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Implant impressions- journal club - Accuracy of implant impressions using various impression techniques and impression materials

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Partha Sarathi Adhya
Partha Sarathi Adhya

This journal club deals with different impression techniques for implant restorations. These include two different impression techniques using different impression materials.

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UNDER THE ABLE GUIDANCE OF: PROF(DR.) JAYANTA BHATTACHARYYA(HOD & PRINCIPAL) PROF(DR.) SAMIRAN DAS PROF(DR.) SOUMITRA GHOSH DR. SAYAN MAJUMDAR PROF (DR.) PREETI GOEL Presented by- Partha Sarathi Adhya. (3rd year PGT)  Accuracy of implant impressions using various impression techniques and impression materials  Y Ravi Shankar, Sibeka Sahoo, M Hari Krishna, P Shameen Kumar, T Satyendra Kumar.  J Dent Implant 2016;6:29-36.
 Impression making for the implant is one of the important factor to obtain a good prosthesis. A good implant impression records three dimensional position of implant in oral cavity. An accurate impression is mandatory for the success of implant supported dental prosthesis as an accurate recording of spatial implant position is required to obtain a proper support to definitive restoration with passive fit.
 Fixture level or implant level impression-  In this technique position, angulation , orientation to the soft tissue margin of the implant is recorded and abutment is selected accordingly.  Impression copings are used in this technique which are positioned sub gingivally. Prasad DK, Prasad DA, Colaco C. Beyond osseointegration: Clearing the prosthetic dilemma. Indian Journal of Oral Sciences.2016 Jan 1;7(1):11.
 Open tray impression technique-  Custom/ stock tray with hole in the implant coping areas is used.  Multiple implant cases.  Implant with severe angulation.  Implants with different angulation.  Reduces the effect of implant angulation, deforming the impression material upon recovery from mouth.  Splinting of the transfer copings prevents rotational movement of impression copings in the impression material during analog fastening.
 Transfer Type / Close Tray Technique  the impression copings remain in the mouth on the removal of the set impressions. After the removal of the impression, the impression copings are transferred to the impressions and then the cast is poured.  Limited inter arch space  Tendency to gag  Difficult access in the posterior region of the mouth  Easier  Suitable for short inter arch distance.  Visual fastening of the analog to the coping is more accurate  Inaccuracies with recovery and subsequent deformation of impression material may be encountered with nonparallel implants.  Not Suitable for deeply placed implants Chee W, Jivraj S. Impression techniques for implant dentistry. British dental journal. 2006 Oct;201(7):429.
 Abutment level impression  In this technique the position, orientation of the abutment is recorded.  Indirect Impression Technique  The indirect impression technique is a method of making an impression by first connecting the abutments to the implant fixture and subsequently connecting the impression copings to them.  In this technique plastic or snap fit impression technique is used.
 Direct Impression Technique-  The direct impression technique involves screwing of the final abutment into the implant in the oral cavity followed by its preparation within the mouth itself using rotary instruments.  Less time consuming  Margins can be prepared according to operators specifications  Single appointment procedure.
IMPRESSION MATERIALS 1. Polyvinylsiloxane. 2. Polyether. 3. Vinyl Polyether Siloxane compound developed by combining polyether polymer and vinyl groups of VPS . • Total setting time 2-3 min , Working time 2 min. • Better wettability. The lowest achievable contact angle ,less than 10° after 1 second. • The vinyl siloxane ethers have a dimensional change of ≈ –0.2% . • Hardness (Shore) ≈ A45- 60 . Shetty RM, Bhandari GR, Mehta D. Vinyl Polysiloxane Ether: A Breakthrough in Elastomeric Impression Material. World. 2014 Apr;5(2):134-7.
Splinting material for implant impression • Pattern resin. • Flowable composite. • Bite registration paste. • Less polymerization shrinkage. (3%-5%). • Less heat generation. • Less setting time (3-5 min). • More polymerization shrinkage. (7-12%). • More permanent deformation. • No heat generation. • More permanent deformation. Joseph TM, Ravichandran R, Lylajam S, Viswabharan P, Janardhanan K, Rajeev S. Evaluation of positional accuracy in multiple implants using four different splinting materials: An in vitro study. The Journal of Indian Prosthodontic Society. 2018 Jul 1;18(3):239.
