|Year : 2015 | Volume
| Issue : 3 | Page : 342-347
Thickness, permeability and tactile perception of commercial latex examination gloves used in dental practice
Shilpa Ashish Warhekar, Sandesh Nagarajappa, Pralhad L Dasar, Prashant Mishra, Sandeep Kumar, Swati Balsaraf
Department of Public Health Dentistry, Sri Aurobindo College of Dentistry, Indore, Madhya Pradesh, India
|Date of Web Publication||14-Sep-2015|
Shilpa Ashish Warhekar
Department of Public Health Dentistry, Sri Aurobindo College of Dentistry, Indore - Ujjain State Highway, Near MR 10 Crossing, Indore, Madhya Pradesh
Source of Support: None, Conflict of Interest: None
Introduction: Dentists are at an increased risk of being infected. Some patients may be unaware of their infected status while some patients are unwilling to tell the dentists their disease status. Gloves should be worn in almost all patient procedures. Aim: To assess association between thickness, tactile perception, and permeability of commercial latex examination gloves used in dental practice. Materials and Methods: The experimental study was conducted in Central India. A total of 600 gloves, 120 each from five brands (Kaltex, Nulife, Smartcare, Handshield, Medi-image) were used. Thickness was measured using stereomicroscope. Permeability to fluids was evaluated through 0.2% erythrosine dye. Staphylococcus aureus (ATCC-25923) was used to check for microbial permeability. Tactile sensibility was assessed by 2-point discriminator test using 2-point-calipers on 30 volunteers. Chi-square test and Binary logistic regression analysis were used. Results: Mean thickness of gloves was 0.1333 (range: 0.1028-0.1799). Dye and microbial test showed 10.6% and 43.3% permeability of gloves, respectively. No significant difference was observed among brands. Thicker gloves (0.1285-0.1542) yielded lower touch sensibility (odds ratio: 0.783, P < 0.05). Decrease in tactility was recorded in 78.6% of volunteers with gloves compared to no gloves. Conclusion: Considerable microbial permeability suggests commercial examination gloves are unsafe. Balance between thickness, permeability and touch sensation should be established to decrease permeability maintaining same touch sensibility.
Keywords: Gloves protective, latex, permeability, touch perception
|How to cite this article:|
Warhekar SA, Nagarajappa S, Dasar PL, Mishra P, Kumar S, Balsaraf S. Thickness, permeability and tactile perception of commercial latex examination gloves used in dental practice. J Indian Assoc Public Health Dent 2015;13:342-7
| Introduction|| |
Dentistry, in particular, deals with the oral cavity which is inhabited with commensal oral flora. Dentists are at an increased risk of being infected because of the potential presence of blood borne pathogens in saliva and blood, and the increased chances of needle-stick injury.  Some patients may be unaware and some patients are unwilling to tell the dentists of their infected status. These subjects can unknowingly transmit the disease to others. It was the US Centre for Disease Control and Prevention (CDC), in 1985 which first coined the phrase Universal blood and body fluid precautions.  All patients are considered potentially infectious and therefore, the same precautions should be applied on everyone. The approach is then widely known as the Universal Precautions.  This warrants use of gloves whenever there are chances of hand coming in contact with blood or any other potentially infectious materials. As saliva is considered as a potentially infectious material, this means that the gloves should be worn in almost all patient procedures and also while touching any contaminated items or surfaces. 
Gloves function as mechanical barriers that help to reduce transmission of body fluids and pathogens. This depends on absence of perforation on the gloves and integrity of the glove during use, as it can be punctured, torn, or damaged in number of ways.  Glove thickness is stated in either "mils" or "gauge."  Various guidelines are given by CDC, American Society for Testing and Materials (ASTM) and International Organization for Standardization (ISO) regarding thickness of Gloves.
Gloves scanned by electron microscopy have shown 30-50 μm holes, suggesting that viruses can penetrate these gloves.  DeGroot-Kosolcharoen and Jones investigated the permeability to water and blood of sterile latex gloves, examination latex and vinyl gloves and found greater leakage in examination gloves.  Checchi et al. revealed that numerous gloves used by dentists have a significant number of perforations even before use. They emphasized the effect of some factors, such as glove adherence to the hand rather than the hole size, on liquid entry into the gloves during use. If a chemical permeates through the glove, it may cause adverse effects to the skin or it can be absorbed through the skin and cause exposure effects elsewhere in the body. 
