyce’s mission is to treat patients like her own family, with the utmost respect and care. She is a compassionate, gentle yet extremely thorough dental hygienist. She also has a fervor to educate patients on the importance of understanding and maintaining excellent oral health care. Joyce is in full agreement with the saying, “You only have to floss the teeth you want to keep!”

Outside of the dental office, you can find Joyce’s hard work ethic shine through in her fitness regime. In 2012, after competing in seven shows, Joyce earned the prestigious “IFBB procard” (professional status in the bikini division of the International Federation of Bodybuilding and Fitness). One can certainly see why she strives to keep up her physical stamina, as she is the mother of three energetic children and wife to an LA city firefighter/paramedic, who is also a men’s physique division competitor.

Along with her love for fitness, Joyce enjoys world travel and is quite the foodie! She recently exchanged high-rise, downtown living in Los Angeles for more space and the subdued suburban lifestyle of Riverside. Next time you visit Regal Dentistry for your dental hygiene cleaning, please do not hesitate to share your favorite world adventures and restaurant recommendations with Joyce!


Sonia Gomez – Hygienist Sonia attended Pasadena City College and graduating in 2012, earning her Registered Dental Hygienist degree. She has been practicing in Southern California for over four years and loves her career. Sonia’s number one goal is to treat every patient with compassion and care. She loves making patients feel comfortable at the dental office. There is nothing more satisfying than helping people improve their smile. Sonia loves being a part of an awesome team. Our team welcomed her with open arms and has made her feel as if she has been working with us for many years. Everyone is so nice! In her spare time, Sonia enjoys spending time with her son.


Nadine Posthumus – Hygienist My name is Nadine Posthumus. I attended Loma Linda University where I earned my Bachelors in Dental Hygiene. I am originally from South Africa and my first language is Afrikaans. My passion is to help improve the lives of those around me and my specialty is to help improve the oral health of my patients. When I am not coaching family on brushing and flossing techniques, I like to play boardgames, run, and cook. Thank you for letting me share my background with you! I am honored to be apart of this wonderful Regal Dentistry team and I am excited to help you reach your oral health goals.


Ofelya Manalese – General Manager OGeneral Manager Ofelya was born and raised in the capital city of Armenia, Yerevan. In 2003, she earned her bachelor’s degree in management, soon after, she moved to the United States. While she was
continuing her education at City University of New York, she met her husband, Dr. Manalese, and they started their lifelong journey together. In 2013, Ofelya began working with Dr. Manalese, helping him with general management and daily practice operations. She is very compassionate about providing our team with the best workplace environment, ensuring that we all work towards one goal; to provide the best care to our patients.

Ofelya loves raising their three children in Southern California, where the kids have various opportunities to participate in sports and diverse cultural activities. Their oldest son loves playing soccer and recently joined a soccer club to play at a more competitive level. He also enjoys singing, acting, dancing, and gymnastics. Their daughter loves going to dance class and also enjoys gymnastics. The little one is a trooper who can’t wait for his turn to join in on all the activities his older brother and sister get to do.


Karlina Manalese – Director of Patient Services Karlina graduated from California State University, Fullerton in international business. Karlina works with our team to provide the best patient experience possible. She strives to make sure that all of our patients’ concerns have been thoroughly discussed and that they understand their treatment options. Karlina loves working here because our team is like no other. We are truly a family here. We want our patients to feel that they are an extension of our work family. Our team is committed to providing the best care available, not compromising on any level, and giving our patients the highest level of satisfaction possible.

Karlina is the proud mother of three. Her daughter, Romina, is attending college at California State University, Fullerton (CSUF), majoring in business marketing. Her son, Marcel, is in high school and wants to follow in his uncle’s footsteps and become a dentist. Karlina’s son, Jayden, is an avid baseball player and travels to many tournaments. When not in the office, Karlina loves to travel and experience other cultures and traditions.


Rosa Herrera – Office Coordinator Rosa has been a treasured member of our dental team for over five years. She can honestly say that she’s enjoyed every day of her time with us! Rosa educates patients on how to get a beautiful smile. Rosa helps patients have a one-of-a-kind experience. Having patients leave happy is her greatest satisfaction. Our dental team is a second family to her. We like for our patients to feel like part of the family as well. Rosa loves working with our great doctors and team.

As a mother of three boys, Rosa keeps herself busy. When not at work, Rosa likes going to amusement parks, watching movies, and playing sports with her family.


Ashley Ousley – Treatment Coordinator and Dental Assistant Ashley studied dental assisting at Concorde Career College. She is our patient advocate, and has more than 3 years of experience assisting in dental procedures. She works hard to get to know our patients, learning about their specific needs and goals in order to assist them in determining which treatment option will be most effective for them. For Ashley, the best part of our practice is feeling like part of a family.

When she isn’t in the office, Ashley enjoys going to the gym and going to movies.


Amver Espiritu – Lead Dental Assistant Amver has been working with Dr. Manalese for over 6 years. He graduated from UEI College with a degree in Dental Assisting in 2011. Over the years, Amver has not only proven to be a great dental assistant and team player, but also a goal-oriented and dedicated leader. Being the lead dental assistant, he ensures that the back office runs smoothly and that patients receive an excellent experience. He also makes sure to build extreme efficiency in
patient flow. Amver enjoys his work and the different challenges he faces for each and every patient.

In his spare time, Amver enjoys playing basketball at the local park and trying out different types of foods from various cuisines. In addition, his favorite thing to do is road tripping and appreciating mother nature and the country’s amazing national parks.


Christian Quinonez – Dental Assistant Christian is a local of Riverside, California. He graduated from Perris High School, then received his degree as a Dental Assistant from UEI College. For over three years, Christian has been a member of our team at Regal Dentistry. As a dental assistant, he helps out with both the front and back offices, making sure that all supplies and equipment is ready for our patients. Christian is very thorough in all his work, especially when he is explaining procedures to patients as a way to help them relax and feel as comfortable as possible. Christian loves what he does; he loves working with the amazing team and learning something new from the doctors every day. He enjoys being part of a team that works together to provide the best patient care possible.

Christian is a sports enthusiast! When he is not working in the office, he is often spending time with his family and taking his 9-year-old son to baseball games. Christian is also a huge Cowboys football fan, and he enjoys listening to different types of music.


Sara Denis – Dental Assistant Sara joined our team at Regal Dentistry in 2016.  She completed the Chaffey College Registered Dental Assistant program, and interned at Loma Linda University.  She makes it her goal to continue to learn and grow, and continues to advance her dental education regularly.  Sara loves being able to make our patients more comfortable and less anxious about their time in the dental chair, and brings an upbeat, positive attitude to our office every day.  She is passionate about dentistry, and loves developing personal relationships with our patients.  Sara and our team members are very close, and we all work together to give the very best service.

Sara loves her family, and she is very close with her dad and sister. In her free time, she enjoys camping and going on vacations.

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