Aim- to investigate the accuracy of master cast using two impression techniques, i.e. open and closed tray techniques .  To evaluate the accuracy of impression materials including PVS(polyvinylsiloxane), PE(polyether ), and VSE(Vinylsiloxanether) .  To evaluate the effect of splinting and nonsplinting methods and angulations of implants in them.  A U-shaped stainless steel die framework (12 mm × 10 mm × 50 mm) simulating the edentulous mandible fabricated.  Six holes were drilled to a depth of 10 mm and diameter of 4.3 mm with the help of 3D computerized numerical control universal vertical milling machine.  The lab analogs (4.2 mm diameter) were positioned in different angulations and assigned as A, B, R, C, D, and E, the center analogs R . Article Proper
 The analogs B and D were placed at an angle of 10° and the analogs A and E were positioned at 20° to the center axis with respect to center analogs.  Six orientation marks were drilled, i.e. three labially and three lingually which were 2 mm wide and 1 mm deep.  Sixty custom impression trays were made with autopolymerizing methacrylate resin with spacer thickness of 3 wax sheet.  The impression trays for open tray technique had six windows to allow access for the copings screws  The impressions for open tray technique were divided primarily into splinted group and the nonsplinted group.  The splinted group was subdivided into two groups; (1) splinting with dental floss and pattern resin and (2) splinting with plastic rod.
• subgroup 1, putty index was fabricated at a level just below the grooves of the rectangular part of the impression coping to act as a Scaffold. • Pattern resin (GC ASIA Dental PTE. Ltd.,) was mixed and adapted to surround the copings and dental floss with paintbrush. • The pattern resin was sectioned in the center to create a gap of 0.2 mm between the sectioned parts Impressions were made using three elastomeric impression materials. 1. PVS (Dentsply, medium-bodied) which was mixed in a base and catalyst ratio of 1:1 2. PE (3M ESPE, medium-bodied) in the ratio of 7:1 3. Vinylpolysiloxanether (Identium, medium-bodied) in the ratio of 5:1. subgroup 2, the stirrer was sectioned to fit into the space and was secured to copings with the help of pattern resin .
 Impressions were made, and following the setting of the material, analogs were fixed to the copings and casts were poured with Type IV die stone.  The experimental casts were measured in three axes with coordinate measuring machine  The reference point taken for all the measurements was analog R which was perpendicular to the surface of the cast.  The distances in X axis were termed as XA, XB, XC, XD, and XE. The distances in Y axis were designated as YA, YB, YC, YD, and YE. Similarly, for Z axis, it was ZA, ZB, ZC, ZD, and ZE.  The mean and standard deviation of the differences in inter implant distances (IIDs).
Parameter PVS PE VSE Dev X 29.40 27.80 24.20 Dev Y 64.40 55.40 48.60 Dev Z 22.60 26.40 16.60 Dev 3D 42,255.80 42,246.80 42,239.80 Dev angle 0.40 0.40 0.20 Dev IID 143.60 127.40 122.80 Parameter PVS PE VSE Dev X 28.40 26.20 24.60 Dev Y 61.60 52.60 43.60 Dev Z 18.80 23.20 16.80 Dev 3D 42,252.80 42,244.20 42,234.60 Dev angle 0.00 0.20 0.40 Dev IID 136.40 122.60 120.60 Results-
Parameter PVS PE VSE Dev X 59.40 54.60 44.60 Dev Y 99.40 85.40 71.80 Dev Z 50.40 44.40 36.40 Dev 3D 42,291.80 42,277.60 42,263.80 Dev angle 0.60 0.80 0.60 Dev IID 208.40 148.20 139.60
 It is reported that angular positional transfer deformation increases with an increase in an implant’s buccal/ lingual inclination with respect to horizontal crestal plane.  An angulation of 20° and rotational freedom of 1.5° can result in a horizontal misfit up to 127 microns.  In clinical situation, the submandibular fossa mandates implant placement with increasing angulation as it progresses distally. Therefore, in the second premolar region, angulation may be 10° to horizontal plane; in the first molar area, 10–15°; and in the second molar region, 20–25°.  In this study, monophase technique was used as it is accomplished in a single-step procedure using materials with a medium viscosity to allow the material itself to record finer details while avoiding the slumping of the material in the tray, less time-consuming, and simple to perform.  the impression coping remains in the impression, the open tray technique reduces the effect of implant angulation, deforming the impression material upon recovery from mouth, and removes the concern of replacing the copings into the impression. Discussion-
 The underlying principle of splinting the impression copings is to connect them together using a rigid material to prevent individual coping movement during the impression making procedure.  The greater deviation with stirrer and resin splint could be attributed to the relative flexibility of the plastic rod compared to the floss and pattern resin.  Hydrophilicity, greater followability, better surface wettability of VSE may lead to accurate impression.  Better tear strength and rigidity of PE leads to more accurate impression than PVS.
1.The open tray technique was more accurate than the closed tray technique when multiple implants are considered 2. The VSE material showed lesser deviation from the reference die compared to PE and PVS. 3. Splinting of the impression copings had a significant effect on the accuracy of the casts. 4. Among the splinting methods used in the present study, splinting with dental floss and acrylic was more reliable than splinting with plastic rod and acrylic. 5. The relation between the angulation and impression material can be established that as with increase in angulation, the amount of forces of deformation increases which require an impression material which can withstand these forces that affect the accuracy of master cast. Conclusions
 Critical Evaluation-  Seating load of the impression trays.  Measurement of angular deviation and three dimensional deviation not mentioned.
