Recording and reproducing cast orientation by using an ... · duced on the adjustable table of a...
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DENTAL TECHNIQUE Recording and reproducing cast orientation by using an implant impression coping and implant analog: A dental technique Jung-Jin Lee, DDS, MSD, PhD, a Won-Suk Oh, DDS, MS, b and Jae-Min Seo, DDS, PhD c The orientation of a definitive cast should be recorded and reproduced to indicate the most appropriate path of placement and undercut areas for the fabrication of a removable partial denture (RPD). One common method of recording the cast orientation is to tripod or score the cast base to indicate the determined path of placement. 1,2 However, an error may occur when the cast orientation needs to be repro- duced on the adjustable table of a surveyor because of the different positions of the analyzing rod and viewing angle. 3 The reproducibility of tripoding or scoring method relies on the relationship of the cast base to the adjustable table of a surveyor. However, the relation- ship of the base to the table may vary with different mechanisms of cast attachment and possible alteration of the base. Several methods 4-8 have been introduced to avoid the problems associated with the inconsistent relationship of the base to the table by orienting the cast as reference to the vertical arm of a surveyor. However, these methods require laboratory procedures to fabricate additional devices with adjustable arms and metal pins and sleeves, inclinometers, and magnetic devices. This article describes a straightforward and accurate method of recording and reproducing the cast orientation by using an implant impression coping and an implant analog. This method allows the cast to be oriented as reference to the vertical arm of a surveyor and eliminates the uncertainty related to tripoding or scoring the base of the cast. In addition, the orientation of the original definitive cast can be transferred to a duplicate cast with the direct impression transfer coping replaced by an in- direct impression transfer coping while making a dupli- cate impression. TECHNIQUE 1. Mount the definitive RPD cast on the adjustable table of a surveyor (Ney surveyor parallometer; Dentsply Sirona) to orient the occlusal plane of the cast parallel to the platform. 2. Secure the adjustable table of a surveyor (Ney Surveyor Parallometer; Dentsply Sirona), after determining the most desirable path of placement by tilting the table in the anterior-posterior or lateral direction and by taking into consideration the guide plane, retention, interference, and esthetics. 3. Use a tungsten carbide bur (Tungsten carbide cutter; NTI-Kahla GmbH) to create a vertical groove a Clinical Professor, Department of Prosthodontics, Institute of Oral Bio-Science, School of Dentistry, Chonbuk National University, and Research Institute of Clinical Medicine of Chonbuk National University-Biomedical Research Institute of Chonbuk National University Hospital, Jeonju, Republic of Korea. b Clinical Professor, Department of Biologic and Materials Sciences, Division of Prosthodontics, University of Michigan School of Dentistry, Ann Arbor, Mich. c Associate Professor, Department of Prosthodontics, Institute of Oral Bio-Science, School of Dentistry, Chonbuk National University, and Research Institute of Clinical Medicine of Chonbuk National University-Biomedical Research Institute of Chonbuk National University Hospital, Jeonju, Republic of Korea. ABSTRACT For the fabrication of a removable partial denture, the orientation of a definitive cast should be recorded and reproduced to indicate the most desirable path of placement and undercut areas. This article describes a straightforward and accurate method of recording and reproducing the cast orientation by using an implant impression coping and an implant analog. (J Prosthet Dent 2018;119:33-35) THE JOURNAL OF PROSTHETIC DENTISTRY 33 Downloaded for scmh lib ([email protected]) at Show Chwan Memorial Hospital JC from ClinicalKey.com by Elsevier on January 09, 2018. For personal use only. No other uses without permission. Copyright ©2018. Elsevier Inc. All rights reserved.
Transcript of Recording and reproducing cast orientation by using an ... · duced on the adjustable table of a...
DENTAL TECHNIQUE
aClinical ProfMedicine of CbClinical ProfcAssociate PrMedicine of C
THE JOURNA
Recording and reproducing cast orientation byusing an implant impression coping and implant analog:
A dental technique
Jung-Jin Lee, DDS, MSD, PhD,a Won-Suk Oh, DDS, MS,b and Jae-Min Seo, DDS, PhDcABSTRACTFor the fabrication of a removable partial denture, the orientation of a definitive cast should berecorded and reproduced to indicate the most desirable path of placement and undercut areas.This article describes a straightforward and accurate method of recording and reproducing thecast orientation by using an implant impression coping and an implant analog. (J Prosthet Dent2018;119:33-35)
The orientation of a definitivecast should be recorded andreproduced to indicate themost appropriate path ofplacement and undercut areasfor the fabrication of aremovable partial denture
(RPD). One common method of recording the castorientation is to tripod or score the cast base to indicatethe determined path of placement.1,2 However, an errormay occur when the cast orientation needs to be repro-duced on the adjustable table of a surveyor because of thedifferent positions of the analyzing rod and viewingangle.3The reproducibility of tripoding or scoring methodrelies on the relationship of the cast base to theadjustable table of a surveyor. However, the relation-ship of the base to the table may vary with differentmechanisms of cast attachment and possible alterationof the base. Several methods4-8 have been introduced toavoid the problems associated with the inconsistentrelationship of the base to the table by orienting thecast as reference to the vertical arm of a surveyor.However, these methods require laboratory proceduresto fabricate additional devices with adjustable arms andmetal pins and sleeves, inclinometers, and magneticdevices.
