The influence of restorative material and glass fiber posts on fracture strength of endodontically treated premolars after extensive structure loss

OBJECTIVE

The aim of this in vitro study was to investigate the fracture strength and cuspal deflection of endodontically treated premolars restored using different composite resins along with or without fiber post application.

MATERIALS AND METHOD

Eighty intact premolars were randomly divided into eight groups (n = 10); CO group: intact teeth (control), OPR group: mesio-occlusal-distal-palatal (MODP) preparation (OPR) + endodontic treatment (ET), TC group: MODP preparation + ET + Tetric N-Ceram, TB group: MODP preparation + ET + Tetric EvoCeram Bulk Fill, SO group: MODP preparation + ET + SonicFill 2, TC-P group: MODP preparation + ET + Hahnenkratt glass fiber post + Tetric N-Ceram, TB-P group: MODP preparation + ET + Hahnenkratt glass fiber + Tetric EvoCeram Bulk Fill, and SO-P Group: MODP preparation + ET + Hahnenkratt glass fiber post + SonicFill 2. After thermocycling, specimens were subjected to a compressive load until fracture. Data were analyzed using analysis of variance and Tukey tests (P < 0.05).

RESULTS

The mean fracture strength of groups which received post treatment showed similar fracture strength values [TC-P (931.6 ± 97.9), TB-P (882.0 ± 59.7), SO-P (862.0 ± 143.0) (P > 0.05)] and was significantly higher than OPR (530.6 ± 41.7), TC (841.2 ± 93.1), TB (774.5 ± 101.8), and SO (735.0 ± 178.01) groups (P < 0.05). No significant difference was detected among groups considering cuspal deflection (P > 0.05). The fiber post insertion resulted in more unfavorable fractures.

CONCLUSION

Endodontically treated teeth restored with fiber post and bulk-fill or conventional composite resins demonstrated fracture strength values similar to intact teeth.

First Report of Chickpea chlorotic stunt virus Infecting Legume Crops in Tunisia

During a survey of legume crops in the northeast and northwest regions of Tunisia in April 2010, plants showing yellowing, reddening, and stunting symptoms were observed. A total of 281 symptomatic samples were collected: 142 plants from 10 chickpea (Cicer arietinum L.) fields, 84 plants from six faba bean (Vicia faba L.) fields, and 55 plants from six pea (Pisum sativum L.) fields. All samples were tested by the tissue-blot immunoassay procedure with the following monoclonal antibodies (MAbs): a broad-spectrum legume-luteovirus MAb (5G4), Faba bean necrotic yellows virus (FBNYV; genus Nanovirus, family Nanovirudae) (3-2E9; provided by J. Vetten, BBA, Braunschweig, Germany), Beet western yellows virus (BWYV; genus Polerovirus, family Luteoviridae) (A5977; Agdia, Elkhart, IN), Bean leafroll virus (BLRV; genus Luteovirus, family Luteoviridae) (4B10), Soybean dwarf virus (SbDV; genus Luteovirus, family Luteoviridae) (ATCC PVAS-650; American Type Culture Collection ATCC, Rockville, MD,), and a mixture of three MAbs (5-2B8, -3D5, and -5B8) to a Syrian isolate of Chickpea chlorotic stunt virus (CpCSV) (1). Serological tests showed that CpCSV was detected in 121 samples (43.06%) (62 chickpea, 57 faba bean, and 2 pea), followed by FBNYV (detected in three faba bean and three pea), BWYV (detected in three chickpea and one faba bean), and BLRV (detected in one pea sample). FBNYV, BLRV, and BWYV have been previously detected in faba bean and chickpea in Tunisia (4), but to our knowledge, this is the first report of CpCSV affecting legumes in Tunisia, which was found in seven chickpea, seven faba bean, and two pea fields. CpCSV has been reported to naturally infect legume crops such as chickpea, lentil, field pea, and faba bean as well as some leguminous weeds and a few wild non-legume plants species in many countries in West Asia and North Africa and causes economic losses on chickpea in Eritrea, Ethiopia, and Syria (1-3). Serological results of CpCSV was confirmed in four (two pea, one faba bean, and one chickpea) samples by reverse transcription (RT)-PCR using CpCSV specific primers (F:5'-TAGGCGTACTGTTCAGCGGG-3' and R:5'-TCCTTTGTCCATTCGAGGTGA-3') (3), which produced an amplicon of expected size (413 bp). No amplification was observed from healthy plant extracts. Sequence analysis revealed that the four Tunisian isolates (TuV 258-201 collected from faba bean [GenBank Accession No. HQ199310], TuC 215-201 collected from chickpea [HQ199307], and TuP 163-201 [HQ199308] and TuP 166-201 collected from pea [HQ199309]) were most similar to each other with a high sequence identity (99%) and clustered with isolates of CpCSV from Syria (GenBank Accession No. EU541270), Egypt (EU541269), and Morocco (EU541267), to which they were most closely related (98%). The Tunisian isolates also showed high sequence identity (96%) in the coat protein region with Ethiopian (GenBank Accession No. EU541257) and Sudanese (EU541263) isolates. However, all isolates are distinct from BWYV, BLRV, and SbDV (less than 70% sequence identity). Since CpCSV is transmitted by aphids only, additional studies are needed to identify the host range of the virus and the efficient aphid vectors to better understand the epidemiology of this virus under Tunisian conditions References: (1) A. D. Abraham et al. Arch.Virol. 154:791; 2009. (2) N. Y. Asaad et al. J. Phytopathol. 157:756, 2009. (3) S. G. Kumari et al. Phytopathol. Mediterr. 47:42, 2008. (4) A. Najar et al. Phytopathol. Mediterr. 39:423, 2000.

