|Year : 2020 | Volume
| Issue : 2 | Page : 84-92
A comparative study to evaluate the retention of conventional retention sleeve material versus retention.sil 600 in implant-retained overdentures: In vitro study
Shuja Mohammed Khan, Gaurav Issar, Siddharth Bansal, HG Jagadeesh, Shweta Tyagi
Department of Prosthodontics and Crown and Bridge, ITS-CDSR, Muradnagar, Uttar Pradesh, India
|Date of Submission||18-Jun-2020|
|Date of Acceptance||12-Oct-2020|
|Date of Web Publication||18-Dec-2020|
Dr. Shuja Mohammed Khan
Post Graduate Trainee, Department of Prosthodontics Including Crown & Bridge, Maxillofacial Prosthodontics & Oral Implantology, I.T.S Centre for Dental Studies and Research, Muradnagar, Ghaziabad-201 206, Uttar Pradesh
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Purpose: The aim of this study was to assess and evaluate the retention of conventional retentive sleeve material versus retention.sil in implant-retained overdentures.
Methodology: Custom-designed models of uniform dimensions were made from heat-polymerized polymethyl methacrylate resin. The model had two components which comprised a lower member (matrix) and an upper member (patrix). The lower member (matrix) was embedded with two ADIN implant analogs attachment (Adin Implant System Ltd. Israel) of 3.75 mm × 10 mm with prefabricated ball attachment at an interimplant distance of 20 mm. The upper member was prepared to receive two different retention sleeve materials, conventional retentive/plastic sleeve attachment (Adin Implant System Ltd. Israel), and retention.sil 600 (Bredent medical GmbH and Co. KG). Using a universal testing machine, each of the models was subjected to 100 pulls each to dislodge the upper member from the lower member, and the force values as indicated on the digital indicator were tabulated.
Statistical Analysis Used: Statistical analysis comprised Kolmogorov–Smirnov test, Friedman test, Mann–Whitney test, and Wilcoxon signed-rank test.
Results: The statistical model revealed that when subjected to vertically directed forces, the conventional retentive/plastic sleeve attachment (Adin Implant System Ltd. Israel) developed higher retentive force as compared to the retention.sil 600 (Bredent medical GmbH and Co. KG).
Conclusions: The conventional retentive sleeve material maintains their retentive capacity longer than the retention.sil 600. Further research is required to increase the retentive force in retention.sil material, thereby increasing denture retention and stability.
Keywords: Overdenture attachment, retention.sil 600, retentive force
|How to cite this article:|
Khan SM, Issar G, Bansal S, Jagadeesh H G, Tyagi S. A comparative study to evaluate the retention of conventional retention sleeve material versus retention.sil 600 in implant-retained overdentures: In vitro study. J Dent Implant 2020;10:84-92
|How to cite this URL:|
Khan SM, Issar G, Bansal S, Jagadeesh H G, Tyagi S. A comparative study to evaluate the retention of conventional retention sleeve material versus retention.sil 600 in implant-retained overdentures: In vitro study. J Dent Implant [serial online] 2020 [cited 2021 Apr 13];10:84-92. Available from: https://www.jdionline.org/text.asp?2020/10/2/84/303916
| Introduction|| |
The most common problem associated with the management of edentulous patients is the severely resorbed residual alveolar ridge of the lower jaw, especially in older age when adaptive capacities are reduced.,,,, This compromised situation consequently results in the fabrication of unsatisfactory dentures with poor retention and stability, reduced oral function, and may further precipitate psychosocial problems.,,,
However, the stabilization of the lower denture with two interforaminal implants has provided reliable and predictable treatment outcomes. It is regarded as the minimum standard of care for edentulous patients. Retention and stress distribution are the two important factors for the prognosis of the prosthesis. Retention is the function of and is directly related to the attachment system employed. The success of implant-retained overdentures primarily depends on the retentive capacity of its attachment element to sustain its long-term functionality. An attachment-retained dental prosthesis can improve patient esthetics and facilitate function.
