|Year : 2023 | Volume
| Issue : 1 | Page : 65-70
Evaluation of dimensional stability, compressive resistance, and detail reproduction of thermoplastic resin (BDIMPRESS), elastomeric and composite bite registration material: An in vitro study
Sai Kiran Koppolu1, PS Manoharan1, E Rajkumar1, G Ezhumalai2
1 Department of Prosthodontics, Indira Gandhi Institute of Dental Sciences, SBV University, Puducherry, India
2 Sr. Statistician and Research Consultant, Sri Balaji Vidyapeeth University, NODAL Officer, AISHE, Puducherry, India
|Date of Submission||24-Mar-2022|
|Date of Decision||15-May-2022|
|Date of Acceptance||08-Jul-2022|
|Date of Web Publication||29-Dec-2022|
P S Manoharan
Department of Prosthodontics, Indira Gandhi Institute of Dental Sciences, SBV University, Puducherry, India. E-mail: [email protected]
Source of Support: None, Conflict of Interest: None
Aim: The fabrication of an accurate prosthesis depends mainly on precise recording of the maxillo—mandibular relationship of the patient and transferring it to the articulator. BDIMPRESS is a new thermoplastic material that has been proposed as a potential material to be used as an inter-occlusal registration, but there has been no literature evidence regarding its application as a bite registration. The main purpose of this study is to evaluate and compare the dimensional stability, detail reproduction, and compressive resistance of new interocclusal recording material with other two commonly used materials.
Settings and Design: In Vitro Comparative study.
Materials and Methods: The study was conducted according to ADA Specification standards of testing for dimensional stability, detail reproduction and compressive resistance. Specimens were prepared for three different materials (Thermoplastic resin, Polyvinyl siloxane, and Bis- acrylic) with 12 samples each.
Statistical Analysis Used: One way ANOVA was done for statistical analysis.
Results: Polyvinyl siloxane material was dimensionally stable (mean at 1 hr: 24.928 mm; 24 hrs: 24.919 mm & 48 hrs: 24.912 mm) followed by Bis- acrylic material (mean at 1 hr: 24.851 mm; 24 hrs: 24.825 mm & 48 hrs: 24.815 mm). On one way ANOVA, strong significance was observed between groups (P = 0.00). Thermoplastic resin showed higher amount of detail reproduction with 10 (out of 12 samples) samples showing satisfactory results. While bis- acrylic material showed the least compressive resistance (Strain %: 0.484%; Displacement- 0.0990mm). One-way ANOVA showed presence of significance between the groups (P = 0.024).
Conclusion: Polyvinyl siloxane showed superior dimensional stability, thermoplastic resin showed better detail reproduction and bis- acrylic showed high resistance to compression over other materials.
Keywords: Compressive resin, dimensional stability, interocclusal recording material, thermoplastic resin
|How to cite this article:|
Koppolu SK, Manoharan P S, Rajkumar E, Ezhumalai G. Evaluation of dimensional stability, compressive resistance, and detail reproduction of thermoplastic resin (BDIMPRESS), elastomeric and composite bite registration material: An in vitro study. J Indian Prosthodont Soc 2023;23:65-70
|How to cite this URL:|
Koppolu SK, Manoharan P S, Rajkumar E, Ezhumalai G. Evaluation of dimensional stability, compressive resistance, and detail reproduction of thermoplastic resin (BDIMPRESS), elastomeric and composite bite registration material: An in vitro study. J Indian Prosthodont Soc [serial online] 2023 [cited 2023 Feb 6];23:65-70. Available from: https://www.j-ips.org/text.asp?2023/23/1/65/365937
| Introduction|| |
The fabrication of an accurate prosthesis depends mainly on precise recording of the maxillomandibular relationship of the patient and transferring it to the articulator. There are high chances of variations occurring during vertical, anteroposterior, and mediolateral positions. To achieve an accurate relation, a medium is essential to articulate the casts in the correct maxilla-mandibular relationship and in programming the articulator. Hence, interocclusal registration materials are essential., The interocclusal records are like impression materials that are specially modified to record the occlusal relationship of the human oral cavity and transferring it to the articulator. Interocclusal registration material is mainly indicated in certain conditions such as completely edentulous, worn-out conditions, full mouth rehabilitations, and distal extension-partially edentulous where reference stops are not present. Any inaccuracy in interocclusal records leads to occlusal errors in the final prosthesis.,
Bite registration is one of the essential steps in obtaining a proper occlusal relation and as well promotes the health of temporomandibular joint and other supporting structures. The main objective of these records is to reproduce the details (i.e., cuspal morphology), withstanding the compressive forces, maintain dimensional stability (during the time of transport), have sufficient wettability and have easy handling properties. Initially, waxes were used; later, zinc oxide-eugenol pastes and elastomeric materials (polyvinyl siloxane [PVS], polyether) were used extensively. Usage of bis-acrylic materials has also been applicable for recording the bite.,,
There are plenty of materials available in the market, and a clinician should be able to choose the right material, for which one should be aware of the composition, techniques, properties, and factors affecting the interocclusal recording materials to produce predictable results. In the past decade, multiple studies were done on properties such as accuracy, viscosity, thermal conductivity, setting characteristics, detail reproduction, elasticity, compressive resistance, and dimensional stability of different interocclusal recording materials.,, The choice of other two materials (Ivoclar CAD-Bite and DMG Luxabite) used for the study was made referring to the previous studies.
