Effect of propolis on the mechanophysical properties of addition silicon dental impression material

Preparation of propolis disinfectant solution

Propolis (1.6 grams) (Alsajad Beehives, Salah Aldeen in Iraq) were added to a container, and 100 ml of 96% ethanol was added to make propolis (16 mg/ml). The top was shut, for two weeks, the mixture was shaken twice a day in a dark, warm environment (room temperature). Then, the combination was filtered through a clear, incredibly fine paper filter (Qualitative Filter Paper 15 cm, China). The filtrate was a dark brown to slightly reddish liquid that was clear and pure. It was kept in airtight, clean, dark containers.^23,24

Preparation of impression specimens for linear dimensional change

Putty Soft Addition Silicon Impression Materials (Zhermack, DC, Germany) were utilized To prepare the test impression specimens. Apparatus was created using the software program 3D max 2022 (1) and then printed using a 3D printer according to ISO 4823:2015 standard for testing elastomeric impression materials. The apparatus consists of four parts: the first is a ruled test block with five v-shaped lines etched into it. three vertical lines (A 50 m, B 20 m, and C 75 m) and two horizontal D1 and D2 with a depth of 75 m. The length of vertical lines between D1 and D2 is 25 mm, and this distance is used to measure the linear dimensional change. The second component is a ring mold that acts as a mold for a dental impression, and the third component is a riser. The slit mold used to test for compatibility with gypsum was the fourth component.

In order to normalize the test block’s temperature to intraoral temperature, it was immersed in a water bath at 35°C for 15 minutes.^25,26 In accordance with ISO 4823:2015, impression material was injected and slightly overfilled the ring mold onto the test block, then covered with polyethylene sheet, the assembly was then placed back in a water bath to simulate oral temperature, a glass slab was placed on top, and a one kilogram of weight was added to the assembly to simulate the pressure of the hand on the tray.²⁷ According to ISO 4823:2015 for lab testing, the specimens were taken out of the ring mold two minutes after the manufacturers recommended minimum removal time, and any excess was cut away using blade number 15²⁶ and then washed for 15 seconds under running distilled water as directed by the manufacturer.

Evaluation of linear dimensional change

In the study of Oliveira et al. (2021) elastomeric materials and silane-containing alginate were molded using a stainless-steel cast. Three distinct approaches were used to measure the horizontal linear distances in the stainless steel cast: a measuring microscope, a digital caliper, digitization using a digital camera and measuring the distances using ImageJ software.

Digital imaging was advised by Oliveira et al. (2021), this method showed insignificant difference from microscope measurements, which was frequently employed in investigations. The use of digitalized images for distance measurements using software provides a number of advantages over measuring using a microscope that should be highlighted, such as the reduced operational costs, the ability to store the photos for the measurements at any time the operator chooses, and the decrease in the average measurement time, To determine the distance between D1 and D2 on the specimen, this method was employed in this study.

After the specimens had been photographed immediately following disinfection, line B between line D1 and Line D2 was measured using the ImageJ computer program (ImageJ 1.53k, National institutes of health USA).²⁸ Three measurements were made for each impression specimen at various periods, and the means of those values were calculated. The test block was measured three times, with a mean length of 25 mm.

This value served as each specimen’s initial (pretreatment) measurement (L1). According to ISO 4823:2015, the calculation that was utilized to determine the percentage of linear dimensional change for each specimen was as follows:

L1 is the reading of line B on the test block, and L2 is the reading of line B on the impression specimen following disinfection.

Evaluation of details reproduction

Elastomeric impression materials used to create precision castings must meet ISO 4823:2015’s requirement that they can replicate fine detail to a level of 20 m or less, which is a precise and comparable method. In this study, an ISO 4823:2015 standard apparatus was used to limit the variations associated with the uncontrollable factors, allowing for a more accurate and comparable assessment of the impression material’s capacity to replicate surface detail. The same image used to assess linear dimensional change was also utilized to assess details reproduction Figure 1, where line B was examined by two observers in order to determine the surface detail score using a ranking system developed by Owen to evaluate how well line B was reproduced in the specimens, The specimens were ranked using four scores²⁹:

Figure 1. Evaluation of details reproduction on the addition silicon impression specimens (Score 1).

