Childhood polybrominated diphenyl ether (PBDE) exposure and executive function in children in the HOME Study

Prenatal exposure to polybrominated diphenyl ethers (PBDEs) have been reported to impair executive function in children, but little is known whether childhood PBDE exposures play a role. Using the Health Outcomes and Measures of the Environment (HOME) Study, a prospective birth cohort in the greater Cincinnati area, we investigated the association between repeated measures of PBDEs during childhood and executive function at 8 years in 208 children and whether effect modification by child sex was present. We used child serum collected at 1, 2, 3, 5, and 8 years to measure PBDEs. The Behavior Rating Inventory of Executive Function was completed by parents to assess executive function at 8 years. We used multiple informant models to examine childhood PBDEs during several exposure windows. Null associations were observed between early childhood PBDEs and executive function. However, we observed significant adverse associations between a 10-fold increase in concurrent concentrations of BDE-28 (β = 4.6, 95% CI 0.5, 8.7) and BDE-153 (β = 4.8, 95% CI 0.8, 8.8) with behavioral regulation. In addition, PBDEs at 8 years were significantly associated with poorer emotional and impulse control. No associations were noted between childhood PBDEs and metacognition or global executive function. However, child sex significantly modified the associations, with significantly poorer executive function among males with higher concurrent BDE-153, and null associations in females. Our study findings suggest that concurrent PBDE exposures during childhood may be associated with poorer executive function, specifically behavior regulation. Males may also be more sensitive to adverse associations of concurrent PBDEs on executive function.     

Small area estimation of under-5 mortality in Bangladesh,Cameroon, Chad,Mozambique, Uganda,and Zambia using spatially misaligned data

Background

The under-5 mortality rate (U5MR) is an important metric of child health and survival. Country-level estimates of U5MR are readily available, but efforts to estimate U5MR subnationally have been limited, in part, due to spatial misalignment of available data sources (e.g., use of different administrative levels, or as a result of historical boundary changes).

Methods

We analyzed all available complete and summary birth history data in surveys and censuses in six countries (Bangladesh, Cameroon, Chad, Mozambique, Uganda, and Zambia) at the finest geographic level available in each data source. We then developed small area estimation models capable of incorporating spatially misaligned data. These small area estimation models were applied to the birth history data in order to estimate trends in U5MR from 1980 to 2015 at the second administrative level in Cameroon, Chad, Mozambique, Uganda, and Zambia and at the third administrative level in Bangladesh.

Results

We found substantial variation in U5MR in all six countries: there was more than a two-fold difference in U5MR between the area with the highest rate and the area with the lowest rate in every country. All areas in all countries experienced declines in U5MR between 1980 and 2015, but the degree varied both within and between countries. In Cameroon, Chad, Mozambique, and Zambia we found areas with U5MRs in 2015 that were higher than in other parts of the same country in 1980. Comparing subnational U5MR to country-level targets for the Millennium Development Goals (MDG), we find that 12.8% of areas in Bangladesh did not meet the country-level target, although the country as whole did. A minority of areas in Chad, Mozambique, Uganda, and Zambia met the country-level MDG targets while these countries as a whole did not.

Conclusions

Subnational estimates of U5MR reveal significant within-country variation. These estimates could be used for identifying high-need areas and positive deviants, tracking trends in geographic inequalities, and evaluating progress towards international development targets such as the Sustainable Development Goals.

     

Antimicrobial efficacy of medicated root canal filling materials

Bacteria remaining within the root canal system are a significant factor in endodontic failures. The aim of this in vitro study was to evaluate the antimicrobial efficacy of commercially available gutta-percha formulations against common endodontic pathogens. Standard, tetracycline, or iodoform (also called medicated gutta-percha; MGP) containing gutta-percha were tested against Actinomyces israelii, A. naeslundii, Enterococcus faecalis, and Fusobacterium nucleatum using the agar diffusion method. Resilon points and tetracycline disks/E-tests were used as negative and positive controls, respectively. Resilon did not display antimicrobial properties. Standard gutta-percha and MGP inhibited F. nucleatum and A. naeslundii, with MGP also inhibiting A. israelii. Tetracycline containing gutta-percha was found to inhibit growth from all four bacterial species tested. The results of this study suggest that the use of tetracycline containing gutta-percha as an obturation material may be useful as a complement to the cleaning and disinfection phase of root canal procedures.     

Fabrication of a craniofacial implant surgical and treatment planning guide

A procedure is described to fabricate a surgical guide to assist in the placement of craniofacial implants for prosthetic auricular rehabilitation. An impression is made of the defect, and a wax pattern of the missing ear is completed and evaluated on the patient. The definitive wax prosthesis is processed in acrylic resin. An occlusal maxillary splint is also fabricated. The occlusal splint and the acrylic resin ear are joined together using an extraoral acrylic resin bar. The resulting surgical guide provides proper orientation of the acrylic resin ear while remaining securely attached to the maxillary arch. This surgical guide can also be utilized for pretreatment radiographic examination.     