The choice of the attachment is dependent upon the retention required, jaw morphology, anatomy, mucosal ridge, oral function, and patient compliance for recall. Ball attachments and bar units for implant overdentures have evolved from the early 1960s. Ball attachments were considered the simplest type of attachments for clinical application with tooth- or implant-supported overdentures. However, it is also well documented that o-rings/sleeves gradually loose retention and must be replaced periodically. On the other hand, increased technique sensitivity and costs but with favorable stability have been reported regarding the bar attachments.
Other disadvantages of the bar system include mucosal hyperplasia, hygiene problems, and the necessity of the retention clip's activation.,, Typically, the combination of materials in the overdenture attachments comprises of a metal–metal or metal–plastic/nylon contact which might show differences regarding surface wear and thus resistance to repetitive removal and insertion cycles., In addition to this, a change in the retentive capacity of the attachment systems is expected when the overdenture is subjected to a period of service in the oral cavity under the influence of inherently present fluids and ingested food and liquids during mastication and insertion and removal of the prosthesis. Micro- and macromovements between the retentive surfaces of an attachment during mastication and removal of the overdenture will lead to wear and diminish retentive forces over time.
Retention.sil (Bredent medical GmbH and Co. KG) is a silicone with very high tensile strength, which is perfectly suited to ensure a resilient position of the denture. On the other hand, TiSi.snap is an abutment system with defined retention and a good guidance of the denture. This combination provides the high level of patient comfort while eating and chewing and avoids changes to the position of the denture. Furthermore, it is more economical than the conventional female component/metal housing.
The adhesion of the denture on the TiSi.snap abutment is adjusted by selecting one of the three retention levels of retention.sil-soft-medium-hard. Retention.sil surrounds the TiSi.snap abutment completely and offers high chewing comfort to a resilient bite based on the cushioning effect of retention.sil silicone.
The use of metal housing/female component can be avoided using retention.sil, which further reduces the risk of the postinsertion complications. Moreover, as o-rings/sleeves gradually loose retention, thus it was decided to conduct a study to assess and evaluate the retention of retention.sil over conventional retentive sleeve material.
Aim of the study
The aim of this study was to assess and evaluate the retention of conventional retentive sleeve material versus retention.sil in implant-retained overdentures.
- To evaluate the retention of conventional retentive sleeve material in implant-retained overdentures after repeated insertion-removal cycles
- To evaluate the retention of retention.sil in implant-retained overdentures after repeated insertion-removal cycles
- To compare and evaluate the retention of conventional retentive sleeve material versus retention.sil in implant-retained overdentures after repeated insertion-removal cycles.
Materials and equipments
- Custom-designed models of uniform dimensions made with heat-polymerized polymethyl methacrylate resin (DPI Heat Cure, DPI, Mumbai, Maharashtra, India) [Figure 1]a
- Two implant analogs (Adin Implant System Ltd. Israel) – 3.75 mm diameter, 10 mm length [Figure 1]b
- Prefabricated ball/plastic sleeve attachment (soft) (Adin Implant System Ltd. Israel) [Figure 2]
- Retention.sil 600 (Bredent medical GmbH and Co. KG) [Figure 3]
- Resin cement (Relyx™, 3M ESPE)
- Universal testing machine (UTM) – Asian Test Equipments [Figure 4]
- Customized jig and metallic clips.
|Figure 1: (a) Custom-designed model. (b) Implant analog 3.75 mm × 10 mm (Adin Implant System Ltd. Israel)|
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|Figure 2: Prefabricated ball/plastic sleeve (soft) attachment with metal housing (Adin Implant System Ltd. Israel)|
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|Figure 3: Retention.sil 600 with Multisil-Primer (Bredent medical GmbH and Co.KG)|
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| Methodology|| |
Fabrication of study models
- An experimental setup simulating a clinical implant-retained overdenture situation supported by two implants was devised
- Custom-designed models of uniform dimensions (lower member 65 * 16*20 mm and upper member 65 * 16*10 mm) were made from heat-polymerized polymethyl methacrylate resin (DPI Heat Cure, DPI, Mumbai, Maharashtra, India) [Figure 1]a
- The model had two components which comprised a lower member (matrix) and an upper member (patrix). The lower member (matrix) was embedded with two ADIN implant analogs attachment (Adin Implant System Ltd. Israel) of 3.75 mm × 10 mm with an interimplant distance of 20 mm [Figure 5]a
- One lower member (overdenture) model was prepared and five upper member (denture) samples were prepared for each group.