Score 1: The whole line was sharply and clearly duplicated between the markings(D1 and D2).

Score 2: The line is distinct for more than 50% of its length, less than 50% is unclear.

Score 3: The line is obscure over 50% of its length, obscure over less than 50% of its length, or totally visible but rough and imperfect.

Score 4: Disparate along the length and pitted, rough, or blemished.

preparation of impression specimens for compatibility with gypsum products

After preparation of the impression specimen, which was done in the same manner as for the first two tests stated, the impression specimen was then disinfected according to its group then rinsed with distilled water, then the impression specimen was secured to the ring mold, put over the riser, and gently squeezed to force the specimen up until the ruled surface of the specimen is level with the ring mold’s top. Then, the slit mold was attached to the ring mold. As advised by ISO 4823:2015, a slurry of type IV die stone (Zhermack, Italy) was poured over the impression. Following the manufacturer’s instructions, the gypsum slurry was created by mixing 25 ml of water with 100 g of stone for 60 seconds. After 45 minutes, the gypsum cast specimen was taken out of the mold.³⁰

Evaluation of compatibility with gypsum products

Each gypsum specimen was removed from the mold, photographed, and the image was magnified Figure 2. all gypsum specimen was assessed using ISO 4823:2015 with a modification by assigning grades to all prepared gypsum specimens when assessing the 50 μm line on the gypsum.³¹

Figure 2. Evaluation of compatibility with gypsum products on the addition silicon impression specimens (Score1).

Score 1: sharp continuous line, smooth cast surface

Score 2: continuous line, loss of sharpness and small pits on the surface

Score 3: deterioration of line detail, more extensive cast surface pits and porosity

Score 4: rough appearance, loss of line continuity, pronounced porosity and deterioration of surface.

Preparation of impression specimens for wettability and surface roughness

The employed mold was shaped like a disc, 2 mm thick, 20 mm in diameter.³² Following the guidelines provided by the manufacturers, thirty specimens of addition silicon impression materials were made for each test. Propolis (16 mg/ml, freshly made) and sodium hypoclorite (5.25%, AQUA, Turkey) were both used as disinfectants. The mold was set on a plate of clear glass before it was overfilled. A second plate of a comparable size was put on the apex of the mold, and pressure was applied for five seconds. After a specified period of time, the specimens were withdrawn from a water bath that was kept at 35 °C to aquivalent the temperature of the patient mouth.³³

Evaluation of wettability

All specimen surfaces’ wettability was assessed using a VINO Contact Angle Goniometer (China, University of Babylon). The samples were positioned correctly on the goniometer’s mechanical stage. Using a needle that was already inserted and at room temperature, On the surface of each specimen, a single drop of distilled water was utilized. The dripping water could be seen by using optics equipment with a high resolution digital camera. Several photos were taken as soon as the drop of distilled water landed on the specimens’ surface. The contact angle was assesed directly following the drop landing and for one minute. We measured the contact angle of each drop twice, once on the left and once on the right of the image. Finally, The two values were averaged to determine the contact angle for each specimen.³⁴

Liner dimensional change test

Because there was a significant effect on the linear dimensional change property of addition silicone materials following immersion in Propolis disinfection (16 mg/ml) for 10 min, the alternative hypothesis was accepted and the null hypothesis was rejected.

There is a chance that the size of the impression could vary as a result of the disinfecting procedure, It can be brought on by a chemical reaction between the setting material and the disinfectant.⁴³

The outcome can be attributable to the ongoing polymerization of the impression material or to the material’s volatile components evaporation.^44,45

This outcome was consistent with research done by Mikaeel and Namuq²⁶ the dental impression materials were employed: polyether,vinyl polysiloxane, and vinyl polyether siloxane. Each of the materials was disinfected using two ways, spraying and immersion, using Dettol, sodium hypochlorite, and Cavex Impresafe. According to the study’s findings, the dimensions of the vinyl polysiloxane material significantly changed after being immersed in sodium hypochlorite for ten min.

