PROSTHODONTIC REHABILITATION OF PATIENT WITH FLABBY RIDGES USING TWO DIFFERENT IMPRESSION TECHNIQUES: A CASE SERIES

Prosthodontics

Dr. Bisma Reyaz (P.G. Student), Dr. Nivea Verma (P.G. Student), Dr. Manesh Lahori (HOD & Dean), Department of Prosthodontics, K. D. Dental College & Hospital, Mathura.

INTRODUCTION

Complete dentures are artificial substitutes for living tissues that have been lost. The dentures must replace the form of living tissues as closely as possible. Most importantly, the dentures must function in harmony with the remaining tissues that both support and surround them.

Epidemiological studies of the edentulous population showed that most patients with complete dentures have pathologic tissue changes that require treatment and these changes have little relation to a patient’s perception of denture success or personal oral health status. The success of a new denture requires the support of healthy tissues. Abnormalities, whether they are local, mechanical, or systemic in origin, must receive proper diagnosis and treatment. A comprehensive clinical examination and accurate dental history are essential to identify problems and take necessary corrective action for Successful recovery of abused tissue which requires tissue conditioning.

One such condition is flabby ridges which shows hyperplastic growth of soft tissue that replaces alveolar bone. Flabby ridges, poses difficulty and may intensify complaints of pain or looseness of complete denture resting on them. Its prevalence is about 24% in edentate maxillae and in 5% of edentate mandibles. As the flabby tissues are easily distorted while impression making steps, the dentures fabricated on such foundations are often compromised in its retention and stability. Several treatment modalities offered in such patients

  1. surgical removal of fibrous tissue prior to conventional prosthodontics,
  2. implant retained prosthesis
    1. fixed,
    2. removable,
  3. Conventional prosthodontics without surgical intervention

A particular problem is encountered in the conventional impression making if a flabby ridge is present within an otherwise “normal” denture bearing area. If the flabby tissue is compressed during conventional impression making it will later tend to recoil and dislodge the overlying denture.2 Thus, over the years, several impression techniques have been suggested for the impression of a flabby tissue ridge which will support the flabby tissue but at the same time will not displace it. Prosthodontic literature has documented various impression techniques for overcoming the problem of the flabby ridge. This case report depicts the use Double spacer impression technique using polyvinyl siloxane (medium body) to fabricate a denture.

IMPRESSION TECHNIQUES FOR RECORDING FLABBY TISSUE

Numerous techniques has been described in literatures for recording flabby ridges. These include the following:

