| Abstract|| |
Context: Overdentures are the choice of treatment for most of them, but the only snag is its cost. In India, the rural areas are still deprived of quality treatment. This manuscript is showcasing a study, which is a cheaper, but effective way to provide the best to the patient.
Aims: The aim of this study was to develop a custom made system, which can be used as an alternative treatment for the management of patients who need overdentures. The primary objective of this study was to provide a cost-effective attachment with the best functional efficacy.
Materials and Methods: The semi-precision attachments were made by using the conventional technique of preparation of post space. The patterns were prepared by using the pattern resin material and the rest of the male and female attachments were fabricated by using innovative methods fulfilling the criteria.
Results: The attachments were successfully used in patients with remarkably good function and comfort.
Conclusion: It was a successful attempt to provide the specialized treatment in affordable cost. There is a need of innovative work to make the sophisticated systems more economical and readily available.
Keywords: Custom made attachments, overdenture attachments, overdentures, semi-precision, tooth supported dentures
|How to cite this article:|
Dable RA, Gaikwad BS, Marathe SS, Badgujar MS, Dole VR. A simplified technique for custom made overdenture semi-precision attachments. Indian J Dent Res 2013;24:622-6
Loss of teeth causes an adverse effect not only on the functional and esthetic efficacy, but also has a big impact on the person's psychological well-being. Patient acceptance for the conventional dentures is less because of various functional and psychological reasons. Many studies have shown that, 20-30% of denture wearers are dissatisfied with the functioning of their dentures. ,,,, Though implants can provide a fixed replacement for natural dentition, due to the cost factor it is not affordable to all.
|How to cite this URL:|
Dable RA, Gaikwad BS, Marathe SS, Badgujar MS, Dole VR. A simplified technique for custom made overdenture semi-precision attachments. Indian J Dent Res [serial online] 2013 [cited 2019 Sep 22];24:622-6. Available from: http://www.ijdr.in/text.asp?2013/24/5/622/123407
Overdenture is the prosthesis, which is fabricated over the existing natural teeth or roots or implants. Retention of a few remaining teeth to support denture will preserve the alveolar bone and the periodontal receptors. The healthy periodontal ligament around the teeth maintains the morphology of the alveolar ridge. 
Overdentures have various advantages like they decrease the pressure on soft-tissue and transmit it to the underlying bone, which increases the ridge integrity, stability and patient comfort. Overdentures have greater retention and stability compared with the complete dentures, which greatly improve the masticatory efficiency. Presence of teeth gives a psychological impact on the person's mind of having natural teeth in his mouth, which adds to the personal confidence. 
Disadvantages of the overdenture treatment include the need for inevitable treatment, which requires additional time and increases costs.  This needs simplification of the techniques that can assure the cost-effective treatment modalities. Practitioners are looking for simplified treatments that can provide cost-effective alternatives to more complex implant prosthodontic procedures. 
Various methods have been innovated to make the overdentures more stable and retentive. Magnets were first used for overdenture retention in 1977. Clinical experience has shown that overdentures preserve alveolar bone and that magnetic retention can be used effectively on tooth roots, which would have a poor prognosis with conventional attachments. Magnets can also be used to retain overdentures against implants as an inexpensive alternative to conventional implant dentures.  Langer and Langer used stud attachments in the abutments to improve the retention and recommended incorporation of cast metal frameworks to prevent base fractures. 
Despite recent developments in dental implantology, the conservative approach to root preservation is still valid. In view of increased root caries rate in the elderly and lax oral hygiene habits of most overdenture wearers, placing protective copings on root abutments, when economically feasible, is the preferred method of treatment. Moreover, it will be an ideal way to solve the psychological as well as economic concerns of patients by providing the overdentures as an alternative to the conventional and implant supported dentures.
Though successful denture therapy is a complex process demanding technical innovations to better the existing modalities in terms of their availability and cost, overdentures are the choice of treatment for most of them, but the only snag is its cost.
The present article describes a procedure where the attachments are fabricated in the institutional laboratory using different simplified techniques and methods, which could provide us a way to avoid the costlier prefabricated sophisticated precision attachments.
| Materials and Methods|| |
Preparation of post space
Extracted teeth (preferably mandibular canines and premolars) were used after the endodontic treatment, for fabricating the attachments. All the teeth to be prepared were mounted on plaster blocks and the canals were prepared for the desired post space. Canal shaping was carried out using low speed Pesso-reamer with sizes varying from #4, #5 and #6 to get an appropriately sized post space. The diameter and sizes were followed as per the standardization given by the "essential dental system," (EDS, USA). Where size one attachment was prepared by using #4 Pesso reamer, size two was prepared by using #5 reamer and size three attachments used #6 reamer. Thus, the reamer sizes implicated the different sizes of the intra radicular preparation.
