|Year : 2020 | Volume
| Issue : 7 | Page : 19-23
Exposure of methacrylate from acrylic dust generated by removable orthodontic appliance fabrication in Surabaya, Indonesia
Sianiwati Goenharto, Elly Rusdiana, David F Putra
Department of Health, Faculty of Vocational Studies, Universitas Airlangga, Surabaya, Indonesia
|Date of Web Publication||17-Jan-2020|
Department of Health, Faculty of Vocational Studies, Universitas Airlangga, Srikana 65, Surabaya 60286.
Source of Support: None, Conflict of Interest: None
Aims and Objectives: The finishing and polishing of removable orthodontic appliances can produce acrylic dust containing methyl methacrylate, which is potentially prejudicial to health. The aim of this study was to determine the average amount of acrylic dust produced by the finishing and polishing processes involved in removable orthodontic appliance fabrication and the associated risk factors. Materials and Methods: This descriptive observational study constituted samples of 93 orthodontic appliances (62 upper orthodontic plates and 31 lower orthodontic plates) manufactured by sixth semester students of the Dental Technology Study Program, Universitas Airlangga, Surabaya, Indonesia, between February and May 2016, which satisfied the criteria. The amount of acrylic dust produced was calculated on the basis of the difference between the weight of an orthodontic plate after acrylic processing and the weight after finishing and polishing. Data were tested statistically using Kolmogorov–Smirnov test, Mann–Whitney test, and Hosmer–Lemeshow test with P value < 0.05 and performed with the Statistical Package for the Social Sciences (SPSS) software, version 24.0. Results: The results showed that the average acrylic dust produced in the fabrication of a removable orthodontic appliance was 1.23g (range, 0.29–3.54g). The average acrylic dust produced by the upper orthodontic plate (1.34g) was greater than that of the lower plate (0.94g). Results also showed that the finishing process produced more acrylic dust (0.94g) than the polishing process (0.27g). Conclusion: The acrylic dust produced by the removable orthodontic appliance production process undertaken by sixth semester Dental Technology students at Universitas Airlangga, Surabaya, Indonesia, had an average weight of 1.21g. The finishing process produced more acrylic dust in comparison to the polishing process. Students’ skill in producing orthodontic appliances and orthodontic plate design represents a major factor affecting the amount of acrylic dust produced.
Keywords: Acrylic Dust, Acrylic Orthodontic Plate, Finishing and Polishing
|How to cite this article:|
Goenharto S, Rusdiana E, Putra DF. Exposure of methacrylate from acrylic dust generated by removable orthodontic appliance fabrication in Surabaya, Indonesia. J Int Oral Health 2020;12, Suppl S1:19-23
|How to cite this URL:|
Goenharto S, Rusdiana E, Putra DF. Exposure of methacrylate from acrylic dust generated by removable orthodontic appliance fabrication in Surabaya, Indonesia. J Int Oral Health [serial online] 2020 [cited 2020 Apr 1];12, Suppl S1:19-23. Available from: http://www.jioh.org/text.asp?2020/12/7/19/276088
| Introduction|| |
There are three varieties of appliances used for orthodontic treatment, namely fixed appliances, removable appliances, and a combination of the two. Removable orthodontic appliances constitute devices that can be inserted and extracted by the patients themselves, which consist of an active component, a retentive component, and an acrylic base plate. The materials used for creating removable orthodontic appliances are generally self-cured acrylic or auto-activated acrylic resin. This material is more economical and requires a shorter working time. However, it also has certain disadvantages, among others, such as a higher tendency to porosity, lower impact strength than heat-cured acrylic resin, and the production of a higher number of residual monomers. Self-cured acrylic consists of polymer powder and monomeric liquid. This liquid contains methyl methacrylate, whereas the basic ingredient in polymer powder is polymethyl methacrylate.
According to Serra et al., one factor that should be taken into account when manufacturing removable orthodontic appliances before their being used by patients is the finishing and polishing process. This process is undertaken by dental technicians to smooth rough and sharp surfaces that can lead to oral irritation and food debris accumulation on the surface of the orthodontic appliances. Rashid et al. stated that the production process and the use of orthodontic plate materials can induce allergies, respiratory disease, and dermatological problems in dental technicians. The atmosphere in dental laboratories can be subject to dust pollution as the processes carried out there, particularly those of sand blasting, grinding, and polishing, generate significant amounts of dust. Grinding acrylic plates during the manufacture of removable orthodontic appliances produces dust consisting of particles of various sizes. Dust consisting of extremely fine particles is more dangerous as the relative ease with which it deeply penetrates the lungs can cause serious health problems. If dental technicians do not use appropriate personal protective equipment, dust and other impurities can damage their health while also causing environmental pollution.
