Polyethylene terephthalate clamps : optimization in endodontic and restorative practices

There is a growing search for innovations in dental materials and instruments and, therefore, an increase need to optimize the instruments used in the absolute isolation. The gold standard procedure contributes significantly to the quality of restorativ

Bond strength of a pit-and-fissure sealant associated to etch-and-rinse and self-etching adhesive systems to saliva-contaminated enamel: individual vs. simultaneous light curing

This study evaluated in vitro the shear bond strength (SBS) of a resin-based pit-and-fissure sealant [Fluroshield (F), Dentsply/Caulk] associated with either an etch-and-rinse [Adper Single Bond 2 (SB), 3M/ESPE] or a self-etching adhesive system [Clearfil S3 Bond (S3), Kuraray Co., Ltd.] to saliva-contaminated enamel, comparing two curing protocols: individual light curing of the adhesive system and the sealant or simultaneous curing of both materials. Mesial and distal enamel surfaces from 45 sound third molars were randomly assigned to 6 groups (n=15), according to the bonding technique: I - F was applied to 37% phosphoric acid etched enamel. The other groups were contaminated with fresh human saliva (0.01 mL; 10 s) after acid etching: II - SB and F were light cured separately; III - SB and F were light cured together; IV - S3 and F were light cured separately; V - S3 and F were light cured simultaneously; VI - F was applied to saliva-contaminated, acid-etched enamel without an intermediate bonding agent layer. SBS was tested to failure in a universal testing machine at 0.5 mm/min. Data were analyzed by one-way ANOVA and Fisher's test (α=0.05).The debonded specimens were examined with a stereomicroscope to assess the failure modes. Three representative specimens from each group were observed under scanning electron microscopy for a qualitative analysis. Mean SBS in MPa were: I-12.28 (±4.29); II-8.57 (±3.19); III-7.97 (±2.16); IV-12.56 (±3.11); V-11.45 (±3.77); and VI-7.47 (±1.99). In conclusion, individual or simultaneous curing of the intermediate bonding agent layer and the resin sealant did not seem to affect bond strength to saliva-contaminated enamel. S3/F presented significantly higher SBS than the that of the groups treated with SB etch-and-rinse adhesive system and similar SBS to that of the control group, in which the sealant was applied under ideal dry, noncontaminated conditions.Este estudo avaliou in vitro a resistência ao cisalhamento (RC) de um selante resinoso [Fluroshield (F), Dentsply/Caulk] em associação com um sistema adesivo de condicionamento total [Adper Single Bond 2 (SB), 3M/ESPE] ou auto-condicionante [Clearfil S3 Bond (S3), Kuraray Co., Ltd.] após contaminação salivar do esmalte, comparando dois protocolos: fotopolimerização individual do sistema adesivo e do selante ou simultânea de ambos os materiais. Superfícies mesiais e distais de esmalte de 45 terceiros molares hígidos foram aleatoriamente alocadas em 6 grupos (n=15), de acordo com a técnica adesiva empregada: I - F foi aplicado sobre o esmalte condicionado com ácido fosfórico a 37%. Os demais grupos foram contaminados com saliva (0,01 mL por 10 s) após o condicionamento ácido. II - SB e F foram fotopolimerizados separadamente; III - SB e F foram fotopolimerizados simultaneamente; IV - S3 e F foram fotopolimerizados separadamente; V - S3 e F foram fotopolimerizados simultaneamente; VI - F foi aplicado sobre o esmalte condicionado e contaminado sem sistema adesivo. RC foi testada em uma máquina universal de ensaios (0,5 mm/min; 50 kgf) e os dados analisados por ANOVA a 1 fator e teste exato de Fisher (α=0,05). As interfaces adesivas foram analisadas quanto ao padrão de fraturas em estereomicroscópio. Três espécimes de cada grupo foram analisados qualitativamente em microscópio eletrônico de varredura. As médias de RC em MPa foram: I-12,28 (±4,29); II-8,57 (±3,19); III-7,97 (±2,16); IV-12,56 (±3,11); V-11,45 (±3,77); e VI-7,47 (±1,99). Conclui-se que a fotopolimerização individual ou simultânea do sistema adesivo e do selante não afetou os valores de RC ao esmalte contaminado. S3/F apresentou RC estatisticamente maior do que os grupos tratados com o sistema adesivo etch-and-rinse SB e estatisticamente semelhante ao grupo controle, no qual o selante foi aplicado em condições ideais, na ausência de contaminação salivar

