We are now advanced mate so for sure everyone can easily apply whatever they want when it comes payment method especially for digitally, because indeed all the information can be found in the internet..

However we cannot force them, i mean those doesn't have interest when it comes advance payment method because we have different perspective and we always rely which way for us is very comfortable. So i don't think it will become so easy to convince someone wherein at the first place they don't have care what technology we have now and they always preferred cash than digital money.

The same way you would educate anyone else!
You start by educating yourself and learning how bitcoin works, what wallets are safe and how you can improve the security, how fees work, how to deal with volatility, ... Then start telling others.

I would also avoid suggesting any altcoin since the issues they have prevents them from being considered a "currency" in fact many of them aren't even designed to be currencies like ETH that you mentioned in OP (it is smart contract fuel not a currency). Not to mention centralization, lack of immutability, weak security, etc. that altcoins suffer from.

It doesn't seem like dentists are the one who needs the explanation. They are already doing their jobs. Hospital administration is usually responsible for billings and payments and all business things are at their side. So first of all you need to communicate with them.
And it appears. that nowadays it is much easier to accept crypto. These clinics can even connect to BitPay and receive crypto payments in fiat and don't care about crypto.

I don't think Bitcoin payments would become a "mandatory" thing. It's an option sure, but businesses that don't really want to implement it can not do it, fiat is still there and would still be used for a long time imo. As for teaching, well, you... idk, teach them..? I don't think there's a specific method you need to use to teach people crypto stuff, it's literally just you telling them stuff and them remembering it. That is ofc, if you already know what you're talking about yourself.

As Bitcoin and other cryptocurrencies evolve, they are being increasingly accepted and adopted by a broad spectrum of consumers. In fact, recent data showed that about 46 million Americans (roughly 22% of the adult population) own a share of Bitcoin. Now, adding in other digital currencies such as Ethereum, Litecoin, Dogecoin, Ripple, ..., the amount of people who own cryptocurrencies could be even higher.

There is evidence that more people than ever are accepting cryptocurrencies. What you can expect is that more people will want to know how to pay with crypto. If you want your business to gain more customers and provide them with an easy and convenient method to purchase their goods or services, then you will need to learn how to accept digital currencies.

In order to educate entrepreneurs and businesses about how to accept crypto payment methods, there are several options to consider. One is simply reaching out to payment processors and firms that already offer these services. The other option is to use a simple payment gateway to accept payments directly to your wallet. And, the last option is to develop your own custom gateway. If you want to go in-depth, you should learn more about platforms such as GoCoin, Coinbase and more.

I don't like calling a specific sector, for example, bitcoin for doctors, firefighters, etc., but bitcoin for people who do not have technical knowledge.

There are a lot of solutions that they can use and depending on the country, the options will increase from the possibility of paying with bitcoin to the possibility of accepting bitcoin and transferring it to your bank account directly.

Also, all these features provide tools with a graphical interface that is easy to deal with people who do not have any technical experience.

this is a list of bitcoin payment processors ---> https://github.com/alexk111/awesome-bitcoin-payment-processors

To educate a dentist or anyone else how to make a payment method with Crypto is very easy. now knowledge can be obtained easily via the website or via youtube, you only need to show how the payment process uses crypto and can be implemented in payment for their services.
But before realizing this, it is necessary to remember about the regulations provided by each country. Regulations limited to trading commodities are not allowed to use payments other than Fiat, but if the country adopts crypto or bitcoin then it doesn't matter.

Perhaps officially the government was not authorized. But if you want to and the dentist agrees it could happen, but it's also against the rules. But I think dentists are not all familiar with bitcoin, providing education to them also takes a lot of time.
Maybe if you are in El Salvador it could happen officially because their government has legalized Bitcoin as payment. Actually, if you know in detail fiat transactions (banknotes coins will look efficient because it does not depend on the density of the network, besides that ordinary people are more familiar with banknotes or coins because they are often used. Some of bitcoin's concerns and weaknesses are certainly the reason the country has not accepted it.  So currently bitcoin is still limited usefulness.

So you want to say that medicine is a place where the world's most advanced technology is used to treat others. They used the world's most advanced machines. Then why not in payment? If I am not wrong, medical technology has already used advanced technology to take payment. Almost all hospitals now use digital payment methods like card payment. Online bank transactions Now comes to your opinion about bitcoin or crypto as a payment, but I don't think hospitals will be more comfortable with crypto payment. Why would they choose crypto when they can pay directly to the bank?If they choose crypto, they need to convert from crypto to bank again. To stay hassle-free, they obviously don't want to use crypto as a middle source. But it might be possible when a hospital owner gets money from a patient. If they have an interest in crypto, then they can manually invest there. There's a simple reason for this: "hospital" is a medical genre, and "crypto" is a tech genre, so they're polar opposites. But maybe it is possible in the future, but now I don't see any scope either. Thank you for allowing me to express my opinion on this subject. So i don't think there is a point to take step of hopital authority to educate their doctors about crypto. If a doctors want then he can learn by himsef.

Those professionals or businesses who already in crypto probably already accepts bitcoin as payment. Only those who knows how to use it will have an idea on accepting it in their businesses. Op can suggest and give insights to his dentist first or ask online in their nearby which dentists accepts crypto as payment so their community will be curious in this method. Just asking thru Facebook group or post can give them idea. Online payments now were popular and many is searching for kore methods on how they can coordinate it in their businesses.