 Comparative analysis of the accuracy of different direct impression techniques for multiple implants.  D Öngűl, B Gökçen-Röhlig, H Keskin.  Australian dental journal. 2012 Jun;57(2):184-9. Aim- evaluate the effect of splinting on implant impression accuracy when making impressions of edentulous arches containing multiple implants.  A reference model of an edentulous maxilla was produced with six Straumann Tissue Level implants.  Experimental Group 1 (EG1): Screw-on synOcta impression copings.  Experimental Group 2 (EG2): Screw-on synOcta impression copings splinted with acrylic resin bar (non-sectioned acrylic bar).  Experimental Group 3 (EG3): Screw-on synOcta impression copings splinted with two separate acrylic resin bars (sectioned acrylic bars). RELEVANT ARTICLES
 Experimental Group 4 (EG4): Screw-on synOcta impression copings splinted with light-curing composite resin bar (non- sectioned composite bar).  Experimental Group 5 (EG5): Screw-on synOcta impression copings splinted with two light-curing composite bars (sectioned composite bars).  Polyether impression material (Impregum Penta Soft, 3M ESPE Dental, Medizin, Germany) was used for all impressions.  Dimensional deviations were measured at predetermined points mesial, distal, vestibular and palatal to each implant, for a total of 24 points in each cast.
Group Mean Deviation EG1 24.10 EG2 12.70 EG3 22.71 EG4 23.70 EG5 41.09  The sectioned bars (EG3 and EG5) demonstrated more deviation from the master model than the non-sectioned bars.  Splinting of the impression copings should be the ideal method to increase the impression accuracy.  Acrylic resin is the ideal material for splinting.
 COMPARATIVE EVALUATION OF THE DIMENSIONAL ACCURACY OF CLOSED TRAY AND OPEN TRAY IMPRESSION TECHNIQUE.  Tandon A, Bulbule NS, Jagtap AK, Kakade DM.  Journal of Clinical & Diagnostic Research. 2017 Nov 1;12(11).. Aim-Evaluating and comparing the accuracy of closed tray to that open tray impression technique and also to compare two different elastomeric impression materials  Four internal connection implants (alfa dent), were placed in the acrylic resin model.  Closed tray : dentulous stock tray  30 : closed tray impression; 15+15 polyether & polyvinyl siloxane  The direct impression transfer copings were screwed into position over the implant fixtures and impressions were made.  Open tray  30 : open tray impression; 15+15 polyether & polyvinyl siloxane
 Impression copings were screwed and splinted using cold cure acrylic resin.
 The open-tray impression technique exhibited higher accuracy in comparison to closed-tray technique.  The difference in the accuracy of the impressions obtained using polyether and polyvinyl siloxane were not statistically significant.
 A comparative analysis of the accuracy of implant master casts fabricated from two different transfer impression techniques.  Rupali Patil, Pankaj Kadam, Seema Patil, Shweta Jajoo.  J Int Prevent Communit Dent 2016;6:142-8. Aim – to find the most accurate impression technique(open/close), along with understanding the influence of tray type (custom/stock) for transfer of intraoral position of implant fixtures on cast.  Edentulous maxillary resin model was made with four implants of Ø 4x 10 mm placed.  The distances between four implants of master models were measured using an optical microscope.  Four impression groups were formed as follows;  Group 1: Stock open tray (SOT) technique  Group 2: Stock closed tray (SCT) technique  Group 3: Custom open tray (COT) technique  Group 4: Custom closed tray (CCT) technique.
 All the impressions were stored for 24 h before pouring. Later, Type IV gypsum.  A calibrated optical microscope was used to record the positional accuracy of the implants. Groups A-B distanc e A-b B-C distanc e B-C C-D distanc e C-D A-D distanc e A-D SOT 7.36 mm 7.35 13.95 mm 13.85 8.15 mm 8.08 30.65 mm 30.72 SCT 7.26 13.82 8.16 30.79 COT 7.34 13.91 8.16 30.70 CCT 7.55 14.10 8.22 30.80
 The open tray impression technique is more accurate as compared to the closed tray technique.  COT shows the most accurate impression technique among all.
 Accuracy of various impression materials and methods for two implant systems: An effect size study.  Alexander Schmidt,Teresa Häusslinga, Peter Rehmanna, Heidrun Schaaf.  Journal of prosthodontic research. 2018;62(2):245-51 Aim-To determine the effect of the impression material/method (open or close tray), and implant angulation ( 0°, 15°,20°)on impression transfer precision.  An upper jaw model with three BEGO and three Straumann implants (angulations 0°, 15°, 20°) in the left and right maxilla was used as a reference model.  One polyether (Impregum Penta IP) and two polyvinylsiloxane (Flexitime Monophase FM/Aquasil Ultra Monophase AU) based materials were used as impression materials.  For the open tray technique impression copings were splinted and for closed tray impression plastic transfer caps were used.  For open tray technique custom impression tray was fabricated with holes in implant areas.
