Implant-supported Overdenture using Resilient Reliner

International Journal of Clinical Implant Dentistry, September-December 2015;1(3):113-118 113

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Implant-supported Overdenture using Resilient Reliner1Siddharth Priyadarshi, 2Syed M Yusuf, 3Ajay Singh, 4Himanshu Gupta

cASE REPORT10.5005/jp-journals-10004-1045

ABSTRACTFixed and removable implant-supported prostheses success-fully address problems associated with complete dentures in edentulous mandibles. Implant-supported overdenture (IOD) improves retention, stability, function, proprioception, and comfort. This case report depicts step-by-step procedure for fabrication of IOD with castable bar and modified resilient reliner. The bar was fabricated from readily available castable bar system, and resilient silicone-based relining was done by using a pickup impression at the time of trial. The shortcom-ings of direct technique are overcome by this procedure. It is a relatively simple and easy technique to produce an accurate prosthesis and devoid of wear and tear of elastic components.

Keywords: Customized bar-supported complete denture, Implant-supported overdenture, Overdenture, Resilient reliner.

How to cite this article: Priyadarshi S, Yusuf SM, Singh A, Gupta H. Implant-supported Overdenture using Resilient Reliner. Int J Clin Implant Dent 2015;1(3):113-118.

Source of support: Nil

Conflict of interest: None

INTRODUCTION

The loss of teeth results in adverse esthetic and biome-chanical sequel “the edentulous predicament.” Three treatment options are available, which include complete denture, implant-supported overdenture (IOD), and implant-supported fixed denture. The choice between use of different treatment modalities depends on ridge condition, soft-tissue contour, and patient compliance. The use of endosseous dental implants as a treatment modality for mandibular edentulism is well docu-mented for both fixed and removable prosthodontic reconstructions.1,2 The placement of implants enhances the support, retention, and stability. Both fixed and removable implant-supported restorations successfully address problems associated with complete dentures

in edentulous mandibles.1,3 Ideally, a prosthesis that is completely supported, stabilized, and retained by implants should be designed when the soft- and hard-tissue contours of the patient demand the use of an over-denture instead of a fixed restoration, as the thickness of flanges can be managed only in removable prosthesis. In such circumstances, an IOD is a cost-effective and good treatment modality. Implant-supported overdentures are the restoration of choice in complex restorative situ-ations where facial support is needed and are relatively simple to construct; they can restore both dental and alveolar tissues and are economical and able to satisfy the esthetic demands of complex restorative situations. Various multicenter studies were carried out on clinical performance of IOD and results showed that success rate was approaching near to 100%.4-6 Implant overdentures vary in design, according to the method of attachment and amount of support to be derived from implant and ridge mucosa.7 In general, IOD attachments can be clas-sified as studs, magnets, and bars. No absolute rules have been established for overdenture case design with dental implants while the determinants for attachment selection include type of prosthesis, the length of the bar, the number and inclination of implants, dexterity, expec-tation, and financial capabilities of the patients.8 Out of various attachment systems, bar attachment along with clips/Molloplast gives improved retention and stability, allowing splinting of implants. A variety of bar designs exist, including prefabricated, custom-made, and cast-able bar. Incorporating an attachment system of choice is another advantage of using this bar design. There are no scientific data that support the use of one attachment system over another one.9,10

In this case report, a patient was presented with limited denture stability and retention. The prosthetic rehabilitation consisted of mandibular IOD with a cast-able bar and resilient heat cure silicone-based reliner attached to denture with indirect technique. The design incorporated use of Molloplast-B for retention.

CASE REPORT

A 74-year-old, completely edentulous male patient reported to our outpatient department of prostho don-tics, with the chief complaint of ill-fitting lower denture. The patient had trouble while eating, and his speech was impaired due to constantly dislodging lower denture.

