ABSTRACT
Aim: Cast partial denture made using altered cast approach creates an environment in which the teeth and the edentulous cells support the denture bases as appropriate as possible, producing a more stable ensemble partial denture.
Background: The tissue of the edentulous ridge in distal extension removable partial denture are prone to be displaced under occlusal pressure. This is due to the displaceability of the mucosa. The difference between your resiliency of the rest of the ridge tissues and the teeth causes disparity of support, that causes the denture to rotate about its distal abutment, inducing heavy tortional strains on one's teeth and possible traumatisation of alveolar ridge. Studies have demonstrated that better support and stability can be achieved in distal extension cases using functional impression along with changed cast technique.
Case description: The next article is a case report of a distal expansion cast partial denture using transformed cast technique for better structure adaptability and stress circulation.
Conclusion: For documenting Kennedy's course I and II edentulous areas, optimum residual ridge coverage with a proper fitting denture platform is required. This reduces tensions, preserving the remaining supporting structures that can be achieved by using altered cast strategy.
Clinical relevance: The modified cast approach allows the rest of the alveolar ridge to be recorded in practical form and pertains to the teeth so that whenever the prosthesis is seated, it derives support together from the teeth and the gentle tissues.
Keywords: distal extension, stress distribution, functional impression, altered cast technique.
BACKGROUND:
The most significant consideration in replacement unit of missing pearly whites for a distal expansion removable incomplete denture as per DeVan's declaration must be "the perpetual preservation of this which remains, rather than the meticulous substitute of that which has been lost. "1-4.
When occlusal causes are applied to distal extension detachable incomplete dentures, the forces must be allocated equally to the abutments and the cells of the rest of the ridge. 2 This can't be accomplished over a master cast made from an individual impression. A dual impression technique is used when a "corrected solid" can be generated which can record and connect the tissue under uniform launching, distribute the strain over as large an area as it can be and effectively delineate the peripheral scope of the denture bottom. 2
Functional impressions are thought as "The impression which documents the proper execution of the rest of the alveolar ridge under some loading whether by occlusal launching, finger launching, specially designed specific tray or steadiness of recording medium. "5 Several methods may be used for registering the alveolar mucosa in its encouraging form. The dual impression techniques are categorised as
1). Physiologic impression techniques.
a). McLean-Hindel method,
b). The practical reline method,
c). The fluid wax method.
2). Selective pressure techniques. 2
According to Leupold6, the functional reline method is achieved following the denture platform has been processed onto the platform. The drawback being it requires a greater amount of occlusal modification after processing of acrylic resin and so it is necessary to change the new denture before providing it to the patient. 6 In like manner conquer this the get good at cast is changed to accommodate the supplementary impression and therefore altered /corrected ensemble is made. 2, 6.
Cast incomplete denture made using the improved cast technique helps create a host in which the tooth and the edentulous cells support the bottom as compatibly as it can be resulting in a more secure denture that enhances the support for the occlusal romantic relationship of the opposing dentition and the removable partial denture repair. 2, 3.
For preservation of the residual ridge, Becker and his acquaintances, critically analyzed the development of removable partial denture and specified six principles because of its design which include a rigid major connector, multiple positive break seating, mesial rests, parallel guide planes, the I-bar clasp design and the transformed cast technique. 7 This system gets the potential benefits associated with reducing the amount of postoperative visits, protecting the rest of the ridges, improving stress distribution, lowering food impaction and decreasing the torquing of abutment teeth resulting in increased patient satisfaction. 8-11.
The following circumstance report will clarify the utilization of altered ensemble technique used in the fabrication of your distal expansion cast partial denture.
CASE DISCRIPTION:
A 60 12 months old guy patient reported to the Section of Prosthodontics Dr. D. Y. Patil Dental College and Hospital, Navi Mumbai with the principle complaint of lacking pearly whites and difficulty in eating.
Extra-oral examination exposed that the individual possessed an ovoid tapered face, with minor prognathism, competent and thick lips. Patient experienced a habit of cigarette smoking since 20 years and so was advised to stop the habit.
Intraoral examination revealed that there is only one teeth 23 left over in the maxillary arch and 31, 32, 33, 41, 42, 43 in the mandibular arch. One's teeth were lost anticipated to caries and periodontitis. (fig. 1, 2)
Radiographs were examined and the treatment was planned. Tooth supported overdenture for maxillary arch and cast incomplete denture for mandibular arch was organized. Diagnostic impressions were manufactured in irreversible hydrocolloid (Imprint, DPI). The impressions were poured using dental stone (type III, kalrock) and casts were procured.
For the maxillary arch, the dog was endodontically cured. Routine resin (DPI) was then used to make a Thimble-shaped coping for the dog which will help in additional retention of the maxillary denture. Principal impression was made using irreversible hydrocolloid (Imprint, DPI) and custom holder was made. The coping was then cemented with zinc phosphate concrete (Dentsply). Border moulding was done with low fusing ingredient (greenstick, DPI) and rinse impression was made using polyether impression material (3M ESPE). Master solid was poured in dental care stone (type III, kalrock).
For the mandibular arch, Diagnostic ensemble were surveyed and cast incomplete framework design was designed. The design included Lingual Dish as the Major Connector, Modified Ladder shapped small connector. RPI system was designed for the rests and guide planes on 33 and 43. Mouth area preparation was done including the arrangements of rest seats on 33 and 43, guide planes on distal of canines. Composite build-up on the mandibular anterior pearly whites was done for better anterior giudance. Impression was made in a custom holder using medium bodied polyether impression materials (3M ESPE) and master solid was poured using oral natural stone (type III, kalrock). Solid partial denture construction was fabricated on the expert cast.
