Not all of it is based on true stories. It's a mix of fictional elements and possible inspirations from real-life incidents, but it's not a straightforward documentation of actual events.
Since I'm not familiar with this particular graphic novel, it could cover a wide range of themes. It may revolve around the dentist as a central character, showing their work - life balance in the context of their home. There could be stories about the history of the house and how it became a dental practice. It might also depict the community around the house and how the dentist and the house are perceived by the neighbors. It could be a story full of human interest, with the dentist's house serving as the backdrop for all kinds of interactions, emotions, and events.
Not having read the graphic novel, it's pure speculation. The main characters could include the dentist, who is probably central to the story. There might be a nosy neighbor who is always curious about what goes on in the dentist's house. Also, if there are any apprentices or trainees in the dental practice, they could be main characters. Maybe there's a patient with a phobia of dentists who has a character arc throughout the story.
I'm not sure. It depends on various factors and how the story was presented. Sometimes stories are based on real events but might have some fictional elements added for entertainment.
La Casa de Papel is completely fictional. The plot, characters, and situations were all crafted by the writers for entertainment purposes. There's no real-life basis for it.