Validity of the rapid strip assay test for detecting HBsAg in patients admitted to hospital in Uganda

Commercially available rapid strip assays (RSAs) for hepatitis B surface antigen (HBsAg) are used for most routine clinical testing in sub-Saharan Africa. This study evaluated the validity of RSA and a more sophisticated enzyme immunoassay (EIA) with confirmation by nucleic acid testing (NAT) in hospitalized patients in Uganda. Sera from 380 consecutive patients collected and tested for HBsAg and anti-HIV in Kampala, Uganda by RSA were sent frozen to Dallas for EIA including HBsAg, total anti-hepatitis B core, hepatitis B e antigen, and anti-HIV. NAT was performed on all HBsAg-positives and on a random sample of 102 patients that were HBsAg-negative by both assays. Overall, 31 (8%) were HBsAg positive by RSA while 50 (13%) were HBsAg-positive by EIA; 26 were concordant between the two assays. Of 55 HBsAg-positive patients, nearly all showed detectable serum hepatitis B virus (HBV) DNA by bDNA (46) or PCR (4) assay. The 26 patients who were HBsAg positive by both EIA and RSA had significantly higher median serum HBV DNA levels than the 24 patients who were HBsAg positive by EIA alone. An additional 12/102 (12%) HBsAg negative patients had very low serum HBV DNA levels by NAT. Several differences in expected results of serologic testing were observed in this large series of African patients. RSA HBsAg testing is less sensitive than EIA; even EIA failed to detect all HBV DNA positive sera. A more complex testing protocol than RSA alone will be needed in Africa to improve patient care.

