Increase in temperature

$\Delta \mathrm{T}=57-37=20^{\circ} \mathrm{C} \text { or } 20 \mathrm{~K}$

Coefficient of linear expansion of cavity, $\alpha=1.7 \times 10^{-5}{ }^{\circ} \mathrm{C}^{-1}$

Bulk modulus of cavity $\mathrm{K}=140 \times 10^{9} \mathrm{~N} / \mathrm{m}^{2}$

Coefficient volume expansion of copper,

$\gamma=3 \alpha$

$=3 \times 1.7 \times 10^{-5}$

$=5.1 \times 10^{-5}{ }^{\circ} \mathrm{C}^{-1}$

Suppose the original volume is $\mathrm{V}$ and the increase in volume is $\Delta \mathrm{V}$ due to increase in temperature $\Delta \mathrm{T}$.

We know that,

$\Delta \mathrm{V}=\gamma \mathrm{V} \Delta \mathrm{T}$

$\therefore \frac{\Delta \mathrm{V}}{\mathrm{V}}=\gamma \Delta \mathrm{T}$

Thermal stress $=$ Bulk modulus $\times$ volume strain

$=\mathrm{K} \times \frac{\Delta \mathrm{V}}{\mathrm{V}}$

$=\mathrm{K} \times \gamma \Delta \mathrm{T}$

$=140 \times 10^{9} \times 5.1 \times 10^{-5} \times 20$

$=1.428 \times 10^{8} \mathrm{~N} / \mathrm{m}^{2}$

Atmospheric pressure is $\mathrm{P}=1.01 \times 10^{5} \mathrm{~N} / \mathrm{m}^{2}$. Hence, the pressure in cavity of teeth is approximately $1000$ times than that of atmosphere.