 For the measuring procedure, angled abutments with different angulations (0°, 15°, 20°) were placed on the respective angled implants.  A Rapid coordinate measurement machine was used to measure the target variables with respect to accuracy for the 3D shift.  IP1-Polyether Open tray.  IP2-Polyether Closed tray.  FM1-Polyvinyl siloxane Open tray.  FM2- Polyvinyl siloxane Closed tray.  AU1- Polyvinyl siloxane Open tray .  AU2-Polyvinyl siloxane Closed tray
 The impression method (open/closed tray) generated differences in the impression accuracy, with no significant difference.  Compared to polyether, polyvinyl siloxane materials showed the highest transfer accuracy, with significant difference in the 3D shift.  Implant system did not affect the accuracy of impression.
 A Comparison of implant impression precision: Different materials and techniques.  Mahtab Tabesh, Marzieh Alikhasi, Hakimeh Siadat.  J Clin Exp Dent. 2018;10(2):e151-7 Aim-to compare polyvinyl siloxane, polyether and vinyl siloxanether impressions with two techniques of direct and indirect impression making in terms of precision.  A master model of edentulous maxilla was constructed includingFour implants of Ø 4.3 x 11 mm .  Anterior two implants were parallel to each other and perpendicular to edentulous ridge while posterior ones were tilted 45° distally.  Seventy two 2mmthick custom trays (36 open and 36 closed trays) were fabricated. Impession wee taken using polyether (PE), polyvinyl siloxane (PVS), and vinyl siloxanether (VSE) materials.
 For each implant on the casts, the x, y and z coordinates were measured by recording the distances from the reference point on the center of the superior surface of the reference cylinder to center of the implant in each dimension. x (mm) y (mm) z (mm) r (mm) Polyvinyl Siloxane 0.133 .101 .232 .314 0.179 .138 .599 .683 Polyether .089 .069 .148 .206 .143 .120 .180 .306 Vinyl Siloxanether .117 .105 .199 .294 .155 .086 .252 .335
 For closed technique is considered polyether is the better choice.  For open technique polyether and vinyl siloxanether are choices. If vinyl siloxanether is the material, then both open and closed techniques are favorable.
 Digital vs. conventional full-arch implant impressions: a comparative study  Sarah Amin,Hans Peter Weber,Matthew Finkelman,Khaled El Rafie.  Clinical oral implants research. 2017 Nov;28(11):1360-7. Aim-To test whether or not digital full-arch implant impressions with two different intra-oral scanners (CEREC Omnicam and True Definition) have the same accuracy as conventional ones.  A stone master cast representing an edentulous mandible using five internal connection implant was fabricated.  The three median implants were parallel to each other, the far left implant had 10°, and the far right had 15° distal angulation.  splinted open-tray technique was used for the conventional polyether impressions (n = 10) for Group 1. Digital impressions (n = 10) were taken with two intraoral optical scanners (CEREC Omnicam and 3M True Definition) after connecting polymer scan bodies to the master cast for groups 2 and 3.
 Master cast and conventional impression test casts were digitized with a high-resolution reference to obtain digital files. Digital full-arch implant impressions using True Definition scanner and Omnicam were significantly more accurate (trueness) than the conventional impressions
 Conclusions-  The impression of implants has several differences compared to the impression of natural teeth and the clinician should take these differences under consideration. Careful selection of the proper impression material and technique according to the needs of each clinical case is of vital importance to achieve the construction of an accurate working cast.
 Bibliography • Amin S, Weber HP, Finkelman M, El Rafie K, Kudara Y, Papaspyridakos P. Digital vs. conventional full‐arch implant impressions: a comparative study. Clinical oral implants research. 2017 Nov;28(11):1360-7. • Patil PS. A comparative analysis of the accuracy of implant master casts constructedd from two different transfer impression techniques-an in vitro study. • Tabesh M, Alikhasi M, Siadat H. A comparison of implant impression precision: Different materials and techniques. Journal of clinical and experimental dentistry. 2018 Feb;10(2):e151. • Schmidt A, Häussling T, Rehmann P, Schaaf H, Wöstmann B. Accuracy of various impression materials and methods for two implant systems: An effect size study. Journal of prosthodontic research. 2018;62(2):245-51. • Prasad DK, Prasad DA, Colaco C. Beyond osseointegration: Clearing the prosthetic dilemma. Indian Journal of Oral Sciences. 2016 Jan 1;7(1):11. • Chee W, Jivraj S. Impression techniques for implant dentistry. British dental journal. 2006 Oct;201(7):429. • Shankar YR, Sahoo S, Krishna MH, Kumar PS, Kumar TS, Narula S. Accuracy of implant impressions using various impression techniques and impression materials. Journal of Dental Implants. 2016 Jan 1;6(1):29.