Poor performance of hepatitis C antibody tests in hospital patients in Uganda

Most hepatitis C testing in Uganda is performed using commercial rapid strip assays (RSA) to detect antibodies to hepatitis C virus (anti-HCV), rather than enzyme immunoassays (EIA). The prevalence of hepatitis C antibodies in a Ugandan hospital population was determined using both methods to test their accuracy using nucleic acid testing (NAT) as a reference. Sera from 380 consecutive hospitalized Ugandan patients were tested for anti-HCV using an RSA in Uganda, with subsequent automated third-generation EIA testing in the United States, followed by NAT. Recombinant immunoblot assays (RIBA) were used as a supplementary test to detect anti-HCV epitopes. Overall, anti-HCV was detected in 48/380 (13%) by one or both antibody tests. Anti-HCV was detected in 19 (5.0%) patients by RSA and in 33 (8.7%) patients by EIA; only four patients were anti-HCV positive by both methods. Fourteen of the 48 anti-HCV positive patients had detectable serum HCV RNA, 7 each by bDNA assay or by PCR. RSA detected only 7 of 14 HCV RNA positive sera. Of 29 RNA negative but anti-HCV positive patients tested by RIBA, only two were anti-HCV positive; 27 were anti-HCV negative or indeterminate. Anti-HCV testing by RSA and/or EIA was neither sensitive nor specific for detection of ongoing HCV infection in hospitalized Ugandan patients. Our findings underscore the importance of confirmatory nucleic acid testing, which, despite its increased cost, appears essential to manage African patients with HCV.

First Report of Beet mosaic virus Infecting Chickpea (Cicer arietinum) in Tunisia

Chickpea plants with severe yellowing and tip wilting were observed in the Cap-Bon Region of Tunisia in 2006. The viral-like symptoms resulted in yield loss of approximately 25% in some fields. A total of 110 symptomatic chickpea plants was collected from nine chickpea fields and tested at the Virology Laboratory of ICARDA, Syria for eight legume viruses using tissue-blot immunoassay (TBIA) (3). Polyclonal antisera produced at the ICARDA Virology Laboratory were used to test for Chickpea chlorotic dwarf virus (genus Mastrevirus, family Geminiviridae), Broad bean stain virus (genus Comovirus, family Secoviridae), Broad bean mottle virus (genus Bromovirus, family Bromoviridae), and Bean yellow mosaic virus and Pea seed borne mosaic virus (genus Potyvirus, family Potyviridae). Antiserum to Beet mosaic virus (BtMV; genus Potyvirus, family Potyviridae) (AS-0143) was provided by the German Collection of Microorganisms and Cell Cultures (DSMZ, Braunschweig, Germany). In addition, three monoclonal antibodies (MAb) were used to detect Faba bean necrotic yellows virus (FBNYV; genus Nanovirus, family Nanoviridae) (MAb 3-2E9) (1), potyviruses (PVAS-769 [MAb PTY 3 Potyvirus Group] American Type Culture Collection, Manassas, VA), and luteoviruses (MAb B-2-5G4) (2). Twenty-two of the plants tested positive with MAb PTY 3 and BtMV antisera, 56 samples reacted with MAb B-2-5G4, and eight plants with the FBNYV MAb, whereas 24 plants tested negative with all antisera. Because reactions with the BtMV antiserum were unexpected, detection of BtMV was confirmed by reverse transcription-(RT)-PCR assays using BtMV-specific primers (LN26 and LN27) (4), which produced an amplicon of expected size (1,050 bp) from all plants that reacted with BtMV antiserum but not from plants that were serologically negative. Leaf tissue from a BtMV-infected plant was ground in 0.01 M potassium phosphate buffer, pH 7.2 (1:20, wt/vol), mixed with 0.5% celite, and used for mechanical inoculation of chickpea seedlings (cv. Beja 4). In addition, adults of three legume aphid species (Aphis craccivora, A. fabae, and Acyrthosiphon pisum) were starved for 1 h before feeding on BtMV-infected chickpea leaves for an acquisition access period of 5 min. Fifteen aphids of each species were placed on each chickpea plant, allowed to feed for 24 h, and then sprayed with an insecticide. Tip wilting symptoms appeared on plants 15 to 20 days after mechanical and aphid inoculations but not on plants used as negative control treatments (inoculated mechanically with healthy leaf tissue or with aphids that had fed on noninfected chickpea plants). Use of BtMV antiserum for TBIA analysis of inoculated plants revealed systemic BtMV infections in 35 of 92 plants inoculated mechanically and 15 of 75 plants inoculated with viruliferous A. fabae only. To our knowledge, this is the first record of BtMV infecting chickpea in Tunisia. References: (1) A. Franz et al. Ann. Appl. Biol. 128:255, 1996. (2) L. Katul. Characterization by serology and molecular biology of bean leaf roll virus and faba bean necrotic yellows virus. Ph.D. thesis. University of Gottingen, Germany, 1992. (3) K. M. Makkouk and A. Comeau. Eur. J. Plant Pathol. 100:71, 1994. (4) L. G. Nemchinov et al. Arch. Virol. 149:1201, 2004.