The cast incomplete denture platform was inspected on the professional ensemble and in the patient's mouth for the fit. (fig. 3, 4). The cast partial platform was used as a part of the custom tray for recording the practical impression. Spacer wax (DPI) was designed on the saddle area of the framework and acrylic custom holder was made using Self get rid of acrylic resin materials (DPI). The custom holder was examined in the patient's mouth area for correct expansion.
Border moulding was done using low fusing impression chemical substance (green stick, DPI). Spacer wax was removed to provide space for the wash impression material. Tray was coated with a covering of adhesives so the elastomeric impression material adheres to it. Wash impression made using polyether impression material (3M, ESPE).
The master solid was sectioned into 3 bits by using a hand noticed and the distal edentulous area was removed. (fig. 5). The clean impression made on the construction was placed on the sectioned get good at cast ensuring it seating completely in the rest chair areas. (fig 6).
The entire set up was sealed using energy wax to avoid its dislogement or motion during pouring of the solid. Beading and boxing was done throughout the construction and sectioned get good at ensemble and the impression was poured utilizing a different coloured dental care rock (type IV, kalrock) to tell apart with distal extension areas. The cast thus obtained was the altered cast. (fig. 7). Jaw relationship was registered and teeth layout was done. Try in of the maxillary and mandibular trial dentures was done and dentures were fabricated using Warmth cure acrylic resin (Leucitone, Dentsply). On the denture insertion stage dentures were checked out in the mouth for retention and steadiness. (fig. 9, 10).
Post insertion instructions were given and follow up at the interval of 1month and 3 months was done.
DISCUSSION:
The fabrication of distal extension incomplete denture is a hard activity since it involves taking support from both tissues and one's teeth. Both of these have different amount of movements when causes of mastication are put on them. Thus, the utilization of special impression techniques becomes necessary. However, in some instances, soft tissues displacement is small. As a result, the useful and anatomic contours of the ridge may be nearly equivalent. However, that had not been in cases like this. The decision to utilize dual impression approach along with transformed cast approach was determined in the beginning utilizing a test. Here, first the acrylic denture platform was made on the diagnostic cast and located in the mouth area and finger pressure was applied to the base. There was some amount of lift seen in the framework recommending that there is some soft tissues displacement. So utilizing the dual impression technique we can get an accurate and functionally developed denture boundary and seal. 2, 3, 7, 8. The dual impression used is mentioned for mandibular distal expansion cases due to a limited ridge area, the ability to move of the floor of the oral cavity, to record the strain bearing area and proper peripheral expansion. 2
There are two categories of dual impression techniques mainly the physiologic impression techniques and selective pressure techniques. Physiologic impression techniques track record the tissues of the residual ridge in its functional form by inserting an occlusal fill on the impression holder during impression techniques. The methods will be the McLean-Hindels method; the practical reline method; and the fluid wax method. 2
The dependence on physiologic impressions was first suggested by McLean yet others. He saved the tissue of the rest of the ridge in a functional form and the rest of the teeth in anatomic form. However the disadvantage of the approach being that the dentists could not produce the same efficient displacement generated by occlusal forces because of design of holder being utilized. 2, 12
In response to this shortcoming, Hindel developed his impression procedure by changing the tray because of this which the done impression was a reproduction of the anatomic surface of the ridge and the areas of one's teeth. Disadvantage being that the tissues recorded in this technique continue being in a functional form on a regular basis. This ends in compromised blood flow with adverse tender tissue response and resorption of the root bone. Also sometimes because of this there is presence of premature connections of the teeth replaced that will not be satisfactory to the patients. 2, 13, 14
The Functional Reline strategy and the Liquid wax method where fabrication of the distal extension denture is done before and the new surface is added to the intaglio of the denture foundation afterwards. It could be done in cases where the denture becomes loose. However, as in the last methods this method too, has some challenges mainly, the issues caused by failing to maintain the correct relationship between your framework and the abutment pearly whites during impression making procedure and also failure in achieving accurate occlusal contact following the reline treatment. 1, 2, 3, 15. To defeat this, along with this method corrected solid method was used yielding a much better result. 1, 2, 3, 9, 10, 15
In the mentioned case report we've used the altered ensemble technique along with selective pressure impression treatment. The main good thing about this procedure would be that the construction was ready before we make the ultimate impression and change the master ensemble. So the adaptation of the construction to the teeth and the smooth tissue doesn't change following the last impression. Also the other advantages are,
1. Remarkable balance of the denture basic in distal expansion removable
partial dentures.
2. A confident occlusion which is maintained for extended periods of time.
3. Reduced stress on abutment pearly whites from unfavorable causes.
4. Reduced numbers of post-insertion adjustments. 2, 7, 10
CONLCUSION: Fabrication of any cast incomplete denture for mandibular distal expansion class I circumstances is a obstacle for the prosthodontist. Several functional methods have been proposed for recording the edentulous area and the abutment tooth. An altered solid way of fabricating cast partial denture was found in the above mentioned article. This impression approach helps in registering and co-relating cells of different resiliency. This improves the stableness and support of the denture, leading to optimal load circulation.
CLINICAL SIGNIFICANCE: An modified cast strategy is a way better and faster when compared with other techniques. In this system the cast incomplete framework is maintained ready prior to the recording of functional impression. Because of the correct fit of the ensemble partial framework this system helps in saving the hard and very soft tissues in a much better way. Thus, it could be routinely utilized for the saving of distal expansion area.
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