The Effect of Denture Cleansing Solutions on the Retention of Yellow Hader Clips: An In Vitro Study

PURPOSE: To evaluate the retention of yellow Hader clips after exposure to various denture cleansers. METHODS: Seven groups of 18 yellow Hader clips each were soaked for the equivalent of 6 months of clinical use in the following denture cleansing solutions: Polident Regular, Polident Overnight, Efferdent, 5.25% Sodium Hypochlorite (NaOCl, 1:10 dilution) 15 min/day, NaOCl (1:10 dilution) 8 hours/day, water and dry (control) group. A Universal Testing Machine, set at a crosshead speed of 2 in/min, pulled each clip once, and the peak load-to-dislodgement was recorded and used as a measure to reflect changes in the retention of the Hader clips. Data were analyzed by a one-way analysis of variance followed by Tukey's HSD test. A p value < or = 0.05 was considered significant. RESULTS: Denture cleansing solutions affected the retentive values of yellow Hader clips (F= 6.102, p< or = .0001). Sodium hypochlorite solution, 15 min/day for 6 months, caused an increase in the retentive values of the clips tested with a mean peak load-to-dislodgement of 22.63 +/- 1.29 N. In addition, clips soaked in water showed no difference in retentive values when compared with all other groups. Furthermore, Polident Regular, Polident Overnight, Efferdent, and NaOCl (8 hours/day) had no effect on the retentive values of yellow Hader clips. CONCLUSION: This in vitro study demonstrated that the retention of yellow Hader clips used in implant overdentures is unaffected when soaked in commercial effervescent denture cleansers (Polident 5 Minute, Polident Overnight, and Efferdent) for six simulated months. Sodium hypochlorite statistically increased the single-pull retentive values of the clips, an effect that may not be beneficial. Increased retentive values may be associated with reduced durability of clips; further research is needed to address this issue.     

Retention of maxillary implant overdenture bars of different designs

STATEMENT OF PROBLEM: The specific degree of retention for overdenture attachments is unknown in relation to design, location, and alignment to supporting dental implants. PURPOSE: The purpose of this study was to evaluate the initial retention characteristics of 5 implant maxillary overdenture designs under in vitro dislodging forces. MATERIAL AND METHODS: A simulated edentulous maxilla was fabricated with 4 screw-type 3.75 x 13-mm implants anteriorly. Five overdenture designs with the following attachments were evaluated: 4 plastic Hader clips with an EDS bar; 2 plastic anterior Hader clips with an identical EDS bar; 2 Hader clips with 2 posterior ERA attachments; 3 Zaag attachments on a bar; and 4 Zaag attachments with no bar. Overdentures were fabricated with full palatal coverage. Each design was subjected to 10 consecutive retention pulls on a universal testing machine. Data were subjected to analysis of variance and t tests to determine differences. RESULTS: The highest average value after 10 pulls was 19.8 lb for the combination ERA and Hader clip design. The lowest retentive values were recorded for the 2 and 4 Hader clip designs (5.08 +/- 0.89 lb and 5.06 +/- 0.67 lb, respectively). Retention decreased over the course of consecutive pulls for all designs, especially for the most retentive designs. The smallest retention decrease occurred with the least retentive designs. CONCLUSION: The results of this in vitro study suggest that the precise selection and placement of attachments may affect the clinical success of maxillary implant-retained overdentures.     

The influence of interimplant distance and attachment type on the retention characteristics of mandibular overdentures on 2 implants: initial retention values

PURPOSE: This in vitro study aimed to investigate the influence of (1) the interimplant distance and (2) the type of attachment on the retention of mandibular overdentures on 2 implants. MATERIALS AND METHODS: Three stone casts were fabricated, each with 2 implant analogues embedded at distances of 19, 23, and 29 mm apart. Three different interchangeable mandibular overdenture attachments were secured onto the analogues: Hader bars, ball abutments, and stainless steel keepers for new generation neodymium-iron-boron magnets. In total, 45 groups of paired attachments were tested for initial vertical peak tensile load at the 3 interimplant distances. RESULTS: Interimplant (interclip) distance played a significant role only in the retention produced by the Hader bar/red clip configuration. At 19 and 23 mm, the ball/socket attachments were statistically more retentive than the yellow clips, white clips, and magnets, but not compared to the red clips. At 29 mm, the ball abutments showed statistical superiority compared with all other attachments. Mean clinical intercanine distance for conventional full dentures was 22.88 mm. CONCLUSION: Interimplant distance can affect the initial retention of mandibular overdentures on 2 implants depending on the type of attachment used. For a predetermined interimplant distance, attachment performance varies greatly.     

