Hello Dear Client
Let us show you and expain to you our project.
Since you are a Dentist we designed the space to be mostly white so all rooms have enough light, look very elegant and it goes well with medical professions. Light simply bounces of the white walls. Also by health regulations you must have light colours so to show that everything is clean. What isn't white, is light grey, to give a little more color. In every corner we are thinking of light. When your clients enter your dental clinic the first thing they see is a cozy waiting are and the reception, the hallway to the left, towards the offices and surgery room. The waiting area has space for 8 people(4 on one sofa, 3 on the other and 1 on the armchair) so it has enough space for clients and their friends and family waiting for them. The sofas are white and made of leather and make a clean and cozy atmosphere, and because they are leather, they absorb less dust and bacteria, so they promote the hygeine of your office. Right next to the secretary is the toilet for clients.The door is 150cm wide and opens to the outside(into the waiting area), which is a common regulation for accessible bathrooms, which can be used by clients in wheelchairs. On the bathroom walls handles are placed, so it is fully equiped for all clients. The bathroom is placed here so the secretary can easily show it to clients, and it's furthest wall is placed at the wall with pipes. That way everything is more fluent and practical. And most important, if someone needs help to get to the toilet she can easily come out and help, even wait for the client to come out from the toilet, since she is near the reception and can do her job while standing and waiting. That is a big plus for customer service and the news of such a friendly clinic will be sure to spread quickly through town. As you said that the secretary needs her office, for back-office work she has one right next to her. In there she can put away documents and files, and her coat when coming in to work, also she can do the private paper work when needed, and sort the files in the large shelves.That room can also host a little kitchen in which the secretary can make you tea coffee. Or you can hire one more worker for paper work, if needed, and he will be in there. The reception is connected to the staff toilet with a sliding door so she can use it whit no problems and dosent need to come out of the recepcion. A simple banner on the door saying "Back in 5 minutes" will suffice. But she can also use the client toilet if she wants. The sterilization room and both toilets are sharing the same wall as to use the pipes that are there. The sterilization room doesn't have a window so that sunlight doesn't harm the equipment and machines for sterilization. When your client comes for his appointment, the secretary just shows him the hallway, that is where all the room doors are. With this design there is no way someone can get lost in the dentist officery. Every door has the doctors name and use of room labeled and the sterilization and x-ray rooms have special signs. Or the secrretary can show the client their way, she can see the entrance door from the hallway and knows if any knew clients enter. Or even better. The secretary tells the client to go down the hall and simply informs by microphone/telephone to the doctor that the client is coming and the doctor opens the door for him to know where to come in. The changing room is also there, it is efficient. It is small and meets standards needed by the laws you gave us. Not to forget to mension : ALL THE ROOMS ARE IN COMPLIANCE WITH THE LAWS that you gave us, the rooms are all larger than 9sqm, the sterilization and x-ray room are around 5sqm. So you wont have problems with the construction workers or inspection. You are good to go. The other 3 roooms that you have are the offices you need for your dentiist operations. Every room has a dentist chair, with all the necessary gear and a stool next to it, for the dentist. The smallest room, which is mostly for check-ups and short interventions also has a desk and chairs for you and your client to talk about prescriptions and interventions. All the offices have a sink for washing hands and equipment and enough shelving/closet space for supplies and files. ALL THE ROOMS HAVE SLIDING DOORS. We calculated the needs for the doors to slide in. It is possible so we used this enormous benefit. You can have a much nicer and flexible room since the doors just slide in the wall. And also this is a plus with the inspection since sliding doors are much more hygenic and less hazardous. Plus they give a touch of modern/luxury dental clinics so you will be soon in the eye of the public and have more customers. Even kids that don't like to go to the dentist will come to look amazed at the high tech doors, since only your clinic has them. That is always a plus to the parents. "Word of mouth" is the best advertisement, and no money can buy that. With that kind of floor plan you and your colleagues can work together easily, and even join in with one more dentist, or better yet get a dentist student to work with you, since you have 3 offices. Dentist can also come to the recepcion office and do their work until the client comes when they show him the way to the office. All the offices have the best possible sun light solution, and blinds that can be set when you don't need sunlight. Only the sterilization, x-ray and changing room don't have windows, the sterilization can be harmed by sunlight and the changing is used very little so it would be a waste. We used all the windows for rooms that are 24/7 used. We used white vinyl carpets since they show how clean the room is, they are also very durable, they don't absorb dust or bacteria and are easily washable, overall they provide very good hygiene. The hall is very long due to the apartments shape, but this can be a good thing, because it means that very few people walk through it(only clients and dentists) and it will stay very clean. That way there is a split zone betwen the dentist room and everyday clients in the waiting room. The waiting room and hall have a floor composed of white, glazed tiles because they don't have much sunlight and they should be easily washable.

As a Bonus here you go a video clip for your pleasure and to help your builders to understand the space and how to make it as needed.
https://www.youtube.com/watch?v=ZzOycg8qtJM&feature=youtu.be
Regards