Implant impressions- journal club - Accuracy of implant impressions using various impression techniques and impression materials

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Implant impressions- journal club - Accuracy of implant impressions using various impression techniques and impression materials

  • 1. UNDER THE ABLE GUIDANCE OF: PROF(DR.) JAYANTA BHATTACHARYYA(HOD & PRINCIPAL) PROF(DR.) SAMIRAN DAS PROF(DR.) SOUMITRA GHOSH DR. SAYAN MAJUMDAR PROF (DR.) PREETI GOEL Presented by- Partha Sarathi Adhya. (3rd year PGT)  Accuracy of implant impressions using various impression techniques and impression materials  Y Ravi Shankar, Sibeka Sahoo, M Hari Krishna, P Shameen Kumar, T Satyendra Kumar.  J Dent Implant 2016;6:29-36.
  • 2.  Impression making for the implant is one of the important factor to obtain a good prosthesis. A good implant impression records three dimensional position of implant in oral cavity. An accurate impression is mandatory for the success of implant supported dental prosthesis as an accurate recording of spatial implant position is required to obtain a proper support to definitive restoration with passive fit.
  • 3.  Fixture level or implant level impression-  In this technique position, angulation , orientation to the soft tissue margin of the implant is recorded and abutment is selected accordingly.  Impression copings are used in this technique which are positioned sub gingivally. Prasad DK, Prasad DA, Colaco C. Beyond osseointegration: Clearing the prosthetic dilemma. Indian Journal of Oral Sciences.2016 Jan 1;7(1):11.
  • 4.  Open tray impression technique-  Custom/ stock tray with hole in the implant coping areas is used.  Multiple implant cases.  Implant with severe angulation.  Implants with different angulation.  Reduces the effect of implant angulation, deforming the impression material upon recovery from mouth.  Splinting of the transfer copings prevents rotational movement of impression copings in the impression material during analog fastening.
  • 5.  Transfer Type / Close Tray Technique  the impression copings remain in the mouth on the removal of the set impressions. After the removal of the impression, the impression copings are transferred to the impressions and then the cast is poured.  Limited inter arch space  Tendency to gag  Difficult access in the posterior region of the mouth  Easier  Suitable for short inter arch distance.  Visual fastening of the analog to the coping is more accurate  Inaccuracies with recovery and subsequent deformation of impression material may be encountered with nonparallel implants.  Not Suitable for deeply placed implants Chee W, Jivraj S. Impression techniques for implant dentistry. British dental journal. 2006 Oct;201(7):429.
  • 6.  Abutment level impression  In this technique the position, orientation of the abutment is recorded.  Indirect Impression Technique  The indirect impression technique is a method of making an impression by first connecting the abutments to the implant fixture and subsequently connecting the impression copings to them.  In this technique plastic or snap fit impression technique is used.
  • 7.  Direct Impression Technique-  The direct impression technique involves screwing of the final abutment into the implant in the oral cavity followed by its preparation within the mouth itself using rotary instruments.  Less time consuming  Margins can be prepared according to operators specifications  Single appointment procedure.
  • 8. IMPRESSION MATERIALS 1. Polyvinylsiloxane. 2. Polyether. 3. Vinyl Polyether Siloxane compound developed by combining polyether polymer and vinyl groups of VPS . • Total setting time 2-3 min , Working time 2 min. • Better wettability. The lowest achievable contact angle ,less than 10° after 1 second. • The vinyl siloxane ethers have a dimensional change of ≈ –0.2% . • Hardness (Shore) ≈ A45- 60 . Shetty RM, Bhandari GR, Mehta D. Vinyl Polysiloxane Ether: A Breakthrough in Elastomeric Impression Material. World. 2014 Apr;5(2):134-7.
  • 9. Splinting material for implant impression • Pattern resin. • Flowable composite. • Bite registration paste. • Less polymerization shrinkage. (3%-5%). • Less heat generation. • Less setting time (3-5 min). • More polymerization shrinkage. (7-12%). • More permanent deformation. • No heat generation. • More permanent deformation. Joseph TM, Ravichandran R, Lylajam S, Viswabharan P, Janardhanan K, Rajeev S. Evaluation of positional accuracy in multiple implants using four different splinting materials: An in vitro study. The Journal of Indian Prosthodontic Society. 2018 Jul 1;18(3):239.
  • 10. Aim- to investigate the accuracy of master cast using two impression techniques, i.e. open and closed tray techniques .  To evaluate the accuracy of impression materials including PVS(polyvinylsiloxane), PE(polyether ), and VSE(Vinylsiloxanether) .  To evaluate the effect of splinting and nonsplinting methods and angulations of implants in them.  A U-shaped stainless steel die framework (12 mm × 10 mm × 50 mm) simulating the edentulous mandible fabricated.  Six holes were drilled to a depth of 10 mm and diameter of 4.3 mm with the help of 3D computerized numerical control universal vertical milling machine.  The lab analogs (4.2 mm diameter) were positioned in different angulations and assigned as A, B, R, C, D, and E, the center analogs R . Article Proper
  • 11.  The analogs B and D were placed at an angle of 10° and the analogs A and E were positioned at 20° to the center axis with respect to center analogs.  Six orientation marks were drilled, i.e. three labially and three lingually which were 2 mm wide and 1 mm deep.  Sixty custom impression trays were made with autopolymerizing methacrylate resin with spacer thickness of 3 wax sheet.  The impression trays for open tray technique had six windows to allow access for the copings screws  The impressions for open tray technique were divided primarily into splinted group and the nonsplinted group.  The splinted group was subdivided into two groups; (1) splinting with dental floss and pattern resin and (2) splinting with plastic rod.
