Sierra Commons Dental Group and Orthodontics at 755 West Rancho Vista Boulevard, Palmdale, California.

Rather than admitting an error in booking, they took my small child to the back for an adult cleaning with a dentist that clearly wasn't trained in pediatric dental. Rather than using the electric spinner for the cleaning, the dentist opted for the metal pick/scraper, jabbed my child and made her bleed and cry almost immediately. They also failed to notice a number of teeth that required attention, despite X-rays. Huge issue.
The 45 minute wait was the least of their problems. When asked why they booked her as an adult (after the appointment), they tried to shift blame. When asked why they didn't mention it until the end of the appointment, they made excuses.
We immediately found a better dentist, and when contacted to release X-rays, they failed to do so. If I could give them 0 stars, I would. Atrocious.