Effect of a cross-linking antioxidant agent on the bond strength of adhesive resin to irradiated dentin.

It has been shown that irradiation can cause structural changes in dentin that may reduce the bond strength of adhesives to dentin. Applying cross-linking or antioxidant agents may help reverse this detrimental effect and improve adhesion to dentin. This in vitro study aimed to evaluate the effects of epigallocatechin-3-gallate (EGCG) pretreatment and the time of adhesive bonding (24 hours vs 1 month) on the shear bond strength (SBS) of All-Bond Universal (ABU) to irradiated dentin using etch-and-rinse (ER) and self-etching (SE) modes. Flat dentin surfaces prepared from 96 extracted intact human molars were divided into 8 groups (n = 12) and bonded with ABU. In the control (CO) groups (CO/ER and CO/SE), bonding was performed on nonirradiated dentin; in the irradiated (IR) groups (IR/ER and IR/SE), bonding was performed on irradiated dentin; in the irradiated pretreated groups (IR/EGCG/ER and IR/EGCG/SE), irradiated dentin received a 0.1% EGCG pretreatment before bonding; and in the irradiated delayed bonding (DL) groups (IR/DL/ER and IR/DL/SE), bonding on irradiated dentin was performed 1 month after completion of radiotherapy. The irradiation protocol consisted of a total dose of 60 Gy with 2-Gy exposure applied 5 days per week for a period of 6 weeks. After bonding procedures were completed, the specimens were stored in 100% humidity at 37°C for 24 hours and then the SBS was tested in a universal testing machine. Data were analyzed using 1-way analysis of variance and Tukey tests. There was a statistically significant difference among the 8 groups (P < 0.001). Irradiation diminished the SBS in the IR/ER and IR/SE groups compared with their controls (P < 0.001). Pretreatment with EGCG significantly increased the SBS in the IR/EGCG/ER group only (P < 0.001). The difference between the IR/ER and IR/DL/ER groups was not statistically significant, and the difference between the IR/SE and IR/DL/SE groups was marginally significant (P = 0.056). Pretreatment with EGCG after acid etching restored the SBS of ABU to irradiated dentin, resulting in an adhesive performance equivalent to that observed with nonirradiated dentin. A 1-month delay between irradiation and bonding did not improve the SBS.

Effect of silver antibacterial agents on bond strength of fiber posts to root dentin

Abstract This study was conducted to evaluate whether antibacterial pretreatment irrigation with silver nanoparticles (SNPs) and silver diamine fluoride (SDF) has any effect on bond strength of fiber posts cemented with three types of resin cements in root canal space. Fifty-four endodontically treated maxillary central incisor roots were prepared for fiber post (FRC Postec Plus NO.3, Ivoclar Vivadent) cementation and divided into nine groups in terms of three cement types and two pretreatments with silver antibacterial agents. The cements were as follows: an etch-and-rinse cement (ER, Excite DSC/Variolink N), a self-etch cement (SE, ED Primer/Panavia F2.0), and a self-adhesive cement (SA, Panavia SA Luting Plus). For each cement, the control group was with no treatment and two experimental groups were with SNPs and SDF treatments that were used after acid-etching for ER cement and after EDTA treatment for SE and SA cements. After fiber post cementation, each bonded root was horizontally sectioned into 1-mm thickness microslices to create two slices for each root region (apical, middle and coronal) and underwent push-out bond strength (PBS) test. Data in MPa were analyzed with two-way ANOVA and Tukey test (p=0.05). The interaction of the pretreatment type and cement type was significant (p<0.001). SNPs and SDF significantly increased PBS with ER cement (p≤0.04). This positive effect was also marginally significant for SDF with SE cement (p=0.049). For SA cement, SNPs showed a significant positive effect, but SDF had a significant adverse effect on PBS (p<0.001). The effect of pretreatment with silver antibacterial agents prior to adhesive cementation of fiber posts depends on the resin cement used. Contrary to SNPs with beneficial or no significant effect on bonding for all cements, SDF exhibited a deleterious effect with self-adhesive cement.