Influence of Single-Nucleotide Polymorphisms on Vitamin D Receptor Expression in Periodontal Ligament Fibroblasts as a Response to Orthodontic Compression

This study aimed to evaluate if single-nucleotide polymorphisms (SNPs) in the vitamin D receptor (VDR) gene are associated with gene expression in human periodontal ligament (hPDL) fibroblasts under simulated orthodontic compressive force. hPDL samples from 57 patients were used. A physiological compressive strain was performed to simulate orthodontic tooth movement in pressure areas under cell culture conditions. The RNA from hPDL fibroblasts was isolated to determine the relative gene expression (mRNA) of the VDR. The DNA was also isolated for the genotyping analysis of five SNPs in the VDR gene: BglI (rs739837, G/T), BsmI (rs1544410, T/C), ApaI (rs7975232, A/C), FokI (rs2228570, A/G), and TaqI (rs731236, A/G). Real-time polymerase chain reaction was used for both analyses. Kruskal–Wallis tests were used to compare VDR expression among genotypes of each SNP. A linear regression analysis was performed to evaluate SNP–SNP interaction. An established alpha of 5% was used. The relative mRNA VDR expression according to the genotypes in the SNPs BglI, BsmI, ApaI, FokI, and TaqI was not statistically significantly different (p > 0.05). The SNP–SNP interaction evaluated by regression analysis did not demonstrate any statistically significant association. No association was observed (p > 0.05). In conclusion, the SNPs BglI (rs739837), BsmI (rs1544410), ApaI (rs7975232), FokI (rs2228570), and TaqI (rs731236) did not show an impact on VDR gene expression in hPDL fibroblasts under simulated orthodontic compressive force

Surface and subsurface erosion of primary enamel by acid beverages over time

This study evaluated the influence of a cola-type soft drink and a soy-based orange juice on the surface and subsurface erosion of primary enamel, as a function of the exposure time. Seventy-five primary incisors were divided for microhardness test (n=45) or scanning electron microscopy (SEM) analysis (n=30). The specimens were randomly assigned to 3 groups: 1 - artificial saliva (control); 2 - cola-type soft drink; and 3 - soy-based orange juice. Immersion cycles in the beverages were undertaken under agitation for 5 min, 3 times a day, during 60 days. Surface microhardness was measured at 7, 15, 30, 45 and 60 days. After 60 days, specimens were bisected and subsurface microhardness was measured at 30, 60, 90, 120, 150 and 200 µm from the surface exposed. Data were analyzed by ANOVA and Tukey’s test (a=0.05). Groups 2 and 3 presented similar decrease of surface microhardness. Regarding subsurface microhardness, group 2 presented the lowest values. SEM images revealed that after 60 days the surfaces clearly exhibited structural loss, unlike those immersed in artificial saliva. It may be concluded that erosion of the surfaces exposed to the cola-type soft drink was more accentuated and directly proportional to the exposure time.Este estudo avaliou a influência de um refrigerante a base de cola e um suco de laranja a base de soja na erosão da superfície e subsuperfície do esmalte do dente decíduo, em função do tempo de exposição. Setenta e cinco incisivos decíduos foram divididos para o teste de microdureza (n=45) ou para a análise em microscópio eletrônico de varredura (MEV) (n=30). Os espécimes foram alocados aleatoriamente em 3 grupos: I - saliva artificial (controle); II - refrigerante a base de cola; e III - suco de laranja a base de soja. Ciclos de imersão nas bebidas foram realizados sob agitação durante 5 min, 3 vezes ao dia, durante 60 dias. A microdureza superficial foi mensurada aos 7, 15, 30, 45 e 60 dias. Após 60 dias, os espécimes foram seccionados e a microdureza subsuperficial foi mensurada aos 30, 60, 90, 120, 150 e 200 μm. Os dados foram analisados pelos testes ANOVA e Tukey (α=5%). Os grupos II e III apresentam uma diminuição similar da microdureza superficial. O grupo II apresentou menores valores de microdureza subsuperficial. As imagens de MEV revelaram que após 60 dias as superficies mostraram perdas de estruturas claramentes identificadas, diferentemente das superfícies imersas em saliva artificial. Pode-se concluir que a erosão das superficies expostas ao refrigerante a base de cola foi mais acentuada e diretamente proporcional ao tempo de exposição à bebida.The authors would like to acknowledge the contribution of Ms. Fatima Rizoli during the development of the experimental period. Authors are also grateful to Dr. Alberto Moreira Jorge Jr. from the Laboratory of Structural Characterization, Department of Material Engineering, Federal University of São Carlos, Brazil, for his assistance during SEM analysi

