The computer-controlled local anesthetic injector Calaject®, (Rønvig Dental MFG, Daugaard, Denmark), which is designed to reduce the pain of performing local anaesthesia. The principle of this device is based on the fact that the less pressure and flow of a local anaesthetic injection, the less painful will be the procedure. Each device has an installed pressure sensor as well as a three-button display that allows choosing the most appropriate program in terms of different speeds and pressure. According to the anaesthesia technique, the manufacture recommends program I for intraligamentary and palatally injections, program II for infiltration and III for alveolar nerve block techniques. Conventional carpules and needles can be used in a pen-shaped part connecting to the main unit. The administration of the anaesthetic can be achieved using a foot control pedal which is adapted to the main unit, the speed of injection is related to acoustic signals.

Self-reported pain intensity on puncture using visual analogue scale (0 = no pain- 10 = the worse pain)

Self-reported pain intensity during delivery of the anaesthetic solution sing visual analogue scale (0 = no pain- 10 = the worse pain)

Assessed by the Dental Anxiety Scale (DAS)- Four questions survey with five possible answers. Each answer has a score: a = 1, b = 2, c = 3, d = 4, e = 5 Total possible = 20. Anxiety rating: 9 - 12 = moderate anxiety/ 13 - 14 = high anxiety/ 15 - 20 = severe anxiety