title: Clinical Evaluation of Different Pre-impression Preparation Procedures of Dental Arch.
abstract: BACKGROUND
  Bubbles and voids on the occlusal surface impede the actual intercuspation and pre-impression preparation aims to reduce the incidence of air bubbles and voids as well as influences the quality of occlusal reproduction and actual clinical intercuspation in the articulator. The study was undertaken to determine the influence of different pre-impression preparation procedures of antagonistic dental arch on the quality of the occlusal reproduction of the teeth in irreversible hydrocolloid impressions and to determine most reliable pre-impression preparation method to reduce the incidence of air bubbles.
  
  
  METHODS
  A total of 20 subjects were selected having full complement of mandibular teeth from second molar to second molar with well demarcated cusp height. 200 impressions were made with irreversible hydrocolloid material. The impressions were divided into five groups of 40 impressions each and each group had one specific type of pre-impression preparation. All the impressions were poured in die stone. A stereomicroscope with graduated eyepiece was used to count the number of bubbles on the occlusal surface of premolars and molars. The mean and standard deviations were calculated for each group. Mann-Whitney U-test was applied to find the significant difference between different groups.
  
  
  RESULTS
  Least bubbles were found in the group in which oral cavity was dried by saliva ejector and fluid hydrocolloid was finger painted onto the occlusal surfaces immediately before the placement of impression tray in the mouth.
  
  
  CONCLUSIONS
  It was found that finger painting the tooth surfaces with fluid hydrocolloid immediately before the placement of loaded impression tray in the mouth was the most reliable method. The oral cavity can be cleared more easily of excess saliva by vacuum suction rather than by use of an astringent solution.
authors.affiliation: Reader, Department of Orthodontics and Dentofacial Orthopaedics, Manav Rachna Dental College, Faridabad, Haryana, India.
authors.forename: Nitin
authors.initials: N
authors.lastname: Arora
authors.affiliation: Reader, Department of Prosthodontics, Career Post Graduate Institute of Dental Sciences, Lucknow, Uttar Pradesh, India.
authors.forename: Monika
authors.initials: M
authors.lastname: Arora
authors.affiliation: Reader, Department of Prosthosontics, R.R. Dental College and Hospital, Udaipur, Rajasthan, India.
authors.forename: Naveen
authors.initials: N
authors.lastname: Gupta
authors.affiliation: Reader, Department of Prosthodontics, Vaidik Dental College and Research Centre, Daman, India.
authors.forename: Manisha
authors.initials: M
authors.lastname: Agarwal
authors.affiliation: Reader, Department of Orthodontics, Ideas Dental College, Gwalior, Madhya Pradesh, India.
authors.forename: Rohit
authors.initials: R
authors.lastname: Verma
authors.affiliation: Senior Lecturer, Department of Oral and Maxillofacial Surgery, PDM Dental College and Research Centre, Bahadurgarh, Haryana, India.
authors.forename: Pankaj
authors.initials: P
authors.lastname: Rathod
keywords: Antagonistic arch; air bubbles and voids; alginate; pre-impression preparation