  1. Liddledow technique (1964) In this technique, two separate impression materials are used in a custom tray using plaster of paris over flabby tissue, and zinc oxide eugenol over normal tissue.
  2. Crawford & Walmsley They used two different materials and two custom-built trays, which was similar to Liddledow?s technique.
  3. Osborne (1964) Special impression technique whereby two overlying impression trays were used for recording maxillary arches with displaceable anterior ridges. This technique aimed to maintain the contour of the easily displaceable tissue while the rest of the denture bearing area is recorded.
  4. Watsons (1970) described the “window technique” Here a custom tray is made with window over flabby tissue. The window minimized the movement of the flabby ridge tissue during function. This technique involves recording of definitive impression in two steps. A muco-compressive impression of normal tissues is first made using the custom tray and zinc oxide eugenol impression paste. In the second stage, a low viscosity mix of plaster of Paris is painted over flabby tissue through the window.
  5. Zafarulla khan technique (1981) The technique is similar to Watson?s window technique. The custom tray is modified with posterior handles and anterior opening for unsupported tissue. The tray is painted with an adhesive and regular body impression material is used for the final impression. The excess material is trimmed to the outline of the aperture. The unsupported movable tissue is recorded by brushing on impression plaster
  6. Jone D Walter technique The technique is similar to Watson?s window technique.He recorded the healthy denture bearing tissues with zinc oxide eugenol paste and the displaced fibers of tissue with impression plaster
  7. Devlin (1985) Modified Osbornes approach by using a locating rod that as positioned in the center of the palatal tray, but proclined to allow the second special tray impression to be guided in an oblique upward and backward direction to envelope the palatal tray. The palatal tray will accurately locate the second part special tray using a stop, thereby allowing for a pre-planned even thickness of impression material.
  8. Magnusson et al. (1986) used zinc oxide eugenol paste for normal tissues and a plaster material for flabby area into a custom tray.
  9. William H Filler He has described a technique using two impression trays. The second tray is accommodated on the first tray. In the first tray, light body impression material is used as the corrective wash material. Adhesives are painted over the areas not covered by the first impression in second tray and impressions are recorded. The two trays are held tightly together until the impression sets and the final impression is removed as a single unit.
  10. Hobkirk technique In this technique, a single custom tray is used. The secondary impression is recorded with heavy bodied addition silicone. The areas of movable tissues are cut out and relief holes are made. Wash impression is recorded using light body impression material.
  11. The Massads technique This technique makes final impression in single visit by eliminating the need to fabricate custom tray from cast obtained from preliminary impression. An edentulous, perforated stock tray is selected according to patient?s ridge size and width. Tissue stops are created using heavy viscosity impression material. For this, spherical pieces of material are placed in one in anterior region, one in each posterior region, and one in palatal area (maxillary tray). Then the tray is placed in patient?s mouth allowing for 2-3 mm of space. The stops were then allowed to set in patient?s mouth. This procedure is followed by border molding using heavy viscosity impression material. After evaluating the extension of the border details, final impression is recorded using two different viscosity materials. Heavy body impression material is used over tuberosity region and light body impression material over the remaining tissue surface Different viscosities of impression material were selected so as to record the load bearing area in the functional state and the other areas that is flabby tissue and relief areas, under minimal displacement.
  12. Allan Macks Splint Method It is used if tissues are excessively and exceptionally flabby. Loosely fitting tray or a special tray made with heavy relief over the flabby area is taken. Plaster is mixed and applied over the flabby area to a thickness of about 3 mm and is allowed to set. Tray is filled with second mix of plaster and the impression is made. The initial coating of the flabby areas thus acts as a „splint. It gets removed with the second impression
  13. Lynch & Allen technique (2003) In this technique, impression compound is applied to a modified custom tray. The thermoplastic properties of this material are then manipulated to simultaneously compress the „normal tissues, while avoiding displacement of the „flabby tissues using the same material and impression tray. Over this manipulated impression compound, a wash impression with zinc-oxide and eugenol is made. The buccal shelf area (primary stress bearing area) acts as a stopper for the tray in the final impression procedure. The remaining borders of the tray will be recorded by selective pressure technique using green stick compound. The final impression will be recorded using a monophase impression silicone (its thixotropic property ensures adequate flow under pressure).
CASE REPORT-1
CLINICAL PROCEDURE

A 50-year-old female patient reported to Dept.of Prosthodontics for replacement of missing teeth. The patient had a history of wearing maxillary and mandibular complete dentures since past 5 years. Her chief complaint was the wearing away of the denture teeth, and denture loosening. By intraoral examination, a completely edentulous maxillary arch with flabby tissue existing in the maxillary anterior region was observed.

Figure 1:Edentulous mandibular arch

Figure 2: Completely edentulous maxillary arch showing flabby tissue

A primary impression of the upper and lower arches was taken with alginate (Neocolloid; Zhermack) in the edentulous trays. The impressions were poured with dental plaster and the displaceable tissues were identified on the cast. On the maxillary cast, an “I” shaped spacer was applied along the mid palatine raphe using modelling wax with additional relief given in the flabby area from canine-canine region. A maxillary custom tray was fabricated using clear autopolymerising acrylic resin (RR self-cure acrylic resin, Dentsply, India) covering the tissues except the area that was flabby. Over the “open” area of the tray another “supporting tray” of clear acrylic was made thus covering the flabby ridge. A mandibular custom tray was fabricated with autopolymerising acrylic. For maxillary Clear acrylic resin was preferred for tray fabrication as tissue blanching underneath the tray could be easily evaluated, thereby making it easier for the operator to relieve pressure spots on the tray .The handle was placed in the palatal portion of the maxillary tray to ensure visualization of the underlying tissues through the clear acrylic tray and also to facilitate uniform distribution of pressure during impression making

Final Impression of the Lower Ridge. There was no flabby tissue found in the mandibular arch so The borders of impression were recorded by selective pressure technique using green stick compound (Pinnacle tracing stick, DPI, Mumbai, India) and spacer wax was removed and holes were drilled in the tray and a final impression using zinc oxide eugenol was made.

