Extracoronal Resilient Attachments Research Articles

Treatment of Distal Extension Edentulous Arches with Attachment Retained Cobalt Chromium Partial Dentures-A Case Report

Background: The awareness and demand for quality of dental treatment is relatively increasing in recent generation and more so, as far as aesthetics are concerned, along with other functions of the prosthesis. In treating partially edentulous mouth, it requires more attention, principally for esthetics, in design. While achieving the goal, the components which are incorporated in removable partial denture may result in unsightly appearance. Case Description: A 77 year old patient reported to the replacement of his missing teeth for which a conventional maxillary complete denture and cast removable partial denture with precision attachments were planned to construct. Extra coronal resilient attachment was planned to re-claim support and thereby regain of lost esthetics in the mandibular arch. Conclusion: Use of precision attachment has amplified the aspects of retention and particularly, esthetics when compared to conventional removable partial dentures.

Microstrain analysis of implants retained complete mandibular overdenture by using two different attachments (an in vitro study)

Purpose The aim of this work is to evaluate strain analysis of two piece implants retained complete edentulous mandibular overdenture with two different attachment systems bar and clip attachment and extracoronal resilient attachment (ERA + bar) by using strain gauge analysis. Materials and Methods This in vitro strain analysis of implants retained complete mandibular overdenture with two attachments carried out on two completely edentulous mandibular models covered by 2 mm thickness mucosa. Two finished dentures were constructed one denture for each group. Group 1: two implants at canine region with bar attachment. Group 2: two implants at canine region with bar and ERA attachments. Four strain gauges were cemented around each implant, buccal, lingual, mesial, and distal. A 50 N static load was applied on the experimental model in vertical and oblique directions. Strain data of each group was collected tabulated and statically analyzed. Results The result of this study revealed that the difference of microstrain between the two groups was significant as the maximum microstrain recorded was found in group 1 followed by group 2. The oblique forces increase the resulting strain than vertical forces. Conclusion There are different patterns of strain analysis at bone–implant interface between the studied attachment designs, the ERA-bar combination exhibited better strain analysis than bar-clip system

Evaluation of Stress Distribution on Implant-Retained Auricular Prostheses: The Finite Element Method.

The purpose of this study was to evaluate stress distribution around two craniofacial implants in an auricular prosthesis according to the removal forces. Three attachment combinations were used to evaluate the stress distribution under removal forces of 45 and 90 degrees. Three attachment designs were examined: (1) a Hader bar with three clips; (2) a Hader bar with one clip and two extracoronal resilient attachments (ERAs); and (3) a Hader bar with one clip and two Locators. The removal force was determined by means of an Instron universal testing machine with a crosshead speed of 10 mm/minute. All three designs were created in three dimensions using SolidWorks. The applied removal force and the models were then introduced to finite element software to analyze the stress distribution. The angle of removal force greatly affected the magnitude and direction of stress distribution on the implants. The magnitude of stress under the 45-degree removal force was higher than the stress at 90 degrees. The combination of the 1,000-g retention clip and 2,268-g retention Locator exhibited the highest stress on the implant flange when the removal force was applied at 45 degrees. The removal angle greatly influences the amount of force and stress on the implants. Prosthodontists are encouraged to inform patients to remove the prosthesis at 90 degrees and, if possible, use a low-retentive attachment to reduce stress.

Stress-strain distribution at bone-implant interface of two splinted overdenture systems using 3D finite element analysis

PURPOSEThis study was accomplished to assess the biomechanical state of different retaining methods of bar implant-overdenture.MATERIALS AND METHODSTwo 3D finite element models were designed. The first model included implant overdenture retained by Hader-clip attachment, while the second model included two extracoronal resilient attachment (ERA) studs added distally to Hader splint bar. A non-linear frictional contact type was assumed between overdentures and mucosa to represent sliding and rotational movements among different attachment components. A 200 N was applied at the molar region unilaterally and perpendicular to the occlusal plane. Additionally, the mandible was restrained at their ramus ends. The maximum equivalent stress and strain (von Mises) were recorded and analyzed at the bone-implant interface level.RESULTSThe values of von Mises stress and strain of the first model at bone-implant interface were higher than their counterparts of the second model. Stress concentration and high value of strain were recognized surrounding implant of the unloaded side in both models.CONCLUSIONThere were different patterns of stress-strain distribution at bone-implant interface between the studied attachment designs. Hader bar-clip attachment showed better biomechanical behavior than adding ERA studs distal to hader bar.

Prosthetic Rehabilitation of a Patient with Bilateral Cleft Lip and Palate Using Osseointegrated Implants and Extracoronal Resilient Attachments: A Case Report

This case study reports on the prosthetic rehabilitation of a patient with an unrepaired bilateral cleft lip and palate using osseointegrated implants, extracoronal resilient attachments, a combination of metal-ceramic cement-retained fixed partial restorations, and removable prosthesis. Preoperative clinical examination of a 32-year-old woman with bilateral cleft lip and palate revealed a large oronasal communication, hyperplastic soft tissue surrounding the hard palate defect, and a severely resorbed alveolar ridge. A maxillary obturator prosthesis supported by implants and retained with an extracoronal resilient attachment was designed to cover the oronasal communication in the hard palate and fulfill the patient's functional and aesthetic requirements. The patient has been wearing the prosthesis for 1 year. Her speech quality has greatly improved, and her aesthetic and functional expectations have been met.

