True.

Thanks for quick reply and your opinions I appreciate that. I am agree
with you regarding not to wait until infection go up to root.

However, I have one more question. is filling process has any side
effects ? or is it sure filling will stop infection (stop rusting) ?
Best Regards,
Sanjay

Not to mention the fact that usually, the smaller it is, the stronger
the tooth is. The tooth will support the filling and there is a good
chance you will never have to touch it again. If you wait until the
tooth is weakened by the caries undermining it, then you'll need a
filling or crown that will support the tooth. (The filling has to
support the tooth, instead of having a naturally strong tooth with a
small filling).

In one phrase: being conservative usually means treat it now when it's
small and easy to do.

Re: side effects: Chances are you won't even need to be frozen for this
procedure. No side effects of anesthesia (itching, small irritation at
the site of injection, usually minor and of no consequence). I would try
to place a composite (more conservative than an Amalgam filling, unless
the hole is already a couple of mm wide.

Side effects of Amalgam: there is Mercury in it and we don't know what
that really does, although the only real scientifically controlled
studies I've seen point to more risk to the dentist than to the patient.
That's because when we drill out and place Amalgam fillings in your
mouth, we inhale the dust. That's why you see pictures of dentists with
oxygen masks on their faces in some of these web sites. (rediculous,
IMO, if the treatment rooms are well ventilated).

Side effects of composite: the resins we use contain monomers and
chemicals that resemble estrogen compounds. This means you may be
exposed to weakly estrogenic activity coming from the filling. I first
heard of this a few years ago, but it does not seem to have become a
real issue: Patients with a lot of composite fillings in their mouths
don't seem to be affected by any estrogenic activity of the materials.
This makes my question whether or not there is any real effect. It's
getting to the point where I don't listen to laboratory researchers
much, any more, as the work they do and the findings they report are
often not really relevant.

The bottom line: if it were my tooth, I'd say treat it now with
composite with no hesitation what so ever. The same recommendations
would apply if it was my young children. If the caries was in an area
where the gum tissue would produce bleeding when cleaning the decay out,
I would not hesitate (in the adult) to place an Amalgam, if I couldn't
control the bleeding or the saliva.
Hope I've helped you decide.
SP