First Report of Faba bean necrotic yellows virus Affecting Legume Crops in Azerbaijan

A total of 482 chickpea (Cicer arietinum L.), 182 lentil (Lens culinaris Medik.), 12 vetch (Vicia sativa L.), 5 field pea (Pisum sativum L.), and 3 faba bean (Vicia faba L.) samples were collected from plants with symptoms suggestive of a viral infection (leaf rolling, yellowing, and stunting) from the major legume-production areas of Azerbaijan in the 2007 and 2008 growing seasons. All samples were tested by the tissue-blot immunoassay (3) at the Virology Laboratory of ICARDA, Syria using 11 specific legume virus antisera including a monoclonal antibody (2-5H9) (1) for Faba bean necrotic yellows virus (FBNYV). Laboratory tests showed that FBNYV was detected in 73, 61, 11, 3, and 2 samples of chickpea, lentil, vetch, field pea, and faba bean, respectively. Total DNA was extracted from six FBNYV-positive samples (two chickpea, two lentil, and two vetch) and tested by PCR with the following four primer sets (FBNYV, Milk vetch dwarf virus [MDV], Subterranean clover stunt virus [SCSV], and nanovirus DNA-R primers [F103 and R101]) (2). All six Azeri samples as well as the reference nanovirus isolates (SCSV-Australia, MDV-Japan, and FBNYV-Syria) generated amplicons of the expected size (~770 bp) using the nanovirus DNA-R primers (F103 & R101). In addition, Azeri samples and FBNYV-Syria yielded a PCR amplicon of the expected size (666 bp) with the FBNYV primer pair. The MDV- and SCSV-specific primers did not generate amplicons with these six samples. Sequence analysis of the FBNYV amplicons from two isolates (AzL 282-07 from lentil [GenBank Accession No. GQ351600] and AzV 277-07 from vetch [GenBank Accession No. GQ371215]) showed that they were 99% identical with each other. Comparing the sequence of AzL 282-07 with that of other nanoviruses revealed identities of 97% (FBNYV-Spain; DQ830990), 96% (FBNYV-Iran; AM493900), 92% (FBNYV-Syria; Y11408), 92% (FBNYV-Egypt; AJ132183), 78% (MDV; AB044387) and 69% (SCSV-Australia; U16734). FBNYV has been reported to infect food legumes in many countries in West Asia and North Africa and cause economic losses on faba bean in Egypt, Jordan, and Syria. To our knowledge, this is the first record of FBNYV infecting legume crops in Azerbaijan. References: (1) A. Franz et al. Ann. Appl. Biol. 128:255, 1996. (2) S. G. Kumari et al. Phytopathol. Mediterr. 47:42, 2008. (3) K. M. Makkouk and A. Comeau. Eur. J. Plant Pathol. 100:71, 1994.

The Influence of One-step Polishing Systems on the Surface Roughness and Microhardness of Nanocomposites

One-step polishing systems exhibited similar or better surface roughness values when compared to multi-step polishing systems. In all groups, mylar-strip created surfaces showed lower microhardness values than polished surfaces. Different polishing procedures did not effect the microhardness of nanocomposites. One-step polishing systems may be a good choice for polishing nanocomposites, resulting in reduced chair time.

