what is the way to make a sqbullet in itemize structure

Question

First of all, when I want to use an itemize structure in simply latex document I have not this problem, I mean, I got sqbullet in itemize list. But.. when I inlcude a tikz picture, maybe, I load some packages and then I got dots in itemize list. For this reason, I would like to know how to get sqbullet in this cases. I´ve tried

\begin{itemize}
    \item [\sqbullet] A
\end{itemize}

or somethin like this How to change the nested itemize bullet characters?

But I didn´t. Thank you in advance!

Answer 1

[ Just to answer the unanswered, converting comments into an answer ]

Load the mathabx package as the last one and remember to use \sqbullet in math mode:

\begin{itemize}
    \item [$\sqbullet$] A
\end{itemize}

Answer 2

Since loading mathabx changes the appearances of several maths symbols, you can also just use the relevant parts of the package, as explained here:

% From mathabx.sty.
\DeclareFontFamily{U}{mathb}{\hyphenchar\font45}
\DeclareFontShape{U}{mathb}{m}{n}{
      <5> <6> <7> <8> <9> <10>
      <10.95> <12> <14.4> <17.28> <20.74> <24.88>
      mathb10
      }{}
\DeclareSymbolFont{mathb}{U}{mathb}{m}{n}

% From mathabx.dcl.
\DeclareMathSymbol{\sqbullet}{1}{mathb}{"0D}

and then use \sqbullet as proposed in the other answer:

\begin{itemize}
    \item [$\sqbullet$] A
\end{itemize}