impression techniques
TRANSCRIPT
IMPRESSION TECHNIQUESFOR IMPLANT PROSTHESES
AAMIR GODIL FIRST YEAR P.G.
DEPARTMENT OF PROSTHODONTICSM.A.R.D.C.
OUTLINE
• INTRODUCTION• MATERIALS REQUIRED• IMPRESSION TECHNIQUES• GINGIVAL MASKING• ERRORS• LITERATURE REVIEW• CONCLUSION
INTRODUCTION• Accurate recording of spatial implant position is required to obtain a proper
support to definitive restoration with passive fitting. Conrad et al (2007)
Implants V/S Crowns and Bridges
• It is more critical to record 3- dimensional position of the implants as they occur intraorally.
• Natural teeth have a PDL to compensate for minor inaccuracies while implants have not.
Pesun IJ (1997)
WHY SHOULD YOU MAKE IMPLANT IMPRESSIONS?
Position Depth
Axis(Angulation)
Soft Tissue Contour (Emergence Profile)
WHAT ALL DO YOU NEED TO MAKE IMPLANT
IMPRESSIONS?
WHICH IMPRESSION MATERIAL TO CHOOSE?
•Least stable •Low tear strength•Least desirable to use due to limitations of material
•Toxic to bone•Very rigid•Very Stable•Most hydrophilic
•Toxic to bone•Relatively Stable•Slow set•Unpleasant taste to patient
•Minor bone toxicity•Very stable•Multiple viscosities available POLY
VINYL SILOXAN
EPOLY-
SULFIDE
OTHERS (HYDRO-COLLOID
S)
POLY-ETHER
HOW TO MAKE AN IMPRESSION FOR IMPLANT
PROSTHESES?
Implant Level Impressions1. Pick Up (Open Tray) 2. Transfer Type (Close Tray )
Abutment Level Impressions 1. Direct Technique 2. Indirect Technique
IMPLANT LEVEL IMPRESSIONS
Open TrayMore accurate for multi unit
impressionsIn cases with implant/abutment
angulations and path of insertion withdrawal Less accurate for
multi unit cases
Closed TrayLess accurate for multi unit
impressions
IMPLANT LEVEL IMPRESSION TECHNIQUES
CLOSED TRAY IMPRESSION TECHNIQUE
IndicationsLiou Ad (1993)
•Limited inter arch space•Tendency to gag •Difficult access in the posterior region of the mouth
AdvantagesConrad H. (2007)
•Easier •Suitable for short inter arch distance•Visual fastening of the analog to the coping is more accurate
DisadvantagesConrad H. (2007)
•Inaccuracies with recovery and subsequent deformation of impression material may be encountered with nonparallel implants•Not suitable for deeply placed implants
SPLINTING FOR MULTIPLE IMPLANT IMPRESSION• The common practice of joining the direct transfer copings with acrylic resin
is an attempt to – stabilize the copings against rotation during fixture or abutment analog fastening – control the relationship between implants in a rigid fashion
(Spector MR, Donovan TE, Nicholls JI. An evaluation of impression techniques for osseointegrated implants.J Prosthet Dent 1990;63:444–447)
• Assif et al. and Naconecy et al. showed that splinting technique was significantly more accurate than unsplinted techniques
(Assif D, Marshak B, Schmidt A. Accuracy of implant impression techniques. Int J Oral Maxillofac Implants 1996;11:216–222)(Naconecy MM, Teixeira ER, Shinkai RS, Frasca LC, Cervieri A. Evaluation of the accuracy of 3 transfer techniques for
implant-supported prostheses with multiple abutments. Int J Oral Maxillofac Implants 2004;19:192–198)
OPEN TRAY IMPRESSION TECHNIQUE
STEPS IN SPLINTING MULTIPLE IMPLANTS FOR IMPRESSION
1. Autopolymerising resin (sectioned and reconnected)
2. Impression Plaster (PI) and Polyether (FI)
2. Impression Plaster
3. Autopolymersing resin at the time of impression
3. VPS bite registration material
J Adv Prosthodont. 2011 Dec;3(4):177-85
ALL ON SIX
Indications
•Multiple implants•Very closely located implants
AdvantagesHeather J.
•Reduces the effect of the implant angulation•Reduces the deformation of the impression material•Removes the concern for replacing the coping back into its respective space in the impression.
DisadvantagesHeather J.
•Some rotational movement of the impression coping when securing the implant analog may occur•Blind attachment of the implant analog to the impression coping may result in a misfit of components
ABUTMENT LEVEL IMPRESSIONSSimple
provisional restoration fabrication
For custom-made
abutments
Selecting abutments in the laboratory
DIRECT- ABUTMENT LEVELIMPRESSION TECHNIQUE
INDIRECT- ABUTMENT LEVEL IMPRESSION TECHNIQUE
GINGIVAL MASKING
WHAT SHOULD YOU SEND TO THE LAB?
Lab prescription
Detailed with all required
prosthetic design and
case details.
Appropriate and accurate impressions
Implant level
Abutment level
Mounted models
Preoperative
Diagnostic wax up
Necessary restorative components for
implant
Temporary abutments
Impression analog
Implant analog
Necessary abutment screws
WHAT ARE THE PROBABLE ERRORS?HOW DO YOU MINIMIZE THEM?
VERIFY THE SEATING OF COMPONENTS
IMPROPER INTERFACE BETWEEN
IMPRESSION POST AND IMPLANT
ANALOGUE
ERRORS IN IMPRESSION
MAKING• Latex gloves with PVS impression material• Non-uniform thickness of material
LITERATURE REVIEW
Three-Dimensional Accuracy of Implantand Abutment Level Impression Techniques:
Effect on Marginal Discrepancy
With comparison of different impression methods, including abutment level and implant level (closed tray and open tray), no
significant difference was noted
Journal of Oral Implantology
CONCLUSION
• Precise impression methodology would decrease the failures related to the supra structure fabrication
Ozkane, 2006
• Imprecise superstructure fit results in mechanical and biologic consequences that disrupt the function of dental implants
Heather J. et al, 2007
Thank You