Bacterial microleakage of Root MTA, Pro Root MTA and prtland material in preparing of furca perforation

Forca perforation is one of the unexpected and unwanted accidents while root canal procedures which affects the long term prognosis of the therapy. Different material such as ProRoot MTA and MTA has been suggested to repair these perforations; however, the high price of these material has been troublesome for the patients and made the researchers to look for more suitable substitutions.Considering that Root MTA in comparison with other material is more accessible and suitable in price, the present study has been conducted to compare the bacterial microleakage of these three material [Root MTA, ProRoot MTA, Portland cement] to repair forca perforations. In this experimental invitro study, 60 extracted molars were divided into three experimental groups of Root MTA, ProRoot MTA and Portland cement [18 teeth in each group]. There were also two groups of positive and negative in the study [3 teeth in each]. Following access cavity preparation, cleaning and shaping was done. The crowns and the roots of the teeth were cut and the roots were filled. Then a perforation with the diameter of 1mm in the central part of the pulp chamber of each teeth was made. After repairing the perforations with the three material under study, the teeth were exposed to stafillococus epidermis bacteria and the degree of microleakage in each teeth was evaluated at the end of the first and the fifth week with the use of Cochrane, exact fischer and Chi-squre tests. The microleakage in ProRoot MTA group was: 8.27, in Root MTA group was:8.27 and in the group of Portland cement was:3.33. according to statistical tests there were no significant difference amonge these three groups from the point of microleakage and the time of its occurrence. Considering the lack of any significant difference among the three groups under this study, provided that other characteristics of Root MTA and Portland cement are proven, these two are capable to act as substitutions for ProRoot MTA

[Relationship between Interleukin 4 and 12 and chronic periapical lesion size]

Chronic dental periapical lesions resulted from chronic inflammatory response to the periapical tissues. Since T-helper [CD4+Y] cells are the prominent cells in these lesions, so the aim of this study was to determine the correlation between the concentration of IL-4 and IL- 12 [most important cytokines for differentiation of T helper 2 and T helper 1 cells, respectively], and the diameter of chronic periapical lesions. Thirty-eight chronic periapical lesions were collected which 18 periapical lesions had diameter of >/= 5 millimeter [case group] and 20 periapical lesions had the diameter <5 millimeter [control group]. Tissue samples were cultured for 72 hours, then ELISA [Enzyme linked immuno-sorbent Assay] was used for determining the concentration of IL-4 and IL- 12 in supernatant fluids. Mann-whitney U and Spearman correlation tests were used to analyze the data. IL-4 and IL- 12 were found in all of samples. There was no significant difference between case and control groups regarding the concentration of IL-4, IL- 12 and IL-4/IL- 12. The only significant correlation was between IL-4 and IL-6 concentration without any regard to the diameter of lesions [P<0.001] [Spearman correlation coefficient=0.593]. It is concluded that in chronic periapical lesions, probably T helper 1 and T helper 2 cells participate in active phases of inflammation and tissue damage equally. This could be resulted from mixed population of bacteria in these lesions

[Fluoride retention in saliva following toothbrushing with two Iranian fluoride dentifrices, Nasim and Crend in comparison with sample dentifrices]

The presence of fluoride in oral fluids, is necessary for prevention of dental caries. The aim of this study was to determine the extent of fluoride retention in saliva after brushing with two Iranian fluoridated toothpastes, Nasim and Crend in comparison with MacLeans and Crest. Ten adults used a nonfluoride dentifrice for 10 days before the experiment and between different stages of the experiment. The dentifrices included Nasim and MacLeans [with sodium monofluorophosphate] and Crend and Crest [with sodium fluoride]. In each procedure, participants brushed their teeth with 1.5 gr of the dentifrices under trial for 1 minute. Saliva samples were collected at baseline, 1, 30, 60; 120 minutes after tooth brushing and fluoride ion were measured by potentiometry technique. The data were analyzed by Repeated Measurements, Paired t, One Way ANOVA and Tukey tests. All dentifrices under this trial, had the highest fluoride concentration in saliva 1 minute after brushing [P<0.005] and after that time fluoride concentration decreased gradually. Crest toothpaste in comparison with Crend had higher fluoride retention in the 60 and 120 minutes [60 minutes: [0.9824 +/- 0.0988, 0.5173 +/- 0.770] [P<0.005]; 120 minutes: [0.8103 +/- 0.0615, 0.3651 +/- 0.0580] [P<0.008]]. The Crest dentifrice showed the most fluoride retention in saliva, MacLeans and Nasim dentifrices had similar values of fluoride retention while the Crend dentifrice showed the least values of fluoride retention

[Bleaching effect of sodium perborate mixed with four different concentrations of H[2]O[2] on artificial stained pulpless teeth]

The use of various techniques of teeth bleaching as a conservative and low-cost procedure is common and generally accepted today. The purpose of this study was to evaluate the bleaching effect of sodium perborate mixed with four different concentrations of H[2]O[2] on artificial stained pulpless teeth. In this experimental single-blind study, 64 extracted human premolars were stained in vitro with human RBCs mixed with iron sulfide II, and randomly divided into 4 test groups and one control group. The bleaching agents of sodium perborate mixed with 7.5%, 15% and 30% H[2]O[2] and distilled water were placed in pulp chambers of the teeth. The bleaching effects of each group were evaluated using a digital camera and L*a*b system. Adobe Photoshop 7.0 software was used to measure the color changes through the procedure. Delta E was used to describe color changes numerically. The data were analyzed by Kolmogorov Smirnov, ANOVA and SPSS Ver. 9.0 software. The results revealed that sodium perborate mixed with H[2]O[2] 30% significantly had more whitening effect than the other groups [P=0.001], but there was no significant difference among the bleaching effect of the other groups. The most bleaching effect was gained by H[2]O[2] 30% .On the other hand due to no significant difference between 15% and 7.5% of H[2]O[2] with water, using sodium perborate mixed with water is one of the safest methods in teeth bleaching

Evaluation of distortion and fracture of flexmaster and profile files during root canal preparation conducted by endo It control instrument in human molar

Although rotary instruments have been used for cleaning and shaping procedures during root canal preparation; nevertheless, the most effective technique regarding the use of these instruments has not been determined yet. Therefore, this study was carried out to evaluate the distortion and fracture of Flexmaster and Profile files during root canal preparation. This process was carried out by Endo IT Control instruments on human molar teeth. A total of 60 human molar teeth with 10 -30 curved roots were randomly divided in two groups. Flexmaster and Profile files were used in the first and second groups using crown-down technique. The instrumentation speed, time and torque were controlled using Endo IT Control according to manufacturer's instructions. The fracture and distortion of files were evaluated in both groups. There was not any instrument fracture in the study, but 3 distortion cases were observed [2 in Profile group and 1 in Flexmaster one]. The difference between distortions in two groups was not statistically significant. Likewise, no relationship was found between distortion and repeated use of instruments in the sample. There was not any difference regarding fracture between the two groups. However, distortion of files in Profile group was more than Flexmaster group when Endo IT Control instrument was used