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Contact us: 281-599-1755

 Meet Our Team

John Siu, D.M.D.

Dr. India Holman A Canadian native, Dr. Siu grew up in the city of Vancouver where he attended the University of British Columbia. He received a Bachelor of Science degree for his focused studies in Microbiology, Immunology and Psychology. His passion for travel eventually led him to later reside in Boston, Massachusetts. He pursued his Dental Medicine Degree at the Boston University Henry M. Goldman School of Dental Medicine, where he graduated Summa Cum Laude.

He is dedicated to the newest advancements in dentistry and keeps up-to-date with the latest technologies. He is frequently attending courses in postgraduate dentistry to provide patients the benefits of advanced techniques and equipment.

As a cosmetic and restorative dentist, Dr. Siu provides patient services not limited to oral surgery, removable dentures, orthodontics, dental fillings, crowns and bridges. His thorough and attentive approach helps his patients feel at-ease while they are receiving care.

Dr. Siu is a standing member of the American Dental Association, Massachusetts Dental Society, and Greater Houston Dental Society. Locally, he is a member various civic organizations.

When Dr. Siu is not practicing his passion of dentistry he spends most of his time with his friends and family. He is an avid tennis player and loves water sports.

Certification/Professional Memberships

  • Bachelor of Science - University of British Columbia 
  • Dental Medicine Degree – Boston University 
  • American Dental Association 
  • Massachusetts Dental Society 
  • Greater Houston Dental Society

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Stephanie Wilson, DDS - Orthodontist

Dr. India HolmanDr. Wilson was born the second of three children to James and Lillie Wilson in Lake Charles, LA. Growing up with parents who were born in rural Louisiana, Dr. Wilson was made aware of the disparity and lack of access to dental and medical care. She decided early on that she wanted to pursue a career in the dental field. She graduated, with honors, from Grambling State University with Bachelor of Science in Biology/ Pre-Med/Pre-Dental.

Still driven to reach her goal of becoming a dentist, Dr. Wilson attended Meharry Medical College School of Dentistry in Nashville, TN. While at Meharry, she received several honors, one of which was induction in Omicron Kappa Upsilon Dental Honor Society. She graduated from Meharry with a Doctor of Dental Surgery Degree in 1997.

After graduation, Dr. Wilson decided to move to Houston and became a General Practice Resident at the Houston Veteran's Hospital. And under the urging of her program director, Dr. George Goeff, Dr. Wilson decided to become an orthodontist. She attended a 2 year residency program at Howard University College of Dentistry in Washington, DC where she received a Certificate in Orthodontics.

Upon completion of her education in 2000, Dr. Wilson realized it was time to start her career as an Orthodontist. She once again moved to Houston because she loved the area and its closeness to Lake Charles, her home. In 2005, she married one of her high school classmates, Mr. Stephen Orphey, who is a graduate of Louisiana State University with a Bachelor of Science Degree in Industrial Engineering.

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Gregory Pham, DDS, MD - Oral Surgeon

Dr. Gregory PhamDr. Gregory M. Pham is the only oral and implant surgeon in the Houston area with the distinction of having postgraduate training that include general surgery as well as neurological surgery. He received his doctoral of dental surgery from the University of Texas Health and Science Center in 1997. After graduating from dental school he began postgraduate training in Oral and Maxillofacial Surgery at Wilford Hall Medical Center in San Antonio and at the Texas Medical Center from 1997-2001. In 2005, Dr. Pham was granted acceptance into medical school in Tampa/Bradenton, Florida and matriculated until he earned his medical degree in 2009. Following medical school, he was accepted into a traditional general surgery internship followed by a neurological surgical residency under Javed Siddiqi MD, PhD program director at Arrowhead Regional Medical Center in San Bernardino, California. During his neurosurgery residency, he rotated through the program affiliated hospitals which include Kaiser Permanente of Fontana, Riverside Community Hospital, Redland Community Hospital, Desert Community Hospital; and Loma Linda Medical Center. In 2011, Dr. Pham forgoes his neurosurgery residency and returned to the Houston to practice of dentistry because of his desire to start a family.