Special technique for attachment incorporation with an implant overdenture

The Hader bar system is a popular bar and clip concept because of its 20-degree clip rotation, simplicity, and versatility. Two procedures may be used to incorporate the Hader nylon clip into a denture base. The direct technique consists of attaching the clip to the denture base as a clinical procedure. With the indirect technique, the clip is attached during laboratory processing. An alternative method of attaching the clip with a metal superstructure is presented. This procedure combines the advantages of the direct and indirect techniques for incorporation of the nylon clip of the Hader bar into the denture base.     

Mandibular Hader bar attachment overdenture wearers: A five-year longitudinal clinical evaluation by electromyographic analysis

IntroductionElectromyography is used to evaluate the muscle activity of temporalis and masseter muscles in a comparative clinical research on effectiveness of masticatory cycle by conventional overdenture and use of overdenture with Hader bar attachment for five years established on a scientific level and is first of its kind.AimThe purpose of this study is to determine the response of co-ordination of stomatognathic system and the functional status of long-term overdenture use, which can be recorded in EMG.Material and MethodsTen patients were treated with maxillary conventional complete denture and mandibular overdenture. Electrical activity of masseter and temporal muscles were obtained in 3 groups. (Gp. I) After insertion of conventional overdenture with copings; (Gp. II) Overdenture with Hader bar attachment and (Gp.III) five years of use of overdenture with Hader bar attachment.Results and conclusionThe mean and standard deviation for all the patients showed an increase in muscular activity of temporalis and masseter muscles after long-term rehabilitation (x = 0.405; 0.407 and s = 0.0668; 0.1344 respectively, p = 0.0042 and 0.0074 which is <0.05). This study concludes that overdenture with Hader bar system, after five years of function provide a sound justification for a viable alternative treatment modality to provide overdenture with attachment service to patients.     

Implant Retained Auricular Prosthesis with a Modified Hader Bar: A Case Report

Auricular prostheses for defects of external ear are retained either by mechanical means or implants. All implant retained prostheses are retained by various means such as bar and clip, magnetic attachments or a combination of bar, clip and magnets. The commonest problem encountered with the bar and clip system is loosening of the clip after 3–4 months. When magnets are used as retaining component they tend to corrode over a period of time. So various alternative retention methods which possess good retentive qualities, ease of reparability and patient friendly were tried. In the present case a newly modified Hader bar design which can act as an additional retentive feature apart from the clip is employed to increase retention. The major advantages in the modified Hader bar system were that only two implants were employed, the additional loops in the Hader bar prevented micro movements and the retentive acrylic locks were easy to repair if broken. The modified Hader bar has anti-rotational slots which prevents the sliding or rotation of the prosthesis which gave new confidence to the patient who was otherwise worried of inadvertent displacement of the ear prosthesis while playing.     

Evaluation of stress patterns produced by implant-retained overdentures and implant-retained fixed partial denture

The purposes of this study were to photoelastically measure the biomechanical behavior of 4 implants retaining different cantilevered bar mandibular overdenture designs and to compare a fixed partial denture (FPD). A photoelastic model of a human edentulous mandible was fabricated, which contained 4 screw-type implants (3.75 × 10 mm) embedded in the parasymphyseal area. An FPD and 3 overdenture designs with the following attachments were evaluated: 3 plastic Hader clips, 1 Hader clip with 2 posterior resilient cap attachments, and 3 ball/O-ring attachments. Vertical occlusal forces of 100 N were applied between the central incisor and unilaterally to the right and left second premolars and second molars. Stresses that developed in the supporting structure were monitored photoelastically and recorded photographically. The results showed that the anterior loading, the overdenture with 3 plastic Hader clips, displayed the largest stress concentration at the medium implant. With premolar loading, the FPD and overdenture with 3 plastic Hader clips displayed the highest stresses to the ipsilateral terminal implant. With molar loading, the overdenture with 3 ball/O-ring attachments displayed the most uniform stress distribution in the posterior edentulous ridge, with less overloading in the terminal implant. It was concluded that vertical forces applied to the bar-clip overdenture and FPD created immediate stress patterns of greater magnitude and concentration on the ipsilateral implants, whereas the ball/O-ring attachments transferred minimal stress to the implants. The increased cantilever in the FPD caused the highest stresses to the terminal implant.     

