ABSTRACT
Statement of Problem: Ameloblastomas are locally aggressive tumors with which the researchers have been mostly concerned to understand their biological behavior. Overexpression of minichromosome maintenance 3 [MCM3, a recently introduced marker] has been reported in different cancers. There is no study about MCM3 expression in ameloblastoma
Purpose: This study aims at the evaluation of MCM3, Ki-67 and p27 in ameloblastoma
Methods and Material: In this analytical study, 18 ameloblastomas were selected. Clinicohistopathological data were recorded and immuohistochemical staining was done on the newly cut sections for Ki-67 antigen, p27 kip1 and MCM3. The immunostained cells were counted on 10 HPF [Labeling Index] and then classified into negative [LI50] levels. Statistical analysis was performed in SPSS, version 13, using ordinal regression and Freidman tests. P value less than 0.05 was considered significant
Results: Among the lesions, 5 [27.8%] and 13 [72.2%] were negative and weak for Ki-67, respectively. Also, 5 [27.8%], 11[61.1%] and 2 [11.1%] lesions were negative, weak and moderate, respectively for p27. Ki-67 and p27 staining were seen more frequently in the ameloblast layer and stellate reticulum, respectively. None of the samples was stained by MCM3. There were significant differences among Ki-67, p27 and MCM3 expression in ameloblastomas but no differences were found between sex, age and tumor size and expression of these markers
Conclusion: Most of the ameloblastomas expressed low levels of Ki-67 and p27 [72.2% and 61.1%, respectively]. It could not be concluded exactly how these tumors will behave in the future, because low expression of p27 is in favor of cell proliferation [in contrast to low expression of Ki-67]. To find out how biological behavior of these tumors will be in the future, other markers should be evaluated and all the patients should be followed up. Regarding the negative expression of MCM3 in all lesions, it seems that MCM3 is not involved in the pathogenesis of ameloblastoma
ABSTRACT
One of the most important reasons of endodontic failure is the persistence of microbial factors in the root canal system. Therefore, three-dimensional cleaning of the root canal space is very important to eliminate or reduce the irritant factors and microorganisms. To evaluate the effectiveness of Mtwo R and ProTaper Retreatment files as compared with Mtwo and ProTaper files in retreatment of the gutta-percha filled root canals. In this in-vitro study, fifty extracted single root premolars with approximately straight and similar root lengths were selected. Primary preparation of the root canals was performed by ProTaper rotary system and all of the roots were filled by lateral condensation technique. Then, the teeth were randomly divided into five groups, and each group was retreated with one of the ProTaper, ProTaper Retreatment, Mtwo, Mtwo R systems and hedstrom hand files. Following the longitudinal splitting of the roots with diamond discs and evaluation of amount of the gutta-perchal sealer on the root canal walls with stereomicroscope. Obtained results were analyzed with kruskal-wallis and Mann- Whitney u tests. Complete removal of gutta-perchal sealer did not occur with any of the investigated systems .There is significant statistical differences between test groups at the apical and middle thirds of canals [P=0.849, P=0.315 respectively]. In Hedstrom group, significantly less filling material was observed in the coronal third of canals. Regardindg the duration of retreatment, all of the rotary systems were significantly more rapid than hand files. Rotary files that were specifically designed for retreatment, were significantly more rapid than universal ProTaper. Despite this fact that neither of used techniques in this study were able to remove the filling material completely, but regarding to higher speed and probability of less fracture of the files specifically designed for retreatment [Mtwo R and ProTaper Retreatment] as compared with universal rotary files [Mtwo R and ProTaper], we suggested that these files can be appropriate choice for root canal retreatment
Subject(s)
Dental Pulp Cavity , In Vitro Techniques , Treatment OutcomeABSTRACT
Introduction: root canal preparation is one of the most important stages of endodontic treatment. It seems that rotary NiTi files are efficient instruments in root canal preparation
Objective: this in vitro study was designed to assess the degree of canal transportation, resulting from instrumentation by a new rotary system [protaper] and to compare it with rotary profile 0.04 taper series 29 system and hand K- flexofiles in a Step- back manner
Materials and Methods: thirty six mesiobuccal canals of extracted human mandibular molars were instrumented in three groups by each of these methods respectively. Rotary systems were used in a crown- down manner according to the manufacture's instruction, and stainless steel K- flexofiles were used in a conventional step- back method. Pre- and postoperative X- rays were taken, projected and degree of canal curvature was determined according to the schneider method. The difference of pre- and postoperative canal curvature was evaluated with ANOVA and student tests
Results: the results of statistical analysis indicated that the degree of canal transportion in protaper group was statistically less than that in K- flexofile group that this difference was statistically significant[P<0.0001]. There was no significant difference between two rotary groups[P<0.05]
Conclusion: on basis of the results obtained from this study, profile 0.04 taper and protaper systems were significantly less likely to change the canal curvature in comparison to stainless K- flexofiles, lie, the former methods compared to the latter one have better capabilities in maintaining the original shape of root canal