Idomeo Bonetti Filho

Microscopic evaluation of three endodontic files pre- and postinstrumentation

K-type files, Sureflex NiTi files, and FlexoFiles were evaluated morphometrically as they come from the manufacturer, and after being used to instrument root canals 1, 3, and 5 times in maxillary premolars. Evaluation was made using a stereomicroscope at × 40 magnification and photomicrographs. The abnormalities found after instrumentation were submitted for statistical analysis. It was concluded that small-sized stainless-steel instruments should be discarded after one use. On the other hand, #30 stainless-steel K-files could be used up to three times and #30 stainless-steel FlexoFiles up to five times. Sureflex NiTi instruments, even after five times, did not show appreciable abnormalities in shape. It is strongly recommended that small-sized nickel-titanium instruments should be discarded after five uses.

Bacterial leakage evaluation of root canals filled with different endodontic sealers

OBJECTIVE The objective of this study was to evaluate the sealing ability of AH Plus, Epiphany, Acroseal, Endofill, and Polifil after active lateral condensation technique, by using a bacterial test, during 64 days. STUDY DESIGN One hundred bovine incisors were cleaned and shaped; then they were filled with the endodontic sealers and adapted into a microcentrifuge tube. The setup root/microcentrifuge tube was added to glass flasks containing Brain Heart Infusion broth. A culture of Enterococcus faecalis was inserted into the upper chamber of each assembly. Daily leakage was evaluated through the broth turbidity. RESULTS The results were submitted to statistical analysis (Kaplan-Meier method, Kruskal-Wallis and Dunn tests). CONCLUSIONS AH Plus and Endofill had the worst sealing ability when compared with Polifil, which showed the least leakage. Acroseal and Epiphany showed a tendency toward having an intermediate behavior; however, there was no significant difference among Acroseal, Epiphany, and the other sealers.

Ozonized oils: a qualitative and quantitative analysis

Most of the problems of endodontic origin have a bacterial etiological agent. Thus, there is a continued interest in seeking more effective chemical substances that can replace the camphorated paramonochiorophenol or antibiotics as intracanal medicaments. Among the possible substances, ozone has some interesting biological characteristics: bactericidal action, debriding effect, angiogenesis stimulation capacity and high oxidizing power. The purpose of this study was to chemically evaluate the presence of ozone in sunflower, castor, olive and almond oil, as well as in propylene glycol and byproducts of ozonation, such as formaldehyde. These compounds were ozonized, inserted into empty and sterile vials, and analyzed by testing the reaction between ozone and indigo, for determining the presence of ozone, and subjected to the chromotropic acid test for determining the presence of formaldehyde. It was observed complete absence of ozone in all samples tested and presence of formaldehyde. The bactericidal and healing action of ozonized oils could be attributed to products formed by the ozonation of mineral oils, such as formaldehyde, not to the ozone itself.

Cimentos endodônticos - selamento marginal apical imediato e após armazenamento de seis meses

The aim of this study was to verify the apical sealing of root canals obturated with Sealapex, Apexit, Sealer 26, and Ketac Endo cements. A hundred and thirty six dental roots were used for the experiment. After biomechanical preparation and lateral condensation filling, half of the roots were placed in human blood plasma storage medium for 6 months. The remaining samples were immediately placed in methylene blue, under a temporary vacuum, and after one week the amount of dye penetration measured. The stored samples were similarly treated after the 6-month storage period. Statistical analysis of the results revealed that the groups obturated with Sealapex and Sealer 26 showed the smallest amount of apical leakage (p < 0.05). There were significant differences in the amount of dye penetration after 6 months of storage (1.275 mm), when compared to the results found without storage (0.829 mm) (p < 0.05).

Surface characteristics of reciprocating instruments before and after use--a SEM analysis.

The presence of debris, defects and deformations of endodontic reciprocating instruments before and after chemical-mechanical preparation (MCP) was analyzed using scanning electron microscopy (SEM). The following 26 instruments were divided into 2 groups: Waveone (n=13) and Reciproc (n=13) and examined by SEM (150 x magnification) prior to canal preparation at 2 and 4 mm from the tip. The instruments were used in the preparation of mesial root canals of 26 extracted human permanent mandibular molars. The instruments were then washed in ultrasonic bath and subjected to new microscopic analysis of debris and deformation by a score that used the presence or absence of irregular edges, grooves, microcavities and burrs as criteria. After the SEM analysis and with the scores of the examiners, the collected data were subjected to descriptive statistical analysis using the Kruskall-Walis and Mann Whitney test at a 5% significance level. All instruments examined presented debris before and after use. A statistically significant difference was found for defects and deformation between the groups (p<0.05). The presence of defects and deformities was higher in the WaveOne instruments, and Reciproc instruments presented a lower rate.

Safe and easy way to use calcium hydroxide as a temporary dressing.

Calcium hydroxide is used for several clinical applications in endodontic therapy (1, 2). The majority of studies that used this substance, in order to show its biological properties, were done with the pure calcium hydroxide (3-5). The results of these studies are excellent (Fig. l) but the physicochemical properties of pure calcium hydroxide offers some disadvantages. It is radiolucent, permeable to fluids, highly soluble in the periapical region, and without viscosity, adherence, or flow. Moreover, this substance is not easy to apply into the root canal. Thus, in order to obtain a calcium hydroxide product with better clinical properties Leonardo (6), Silva (7), and Bonetti Filho (8) have analyzed, both in vitro and in vivo, 13 different formulations of this substance. The best results (Fig. 2) among these formulations were reached using the following paste: 2.5 g of calcium hydroxide p.a., 0.5 g of zinc oxide p.a., 0.05 g of hydrogenized colophony, and 1.75 ml of polyethylene glycol 400, The polyethylene glycol 400 is a clear, colorless, slightly hygroscopic, viscous vehicle that allows a slower release of hydroxyls and Ca 2÷ ions than aqueous vehicles (9). This paste is packed in sterile anesthesia cartridges (Calen; S. S. White-Artigos Dentfirios Ltda., Rio de Janeiro, Brazil) and dispensed in a special cartridge-type syringe (ML Endodontic Syringe; S. S. WhiteArtigos Dentfirios Ltda.). Using any disposable dental needles, 27-gauge long, this calcium hydroxide paste will flow well and can be easily placed into the root canal.