With new materials, the accuracy in achieving good results has been increasing. A new thermoplastic material (BDIMPRESS) has been proposed to be used as custom impression, custom trays, functional border molding, and as an interocclusal registration. However, there has been no literature evidence regarding its application as a bite registration.
This study was done to evaluate the compressive resistance, dimensional stability, and detail reproduction of three different interocclusal recording materials such as bis-acrylic (DMG Luxabite), PVS (Ivoclar CAD-Bite), and thermoplastic resin (BD IMPRESS).
| Materials and Methods|| |
The equipment and materials used for the study were described in [Table 1] and [Table 2]. This study was approved by The Institutional Review Board (IRB reference number-IGIDSIEC2021NRP03PGSKPRI.
Fabrication of die for dimensional stability and detail reproduction
A master die was made according to the Revised American Dental Association specification number19 for nonaqueous, elastomeric dental impression materials. It consists of three stainless steel parts. The first part is described as a ruled block with three vertical lines differing in widths (50, 20, and 75 μm, respectively) and two horizontal lines with 75 μm width. The distance between the intersection of lines (vertical and horizontal) is 25 mm, which is used as a criterion for checking the dimensional stability of the samples. The vertical lines with three widths are essential for assessing the detail reproduction of the samples. The ruled block has a base with 31-mm height, 38-mm diameter and raised the part has 3-mm height and 30-mm diameter. The second part was a hollow impression material mold for the injection of material which is 6 mm in height and 30 mm of inner diameter. When the hollow impression material mold was snuggly fit over the ruled block, it provides space of 3 mm for the material to be injected. This gives an accurate thickness of 3 mm for all the samples fabricated. The final part was the riser which was used to cover the mold after injecting the material into the mold. It was of 3 mm in height and 29.97 mm in diameter.
Fabrication of die for compressive resistance
A master die was done using a split stainless steel hollow mold. One hollow mold, which has an inner diameter of 12.5 mm and a height of 20 mm, was retained in the second hollow mold, which has a 5° tapering. The second mold has an outer diameter of 35 mm, inner diameter at the base is 22 mm, and inner diameter at the apex is 26 mm. It has a height of 16 mm.
A proper application of lubricating agent was done on the inner surfaces of the molds for easy retrievability of the material once it is set. After the application of adequate lubricating agent over the molds, the impression material mold was snugly fitted into the other split mold. The material was mixed according to the manufacturer's instructions and injected into the impression material mold. After the placement of the material, riser was placed over it for obtaining the proper shape and size of the sample. Polyvinyl silicone material (Ivoclar Vivadent CAD-Bite) was supplied in auto-mixing cartridges of 1:1 ratio, which were dispensed using dispensing gun (1:1/1:2) with the attachment of mixing tips to the cartridge. The tips were placed into the mold, and the material was injected into the impression material mold and covered with riser over it. Bis-acrylic material (DMG Luxabite) was supplied in auto-mixing cartridges of 1:10 ratio and dispensed using a 1:10 dispensing gun with the attachment of mixing tips to the cartridge. The same manipulative method was applied for bis-acrylic material using the cartridge, dispensing gun, and mixing tip. Whereas thermoplastic material (BDIMPRESS) was supplied as small white color beads, which become soft and moldable when placed in boiling water. The adequate number of beads was placed in boiling water, and once it transformed into a clear moldable state, it was taken out with a clear instrument and manipulated with fingers by applying Vaseline to avoid sticking of the material to the fingers. After manipulation, it was placed into the mold, and riser was compressed over the material to make the sample uniform in dimensions. The samples were allowed to set for 3–5 min before retrieving them from the mold. The assembly was then transferred to water bath with 32°C. For each material, 12 samples were made for compression analysis, and another 12 samples were made for dimensional stability measurements using their respective molds.