1,2Postgraduate Student, 3Professor and Head, 4Reader

1-4Department of Prosthodontics, Sardar Patel Post Graduate Dental College, Lucknow, Uttar Pradesh, India

Corresponding Author: Siddharth Priyadarshi, Postgraduate Student, Department of Prosthodontics, Sardar Patel Post Graduate Dental College, Lucknow, Uttar Pradesh, India, Phone: +919453325947, e-mail: spriyadarshi140@gmail.com

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Figs 1A and B: (A) Maxillary edentulous ridge, and (B) mandibular edentulous ridge

Figs 2A and B: (A) Implant placement in anterior mandibular region, and (B) post surgical OPG of implants placed in interforamina region of A, C and D (Misch classification)

A

A

B

B

Diagnosis and Treatment Planning

Treatment options:• Reliningoflowerdenture• Conventionalnewupperandlowerbalanceddenture• Implantsupportedprosthesis

– Removableprosthesis– Fixed prosthesisClinicalandradiographicevaluationrevealededen-

tulous maxillary and mandibular arches (Figs 1A and B). The posterior mandibular ridges exhibited bone loss and deficiency in height and width. Diagnostic impressions were made. Diagnostic teeth setup at appropriate vertical dimensions was done to assess the available restorative space, jaw relationship, and teeth position for the best esthetic and functional results. Based on the diagnostic workup, a class I skeletal relationship existed and 13 mm of restorative space was available. After discussing the clinical and radiographic findings with the patient, the following decisions were made: Placement of three implants in the interforamina region, i.e. A, C, and D (Misch) of the mandible and fabrication of maxillary denture along with a bar-supported mandibular over-denture as a definitive prosthesis.

Surgical Implant Placement

Optimal surgical implant positioning is essential for the success of implant-supported restorations. A detailed

description of the proposed implant positions and dis-tribution was considered prior to surgical procedure, and a surgical guide was fabricated from the diagnos-tic workup. The position, distribution, and number of implants to be placed were determined based on the predesigned restoration, the available ridge dimension, and the limitation of the anatomical structures. In stage 1 surgery, three implants (3.75 × 10) (Adin Dental Implant System Ltd; Afula, Israel) were placed in the anterior mandible at #41, #44, and #32 regions (Figs 2A and B). A second stage surgery was carried out to place healing abutments 3 months after the primary implant surgery. Healing abutments were fastened to the implants to allow undisturbed soft-tissue healing. The patient’s pre-existing denture was relined (Visco-gel Temporary Soft DentureLiner;DentsplyCaulk,USA)toaccommodatethe healing caps. The intaglio surface of the denture was relieved, to allow enough room for the application of the soft-tissue conditioning material while avoiding direct contact between the denture acrylic and the healing abut-ments. The denture was finished, polished, and inserted into the patient’s mouth.

Prosthodontic Procedures

Accurate transfer of the implants position to the master cast is a primary requirement to ensure a passive fit restoration. An impression procedure that implements

Implant-supported Overdenture using Resilient Reliner

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a ridge splinting of the impression coping is therefore recommended.11,12 A primary impression was made with irreversible hydrocolloid material (Tropicalgin; Zhermack,BadiaPolesine,Rovigo,Italy)(Figs3AandB).

For an accurate master impression, impression copings were mounted on the primary cast implant analogs and splinted with autopolymerized acrylic resin (GC PatternResin; GC Corp, Tokyo, Japan). The resinsplint then sectioned vertically between the impressions copings to allow accurate reassembly in the patient’s mouth. A custom tray was fabricated with occlusal window openings to allow individual access to each impression coping. At the time of making the master impression, the open tray impression coping with the acrylic index was brought to the patient’s mouth, screwed to the corresponding implant, and reassembled with the additionofanautopolymerizedresin(GCPatternResin;GCCorp,Tokyo,Japan)(Fig.4).

The resin was allowed to reach final setting and a rubber base impression (Aquasil Ultra XLV; DentsplyCaulk,USA)wasmadewithlightbodymaterial(Fig.5).

