"Dr. Oza completed an emergency root canal procedure on one of my front teeth. The work he did was flawless, and his bedside manner is second to none. I cannot recommend him any more highly."
Ben L.
Specialized care to relieve tooth pain and help save your natural tooth.
Featured Treatment Available at all 4 locations
GentleWave root canal.
One visit. Exceptional outcomes.
GentleWave reaches the parts of your tooth that traditional files physically cannot. This means treatment is minimally invasive compared to traditional root canal treatment, which requires more tooth structure to be removed. It disinfects the entire root canal system in ways instruments alone never could. I've tried varying disinfection systems in 28 years of practice. In my opinion, nothing comes close.
"Field-changing. That's how I would describe it." We make GentleWave available to every patient at our 4 locations. Every doctor in this practice is proud to offer this technology as the new and elevated standard of care.
Learn About GentleWave
96.6% of patients report mild to no pain after the procedure — Sonendo, data on file. The pain most patients fear going in is the infection they arrived with. Not the treatment.
"Today, we are successfully saving teeth that would have been lost in the past. Our state-of-the-art treatments are redefining what is possible for the longevity of your teeth and your overall health."
— Dr. Priya O'Callaghan, Owner96.6% of patients report mild to no pain after their GentleWave procedure. The pain most patients fear going in is the infection they arrived with — not the treatment.
Sonendo, data on file
Owner — Dr. Priya O'Callaghan
28 years. Her word.
28 years. Her word.
Her conviction.
Endospecialists has been proud to serve our patients and referring dentists since 1974. Dr. O'Callaghan has led Endospecialists since 2003 and is proud to remain East Bay's largest private independent endodontic practice — seven specialists, four locations, a referral network of over 300 dentists, and 98% of patients arriving by referral. That's not marketing. That's more than 50 years of honest results.
She earned her specialty degree from the University of Southern California and dedicates four days a week to direct patient care. What truly sets her apart, however, is her accessibility: when your referring doctor needs to reach her, she picks up the phone. This is her practice, her reputation, and she makes sure the lines of communication are easy and open.
Meet Dr. O'Callaghan"She was precise, focused and meticulous, but above all, she was warm and attentive to any of my reactions."
Independent Practice
"We're the East Bay's largest private endodontic practice. Private equity partners have a legal obligation to their shareholders. My team has a legal and ethical obligation only to our patients. Patients have a right to ask who owns a practice."
Endospecialists is independently owned. We have not sold to private equity. That's a choice Dr. O'Callaghan has made deliberately, over 28 years, because she believes the treatment room should answer to the patient — not to a board of investors.
Every treatment decision Dr. O'Callaghan and her team make serves you — our patient. When you have a question, you speak to a familiar team member right here in our office, who knows exactly who you are.
Seven things patients say matter most — and why
we built for them.
Across four locations, over 600 of our patients have left Google reviews, with scores of them spontaneously writing 'highly recommend.' These are the seven core reasons they shared—the exact reasons why our patients arrive anxious and leave confident.
- 01 Full Technology Suite — Every Location Patients who visit our Berkeley, Hayward, or El Cerrito offices receive the same treatment as those seen in Oakland — without being redirected to another office. That's by design: the same state-of-the-art technology, including GentleWave, CBCT imaging, EdgePro Endodontic Laser, and surgical microscopy, is available at all four locations, every day.
- 02 Same-Day Emergency Access The reviews that mention pain almost always mention the same thing: they were seen that day. We hold same-day slots for pain cases at all our four locations — our Oakland office is open Saturdays.
- 03 Independently Owned What patients notice — without knowing why — is that nobody rushed them, nobody pushed a treatment they didn't need, and the recommendation felt like it came from a doctor, not a system. That's what independent ownership looks like from the chair.
- 04 Trained to One Standard Patients who saw different doctors across different visits said the same thing: the standard didn't change. Dr. O'Callaghan trained at USC and has spent 28 years building a collaborative network of specialists around a single philosophy: when a treatment is complete, it must be the absolute best work possible.
- 05 GentleWave The reviews that stand out most are from patients who'd had a root canal before — somewhere else. They expected the same experience and got something completely different: minimal visits, mild to no discomfort, back to normal the next day. That's GentleWave — recommended to every patient at every location since 2019, and accepted by nearly 100% of our patients.