Investigating the association between dental age and polymorphisms in genes encoding estrogen receptors

Background: Genetic polymorphisms have been shown to influence several physiological traits, including dental and craniofacial characteristics. Understanding the clinical relevance of genetic polymorphisms in dental practice is crucial to personalize treatment plans and improve treatment outcomes. Objective: to evaluate the association between dental age and genetic polymorphisms in genes encoding estrogen receptors alpha and beta (ESR1 and ESR2, respectively) in a sample of Brazilian children. Methodology: This retrospective cross-sectional study was performed with children undergoing orthodontic treatment. Patients with syndromes, congenital anomalies, craniofacial deformities, under hormonal or systemic treatment, and with a previous history of facial trauma were excluded. Panoramic radiographs were used to assess dental age according to the Demirjian, Goldstein, and Tanner method. A delta [dental age-chronological age (DA-CA)] was obtained, which shows whether the patient tends to have a normal, delayed (negative values), or advanced (positive values) dental age. DNA isolated from buccal cells was used to genotype four genetic polymorphisms: rs9340799 (A>G) and rs2234693 (C>T), located in ESR1; and rs1256049 (C>T) and rs4986938 (C>T), located in ESR2. A statistical analysis was performed and values of p<0.05 indicated statistical difference. Results: A total of 79 patients were included, 44 (55.70%) girls and 35 (44.30%) boys. The Demirjian, Goldstein, and Tanner method, in general, overestimated patients’ age by 0.75 years. There was no difference in the delta of dental age between the sexes (p>0.05). Genetic polymorphisms in ESR1 and ESR2 were not associated with dental age (p>0.05). Conclusion: The studied genetic polymorphisms in ESR1 and ESR2 were not associated with dental age in Brazilian childre

Single Nucleotide Polymorphisms in COX2 Is Associated with Persistent Primary Tooth and Delayed Permanent Tooth Eruption

Persistent primary tooth (PPT) is a prevalent clinical condition that occurs when a primary tooth is over-retained beyond the established period of its normal exfoliation time, remaining in the oral cavity. Many factors could be involved in the risk of PPT; therefore, the aim of this study was to evaluate if single nucleotide polymorphisms (SNPs) in the COX2 gene are associated with PPT. Children undergoing orthodontic treatment were screened. Orthopantomographs were assessed to evaluate PPT according to the Nolla stage of its permanent successor. The primary tooth was considered retained when its successor permanent tooth was in Nolla stage 8 and below the alveolar crypt, Nolla stage 9, or Nolla stage 10. A saliva sample from each child was collected and used for DNA extraction. A real-time PCR of two SNPs, rs689466 (−1195 G/A) and rs5275 (+665 T/C), was performed. A chi-square test was used to compare the allele and genotype distribution. Haplotype analysis was also performed. A total of 100 children were included in the study. Fifty-one had at least one PPT, while 49 children were classified as a control. The number of teeth persistent in the oral cavity ranged from 1 to 8. The genotype distribution was associated with PPT in the co-dominant model (p = 0.006) for SNP rs5275. The individuals that carry two T alleles (TT) compared with the individuals that carry at least one C allele (C + TC) had an almost three times higher chance of presenting with PPT (p = 0.012; OR = 2.99, CI95% 1.28 to 6.95–recessive model). The haplotype C-A for the SNPs rs5275 and rs689466, respectively, was significantly associated (p = 0.042). In conclusion, single nucleotide polymorphisms in the gene encoding for COX2 are associated with persistent primary tooth and may delay permanent tooth eruption

Morphological and chemical aspects comparison between enamel and dentin of permanent and deciduous teeth

