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 Table of Contents  
Year : 2022  |  Volume : 22  |  Issue : 3  |  Page : 268-271

Retention force of Molloplast-B with ball attachment in implant-supported overdentures: An in vitro study

1 Department of Removable Prosthodontics, Faculty of Dentistry, Damascus University, Damascus, Syrian Arab Republic
2 Department of Oral and Maxillofacial Surgery, Faculty of Dentistry, Damascus University, Damascus, Syrian Arab Republic

Date of Submission25-Jan-2022
Date of Decision18-Apr-2022
Date of Acceptance29-May-2022
Date of Web Publication18-Jul-2022

Correspondence Address:
Joul Kassis
Department of Oral and Maxillofacial Surgery, Faculty of Dentistry, Damascus University, Damascus
Syrian Arab Republic
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/jips.jips_43_22

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Aim: The purpose of this study is to evaluate the retention effectiveness of Molloplast B as a female attachment compared to O rings' in implant supported overdentures.
Settings and Design: This systematic review and meta-analysis was evaluated using the Preferred Reporting Items for Systematic Review and Meta-Analysis guidelines.
Materials and Methods: Sixteen female part models were divided into two groups: eight female parts made with O ring (Group A) and eight female parts made with Molloplast B (Group B). All of the models were soaked in artificial saliva for 24 h, then, their retention force was measured in Newton using a Universal mechanical testing machine, initially, after 500, after 1000, and after 1500 of loading and dislodging cycles.
Statistical Analysis Used: The statistical analysis was conducted by using one way ANOVA test and Bonferroni test. SPSS Software (SPSS, Version 27, IBM Co., Chicago, IL, USA).
Results: After 1500 loading and dislodging cycles, Group B has the highest mean retention force (4.09), followed by Group A, which has a mean retention force of 3.73.
Conclusion: Molloplast B with a 2.7 mm diameter ball attachment lost the least amount of retention force after 1500 loading and dislodging cycles.

Keywords: Attachment, implant, Molloplast-B, O-ring, overdenture, retention

How to cite this article:
Salloum A, Alassafeen A, Kassis J. Retention force of Molloplast-B with ball attachment in implant-supported overdentures: An in vitro study. J Indian Prosthodont Soc 2022;22:268-71

How to cite this URL:
Salloum A, Alassafeen A, Kassis J. Retention force of Molloplast-B with ball attachment in implant-supported overdentures: An in vitro study. J Indian Prosthodont Soc [serial online] 2022 [cited 2022 Dec 7];22:268-71. Available from: https://www.j-ips.org/text.asp?2022/22/3/268/351282

  Introduction Top

Edentulism is a common problem that develops as individuals get older and it has serious consequences for their general health.[1] Complete dentures are one of the most common treatment options for edentulous patients because they are simple and affordable.[2] In edentulous patients, resorption of the alveolar ridge, particularly in the mandible, results in a loss of retention, stability, and patient's comfort.[3] Implant-supported overdentures have a number of advantages over regular dentures, including increased retention and stability, improved mastication efficiency, and improved quality of life.[4],[5] Implant-supported overdentures use a variety of attachment devices, including ball, bar, magnet, telescopic, and locators.[6] A ball attachment is a stud attachment that consists of a ball abutment that is attached to the implant and a female portion that is a silicone loop inside a metal cap housing.[7],[8] Ball attachments improve force transfer to the implant's body and improve overdenture stability.[9] The ball attachment requires about 12 mm of occlusal space, which affects esthetics when there is not enough; in addition, the metal cap housing of the ball attachment is a weak point of the overdenture and may cause repeated fractures; and subsequently, the attachment will lose much of its retention after 6–12 months of use.[10] Soft liners are used with dentures to distribute functional forces on the denture bearing area due to their viscoelastic properties. They are classified as permanent or semi-permanent and are further divided into silicone elastomers and plasticized acrylics, both of which can be heat cured or self cured.[11] Molloplast-B (DETAX, Germany) is a permanent heat-cured silicone soft liner with a long-lasting viscoelastic property.[12] In a Shernoff technical report in 1984, it was used as a female part with grooves on surviving roots and a conventional overdenture to promote retention.[13] Another technical remark found that employing heat-curing soft liner materials as a female connector with implant-supported overdentures produced good outcomes for 1–6 years.[14] Silicone soft liners (including Molloplast-B) outperformed acrylic soft liners in a research of retention force of numerous soft lining materials when used as a female connector with bar connector.[15] Ball abutment retention force was acceptable with different types of self-curing acrylic and silicone soft liners when employing a ball with a diameter of 2.5 mm or greater.[16],[17] The retention force of Molloplast-B with ball abutment had never been studied before.

The purpose of this study is to determine the retention force of Molloplast-B as a female connector with ball abutment as a male connector after a series of loading and dislodging cycles as a cost-effective method that requires less vertical occlusal space than metal cap housing after a number of loading and dislodging cycles.