Testing of the samples for compressive resistance
The testing of samples for compressive resistance involves the application of a series of loads and checking the compressive strain (%). Initially, the length of each sample was measured using a digital Vernier caliper. The testing was done using a Modular Compact Rheometer (MCR) 702 with a linear drive for Dynamic Mechanical Analysis (DMA), AntonPaar, Austria. The fabricated samples were placed in water bath at 32°C until it sets. After setting, the sample was removed from the mold and placed between two 25 mm parallel plates for application of load [Figure 1].
|Figure 1: Sample compressed between two parallel plates in MCR 702 with DMA. MCR: Modular Compact Rheometer, DMA: Dynamic mechanical analysis|
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The test was conducted under three intervals and two loads. Initially, a constant load of 100 g/cm2 (9.8kPa) was applied for 60 s. The first reading (A) of linear compressive strain (%) was recorded after the 30s of initiation of the load. After the 60s, the load was gradually increased to 1000 g/cm2 (98kPa) in 10 s. The 30s after initiation of second load, second reading (B) was recorded. The compressive strain (%) was calculated by subtracting readings A and B for each sample.
Testing of the specimens for dimensional stability
The fabricated samples were scanned using a scanner EPSON at 2400dpi resolution. The scanned image was analyzed using ImageJ image processing software. The distance between the intersection of vertical and horizontal lines was assessed after 1, 24, and 48 h of sample fabrication. All the three readings were measured to the nearest 0.005 mm.
Testing of the specimens for detail reproduction
Detail reproduction was assessed using the same sample which was fabricated for measuring dimensional change. The reproduction of three lines widths for the full length of 25 mm was assessed using ImageJ image processing software [Figure 2].
| Results|| |
The data obtained after testing the samples for compressive resistance, dimensional stability, and detail reproduction were statistically analyzed using one-way analysis of variance (ANOVA). The clinical significance among the groups was also mentioned. Mean, standard deviation, and 95% confidence with upper and lower borders for all the groups were discussed in descriptive tables.
Compression resistance analysis
DMG Luxabite showed better resistance to compression (compressive stain % and displacement [mm]), followed by BDIMPRESS, while Ivoclar Virtual CAD Bite showed high values which explain that they had less resistance to compression [Table 3] and [Table 4].
|Table 3: Comparison of compressive strain (%) of three interocclusal materials using ANOVA|
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|Table 4: Comparison of displacement on compression (mm) between three interocclusal materials using ANOVA|
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Ivoclar Virtual CAD Bite showed better dimensional stability at 1 h, 24 h, and 48 h, followed by DMG Luxabite, while Group I (BDIMPRESS) showed the least values of dimensional stability [Table 5].
|Table 5: Statistical analysis for dimensional stability length wise (mm) at different time intervals for three interocclusal materials using ANOVA|
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Thermoplastic resin (BDIMPRESS) showed good amount of reproduction with 10 (out of 12 samples) samples showed satisfactory results, while Bis- Acrylic (DMG Luxa-Bite) showed least detail reproduction 6 (out of 12 samples) were satisfactory [Table 6].
|Table 6: Descriptive table on detail reproduction among three interocclusal materials groups|
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| Discussion|| |
The basic objectives for occlusal rehabilitation are optimum oral health, functional efficiency, oral comfort, and esthetics. The recording medium should be accurate and dimensionally stable to transfer the relationship of jaws to the casts on an articulator. Various methods of recording maxillomandibular relationships are graphic, functional, cephalometric, and direct interocclusal records. Direct interocclusal records are commonly used to record the maxillomandibular relationship of dentulous casts. The recording material, which is soft, initially occupies the spaces between teeth and hardens. The set material, along with the casts, are then transferred onto an articulator.,
The main purpose of this in vitro study was to compare the interocclusal recording materials (thermoplastic resin, poly vinyl siloxane, and bis-acrylic). Two materials (PVS and bis-acrylic) commonly used in the clinical scenario were compared with a new material (thermoplastic resin) which was claimed to have superior properties. The three materials were tested for compressive resistance, dimensional stability, and detail reproduction. The compressive resistance was measured in strain % and displacement (mm). Dimensional stability was assessed at three different time intervals (1 h, 24 h, and 48 h) by calculating the shrinkage of the line (length wise), which was reproduced on the sample. The measurements were assessed in millimeters. Whereas detail reproduction was evaluated by checking the reproducibility of the lines as satisfactory and unsatisfactory among the samples.
