|Year : 2014 | Volume
| Issue : 2 | Page : 65-67
A sectional impression tray technique for an oral submucous fibrosis patient with limited mouth opening
Sowmya Mangalore Kumar, Prasad D Krishna, Rushad Hosi Nariman
Department of Prosthodontics and Crown and Bridge, A B Shetty Memorial Institute of Dental Sciences, Mangalore, Karnataka, India
|Date of Web Publication||10-Mar-2015|
Rushad Hosi Nariman
Department of Prosthodontics, A B Shetty Memorial Institute of Dental Sciences, 2nd Floor, Derlakatte, Mangalore - 575 018, Karnataka
Source of Support: None, Conflict of Interest: None
Oral submucous fibrosis (OSMF) is a precancerous condition. It causes difficulty in swallowing, chewing and speaking due to the presence of microstomia. Limited mouth opening is considered as a hindrance in prosthodontic rehabilitation of a patient. Special impression procedures and techniques should be considered for making an impression in such cases. This article describes the fabrication of a split impression tray to make a secondary impression of an edentulous patient having OSMF.
Keywords: Microstomia, sectional tray, submucous fibrosis
|How to cite this article:|
Kumar SM, Krishna PD, Nariman RH. A sectional impression tray technique for an oral submucous fibrosis patient with limited mouth opening. J Oral Res Rev 2014;6:65-7
|How to cite this URL:|
Kumar SM, Krishna PD, Nariman RH. A sectional impression tray technique for an oral submucous fibrosis patient with limited mouth opening. J Oral Res Rev [serial online] 2014 [cited 2019 May 19];6:65-7. Available from: http://www.jorr.org/text.asp?2014/6/2/65/152912
| Introduction|| |
Oral submucous fibrosis (OSMF) is a chronic inflammatory disease that results in progressive juxtaepethelial inflammatory reaction followed by a fibroelastic change of lamina propia with epithelial atrophy leading to stiffness of the oral mucosa, causing trismus. It is most commonly related to the habit of tobacco chewing. Consumption of chilies, deficiency of iron and B - complex, smoking, alcohol and tobacco play a significant role in the initiation of the disease. The most serious consequences of OSMF is malignant transformation or development of squamous cell carcinoma of affected tissues, which occurs in 3-6% of the cases. 
Limited mouth opening in patients is a common occurrence in prosthodontic practice. Microstomia is defined as an abnormally small orifice.  Prosthetic rehabilitation of patients with limited mouth opening presents difficulties at all stages right from the preliminary impressions to insertion of prostheses. Because such patients have small oral opening, it may be extremely difficult to make impressions and fabricate dentures using conventional methods. 
Different management techniques described are surgeries, use of dynamic opening devices and modification of denture design. In prosthetic treatment, the loaded impression tray is the largest item requiring the intra-oral placement. During impression procedures, wide mouth opening is required for proper tray insertion and alignment, which is not possible in patients with restricted mouth opening. 
This article describes a unique way of fabrication of a custom tray and making a secondary impression for an OSMF patient who has limited mouth opening.
| Case Report|| |
A 46-year-old man with limited oral opening caused by OSMF sought treatment at A.B. Shetty Memorial Institute of Dental Sciences, Mangalore for mandibular and maxillary dentures. His chief complaint was burning the sensation of the mouth on eating spicy food and difficulty in mouth opening since 3 years. Patient had a habit of chewing areca nuts with paan 4-5 times/day since 7 years. His oral opening vertically was measured and found to be 31 mm [Figure 1]a] and intercommissural length was 40 mm [Figure 1]b]. Patient was undergoing treatment for the same with intralesional corticosteroid and hyaluronidase injections. On intraoral examination, it was found that mucosa appeared blanched with palpable fibrotic bands extending to buccal frenum vestibule involving buccal frenum with a shallow or almost no sulcus in the mandibular left and right distobuccal regions. Various treatment options were discussed, and the patient agreed to the course of treatment described below.
A primary impression was recorded in stock trays with impression compound. The mandibular tray was trimmed from the buccal aspect on the right and left sides, and impression compound was adapted in the mouth in those regions manually. Similarly, the maxillary stock tray was trimmed, and primary impression was recorded.
Maxillary and mandibular primary casts were obtained. For making final impression, carrying the loaded custom tray intraorally would be inconvenient due to limited mouth opening and excessive stretching of the mucosa would cause pain and discomfort to the patient. Thus, it was decided to fabricate a sectional maxillary and mandibular custom tray.
