A sc

tray

Gregory J. Papro

aAssistant Professor and Director, MHead and Neck Cancer Clinic.bAssistant Professor, Department ofcAssistant Professor, Department of

Paprocki et al

rew-connected sectional impression

for patient with limited opening

cki, DDS,a Sanjay Karunagaran, BDS, DDS, MSD,b

and Vinay Jain, BDS, MS, MDSc

University of Tennessee, Health Science Center College of Dentistry,Memphis, Tenn

A procedure for fabricating a 2-piece custom tray is described. Implant analogs and gold cylinders are used to maximize theprecision of the fit and the stability of the tray. (J Prosthet Dent 2013;-:---)

1 Shortened external hexagon laboratory analog.

Microstomia can be the resultof disease, surgery, or accidents.1-6

Regardless of the cause, a limited oralopening greatly complicates impressionmaking. A number of creative ap-proaches to designing and fabricatingsectional trays have been described.Most of these approaches use sometype of mechanical interlock to join thesegments of the tray.7-12 Mirfazaelian13

described the use of an orthodonticexpansion screw for joining the parts ofa sectional impression tray. Whereasthe jack screw retained the 2 parts, theinterlock was dependent on pins fittingmechanically into the acrylic resin tray.Ohkubo et al14 described the modifi-cation of stock metal trays, whichconsisted of a disk with pins thatindexed into holes in the metal trayhandle and was fastened to the seg-ments with a screw, thereby fixing thesegments in position. This article de-scribes a technique that uses modifiedexternal hexagonal analogs, gold cylin-ders, and long impression pins toensure accurate repositioning of thetray segments after removal of theimpression.

TECHNIQUE

1. Modify a stock impression trayto the extent necessary to obtain an

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ProsthodoProsthodo

impression with an approximate archform and tooth position.

2. Pour the impression in Type IIIstone (Microstone; Whip Mix Corp).

3. Place wax (Shur Wax; HeraeusKulzer LLC) over the cast to providespace in the custom impression tray forthe impression material.

4. Fabricate the first section ofthe sectional tray from visible light-polymerized composite resin tray ma-terial (Triad TranSheet; Dentsply Int).

5. With a cast trimmer, create a per-fectlyflat surfaceon theportionof the traythat will dock with the second segment.

6. Apply a thin coat of separator(Swan Petroleum Jelly; Vi-Jon) to theflat surface of the first segment.

l Prosthodontics; Assistant Director, Advanced

ntics.ntics.

7. Replace the first segment on thepreliminary cast.

8. Fabricate the second segmentof the sectional tray, taking careto achieve intimate contact withthe flat surface of the first traysegment.

9. Remove the second tray segmentand inspect the surface that will dockwith the flat surface of the first segmentto obtain an intimate fit.

10. Reposition both the segmentsand secure with sticky wax (Sticky Wax;Spofa Dent a Kerr Company).

11. Shorten an external hexagonalanalog (Nobel Biocare AB) to approxi-mately 3 to 4 mm (hexed, threadedend) (Fig. 1).

Prosthodontic Program, Co-Director,

2 Obsolete gold cylinder could substi-tute for multiunit abutment or impres-sion coping.

3 Modified analog, gold cylinder, and tray assembly fixed byguide pins.

4 Impression of first segment, note excess material.

2 Volume - Issue -

The Journal of Prosthetic Dentistry

12. Fasten gold cylinders (NobelBiocare AB) to the external hexagonalanalogs with a guide pin (Nobel Bio-care AB) (Fig. 2).

13. Fasten the analog to the firsttray segment and the gold cylinder tothe second tray segment with clearvisible light-polymerized resin compos-ite (Triad Gel; Dentsply Intl) by takingcare to position the interface of thecylinder and the analog at the junctionof the first and second tray segments(Fig. 3).

14. Make the impression of the firstsegment with an elastomeric impres-sion material (Aquasil Ultra XLV Re-gular set, Aquasil Ultra MonophaseRegular; Dentsply Intl) (Fig. 4).

15. Remove the impression todetermine the path of removal andallow the trimming of excess materialflush with the flat surface of the tray.