- 06 28-Year Referral Network Most of our patients come to us through their dentist. That trust — between our team and the dentists who refer to us — is earned slowly: over 300 referring relationships, built over 28 years through personal contact and clinical results alone. Just word-of-mouth.
- 07 4-Location Scale, Private Values Patients consistently note two things that seem contradictory: they were seen quickly, and they didn't feel rushed. Four locations gives us the capacity for same-day emergency care; independent ownership means every case still gets our personalized, undivided attention.
Our Team
Specialist doctors.
Specialist doctors.
One practice.
The doctors below didn't all come from the same school or the same city. They're independently contracted specialists who chose to practice together. What they share is a standard Dr. O'Callaghan brought with her when she joined in 2003, and one this practice has held since 1974: when the treatment is complete, it should be the best that could have been done.
Patient Reviews
What our patients say.
Over 600 five-star Google reviews.
"I have had two root canal therapies done by Dr. O'Callaghan. I'm very impressed by her skill, persistence, patience and humor. She has a great bedside manner and is incredibly competent. In short, she's great!"
Emily T.
"Dr. Fujimura is an excellent endodontist! He makes patients feel at ease."
Alise J.
"Had a great experience with Dr. O'Callaghan. She explained all the steps and the procedure went smoothly. Recovery time was fairly minimal."
Mikie H.
"Excellent team. Everyone is professional, welcoming and kind. I can't believe how little discomfort I experienced. Dr. Kathpalia and my incredibly gifted assistants took very good care of me."
Lynette G.
"When you need to have a root canal done through a crown, you want a pro. Endospecialists put me at ease through the entire process. I would be happy to go back if I needed it again. They are top notch."
Julie Ann B.
"I had a great experience, Dr Kim explained everything and made me comfortable with a procedure I dreaded. But keeping your teeth keeps your mouth stable and youthful. A natural tooth is much better than any substitute"
Clement A.
"I had a really great experience from the front desk to the staff up to my consultation with the specialist. A very knowledgeable, professional, and friendly team. I would definitely recommend their service."
Denise B.
"Dr. Kim is highly skilled, so I felt that I was in capable hands. I recommend him highly, especially to those who are fearful about having dental work done."
Leslie
"Gentle, swift, professional. This is the best dental experience you can ask for."
Thomas W.
"Everyone is very nice and helpful. The front office person, the dental assistant and Dr. Fujimura is awesome. Great office!"
Drea W.
"Thank you for your awesome work and making me feel comfortable. The assistant I had deserves a shout out as well. Thank you for your care."
Nicole E.
"I can't thank the team here enough, I came in in a lot of distress and they saved the day!"
Ryan L.
"Amazing care and very knowledgeable. Helped me after I fell and dislocated my teeth and needed two root canals. Thorough, smart and great care."
Marianne C.
"Dr Fuji and Nicole worked on my 9year old for a pulpotomy. They were kind and patient with him and answered all our questions. My kid’s pediatric dentist agreed with Dr Fuji’s treatment plan. We are happy with our experience there."
Elle
"Excellent treatment and great customer service. The procedure went flawlessly; I am extremely satisfied with Endospecialists doctor and staff."
Mary P.
For Referring Dentists
Refer with confidence.
Refer with confidence.
Your reputation is safe here.
Endospecialists has maintained referral relationships for over 50 years — over 300 practices across the East Bay. Referring dentists know their patients will get the same thing every time: thorough, attentive care and results they can stand behind.
Latest technology at every location. Specialist to General Dentist communication after every case. Collaborative care to support your patients and practice.
Four Locations
East Bay endodontic care —
Main Office
Lower Level 01
Oakland, CA 94612
View Location
#727
Berkeley, CA 94705
View Location
#2
El Cerrito, CA 94530
View Location
Suite 101
Hayward, CA 94541
View Location
East Bay endodontic care —
close to where you are.
Oakland
222 14th StreetLower Level 01
Oakland, CA 94612
Berkeley
2999 Regent Street#727
Berkeley, CA 94705
El Cerrito
6431 Fairmount Avenue#2
El Cerrito, CA 94530
Hayward
1290 B StreetSuite 101
Hayward, CA 94541