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Background: Mineral trioxide aggregate (MTA) becomes a hard mass after setting and making it difficult to remove and can cause significant problems in the retreatment process. The aim of this study was to evaluate the effect of different concentrations of hydrochloric acid (HCl) on MTA dissolution and its effect on dentin. Materials and Methods: In this in vitro study, 45 single-root premolars were selected. Artificially open apex was created in all samples with similar process. The samples were randomly divided into 4 experimental groups of 10, and a control group of 5. Four-millimeter thick apical plugs of Root MTA were placed in all samples in an orthograde manner. HCl was used at concentrations of 3.75%, 7.5%, 15%, and 22.5% (w/v) for the experimental groups and normal saline for the control group. Each sample was exposed to the desired solution for 15 min. Then, MTA retrieval and reaching the working length were attempted with k-file # 30. The times of each sample were recorded. Furthermore, after longitudinal incision of the roots with a disc, the dentin surfaces of canals were examined with a Dino-Lite microscope (×50). Results were analyzed by Shapiro-Wilk test and one-way analysis of variance tests. The level of significance P value was set at 0.05. Results: The lowest average time of reaching working length was observed with group 22.5% that was significantly lower than 15% and 7.5% concentrations (P = 0.005 and P = 0.011). Furthermore, by examining with ×50 of Dino-Lite microscope, no difference was observed on the canal walls. Conclusion: The optimum concentration of HCl was 7.5%. Furthermore, different concentrations of HCl had no significantly different effect on the dentinal canal wall using Dino-Lite microscope with ×50.
RESUMO
Background: In endodontics, glide path creation has been extensively considered a mandatory clinical step to improve the safety and efficiency of rotary nickel-titanium instruments. The high anatomic variations in the mesiobuccal (MB) root of the maxillary molars are observed in the form of canal configuration, number, and position.The aim of this study was to evaluate the negotiability of MB canals in maxillary molars using different pathfiling systems (ProGlider, R-pilot, HyFlex electrical discharge machining [EDM], WaveOne Gold Glider, and C-Pilot). Materials and Methods: This in vitro study included 125 maxillary first molars with closed apex. Before preparation, all teeth were scanned by periapical radiograph for review of the presence of second MB (MB2) canals, without any resorption or calcification, and moderate curve of MB root canal. Subsequently, the access cavity was prepared with a Diamond Fissure Bur. Then, the samples were divided into five groups (ProGlider, R-pilot, HyFlex EDM, WaveOne Gold Glider, and C-Pilot). Certain relevant indices were recorded for analysis, such as the negotiability of the glide path file in the MB canals, file fracture rate, and negotiation speed. The level of significance P value was set at 0.05. Results: In this study, HyFlex EDM was the only path file that could not reach the full working length (WL) in some cases. The highest frequency of file fracture in the MB2 was observed with HyFlex EDM (24%); nevertheless, R-Pilot presented an intermediate fracture rate (16%), and both ProGlider and WaveOne Gold Glider were the safest files (4%) in this regard. However, there were no significant differences between the groups (P = 0.065). The lowest and the highest average time of reaching full WL was observed with WaveOne Gold Glider and HyFlex EDM; nonetheless, there was no significant difference between the four rotary groups. The average number of pecks in HyFlex EDM was significantly higher in comparison to those reported for WaveOne Gold Glider and ProGlider. Conclusion: Path files used for glide path preparation in the MB2 canals of maxillary molars should be flexible with low taper. The use of HyFlex EDM in the MB2 canals is not recommended due to its high taper.
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Surgical ciliated cysts of the maxilla arise from respiratory epithelium that lodges in the maxilla after radical maxillary or sinus surgery. This case report was conducted in 2020 in Mashhad Dental School, Mashhad University of Medical Science, Mashhad, Iran. We present here an unusual case of surgical ciliated cyst of a 73-year-old adult male patient with a history of nasal polyp surgery 40 years ago. Early diagnosis due to CBCT and Clinical examination was a residual cyst or OKC (odontogenic keratocyst). The histopathology result of this lesion surprised us after the excisional biopsy and enucleation. The clinical examinations and radiographs of the jaw lesions may lead the maxillofacial surgeons to misdiagnosis and mistreatment. Therefore, it is obligatory to notice all aspects of these lesions carefully.
RESUMO
BACKGROUND: Increasing the proportion of caries-free children following the WHO's global target has led to more desirable welfare and a higher level of quality of life for children. In the present study, we aimed to evaluate the factors contributing to a caries-free condition in preschool children as a basic action towards the global goals of children's oral health. METHODS: This was a case-control study evaluating the protective factors contributing to dental caries free in 4-6-year-old children in Tehran/Iran in 2017. 500 preschool children and their mothers were selected from 22 randomly selected preschools and were enrolled in the study. The participants were divided into two case (caries-free) and control (with dental caries) groups. The data were collected using two data gathering tools; the child oral examination form and the mother's valid questionnaire. The latter included three domains; socio-demographic factors, behavioral oral health measures, and feeding practices and dietary habits. The criteria for caries detection were cavities in the enamel and dentine. A logistic regression model was applied to identify caries-free protective factors (P < 0.05). RESULTS: Among 230 caries-free and 270 non-caries-free children who participated in the study, boys were more caries-free (P = 0.001). The protective factors against dental caries that were identified in the study were dental check-up as the cause of dental visit, being the first child in the family, the fewer sessions night feeding of the child's, family's house ownership, and parent's university education (P < 0.05). CONCLUSIONS: Dental health can be achieved by considering protective factors like the regular dental check-up and socio-economic factors. Communities are invited to pay close attention to these important protective factors as far as they can increase the proportion of caries-free among preschool children especially in countries with developing oral health care systems.
