RESUMEN
This case study explored how human-centred design methodologies can improve clinician experience and reduce patient treatment anxiety in the application of a new dental local anaesthetic jet-injection system. An initial embodiment of the prototype injector, dubbed the 'Kiwi' injector, was developed to better understand the user experience during dental-injection procedures. Further design development was undertaken in two distinct phases. Stage one entailed the initial non-functional Kiwi injector model being used as a design probe to explore clinician views on its aesthetics and ergonomics. The second stage explored the clinician and patient experiences of the functional Kiwi Injector while administering a local anaesthetic to the patient. Stage one findings highlighted clinician satisfaction with the aesthetics of the non-functional prototype device but expressed the desire to make the device smaller. Stage two clinical study results highlighted an issue with the functional jet injector configuration, where the participating dental clinicians speculated that a greater bend in the wand and change of trigger position would significantly improve the Kiwi injector ergonomic performance. This research has demonstrated the benefits of applying a structured and staged human-centred user experience design process to inform the design of a new dental anaesthetic delivery device.
RESUMEN
OBJECTIVES: We evaluated patient preference and reported levels of anxiety and discomfort of participants treated with a new needle-free electric motor-driven device vs. conventional local anaesthetic for dental extractions in a proof-of-principle study. Healing and response of gingival tissues to injection were also evaluated at 1, 3- and 7-days post-procedure. METHODS: After informed consent, eight participants who required bilateral maxillary extractions were included in the trial. The side and order of placement for the needle-free and conventional anaesthetic were randomized. The same operator delivered anaesthesia and ensured teeth were anaesthetized on both sides. Another operator, unaware of order and type of anaesthesia placed, performed the extractions. RESULTS: Participant's average discomfort scores were low for both techniques, and lower for the needle-free injection at all timepoints. Needle-free local anaesthesia was the preferred technique by most participants at most timepoints. The average volume of anaesthetic dispensed was similar between techniques. Successful anaesthesia with the needle-free device was achieved in 6 out of 8 participants. Healing of the extraction sockets and adjacent oral mucosa progressed normally for all participants, with no evidence of infection, trauma or hematoma in the injection sites of the test and conventional sides. CONCLUSIONS: The needle-free local anaesthetic technique investigated achieved sufficient anaesthesia for tooth extractions in the maxilla in 75% of the subjects. A larger clinical trial is needed to further validate the technique tested and to investigate whether needle-free local anaesthesia can be successfully applied to the provision of restorative therapy. CLINICAL SIGNIFICANCE: The results of this study can be used by clinicians treating patients who suffer from dental anxiety and needle-phobia.