The apparent absence of research measuring the amount of acrylic dust produced when manufacturing removable orthodontic plates acted as the incentive for conducting of this research. Dental technicians need to be aware of the degree of dust production to enable them to avoid possible negative effects by working efficiently with specific materials that enable the production of orthodontic plates with minimal dust waste.
The purpose of this study was to determine the average amount of acrylic dust produced from the finishing and polishing processes within the manufacture of removable orthodontic plates.
| Materials and Methods|| |
This study was approved by the Commission for the Ethical Health Research of the Faculty of Dental Medicine, Universitas Airlangga (251/HRECC.FODM/IX/2018). The research design was used as descriptive observational in nature. The sampling technique was purposive in that the selection of inclusion criteria research subjects was based on their satisfying the eligibility criteria of producing orthodontic plates without reparation process or the addition of Coffin springs. In this study, the numbers of samples taken were all orthodontic plates produced by third year dental technician students of the Faculty of Vocational Studies, Universitas Airlangga, Surabaya, Indonesia, between February and May 2016. Each student created two maxillary plates and one mandibular plate. The exclusion criteria were samples that had undergone preparation process or another additional orthodontic appliances [Figure 1].
|Figure 1: Illustrations of acrylic processing layer by layer (left) and finishing process to remove excess acrylic (right)|
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Processing: After the working model had been coated with separator material, the acrylic filling process was carried out using the layering technique. This involved sprinkling monomer liquid (Ortho Resin, UK) and powder/polymer (Ortho Resin, S. Court, England) thinly, evenly, and layer by layer on to the working model until it attained even distribution and the desired thickness.
Polymerization and weighing: After completion of the acrylic filling, the working model was placed in Polyclav (Remanium; Dentaurum, Ispringen, Germany) for 15min at a temperature of 50°C and a pressure of 2 atmospheres. This process aimed to reduce porosity resulting from trapped air. The orthodontic devices were then released from the working model. Approximate results for the orthodontic plate were subsequently obtained with it being placed on a scale (Idealife Pocket Scale, China), and the weight was recorded.
Finishing, polishing, and weighing: The process of grinding was performed to reduce and form the plate parts to the desired shape and thickness, using a handpiece (Saeshin Strong 204, Dasa-eup, Korea), various types of acrylic burs (Dentaurum), and scrub paper (Fuji Star, China). At this stage, the surface of the orthodontic plate was rendered smooth and even. On completion of the finishing process, the orthodontic device was weighed once. Polishing was then conducted using a machine (Silfradent, Santa Sofia, Italy) equipped with a felt cone number 3 2" × 1" (Keystones, Colorado), an abrasive pumice, and kryte brush rendering the surface of the orthodontic plate smooth and shiny. After polishing, the orthodontic device was weighed.
Statistical analysis: Data were tested statistically using Kolmogorov–Smirnov test, Mann–Whitney test, and Hosmer–Lemeshow test with P value < 0.05 and performed with the Statistical Package for the Social Sciences (SPSS) software, 24.0 edition (SPSS, Chicago, Illinois).
| Results|| |
In this study, the samples consisted of a total of 116 orthodontic plates manufactured by 31 sixth-year dental technician students attending Universitas Airlangga, Indonesia. However, of the 116, those meeting the criteria totaled 93, consisting of 62 units of maxillary orthodontic plates and 31 units of mandible orthodontic plates [Table 1].
|Table 1: The average amount of acrylic dust (grams) produced on the finishing and polishing orthodontic plates by 31 dental technician students, Maxillary plate (p < 0.05), Mandible plate (p < 0.05)|
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The results relating to the amount of acrylic dust produced by the process of making removable orthodontic plates and by the type of jaw can be seen in [Figure 2] and [Figure 3].
