Effect of Impression Technique and Operator Experience on Impression Time and Operator-Reported Outcomes

Abstract

Purpose: To investigate the effect of impression technique (conventional preliminary alginate and digital scan) and operator experience in impression making (experienced in digital and conventional, experienced in conventional and inexperienced in digital, and inexperienced in conventional and digital) on impression time, satisfaction and stress levels, and the preference of the operators.

Material and methods: One patient was assigned for each of the 60 operators, who were experienced in impression techniques at different levels (Group 1: experienced in conventional and digital, Group 2: experienced in conventional and inexperienced in digital, Group 3: inexperienced in conventional and digital). They made conventional impressions (irreversible hydrocolloid) and digital scans (Trios 3) from the same patient. The impression times were recorded at each step (patient registration, maxillary arch, mandibular arch, and bite registration) and in total. A visual analog scale (VAS) was used for the operator satisfaction for applicability, comfort, and hygiene; the State-Trait Anxiety Inventory form (STAI-TX1) was used for stress, and a questionnaire was completed to measure the operator's impression preference. The data were analyzed with a 2-way ANOVA and Chi-square test (α = 0.05).

Results: A significant interaction was found between the operator experience in impression making and the impression technique on time for maxillary and mandibular arch impressions and total time (p ≤ 0.002). Operator experience and impression technique interaction had a significant effect on comfort and average VAS scores (p ≤ 0.016). Whereas, no significant effect of this interaction was found on stress (p ≥ 0.195). Operator experience in impression making had a significant effect on applicability (p < 0.001), and the impression technique had a significant effect on hygiene VAS scores (p < 0.001). Operators in Group 1 and Group 3 preferred the digital scans, however, operators in Group 2 had no preference (p = 0.022).

Conclusion: Operator experience in impression making and impression technique had varying effects on clinician's impression time, comfort, applicability, hygiene, and preference. Operators needed less time for the impressions they were experienced with. Operator stress level was not affected by the operator experience in impression making and the impression technique. Dental students and operators experienced in both techniques were satisfied with the digital scans and they preferred digital scans. Operators experienced with conventional impressions were satisfied with conventional impressions but didn't have a preference for the impression type.

Keywords: Impression; curriculum; dental students; intraoral scan; operator preference.