|Year : 2019 | Volume
| Issue : 4 | Page : 183-188
Effect of denture cleansers with and without fatigue stress on retention of locator attachments: in-vitro study
Mohammed A. Hamza Dentist , Fadel E. Elbhotty, Mohamed M. El-Sheikh
Department of Prosthodontics, Faculty of Dentistry, Tanta University, Tanta, Egypt
|Date of Submission||26-Jan-2019|
|Date of Acceptance||18-Jun-2019|
|Date of Web Publication||28-Feb-2020|
Mohammed A. Hamza
Dentist, Department of Prosthodontics, Faculty of Dentistry, Tanta University, Tanta
Source of Support: None, Conflict of Interest: None
To evaluate the effect of denture cleansers with and without fatigue stress on the retention of the locator attachments.
Materials and methods
Three dummy implants of length (13 mm) and a diameter of 4.2 mm with their locator abutments were embedded into three acrylic resin blocks. Seventy pink locator attachments were divided into three groups: 10 for group I, 30 for each group II and group III. Group I exposed to 600 cycles of insertion and removal equivalent to 6 months use, group II and group III was subdivided into three subgroups, A, B, C according to the type of cleaner which was soaked in water, chlorhexidine gluconate 2% and alkaline peroxide solution for a period equivalent to 6 months. Group III was soaked in water, chlorhexidine gluconate 2% and alkaline peroxide solution, then exposed to 600 cycles of insertion and removal. The pink locator was tested for load to dislodgment on universal testing machine with a load cell of 5 kN at a crosshead speed of two in/min. Retention of locator attachments were statistically analyzed using Mann–Whitney test. Difference of mean values between more than two groups was tested by Friedman χ2-test.
Group I: The retention of pink locator attachments was significantly decreased after 600 cycles of insertion and removal P = 0.005. Group II: The retentive value for attachment soaked in chlorhexidine gluconate 2% and that soaked in alkaline peroxide solution was significantly lower than that soaked in water (P = 0.001). Group III: the locator soaked in water and chlorhexidine gluconate 2% and alkaline peroxide solution was significantly affected after 600 cycles of insertion and removal.
Chlorhexidine gluconate 2% and alkaline peroxide solution has significant decrease the retention of pink locator attachment. Fatigue has significant effect on the retention of locator attachment either with or without the use of denture cleansers.
Keywords: denture cleansers, fatigue, locator attachment, overdenture
|How to cite this article:|
Hamza MA, Elbhotty FE, El-Sheikh MM. Effect of denture cleansers with and without fatigue stress on retention of locator attachments: in-vitro study. Tanta Dent J 2019;16:183-8
|How to cite this URL:|
Hamza MA, Elbhotty FE, El-Sheikh MM. Effect of denture cleansers with and without fatigue stress on retention of locator attachments: in-vitro study. Tanta Dent J [serial online] 2019 [cited 2020 Mar 28];16:183-8. Available from: http://www.tmj.eg.net/text.asp?2019/16/4/183/279732
| Introduction|| |
For more than 100 years, complete denture was the only treatment option available for completely edentulous patients. Complete dentures rely on the form of the remaining bony ridge for retention and support, but even when the dentures are judged to be satisfactory, many edentulous patients cannot eat certain foods or even speak clearly because of lack of denture retention.
With the introduction of dental implants, dentistry entered a new era, in which the previous problems of retention and stability of conventional dental replacements, especially, the mandibular one, could be resolved. According to the McGill Consensus statement, the conventional denture is no longer the best available treatment for an edentulous resorbed mandible. The evidence available today suggests that two implant-supported overdenture should be considered the first choice of treatment for such patients.
Overdentures can be classified according to support into entirely implant-supported overdentures and implant-mucosa-supported overdentures. The load sharing is obtained by allowing the prosthesis movement under functional loads. The movement is allowed by the resiliency of the attachment used as in stud attachments, by a spacer layer between the superstructure and the attachment as in bars or resilient telescopic attachment. The maximum bite force of subjects with a mandibular denture supported by implants is 60–200% higher than that of subjects with a conventional denture.
The attachment mechanism in the implant overdenture provides enhanced retention and stability compared to the conventional denture. The support is gained from both the intraoral tissues and dental implants. The Attachments can be classified into: Frictional, mechanical, frictional and mechanical and magnetic attachments. The retentive force of the locator attachment is gained through mechanical interlocking; that of ball attachment is frictional contact and magnetic attachments is magnetic forces of attraction between the patrices and matrices.