The Change in Retentive Values of Locator Attachments and Hader Clips over Time

Purpose: The aim of this study was to examine early changes in retentive values of implant overdenture attachments during multiple pulls.
Materials and Methods: Two implant attachment systems (Hader bar and clip, Locator system) were used in this study. The experimental groups were divided into yellow Hader clips, white Locator attachments, and green Locator attachments. Each group consisted of 21 matrix attachments. The attachments were placed into a custom-made acrylic resin block seated passively on another acrylic block containing a Hader bar or two Locator abutments with different angulations. Each attachment was subjected to 20 consecutive pulls using a universal testing machine. The peak load-to-dislodgement of the attachments after each pull was documented, and the percent reduction of the peak load-to-dislodgement was calculated. One-way ANOVA and Tukey's honestly significant difference test were used for data analyses. A p ≤ 0.05 was considered significant.
Results: There was a significant difference in the percent reduction in peak load-to-dislodgement between the attachments after the first pull ( p = 0.005) and after the final pull ( p = 0.0001). The yellow Hader clips exhibited the least percent reduction in peak load-to-dislodgement (6.50 ± 3.59%) after the first pull, followed by the white Locator attachments (8.60 ± 4.42%); the green Locator attachments exhibited the greatest reduction (11.05 ± 4.94%).
Conclusion: The results of this in vitro study demonstrate that retentive values of the Locator attachments are reduced significantly after multiple pulls. Although this reduction might not be noticeable to the patient, it is recommended that the clinician place and remove the overdenture multiple times before delivery.     

Retention Characteristics of Attachment Systems for Implant Overdentures

PURPOSE: The aim of this study was to compare the retention characteristics of various overdenture attachment systems commonly used to retain overdentures to dental implants. MATERIALS AND METHODS: An edentulous mandibular model was constructed incorporating 2 parallel 4.0 mm x 13 mm Branemark implants placed in the canine regions. Attachments were embedded in a metal-reinforced experimental overdenture designed to be dislodged from the model by a universal testing machine. Tensile dislodging force was applied to the overdenture at a cross-head speed of 50 mm/min. Five overdentures were constructed for each of the attachment systems. The attachments evaluated were the Hader bar & metal clip, Locator LR pink, Locator LR white, Spheroflex ball, Shiner magnet, Maxi magnet, Magnedisc magnet, ERA white, and ERA gray. Each apparatus was tested with 5 specimens per attachment system. Peak load-to-dislodgement was measured. Analysis of variance and Scheffe multiple comparison tests were applied to the data with alpha< or = 0.05 level of significance. RESULTS: Peak load-to-dislodgement for all attachment systems ranged from 3.68 +/- 1.32 N to 35.24 +/- 1.99 N. Strain-at-dislodgement, calculated from stress-strain curves, ranged from 0.78 +/- 0.20% to 2.78 +/- 0.5%. The ERA gray attachment demonstrated the greatest retention, with a peak load-to-dislodgement of 35.24 +/- 1.99 N, and a relatively low strain-at-dislodgement of 1.64 +/- 0.09%. Less retention was recorded for the Locator LR white, Spheroflex ball, Hader bar & metal clip, and ERA white systems. The Locator LR pink attachment demonstrated still less retention with a load-to-dislodgement of 12.33 +/- 1.28 N. Significantly high strain-at-dislodgement was recorded for the Hader bar & metal clip and Locator nylon attachment systems. The lowest dislodging loads and strains were recorded for the Shiner magnet, Maxi magnet, and Magnedisc magnet attachments. CONCLUSIONS: Results suggest that the attachment systems evaluated may be grouped into high (ERA gray), medium (Locator LR white, Spheroflex ball, Hader bar & metal clip, ERA white), low (Locator LR pink), and very low (Shiner magnet, Maxi magnet, Magnedisc magnet) retention characteristics.     