Also this study was consistent with Vrbova et al.³¹ study in which scanning electron microscopy, micro computed tomography, and Light microscopy were used to assess the dimensional changes. In comparison to the control group, it was found that the dimensional changes of the disinfection of the elastomeric impression materials in Aseptoprint Liquid and Zeta 7 solution increased significantly.

Details reproduction

The null hypothesis was accepted based on this study’s findings, which demonstrated that 16 mg/ml propolis disinfected impression specimens provided detail reproduction that was comparable to the control specimens score (1).

This outcome was consistent with research done by Mikaeel and Namuq²⁶ the dental impression materials were employed: polyether,vinyl polysiloxane, and vinyl polyether siloxane. Each of the materials was disinfected using two ways, spraying and immersion, using Dettol, sodium hypochlorite, and Cavex Impresafe. the study’s findings demonstrated that the surface detail reproduction was the same prior to and after disinfection and considered as the control group.

Also this study was consistent with Vrbova et al.³¹ study in which scanning electron microscopy, micro computed tomography, and Light microscopy were used to assess the dimensional changes. It was discovered that elastomeric impression materials have very good resistance to the disinfectants. Each of them replicated a 20-μm line.

Compatibility with gypsum products

The null hypothesis was accepted based on this study’s findings, which demonstrated that 16 mg/ml propolis disinfected impression specimens generated casts with comparable compatibility with gypsum as the control specimens score (1).

The hydrophobic and hydrophilic properties of the elastomeric material will dictate how well they interact with the gypsum slurry to create a void-free die.⁴⁶

This outcome was consistent with research done by Vrbova et al.³¹ in which scanning electron microscopy, micro computed tomography, and Light microscopy were used to assess the dimensional changes. It was discovered that elastomeric impression materials have very good resistance to the disinfectants. Each of them, the entire length of a 50-μm line was sharply and clearly imprinted on the gypsum molds.

Wettability

After 10 minutes of immersion in a 16 mg/ml Propolis disinfectant, there was insignificant effect on the Wettability property of additional silicone materials, and the null hypothesis was accepted.

The increasing contact angle determines whether a surface may be wetted by a particular liquid. Higher contact angles increase the chance of air gathering on the surface, which could cause dies or voids in the impression. It is crucial to use a die stone to wet the impression surface since research has linked the amount of bubbles that form in the dies to the water’s contact angle with the impression surface.⁴⁷ Before pouring the cast, the elastomeric (silicone) impressions need to be wetted down, typically with detergent, due to the hydrophobic nature of these impression surfaces.⁴⁸

This outcome was consistent with research done by Anooz and Shorouq²² the addition silicon materials immersed into two disinfectant solutions: propolis (16 mg/ml) for 5,10,15 min and 5.25% NaOCL for 10 min. The addition’s wettability is not significantly affected by a 10-min immersion in 16% propolis.

The study of Kotha et al.⁴⁹ was assessed how several important elastomer properties were affected by autoclave, microwave sterilization and chemical disinfection. Wetability was not significantly affected by any of the sterilizing or disinfection methods.

Surface roughness

After 10 minutes of immersion in a 16 mg/ml of propolis disinfectant, The surface roughness property of the addition silicone impression materials was not significantly affected, the null hypothesis was accepted.

A rough, imperfect impression can be result in a cast that has a rougher surface than the imperfect impression. Therefore, sterilization and disinfection methods shouldn’t have an impact on the impression’s level of roughness. Any prosthesis should be less than 0.2 m in roughness since values greater than this threshold could indicate considerable plaque formation and values below could suggest additional food reduction or unpredicted plaque growth. The rougher surfaces of the prosthesis could easily cause inflammation in the soft tissues that support a prosthesis.⁵⁰

This outcome was consistent with research done by Anooz and Shorouq,²² the addition silicon materials immersed into two disinfectant solutions: propolis (16 mg/ml) for 5,10,15 min and 5.25% NaOCL for 10 min. The addition’s surface roughness is not significantly affected by a 10-min immersion in 16% propolis.

The study of Kotha et al.⁴⁹ was assessed how several important elastomer properties were affected by autoclave, microwave sterilization and chemical disinfection. The outcomes demonstrated that autoclave sterilization and chemical disinfection had no significant effect on surface roughness.