Resumo Este estudo foi conduzido para avaliar se a irrigação de pré-tratamento antibacteriano com nanopartículas de prata (SNPs) e fluoreto de diamina de prata (SDF) tem algum efeito na resistência de união de pinos de fibra cimentados com três tipos de cimentos resinosos no espaço do canal radicular. Cinquenta e quatro raízes de incisivos centrais superiores tratadas endodonticamente foram preparadas para cimentação de pino de fibra (FRC Postec Plus NO.3, Ivoclar Vivadent) e divididas em nove grupos em termos de três tipos de cimento e dois pré-tratamentos com agentes antibacterianos de prata. Os cimentos foram os seguintes: um cimento etch-and-rinse (ER, Excite DSC / Variolink N), um cimento autocondicionante (SE, ED Primer / Panavia F2.0) e um cimento autoadesivo (SA, Panavia SA Luting Plus). Para cada cimento, o grupo controle foi sem tratamento e dois grupos experimentais foram com SNPs e SDF tratamentos que foram usados após o condicionamento ácido para o cimento ER e após o tratamento com EDTA para os cimentos SE e SA. Após a cimentação do pilar de fibra, cada raiz ligada foi seccionada horizontalmente em microclimas de 1 mm de espessura para criar duas fatias para cada região da raiz (apical, média e coronal) e submetida ao teste de resistência de união por push-out (PBS). Os dados em MPa foram analisados ​​com ANOVA de dois fatores e teste de Tukey (p = 0,05). A interação do tipo de pré-tratamento e tipo de cimento foi significativa (p<0,001). SNPs e SDF aumentaram significativamente o PBS com cimento ER (p≤0,04). Este efeito positivo também foi marginalmente significativo para SDF com cimento SE (p = 0,049). Para o cimento SA, os SNPs mostraram um efeito positivo significativo, mas o SDF teve um efeito adverso significativo no PBS (p <0,001). O efeito do pré-tratamento com agentes antibacterianos de prata antes da cimentação adesiva dos pinos de fibra depende do cimento resinoso utilizado. Ao contrário dos SNPs com efeito benéfico ou nenhum efeito significativo na adesão para todos os cimentos, o SDF exibiu um efeito deletério com o cimento autoadesivo.

Differential expression of drug resistance genes in CD146 positive dental pulp derived stem cells and CD146 negative fibroblasts.

INTRODUCTION: The stem cell portion of the dental pulp derived cultures (DPSCs) showed a higher resistance to cytotoxic effect of restorative dental materials compared to pulpal fibroblasts (DPFs). Here, we aimed to compare the expression of some drug resistant genes between these cells. METHODS AND MATERIALS: To separate DPSCs from DPFs, we used magnetic cell sorting technique based on CD146 expression. To assess the stem cell properties, the positive and negative portions underwent colony forming assays and were induced to be differentiated into the adipocytes, osteoblasts, hepatocytes, and neural cells. Cell surface antigen panels were checked using immune fluorescence and flow-cytometry techniques. The mRNA expression of 14 ABC transporters including ABCA2, ABCB1, ABCB11, ABCC1, ABCC2, ABCC3, ABCC4, ABCC5-2, ABCC5-4,ABCC5-13, ABCC6, ABCC10, ABCC11, and ABCG2 genes was assessed, using quantitative RT-PCR technique. RESULTS: Only the CD146 positive portion could be differentiated into the desired fates, and they formed higher colonies (16.7 ± 3.32 vs. 1.7 ± 1.67, p < .001). The cell surface antigen panels were the same, except for CD146 and STRO-1 markers which were expressed only in the positive portion. Among the ABC transporter genes studied, the positive portion showed a higher expression (approximately two-fold) of ABCA2, ABCC5-13, and ABCC5-2 genes. CONCLUSION: Dental pulp stem cells which can be separated from dental pulp fibroblasts based on CD146 expression, express higher levels of some drug resistance genes which probably accounts for their features of more resistance to cytotoxic effects of some dental materials. This needs to be more validated in future.

