Dr. Diane Anthony Costandi is a highly accomplished periodontist and clinical researcher. Her academic journey began at Pasadena City College, where she earned an Associate of Arts Degree in 2007. She subsequently attended the University of California, Los Angeles, graduating with a Bachelor of Science in Molecular, Cell, and Developmental Biology in 2009. At UCLA, she earned Latin Honors, Highest Developmental Honors, and the Chancellor’s Service Award. She also completed an honors thesis in neurobiology focused on Reelin signaling and mammary gland development.

Dr. Costandi then earned her Doctor of Dental Surgery degree from the University of the Pacific, Arthur A. Dugoni School of Dentistry in 2012. Graduating in the top one-third of her class, she received the Western Society of Periodontology Award and the Outstanding Performance in Oral and Maxillofacial Pathology Award. She obtained her California Dental Surgery license that same year. To advance her clinical specialization, she attended the University of Southern California (USC), concurrently earning a Periodontics Certificate and a Master of Science in Craniofacial Biology in June 2015. During her postgraduate studies, she conducted extensive research in periodontology, focusing on hard tissue changes after socket grafting, assessing observational study quality in periodontal literature, and analyzing antibiotic resistance profiles.

Entering private practice, Dr. Costandi has served as a Periodontist at St. Anthony Medical Centers since June 2015. She has additionally practiced as a Periodontist at Seal Beach Dental Implants from May 2021 to December 2024, and provided periodontal and implant care with Hamlin Dental Group and Dr. Marianne Tanios. Alongside her clinical work, she served as Volunteer Faculty at the USC Predoctoral Clinic, concluding her service in 2015.

In 2016, Dr. Costandi achieved Diplomate status with the American Academy of Periodontology. An active contributor to dental science, she co-authored publications on peri-implant soft tissue augmentation in 2018 and 2019. Her ongoing commitment to outstanding patient care was recently recognized when she received the 2026 top dentists award. She has maintained active memberships with the American Dental Association and the California Dental Association since 2009.