Accuracy of three electronic apex locators in the presence of different irrigating solutions

The present study compared the accuracy of three electronic apex locators (EALs) - Elements Diagnostic?, Root ZX? and Apex DSP? - in the presence of different irrigating solutions (0.9% saline solution and 1% sodium hypochlorite). The electronic measurements were carried out by three examiners, using twenty extracted human permanent maxillary central incisors. A size 10 K file was introduced into the root canals until reaching the 0.0 mark, and was subsequently retracted to the 1.0 mark. The gold standard (GS) measurement was obtained by combining visual and radiographic methods, and was set 1 mm short of the apical foramen. Electronic length values closer to the GS (± 0.5 mm) were considered as accurate measures. Intraclass correlation coefficients (ICCs) were used to verify inter-examiner agreement. The comparison among the EALs was performed using the McNemar and Kruskal-Wallis tests (p < 0.05). The ICCs were generally high, ranging from 0.8859 to 0.9657. Similar results were observed for the percentage of electronic measurements closer to the GS obtained with the Elements Diagnostic? and the Root ZX? EALs (p > 0.05), independent of the irrigating solutions used. The measurements taken with these two EALs were more accurate than those taken with Apex DSP?, regardless of the irrigating solution used (p < 0.05). It was concluded that Elements Diagnostic? and Root ZX? apex locators are able to locate the cementum-dentine junction more precisely than Apex DSP?. The presence of irrigating solutions does not interfere with the performance of the EALs.     

A possible mechanism of low molecular weight protein tyrosine phosphatase (LMW-PTP) activity modulation by glutathione action during human osteoblast differentiation

Objective

Low molecular weight protein tyrosine phosphatases (LMW-PTPs) are a family of enzymes strongly involved in the regulation of cell growth and differentiation. Since there is no information concerning the relationship between osteoblastic differentiation and LMW-PTP expression/activity, we investigated its involvement during human osteoblast-like cells (hFOB 1.19) differentiation. It is known that LMW-PTP is regulated by an elegant redox mechanism, so we also observed how the osteoblastic differentiation affected the reduced glutathione levels.

Design

hFOB 1.19 cells were cultured in DMEM/F12 up to 35 days. The osteoblast phenotype acquisition was monitored by measuring alkaline phosphatase activity and mineralized nodule formation by Von Kossa staining. LMW-PTP activity and expression were measured using the p-nitrophenylphosphate as substrate and Western blotting respectively. Crystal violet assay determined the cell number in each experimental point. Glutathione level was determined by both HPLC and DNTB assays.

Results

LMW-PTP modulation was coincident with the osteoblastic differentiation biomarkers, such as alkaline phosphatase activity and presence of nodules of mineralization in vitro. Likewise LMW-PTP, the reduced glutathione-dependent microenvironment was modulated during osteoblastic differentiation. During this process, LMW-PTP expression/activity, as well as alkaline phosphatase and glutathione increased progressively up to the 21st day (p < 0.001) of culturing, decreasing thereafter.

Conclusions

Our results clearly suggest that LMW-PTP expression/activity was rigorously modulated during osteoblastic differentiation, possibly in response to the redox status of the cells, since it seems to depend on suitable levels of reduced glutathione. In this way, we pointed out LMW-PTP as an important signaling molecule in osteoblast biology and bone formation.     

Intermittent cigarette smoke inhalation may affect bone volume around titanium implants in rats

BACKGROUND: A negative influence of smoking on implant outcomes has been reported. This animal study investigated the influence of cigarette smoke on osseointegration and newly formed bone within implant threads. METHODS: Male Wistar rats were included in the study. After anesthesia, the tibiae surface was exposed and a screw-shaped titanium implant (4.0 mm in length; 2.2 mm in diameter) was placed bilaterally. The animals were randomly assigned to group 1, control, or group 2, intermittent cigarette smoke inhalation. The animals were sacrificed after 60 days and undecalcified sections obtained. The degree of bone-to-implant contact (BIC) and the bone area (BA) within the implant threads were measured in the cortical (zone A) and cancellous bone (zone B) areas. RESULTS: A slight difference in the BIC was noted between the groups, but this was not statistically significant either in zone A or in zone B (Mann-Whitney test, P > 0.05). In contrast, the BA close to the implant significantly decreased in both zones for group 2 (84.73% +/- 4.77 versus 79.85% +/- 6.17, zone A in groups 1 and 2, respectively, and 32.01% +/- 6.62 versus 20.71% +/- 8.57, zone B in groups 1 and 2, respectively, P < 0.05). CONCLUSION: Within the limits of the present study, intermittent cigarette smoke inhalation may result in a poor bone quality around titanium implants inserted in rats.     

Isotypic antibody response to plaque anaerobes in periodontal disease

BACKGROUND: It has been suggested that locally produced immunoglobulin (Ig)A could be more protective than IgG and that there could be a relationship between crevicular fluid-specific IgA levels and the onset of periodontal disease. This study was designed to investigate this hypothesis regarding specific immune responses towards 4 plaque anaerobes in gingival crevicular fluid and saliva from patients with periodontopathies and controls. METHODS: Gingival crevicular fluid (GCF) and whole saliva were collected from 35 adults with periodontitis and 24 periodontally healthy adults (controls). Antigens were extracted from Actinomyces actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, and Fusobacterium nucleatum and used to set up specific enzyme-linked immunosorbent assay (ELISA) tests to assess IgA and IgG levels to these microorganisms in the fluids collected. RESULTS: The crevicular fluid of periodontitis patients contained significantly higher levels of IgG to the 4 microorganisms tested than that of controls (P < 10(-6) for all comparisons). IgA levels to the 4 bacteria were statistically significantly much higher in control crevicular fluid (P < 10(-7) for all comparisons). Controls also had statistically significantly higher levels of specific salivary IgA than patients (P < 0.02 for all comparisons). CONCLUSIONS: These data support the potentially protective role of specific IgA directed to oral microorganisms involved in the onset and development of periodontal disease.     