Comparison of shear bond strength of orthodontic brackets bonded with a universal adhesive using different etching methods

ABSTRACT Objective: The aim of this study was to compare the effects of three enamel etching modes - laser-etch, self-etch and acid-etch (5, 10 and 15 s) - on bracket bonding, using a universal adhesive. Methods: Eighty-four maxillary premolars were randomly divided into seven groups (n=12) based on the etching method and the adhesive used for bracket bonding. After water storage and thermocycling, shear bond strength was measured, and adhesive remnant index scores on debonded enamel were determined. Results: There were significant differences between the seven groups regarding bond strength values (p< 0.001). The highest values were observed in universal adhesive with laser etching group, while Transbond XT with acid or laser etching, and universal adhesive used in self-etch mode demonstrated the lowest bond strength. The universal adhesive with the three different etching times presented with statistically similar results, all showing an improvement in bond strength, compared with Scotchbond universal (SBU)/SE. Conclusions: The universal adhesive evaluated in the present study demonstrated statistically similar bond strengths to conventional orthodontic adhesive in self-etch mode. The bond strength can be improved by adding an initial acid etching or laser conditioning step, although enamel damage was observed in some cases.

RESUMO Objetivo: o objetivo desse estudo foi comparar os efeitos de três métodos de condicionamento do esmalte - condicionamento a laser, autocondicionamento e condicionamento ácido (5, 10 e 15 segundos) - sobre a colagem de braquetes com um adesivo universal. Métodos: oitenta e quatro pré-molares superiores foram divididos aleatoriamente em sete grupos (n=12) de acordo com o método de condicionamento e o adesivo utilizado para a colagem dos braquetes. Após armazenamento em água e termociclagem, a força de colagem foi medida e o índice de adesivo remanescente no esmalte após a descolagem foi determinado. Resultados: houve diferenças significativas entre os sete grupos com relação aos valores de força de colagem (p< 0,001). Os valores mais altos foram observados no grupo com adesivo universal e condicionamento a laser, enquanto o Transbond XP condicionado com ácido ou laser, e o adesivo universal autocondicionante demonstraram as menores forças de colagem. O adesivo universal apresentou resultados estatisticamente semelhantes para os três diferentes tempos de condicionamento ácido, todos mostrando um aumento na força de colagem, em comparação ao Scotchbond Universal. Conclusões: o adesivo universal avaliado no presente estudo demonstrou força de colagem estatisticamente semelhante aos adesivos ortodônticos convencionais do tipo autocondicionante. A força de colagem pode ser aumentada acrescentando-se uma etapa inicial de condicionamento ácido ou com laser, embora danos ao esmalte tenham sido observados em alguns casos.

Sealing of silorane-based composite in laser-prepared primary teeth: effect of acid etching.

PURPOSE: The purpose of this study was to evaluate the influence of prior etching on the sealing of silorane composite restorations in Class V cavity preparations prepared with an Er,Cr:YSGG laser compared to bur preparation in primary teeth. METHODS: Standard Class V cavity preparations were prepared on the buccal surfaces of 56 extracted primary canines and randomly divided into four groups of 14 teeth each, according to laser or bur preparation and the use of prior acid etching in the preparation. All cavity preparations were restored with silorane adhesive and silorane composite. After water storage and thermocycling, the specimens were placed in 0.5 percent basic fuchsin dye solution. Dye penetration was evaluated with a stereomicroscope. The data were analyzed with nonparametric tests (P=.05). RESULTS: Laser preparation and prior etching in bur-prepared cavity preparation had no significant effect on enamel sealing (P>.05), but significantly increased microleakage at the dentin margin (P<.001 and P=.001, respectively). Prior etching in laser-prepared cavity preparations significantly improved sealing at the enamel and dentin margins (P=.009 and P=.003, respectively). CONCLUSIONS: Prior acid etching may be necessary to ensure good marginal sealing when laser preparation is used. However, this step is not required when bur cutting is used in primary teeth.