Tactile perception refers to perception mediated solely by variations in cutaneous stimulation.  Tactile receptorsare located in clusters around the human skin. Tactility is important while performing various dental procedures. Examination gloves are preferred by most dentists during dental cleaning, filling and other routine dental procedures in daily practice.  Report also suggests that wearing extra thin surgical gloves offers increased touch sensitivity.  It is recommended to slightly increase the examination gloves thickness as some studies report examination gloves to be permeable to fluids, chemicals and microorganisms. In doing so, the operator may experience reduced tactile sensitivity. Hence, this study was carried out with an objective to assess the association between thickness, permeability, and tactile perception of commercial latex examination gloves used in dental practice.
| Materials and methods|| |
The present experimental study was conducted in the Department of Public Health dentistry, Sri Aurobindo College of Dentistry, Indore for duration of 2 months (May-June 2013). The study sample consisted of five brands of commercially available disposable, and nonsterile latex examination gloves. These brands were conveniently selected based on their popularity of use. The brands selected were: Nulife™ , Smartcare™ , Handshield™ , Medi-image™ and Kaltex™ . Two boxes each of the above mentioned gloves were obtained from the market checking for their date of manufacture and expiry date. Each box consisted of 100 pieces of examination gloves. All the gloves were of medium size, ambidextrous, powdered, and made of latex. Of these, 30 gloves each were randomly selected for thickness measurement, microbial permeability study, dye test, and tactile sensibility assessment. The study was approved by the Institutional Review Board of Sri Aurobindo Institute of Medical Sciences and Hospital, Indore, Central India. Single examiner was trained and calibrated in the Department of Public Health Dentistry, Sri Aurobindo College of Dentistry under the guidance of an expert examiner. The kappa value (0.8) for calibration exercise showed good agreement for observations and measurement.
Glove thickness measurement
Thickness of gloves was measured using stereomicroscope. A 1 cm × 1 cm of the piece of latex gloves was obtained from the index finger region using acrylic stent. Same region and protocol were followed to obtain the samples for thickness measurement from each glove. The piece of glove was held vertical and viewed under stereomicroscope. The gradation reading in the eye-piece was recorded and converted to millimeter (mm) by multiplying with factor 0.0257. 
Permeability of latex examination gloves to fluids was evaluated through erythrosine dye in a concentration of 0.2%. Gloves were filled with prepared solution. Care was taken to ensure that no dye spilled out while filling the gloves. For control, one glove was filled with distilled water for every 5 dye filled gloves. The external surface of the glove was then washed with 10 ml of distilled water after an interval of half an hour. The resultant solution was then analyzed under digital photo-colorimeter for presence of dye. The values recorded with colorimeter for dye filled gloves were compared with control gloves. 
Microbial permeability test
Microbial permeability of sterilized latex examination gloves of each brand was evaluated using Staphylococcus aureus strain (ATCC-25923). Microorganism suspension of 10 6 cells/ml of S. aureus (ATCC-25923) in nutrient broth was prepared with the help of Densicheck.  The glove was placed into sterile conical flask with the open end rolled over the neck of the flask. Gloves filled with 200 ml of prepared cell suspension. The glove was stabilized to the conical flask with the help of sterile cotton plug. At the end of 1 h, the glove was slowly removed out of flask and the external surface was washed with distilled water. Care was taken to avoid any spill of suspension or contact with any contaminated surface. The collected water sample was streaked on 5% blood agar plates and incubated at 37°C for 24 h. At 2 h, the external surface was washed again and the samples were further tested to assess permeability.  The culture obtained on the blood agar was subjected to biochemical confirmatory test such as Gramstain,  Catalase Test,  and Coagulase Test. 
Touch perception by 2-point discriminator test
This experiment makes use of 6 adjus[Table 2]-point calipers. The experiment was carried out by a single trained and calibrated examiner. In the first stage, experiment was conducted without glove. In next stages, 30 gloves of various brands having different thickness were used randomly. Thirty volunteer dental interns were tested individually. The volunteer was blindfolded and seated with his/her right arm extended. The hand was positioned on a padded shelf with the palm facing up. The gap between 2-points of 6 calipers was preadjusted at 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, and 7 mm, respectively. The pulp of index finger was touched with calipers and the volunteer was asked to tell the experimenter how many points were felt. The process was repeated for each pair of calipers in a random sequence and the smallest gap that could be distinguished as two distinct points was recorded. 
Statistical analysis of the data was performed using Statistical Package for Social Sciences (IBM SPSS Statistics 16.5, Chicago). Chi-square test was used to assess significant difference between categorical variables. Logistic regression analysis was performed to assess the relation between touch perception (dependent) and thickness of examination gloves (independent) variable. A P ≤ 0.05 was considered to indicate statistical significance.
| Results|| |
A total of 600 gloves, 120 each from five brands were used. The minimum thickness of gloves is 0.1024 mm and maximum thickness is 0.1799 mm [Table 1]. Mean thickness of gloves was found to be 0.1332.