Pattern fabrication and casting of male component
After the canal preparation, the patterns were fabricated by inserting the resin material inside the canal. This was carried out by preparing a stick of pattern resin that was pressed inside the post space when it was in doughy stage. For preparing the ball attachment, a small plastic bead (size - 1.5 mm) was indexed [Figure 1] using laboratory putty material (addition silicone - putty consistency). This index was used to fabricate the ball attachment by using pattern resin and was attached to the post pattern [Figure 2]. The configurations of ball attachment for all the posts were the same. Casting was carried out by using base metal alloy and the retrieved attachments were air abraded with AlO 2 (50 μm particle size) to remove the residual investment material. Minor voids were removed using round carbide bur and the ball attachment was finished and polished while keeping the post unaltered.
Depending on the size of the post, the surface configurations were accordingly implied. It is the universally known fact that, the larger the diameter of a structure between relatively parallel walls, the greater is the retention. Thus, we divided the attachments into three groups, A, B and C. In Group A, the posts were smaller in size but serrated, thus the post #4 was fully serrated, which could be help in retention in spite of smaller size. To achieve the serrations Goldsmith's die [Figure 3] (which is used to provide threads for screw in ear rings) was used to put the threads on the post [Figure 4]. This enhanced the mechanical interlocking of the cementing medium and increased the surface area of the post. Subsequently for Group B, #5 posts were threaded half way using the same die and in Group C, #6 posts were air abraded with AlO 2 , with a particle size of 50 μm.
Selection of appropriate size and surface treatment can be carried out according to the case requirement.
In order to incorporate the ball attachment in the intaglio surface of the complete dentures, various attempts were made using different methods and materials, out of which three techniques gave satisfactory results.
Firstly, the orthodontic elastic modules were used which could provide the smooth removal and insertion of the denture and also they could act as simple elastic O-ring, which provided the hydraulic seal. These elastic modules also provided the color coding system for different sized attachments, viz. blue - #4, green - #5, yellow - #6 facilitating the identification. These modules were seated over the ball attachments and then replaced in the denture by using autopolymerizing clear acrylic resin that chemically bonded to the denture base.
The purpose of using modules was to serve the mechanical interlocking and a snap on to the comparatively rigid self-cured acrylic over the ball attachment. When the ball is seated in the under surface of the denture it passes beyond the module, keeping it unstretched with the fully seated denture. This extends the life of the modules to 6 months. This method gave optimum retention, ease of fabrication and replacement [Figure 5] and [Figure 6].
|Figure 5: Orthodontic modules and cast attachment with orthodontic module incorporated (figure showing ball attachment and module cased in self-cure clear acrylic resin)|
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|Figure 6: Orthodontic module incorporated in the tissue surface of the denture|
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In yet another technique, a thermoplastic bioplast sheet (2 × 125 mm size) was used, which was adapted over the attachments with the help of Biostar machine [Figure 7]. The attachments were mounted in such a way that only the ball attachments along with extra 1-2 mm space were exposed to ensure the adequate incorporation of the attachment in the sheet. The thermoplastic material caps were cut-off from the sheet by removing the excess material around the attachments. The caps, which served as the female components were then incorporated in the intaglio surface of denture base by using a technique; where the denture fabrication procedure was followed as conventional method until dewaxing of the denture. Prior to the packing of denture base resin, the prefabricated bioplast attachment was adapted over the dewaxed cast. Interlocking grooves were scored on the bioplast attachment to enhance the mechanical retention to the denture base resin.
In the third technique, a long-term soft denture liner material (DENTSPLY AUSTENAL, York) for chair side technique was used. This material is capable of retaining overdentures onto natural teeth, ball abutments or bar connectors.
The shelf life of this material is more than 2 years while it remains soft for 18 months and longer. It was used by mixing powder-liquid in a ratio 2½:1 (as per manufacturer's instructions) and was applied on the intaglio surface of the denture after providing an adequate relief space for the attachments. This method provided an adequate amount of retention and stability to the denture. O-ring, which is an important part of an attachment that provides an optimum hydraulic seal, was prepared by using the rubber tubings.
