Rocking moments in extraction of teeth in the lower jaw

The purpose of this study was to observe, by means of strain gauges attached to forcep handles, the rocking moments needed during the extraction of lower jaw teeth. Great variation was found between the values for rocking moments and their acting times in different tooth groups. There were also great individual differences in the attachment of teeth. The mean value of the highest lingual rocking moments (2.80 J) was recorded during the extraction of first and second molars, and the highest labial moments (4.78J) during the extraction of canines. The mean value of the total rocking moments was highest during the extraction of canines (1.98 J) and lowest (1.19 J) during the extraction of premolars. The mean value of total rocking moments for incisors and canines was significantly lower (P less than 0.01) and for molars almost significantly lower (P less than 0.05) for the group aged 40 and over when compared to corresponding values for the group under 40 years of age. The lowest mean value of all extraction times was observed for incisors in all age groups.