CLINICAL PRACTICE
" DOUBLE STEP REVERSE ” ( DSR ): A NEW PROTOCOL IN POLYVINYLSILOXANES ( PVS ) IMPRESSION-TAKING PROCESS - TWO CASE REPORTS
Enrico Manca 1a * , Marco Fazio 2b , Riccardo Aiuto 2c , Giacomo Derchi 1 , 3d
1
Department of Surgical Pathology , Medicine , Molecular and Critical Area , University of Pisa , Pisa , Italy
2
Private Dental Practice
3
Tuscan Stomatologic Institute , Lido di Camaiore , Italy a
DDS , Professor in University Master Degree in Oral Implantology , Clinical Dentist in Cagliari ( Italy ) b
DDS , Clinical Dentist in Palermo ( Italy ) c
DDS , Clinical Dentist in Milano ( Italy ) d
DDS , MSc , PhD , Assistant Professor , Clinical and Research Fellow
Received : July 09 , 2016 Accepted : July 11 , 2016
Available online : September 12 , 2016
Cite this article : Manca E , Fazio M , Aiuto R , Derchi G . “ Double Step Reverse ” ( DSR ): a new protocol in polyvinylsiloxanes ( PVS ) impression-taking process - two case reports . Stoma Edu J . 2016 ; 3 ( 2 ): 184-192 .
ABSTRACT
Aim The aim of this case report is to describe a new protocol which can be useful to the clinician and can lead to a less frustrating process while taking dental impressions for fixed prosthodontics . Summary With the “ Double-Step Reverse ” technique it is shown that it is easier to take excellent impressions , especially in the post-space and in the multiple preparation impressions , without worrying about V-shaped voids and bubbles on the finishing line . Key learning points The DSR protocol requires that the wash material ( Aquasil Ultimate ) is first delivered on preparations , then we wait for its complete setting and later we deliver the tray material , with an impression tray . The DSR technique allows greater patient cooperation and greater serenity during the 3 minutes of the setting time . It is time-saving and reduces the waste of polyvinylsiloxanes ( PVS ) materials . Keywords : prosthetic dentistry , PVS impressions , accuracy , dental materials , double-step impressions .
1 . Introductions The impression-taking process has always been a delicate step in fixed and removable prosthodontics ; several techniques and materials have been evaluated with varying degrees of success . The scientific papers provide us with comparisons between different impression techniques and different materials , so it is hard to find a unique agreement . On the other hand , the dental supplies offer many types of hydrocolloid materials , polyether , polysulfide and polyvinylsiloxanes ( PVS ). The importance of the quality of a dental impression is well known and it is shown by many articles that compare not only the available materials 1-2-3 , but also the impression techniques 4-5 . Material and technique are not the only factors that affect the accuracy of impression . In 2004 Perakis , Belser , Magne 6-7 , in a review , considered , among other things , the rheology of materials , remembering the three phases of process : 1 ) Viscous phase which allows mixing and handling ; 2 ) Plastic phase for the adaptation to the anatomy of the mouth ; 3 ) Elastic phase that allows the removal of the material overcoming any undercuts . The authors pointed out that polyvinylsiloxanes ( PVS ) move rapidly from a viscous to an elastic phase , then requiring a short working time after mixing . Thus , compared to polyether ( PE ), PVS have a shorter plastic phase . On the other hand , the rigidity of the PE , twice as double the PVS , often makes the disconnection difficult . These data are confirmed by the work of McCabe in 1998 8 . A brand new PVS , coupled with a handpiece that is attached to the turbine hose , mixes and dispenses the wash material under pressure . Thanks to the characteristics of this new PVS and method of application it is possible to apply the wash material on preparations , then wait for its complete polymerization and later on the tray material is applied . This is called the new Double Step Reverse technique ( DSR ). The purpose of this paper is to show a new protocol to take impressions in polyvinylsiloxanes ( PVS )
* Corresponding author :
Dr . Enrico Manca , DDS , Studio Enrico Manca , Via Giovanni Battista Tuveri , 108 , I-09129 Cagliari , Italy Tel / Fax : 070-485-337 ; e-mail : infostudiomanca70 @ gmail . com
184 STOMA . EDUJ ( 2016 ) 3 ( 2 )