Photoelastic analysis of the effect of palatal support on various implant-supported overdenture designs

STATEMENT OF PROBLEM: The effect of palatal support on various types of implant-supported maxillary overdenture designs has not been sufficiently assessed. PURPOSE: The purpose of this study was to photoelastically evaluate the palatal support of 3 designs of maxillary implant-supported overdentures. MATERIAL AND METHODS: A photoelastic model of an edentulous maxilla was fabricated with four 3.75 x 13-mm 3i implants. Three maxillary overdenture designs were fabricated: a splinted Hader bar incorporating 2 distal ERA attachments with anterior clips; non-splinted Zaag 4-mm direct abutments and attachments; and nonsplinted Locator 2-mm direct abutments and attachments. All restorative components and attachments were fitted and observed for passivity of fit and alignment. The overdentures were first tested with complete palatal coverage. Unilateral 25-lb loads were applied at the left and right first molars and the incisive papilla area. The photoelastic effects were monitored and recorded photographically. The palatal area was removed from the 3 overdentures and the loading regimens were repeated. RESULTS: The highest stresses under central loading were seen with the splinted Hader bar and complete palatal coverage, followed by similar levels of stress with either Zaag or Locator attachments. After removal of the palate, the center load demonstrated greater differences between designs. The highest stresses were observed with the Hader bar, followed by the Zaag and then Locator attachments. Lack of palatal coverage demonstrated higher levels of stress around implants and visible supporting tissues. The unilateral load produced the highest stress for the splinted Hader bar, followed by Locator, and then Zaag. CONCLUSIONS: Removal of the palatal support produced a greater effect and more concentrated stress difference for maxillary overdentures than differences between the attachment designs tested.     

An analysis of the implant‐supported overdenture in the edentulous mandible

This investigation examined the cumu‐lative survival rate of the implant‐supported overdenture using two types of attachments in patients treated at Show Chwan Memorial Hospital Implant Center from 1992 to 2006. Fifty‐one patients (30 men and 21 women) were treated with mandibular implant‐supported overdentures. Attachment systems used were the Hader bar with bilateral, cast ERA attachments (Group A, 31 patients with 15 men and 16 women, 134 implants) and the Hader bar with bilateral, distal extension cantilevers (Group B, 20 patients with 15 men and 5 women, 85 implants). Two hundred and four implants remained at the end of the follow‐up period. Among failed implants, 10 implants were in Group A (failure rate: 10/134 = 7·5%), whereas five implants were in Group B (failure rate: 5/85 = 5·9%). Sixty‐six point seven per cent (10/15) of failed implants were placed in the distal anterior mandible, and 33·3% (5/15) were placed in the middle anterior mandible. Survival was also examined with respect to condition of the opposing arch. Patients wearing a maxillary removable partial denture had the highest implant failure rate (5/51 = 9·8%), whereas the failure rate of the maxillary complete denture group was only 5·7%. The most frequent need for maintenance was wear over patrix component of ERA or Hader clip (n = 56). Eight patients experienced connector fracture between ERA and Hader bar, and one experienced distal extension cantilever fracture. The implant‐supported overdenture can be an effective and reliable alternative to the conventional complete mandibular denture. Fewer prosthetic complications were seen in overdentures retained with distal extension cantilever attachments.     

Retention and load transfer characteristics of implant-retained auricular prostheses