  • 12. • subgroup 1, putty index was fabricated at a level just below the grooves of the rectangular part of the impression coping to act as a Scaffold. • Pattern resin (GC ASIA Dental PTE. Ltd.,) was mixed and adapted to surround the copings and dental floss with paintbrush. • The pattern resin was sectioned in the center to create a gap of 0.2 mm between the sectioned parts Impressions were made using three elastomeric impression materials. 1. PVS (Dentsply, medium-bodied) which was mixed in a base and catalyst ratio of 1:1 2. PE (3M ESPE, medium-bodied) in the ratio of 7:1 3. Vinylpolysiloxanether (Identium, medium-bodied) in the ratio of 5:1. subgroup 2, the stirrer was sectioned to fit into the space and was secured to copings with the help of pattern resin .
  • 13.  Impressions were made, and following the setting of the material, analogs were fixed to the copings and casts were poured with Type IV die stone.  The experimental casts were measured in three axes with coordinate measuring machine  The reference point taken for all the measurements was analog R which was perpendicular to the surface of the cast.  The distances in X axis were termed as XA, XB, XC, XD, and XE. The distances in Y axis were designated as YA, YB, YC, YD, and YE. Similarly, for Z axis, it was ZA, ZB, ZC, ZD, and ZE.  The mean and standard deviation of the differences in inter implant distances (IIDs).
  • 14. Parameter PVS PE VSE Dev X 29.40 27.80 24.20 Dev Y 64.40 55.40 48.60 Dev Z 22.60 26.40 16.60 Dev 3D 42,255.80 42,246.80 42,239.80 Dev angle 0.40 0.40 0.20 Dev IID 143.60 127.40 122.80 Parameter PVS PE VSE Dev X 28.40 26.20 24.60 Dev Y 61.60 52.60 43.60 Dev Z 18.80 23.20 16.80 Dev 3D 42,252.80 42,244.20 42,234.60 Dev angle 0.00 0.20 0.40 Dev IID 136.40 122.60 120.60 Results-
  • 15. Parameter PVS PE VSE Dev X 59.40 54.60 44.60 Dev Y 99.40 85.40 71.80 Dev Z 50.40 44.40 36.40 Dev 3D 42,291.80 42,277.60 42,263.80 Dev angle 0.60 0.80 0.60 Dev IID 208.40 148.20 139.60
  • 16.  It is reported that angular positional transfer deformation increases with an increase in an implant’s buccal/ lingual inclination with respect to horizontal crestal plane.  An angulation of 20° and rotational freedom of 1.5° can result in a horizontal misfit up to 127 microns.  In clinical situation, the submandibular fossa mandates implant placement with increasing angulation as it progresses distally. Therefore, in the second premolar region, angulation may be 10° to horizontal plane; in the first molar area, 10–15°; and in the second molar region, 20–25°.  In this study, monophase technique was used as it is accomplished in a single-step procedure using materials with a medium viscosity to allow the material itself to record finer details while avoiding the slumping of the material in the tray, less time-consuming, and simple to perform.  the impression coping remains in the impression, the open tray technique reduces the effect of implant angulation, deforming the impression material upon recovery from mouth, and removes the concern of replacing the copings into the impression. Discussion-
  • 17.  The underlying principle of splinting the impression copings is to connect them together using a rigid material to prevent individual coping movement during the impression making procedure.  The greater deviation with stirrer and resin splint could be attributed to the relative flexibility of the plastic rod compared to the floss and pattern resin.  Hydrophilicity, greater followability, better surface wettability of VSE may lead to accurate impression.  Better tear strength and rigidity of PE leads to more accurate impression than PVS.
  • 18. 1.The open tray technique was more accurate than the closed tray technique when multiple implants are considered 2. The VSE material showed lesser deviation from the reference die compared to PE and PVS. 3. Splinting of the impression copings had a significant effect on the accuracy of the casts. 4. Among the splinting methods used in the present study, splinting with dental floss and acrylic was more reliable than splinting with plastic rod and acrylic. 5. The relation between the angulation and impression material can be established that as with increase in angulation, the amount of forces of deformation increases which require an impression material which can withstand these forces that affect the accuracy of master cast. Conclusions
  • 19.  Critical Evaluation-  Seating load of the impression trays.  Measurement of angular deviation and three dimensional deviation not mentioned.
