Implant-Retained Overdenture for Oral Functional and Aesthetic Rehabilitation - Research Paper Example

Implant-Retained Overdenture for Oral Functional and Aesthetic Rehabilitation Introduction Osseointegration of dental implants is a common dental practice. Osseointegration is the result of biocompatible materials, kind surgical techniques, and appropriate healing combinations. Although many different types of dental implants have been tried and tested, to date, the most successful single-tooth implant has been a screw-shaped device made from titanium. The device is placed into the bone by first drilling a hole and then tapping a screw thread into which the implant is fitted. Since this is designed to stay partially within the bone and does not penetrate it completely, this type of implant is referred to as endosseous (Mellado-Valero et al., 2007). For a successful implant results, selection of patient is an important parameter for the success of the procedure, and these implants may be contraindicated in patients who smoke, who exhibit poor oral hygiene, or who are diabetic (Mombelli and Cionca, 2006). Osseointegration has been studied extensively in general population including the elderly or medically compromised individuals. The success of the endosseous dental implant depends on the formation of a tight junction or interface between the bone and the implant. The outcome evidently at the cellular level is attachment of molecules, fibers, cells, and tissues to the implant surface. Whether this adhesion is produced from a chemical union or tight mechanical attachment is debatable, but it is certain that a strong and intimate contact can be produced (Paquette, Brodala, and Williams, 2006). This bonding is known as osseointegration, and it represents an integration of the implant surface within new bone (Torabinejad and Goodacre, 2006). Few factors known to influence success of osseointegration are adequate healthy bone supporting the implant under an occlusal load, health of the supporting tissue and its attachment to the implant that prevents entry of microorganisms, and absence of systemic disease in the patient. The findings suggest that selection of patient is an important parameter for the success of the procedure, and these implants may be contraindicated in patients who smoke, who exhibit poor oral hygiene, or who are diabetic (Mombelli and Cionca, 2006). In this assignment, from a review of existing and current literature, the evidence will be sought in favor of the hypothesis that for oral functional and aesthetic restorations and rehabilitations in the edentulous patients, an implant retained overdenture is the best available option for offered therapy. Shor et al. (2006) indicated that implant-retained overdentures represent a cost-effective and viable treatment option for edentulous mandible, although success in this process depends on technical skill of the surgeon in that he will have to accomplish accurate 3-D positioning and angulations of implant fixtures. Failure to do so would lead to implant malpoisition leading to malfunction, compromised aesthetics, and loss of structural integrity of the prosthesis (Shor et al. 2006). Shor et al. (2007) in their study again found out that among different treatment options available for the edentulous patients, implant-retained overdentures can be a simple and cost-effective solution, and thus this technique has widespread acceptance. However, there are certain parameters that need to be addressed for better results. These are design of the overdenture, selection of the attachment system, and the optimal techniques for fabrication of the overdenture. It has been indicated that a metal reinforcing framework, prefabricated stock abutment, and resilient attachments are the keys (Shor et al. 2007). Toljanic et al. (1997) cover the background of implant-retained overdentures in edentulous mandibular rehabilitation. These are endosseous implants into the residual and hard and soft tissues of these individuals. In such implants, the patients' desire for function and aesthetics. This concept of implant-retained overdentures was developed to be used with retained abutments of natural roots. The partial dental prosthesis which can be completely removed were reported to have problems with successful function. This functionality can be brought about through use of attachment systems with the implant prosthesis. With the development of technology, the design of these overdentures could be modified through framework fabrication technologies. When an implant-retained overdenture is used, a primary screw retained framework needs to be first milled into an appropriate metal alloy creating a 2-degree tapered wall. A secondary removable superstructure will then be necessary to fix the overdenture, and hence the fabrication technique becomes very important (Toljanic et al. 1997). Pan et al. (2007) recorded subjective experiences of the patients who had dental implants. This study was done through comparison of patient groups who had conventional dentures versus mandibular implant-retained overdentures from the patient perspectives of functioning. The problem with completely edentulous patients is their inability to wear a conventional complete mandibular denture. The implant retained overdentures consist of a screw implant, and they are retained by a cast bar with extra coronal attachments. Their study revealed that 96% of the patients felt very satisfied with their overdentures, and they were very comfortable with it. There were no failures in any of the observed cases during the period of 6 years of clinical observation. The fit of the overdentures was good and comfort levels reported by the patients were high. This study indicated that implants used to retain and support denture improved comfort, and this could have enhances self-confidence of the patients. Oral rehabilitation was successful, and the patients' social interactions considerably improved (Pan et al. 2007). Park (2009) indicated that among