This article describes a straightforward and accuratemethod of recording and reproducing the cast orientationby using an implant impression coping and an implant
essor, Department of Prosthodontics, Institute of Oral Bio-Science, Schoolhonbuk National University-Biomedical Research Institute of Chonbuk Naessor, Department of Biologic and Materials Sciences, Division of Prosthodofessor, Department of Prosthodontics, Institute of Oral Bio-Science, Schohonbuk National University-Biomedical Research Institute of Chonbuk Na
L OF PROSTHETIC DENTISTRY
Downloaded for scmh lib ([email protected]) at Show Chwan MemoriaFor personal use only. No other uses without permission.
analog. This method allows the cast to be oriented asreference to the vertical arm of a surveyor and eliminatesthe uncertainty related to tripoding or scoring the base ofthe cast. In addition, the orientation of the originaldefinitive cast can be transferred to a duplicate cast withthe direct impression transfer coping replaced by an in-direct impression transfer coping while making a dupli-cate impression.
TECHNIQUE
1. Mount the definitive RPD cast on the adjustabletable of a surveyor (Ney surveyor parallometer;Dentsply Sirona) to orient the occlusal plane of thecast parallel to the platform.
2. Secure the adjustable table of a surveyor (NeySurveyor Parallometer; Dentsply Sirona), afterdetermining the most desirable path of placementby tilting the table in the anterior-posterior or lateraldirection and by taking into consideration the guideplane, retention, interference, and esthetics.
3. Use a tungsten carbide bur (Tungsten carbide cutter;NTI-Kahla GmbH) to create a vertical groove
of Dentistry, Chonbuk National University, and Research Institute of Clinicaltional University Hospital, Jeonju, Republic of Korea.ontics, University of Michigan School of Dentistry, Ann Arbor, Mich.ol of Dentistry, Chonbuk National University, and Research Institute of Clinicaltional University Hospital, Jeonju, Republic of Korea.
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Figure 1. Placement of vertical groove for implant analog in posterioraspect of definitive cast for fabrication of removable partial denture.
Figure 2. Impression coping-analog assembly: 1) implant analog, 2)short, direct impression coping; 3) long retaining screw.
Figure 3. Definitive cast demonstrating long retaining screw extendedabove short direct impression coping to indicate orientation of cast.
Figure 4. Definitive cast oriented by means of long retaining screwsecured to vertical arm of surveyor.
34 Volume 119 Issue 1
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(approximately 10 mm in depth and 20 mm inlength) in the posterior aspect of the base (Fig. 1).
4. Connect a short, direct impression coping (DentiumCorp) to an implant analog (Dentium Corp) bymeans of a long retaining screw (Dentium Corp)(Fig. 2) and secure the coping-analog assembly tothe vertical arm of a surveyor (Ney SurveyorParallometer; Dentsply Sirona).
5. Position the coping-analog assembly in the verticalgroove of the cast and attach it to the cast with athermoplastic adhesive material (Hot melt stick;Okong Corp) (Figs. 3, 4) in an electric heat gun(Gluegun G-250; Okong Corp).
6. Replace the direct transfer impression coping withan indirect transfer impression coping (DentiumCorp) to transfer the orientation of the originaldefinitive cast to a duplicate cast (Fig. 5).
7. Make an impression of the definitive cast with apolyvinyl siloxane duplicating material (PolyPour;GC Corp) to duplicate the cast and separate theimpression from the cast. Unscrew the indirect
E JOURNAL OF PROSTHETIC DENTISTRY
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transfer coping from the implant analog attached tothe original definitive cast and connect it to anotherimplant analog (Dentium Corp) and reseat thecoping-analog assembly in the duplicate impression(Fig. 6).
8. Pour the duplicate impression in Type IV dentalstone (Fujirock EP; GC Corp) to fabricate a duplicatecast and transfer the orientation of the originalmaster cast to the duplicate cast by means of thecoping-analog assembly reseated in the impression.Replace the indirect transfer coping with a directtransfer coping to indicate the orientation of theoriginal definitive cast by means of an extension ofthe retaining screw.