16. Reposition the first segment inthe mouth (Fig. 5).

17. Load the second segment withimpression material, insert the tray, andsecure to the first segment with theguide pins.

18. After the material has polymer-ized, unscrew the guide pins andremove the segments separately.

19. Reassemble the segments withthe guide pins (Fig. 6).

DISCUSSION

A sectional tray fabricated with thetechnique described in this article canbe configured in multiple ways inde-pendent of the position of the handle.The technique can be altered to have asmany segments as needed. The accu-racy of the fit of the segments of thetray can be judged clinically at the timeof the impression by observing the fit ofthe machined implant components.Likewise, the segments can be reas-sembled with a high degree of accuracyas evidenced by the slight seamobserved on the resultant cast wherethe segments were joined (Fig. 7).

Care must be taken during theimpression to orient the first traysegment as it was fabricated on the cast.If it is rolled to the lingual, then

Paprocki et al

5 Repositioned tray, note excess material removed flushwith flat surface.

6 Impression reassembled after removal.

7 Note fit of lingual surface and minimal seam wheresegments were rejoined (arrow).

- 2013 3

positioning the second tray segmentmaybe impossible because of occlusal inter-ference. If the first tray segment is rolledto the buccal, then the second segmentmay be suspended over the remainingarch and the impression material maynot be adequately supported. In either

Paprocki et al

event, the impression of the first segmentwill need to be remade. Although aspecific type of implant system was usedfor this technique, any implant systemwith a precision fitting analog andcomponents joined with a screw couldbe used.

SUMMARY

This article describes a techniquefor fabricating a custom segmentalimpression tray with readily availableimplant components. The tray can befabricated with as many segments asnecessary and can be reassembled witha high degree of accuracy.

REFERENCES

1. Winkler S, Wongthai P, Wazney JT. Animproved split-denture technique. J ProsthetDent 1984;51:276-9.

2. McCord JF, Tyson KW, Blair IS. A sectionalcomplete denture for a patient with micro-stomia. J Prosthet Dent 1989;61:645-7.

3. Nayloor WP, Manor RC. Fabrication of a flexibleprosthesis for the edentulous scleroderma patientwithmicrostomia. JProsthetDent1983;50:536-8.

4. Dhanasomboon S, Kiatsiriroj K. Impressionprocedure for a progressive sclerosis patient: aclinical report. J Prosthet Dent 2000;83:279-82.

5. Baker P, Brandt RL, Boyajian G. Impressionprocedure for patients with severely limitedmouth opening. J ProsthetDent 2000;84:241-4.

6. Cheng AC, Wee AG, Tat-Keung L. Maxillo-facial prosthetic rehabilitation of a midfacialdefect complicated by microstomia: a clinicalreport. J Prosthet Dent 2001;85:432-7.

7. Cheng AC, Wee AG, Morrison D,Maxymiw WG. Hinged mandibular removablecomplete denture for post-mandibulectomypatients. J Prosthet Dent 1999;82:103-6.

8. Geckili O, Cilngir A, Bilgin T. Impression pro-cedures and constructionof a sectional dentureforapatientwithmicrostomia: a clinical report.J Prosthet Dent 2006;96:387-90.

9. Hegde C, Prasad K, Prasad A, Hegde R.Impression tray designs and techniques forcomplete dentures in cases of microstomia: areview. J Prosthodont Res 2012;56:142-6.

10. Benetti R, Zupi A, Toffanin A. Prosthetic reha-bilitation for a patient with microstomia: aclinical report. J Prosthet Dent 2004;92:322-7.

11. Suzuki Y, Abe M, Hosoi T, Kurtz KS. Sectionalcollapsed denture for a partially edentulouspatient with microstomia: a clinical report.J Prosthet Dent 2000;84:256-9.

12. Colvenkar SS. Sectional impression tray andsectional denture for a microstomic patient.J Prosthodont 2010;19:161-5.

13. Mirfazaelian A. Use of orthodontic expansionscrew in fabricating section custom trays.J Prosthet Dent 2000;83:474-5.

14. Ohkubo C, Ohkubo C, Hosoi T, Kurtz KS.A sectional stock tray system for makingimpressions. J Prosthet Dent 2003;90:201-4.

Corresponding author:Dr Gregory J. PaprockiUniversity of Tennessee Health Science CenterCollege of Dentistry875 Union AvenueMemphis, TN 38163

Copyright ª 2013 by the Editorial Council forThe Journal of Prosthetic Dentistry.