{'fraction_non_alphanumeric': 0.03825136612021858, 'fraction_numerical': 0.02622950819672131, 'mean_word_length': 5.144295302013423, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Evaluation of different impression techniques for indirect E-max fixed dental prostheses. Randomized clinical trial

Background: Assessment of optical in comparison to traditional impressions is needed. The goal of this research is evaluating optical and traditional impressions regarding time, participant, and operators' preference. Materials and Methods: One optical and two traditional impressions were made in ten participants randomly. Optical scanner used is Omnicam of Cerec; traditional impression used closed mouth tray and other used one-step traditional tray. Time taking impression and occlusal relationship registration were evaluated. Participants and operators feeling about easiness of procedure were evaluated using visual analog scales. Paired t-test was applied detecting differences. Results: Mean time ± standard deviation was 336 ± 9.4 s using traditional closed mouth technique, 557 ± 8.2 for single step, and 397 ± 8.6 s for Omnicam. Timing of closed mouth technique was significantly lower than single-step and optical impression. Participant's assessment (very uncomfortable = 0 and comfortable = 100) measured 68 ± 9.7 for closed mouth, 79 ± 9.4 for optical, and 59 ± 9.7 for the single-step technique. There was statistical significance between differences except between closed mouth and single-step techniques; differences between them were not significant. Operators assessment (simple = 0 and very difficult = 100) was 21 ± 9.5 for closed mouth, 62 ± 9.2 for optical, and 46 ± 11.2 for single-step technique. There was statistical significance between the differences. Conclusions: Closed mouth took less time than optical and the single-step technique. Regarding comfort of participant, optical impression was the best. Operator's assessment favored optical impressions most as being the easiest.