  Materials and Methods Top

Using models, in which one male connector (ball abutment with a diameter of 2.7 mm) and sixteen female connectors divided into two groups:

  1. Group A: Eight Molloplast-B attachments
  2. Group B (A control group): Eight O-ring attachments.

A male connector was inserted into a stone model [Figure 1], after which a spacer (6 mm in diameter and 5 mm in height) was made from flexible temporary light-curing material (ReLight tempo, TehnoDent company, Russia), which was injected around the male connector inside the wax cylinder and light-cured for 20 s, and after that, the wax cylinder was removed, leaving a space for Molloplast-B to be inserted into the acrylic base during the processing procedure. The lost wax technique was used to create a wax model that resembled an experimental base before being turned into heat-cured acrylic. The wax model, a stone model with the male connector, and a flexible temporary light-curing spacer were all placed within the processing flask. After melting the wax and isolating both parts of the flask, a heat-curing acrylic (Vertex Regular, Vertex Dental B. V., the Netherlands) was used to fill the melted wax gap, simulating the experimental basis. After removing the flexible temporary light-curing material, the flask was pressurized with hydraulic pressure for 15 min before being opened to place Molloplast-B. The entire processing method was carried out in accordance with the manufacturer's instructions.
Figure 1: (A) Male connector, (B) O-ring female connector, (C) Molloplast-B connector

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The O-Ring attachment was connected to the experimental base in the same way as the flexible temporary light-curing material, but instead of using flexible temporary light-curing material, the O-Ring attachment was connected directly to the male connector [Figure 2], and the heat curing acrylic processing procedure was used to measure the retention force. The experimental bases and stone model were soaked in artificial saliva for 24 h then the stone model was fixed to the experimental base, and the initial retention force was measured with a universal testing machine (Testometric Co, UK). Retention force was measured at the beginning, after 500, after 1000, and after 1500 loading and dislodging cycles.
Figure 2: O-ring connector in place after processing the experimental base (Male connector)

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Statistical analysis

The retention forces were calculated using score values and the results were analyzed using one way ANOVA test and Bonferroni test. SPSS Software (SPSS, Version 27, IBM Co., Chicago, IL, USA) was used to perform the statistical analyses of the data. Numerical variables were described with a mean (± standard deviation). A statistical significance level of P < 0.05 was used.

  Results Top

Molloplast-B attachment had a retention force of (4.64 ± 0.2 N) initially. After 500 cycles, the testing machine reported (4.6 ± 0.2 N), then (4.38 ± 0.2 N) after 1000 cycles, and finally (4.09 ± 0.3 N) after 1500 cycles. In terms of O-Ring attachment, the retention force was initially (4.94 ± 0.3 N), then (4.86 ± 0.3 N) after 500 cycles, then (4.43 ± 0.3 N) after 1000 cycles, and finally (3.73 ± 0.2 N) after 1500 cycles [Table 1].
Table 1: Comparison of maximum retention force in different stages

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According to the one-way ANOVA test, there were significant differences between Molloplast-B attachment and O-Ring attachment regarding retention force in stages (initially, after 500 cycles, after 1000 cycles, and after 1500 cycles) (P < 0.001), which means that at the 95% confidence level, there is statistical significance in the mean retention forces between both groups according to the studied stages, [Table 2] however, when results were analyzed employing Bonferroni test for multiple comparisons, the test showed no statistically significant differences between both groups at the stage (after 1000 cycles) [Table 3].
Table 2: The results of the one-way ANOVA test to study the significance of differences in the average retention force, in Newton's, among the two groups of the retention method studied in the research sample, according to the stage studied

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Table 3: The results of binary comparison using the Bonferroni test to study the significance of the binary differences in the average retention force (in Newton's) among the two groups (A and B)

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  Discussion Top

Ball attachment is one of the most popular attachment techniques for implant-supported overdentures, and the majority of ball attachments rely on the O-Ring connector for optimal retention.[18] Although the O-Ring is a good attachment system, it has several flaws, such as diminishing its holding force with time (6–12 months).[19] While O-Ring attachments rely on the silicon ring's viscoelastic properties to obtain retention with ball attachment,[20] Molloplast-B, which has viscoelastic features as well, can also be used with ball attachment, especially because Molloplast-B keeps its viscoelastic capabilities for a long time.[21]

The testing sample consisted of sixteen female connectors separated into two groups: (Group A) eight Molloplast-B attachments, (Group B) as a control group, with another eight O-ring attachments, and one male connector (A ball attachment) with a diameter of 2.7 mm. All of the connectors were submerged in artificial saliva for 24 h, and the maximum retention force was recorded in four phases using a universal testing machine (initially, after 500 cycles, after 1000 cycles, and after 1500 cycles). There were no significant variations in Molloplast-B attachment retention force after 500 cycles, which can be explained by Molloplast-B long-lasting's viscoelastic properties and high wear resistance after a significant number of dislodging cycles.[15] After 1000 cycles, however, there was no significant difference between Molloplast-B and O-Ring attachments, indicating that Molloplast-B and O-Ring attachments are both durable over time.[22] After 1500 cycles, however, a significant difference was observed between Molloplast-B and O-Ring attachments, owing to the former's higher wear resistance after dislodging cycles.[23] compared to the latter's loss of retention with additional dislodging cycles.[19] As a result of its wear resistance, long-lasting viscoelastic properties, cost-effectiveness, and esthetic properties in cases of lack of vertical space for overdenture, Molloplast-B could be a good female connector with ball attachment in implant-supported overdentures, in addition to having an easy way to gain retention in implant-supported overdentures without interrupting teeth arrangement.

  Conclusion Top

Under the experimental conditions of this study:

  1. Regardless of whether the female connection is Molloplast-B or O-Ring, there is a continuous loss of retention with ball attachments throughout dislodging cycles under the experimental conditions of this research
  2. During dislodging cycles, retention loss with the Molloplast-B female connector is lower than with the O-Ring female connector
  3. When used with a 2.7-mm diameter ball attachment, the Molloplast-B female connector may survive for a longer time.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

  References Top

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  [Figure 1], [Figure 2]

  [Table 1], [Table 2], [Table 3]


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