The thought that you will get dirt entry into an engine if you live on a dirt road really puzzles me. There should be zero dirt entry, any amount of dirt is detrimental to a internal combustion engine.
How does it get in? Why would it only get in on a dirt road?
Construction equipment and farm equipment operate in dirty conditions with zero dirt entry. If you have dirt entry into the engine something is wrong.
If you want to change your oil just in case it may have dirt entry, it does little good. The damage is done if you have dirt entry.
Most of the dirt entries I have encountered are on the intake side of things. So the dirt entered the engine in the air fuel mixture and does it damage there, in the cylinder. This inturn increases wear on the cylinder and rings first, its what is called dusting a engine.
Short story, one can change the oil but the cylinders are still dusted. It might save the bottom end but not for long the dirt has already accelerated the wear.
If one suspects dirt entry, Spend the $$ on a oil analysis to determine if you have dirt entry, if the OA shows high silicone, you have dirt entry and you must find where it is entering the system.
Granted my experience is in off road equipment but it is all relative.
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