His practice focuses on implant surgery, complex bone grafting techniques, all on four dental implants procedure, third molar extractions and intravenous sedation, as well as an expert in the techniques of botox and dermal fillers. He is a Fellow of the American College of Surgeon, a Fellow of the American Dental Society of Anesthesiology, Master in the International Congress of Oral Implantologists, actively working toward gaining fellowship status in the near future, memberships in the American Medical Association as well as the American Dental Association. He has successfully completed courses at the University of Texas Health Science Center maxi-implant course, Misch Implant Institute course, the Zimmer Fully Stimulated Comprehensive Implant Placement Course as well and Piko and Salaman Advance Bone Grafting course.

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Cristina Xydas DDS, MS - Periodontist and Implant Dentistry

  “My career revolves around your SMILE. I will create the foundation for your dentist to make your smile beautiful as well as functional. Ultimately you will feel good about yourself and smile more.

 From the moment you walk through my door you will feel the warmth, the confidence and the knowledge that will guide you throughout the entire treatment. This is what you will always get.”

Dr. Xydas performs the following types of treatments:

  • Dental Implants
  • Periodontal soft tissue and bone regeneration
  • Surgical and non-surgical treatment of periodontal disease
  • Cosmetic periodontal procedures
  • Bone grafting and ridge augmentation for implant placement
  • Extractions with socket/ ridge preservation
  • Sinus elevation to grow bone for implants
  • Corticotomy to accelerate orthodontic treatment

General Dentistry Education

  • University of Medicine and Pharmacy “Carol Davila” Dental School, Bucharest, Romania
  • General Dentistry residency – 2 years

Periodontal Education and Training

  • Master Degree and Certificate in Periodontics from Boston University “Henry M. Goldman School of Dental Medicine” – three year program
  • Preceptorship in Periodontics – University of Texas Dental Branch – Houston, TX
  • Assistant professor in Department of Periodontology, University of Medicine and Pharmacy “Carol Davila” Bucharest, Romania
  • Master thesis in basic science: Expression of Connective Tissue Growth Factor in Gingival Epithelial Cells and Fibroblasts.
  • Represented Boston University at the Trischool Symposium in Philadelphia with a presentation about Distration Osteogeesis

Certifications and Skills

  • Advanced Cardiac Life Support Certificate
  • Fluent in English, Romanian
  • Can communicate in Spanish, Greek

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Our Staff

Our team consists of dedicated individuals who are kind, friendly and caring. Our staff's here to ensure a pleasant experience during your visit to our office. The team includes experienced and energetic people whose goal is to communicate with our patients to provide the best care possible.

Viviana Salgado
Office Manager

Viviana has been with Katy Dental for over 10 years. She is well versed in all aspects of dentistry and continues to stay up to date by attending dental seminars. She is bilingual in English and Spanish. Viviana is very close to many of our patients and their families. She enjoys fishing, riding bikes, and spending time with her husband and 2 sons. Congrats to her and her family on their newborn son!

Rodney Lara
Head dental assistant

He has 18 years dental assisting experience. He likes spending time with his boy and girl. He is bilingual in English and Spanish.


Karina O.
Registered Dental Assistant

Karina is a 2009 graduate of Lone Star College, where she received her dental assisting certificate. She loves the hands-on approach our team takes with patients and loves seeing people leave our office with a big, beautiful smile. Her caring, detail-oriented personality ensures that our patient’s dental health and comfort remain her central focus. When not in the office, she enjoys spending time with her friends and family and attending college. She is bilingual in English and Spanish.

Vanessa Rivera:
Registered Dental Assistant

With more than 3 years dental assisting experience, she is really confident when helping doctors with all types of dental treatments.

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Katy Dentists - ph. (281) 599-1755

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