ABSTRACT
It is of interest to document data on the push - out bond strength of three different root canal treatment sealers such as MTA Fillapex (MTA based), AH plus (Epoxy Resin based) and Apexit plus (Calcium hydroxide based). Forty-five freshly extracted human maxillary central incisors with closed apices were selected randomly. All the teeth were sectioned at cement-enamel junction using a diamond disc before starting the root canal preparation to obtain root length of 12 mm. All teeth were instrumented using ProTaper rotary instruments. 5.25% sodium hypochlorite was used for irrigation between instrumentation followed by 17% EDTA, and final rinse by saline. Obturation procedures were done using the gutta-percha single cone technique. 45 roots were randomly assigned to 3 groups of 15 for obturation with gutta-percha cones and 1 of the 3 sealers (n=15). Group 1 = MTA Fillapex sealer + gutta-percha: Group 2 = AH plus sealer + gutta-percha:Group 3 = Apexit plus sealer + gutta-percha. The roots were sectioned horizontally to its canal into 3 sections: Coronal, Mid-root and Apical-thirds using a precision cutting machine, with a thickness of 3 mm. The specimens were subjected to push-out test using a universal testing machine that carried a plunger. The loading speed was 1mm/min until the dislodgment of the material occurred. The independent t- test was used to compare the mean scores among the study groups. The level of significance was set at 5% for all tests. After the push-out bond strength test, each sample was evaluated under stereomicroscope (40x) to determine the mode of failure and recorded as one of the following categories: adhesive, cohesive or mixed. The observations thus obtained were subjected to statistical analysis using Student - t test. AH Plus showed significantly higher values than MTA Fillapex and Apexit plus (p < 0.05). Amongst the push-out bond strength AH Plus sealer showed significant difference from MTA Fillapex and Apexit plus groups. There was no significant difference between MTA Fillapex and Apexit plus however (p>0.05). Microscopic analysis displayed that the majority of the modes were cohesive failures for AH Plus, adhesive failures for MTA Fillapex and mixed failures for Apexit Plus. . Thus, AH Plus had the highest bond strength and MTA Fillapex had the lowest bond strength to root dentin. Mean push-out bond strength values were ranked as follows; AH Plus >Apexit Plus > MTA Fillapex. Microscopic analysis displayed that the majority of the modes were cohesive failures of AH Plus, adhesive failures for MTA Fillapex and mixed failures for Apexit Plus.
ABSTRACT
BACKGROUND: The aim of this study is to quantitatively evaluate the remineralization potential of three remineralizing systems as follows: fluoride, casein phosphopeptide-amorphous calcium phosphate (CPP-ACP), and CPP-ACP with fluoride, under scanning electron microscope with energy-dispersive X-ray analysis. MATERIALS AND METHODS: In this in vitro study A total of 40 enamel specimens were prepared from the buccal or lingual surfaces of human premolars extracted for orthodontic reason. Specimens were then placed in demineralizing solution for 96 h, to produce artificial caries-like lesion. Calcium and phosphate weight percentage of demineralized specimens was measured. Specimens were divided into four groups as follows: (a) control, (b) CPP-ACP, (c) CPP-ACP with fluoride, and (d) fluoride varnish. Except for the control group, the entire specimens were subjected to remineralization using respective remineralizing agents of their groups. The prepared specimens were assessed for calcium and phosphate weight percentage using scanning electron microscopy-energy dispersive X-ray spectroscopy. One way analysis of variance (ANOVA), followed by Tukey's test, was performed with the help of critical difference (CD) or least significant difference at 5% and 1% level of significance. P ≤ 0.05 was taken to be statistically significant and P < 0.001 as statistically highly significant. RESULTS: The mean weight percentage of calcium and phosphorus of specimens treated with CPP-amorphous calcium phosphate nanocomplexes plus fluoride (ACPF) was significantly higher than other groups. CONCLUSION: All the groups showed statistically significant remineralization. However, because of added benefit of fluoride, CPP-ACPF showed statistically significant amount of remineralization than CPP-ACP.
ABSTRACT
BACKGROUND: Odontogenic Cysts & tumors originate through some aberration from the normal pattern of odontogenesis. Ameloblastoma is one of the most frequent intraosseous odontogenic tumors. However it is no longer appropriate to use the diagnosis of ameloblastoma without specifying the type. Varied-clinical entities of ameloblastoma differ in their biologic behaviour. Odontogenic cysts like dentigerous and radicular cysts are less aggressive in nature than odontogenic tumors. Recently, podoplanin commonly used as a lymphatic endothelial marker in cancers has recently been found to play a possible role in odontogenic tumorigenesis also. Therefore the purpose of this study was to immunohistochemically analyse the expression of podoplanin in ameloblastomas, KCOTs, dentigerous cysts, radicular cysts & dental follicles. METHODS: Paraffin-embedded tissue specimens of 15 Ameloblastomas (7 follicular, 6 unicystic, 2 desmoplastic),10KCOTs, 5 dentigerous cysts, 5 radicular cysts & 5 dental follicles were immunohistochemically examined using antibody against podoplanin. RESULTS: All ameloblastomas displayed podoplanin expression in ameloblast-like cells of the epithelial islands while the stellate-reticulum like cells exhibited no or weak immunostaining. Expression of podoplanin in KCOTs was strongly positive in the cells of the basal and suprabasal layers & odontogenic epithelial nests. Positive immunoreaction for podoplanin was observed in the inflammatory radicular cysts and inflamed dentigerous cyst only and negative or weak expression in the lining epithelium of uninflamed dentigerous cysts and dental follicles. CONCLUSION: Our results suggest that podoplanin can be used as a potential proliferative marker to observe the aggressive behaviour of ameloblastomas and KCOTs.
