Aim: The aim of this study was to evaluate the effects of different solutions on the flexural strength of one methacrylate-based resin and three bis-acryl resin provisional materials using an in vitro model test system. Methods: The specimens (25 × 2 × 2 mm) were prepared from interim materials and stored for 14 days at 37°C in different solutions (coffee, burn, cola) and distilled water (control group). A standard three-point bending test was conducted on the specimens with an Instron universal testing machine at crosshead speed of 0.5 mm/min. Data were analyzed using the one-way analysis of variance and Tukey HSD multiple comprasion tests. Results: The methacry-late-based resin (Takilon) showed the least fracture strength (61.6 - 85.6 MPa). One of the bis-acryl resins (Protemp 4-3M ESPE) showed the highest fracture strength (112 - 128 MPa). Conclusions: All bis-acryl resin composite materials exhibited high fracture strength over the traditional methyl methacrylate resin throughout the 14 day time interval of investigation. The different solutions have not statistically significant effect on the flexure strength values on four temporary materials.
Provisionalization of fixed restorations is an essential part of the treatment before placement of the final restorations. The immediate protective, functional, and stabilizing value of interim restorations are useful for diagnostic purposes where the functional, occlusal, and esthetic parameters are developed to identify an optimum treatment outcome before the completion of definitive procedures [
Provisional materials generally exhibit low fracture strengths, particularly when the patient must use the provisional restoration for an extended period, when the patient have parafunctional habits, or when a long-span prosthesis is planned [
Conventional methacrylate resins are monofunctional, low molecular weight, linear molecules that exhibit decreased strength and rigidity. In addition, if they are not polymerized under pressure, the air bubbles will be trapped and decrease their strength [
In recent years, the composite-based temporary crown and bridge materials have gained popularity among dental practitioners. Besides advantages regarding the handling versus traditional powder-liquid systems, superior mechanical properties might be an explanation for this market trend [
The fracture strength of a provisional crown and bridge material is of particular importance, as this factor might influence the integrity of the provisional restoration during its time in situ (1 - 2 weeks up to several months) [
The flexural strength of interim prostheses is a critical property, particularly in long-span interim prostheses with short height pontics and connectors [
The aim of this study was to investigate the effects of different solutions (cola, coffee, energy drink and distilled water) on the flexural strength of four (one methacrylate-based resin and three bis-acryl resin) provisional restorative materials.
. Materials used in this study
Manufacturer | Composition type | Lot number | |
---|---|---|---|
Protemp 4 | 3M-ESPE,Seefeld,Germany (autopolymerized) | Bis-Acrylic Composite | 9022 |
Structur 2SC | VOCO America, Inc. (autopolymerized) | Bis-Acrylic Composite | 0938052 |
Access Crown | Centrixınc.,Unıtedstates (autopolymerized) | Bis-Acrylic Composite | 6767 |
Takilon | Varpa Ltd. (autopolymerized) | Methylmethacrylate | 879032 |
The mean values of fracture strength of each provisional material was calculated in MPa. Datas were analyzed using the one-way analysis of variance (ANOVA), Tukey HSD multiple comprasion tests, and the significance level was set at α = 0.05.
The mean values and standard deviations of the four provisional materials are shown in
The mechanical stability of temporary crown and bridge materials is important to prevent failure of a temporary restoration directly from the beginning after fabrication and insertion. However, very little information available on this subject in the current literature [
Although laboratory flexural strength values under static loading may not reflect intraoral behaviour, these values are nevertheless helpful in comparing materials under controlled situations and may be a useful predictor of clinical performance [
In the oral environment, it can be assumed that saliva, food components, beverages and interactions among these materials can degrade and age dental restorations [
Akova et al. [
Nejatidanesh et al. [
Balkenhola et al. [
. The mean and standard deviation of the materials in different solutions (MPa)
Materials Solutions | Takilon | Protemp 4 | Structur 2 SC | Access |
---|---|---|---|---|
Distilled water | 69,0a | 122,0c | 119,0c | 110,8bc |
Cola | 68,6a | 128,0c | 105,0bc | 126,0c |
Coffee | 61,6a | 120,0c | 105,0bc | 114,0bc |
Energy drink | 85,6b | 112,0bc | 112,0bc | 118,0bc |
Mean and standard deviations of temporary restorative materials after storage in different solutions for 14 days
then decreased under the influence of thermocycling. Similar tendencies after prolonged water storage are also reported in other investigations for various composites [
Akova et al. [
In the present study, specimens were stored for 14 days in different solutions (coffee was unsweetened, cola was Coca-cola and energy drink was Burn) and distilled water (control group) to partially simulate the oral environment. The results of this study indicated that the different solutions tested did not have a statistically significant effect on the fracture strength of provisional materials, although bis-acryl composite resin materials had the highest flexural strength, and methacrylate resin exhibited the lowest. This result is consistent with those of past studies in which the flexural strength of bis-acryl resins was higher than other conventional interim restorative materials [
Haselton et al. [
Balkenhol et al. [
Balkenhol et al. [
The edge-strength of a polymer-based provisional material could be an important factor to be taken into account in selecting suitable materials for clinical use. These findings show that the monomethacrylate-based provisional restorations would be expected to be more susceptible to mechanical failure and less durable than the dimethacrylate-based provisional restorations when they are exposed to heavy masticatory stresses [
Poonacha et al. [
Gujjari et al. [
Zortuk et al. [
There was no significant difference between methylmethacrylate and composite interim materials in some of the studies [
Direct comparison to other studies [
Starting points for cracks are microscopically small defects in or just beneath the surface of the material created during trimming and polishing [
It should be mentioned that flexural strength is only one of a number of factors influencing the success of an interim prosthesis. A strong material may possess other less desirable characteristics. For example, a restorative material may be difficult to manipulate, have tendency to stain easily, lack polishability, or not be esthetically pleasing [
The clinician must be aware of all attributes of various materials and choose the interim material appropriate for each patient [
Within the limitations of this study, it may be concluded that the flexural strength of provisional restorative materials is not significantly influenced by storage in different solutions. Bis-acryl provisional materials exhibited higher flexural strength than the methacrylate resins.
Thanks for material support to Dt. Beril Balci, 3M ESPE/Turkey. 34th Annual Conference of the European Prosthodontic Association and 1st Conference of the Association of prosthetic Dentistry of Kosova, in September 23-25/2010 Prishtina/Kosova.