in $S_g$, we mean a finite collection of disjoint non-isotopic essential simple closed curves in $S_g$. Let $t_c$ denote the left-handed Dehn twist about an essential simple closed curve $c$ on $S_g$. Since the Dehn twists about any two curves in ${\operatorname{{\mathcal{C}}}}$ commute, we will define the *left-handed Dehn twist about* ${\operatorname{{\mathcal{C}}}}$ to be $$t_{{\operatorname{{\mathcal{C}}}}} := \prod_{c\in {\operatorname{{\mathcal{C}}}}} t_c$$ A *root of $t_{{\operatorname{{\mathcal{C}}}}}$ of degree $n$* is an element $h \in \text{Mod}(S_g)$ such that $h^n = t_{{\operatorname{{\mathcal{C}}}}}$.

When ${\operatorname{{\mathcal{C}}}}$ comprises a single nonseparating curve, D. Margalit and S. Schleimer [@MS] showed the existence of roots of $t_{{\operatorname{{\mathcal{C}}}}}$ of degree $2g - 1$ in ${\operatorname{Mod}}(S_g)$, for $g \geq 2$. This motivated [@MK1], in which D. McCullough and the first author derived necessary and sufficient conditions for the existence of a root of degree $n$. As immediate applications of the main theorem in the paper, they showed that roots of even degree cannot exist and that $n \leq 2g -1$. When ${\operatorname{{\mathcal{C}}}}$ consists of a single separating curve, the first author derived conditions [@KR1] for the existence of a root of $t_{{\operatorname{{\mathcal{C}}}}}$. A stable quadratic upper bound on $n$, and complete classifications of roots for $S_2$ and $S_3$, were derived as corollaries 