Effects of rigid and nonrigid extracoronal attachments on supporting tissues in extension base partial removable dental prostheses: A nonlinear finite element study

Resilient (nonrigid) and non-resilient (rigid) attachments are used in extension base partial removable dental prostheses for retention. However, the biomechanical effects of these 2 types of retainers on the terminal abutment and supporting tissues, which may influence clinical treatment planning, have not been compared. The purpose of this study was to compare the mechanical effects of 2 types of extracoronal attachments (rigid and nonrigid) in distal extension removable partial prostheses on the alveolar ridge and abutment tooth periodontal ligament. A finite element model of a human left mandible edentulous arch distal to the second premolar was fabricated. The second premolar was the terminal abutment for an attachment-retained denture. Two types of attachments (rigid and nonrigid) were modeled in the study. For the nonrigid attachment, there was movement between the patrix and matrix component of the attachment, but there was no movement between the 2 component parts for the rigid attachment. Six levels of loading (100, 150, 200, 250, 300, and 350 N) were applied from 3 directions (axial, buccolingual, and mesiodistal) on the central fossa of the first and second molars. Denture motion and stress distributions of denture supporting tissues were observed. Maximum equivalent stress values (SEQV) were recorded for 6 regions (cervical bone, cervical and apical periodontal ligaments, mesial and distal ridges, and mucosa). The data were divided into 2 groups according to the attachment type. Paired t tests were used to compare the values of the 2 groups. Factorial ANOVA was used to test the difference between the loading directions (α=.05). Multiple linear regression was used to analyze the interactions among the factors of region, direction, and level (α=.05). Stress distributions in the rigid and nonrigid attachment models were similar but the magnitudes were different. For all 3 loading directions, significantly different stresses in the alveolar ridge and periodontal tissue of the terminal abutment were found between the rigid and nonrigid groups (P<.05). There were significant differences among the 3 loading directions (P<.05). In the nonrigid group, the stress ratio of the mesial to the distal area was higher than that of the rigid group from axial and mesiodistal loading (P<.05). Linear interactions were found between the direction and level and region and level combinations (P<.05). Movement between the patrix and matrix components increased as loading increased. The most obvious movement of attachment occurred when loading was in the buccolingual direction. Stress on the terminal abutment can be reduced by the use of an extracoronal resilient attachment that allocates more loads onto the distal edentulous ridge. The level of loading influenced the extent of reduction. A resilient attachment with a universal hinge had the most movement when loading was in the buccolingual direction. Interactions were found between direction and level, as well as region and level combinations (P<.05).

Improving retention for extracoronal resilient attachment

Improving retention for extracoronal resilient attachment

A simple method to improve the retention of an extracoronal resilient attachment

A simple method to improve the retention of an extracoronal resilient attachment

Resin bonded attachments for maxillary obturator retention: a clinical report

This clinical report describes the prosthetic rehabilitation of a maxillary defect with an obturator retained by extracoronal resilient attachments. Resin-bonded cast-metal units were used to retain and stabilize the obturator through abutment contour modification, addition of retentive elements, and primary abutment splinting. The resulting rehabilitation conserved tooth structure and satisfied both esthetic and functional needs.

Retention guide for resilient dental attachments

Resilient attachments are widely used in removable prostheses and consist of 2 components. One component is rigid and is either cast or soldered onto the metal framework of the fixed restoration or dowel, while the other is resilient and is usually incorporated into the removable prosthesis. Based on the fabrication processes, the rigid components can be divided into 2 groups: those that are prefabricated by the manufacturers and others that are custom fabricated from preformed patterns. After the prosthesis has been worn for a period of time, retention may decrease as a result of wear on the patrix or matrix components of the attachment. For those fabricated by casting, the accuracy of the attachments may vary as a result of the casting technique, the properties of the metal alloy, and thematerials. As a result, attachment retentionmay vary from what the manufacturers purport. Even with prefabricated attachments, wear will result in a reduction of retention. Replacing the worn components in an attachment-assisted or attachment-retained prosthesis is inevitable. Although manufacturers offer varying levels of retention for attachments, there is little information available about how to make an appropriate selection. This article presents a technique for fabricating a guide to test retention of attachment components. This technique will describe the Stern Extracoronal Resilient Attachment (ERA) (Sterngold, Attleboro, Mass) overdenture attachments; however, the technique is applicable to other attachment systems.

Simplified method for fabrication of a claspless removable partial denture using extracoronal resilient attachment

VOLUME 82 NUMBER 1 A claspless removable partial denture (RPD) with extracoronal resilient attachments (Stern ERA Attachment System, APM-Sterngold, Attleboro, Mass.) can fulfill the esthetic requirement of a partially edentulous patient. Clinically, the difficulties and discrepancies that occur during framework try-in and jaw registration increase because the claspless frameworks often lack of sufficient retention, support, and stability.1,2 This article describes a simple method of fabricating an ERA-included claspless RPD in accordance with conventional RPD design principles and clinical procedures and without complicated operatory and laboratory works.

Removable partial denture fabrication using extracoronal resilient attachments: A clinical report

Removable partial denture fabrication using extracoronal resilient attachments: A clinical report