|Figure 2: The average amount of acrylic dust (grams) produced on the finishing and polishing orthodontic plates according to the type of jaw|
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|Figure 3: The average amount of acrylic dust (grams) resulting from the processing phase of orthodontic plates|
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According to the results, finishing produces more acrylic dust than polishing (P = 0.007, P < 0.05) [Table 2]. Similarly, the amount of acrylic dust produced from the maxillary orthodontic plate is significantly greater than that of the lower jaw (P = 0.000, P < 0.05).
|Table 2: The mean and standard deviation amount of acrylic dust (grams) produced on the finishing and polishing orthodontic plates by 31 dental technician students|
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The P value of polishing dust was greater than 0.05 (P = 0.083) and considered not significant against the type of jaw [Table 3]. Therefore, the equation of relationship between dust amounts of manufacturing process against the type of jaw is as follows:
|Table 3: The P value and odds ratio from amount of acrylic dust (grams) produced on the finishing and polishing orthodontic plates by 31 dental technician students|
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Y = 1.376 – 2.369 Maxillary jaw.
| Discussion|| |
One of the most important considerations when creating orthodontic plates is patient comfort. The orthodontic plate surface must, therefore, be smooth and shiny, characteristics achieved through the finishing and polishing processes, which generate dust that can endanger health. According to Ishikawa et al., during the finishing and polishing processes, the eye muscles and fingers are very focused on grinding several specific removable appliance parts with the result that acrylic dust often enters and irritates the eyes. The vibration of the handpiece can also produce extra tension, which can negatively affect the nerves in the hand.
To the best of our knowledge, there is no study relating to our study, to measure the amount of acrylic dust from finishing and polishing of acrylic plate. During this research, each student produced two upper orthodontic plates and one lower orthodontic plate. From [Table 1], it is evident that the average acrylic dust produced during the finishing and polishing processes of all student samples was 1.21g, within a range of 0.29–3.54g. This variation may be related to the relative skill of the students in performing acrylic processing. If the filing process produces too much acrylic or exceeds the plate design limit, there will also be more dust generated. Orthodontic plates, which are too large also require extra effort to reduce their size, rendering the process inefficient.
The results of this study also showed that 14 of 31 students produced amounts of acrylic dust greater than 1.21g or exceeded the average for all samples. In terms of overall results, maxillary plates produced more dust than mandible plates. The largest amount of maxillary acrylic dust was generated from maxillary plate (3.54g). The maxillary plate design included anterior transverse expansion with an excessively thick screw area, which, consequently, required excessive grinding. The other design producing higher amounts of dust was that of a maxillary plate with posterior bite-plane and screw expansion. The acrylic infringed on the plate boundary, requiring it to undergo further grinding. The screw expansion design necessitated a splitting process, which increased the volume of dust produced.
The highest amount of acrylic dust in the lower jaw was obtained from a specific design, the Coffin spring transverse expansion design (1.46g). The acrylic processing appeared to have been excessive, resulting in a thicker acrylic plate. In addition, this design required plate splitting, which generated more acrylic dust.
According to the results outlined above, a dental laboratory environment may jeopardize the well-being of technicians. According to an Indonesian Ministry of Health regulation, laboratory layout must meet health and safety regulations, while incorporating strategic room design. Laboratory maintenance should also follow strict operational standard procedures, with the maintenance and storage of tools and materials being in accordance with the safety principles. The dental technician needs to wear appropriate health and safety equipment such as personal protective gear (masks, glasses, gloves, and suits), fire extinguishers, first aid kits, and other waste treatment facilities.
Dental technicians should work in a disciplined manner, being aware of and paying attention to those factors potentially causing harm or accidents and obeying rules to avoid accidents. For this reason, regulations must be observed by all those involved in laboratory work. In addition, a harmonious relationship between laboratory staff is required to improve cooperation and promote successful working.
The weight of the acrylic dust generated by dental technician students in Surabaya, Indonesia, during the process of manufacturing removable orthodontic appliances averaged 1.21g. The finishing process produced more acrylic dust than the polishing process. Student skill and orthodontic plate design were factors also influencing the amount of the acrylic dust generated, therefore the skill of manufacturing orthodontic plate needs to be improved and the usage of personal protective gear is needed to reduce acrylic dust produced from finishing and polishing phase.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
We would like to thank the Department of Dental Public Health, Faculty of Dentistry, Universitas Airlangga, for statistical help.
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[Figure 1], [Figure 2], [Figure 3]
[Table 1], [Table 2], [Table 3]