Of 150 gloves used for microbiologic testing, 43.3% gloves were permeable to microorganisms after 1 h and 94.3% gloves were permeable after 2 h [Table 2]. There was no statistical significant difference among the five brands of gloves at 1 h interval and 2 h interval (P > 0.05). The dye test using 0.2% erythrosine dye showed 10.6% of examination gloves permeable to dye at baseline. Almost all the examination gloves were permeable by the end of 2 h interval. Among the brands no significant difference was observed.
|Table 2: Permeability of gloves to microbiologic test and 0.2% erythrosine dye test |
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The microbial and dye permeability in relation to varying thickness of gloves is tabulated in [Table 3]. Although the permeability is seen to reduce with increasing thickness, the difference seen was not statistically significant (P > 0.05). Tactile perception using static 2-point discriminator test showed significant difference between no gloves and with gloves (Wilcoxon Signed-Rank test; P < 0.05). Tactile perception threshold of the participant was in the range between 2 mm and 3 mm for all the brands of examination gloves [Figure 1]. There was no significant difference between 2-point discrimination among the brands of examination gloves (P > 0.05 test).
|Figure 1: Static 2-point discriminator with different examination gloves|
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|Table 3: Comparison of microbial and dye permeability in relation to varying thickness of gloves |
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Variation in tactile perception with thickness of examination gloves was assessed using a binary logistic regression model [Table 4]. The touch perception was dependent variable and the gloves thickness as independent variable. In comparison with 0.1028 mm gloves, a statistically significant 4 times decrease in touch perception was observed in thicker gloves of 0.1542 mm (odds ratio [OR]: 4.0, P < 0.05). Although gloves with 0.1285 mm and 0.1799 mm showed reduced touch perception of 3 times (OR: 3) and 3.7 (OR: 3.796), respectively, the difference was not statistically significant (P > 0.05).
|Table 4: Binary logistic regression for relation between touch perception (dependent) and thickness of examination gloves (independent) |
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| Discussion|| |
For many years, latex examination gloves have been used in dentistry as universal precaution for infection control. These gloves are claimed to give better touch sensitivity along with protection against infectious agents.  According to the CDC guidelines for protective equipment the disposable gloves should be of thickness with 4-8 mil (0.1016-0.2032 mm).  The ASTM suggest a thickness of 5 mil (0.127 mm) as standard thickness for all gloves and 2 mil (0.0508 mm) for examination gloves.  The International Organization for Standardization (ISO) in its specifications for dimensions and tolerance of single use rubber examination glove has specified the thickness in the range of 0.08-0.11.  The mean thickness of commercially available examination gloves selected for this study from Indore region was 0.1333 mm (range: 0.1028-0.1799 mm). This thickness was found to be in accordance with CDC guidelines and ISO specifications.
Various methods have been used to evaluate the potential protective role of gloves, including electric conductivity test, filling test, inspection, microbiologic test, dye permeability test, radioactive tracers, bacterial and viral permeability tests and microscopic examinations.  Morgan and Adams  examined methods to evaluate the potential protective role of gloves and concluded that both dye and bacterial permeability tests are useful for detecting glove perforation and integrity. In the present study, the microbial permeability test was conducted in accordance to the method described by Martin et al.  with S. aureus cells ATCC-25923. The microbial permeability was found in 43% of gloves at 1-h interval which increased to 94.3% by 2 h. Ozata et al.  reported that passage of bacteria was not observed in latex gloves after half hour or 1 h of use, but was observed after 2 h. There was no significant difference observed among various brands for permeability of S. aureus.
Erythrosine is a dye of small molecular size, defined by the supplier as "a mixture of Disodium 2 (2457 tetra iodo 3 oxido-6-oxoxanthen-9-yl) benzoate."  In the presentstudy, erythrosine dye test as described by Morgan and Adams  using 0.2% erythrosine dye indicated 10.6% of unused gloves were permeable. Similarly, Checchi et al.  have reported 12.4% of defects among unused commercial latex gloves. These findings were higher compared to 6.6% of dye permeability among unused gloves reported by Krithika et al. 
Our study objectively measured skin pressure sensibility threshold using 2-point discrimination. Literature reports that extra thin latex gloves has lowest sensibility threshold and may provide superior touch sensibility when required.  In the present study, significant decrease in tactile perception (78.6%) was observed with gloves compared to no gloves. All the brands reported similar tactile perception threshold between 2 and 3 mm distance between static 2-point discrimination (calipers). Similar findings were reported by Bucknor et al.,  where the distance for static 2-point discrimination was between 2 and 4 mm for surgical gloves. A binary logistic regression model suggest that the tactile sensation decrease 4 times as the thickness increase from 1.028 to 0.1542 (OR: 4.0, P < 0.05). Tiefenthaler et al.  demonstrated nodifference between single use protective gloves and expensive sterile standard gloves as far as touch sensibility is concerned.
The results of the study should be carefully generalized as the study sample consisted of single lot of gloves and may not be significantly applicable to total production. The study has also not taken into consideration some of the factors that might be related to the outcome like powdered, nonpowdered and size of the gloves. Nonetheless, this study provides objective assessment of hand sensibility considering the thickness that may be an important factor to consider while studying the integrity of gloves.
| Conclusion|| |
Considerable microbial permeability suggests commercial examination gloves are unsafe. None of the brand was effective in barrier control with varying number of macro and micro defects. Quality level should be improved for more effective protection against microorganisms. The present study showed reduced touch sensitivity with increase in the thickness of examination gloves so the balance between thickness, permeability, and touch sensation should be established to decrease permeability maintaining same touch sensibility.
The authors would like to express their gratitude to the Department of Microbiology and all the volunteers for their cooperation and active participation in the study.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2], [Table 3], [Table 4]