In vivo influence of residual moisture on microtensile bond strengths of one-bottle adhesives

Purpose: This study evaluated the microtensile bond strengths of three dentin adhesives applied on clinically moist dentin or on dentin that was dried with air for 5 seconds. The null hypothesis to test was that the level of residual moisture does not influence bond strengths when restorations are placed in vivo.
Materials and Methods: Twenty-four premolars scheduled to be extracted for orthodontic reasons from patients between the ages of 15 and 23 years were restored with one of the following adhesive systems followed by a mini hybrid composite resin: Excite (Ivoclar/Vivadent), an ethanol-based dentin adhesive; Prime & Bond NT (Dentsply/Caulk), an acetone-based dentin adhesive; and Single Bond (3M ESPE), an ethanol and water-based dentin adhesive. After extraction, the specimens were sectioned with a slow-speed diamond saw in two perpendicular directions to obtain sticks with a cross-section of 0.7 ± 0.2 mm². The specimens were attached to a Geraldeli device and fractured using a universal testing machine at a crosshead speed of 1 mm per minute.
Results: For each dentin adhesive, there were no statistical differences between means for dry dentin versus moist dentin. Single Bond and Prime & Bond NT ranked in the same statistical subset regardless of the moisture condition of the substrate. Both Excite, dry, and Excite, moist, resulted in statistically lower bond strengths than Single Bond, moist, but similar to those of Single Bond, dry, Prime & Bond NT, moist, and Prime & Bond NT, dry.
CLINICAL SIGNIFICANCE
In this study, the level of residual moisture did not influence microtensile bond strengths. Clinically, the degree of moisture left on the dentin surface upon rinsing off the etching gel may not be as relevant as previously reported in laboratory studies.     

Allergic contact dermatitis associated with the use of facemask on a patient with a history of atopy

Allergic contact dermatitis (ACD) is a skin inflammation caused by an allergic reaction after contact with small external substances capable of being absorbed by the skin. There are several studies describing allergic reactions to intraoral orthodontic appliances, especially those containing nickel. Allergic reactions due to extraoral appliances are not as frequent, and there are relatively few studies about them. Extraoral eactions are attributed to metallic, elastic, or textile parts of the extraoral appliances. This article's purpose was to report the appearance of an allergic contact dermatitis reaction in a 9-year, 2-month-old female patient, with a history of atopic dermatitis, after an orthodontic facemask was fitted. Rapid maxillary expansion was also performed with a Hyrax appliance while a facemask was used. Early diagnosis of this pathology is essential in order to achieve a total regression of the reaction. Orthodontists should be aware that ACD can be caused by facemasks in predisposed patients.     

Changes in pituitary and prolactin cells of Wistar rats after two dental fillings with bisphenolic resins

Bisphenol-A (BPA) is used to manufacture dental materials such as sealants, fillings and cements. There is evidence of its estrogenic effects on recipients after the placement of dental sealants. Pituitary and especially prolactin (PRL) cells are targets for estrogens.

Objectives

The aim of this research was to determine if BPA eluted from dental resins can alter the proliferation of pituitary cells and PRL cells in the short, medium and long term in a case-control assay.

Methods

Two dental fillings were inserted in the lower incisors of Wistar rats divided into groups sacrificed after one, three, five and seven months. Immunocytochemical treatment was carried out in order to determine proliferating cell nuclear antigen (PCNA) positive cells, PRL-positive cells, PRL- and PCNA-positive cells.

Results

A significant increase of PCNA-positive cells after one (p < 0.05), three (p < 0.01) and five months (p < 0.01) was recorded. PRL-positive cells showed no statistically significant difference between intervened animals and controls. PRL- and PCNA-positive cells manifested a significant increase after five months (p < 0.05). A significant decrease in proliferating cells was observed after seven months (p < 0.05) for PCNA-positive cells and (p < 0.01) for PRL- and PCNA-positive cells.

Conclusion

Low quantities of BPA eluted during mastication can affect immunocytochemical patterns of pituitary cells, increasing cellular proliferation in the short, medium and long term although PRL cell population remained unaffected after dental fillings.     

Evaluation of apical cavity preparation with a new type of ultrasonic diamond tip

This study evaluated the time, occurrence of fracture, and quality of apical cavity preparation with three different ultrasonic diamond tips: Satelec, Trinity, and a new type, CVD (chemical vapor deposition), using scanning electron microscopy (SEM) analysis. Thirty human single-rooted premolars were selected, submitted to apicectomy, and prepared with ultrasonic tips; impressions were then obtained. The presence of fractures was evaluated on the impressions, and the quality of preparation was evaluated by SEM analysis of teeth and scoring by two examiners. The group prepared with the CVD tips exhibited the shorter preparation time and did not present fractures. There was no statistically significant difference in the quality of preparation for the three tips. The three brands of ultrasonic tips produced adequate grinding without altering the morphology of the apical foramen.