DISCUSSION
This method of recording the cast orientation for thefabrication of an RPD requires a laboratory procedure toattach an implant analog to the cast. The implant analogis located in the posterior aspect of the cast base to avoid
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Figure 5. Definitive cast demonstrating indirect impression copingconnected to implant analog to transfer cast orientation to duplicatecast.
Figure 6. Duplicate impression demonstrating reseated implant analogand indirect impression transfer coping assembly.
January 2018 35
interference with the design of a maxillary majorconnector. In particular, for a palatal plate, majorconnector extended to the junction of hard and softpalates.9 The analog is secured to the stone cast with athermoplastic adhesive material to expedite the attach-ment and separation procedures for reusing the analog.
The impression coping should be short enough toallow the retaining screw to extend above the coping.The retaining screw should also be sufficient in diameterto be inserted into and engaged by the vertical arm of asurveyor. The retaining screw can be directly connectedto the implant analog without using the impressioncoping to indicate the cast orientation when adequatesizes of the impression coping and retaining screw areunavailable.
The impression transfer coping is unscrewed fromthe implant analog when the cast is articulated againstthe opposing cast and is reconnected to the analog in thelaboratory to indicate the cast orientation determined bythe dentist. The direct impression transfer coping is
Lee et al
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replaced with an indirect transfer coping to transfer theorientation of the original definitive cast while making animpression to duplicate the cast. This procedure keepsthe original definitive cast unaltered for future use, andthe duplicate cast used for waxing of the RPD metalframework.
This procedure is straightforward and ensures an ac-curate orientation of the cast with the elimination of er-rors resulting from a positional relation of the cast to theadjustable table of a surveyor. In addition, the implantimpression transfer copings and analogs are commonlyavailable and can be used repeatedly. However, careshould be taken to avoid a dislodgement of the implantanalog from the cast and to have a sufficient extension ofthe retaining screw above the impression coping forsecure connection to the vertical arm of a surveyor.
SUMMARY
This method of recording and reproducing the castorientation by using an implant impression coping andan implant analog eliminates the uncertainty related totripoding or scoring the cast base and allows the orien-tation of the original definitive cast to be transferred to aduplicate cast while keeping the original definitive castunaltered for future use. However, care needs be taken toavoid dislodgement of the implant analog from the castand to present a sufficient extension of the retainingscrew above the impression transfer coping for secureconnection to the vertical arm of a surveyor.
REFERENCES
1. Wagner AG, Forgue EG. A study of four methods of recording the path ofinsertion of removable partial dentures. J Prosthet Dent 1976;35:267-72.
2. Carr AB, Brown DT. McCracken’s removable partial prosthodontics. 13th ed.St. Louis: Mosby; 2015:135-40.
3. Sayed ME, Busaily IA, Nahari RJ, Hakami RO, Maashi SM, Ramireddy NR.Evaluation of cast re-orientation on a dental surveyor using three tripodtechniques: a survey and in vitro study. J Prosthodont 18 Jan 2017. doi: 10.1111/jopr.12581. [Epub ahead of print].
4. Steas AD. Recording and reproducing the tilt of a cast on a surveyor. J ProsthetDent 1987;57:121-5.
5. Bezzon OL, Bezzon OL, Ribeiro RF, Ribeiro RF, Pagnano VO, Pagnano VO.Device for recording the path of insertion for removable partial dentures.J Prosthet Dent 2000;84:136-8.
6. Dumbrigue HB, Chingbingyong MI. A new method for recording and repro-ducing cast orientation on a survey table. J Prosthet Dent 2003;89:76-8.
7. Kamble VD, Parkhedkar RD, Bhowmik H. A magnetic device for recording andreproducing the path of placement for partial removable dental prostheses.J Prosthet Dent 2013;110:333-4.
8. Patil PG, Nimbalkar-Patil SP. Simple technique to reorient different casts ofsame patient on a dental surveyor. J Prosthodont 22 Jun 2016. doi: 10.1111/jopr.12491. [Epub ahead of print].
9. Henderson D. Major connectorsdunited it stands. Dent Clin North Am1973;17:661-78.
Corresponding author:Dr Jae-Min SeoDepartment of Prosthodontics and Institute of Oral BioscienceChonbuk National University School of Dentistry20, Geonjiro Deokjin-gu, Jeonju-si, Jeollabuk-do, 54907Republic of KoreaEmail: [email protected]
Copyright © 2017 by the Editorial Council for The Journal of Prosthetic Dentistry.
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