Comparison of digital intraoral scanners and alginate impressions: Time and patient satisfaction

Am J Orthod Dentofacial Orthop. 2018 Apr;153(4):534-541. doi: 10.1016/j.ajodo.2017.08.017.


Introduction: Recent technological advances have made intraoral scans and digital models a possibility and a promising alternative to conventional alginate impressions. Several factors should be examined when considering an intraoral scanner, including patient acceptance and efficiency. The objectives of this study were to assess and compare patient satisfaction and time required between 2 intraoral scanners and conventional alginate impressions.

Methods: An initial pilot study was completed to create a valid and reliable survey instrument that would measure 3 areas of patient satisfaction with the impression experience. A visual analog scale survey was developed and administered to 180 orthodontic patients receiving 1 of 3 types of impressions: (1) iTero Element intraoral scan (Align Technologies, San Jose, Calif), n = 60; (2) TRIOS Color intraoral scan (3Shape, Copenhagen, Denmark), n = 60; and (3) conventional alginate impression (imprEssix Color Change; Dentsply Sirona, York, Pa), n = 60, and the time required to obtain the impressions was recorded.

Results: Reliability was evaluated with intraclass correlation coefficient values for 17 paired questionnaires, and all questions were found to be reliable (intraclass correlation coefficient, ≥0.65). For the main study, 180 subjects completed timed impressions and surveys. Data indicated that subjects receiving intraoral scans preferred the digital impressions, and subjects receiving alginate impressions were neutral regarding impression preference, and that efficiency varied based on the impression method.

Conclusions: Intraoral scanners are accepted by orthodontic patients, and they have comparable efficiency with conventional impression methods depending on the type of scanner.

MeSH terms

  • Adolescent
  • Adult
  • Alginates*
  • Child
  • Computer-Aided Design
  • Dental Impression Materials
  • Dental Impression Technique / instrumentation*
  • Dental Models
  • Female
  • Glucuronic Acid
  • Hexuronic Acids
  • Humans
  • Image Processing, Computer-Assisted / instrumentation*
  • Imaging, Three-Dimensional / instrumentation
  • Male
  • Middle Aged
  • Orthodontics
  • Patient Satisfaction*
  • Pilot Projects
  • Reproducibility of Results
  • Surveys and Questionnaires
  • Time Perception*
  • Young Adult


  • Alginates
  • Dental Impression Materials
  • Hexuronic Acids
  • Glucuronic Acid