- Group A ball/plastic sleeve attachment (soft)
- Group B ball/retention.sil 600 attachment
The implant analogs (ADIN 3.75 mm × 10 mm) were placed in the acrylic models using physiodispenser, simulating the conventional placement of the implant in osteotomy site in the mandible and subsequently secured with resin cement (Relyx™, 3M ESPE, USA).
|Figure 5: (a) Implant analogs placed on the lower member. (b) Prefabricated ball attachment placed on implant analogs. (c) Gingival mask applied to simulate gingiva|
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Implant overdenture attachment systems
- The prefabricated ball attachment system was secured into the implant replicas on the acrylic resin model and was tightened to 35 Ncm [Figure 5]b. A gingival mask was applied to simulate gingiva [Figure 5]c.
Group 1: prefabricated ball/plastic sleeve attachment (Adin Implant System Ltd. Israel).
- At the marked points, the intaglio surface of the upper member was ground out.
- The plastic sleeve was placed in the metal housing and was picked up using autopolymerizing clear acrylic [Figure 6]a.
- After polymerization, the upper member was removed and the excess acrylic was removed with the acrylic trimming burs [Figure 6]b.
|Figure 6: (a) Metal housing placed on ball attachment for pickup. (b) Final picked up upper member model for Group A|
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Group 2: Retention.sil 600 (Bredent medical GmbH and Co. KG)
- At the marked points, the intaglio surface of the upper member was ground out
- After the cavity was conditioned with the Multisil-Primer, the retention.sil is filled up to the top [Figure 7]a and [Figure 7]b.
- The upper member was inserted with the still soft retention.sil on ball attachments on the lower member
- After 3 min, the upper member was removed and the excess retention.sil was removed with the silicone cutters [Figure 7]c.
|Figure 7: (a) Application of Multisil-primer. (b) Application of retention.sil 600 material. (c) Final picked up upper member for Group B|
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- Acrylic overdentures (upper member) with respective attachment systems were placed on the acrylic edentulous mandibular models (lower member)
- Customized jigs were attached to the upper and lower members, respectively and were secured using clamps in the UTM machine
- With the UTM (Asian Test Equipments), each of the models was subjected to 100 pulls each to dislodge the upper member from the lower member, and the force values as indicated on the digital indicator were tabulated [Figure 4].
- The dislodging force was applied in a vertical direction in the center of the acrylic block with the UTM operating at a crosshead speed of 2 mm/30 ms. The readings were taken from the start of the test.
| Results|| |
The mean values and standard deviation are shown in [Table 1]. The mean force for conventional retention sleeve material after 1st, 50th, and after 100th dislodgement pull was 20.24 ± 1.5 N, 21.57 ± 3.5 N, and 16.63 ± 2.8 N, respectively.
The Kolmogorov–Smirnov tests for normality revealed no normal distribution (P < 0.05) for both Groups A and B; thus, normal distribution was not assumed.
A comparison of the repeated measures was performed for Group A and Group B using Friedman's test. The results show a statistically significant decrease in concentration [Table 2],[Table 3],[Table 4],[Table 5].
Since the Friedman test was significant, Pairwise significance using Wilcoxon's signed rank test for each group was applied.
In Group A, a statistically significant relationship was seen between 1st 100th pull and 50th 100th dislodgement pull with P < 0.043. However, there was no statistically significant correlation between 1st 50th dislodgment pull with P < 0.225. [Table 6],[Table 7].
In Group B, a statistically significant relationship was seen between 1st 50th, 1st 100th pull, and 50th 100th dislodgement pull with P < 0.042, P < 0.043, and P < 0.043, respectively.[Table 8],[Table 9].