PURPOSE: The use of osseointegrated implants for maxillofacial prostheses reduces the need for adhesives, provides for a more stable and more esthetic prosthesis with thinner margins, and results in increased patient acceptance and confidence. The purpose of this study was to compare the retention and load transfer characteristics of differently designed implant-retained auricular prostheses. MATERIALS AND METHODS: A photoelastic model was fabricated of the auricular-temporal region of a human skull. Craniofacial implants 3.75 mm in diameter and 4 mm long were embedded in locations typically selected to retain auricular prostheses. Two retention mechanisms were evaluated on the implants: a Hader bar with 3 clips and the use of 3 Locator attachments. The retentive capacity of the prostheses was determined on an Instron test machine. Initial retention and changes with multiple removals were examined. Dislodgment forces were applied to each retentive device in the field of a circular polariscope. Resulting stresses were monitored and recorded photographically. RESULTS: The highest initial retention demonstrated by the Locator device was 12.4 +/- 0.9 lb, and the highest retention value for the Hader bar with clips was 7.5 +/- 1.1 lb. All attachments decreased in retention after multiple removals. The Locator devices produced higher peri-implant stresses compared to the Hader bar-with-clips design. CONCLUSIONS: Since higher retention is associated with higher stresses, results of this study suggest that a balance between retention and stress production is necessary in selecting a retention mechanism for the specific requirements of the patient being treated. The Locator attachment was correlated with higher retention values as well as with higher peri-implant stress compared to the Hader bar-and-clip attachment design. Retention decreased and then stabilized after multiple     

Does the retention system influence the stability of implant-supported maxillary overdentures? A comparison with fixed and conventional dentures

Purpose

The purpose of this in vitro study was to compare the stability of removable implant-supported maxillary overdentures with fixed complete dentures and conventional dentures.

Framework night guards for implant-retained auricular prostheses

Prosthetic ear rehabilitation with osseointegrated implants involves using a cast or preformed framework (bar) constructed to fit the implant abutments. Retention of the prosthesis is obtained through clips or magnets. Because the prosthetic ear is not worn during sleep, the ends of the retention bar are left exposed. These projections may become entangled with the linen or hair. To prevent this problem a night guard constructed of soft mouth-guard material is worn over the retentive bar while the patient is sleeping.     

Simplified procedure for replacement of retentive clips in a bar-retained implant overdenture

Replacing the retentive elements in a bar-retained overdenture can be a difficult and time-consuming procedure. This article describes an impression procedure that allows the matrices in a bar-retained implant overdenture to be replaced in the laboratory using a heat-cured rebase procedure. Long waxing screws are used, which allows the bar to be removed in the rebase impression and incorporated in a new master cast. After completion of the laboratory phase, the bar is screwed back onto the implant abutments and the denture, with new retentive matrices, is inserted.     

The influence of interimplant distance and attachment type on the retention characteristics of mandibular overdentures on 2 implants: 6-month fatigue retention values

This in vitro study evaluated the 6-month fatigue retention provided by 5 paired overdenture attachments placed at 3 different interimplant distances (19, 23, and 29 mm). Mean fatigue retention was calculated for each attachment type and compared with the retention produced by the other attachments tested and the initial retention values published earlier. Interimplant distance was found to play a significant role only in the retention of the Hader bar with red and yellow clips. A significant reduction in retention values was observed for 4 of 5 attachment types.     

Effect of mechanical and chemical cleaning on surface roughness of silicone soft relining material

PurposeThis study aims to investigate the effect of mechanical and chemical cleaning on the surface roughness of silicone soft relining materials.MethodsWe selected silicone soft relining materials with the highest (Soft) and lowest (Supersoft) Shore A hardness. In the abrasion test, specimens were cleaned 50,000 times using a kitchen sponge (Sponge), a soft (Soft brush) or hard (Hard brush) denture brush, or stored in water (No cleaning). In the immersion test, specimens were immersed in either water (Water), neutral peroxide denture cleanser (Neutral), alkaline peroxide denture cleanser (Alkaline), or hypochlorite denture cleanser (Hypochlorite) for 1440 h. Surface roughness of the arithmetic mean height of the surface (Sa) and maximum height (Sz) were measured before and after the tests. Data were analyzed using the Kruskal–Wallis and Mann–Whitney U tests.ResultsIn the abrasion test, significant differences were observed for Sa and Sz with Soft relining materials, but not for No cleaning and Sponge. In the immersion test, significant differences were observed for Sa and Sz with Soft relining materials, but not between Water and Neutral or Water and Alkaline. Significant differences were observed with Supersoft, except between Water and Neutral or Water and Alkaline for Sa and between Water and Neutral for Sz.ConclusionsMechanical cleaning using a sponge did not increase the surface roughness of the material with a high Shore A hardness. Furthermore, neutral peroxide denture cleanser did not increase the roughness of materials with high and low Shore A hardness.     