The attachments fabricated by these methods succeeded in fulfilling the demands of patients by providing them the expected comfort zone. Until the day, about 50 cases have been performed using these attachments where we used 1-4 attachments to support the overlay dentures [Figure 8]. A few of them returned with some complaints related to denture wearing, which was sorted out by doing some minor changes and adjustments. None of the patients encountered major problems. The biocompatibility and application of this system in the field of dentistry is still questionable. Our aim was to provide the best treatment to our patients in affordable price as the cost was the main hurdle for them.
|Figure 8: Custom made semi-precision attachments placed in four abutment teeth for supporting the overdenture|
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| Discussion|| |
Fabrication of a custom made semi-precision attachment is time consuming, but cost-effective. The attachments fabricated here are successfully used for many patients in the institution. The various ways of female components are selected as per the availability of materials and the operator's choice. The root length and diameter determined the selection of attachment. In case of smaller root lengths the full length serrated attachments can be used, while the sandblasted attachments were used successfully with the roots with larger diameter. The size of attachment for the particular root can be selected depending upon surface texture, length and the diameter (size).
Fabrication of custom made precision attachment was attempted approximately three decades ago, when Quinlivan prepared the post space by using the gates and the drills and prepared a pattern in duralay resin on the silver plated die. He prepared the male and female parts separately and joined them together with the additional duralay. The acrylic resin female attachments were seated over the castings with their O-rings.  In the present study, the attachment patterns were first made by using the pattern wax, but it was found to be very fragile and soft, which led the pattern to distortion, also it was time consuming. Pattern resin was used for preparing the patterns, which served the purpose. It is advisable to use the less critical techniques with the easy approach.
Though comparatively, there are fewer studies on semi-precision, custom made stud attachments, the researchers like Berkson used a laboratory made semi-precision attachment in overdentures. As per (according to) him, in order to achieve a satisfactory level of retention and stabilization, we should try to save even the last remaining teeth in the mouth and use them as abutments for overdentures. The attachment, which he fabricated, was spherical shaped stud attachment with a female part made of clasp wire. The attachment was cheaper and easier to fabricate and it provided sufficient retention and stabilization for the dentures.  Nemcovsky et al. in 1990, described a simple technique for fabricating stud overdenture retainers in the form of custom attachment castings with teflon retention discs. This system allows for selective placement of the retention sphere on the root surface and control of retention through the size of the retention sphere. This technique makes the chair side replacement of teflon discs possible. 
Researchers have introduced various simplified techniques for overdentures mainly the bar attachments, which are fabricated more commonly. The intraradicular precision attachments and the bar attachments are the two main attachments, which are used for overdenture retention and stability. The bar can also be custom fabricated in metal or gold alloy and a clip attachment with either prefabricated or custom cast can be used. , Though the prefabricated attachments are more precise, many times they are not preferred due to their cost at first place and various other reasons like, the unavailability of the exact size, which might lead to the absence of accurate fit. Recently, one study described a novel method of fabricating a bar for overdenture that can be used both with prefabricated metal clips and custom cast clips.  This shows that there is need of implementation of innovative techniques, which can provide the better choice of treatment.
Though the custom made attachments lack in the precision, which is possible with the prefabricated sophisticated ones, it is important to serve the purpose to achieve the satisfactory function. The acceptance level of the patients is similar to the costlier attachments or may be it is more here as it is cheaper.
| Conclusion|| |
In India, the rural areas are still deprived of quality specialized treatment modalities only due to their lower socio-economic backgrounds. Owing to the expensive treatment modalities even the clinicians keep away from practicing such procedures, which might keep them away from it is implementation and getting expertise in the special care treatment modalities. Clinicians should make an effort to utilize all the possible resources so that they can apply their knowledge and skill to keep them updated at the expense of patient satisfaction. There is a huge need of innovation to make the sophisticated systems more economical.
| Acknowledgments|| |
All the authors would like to thank the team of clinical and technical staff at SMBT Dental College and hospital who provided their assistance during the study. Also, all the authors would like to thank the Principal and the Chairman of institution to grant permission to conduct this study.
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Rajani A Dable
Department of Prosthodontics, SMBT Dental College and Hospital, Amrutnagar, Sangamner, Maharashtra
Source of Support: None, Conflict of Interest: None
[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8]