Maxillary impression tray
A 2 mm spacer wax was adapted on the maxillary primary cast and sectioned vertically from the center [Figure 2]a]. The custom impression tray was fabricated using autopolymerizing acrylic resin in two segments. For the first segment, wax spacer was placed on the cast and autopolymerizing acrylic resin was adapted over it. In the midline, the tray was cut in a zigzag manner so that the second segment can be interlocked [Figure 2]b]. On the first segment, a handle was fabricated with acrylic resin in which two tapered die pins were embedded and parallel to each other [Figure 2]c]. After complete polymerization of the first segment, petroleum jelly was applied over the die pins and also over the set acrylic to prevent fusion of the two segments. The handle of the second segment was made in such a way that it fitted over the die pins of the first segment [Figure 2]d].
|Figure 2: (a) Wax spacer adapted (b) sectioned maxillary tray in a zigzag manner (c) handle on the first segment with die pins (d) second handle made on the other segment engaging the handle on the first segment|
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Mandibular impression tray
Unlike maxillary impression tray, the mandibular tray was not sectioned from the midline as the ridge in that region was very thin. Thus, it was decided to split the tray in the thicker region of the right premolar. A 2 mm spacer wax was adapted and sectioned in the premolar region. The first segment was fabricated with autopolymerizing resin, and a tapered die pin was incorporated in the tray such that it was oriented parallel to the ridge and lied over the crest of the ridge [Figure 3]a]. Petroleum jelly was applied over the die pin and the first segment. The second segment was fabricated [Figure 3]b and c].
|Figure 3: (a) Larger mandibular tray segment with a die pin (b) smaller segment of the impression tray (c) locking mechanism of the tray|
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The tray was tried intraorally, fit and extensions were evaluated. Placement and removal of both the segments were practiced. Sectional border molding of both the segments was carried out [Figure 4]a] in conventional manner using low fusing impression compound. Wax spacer was removed from the first segment and relief holes were made. The first segment was coated with tray adhesive loaded with medium body addition silicone impression material and placed intraorally. The second segment coated with petroleum jelly along the midline was placed over to complete tray assembly with anterior lock in place. After setting of the impression material, the two halves of the tray were separated. Excess impression material along the midline was trimmed with sharp instrument [Figure 4]b and c].
|Figure 4: (a) Peripheral molding of the maxillary impression sectioned trays, (b and c) final impression recorded with monophase impression material, (d) mandibular sectional trays joined after the final impression|
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For mandibular impression first the smaller segment impression was made followed by the larger segment. The two segments were then joined [Figure 4]d].
Since the patient was undergoing treatment for OSMF the patient showed slight improvement in mouth opening and thus it was decided to fabricate the maxillary and mandibular complete dentures in conventional manner [Figure 5]a]. Monoplane occlusion was given to allow the patient freedom of movement. Due to compromised conditions the denture was not retentive. Thus, it was decided to reline the maxillary denture with a soft relining material (GC Soft Liner) [Figure 5]b]. No denture adhesive was required for additional retention of the prosthesis after the relining procedure.
|Figure 5: (a) Postoperative view of the patient (b) soft relined denture|
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| Discussion|| |
It is more difficult to insert the impression tray than to remove it from the mouth. When the tray is placed in the mouth, the operator usually stretches one corner of the mouth, making the oral opening still smaller. During removal, the orbicularis oris can be stretched beyond the limit of the patient's normal function as in this situation, the muscle's sphincter shape allows the operator additional maneuverability. 
Many authors have suggested different ways of making an impression in patients with restricted mouth opening. McCord et al.  described a complete sectional denture for a patient with microstomia which was designed in two halves; with the left side fitting into a beveled recess in the right side to give a more accurate location. Both halves were joined rigidly by a stainless steel post that was inserted into three tubes within the complete denture palate. The post, which was removable, was attached to the right maxillary incisor, which served both as a tooth and handle for the post.
Naylor and Manor  described a technique for the construction of a flexible prosthesis for the edentulous patient with microstomia that may be used to perform an oral augmentation exercises to increase the vertical opening.
Al-Hadi and Abbas  described the fabrication of a sectioned mandibular complete denture design for an edentulous patient with surgically induced microstomia. The design of the prosthesis incorporated acrylic resin connections in the form of dovetail with special direction to orient and secure the prosthesis. This design reduced the overall cost and simplified laboratory technique. He also constructed a three-piece, sectional maxillary partial denture and a one-piece mandibular complete denture in a scleroderma patient. 
Watanabe et al.  described a prosthesis, which presented a cast iron-platinum magnetic attachment system applied to sectional collapsed complete dentures for an edentulous patient with microstomia.
As the size of the mouth opening decreases, the difficulty in treatment procedures involved increases. Without surgery, it is very difficult to perform prosthodontic treatment for patients with microstomia, especially when the mouth circumference length is <160 mm. However, surgical enlargement of the orifice must be considered carefully because, if surgical operation is not adequate, a scar may result. 
| Conclusion|| |
Surgical enlargement of the orifice must be considered so that there is enough mouth opening for the fabrication of a complete denture in the conventional way. In this case, the patient was not willing to undergo surgical treatment, and hence it was decided to modify the impression technique by the use of sectional impression trays.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]