Degradation Of Restorative Materials Research Articles

The effect of different organic solvents on the degradation of restorative materials.

Objective:To evaluate the solubility of three restorative materials exposed to the different endodontic solvents.Materials and Methods:The organic solvents eucalyptus oil, xylol, chloroform, and orange oil, with distilled water as the control group was utilized. The restorative materials light-cured resin (Filtek Z250/3M ESPE), light-cured-resin-reinforced glass ionomer (Riva Light Cure LC/Southern Dental Industries SDI]) and resin-modified glass ionomer (Vitremer/3M ESPE) were analyzed. A total of 50 disks containing specimens (2 mm × 8 mm Ø) were prepared for each of the three classes of restorative materials, which were divided into 10 groups (n = 5) for immersion in eucalyptus oil, xylol, chloroform, orange oil or distilled water for periods of either 2 min or 10 min. The means of restorative material disintegration in solvents were obtained by the difference between the original preimmersion weight and the postimmersion weight in a digital analytical scale. Data were statistically analyzed by two-way analysis of variance while the difference between the materials was analyzed by Student-Newman-Keuls test. The significance level set at 0.05.Results:Vitremer showed the highest solubility, followed by Riva LC, and these were statistically different from eucalyptus oil, xylol, chloroform, and distilled water (P < 0.05). Regarding the immersion time in solvents, there were no significant differences between the two tested periods (P > 0.05).Conclusions:The solvents minimally degraded the composite resin, although they did influence the degradation of both resin-modified glass ionomer resin and resin reinforced with glass ionomer.

In vitro long-term degradation of aesthetic restorative materials in food-simulating media

Objective. The aim of this study was to evaluate the effect of long-term food-simulating media storage on degradation of restorative materials through roughness measurements. Materials and methods: Sixty cylindrical specimens of each material (Filtek Z250, Esthet X, Filtek Flow, Dyract AP and Vitremer) were prepared, stored for 24 h, and polished. The surface roughness analysis was conducted using Surfcorder (SE1700) roughness-measuring instrument. Three traces were recorded on each specimen at three different locations. The specimens were randomly distributed into five groups (n = 12) according to the storage media: (water, ethanol, Coca-Cola®, citric acid and lactic acid). Roughness measurements were recorded after 1 week, 1, 3 and 6 months. The storage solutions were weekly changed. Data were submitted to ANOVA and Tukey test (p < 0.05). Results. There was no significant increase on roughness means for Filtek Z250, Filtek Flow and Vitremer over time, regardless the storage media. Significant increase on surface roughness was observed for Esthet X after 1 month of storage in Coca-Cola® and after 3 months of storage in citric acid and for Dyract AP after 6 months in water. There were no significant differences on surface roughness between resin composites and compomer. Resin-modified glass ionomer showed a significantly higher surface roughness mean than the other materials. Conclusions. Food-simulating media affects the surface roughness of the materials. Biodegradation is material-, solution- and time-dependent.

Chemical Degradation of Restorative Materials

The chemical environment is an important aspect of the oral environment that could have an appreciable influence on restorative materials. The effects of chemical media on surface roughness, Vickers hardness and weight loss of a ceramic material, a hybrid ceramic resin, an ormocer and a posterior composite were investigated. The specimens were made for each material and were stored in artificial saliva at 37oC for 24 h. The weight of the specimens were recorded and then randomly divided into two groups and stored in the following chemicals for 2 weeks at 37oC: 0.02 N citric acid and 0.02 N lactic acid. After conditioning, the specimens were weighed again and subjected to Vickers hardness and surface roughness tests. The specimens were also examined in the scanning electron microscopy (SEM). All results were analyzed statistically. After a 2 week storage period, there was a significant weight loss in P60 TM stored in citric acid and Admira TM stored in lactic acid. Vickers hardness values of all materials except Finesse were increased significantly (p<0.05).

Fatigue and wear of dental materials

Fatigue and wear are two of the many basic physical processes which contribute to the degradation of restorative materials. The mechanisms of these are discussed in the context of general engineering and the dental environment. More work is required to define the processes involved in intraoral degradation of materials.

Effect of dental plaque formation on the degradation of restorative materials—pH changes under the dental plaque formed on the different restorations

Effect of dental plaque formation on the degradation of restorative materials—pH changes under the dental plaque formed on the different restorations