Figure 3: Mandibular custom tray with spacer removed

Figure 4: Final impression made with zinc oxide eugenol

Final Impression of the Upper Ridge. The maxillary borders were recorded by selective pressure impression technique using green stick compound. The relief wax was removed and multiple holes were drilled in the “supporting tray.” Placement of multiple relief holes was done to ensure prevention of pressure buildup in the flabby area thereby leading to inadvertent tissue compression. Tray adhesive was applied and a final impression using monophase (medium body) (Aquasil LV Monophase, Dentsply Caulk) addition silicone was made (Figure 11). A monophase impression material was preferred as it has the desirable thixotropic property thereby ensuring adequate flow under pressure.

Figure 5: Maxillary custom tray with spacer removed and multiple holes placed in area of flabby tissue

Figure 6: Completed secondary impression with monophase polyvinylsiloxane material.

Figure 7: Fabricated prosthesis

Subsequently, conventional treatment procedures were followed to deliver complete denture prosthesis

CASE REPORT-2
CLINICAL PROCEDURE

A 55-year-old female patient reported to Dept.of Prosthodontics for replacement of missing teeth. The patient had a history of wearing maxillary and mandibular complete dentures since past 6 years. Her chief complaint was denture loosening. On examination, it was found that there was an area of flabby tissue in the maxillary anterior region extending from the canine region from one side to the other (Figure 8)

Figure 8.Completely edentulous maxillary arch showing flabby tissue

A primary impression of the upper and lower arches was made with alginate (Neocolloid; Zhermack) to record the tissues in a minimally displaced form. The impressions were poured with dental plaster and the displaceable tissues were identified on the cast. Custom trays were fabricated in autopolymerizing resin(RR self-cure acrylic resin, Dentsply, India) with a spacer of modeling wax with 1?mm thickness. A spacer thickness of 2 mm is adapted in the area of flabby ridges (double spacer). Border molding was carried out using the sectional method for the maxillary arch with greenstick compound (DPI Pinnacle, Tracing Sticks Dental Products of India, Ltd.). The displaceable tissue was marked intraorally with indelible pencil, and this marking was transferred on to the custom tray. A window was cut through the custom tray exactly corresponding to the area of the flabby tissues in the anterior maxilla (Figure 9)

Figure 9. Window cut through the custom tray corresponding to the area of the flabby tissues.

The impression was made with zinc oxide eugenol paste. The impression was not removed from the mouth, and light body polyvinyl siloxane (3M ESPETM II GARANT) was syringed on to the flabby tissues (Figure 10) exposed through the window, and the maxillary impression was completed (Figure 11).

Figure 10. Light body polyvinyl siloxane syringed on to the flabby tissues

Figure 11. Completed maxillary impression

There was no flabby tissue found in the mandibular arch so the borders of impression were recorded by selective pressure technique using green stick compound (Pinnacle tracing stick, DPI, Mumbai, India) and spacer wax was removed and holes were drilled in the tray and a final impression using zinc oxide eugenol was made (Figure 12).

Figure 12. Completed mandibular impression

Now, both the impression are beaded, boxed and poured properly. Complete denture is fabricated in conventional manner. (Figure 13)

Figure 13. Fabricated prosthesis

DISCUSSION

Various techniques have been recommended and as to whether a muco-displacive technique which compresses the mobile tissue aiming to achieve maximum support from it or whether a muco-static technique with the aim of achieving maximum retention should be employed. The current paper describes a simple technique to record flabby tissues in their un-displaced state using readily available clinical materials like polyvinylsiloxanes in varying consistencies. The advantage of choosing monophase impression material is that, due to the inherent nature of the material, different consistencies can be achieved by varying the pressure applied on the material during mixing. Though literature has reported earlier techniques for recording flabby tissues using polyvinylsiloxanes, monophase impression material is used in this technique.

REFERENCES
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