The locator attachment system is an attachment system with self-aligning feature and has dual retention inner and outer. Locator attachments come in different colors white, pink and blue and each has different retentive value. Additional features are the extended range attachments, which can be used to correct implant angulation up to 20° they are offered in green, which has standard retention, and red, which has extra-light retention. The reduced height of this attachment is an advantageous for cases with limited interocclusal space or when retrofitting an existing old denture.
It has been suggested that the minimum retentive force expected for a single individual unsplinted attachment might be 4 N although various retentive forces ranging from 1 to 85 N have been reported for different attachment systems in which the mandibular overdentures are retained by multiple implants. Denture cleanliness is essential to prevent malodour, poor esthetics, and the accumulation of plaque/calculus and biofilm.
A survey by Jagger and Harrison found that a large number of people did not know how to clean their dentures satisfactorily, either as a result of never having been given advice or not following that advice. Denture stomatitis, also known as atrophic candidiasis, is the most common fungal infection in elder patients and in those who wear dentures. Dentures can be cleaned mechanically, chemically, or through a combination of these [7–10].
Ideally, denture care products should be:
- Easy of handling.
- Effective for removal of inorganic/organic deposits and stains.
- Bactericidal and fungicidal.
- Nontoxic to the patient.
- Remove odour.
- Nondeleterious to the denture materials and inexpensive.
Alkaline peroxides are the most used denture cleansers. Alkaline peroxides, when dissolved in water, become alkaline hydrogen peroxide solutions. The degradation of peroxide liberates oxygen bubbles that mechanically clean dentures when in contact with debris. Such peroxides are recommended for the removal of mucin present in saliva and food remains and can also prevent the formation of stains and calculus. They can be used as antimicrobial agents as well. However, they present the adverse effect of bleaching plastic materials,.
| Materials and Methods|| |
Three locator matrix and 70 pink locator Patrix were used in this study. One matrix was used for each group. Seventy pink locator plastic cap (Patrix) were divided into three groups, group I (n = 10), group II (n = 30) and group III (n = 30) according to the experimental design [Table 1].
Three denture cleanser solutions were used in this study.
- Tap water was used as a control.
- Chlorhexidine gluconate 2% (Healthpoint, London, UK).
- Alkaline peroxide solution (Corega tabs).
Fabrication of block A
Three blocks A were prepared and fabricated from self-cure acrylic resin (Acrostone Co., Cairo, Egypt) that mixed according to the manufacture's recommendation and poured in specific mold of Teflon (Dupont, Wilmington, Delaware, USA) with internal diameter 22 mm diameter × 28 mm length. The mold was lathed in lathe machine (C 10 MB, Sofia, Bulgaria). A cover for the mold from Teflon also was fabricated with central projection to identify the center of the acrylic block. The Teflon cylinder painted with petroleum jelly (Vaseline; Unilever Company, London, UK) to avoid adhesion of the self-cure acrylic resin to the walls of the cylinder [Figure 1].
Dummy implant fixation
After finishing and polishing of block A, around hole was made at the center of the block with the aid of dental surveyor (Degussa VGI, Germany) with straight hand piece. The proposed site firstly marked by using round bur. Pilot drill was used to prepare the initial site to expand the width slightly, then twist drill moved to enlarge the prepared pilot channel to diameter smaller than diameter of the dummy implant. The implant length was initially determined by graduated marking on the twist drill.
Luting resin cements (self-adhesive resin cement, translucent; GC Corporation, Tokyo, Japan) was applied in the prepared site in the resin block before dummy implant placement. Dummy implant (Implant Direct LLC, Calabosas Hills, California, USA) 4.2 mm diameter and 13 mm length was attached to the implant mount then inserted into prepared site before setting of the resin cement with clockwise rotation until the plastic mount no longer rotate the dummy implant. The dummy implant placement was completed with torque wrench until the dummy implant top became ~1 mm above the surface of the acrylic resin block [Figure 2].
|Figure 2: The dummy implant top above the surface of the acrylic resin block.|
Click here to view
The matched matrix part of locator abutment (Legancy tmG PStm Abutment; Implant Direct LLC) was connected to the dummy implant. The abutment was initially tightened with screw driver final tightening was completed using torque wrench at 35 N/cm according to the manufacture recommendation.
Fabrication of block B
Seventy blocks are prepared to receive the metal housing with plastic cap locator attachment by using the Teflon cylinder. Self-cure acrylic resin was mixed and poured into the plastic mold and left until polymerization was completed to form the acrylic resin block B. Screw hook was embedded into top part of block B while it still soft. The center of the block B identified on lathe machine and prepared to receive the metal housing by making a round hole about 7 mm. in diameter.