Effect of denture adhesives on oral moisture: A multicenter randomized controlled trial

PurposeThe purpose of this study was to investigate the effect of denture adhesives on oral moisture in a 10-center parallel randomized clinical trial.MethodsTwo hundred edentulous subjects wearing complete dentures were allocated into three groups: cream-type adhesive, powder-type adhesive and control groups. The adhesives (and saline solution in the control group) were applied to the mucosal surface of the dentures for 4 days, and baseline data and data after the intervention for eight meals over 4 days were obtained. For the main outcome, oral moisture was measured with a moisture checking device. Secondary outcomes were denture satisfaction, masticatory performance, denture retention, and occlusal force. In addition to between-group and within-group comparisons of oral moisture, investigations for secondary outcomes were undertaken in subgroups classified according to the degree of oral moisture at baseline (normal subgroup and dry mouth subgroup). Intention-to-treat analysis was also performed.ResultsBetween-group and within-group comparisons of oral moisture showed no significant differences. The cream-type and powder-type denture adhesives were significantly effective in the dry mouth group for denture satisfaction ratings of ability to masticate, stability, retention, and comfort of mandibular dentures (p < 0.05). The masticatory performance and retentive force of the dry mouth denture adhesive using groups were significantly improved after intervention (p < 0.05).ConclusionsThe oral moisture of complete denture wearers was not influenced by the use of denture adhesives. Our findings showed that denture adhesives improved subjective denture satisfaction, masticatory performance, and retention for complete denture patients with oral dryness.     

In vitro study of a mandibular implant overdenture retained with ball,magnet, or bar attachments: comparison of load transfer and denture stability

PURPOSE: When implants are used to support a removable overdenture, the optimal stress distribution to minimize both forces on the implants and denture movement is desirable. This study compared the stress patterns generated around implants and denture movement among three retention systems. MATERIALS AND METHODS: Two root-form implants were anchored in a mandibular model made of resin, and a removable overdenture on which all experiments were performed was fabricated. The surface of the model was covered with a layer of impression material to simulate oral mucosa. Ball/ O-ring, bar/clip, and magnetic attachments were used. A vertical force was applied to the left first molar and gradually increased from 0 to 50 N in 5-N steps. The resultant stress distribution and denture movement were evaluated. RESULTS: The ball/O-ring attachment transferred the least stress to both implants and produced less bending moment than the bar/clip attachment. Vertical force applied to the bar/clip attachment created immediate stress patterns of greater magnitude and concentration on both implants. CONCLUSION: This in vitro study suggested that the use of the ball/O-ring attachment could be advantageous for implant-supported overdentures with regard to optimizing stress and minimizing denture movement.     

Retentive force of stress-breaking attachments on maxillary implant overdentures

PurposeThe purpose of this study was to investigate the effect of the hardness of resilient materials applied to the female parts of specialized ball attachments, and the diameter of ball abutments on the retention of an implant overdenture.MethodsA cast chrome-cobalt framework was mounted onto a maxillary edentulous model. Eight different ball abutments, with diameters of 2.5, 2.75, 3.0 and 3.25 mm, and with undercut (UC) of 0.5 and 1.0 mm, which was the difference between the ball diameter and the neck diameter, were screwed into implants which were connected to resilient materials with four different degrees of hardness (58, 68, 78 and 90) conforming to ISO7619. A universal testing machine was used to test the 32 different attachments (crosshead speed 3 mm/min). Three tests of 10 consecutive pull separations were done in both vertical and oblique directions. After 10 consecutive pull separations, the inner surfaces of the resilient materials were examined by a scanning electron microscope (SEM). The measured retentive forces were analyzed statistically using ANOVA and Tukey's tests.ResultsBoth the hardness of the resilient materials and the diameter of the ball abutments significantly affected the retentive force (P < 0.05).ConclusionsThe designs with the diameter of the ball abutments ranging from 2.75 to 3.0 mm and UC of 0.5 mm, and with the hardness of the resilient materials ranging from 68 to 78, were considered to be suitable for this attachment system.