Treatment of hepatitis B with lamivudine and tenofovir in HIV/HBV-coinfected patients: factors associated with response

As therapy for human immunodeficiency virus (HIV) infection evolves, optimizing hepatitis B virus (HBV) treatment and identifying factors that impact its response in the HIV/HBV-coinfected population is critical. We identified retrospectively 45 HBV/HIV-coinfected patients with detectable HBV DNA by the Bayer VERSANT HBV 3.0 bDNA assay (limit of quantification 2000 copies/mL) at baseline and/or year 1 of therapy. Patients were divided into three groups based on the active HBV agent in their antiretroviral regimen: group 1 (n = 15) received lamivudine; group 2 (n = 10), lamivudine plus tenofovir and group 3 (n = 20), lamivudine followed by lamivudine plus tenofovir. HBV genotypes and resistance profiles were determined by the Bayer Trugene HBV 1.0 assay. More patients in group 2 achieved HBV DNA suppression below 2000 copies/mL (80%), loss of HBe antigen (HBeAg) (40%) and loss of HBeAg and gain of anti-HBe (20%) than did patients in group 1 or 3. More patients with HBV genotype A, achieved HBV DNA suppression <2000 copies/mL than did patients with non-A genotypes [74% (26/35) vs 20% (2/10)], respectively (P = 0.003). Risk for virological nonresponse was significant in those with non-A genotypes [odds ratio (OR) 11.1; 95% CI: 2.0-50], previous HIV therapy (OR 6.5; 95% CI: 1.2-35) and <90% compliance (OR 3.7; 95% CI: 0.99-14.3). Simultaneous therapy with lamivudine/tenofovir suppresses HBV DNA more effectively than lamivudine or tenofovir added to lamivudine. More patients infected with HBV genotype A responded than the non-A patients, regardless of therapeutic regimen, compliance or prior HIV therapy.

First Report of Chickpea Chlorotic Dwarf Virus Infecting Spring Chickpea in Syria

During May 2003, a high incidence of symptoms suggestive of virus infection in spring chickpea were observed in many fields in Al-Ghab Valley, Syria, the ICARDA farm (near Aleppo, Syria), as well as in other locations in northern Syria, including the Idleb governorate. Symptoms observed were yellowing, stunting, and necrosis. A total of 1,345 chickpea samples with these symptoms (331 from Al-Ghab Valley, 269 from the ICARDA farm, and 745 from the Idleb governorate) were collected and tested for the presence of five viruses with tissue-blot immunoassay (TBIA) (4) at the Virology Laboratory of ICARDA, using the following antisera: monoclonal antibodies for Faba bean necrotic yellows virus (FBNYV, genus Nanovirus) (1); Bean leafroll virus (BLRV, family Luteoviridae) (4B10) (3); Beet western yellows virus (BWYV, genus Polerovirus, family Luteoviridae [ATCC PVAS-647, American Type Culture Collection, Manassas, VA]); and Soybean dwarf virus (SbDV, family Luteoviridae, [ATCC PVAS-650]) and polyclonal antibodies for Chickpea chlorotic dwarf virus (CpCDV, genus Mastrevirus, family Geminiviridae, provided by H. J. Vetten, BBA, Braunschweig, Germany). The most common virus present was BWYV (detected in 54.1% of samples tested), followed by CpCDV (19.2%), BLRV (10.2%), and FBNYV (5.5%). SbDV was not detected in any of the samples tested. Using immunosorbent electron microscopy, infected chickpea samples revealed low numbers of geminivirus-like particles after 15 min of incubation on CpCDV antiserum-coated grids. When CpCDV was purified from infected chickpea plants, the virus coat protein was 32 kDa with sodium dodecyl sulfate-polyacrylamide gel electrophoresis typical of CpCDV coat protein (2) and reacted strongly with CpCDV antiserum in western blots. The CpCDV vector in Syria was found to be Orosius albicinctus Distant, and is thought to be similar to Orosius orientalis (Matsumura), the reported vector of CpCDV (2). FBNYV, BWYV, and BLRV infection of chickpea have been previously reported from Syria, but to our knowledge, this is the first report of CpCDV infecting chickpea in Syria. References: (1) A. Franz et al. Ann. Appl. Biol. 128:255, 1996. (2) N. M. Horn et al. Ann. Appl. Biol. 122:467, 1993. (3) L. Katul. Characterization by serology and molecular biology of bean leaf roll virus and faba bean necrotic yellows virus. Ph.D. thesis. University of Gottingen, Germany, 1992. (4) K. M. Makkouk and A. Comeau. Eur. J. Plant Pathol. 100:71, 1994.