After seating and hardening of the self-cure. The two blocks are separated and the extra acrylic resin was removed before taking the processing cap out of the metal housing. The black processing cap was replaced by pink cap (Implant Direct LLC) [Figure 3] by using locator core tool. The block A with matrix part of locator attachment connected to dummy implant was attached to lower member of universal testing machine (model 3345; Instron Instruments Ltd, Norwood, Massachusetts, USA). The block B with metal housing and pink locator inserts attached to the upper member of universal testing machine. Cyclic loading was done by the universal testing machine for samples of group I and group III. Each attachment was subjected to 600 cycles of insertion and removal.
Immersion in the denture cleansers
For each of cleansing solution ten blocks B with pink cap were immersed in beaker (Plasútil, Bauru, Brazil) containing 200 ml of each cleansing solution according to the manufacture's instruction for time equivalent of 6 months. The solutions were changed on daily basis.
The collected data were organized, tabulated and statistically analyzed using statistical package for the social studies version 19 (SPSS) created by IBM (Illinois, Chicago, USA). For numerical values the range mean and SD were calculated. The differences between mean values before and after intervention were tested using Wilcoxon singed ranks test. The difference of mean value between two different studied groups was tested using Mann–Whitney test. The difference of mean values between more than two groups was tested by Friedman χ2-test. The level of significant was adopted at P value less than 0.05.
| Results|| |
The results for retention values were recorded for the three tested groups in Newton (N). The mean of retention before fatigue in group I was 17.85 ± 2.15 N and after fatigue was 4.08 ± 0.88 N. The percentage of retention loss was 76.85 ± 5.86%. For group II there was significant difference between the locator attachment soaked in chlorhexidine gluconate 2% and alkaline peroxide solution (Corega tabs) in comparison to that soaked in water control (P = 0.001).
For group IIA (water control), the mean of retention before soaking was 18.97 ± 0.85 N. The mean of retention after immersion in water for equivalent of 6 months (8 h/day) was 19.01 ± 0.93 N. The percentage of retention change (−0.45 ± 7.13%) (negative value means increase in the retention; positive value means decrease in the retention). There is no significance difference of retention change before and after immersion in water (P = 0.959).
For group IIB (chlorhexidine gluconate 2%), the mean of retention value was 17.66 ± 1.57 N before immersion, after immersion for equivalent 6 month the retention was 14.9 ± 1.25 N and the percentage of retention loss was 15.14 ± 9.5%. There was significant difference before and after immersion (P = 0.005).
For group IIC alkaline peroxide solution (Corega tabs), the mean of retention value before immersion was 18.11 ± 1.14 N. The mean of retention after immersion was 13.18 ± 1.91 N and percentage of retention loss was 27.20 ± 9.81%. The difference in retention loss before and after immersion was significant P = 0.005. There was a significant difference in the percentage of retention loss for the samples immersed in water (−0.45 ± 7.13%), chlorhexidine gluconate 2% (15.14 ± 9.5%), and alkaline peroxide solution (Corega tabs) (27.2 ± 9.81%) (P = 0.001).
For group III, results of retention for group III before and after soaking in cleansers and fatigue. There was a significant difference between the locator attachment soaked in chlorhexidine gluconate 2% and alkaline peroxide solution (Corega tabs) and that soaked in water control as showed in [Table 2].
|Table 2: Comparison of mean values of retention before and after intervention among group III|
Click here to view
| Discussion|| |
Retention is a key factor for the success of complete denture treatment. Lack of retentions is the most frequent problem with existing conventional complete dentures that handicaps the patient both in mastication and in social situations due to fear of losing the dentures. Factors that can influence retentive value of nylon component of locator including occlusal function implant angulation and number of implants.
This study was focused on testing the pink locator because it was reported that it's the most popular attachment in the market this was used also by Evtimovska et al., Nguyen et al., You et al.. Chlorhexidine gluconate 2% was selected in this study because it is a broad spectrum antiseptic agent. It can inhibit Candida albicans and other common nonalbicans yeast species.
Alkaline peroxide was used in this study because it efficient denture cleanser available worldwide. It contains sodium perborate and sodium bicarbonate by dissolving these tablets in water an alkaline peroxide solution forms and sodium perborate in the structure decomposes. This peroxide solution mechanically removes debris by releasing oxygen it was used by Derafshi et al..
