The aim of this study is to evaluate the ability of fibre optics in measuring nano-strains developed in dentistry due to small chewing force. Since long fibres were used before, therefore, short fibres were evaluated in this study. In this direction the results from three short fibres sensors (coated with adhesive, coated without adhesive, and uncoated with adhesive) were collected. The results were compared to each other and to strain values from electrical strain gauge. The results revealed superiority of the short fibre with adhesive among all the sensors in sensitivity and accuracy including the strain gauge. The results of the short fibre were, then, compared to results of previous study long fibre. Again, the accuracy of the short fibre sensor was higher than that of the long fibre (deviation of 3% and 12% errors, respectively). In terms of sensitivity, the sensitivity of the short fibre was about 30% of the long fibre. However, sensitivities of both short and long fibres were in the nano-strain region (74 and 17 nano-stains respectively) and were much higher than electrical strain gauge (micro-strain range).