Use of Pindex System in Fabrication of the Sectional CustomTrayEhsan Jabbari, DDS, MS,1 Omid Savabi , DDS, MS,2 & Farahnaz Nejatidanesh, DDS, MS3

1Postgraduate Student, Department of Prosthodontics, School of Dentistry, Isfahan University of Medical Sciences, Isfahan, Iran2Professor, Torabinejad Dental Research Center, Department of Prosthodontics, School of Dentistry, Isfahan University of Medical Sciences,Isfahan, Iran3Professor, Dental Materials Research Center, Department of Prosthodontics, School of Dentistry, Isfahan University of Medical Sciences, Isfahan,Iran

Keywords

Dental impression technique; denture design;microstomia.

Correspondence

Dr. Farahnaz Nejatidanesh,#400-Sheikhsadoogh Shomali St.,Sheikhsadoogh Cross Road, Isfahan, Iran81648-13315. E-mail: nejati@dnt.mui.ac.ir

The authors deny any conflicts of interest.

Accepted September 3, 2013

doi: 10.1111/jopr.12134

AbstractThis article describes a new, precise, and simple method for making an impressionwith an individual tray for a patient with microstomia. In this method, a Pindex systemon the handle of the tray was used for attaching two parts of the sectional tray.

A fundamental step for a successful prosthesis is making aprecise impression. One problem in making the impressionis that a limited oral opening leads to a compromised impres-sion and, subsequently, a compromised prosthesis.1,2 Microsto-mia may result from surgical treatment of orofacial neoplasms,cleft lips, maxillofacial trauma, burns, radiotherapy, Plummer-Vinson Syndrome, temporomandibular joint dysfunction, orscleroderma.3

Modeling plastic impression compound,4 sectioned stocktrays,1,5 and flexible silicone putty6 have been recommendedfor preliminary impressions. Several techniques have been de-scribed for making the impression for patients with limited in-traoral access.1,2,7-13 Benetti et al1 prepared a stepped butt-jointin a sectional tray handle to make the definitive impression.Geckili et al2 fabricated two-piece custom-made tray with an-terior and posterior parts connected by vertical rods. Lockinglever mechanism,8 press button,9 and orthodontic expansionscrews13 have also been used for joining the tray sections. Curaet al10 used a foldable tray with metal pins and an acrylic resinblock to attach the sections of the impression tray.

The connection of sectional trays for making the final im-pression is critical for fabricating a precise prosthesis. Lack ofadequate connecting strength of the joint may cause impressiondeformation.

This article describes a method for fabricating a customsectional tray for edentulous patients with restricted maximal

opening using the Pindex system and photopolymerizing traymaterials. The Pindex system has been used in preparingworking dies in fixed prosthodontics and has shown reliablestability.14

Technique

1. Make a preliminary impression with irreversiblehydrocolloid material (Alginoplast; Heraeus Kulzer,Hanau, Germany) with the method described byMoghadam5 and provide a study cast (Moldano;Heraeus Kulzer).

2. Attach two pins (Pindex; Coltene/Whaledent, Altstatten,Switzerland) with their sleeves by sticky wax (ModelCement; Kemdent, Swindon, UK) so the pins’ removalpath is parallel.

3. Make appropriate relief, block out on the maxillary studycast, and cover half the cast with a photo-polymerizedtray material sheet (Megatray; Megadenta, Radeberg,Germany) 2 to 3 mm beyond the midline.

4. Create a step finishing line at the medial edge of the firstsection of the tray.

5. Attach pins and sleeves to the handle region of the trayperpendicular to the midline by tray material (Megatray)and cure it (Fig 1A).

417Journal of Prosthodontics 23 (2014) 417–419 C© 2014 by the American College of Prosthodontists

Pindex System for Custom Tray Jabbari et al

Figure 1 A: Pins and sleeves attached to the handle region of the tray.B and C: Two parts of the tray can be assembled by the Pindex system.

6. Lubricate the first half of the tray with petroleum jelly(Vaseline; Tyco Health Care, Montreal, Canada) and fab-ricate the second half. Ensure this part of the tray encom-passes the pin sleeves and adapts to the step finishing line.Then cure the tray material (Megatray) (Figs 1B, 1C).

7. Evaluate extensions and fit of each part of the sectionaltray in the patient’s mouth (Figs 2A, 2B).

8. Make final impression (Impregum F; 3M ESPE, St. Paul,MN) of the first part. After removing the tray, trim theexcess impression material from the finishing line andlubricate (Vaseline) it to facilitate separation of the twoparts after the final impression of the second part.

9. Insert the first part of the impression and make the finalimpression of the second part (Impregum F).

10. Separate the two parts of the tray and remove the impres-sions from the patient’s mouth one at a time.

Figure 2 A and B: Try-in two sections of the tray in the patient’s mouth.C and D: Final impression.

11. Attach the two parts of the impression and ensure theircorrect positioning (Figs 2C, 2D).

Discussion

Prosthodontic management of patients with microstomiapresents a challenge for the clinician. A restricted maximalopening sometimes results in compromised impressions. A sec-tional tray that provides ease in placement and removal can beeffective in treatment of these patients.

418 Journal of Prosthodontics 23 (2014) 417–419 C© 2014 by the American College of Prosthodontists

Jabbari et al Pindex System for Custom Tray

In the described technique, the two-part custom impressiontray allows for a functional impression despite the difficultiesassociated with microstomia. The advantages of such a customtray include patient convenience, simplified insertion and re-moval of the two separate segments, decreased patient trauma,and precise intra- and extraoral assembling of the tray sections.The location of the pins in the most available space (tray han-dles) provides patient comfort and simplifies the handling ofthe two segments. The fabrication of sectional trays with thedescribed method is easy and more precise than with othertechniques.2,8,10,13 In addition, these laboratory pins limit hori-zontal and vertical movement of the two parts, eliminating theneed for posterior elements for joining two segments. The Pin-dex system is easily available and has been successfully usedas a removable die approach in fixed prosthodontics with theleast horizontal movement.14

Stepped butt-joints1 and press buttons9 have been describedfor assembling segments of sectional trays; however, thesemechanisms cannot maintain a stable and durable connection.Locking lever mechanisms do not have enough durability andcannot maintain the position of the sectional tray parts. Bakeret al.8 recommend the use of sticky wax to stabilize the lockingcomponents. The use of a foldable tray with metal pins andacrylic resin block for attaching the sections has also been re-ported for sectional trays in patients with microstomia, but theposition of these components in the posterior area could com-plicate the procedure.10 Geckili et al2 described a techniquefor making the sectional tray, but in their technique, the finalimpresion should be removed in a single piece from the pa-tient’s mouth, which cannot be possible in all cases. Similar toother methods, the disadvantage of the present technique maybe additional time, cost, and effort for making a sectional tray.

Summary

In this report a simple, accurate method for fabrication of thesectional individual tray for patients with a constricted oralopening was described. This method provides a precise con-nection of the two halves of the tray.

References

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