Impact of oxalate desensitizer combined with ethylene-diamine tetra acetic acid-conditioning on dentin bond strength of one-bottle adhesives during dry bonding.

BACKGROUND: Elimination of water entrapment in hybrid layer during bonding procedure would increase bonding durability. AIMS: This study evaluated the effect of oxalate desensitizer (OX) pretreatment on bond strength of three one-bottle adhesives to ethylene-diamine tetra acetic acid (EDTA)-conditioned dentin under dry bonding. MATERIALS AND METHODS: Three adhesive systems, One-Step Plus (OS), Optibond Solo Plus (OP) and Adper Single Bond (SB) were bonded on dentin surfaces under four bonding conditions: (1) Wet-bonding on acid-etched dentin, (2) wet bonding on EDTA-conditioned dentin, (3) dry bonding on EDTA-conditioned dentin, (4) dry bonding associated with OX on the EDTA-conditioned dentin. After storage and thermo cycling, shear bond strength test was performed. Data were analyzed using two-way analysis of variance and Tukey tests. RESULTS: Wet bonding with EDTA or acid etching showed similar bond strength for test adhesives. Dry bonding with EDTA significantly decreased the bond strength of OS, but it had no effect on the bonding of OP and SB. OX application in the forth bonding condition, in comparison with the third condition, had a negative effect on the bond strength of OP, but not influence on OS and SB. CONCLUSIONS: The use of an OX on EDTA-conditioned dentin compromised the bonding efficacy of OS and OP under dry bonding but compatible for SB.

Bond strength of two resin cements to dentin after disinfection pretreatment: effects of Er,Cr:YSGG laser compared with chemical antibacterial agent.

OBJECTIVE: This study compared the effects of two disinfection procedures (2% chlorhexidine [CHX] solution versus Er,Cr:YSGG laser irradiation) on the shear bond strength of ED primer II/Panavia F2.0 (ED/P) and Excite DSC/Variolink N (Ex/V). BACKGROUND DATA: Different methods are used for cavity disinfection prior to adhesive cementation, which may influence the bonding ability of resin cements. METHODS: Flat dentin surfaces were prepared on 100 extracted premolars and randomly divided into 10 groups. In the eight experimental groups, indirect composite samples were cemented with either ED/P or Ex/V under three disinfecting conditions on the dentin surface as follows: (1) CHX application before ED primer II/ after etching, (2) wet laser irradiation (Er,Cr:YSGG laser, 20 Hz, 0.75 W, 15% water +15% air), (3) dry laser irradiation with no water and air cooling. The control groups had no disinfectant application. After 24 h water storage, bond strength test was performed. The data (MPa) were analyzed using two way ANOVA and Tukey tests. RESULTS: The lowest and highest bond strengths were obtained by dry laser and wet laser (10.18±2.67 and 17.36±2.94 for ED/P, 9.64±2.66 and 20.07±3.36 for Ex/V, respectively). For each cement, two-by-two comparisons of four groups revealed significant differences only for dry laser with others (p<0.001). CONCLUSIONS: The use of CHX and Er,Cr:YSGG laser at the low fluences with water/air cooling as the antibacterial agents does not adversely influence the bonding ability of the etch-and-rinse and the self-etch cements.

Witkop tooth and nail syndrome: a report of three cases in a family.

Witkop tooth and nail syndrome is a rare autosomal dominant ectodermal dysplasia manifested by hypodontia and nail dysplasia. Tooth shape may vary, and conical and narrow crowns are common. Mandibular incisors, second molars, and maxillary canines are the most frequently missing teeth. Nail dysplasia affects the fingernails and especially the toenails and is often more severe in childhood. Nails may be spoon-shaped, ridged, slow-growing, and easily broken. We examined an Eastern Mediterranean family in which three siblings (two girls, one boy) had this syndrome. The severity of finger and toenail anomalies varied. The children's mother had no Witkop-related abnormalities, but their father was reported to have dental and nail anomalies. Early intervention is recommended to manage orofacial disfigurement and avoid negative social consequences for these children.