title: How to design in situ studies: an evaluation of experimental protocols.
abstract: OBJECTIVE
  Designing in situ models for caries research is a demanding procedure, as both clinical and laboratory parameters need to be incorporated in a single study. This study aimed to construct an informative guideline for planning in situ models relevant to preexisting caries studies.
  
  
  METHODS
  An electronic literature search of the PubMed database was performed. A total 191 of full articles written in English were included and data were extracted from materials and methods. Multiple variables were analyzed in relation to the publication types, participant characteristics, specimen and appliance factors, and other conditions. Frequencies and percentages were displayed to summarize the data and the Pearson's chi-square test was used to assess a statistical significance (p < 0.05).
  
  
  RESULTS
  There were many parameters commonly included in the majority of in situ models such as inclusion criteria, sample sizes, sample allocation methods, tooth types, intraoral appliance types, sterilization methods, study periods, outcome measures, experimental interventions, etc. Interrelationships existed between the main research topics and some parameters (outcome measures and sample allocation methods) among the evaluated articles.
  
  
  CONCLUSIONS
  It will be possible to establish standardized in situ protocols according to the research topics. Furthermore, data collaboration from comparable studies would be enhanced by homogeneous study designs.
authors.affiliation: Department of Conservative Dentistry, Seoul National University School of Dentistry and Dental Research Institute, Seoul, Korea.
authors.forename: Young-Hye
authors.initials: YH
authors.lastname: Sung
authors.affiliation: Department of Dental Laboratory Science and Engineering, College of Health Science & Department of Public Health Science, Graduate School, Korea University, Seoul, Korea.
authors.forename: Hae-Young
authors.initials: HY
authors.lastname: Kim
authors.affiliation: Department of Conservative Dentistry, Seoul National University School of Dentistry and Dental Research Institute, Seoul, Korea.
authors.forename: Ho-Hyun
authors.initials: HH
authors.lastname: Son
authors.affiliation: Clinic for Persons with Disabilities, Seoul National University Dental Hospital, Seoul National University School of Dentistry and Dental Research Institute, Seoul, Korea.
authors.forename: Juhea
authors.initials: J
authors.lastname: Chang
keywords: Caries; Demineralization; Erosion; In situ; Materials and methods; Remineralization
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