several options described for oral rehabilitation of mandibular edentulous patients, particularly for the lower jaw, the osseointegrated implant-retained overdentures have been used with excellent results. Among all the variants, two to four interforaminal dental implants was reportedly showing great success rates (Park 2009). Meijer et al. (2001) highlighted that the main problems with a conventional lower denture are lack of stability and retention. These problems can be successfully avoided with an endosseous implant or a transmandibular implant along with an overdenture. Most of the different forms of these implant systems have very high survival rates in the long run, even to the extent of 100%. The very reason that this system of implants is considered a gold standard may be due to the fact that the patient satisfaction is very high with the overdenture treatment. However, the choice of components also depends on the complication and the needs for aftercare (Meijer et al. 2001). The very reason of the acceptability of such overdentures may be the fact that the bite forces of the people with complete dentures are reduced by 20 to 50% in comparison to the dentate people. It is for this reason the people who wear complete dentures are regarded as oral invalids. The causes for the diminution of the bite force are reduction in individual muscle force, degree and extent of mouth opening, possible tilting of the denture, and pain in the tissues that bear the denture. The tissue discomfort in the lower arch may be due to the hypersensitivity of the mucoperiosteum that covers the edentulous mandibular bridge. It is evident that these pain factors would limit oral functions and hence rehabilitation of these edentulous people. Since the pain may be caused primarily by the area of contact and the degree of support of the mandibular denture by dental implants, and addressing these factors may be critical in improvement of oral function. The fixed implant bridge may thus be a perfect solution of this problem, where studies have revealed significant improvement in the bite force two months following the treatment, which has been demonstrated to increase progressively even up to following 10 years of treatment. Clancy et al. (1991) investigated satisfaction in patients receiving endosseous dental implants as opposed to traditional prosthodontic treatment for missing teeth in edentulous patients. Out of numerous implant systems available, an implant-retained overdenture in retrospectively has been proved to be one of the dependable ways to address the problems of the edentulous patients. Many studies have indicated that such treatments with implant supported bridges made the recipients satisfied in many counts with their prostheses. There were noted positive responses with regard to comfort, efficiency of mastication, phonetics, esthetics, and cleanseability in comparison to completely removable dentures. Additionally, some reports indicated that the self-confidence of the patients improved along with overall dental health. They concluded that patients receiving implant-retained overdentures were generally satisfied with the implant treatment in terms of speech, comfort, esthetics, and function, although there was some discomfort during surgery. However, over time, when healing would be complete, they would complain little discomfort. It is to be noted, therefore, that satisfaction can be correlated with expectations and lack of discomfort out of the treatment, specifically with lack of discomfort. Therefore, it may be deduced that if the expected outcome is close to the perceived result, it would lead to satisfaction, which correlated well with the outcomes of such surgeries, which might have needed more time and expense, and according to most the subjects studied, these were worthwhile (Clancy et al. 1991). Boerrigter et al. (1995) highlighted why edentulous patients are dissatisfied with traditional overdentures. About 15% of the edentulous population in different communities has severe problems with function. Satisfaction with dentures may be influenced by several factors, such as, quality of dentures, available denture bearing area die to significant bone resorption, the quality of dentist-patient interaction, patient experiences with prior dentures, and personality and psychologic health of the patient. The important thing to note is that with the resorption of mandibular alveolar bone over time following placement of denture, the denture bearing area tend to get impaired leading to decrease in denture support, retention, and stability. Many local, general, and individual factors determine the patterns of resorption, but the net long-term result is the eventuality of complete loss of bony alveolar ridge. This affects the outcomes of fixed dentures since the interarch distance is increased as a result. The surrounding soft tissues exert increased influences resulting into destabilization of the prosthesis affecting its retentibility. Consequently, improper prosthesis adaptation may lead to increased discomfort. These changes happen more with an edentulous mandible than with the maxilla since alveolar bone resorption affects the mandible more than the maxilla due to smaller bearing area and a less favourable distribution of the occlusal forces. Therefore, as expected, most of the edentulous people complain more about impaired function of the lower denture. Disordered prosthesis adaptation in this area lead to the experiences related to malfunction or suboptimal function, culminating eventually into interference with proper nutrition and ability to communicate with confidence and ease. Support may be improved with a new set of dentures that fit well or with additional minor surgical procedure for mobilization and optimization of oral soft tissues in order to deepen the denture bearing area. However, quite often the total height of the mandible may be less than required to facilitate this (Boerrigter et al. 1995). Technically, a mandibular implant in an