Blalock et alClinical Implications Clinicians should instruct stamembers to closely monitor the time period that a vinyl polysiloxane impression material is in con- tact with disinectant solution, to prevent alteration othe wetting characteristics othe impression material and potential problems in obtaining a bubble-ree cast. Statement oproblem. Extended contact oimpression materials with chemical disinectant could remove suractant, signiicantly altering the contact angle and wettability characteristics oan impression material. Purpose. The purpose othis study was to determine the eect ocontact time ochemical disinectant solution on the dynamic contact angle oa commercial vinyl polysiloxsane impression material. Material and methods. Discs (3.5x25 mm) oheavy-body and wash consistencies omaterial (n=5) were abricated and either let untreated, or subjected to spray treatment with a commercial disinectant or various lengths otime (1, 20, or 60 minutes, or 24 hours). Treated specimens were washed and dried, ater which dynamic contact angle measurements oa water droplet were determined at various points in time ater deposition: 0, 2, 5, 10, 15, and 20 seconds. The same wash product was used without added suractant (control). For a given type oimpression mate- rial, contact angles were subjected to 1-way ANOV A within each droplet de position time or all periods odisinectantcontact (α=.05). The T ukey-Kramer post hoc test was app lied or pair wise means comparisons. Results. For each impression material type, signiicant increases in contact angles were ound as the duration odisin- ectant contact increased, at each measured droplet deposition time point. For both materials containing suractant, extended contact with chemical disinectant resulted in increased contact angles that were not signiicantly dierentrom those othe nonsuractant-containing control product. Conclusions. Increasing the contact time between a suractant-containing impression material and a disinecting solution can signiicantly alter the resulting contact angle othe impression material and render it similar to a mate- rial depleted osuractant. Following manuacturer-recommended chemical disinection times reduces suractant loss and only minimally aects surace wettability. ( J Prosthet Dent 2010;104:333-341) The effect of chlorine-based disinfectant on wet tabilit y of a vi nylpolysiloxane impression materialJohn S. Blaloc k, DMD, EdS, aJeril R. Cooper , DMD, b and Frederick A. Rueggeberg, DDS, MS c Medical College oGeorgia School oDentistry, Augusta, Ga Presented at the American Association oDental Research annual meeting, Washington, DC, March 3 through 6, 2010. a Associate Proessor, Department oGeneral Dentistr y. b Assistant Proessor , Depar tment oGeneral Dentistr y. c Proessor, D epartment oOral Rehabilitation. Impression materials must be dis- inected subsequent to removal rom the patient’s mouth and prior to being poured or casts. 1,2 Suractants (soap- like materials that provide enhanced wetting ohydrophobic suraces byaqueous luids) are added to some impression materials to provide bet- ter wetting ooral tissues and to en- hance coverage with unset stone, thus decreasing the occurrence obubbles in deinitive casts. 3-5 Exposure othe set impression material to a liquid disinectant may remove the surac- tant, rendering the impression surace more hydrophobic and creating prob- lems in obtaining bubble-ree deini- tive casts. One othe most commonly used synthetic elastomer impression mate- rials is vinyl polysiloxane (VPS). 6 This