Anorganic porous bovine-derived bone mineral (Bio-Oss) and ePTFE membrane in the treatment of peri-implantitis in cynomolgus monkeys

The purpose of the present study was to evaluate the effect of anorganic porous bovine-derived bone mineral (Bio-Oss) and expanded polytetrafluoroethylene (ePTFE) membrane in the treatment of peri-implantitis. A total of 64 implants with a titanium plasma-sprayed (TPS) surface was inserted in eight cynomolgus monkeys (Macaca fascicularis). After a 3-month healing period with plaque control, experimental peri-implantitis characterized by a bone loss of 4-6 mm was induced during a period of 9-18 months. Surgical treatment involving Bio-Oss+membrane, Bio-Oss, membrane, or a conventional flap procedure (control) only was carried out. The animals were sacrificed six months after treatment. Evaluation by clinical parameters, radiography including quantitative digital subtraction radiography, histology, and stereology demonstrated healthy peri-implant tissue irrespective of the applied surgical procedure. However, the amount of re-osseointegration and the total amount of bone (Bio-Oss and regenerated bone) were significantly higher in defects treated with membrane-covered Bio-Oss as compared with the other three treatment procedures. A mean bone-to-implant contact of 36% was obtained within defects treated with membrane-covered Bio-Oss. The corresponding values for the three other treatment procedures were 13-23%. The Bio-Oss particles were in general highly integrated within the regenerated bone, but the particles in the occlusal part of the defects were entirely surrounded by connective tissue irrespective of membrane coverage. The present study demonstrates that surgical treatment involving Bio-Oss covered by an ePTFE membrane is a useful treatment modality of experimental peri-implantitis around implants with a TPS surface in cynomolgus monkeys. However, the treatment outcome is not as encouraging as seen with membrane-covered autogenous bone graft particles documented in a study with same experimental design.     

EFFECT OF ACID ETCHING OF GLASS IONOMER CEMENT SURFACE ON THE MICROLEAKAGE OF SANDWICH RESTORATIONS

The purposes of this study were to evaluate the sealing ability of different glass ionomer cements (GICs) used for sandwich restorations and to assess the effect of acid etching of GIC on microleakage at GIC-resin composite interface. Forty cavities were prepared on the proximal surfaces of 20 permanent human premolars (2 cavities per tooth), assigned to 4 groups (n=10) and restored as follows: Group CIE – conventional GIC (CI) was applied onto the axial and cervical cavity walls, allowed setting for 5 min and acid etched (E) along the cavity margins with 35% phosphoric acid for 15 s, washed for 30 s and water was blotted; the adhesive system was applied and light cured for 10 s, completing the restoration with composite resin light cured for 40 s; Group CIN – same as Group CIE, except for acid etching of the CI surface; Group RME – same as CIE, but using a resin modified GIC (RMGIC); Group RMN – same as Group RME, except for acid etching of the RMGIC surface. Specimens were soaked in 1% methylene blue dye solution at 24°C for 24 h, rinsed under running water for 1 h, bisected longitudinally and dye penetration was measured following the ISO/TS 11405-2003 standard. Results were statistically analyzed by Kruskal-Wallis and chi-square tests (α=0.05). Dye penetration scores were as follow: CIE – 2.5; CIN – 2.5; RME – 0.9; and RMN – 0.6. The results suggest that phosphoric acid etching of GIC prior to the placement of composite resin does not improve the sealing ability of sandwich restorations. The RMGIC was more effective in preventing dye penetration at the GIC-resin composite- dentin interfaces than CI.     

Effect of sodium hypochlorite on primary dentin--a scanning electron microscopy (SEM) evaluation

OBJECTIVE: The aim of this study was to evaluate the alterations of etched deciduous dentin when submitted to different time and concentrations of sodium hypochlorite (NaOCl), using scanning electron microscopy (SEM). MATERIAL AND METHODS: Forty deciduous anterior teeth were selected, cleaned and ground until expose a flat dentin area on the buccal surface. The specimens were randomly distributed into eight groups (n=5), according to dentin surface treatment (35% phosphoric acid etching for 7s--AE and/or NaOCl application), NaOCl solution concentration (5% or 10%), and time of application (0, 30, 60, and 120 s), as follows: G1: control (without AE and NaOCl); G2: only AE; G3, G4, and G5: AE+5% NaOCl for 30, 60, and 120 s, respectively; G6, G7, and G8: AE+10% NaOCl for 30, 60, and 120 s, respectively. All specimens were prepared for SEM analysis and the photomicrographs (three for each specimen) were classified according to a score as follow: 0: presence of smear layer (SL); 1: absence of SL+non-altered collagen fibrils; 2: absence of SL+collagen fibrils slightly altered; 3: absence of SL+collagen fibrils severely altered; and 4: absence of SL and absence of collagen fibrils. Data were submitted to Kruskal-Wallis and Mann-Whitney tests (p<0.05). RESULTS: All groups treated with NaOCl solution were significant different from G1 and G2, and showed alterations on the collagen fibrils network. Collagen complete removal was only observed when a 5% NaOCl solution was applied for 120 s and 10% NaOCl solution for 30, 60, and 120 s. CONCLUSIONS: The NaOCl action produced significant changes in the etched deciduous dentin. The higher NaOCl concentration, the lower the time required to completely removing the collagen fibrils network in deciduous dentin.