Effect of a calcium hydroxide/chlorhexidine paste as intracanal dressing in human primary teeth with necrotic pulp against Porphyromonas gingivalis and Enterococcus faecalis

International Journal of Paediatric Dentistry 2012; 22: 116–124 Background. Intracanal medication is important for endodontic treatment success as it eliminates microorganisms that persist after biomechanical preparation. Aim. To evaluate the effect of two intracanal medications against Porphyromonas gingivalis and Enterococcus faecalis in the root canals of human primary teeth with necrotic pulp with and without furcal/periapical lesion, using quantitative real‐time polymerase chain reaction (qRT‐PCR). Design. Thirty‐two teeth with necrotic pulp were used. Twelve teeth did not present lesion, and 20 teeth presented radiographically visible furca/periapical lesion. Microbiological samples were collected after coronal access and biomechanical preparation. The teeth were medicated with calcium hydroxide pastes prepared with either polyethylene glycol or chlorhexidine. After 30 days, the medication was removed and a third collection was performed. Microbiological samples were processed using qRT‐PCR. Data were analysed by Wilcoxon and Mann–Whitney tests (α = 0.05). Results. There was no significant difference in the microbiota present in the primary teeth with and without furcal/periapical lesion. Biomechanical preparation was effective in reducing the number of microorganisms (P < 0.05). The intracanal medications had similar antibacterial activity. Conclusion. The association of chlorhexidine with calcium hydroxide did not increase the antibacterial activity of the intracanal medication in the treatment of primary teeth with necrotic pulp with and without furcal/periapical lesion.     

Surgical treatment of bisphosphonate-associated osteonecrosis of the jaw: Technical report and follow up of 21 patients

IntroductionBisphosphonates are used to reduce skeletal related events in patients with bone consuming diseases such as osteoporosis and bone metastases. However recently there has been an increased awareness of bisphosphonate-associated necrosis of the jaws (BP-ONJ). Many authors propose conservative management in these cases but invariably the problem is not treated successfully allowing the bone defect to worsen. Recently there has been a move to treat this problem surgically. The aim of this retrospective study was to provide a surgical solution for patients suffering from BP-ONJ.Materials and methodsAll patients presenting with BP-ONJ were treated with bone debridement of the affected area and multilayer wound closure. The considered variables were: gender, age, underlying diagnosis, type of bisphosphonate (BP) used, duration of bisphosphonate use, route of administration, location of the osteonecrosis, clinical symptoms, association with dental treatment and surgical outcome.ResultsNineteen cases of a total of 21 demonstrated no recurrence of osteonecrosis during follow up (Mean 16 months – Range 12–24 months). One patient with a bilateral defect showed a dehiscence on one side and a small fistula on the contralateral side 6 weeks post-operatively and required revision surgery. Another patient developed a fistula after 4 weeks that was treated successfully with antibiotics and curettage. No patients had evidence of exposed bone, bland mucosa nor pain at the surgical site.ConclusionThe technique described can be recommended for patients with BP-ONJ if a conservative treatment fails.     

Degree of conversion of nanofilled and microhybrid composite resins photo-activated by different generations of LEDs

Objective

This study aimed at evaluating the degree of conversion (DC) of four composite resins, being one nanofilled and 3 microhybrid resins, photo-activated with second- and third-generation light-emitting diodes (LEDs).

Material and methods

Filtek^TM Z350 nanofilled composite resins and Amelogen^® Plus, Vit-l-escence^TM and Opallis microhybrid resins were photo-activated with two second-generation LEDs (Radii-cal and Elipar Free Light^TM 2) and one third-generation LED (Ultra-Lume LED 5) by continuous light mode, and a quartz halogen-tungsten bulb (QHT, control). After 24 h of storage, the samples were pulverized into fine powder and 5 mg of each material were mixed with 100 mg of potassium bromide (KBr). After homogenization, they were pressed, which resulted in a pellet that was evaluated using an infrared spectromer (Nexus 470, Thermo Nicolet) equipped with TGS detector using diffuse reflectance (32 scans, resolution of 4 cm^-1) coupled to a computer. The percentage of unreacted carbon-carbon double bonds (% C=C) was determined from the ratio of absorbance intensities of aliphatic C=C (peak at 1637 cm-1) against internal standard before and after curing of the specimen: aromatic C-C (peak at 1610 cm-1).

Results

The ANOVA showed a significant effect on the interaction between the light-curing units (LCUs) and the composite resins (p<0.001). The Tukey''s test showed that the nanofilled resin (Filtek^TM Z350) and Opallis when photo-activated by the halogen lamp (QTH) had the lowest DC compared with the other microhybrid composite resins. The DC of the nanofilled resin (Filtek^TM Z350) was also lower using LEDs. The highest degrees of conversion were obtained using the third-generation LED and one of second-generation LEDs (Elipar Free Light^TM 2).

Conclusions

The nanofilled resin showed the lowest DC, and the Vit-l-escence^TM microhybrid composite resin showed the highest DC. Among the LCUs, it was not possible to establish an order, even though the second-generation LED Radii-cal provided the lowest DC.     

Methylparaben concentration in commercial Brazilian local anesthetics solutions

Objective

To detect the presence and concentration of methylparaben in cartridges of commercial Brazilian local anesthetics.

Material and methods

Twelve commercial brands (4 in glass and 8 in plastic cartridges) of local anesthetic solutions for use in dentistry were purchased from the Brazilian market and analyzed. Different lots of the commercial brands were obtained in different Brazilian cities (Piracicaba, Campinas and São Paulo). Separation was performed using high performance liquid chromatography (HPLC) with UV-Vis detector. The mobile phase used was acetonitrile:water (75:25 - v/v), pH 4.5, adjusted with acetic acid at a flow rate of 1.0 ml.min^-1.

Results

When detected in the solutions, the methylparaben concentration ranged from 0.01% (m/v) to 0.16% (m/v). One glass and all plastic cartridges presented methylparaben.

Conclusion

1. Methylparaben concentration varied among solutions from different manufacturers, and it was not indicated in the drug package inserts; 2. Since the presence of methylparaben in dental anesthetics is not regulated by the Brazilian National Health Surveillance Agency (ANVISA) and this substance could cause allergic reactions, it is important to alert dentists about its possible presence.     

Use of thiazolidinedione and cancer risk in Type 2 diabetes: the Hong Kong diabetes registry

We examined possible anticancer effects of thiazolidinediones (TZDs) in 6074 Chinese with Type 2 diabetes free of cancer at enrolment. During a median follow-up of 4.93 years, 270 patients developed cancer. Use of TZDs was associated with reduced risk of cancer in a dose-response manner in multivariable analysis.