edentulous patient can be used through different strategies. Studies have shown that if a fixed prosthesis is designed to fit between the mental foramina, four or more implants may be placed. In another technique, 2 to 4 implants may be accommodated in this same space so as to able to be retaining a removable overdenture. Regarding support three options are available, namely, mainly mucosa supported, mucosa-implant supported, and mainly implant supported. The mainly implant supported overdenture is the point of discussion here. This rests primarily attached to the suprastructure on the implants. The suprastructure is placed on a minimum of four implants placed intraforaminally. These are connected with a triple bar, which is designed to provide retention and stability to the supported overdenture. This mechanical arrangement facilitates minimal to negligible loading of the denture bearing area during vertical loading. The very proposition that implant-retained overdentures are the gold standards for prosthodontic treatments in edentulous individuals is from the fact that implant-retained overdentures have positive effects on the patients' opinions, and the study of Wismeijer et al. (1997) indicated that in most of the patients the discontent regarding fixed dentures resolved towards a positive difference over time in favor of implant-retained overdentures. The most significant effect could be related to pain caused by mandibular denture, and a self-assessment of pain following implant-retained overdenture was nominal, the reason possibly being improvement in stability and retention of the mandibular denture, sufficient enough to minimize pain and friction on pressure on the underlying mucosa. Moreover, in these patients edentulousness has a social effect, and such implants have been shown to have positive effects on social rehabilitation indicating a socializing effect. The positive effects of these overdentures on the nutrition of these patients may not be ignored. This indicates that improved denture comfort may lead to increased intake of food with a positive bearing on the nutritional status of the patient with comparable results with different forms of implants (Wismeijer et al. 1997). Zitzman and Marinello (2000) dealt with the issue of maxillary edentulousness. The initial practice was to use implant prosthesis with a disregard to the degree of baseline bone resorption. In cases where large bone resorption was present, installation of long standard abutments was routine. It has been observed that in cases of people with mandibular tooth loss, these methods produce acceptable results. Due to open interproximal spaces, the esthetics and functions may be compromised. The basic idea of these prostheses is to improve stability of the denture. The authors have suggested that current scenario suggests that implant supported overdentures are optimal restorative modality for the atrophic maxilla. However, there are certain preconditions which need to be fulfilled for successful results. These are attachment systems, design of the bar, the chosen prosthesis support, and extension of the base of the denture (Zitzman and Marinello 2000). Conclusion Implant-retained overdenture can be considered as the gold standard of dental treatment for edentulous population. This has been very effective in mandible. With this treatment, the root crown ratio is improved, and thus the prognosis of remaining teeth is improved. The biggest problem with the alternative, fixed denture is decay of the underlying bone and wearing of the denture. The other factors are as mentioned, resorption of the alveolar bone leading to residual ridge resorption, loss of stability of the occlusal margins culminating into loss or impairment of masticatory function, and added undermined esthetic appearance. To solve these challenges in the edentulous patients, the osseointegrated implant-retained prosthesis was designed, which not only solved these problems, also had tremendous success rates in terms of durability and satisfaction of the patients. From this point of view, this treatment is ideal, scientifically based, has high success rates with positive outcomes for the patients. Moreover, these also have been shown to improve the quality of life of these edentulous patients, in terms of pain, difficulty eating, appearance, and instability of the denture offered in the conventional treatment. Improvement of these conditions with an implant-retained overdenture through endosseous placement reverts these functional losses that occur such as lack of support, stability, salivary flow, tongue motor control, bite force, and oral sensation. This discussion based on the different studies has indicated that these problems are reversed adequately with the said treatment. Reference Boerrigter, EM., Geertman, ME., Van Oort, RP., Bouma, J., Raghoebar, GM., van Waas, MAJ., van Hof, MA., Boering, G., Kalk, W., (1995). Patient satisfaction with implant-retained mandibular overdentures. A comparison with new complete dentures not retained by implants: a multicentre randomized clinical trial. British Journal of Oral and Maxillofacial Surgery: 133.282-288 Clancy, JMS., Buchs, AU., and Ardjmand, H., (1991). A retrospective analysis of one implant system in an oral surgery practice. Phase I: Patient satisfaction. J PROSTHET DENT;65:265-71.) Meijer, HJA., Geertman, ME., Raghoebar, GM., and Kwakman, JM., (2001). Implant-retained mandibular overdentures: 6-year results of a multicenter clinical trial on 3 different implant systems. Journal of Oral and Maxillofacial Surgery; 59 (11) :1260-1268 Park, J., (2009). Rehabilitation of the edentulous mandible with implant-supported overdenture using ball attachments and healing abutments: A case report. The Saudi Dental Journal; 21, 139– 142 Pan, YH., Ramp, LC., and Liu, PR., (2007). Patient responses to dental implant-retained mandibular overdenture therapy: a 6-year clinical study. Chang Gung Med J; 30(4): 363-9. 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