Seventy blokes B were done one block for metal housing and the cross ponding nylon insert to be sure that locator insert is completely immersed in the cleanser solution and for easily numbering of the blocks and the inserts to avoid the mis-numbering of the sample in reverse to Nguyen et al. and You et al.. They used plastic mesh and piece of marble to insure the complete soaking of the plastic insert of pink locator in the cleanser solution. But the numbering is very difficult in this case.
In group I: In this study the retention of the pink locator attachment was significantly decreased there was marked loss of retention after 600 cycles of insertion and removal. This may be due to wear and tear in the Nylon insert. This was in agreement with Carvalhoa et al., they found that clear nylon locator attachment registered the highest initial retention value followed by Dalbo-Ball system and pink nylon locator. After 6 months of simulating use the retention of clear nylon, the pink locator retention and Dalbo-Ball decreased. This is in agreement with our study.
On the other hand in a study carried by Aroso et al., who found significant differences in the average values of insertion/removal forces after simulating 5 years of use it was in agreement with our study. Also our results was in agreement with study carried by Srinivasan et al., who studied the influence of implant angulation and cyclic dislodging on the retentive force of two different overdenture attachments. Evitomska et al. in other study found that after the first pull there was a significant decrease of retention for the green and white locator.
In group II: As regards to the specimen immersed in water there was slight increase in the retention of locator attachments after 6 month of simulating use, but the difference was not significant this was in agreement with You et al., Nguyen et al., Kürkcüoǧlu et al. and Derafshi et al.. Because of mechanical wear of the locator inserts.
As regarding to immersion in chlorhexidine gluconate 2% there was reduction in the retention by 15.14% in subgroup IIB after 6 month of simulating use. This may be due to material degradation that caused the nylon insert to be softened. There was significant difference between subgroup II B and water control subgroup IIA. For alkaline peroxide solution (Corega tabs) there was retention loss equal to 27.20% after 6 month of simulating use. There was significant difference between subgroup IIC and water control subgroup IIA. The loss of retention may be due to material degradation that caused the Nylon insert to be softened.
The results of this study was in agreement with Nguyen et al., who founded that denture cleansers have significant effects on the retention values of pink locator attachments, in Nguyen study NaOCl decreased the retention of the locator attachments. Also locator soaked in efferdent had a slight decreased in the retention. Attachments soaked in Listerine for 8 h/day showed slight increase in the retention value. Polident regular and polident overnight had no significant on the retention of locator attachment.
Also our results was in agreement with study carried by Derafshi et al., who found that denture cleansing solutions have a significant effect on the reduction of retention value of O-ring. Corega Tabs caused 15.7% reduction in the retention value of O-rings professional Tabs caused 15% decrease in the retention value and NaOCl caused a significant decrease (48%) in the retention value of O-ring in comparison to the control group.
The results of this study was in disagreement with study carried out by Kürkcüoǧlu et al.. Our results was in disagreement with study of Watcharapichat et al., who studied the effect of polident 5 min, fittydent, chlorhexidine 0.12% and sodium hypochlorite on the retention of pink locator. Our results was in disagreement with study of Varghese et al., who studied the effect of denture cleanser on the retention of yellow hader clip.
In group III: In this group the denture cleansers showed significant decrease in the retention of locator attachment as in group II. After fatigue the retention is markedly lost as in group I. There was no significant difference between the subgroups A, B, C after fatigue. This was in agreement with You et al., finding.
In this study by comparing between the groups I and group III there was no significant difference in the retention value of group I and group III after fatigue.
The result of this study rejected the null hypothesis that there is no effect of the denture cleansers on the retention of locator of the pink locator attachments. Also that fatigue stress has no effect on the retention of pink locator attachments. The results of this study demonstrated that soaking of pink locator attachments in denture cleansers for a simulated period of 6 months significantly decrease the retention. Fatigue stress had significant decrease on the retention of pink locator attachments either with use of denture cleansers or without use of it.
| Conclusion|| |
- The fatigue (insertion and removal) affected the retention of pink locator either when not soaked in cleanser as in group I and also when soaked in the cleanser as in group III.
- Chlorhexidine gluconate 2% and alkaline peroxide solution (Corega tabs) disinfectant solutions affected retention of pink locator attachment.
- Alkaline peroxide solution (Corega tabs) affected the retention of the pink locator more than the chlorhexidine gluconate 2%.
- According to the results of this study the locator inserts should be changed every 6 months.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3]
[Table 1], [Table 2]