The samples were assessed using MCR 702 with DMA by AntonPaar for compressive resistance., ImageJ is an Image processing software that was used in this study to evaluate dimensional stability and detail reproduction of the samples.,
A total of 36 samples were fabricated (12 samples per material) for evaluating compressive resistance. Another set of 36 samples was fabricated for evaluation of dimensional stability and detail reproduction. The sample size of 12 in each group was calculated using the sample size formula and by referring to similar study articles., The statistical analysis used for the study are mean, standard deviation, one-way ANOVA, and Bonferroni correlation.
The null hypothesis of the study (there is no difference in the dimensional stability, compressive resistance, and detail reproduction between thermoplastic interocclusal registration material (BDIMPRESS) and elastomer (Ivoclar Virtual CAD-Bite) and composite (DMG Luxa-bite) bite registration materials) was rejected. Strong significant difference was present among the groups, which indicates the high power for the study. Bis-acrylic material (DMG Luxa bite) showed the least compressive resistance (Strain%−0.484%; Displacement −0.0990 mm), followed by thermoplastic resin (BDIMPRESS) (Strain % −0.60253%; Displacement −0.12275 mm). One-way ANOVA showed the presence of significance between the groups (P = 0.024), and Strong significance was observed between bis-acrylic and PVS material. On the other hand, PVS (Ivoclar Virtual CAD-Bite) material was dimensionally more stable with less shrinkage in relation to time (mean at 1 h: 24.928 mm; 24 h: 24.919 mm and 48 h: 24.912 mm), followed by Bis-acrylic (DMG Luxa-Bite) material (mean at 1 h: 24.851 mm; 24 h: 24.825 mmand48 h: 24.815 mm). Thermoplastic resin (BD IMPRESS) was the least dimensionally stable among the three materials. On one-way ANOVA, strong significance was observed between groups (P = 0.00), while Bonferroni (post hoc) test elaborated strong significance on the comparison of all the groups individually (P < 0.001). Significance was also observed within the groups at three different time intervals. On evaluation for detail reproduction, thermoplastic resin (BDIMPRESS) showed a good amount of reproduction with 10 (out of 12 samples) samples showed satisfactory results, while Bis-Acrylic (DMG Luxa-Bite) showed the least detail reproduction (6 out of 12 samples were satisfactory). All the values were statistically significant, but its clinical relevance should be evaluated in future studies.
Similar studies which were done evaluating compressive resistance and dimensional stability are: Nagrath et al. compared four interocclusal records for compressive resistance. He concluded that PVS (Virtual CAD-Bite) had greater resistance to compression with the least amount of distortion. Prajapati et al.(2018) conducted an in vitro study to evaluate dimensional stability among PVS, bite registration wax, and zinc oxide-eugenol bite registration paste. PVS showed less linear change, followed by Zinc oxide eugenol paste and bite registration wax. In 2020, Choudhary evaluated the compressive resistance of Zinc oxide eugenol paste, PVS, and Polyether. Samples were made of three different thicknesses (2 mm, 5 mm, and 10 mm). A constant load of 25 N was applied for 1 min and deformation was measured after 60 s of loading. Clinical significance was observed between the materials. There was a decrease in compressive resistance with an increase in thickness of the material. PVS showed greater resistance to compression compared with other materials. In another study comparing PVS, bis- acrylic and alu-wax for their dimensional stability, it concluded that PVS and bis acrylic had better dimensional stability. It was concluded that PVS and bis-acrylic had better dimensional stability. There are many studies supporting that PVS had better compressive resistance, dimensional stability, and detail reproduction.,,,
The main strength of this study was the standardization followed for the fabrication of samples and the testing protocol used. The samples were assessed using superior machinery (MCR 702 AntonPaar and ImageJ software) for the evaluation of compressive resistance, dimensional stability, and detail reproduction. Some of the limitations of the study are there was no simulation of intra-oral temperature and saliva during the setting of the materials and no application of nonaxial loading. Hence, there is a need for further clinical trials to evaluate the time needed for setting and how much time is needed after maxillomandibular registration to the articulation of the casts without affecting the dimensional stability of the materials and also to evaluate the compressive resistance in nonaxial loading.
| Conclusion|| |
Within the limitation of the study, the following conclusions may be drawn:
- Bis-acrylic interocclusal recording material showed high resistance to compression, whereas PVS had the least compressive resistance
- PVS interocclusal recording material is dimensionally more stable. Thermoplastic resin showed the least dimensional stability
- Thermoplastic resin interocclusal recording material showed better detail reproduction, whereas bis-acrylic showed poor detail reproduction.
This thermoplastic resin can be used as one of the interocclusal recording materials. It has good advantages of precise detail reproduction and good compressive resistance. It can also be compared with other existing materials.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2]
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6]