IIn the present study, a comparison between both the groups for each of the dislodgment pull using the Mann– Whitney test was applied. The test showed a statistically significant relationship between Group A and Group B. [Table 10],[Table 11].
| Discussion|| |
The underlying principle in employing retentive implant overdenture systems for the treatment of edentulous patients is to increase denture retention and stability, thereby promoting chewing function as well as patient comfort and compliance., One of the main problems with implant overdentures is the potential complication associated with the attachment mechanisms. Stud type, ball, and conventional bar attachments are the commonly used anchorage systems in implant-supported overdentures and their efficacy is scientifically supported.,,, In comparison with bar attachments, ball anchors were preferred by clinicians because they were less technique sensitive, cost-effective, easy to use, and to repair. The unsplinted systems are indicated in clinical situations with diminished interarch distances and are further advantageous in terms of hygiene, ease of fabrication, and initial treatment cost, whereas bars present the lowest rate of prosthetic complications.
This study was performed under a controlled experimental simulation to evaluate the retention of conventional retentive sleeve material versus retention.sil 600 in implant-retained overdentures.
The experimental setup, however, may have had a few limitations. The sample size of the specimen used was relatively small, but was in accordance with previous similar experiments., It has to be kept in mind that for the current in vitro experiment, only monodirectional forces were applied, which does not represent a realistic model for a clinical situation with overdentures. There, the main forces are generated in the region of the first molars which will lead to rotational forces on the attachments through leverage.
Furthermore, also horizontal forces will act on any overdenture attachment in a clinical situation, but these forces are very difficult to simulate in an in vitro model.
SEM analyses of the attachment components were not performed, as the scope of this study was limited to evaluating the changes in the retentive forces and removal torque. Further, fractures or material failures due to fatigue were not encountered in this study; hence, the need for a SEM evaluation was deemed unnecessary.
During the course of the study, the different retentive material showed a complex evolution with peaks as well as increasing and/or decreasing mean retentive forces. The statistical model revealed a significantly different behavior of the conventional retentive sleeve material and retention.sil.
The plastic ball cap pink soft (Adin Implant System Ltd. Israel) made up of nylon was used as conventional retentive sleeve material. The retention.sil provided by the manufacturer comes under as soft, medium, and hard depending on the hardness. Retention.sil 600 was selected for the study with a shore hardness of 65SH and pull-off force of 600 g/6N. Thus, plastic ball cap pink soft (Adin Implant System Ltd. Israel) and retention.sil 600 (Bredent medical GmbH and Co. KG) were selected as these materials' retentive force values were the nearest.
When compared to retention.sil 600, the conventional retentive sleeve material exhibited the highest peak as well as the highest mean retention force at the end of the study. Furthermore, the conventional retentive sleeve material showed significantly more decrease in retentive potential in comparison to retention.sil 600 [Figure 8]. This attributes to component wear and plastic deformation of the nylon inserts which warrants the periodic change of the retentive sleeve/o-rings as the retentive force decreases. As the rate of loss of retention in retention.sil 600 is less, it does not require early replacement of retentive material as compared to conventional material.
|Figure 8: Progression of mean retentive forces of the two retentive materials|
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Although the manufacturer has provided the retentive.sil 600 with less retentive force, this material is good for patients with poor manual dexterity who have difficulty in inserting and removing the overdenture. Retentive.sil 600 does not require metal housing/female component and material is placed directly into space made on the intaglio surface of the denture. It is a convenient economical alternative for replacing old worn-out retentive sleeve overdenture cases. Therefore, retention.sil 600 proves to be less technique sensitive, cost-effective, and easy to use material.
Therefore, under specific circumstances, matching the retentive characteristics of the attachment system to the physical conditions and needs of the patient may be an important treatment planning consideration and critical to restorative success. Further research is required to increase the retentive force in retention.sil material, thereby increasing denture retention and stability.
| Conclusions|| |
Conventional retentive sleeve material exhibited the highest peak as well as the highest mean retention force compared to retention.sil 600.
Although retention.sil has less retentive force in comparison to conventional retentive sleeve material, it can be a choice of material in patients with poor manual dexterity.
Further research is needed to better understand the mechanisms of silicone as retentive material in implant-supported overdentures.
Further research is required to increase the retentive force in retention.sil material, thereby increasing denture retention and stability.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8]
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6], [Table 7], [Table 8], [Table 9], [Table 10], [Table 11]