  • 20.  Comparative analysis of the accuracy of different direct impression techniques for multiple implants.  D Öngűl, B Gökçen-Röhlig, H Keskin.  Australian dental journal. 2012 Jun;57(2):184-9. Aim- evaluate the effect of splinting on implant impression accuracy when making impressions of edentulous arches containing multiple implants.  A reference model of an edentulous maxilla was produced with six Straumann Tissue Level implants.  Experimental Group 1 (EG1): Screw-on synOcta impression copings.  Experimental Group 2 (EG2): Screw-on synOcta impression copings splinted with acrylic resin bar (non-sectioned acrylic bar).  Experimental Group 3 (EG3): Screw-on synOcta impression copings splinted with two separate acrylic resin bars (sectioned acrylic bars). RELEVANT ARTICLES
  • 21.  Experimental Group 4 (EG4): Screw-on synOcta impression copings splinted with light-curing composite resin bar (non- sectioned composite bar).  Experimental Group 5 (EG5): Screw-on synOcta impression copings splinted with two light-curing composite bars (sectioned composite bars).  Polyether impression material (Impregum Penta Soft, 3M ESPE Dental, Medizin, Germany) was used for all impressions.  Dimensional deviations were measured at predetermined points mesial, distal, vestibular and palatal to each implant, for a total of 24 points in each cast.
  • 22. Group Mean Deviation EG1 24.10 EG2 12.70 EG3 22.71 EG4 23.70 EG5 41.09  The sectioned bars (EG3 and EG5) demonstrated more deviation from the master model than the non-sectioned bars.  Splinting of the impression copings should be the ideal method to increase the impression accuracy.  Acrylic resin is the ideal material for splinting.
  • 23.  COMPARATIVE EVALUATION OF THE DIMENSIONAL ACCURACY OF CLOSED TRAY AND OPEN TRAY IMPRESSION TECHNIQUE.  Tandon A, Bulbule NS, Jagtap AK, Kakade DM.  Journal of Clinical & Diagnostic Research. 2017 Nov 1;12(11).. Aim-Evaluating and comparing the accuracy of closed tray to that open tray impression technique and also to compare two different elastomeric impression materials  Four internal connection implants (alfa dent), were placed in the acrylic resin model.  Closed tray : dentulous stock tray  30 : closed tray impression; 15+15 polyether & polyvinyl siloxane  The direct impression transfer copings were screwed into position over the implant fixtures and impressions were made.  Open tray  30 : open tray impression; 15+15 polyether & polyvinyl siloxane
  • 24.  Impression copings were screwed and splinted using cold cure acrylic resin.
  • 25.  The open-tray impression technique exhibited higher accuracy in comparison to closed-tray technique.  The difference in the accuracy of the impressions obtained using polyether and polyvinyl siloxane were not statistically significant.
  • 26.  A comparative analysis of the accuracy of implant master casts fabricated from two different transfer impression techniques.  Rupali Patil, Pankaj Kadam, Seema Patil, Shweta Jajoo.  J Int Prevent Communit Dent 2016;6:142-8. Aim – to find the most accurate impression technique(open/close), along with understanding the influence of tray type (custom/stock) for transfer of intraoral position of implant fixtures on cast.  Edentulous maxillary resin model was made with four implants of Ø 4x 10 mm placed.  The distances between four implants of master models were measured using an optical microscope.  Four impression groups were formed as follows;  Group 1: Stock open tray (SOT) technique  Group 2: Stock closed tray (SCT) technique  Group 3: Custom open tray (COT) technique  Group 4: Custom closed tray (CCT) technique.
  • 27.  All the impressions were stored for 24 h before pouring. Later, Type IV gypsum.  A calibrated optical microscope was used to record the positional accuracy of the implants. Groups A-B distanc e A-b B-C distanc e B-C C-D distanc e C-D A-D distanc e A-D SOT 7.36 mm 7.35 13.95 mm 13.85 8.15 mm 8.08 30.65 mm 30.72 SCT 7.26 13.82 8.16 30.79 COT 7.34 13.91 8.16 30.70 CCT 7.55 14.10 8.22 30.80
  • 28.  The open tray impression technique is more accurate as compared to the closed tray technique.  COT shows the most accurate impression technique among all.
  • 29.  Accuracy of various impression materials and methods for two implant systems: An effect size study.  Alexander Schmidt,Teresa Häusslinga, Peter Rehmanna, Heidrun Schaaf.  Journal of prosthodontic research. 2018;62(2):245-51 Aim-To determine the effect of the impression material/method (open or close tray), and implant angulation ( 0°, 15°,20°)on impression transfer precision.  An upper jaw model with three BEGO and three Straumann implants (angulations 0°, 15°, 20°) in the left and right maxilla was used as a reference model.  One polyether (Impregum Penta IP) and two polyvinylsiloxane (Flexitime Monophase FM/Aquasil Ultra Monophase AU) based materials were used as impression materials.  For the open tray technique impression copings were splinted and for closed tray impression plastic transfer caps were used.  For open tray technique custom impression tray was fabricated with holes in implant areas.