The effect of flowable resin composites as gingival increments on the microleakage of posterior resin composites

Microleakage has been a major concern in restorative dentistry. The curing contraction of composites still presents a problem with controlling microleakage and postoperative sensitivity. This study investigated the effect of flowable materials on gingival microleakage of microhybrid and packable resin composite restorations. Ninety Class II cavities with cervical margins 1 mm below the CEJ were prepared in 45 extracted human premolars. The teeth were randomly divided into three groups (n=15). In each group, one side of each tooth was restored incrementally with respective composites-SureFil, Filtek P60 and Tetric Ceram; whereas, on the other side, flowable materials-Dyract Flow, Filtek Flow or Tetric Flow-were placed respectively as a 1-mm thick gingival increment before the resin composite restoration. The restored teeth were stored for one week in distilled water at 37 degrees C, thermocycled between 5 degrees C and 55 degrees C and immersed in 0.5% basic fuchsin for 24 hours. Dye penetration was evaluated using a stereomicroscope at 10x magnification. The data were analyzed statistically by Kruskal-Wallis analysis of variance and Mann-Whitney U-tests. The effect of flowable increments on reducing the gingival microleakage was found to be statistically significant for all restorative materials tested (p<0.05).

Fluoride release and uptake characteristics of aesthetic restorative materials

The aims of this study were firstly to investigate the fluoride-releasing characteristics of two composite resins (Tetric and Valux Plus), two polyacid-modified resin composites (Compoglass and Dyract), and conventional glass-ionomer cement (Ceramfil beta). The second aim was to assess the fluoride uptake and subsequent release from the same range of materials. Fifteen discs (6 mm diameter and 1.5 mm height) were prepared for each material. Each disc was immersed in 4 ML of deionized water within a plastic vial. The release of fluoride was measured daily at 1, 2, 3, 4, 5, 15, 30 and 60 days. After daily fluoride release was measured for 60 days, samples were refluoridated in 1000-ppm sodium fluoride (NaF) solutions (pH 6.6) for 10 min and fluoride release was measured daily for a total of 5 days. The release of fluoride from aesthetic restorative materials was measured by using specific fluoride electrode and an ionanalyser. Results were statistically analysed by two-way repeated measure ANOVA and Duncan's multiple range test. The results revealed that all fluoride-containing materials (Ceramfil beta, Compoglass, Dyract, Tetric) released fluoride initially and the release was greatest at the first day. At any time during the test period Ceramfil beta released the most and Valux Plus did not release any detectable fluoride (P < 0.01). Sample exposures to 1000 ppm NaF solution increased the 24-h fluoride release from all fluoride-containing materials. This difference lasted only 24-48 h after exposure. Ceramfil beta had a tendency to recharge not seen with the other materials (P < 0.05).

Microleakage of two polyacid-modified resin composites under different conditioning methods in primary teeth

This study evaluated the effect of different conditioning methods on micro-leakage in primary teeth. Fifty-one cervical cavities were prepared on the twenty-six extracted primary molars and divided randomly into five groups. In Group I and IV phosphoric acid, in group 11 non-rinse conditioner (NRC) was applied. In group III and V no pretreatment was used. Groups I-III were restored with Prime & Bond NT and Dyract AP and Group IV-V restored with Syntac SC and Compoglass F. The restored teeth were stored for 24 hours in distilled water at 37 degrees C, immersed in 0.5 percent basic fuchsin for 24 hours. Dye penetration was determined using a stereomicroscope. The results revealed that although enamel microleakage was not affected by the conditioning method used in both restorative materials, pretreating the cavity with phosphoric acid had a positive effect on reducing the dentin microleakage compared with conditioning by NRC.