The guide pins were loosened and the impression was removed from the patient’s mouth. The implant analogs (Adin Dental Implant Systems Ltd; Afula, Israel) were placed and the impression poured in die stone (Diestone; Kalrock Kalabhai Karson Pvt Ltd, Mumbai, India). An autopolymerized acrylic resin record base

wasthenfabricatedbysaltandpeppertechnique.Recordbase was stabilized over the healing abutments with the help of Addison silicone material (Aquasil Ultra XLV;DentsplyCaulk,USA).MaxillarycastwasmountedonBioart-2000articulatorwithfacebowtransfer.Jawrelationwas recorded by manipulating the patient’s mandible into a centric relation position. The mandibular cast was then mounted on a semiadjustable articulator and evaluated again. A modified occlusal concept given by Misch13 was incorporated, which included raised occlusal plane to upper one-third of tragus, medial positioning of teeth relative to retromolar pad and lingualized occlu-sion.14 Teeth arrangement was completed and tried for patient’s approval (Fig. 6).

Esthetics, phonetics, and vertical dimension of occlu-sion were evaluated. An occlusal silicone tooth position index incorporating the incisal edges and the occlusal half of the mandibular denture teeth setup was fabri-cated.15 The occlusal silicone index was cut exactly in the center by joining incisal edges and central grooves of molars. Each half of index would be used during bar fabrication procedures to facilitate accurate repositioning of the denture teeth in relation to the master cast.

Bar Fabrication

• Toothpositionindexwasusedtodetermineavailablevertical height for bar.

Figs 3A and B: (A) Primary impression in irreversible hydrocolloid of maxiilary arch, and (B) primary impression in irreversible hydrocolloid of mandibular arch

Fig. 4: Splinting of impression posts Fig. 5: Mandibular final impression

A B

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• UniversityofCalifornia,LosAngeles(UCLA)abut-ments were screwed to the master cast implant analogs and cut to appropriate height.

• Acastablebar system (OTBarMultiuse;Rhein83,NY, USA), consisting of castable bar, castable box,positioned clip, and retentive clip, was used. The bar was attached to abutments and casted (Fig. 7).The amount of the available restorative space, hygiene

requirements, and biomechanical principles govern the developed bar dimension.• Castableboxesweretheninvestedandcastedtoget

metal superstructure.• Thebarwasfinishedandpolishedandcheckedin

patient for passive fit (Fig. 8).After verification of passive fit, overdenture was

fabricated.

Placement of Completed Prosthesis

• Finishedbarwasplacedinpatient’smouthandtheabutment screws torqued down to 32 Ncm according to the manufacturer’s directions (Fig. 9). The screw openings were blocked by gutta-percha points.

• Resilient reliner (Molloplast-B) was applied on theintaglio surface of the denture (Fig. 10).

• Thedenturewascheckedinpatientforproperextensions.• Theintimatefitoftheintagliosurfaceofthedentureto

the bar provided enough retention for the prosthesis during this procedure (Fig. 11).

Fig. 6: Try-in of trial denture bases Fig. 7: Castable bar attached to abutments

Fig. 8: Finished bar Fig. 9: Bar screwed to implant

Fig. 10: Molloplast-B applied on the intaglio surface of the denture

• Centricrelationrecordswereobtainedandaclinicalremount for final occlusal refinement was done.

• Home-care instructions were given to the patient,and he was then trained for insertion and removal of his new denture. At the 1-week follow-up, the patient was satisfied with the amount of the retention and stability provided with new denture (Fig. 12).

DISCUSSION

Thorough evaluation and treatment planning that addressed the patient’s needs, expectations, clinical, and radiographic findings resulted in a provision of the final

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Fig. 11: Denture insertion Fig. 12: Recall visit

restoration design that met our patient’s functional and esthetic needs. The need to have an overdenture design of superior stability and retention was recognized at an early stage of the treatment plan, allowing implant placement with optimal distribution. The bar-supported overdenture is an advantageous option as it got several advantages of implant splinting—improved retention and stability, reduced forces on implant, less screw loos-ening and crestal bone loss, also laboratory can position attachments parallel to each other. Incorporating resilient reliner provided the patient with sufficient retention to prevent vertical movement of the denture.

