3D cone-beam C.T. imaging used to determine the effect of disinfection protocols on the dimensional stability of full arch impressions

Abstract

Aim: This study aimed to investigate the dimensional stability of irreversible hydrocolloid and polyvinylsiloxane (P.V.S.) impressions after exposure to four commercial disinfectants using cone-beam computed tomography (CBCT).

Materials and methods: Two different impression materials were tested: irreversible hydrocolloid and P.V.S. Four disinfection solutions were applied: BirexSE, Opti-Cide3, COEfect MinuteSpray, and CaviCide Spray. Distilled water was used as a control group. Each solution remained in contact with the impression for 5 min. Additional contact time of 5 min compromises time for scanning. The materials were evaluated for dimensional stability after the impression of a maxillary complete edentulous template via CBCT before and after being in contact with the disinfectant agents. Measurements were assessed on the digital models from A-B, B-C, and C-A points. Paired analyses (Wilcoxon Signed Rank test or paired Student's t-test) were used to analyze each measurement before and after the contact with the disinfectant agents. The variance for each measurement was also analyzed via a one-way analysis of variance or Kruskal-Wallis.

Results: Overall, there were no statistical differences among the points measurements in the irreversible hydrocolloid or P.V.S. between initial and final assessments (p > 0.05). The used disinfectant agents in this study did not influence each measurement's variation on irreversible hydrocolloid or P.V.S. (p > 0.05). All agents showed an effect on the dimensional stability of both impression materials. The differences in the three dimensions ranged between 0.34 and 1.54%.

Conclusion: Within 10 min of removing the impression from the master cast, is study's findings indicated that the four commercially available disinfectants did not influence the dimensional stability of irreversible hydrocolloid or P.V.S. Further studies should be performed to elucidate the antimicrobial effect of these solutions applied as a spray on the surface of irreversible hydrocolloid and P.V.S. impressions.

Keywords: Dental materials; Impression materials; Infection control; Irreversible hydrocolloid; Polyvinyl siloxane.

Fig. 1

Scheme of the study design.

Fig. 2

Preparation of impressions and dimensional stability assessment. Image “a” displays the template used to prepare the impression, indicating that it had three metallic equidistant reference points with 2 mm height each one. Image “b” shows the disposable trays used to obtain the specimens. Image “c” illustrates an impression material been scanned via CBCT. Image “d” demonstrates that the negative impression of the reference points of the template was changed to positive in the images to produce the final digital model.

Fig. 3

Results of the A-B, B-C, and A-C measurement for the impressions performed with irreversible hydrocolloid. The results were acquired before (initial) and after (final) and disinfection procedure.

Fig. 4

Results of the A-B, B-C, and A-C measurement for the impressions performed with P.V.S. The results were acquired before (initial) and after (final) and disinfection procedure.