Table 1 The torque angle values at the 0.5-mm increments and at the inflection point of the incisor in Figs. 1 and 2 are shown in this table. As the palatal CEJ of this incisor is located at the x coordinate point 7.70, the most cervical 0.5-mm increment is [P₁ + 7.50]. Incremental subtractions were calculated for the successive 0.5-mm increments in the incisor part incisal to the inflection point and in the incisor part cervical to the inflection point. An incisor part containing an X number of 0.5-mm increments contains a number equal to X − 1 of incremental subtractions. Note the progressive decrease in torque angle values of the increments from P₁ to inflection point and the opposite progressive increase in the torque angle values of the increments from inflection point to the most cervical calculated increment. An incremental subtraction had a negative value in the incisor part incisal to inflection point and a positive value in the incisor part cervical to it. The inflection point had the most negative torque angle value on PSC

From: The inflection point: a torque reference for lingual bracket positioning on the palatal surface curvature of the maxillary central incisor