Modifications were carried out in the prosthodontic protocol to help the case:• Splintingofimpressioncopingforaccurateposition-

ing of implant analog over final impression.• Fabrication of stabilized record bases by adding

Addison silicone.• Amodifiedocclusalschemewasincorporatedtosta-

bilize the weak component of removable prosthesis (maxillary denture).

• Fabricationofocclusal indexforteetharrangementmodification and vertical height determination.

• Theimplantplacementinthisparticularcaseisdoneat A/C/D regarding the bone condition. However,the bar was fabricated from A to E to make it more bilaterally symmetrical and also to strengthen the whole attachment assembly as a unit.

• The option of using Molloplast-B is to reduce thewear and tear of elastic components like clips used otherwise and also enhance the retentive surface area on the bar.

• Resilient reliner are much better than clips asthese are really long-lasting and time-tested. This is Molloplast-B which is silicone-based permanent resilient reliner, if required it is to be changed after 4 to 5 years.

• Here bar attachments were preferred over locatorattachments because locator attachments are non-splinted, and they provide only retention, where as bar attachments provide retention, stability, and support as they are splinted.

The McGill Consensus Statement (2002)16 recom-mended two implants to support a mandibular denture as a minimum standard of care, citing the poor fit and function of many mandibular dentures that were not implant supported. In 2007, some of the authors of the McGill Consensus Statement17 attempted to evaluate this question by reviewing the literature. They found that there was no evidence to support fixed or removable being superior. In 2011, De Kok et al18 published a pilot study comparing fixed vs removable dentures in the mandible. Their findings suggested equivalence; patients were equally happy and functional with either an over-denture or a fixed denture. This was further evaluated in 2014 by Oh et al who published a prospective-controlled study comparing fixed implant-supported prostheses, removable implant-supported prostheses, and complete dentures. They found that implant-supported prosthe-ses, fixed or removable, were equivalent and superior to conventional dentures for improving oral-health-related quality of life. The same was true with patient satisfac-tion; patients were equally pleased whether or not their prosthesis was fixed or removable. Therefore, the choice of whether a patient should have a fixed or removable prosthesis is a patient-specific one, dealing more with psychology and cost, rather than superior esthetics or function.

Various types of attachment systems are currently available to restore IOD. The IOD attachment systems used are stud or ball, cast bar and clip, locator (Zest Anchors,Escondido,CA,USA),orresilientattachmentand magnet. Clinicians have selected IOD attachmentsystems based on factors, such as durability, patient demand, cost-effectiveness, technical simplicity, and retention.19 The successful outcome of IOD therapy is well documented, and different types of attachment systems have been compared regarding implant survival, marginal bone loss, soft tissue, retention, stress distribu-tion, maintenance, and complications. Many systematic reviews have concluded that type of attachment system does not significantly influence the factors associated with the overall success of implant overdenture therapy.

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However, the decision-making process to prescribe certain types of attachment system still remains unclear. A review by Andreiotelli et al20 in 2010 has suggested that clinicians seem to use attachment systems based on preference, rather than scientific evidence, due to the high success rate of implants, regardless of attachment system.

CONCLUSION

The clinical and laboratory steps for fabricating an IOD with a castable bar and resilient reliner (Molloplast-B) have been presented in this article. This is cost-effective, simple, and provides an exceptional stability and excel-lent retention. Although the suggested method involves additional laboratory procedures during fabrication, it offers several advantages of the indirect techniques.

From the evidence presented in the article, it can be summarized that the edentulous patient restored with an implant-supported mandible overdenture experienced more satisfaction with their prosthesis as it improved masticatory ability and nutrition along with improvement in psychosocial aspects of life. Prospective randomized studies with longer follow-up periods are required; it can also be concluded that the patients restored with an implant-supported mandible overdenture had expansive improvement in quality of life.

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