  • 30.  For the measuring procedure, angled abutments with different angulations (0°, 15°, 20°) were placed on the respective angled implants.  A Rapid coordinate measurement machine was used to measure the target variables with respect to accuracy for the 3D shift.  IP1-Polyether Open tray.  IP2-Polyether Closed tray.  FM1-Polyvinyl siloxane Open tray.  FM2- Polyvinyl siloxane Closed tray.  AU1- Polyvinyl siloxane Open tray .  AU2-Polyvinyl siloxane Closed tray
  • 31.  The impression method (open/closed tray) generated differences in the impression accuracy, with no significant difference.  Compared to polyether, polyvinyl siloxane materials showed the highest transfer accuracy, with significant difference in the 3D shift.  Implant system did not affect the accuracy of impression.
  • 32.  A Comparison of implant impression precision: Different materials and techniques.  Mahtab Tabesh, Marzieh Alikhasi, Hakimeh Siadat.  J Clin Exp Dent. 2018;10(2):e151-7 Aim-to compare polyvinyl siloxane, polyether and vinyl siloxanether impressions with two techniques of direct and indirect impression making in terms of precision.  A master model of edentulous maxilla was constructed includingFour implants of Ø 4.3 x 11 mm .  Anterior two implants were parallel to each other and perpendicular to edentulous ridge while posterior ones were tilted 45° distally.  Seventy two 2mmthick custom trays (36 open and 36 closed trays) were fabricated. Impession wee taken using polyether (PE), polyvinyl siloxane (PVS), and vinyl siloxanether (VSE) materials.
  • 33.  For each implant on the casts, the x, y and z coordinates were measured by recording the distances from the reference point on the center of the superior surface of the reference cylinder to center of the implant in each dimension. x (mm) y (mm) z (mm) r (mm) Polyvinyl Siloxane 0.133 .101 .232 .314 0.179 .138 .599 .683 Polyether .089 .069 .148 .206 .143 .120 .180 .306 Vinyl Siloxanether .117 .105 .199 .294 .155 .086 .252 .335
  • 34.  For closed technique is considered polyether is the better choice.  For open technique polyether and vinyl siloxanether are choices. If vinyl siloxanether is the material, then both open and closed techniques are favorable.
  • 35.  Digital vs. conventional full-arch implant impressions: a comparative study  Sarah Amin,Hans Peter Weber,Matthew Finkelman,Khaled El Rafie.  Clinical oral implants research. 2017 Nov;28(11):1360-7. Aim-To test whether or not digital full-arch implant impressions with two different intra-oral scanners (CEREC Omnicam and True Definition) have the same accuracy as conventional ones.  A stone master cast representing an edentulous mandible using five internal connection implant was fabricated.  The three median implants were parallel to each other, the far left implant had 10°, and the far right had 15° distal angulation.  splinted open-tray technique was used for the conventional polyether impressions (n = 10) for Group 1. Digital impressions (n = 10) were taken with two intraoral optical scanners (CEREC Omnicam and 3M True Definition) after connecting polymer scan bodies to the master cast for groups 2 and 3.
  • 36.  Master cast and conventional impression test casts were digitized with a high-resolution reference to obtain digital files. Digital full-arch implant impressions using True Definition scanner and Omnicam were significantly more accurate (trueness) than the conventional impressions
  • 37.  Conclusions-  The impression of implants has several differences compared to the impression of natural teeth and the clinician should take these differences under consideration. Careful selection of the proper impression material and technique according to the needs of each clinical case is of vital importance to achieve the construction of an accurate working cast.
  • 38.  Bibliography • Amin S, Weber HP, Finkelman M, El Rafie K, Kudara Y, Papaspyridakos P. Digital vs. conventional full‐arch implant impressions: a comparative study. Clinical oral implants research. 2017 Nov;28(11):1360-7. • Patil PS. A comparative analysis of the accuracy of implant master casts constructedd from two different transfer impression techniques-an in vitro study. • Tabesh M, Alikhasi M, Siadat H. A comparison of implant impression precision: Different materials and techniques. Journal of clinical and experimental dentistry. 2018 Feb;10(2):e151. • Schmidt A, Häussling T, Rehmann P, Schaaf H, Wöstmann B. Accuracy of various impression materials and methods for two implant systems: An effect size study. Journal of prosthodontic research. 2018;62(2):245-51. • Prasad DK, Prasad DA, Colaco C. Beyond osseointegration: Clearing the prosthetic dilemma. Indian Journal of Oral Sciences. 2016 Jan 1;7(1):11. • Chee W, Jivraj S. Impression techniques for implant dentistry. British dental journal. 2006 Oct;201(7):429. • Shankar YR, Sahoo S, Krishna MH, Kumar PS, Kumar TS, Narula S. Accuracy of implant impressions using various impression techniques and impression materials. Journal of Dental Implants. 2016 Jan 1;6(1):29.