O objetivo deste estudo in vitro foi avaliar e comparar a microestrutura e a composição mineral do esmalte e da dentina de dentes decíduos e permanentes. Terceiros molares hígidos e segundos molares decíduos foram selecionados e distribuídos aleatoriamente em grupos, de acordo com o método de análise dos substratos utilizado: Microscopia Eletrônica de Varredura (MEV), Espectroscopia de Energia Dispersiva de Raio X (EDX), Difração de Raio X (DRX) e Microscopia Óptica (MO). Foi realizada comparação qualitativa e quantitativa da estrutura dental. As medidas de densidade numérica e diâmetro dos prismas de esmalte/túbulos dentinários e, de espessura do esmalte, dentina e dentina peritubular foram realizadas por meio de fotomicrografias obtidas pela MEV. Os resultados obtidos por meio da SEM foram analisados estatisticamente pelo teste não-paramétrico de Kruskal-Wallis. A quantidade relativa de íons cálcio (Ca) e fósforo (P) foram determinadas por meio de EDX e as fases químicas presentes em ambos os substratos, por análise de DRX. O valor das medidas de espessura observado para o esmalte e dentina dos dentes decíduos foi de 1.14 mm e 3.02 mm, respectivamente. Para os dentes permanentes, obtiveram-se valores de 2.58 mm para o esmalte e 5.95 mm para a dentina. Com relação ao diâmetro da cabeça dos prismas de esmalte, os resultados foram estatisticamente semelhantes para os dentes decíduos e permanentes, demonstrando uma ligeira diminuição do diâmetro da superfície externa para a região próxima a junção amelodentinária (JAD). A densidade numérica dos prismas foi maior nos dentes decíduos, principalmente próximo à JAD, sendo estatisticamente diferente dos valores observados nos dentes permanentes, independente da região analisada. Na análise do diâmetro e densidade numérica dos túbulos dentinários verificou-se semelhança estatística entre os dentes decíduos e permanentes, havendo aumento gradativo do número de túbulos a partir da JAD em direção a região próxima a polpa. A espessura da dentina peritubular, na região próxima a JAD e central foi, respectivamente, 0.91 e 0.59 mm nos dentes decíduos 1.16 e 0.98 mm nos dentes permanentes. A porcentagem de Ca e P foi maior nos dentes permanentes. Observou-se ainda, que a quantidade de colágeno nos dentes decíduos foi aparentemente menor quando analisados por meio da MO. De acordo com os resultados obtidos neste estudo, pode-se concluir que, de maneira geral, os dentes decíduos apresentam menor porcentagem de Ca e P, menor espessura de esmalte e dentina, maior densidade numérica de prismas e dentina peritubular mais delgada quando comparada aos dentes permanentes.This study evaluated in vitro the microstructure and mineral composition of dental enamel and dentin comparing the permanent teeth with the deciduous teeth. Sound third molars and second primary molars were selected and randomly assigned to the following groups, according to the analysis methods of the substrates performed: Scanning Electron Microscopy (SEM), X-Ray diffraction (XRD), Energy dispersive X-ray spectrometer (EDS) and Optical Microscopy (OP). A qualitative and quantitative comparison of the dental structure was done. The measurements of the number and diameter of prisms/tubules, thickness of enamel, dentin and peritubular dentin were done in SEM photomicrographs. The microscopic findings were analyzed statistically by a non-parametric test (Kruskal- Wallis). The relative amounts of calcium (Ca) and phosphorus (P) were determined by EDS investigation. Phase present in both types of teeth were observed by the XRD analysis. The mean thickness measurements observed in the deciduous teeth enamel and dentin was, respectively, 1.14 mm and 3.02 mm and in the permanent teeth, 2.58 mm and 5.95 mm. The mean rod head diameter in deciduous teeth was statistically similar to that of permanent teeth enamel, and a slightly decrease from the outer enamel surface to the region next to the enameldentine junction was assessed. The numerical density of enamel rods was higher in the deciduous teeth, mainly near EDJ, that showed statistically significant difference. The mean tubules number and diameter in deciduous teeth were statistically similar to that of permanent teeth, and this numerical density increased from the EDJ to the region near the pulp. The mean thickness measurements of peritubular dentin observed in the regions near EDJ and central were, respectively, 0.91 and 0.59 mm for the primary teeth / 1.16 and 0.98 mm for the permanent teeth. The percentage of Ca and P was higher in the permanent teeth. The collagen level was apparently lower in deciduous teeth when analyzed by OP. The primary teeth structure showed a lower level of Ca and P and a thinner enamel and dentin thickness. The deciduous enamel presented higher numerical density of rods. The peritubular dentin was thicker in the permanent teeth

Effect of surface treatment and storage on the bond strength of different ceramic systems

Aim: The aim of this study was to evaluate the micro shear bond strength of different ceramic systems - IPS Empress 2, Cergogold, In-Ceram Alumina and Cercon - and a dual luting agent. Methods: Twelve specimens of each ceramic were fabricated and divided according different surface treatments: Group 1: No additional treatment was applied to the ceramic surface; Group 2: Ceramics were etched with 9.5% hydrofluoric acid; Group 3: specimens treated with airborne particle abrasion for each ceramic system in accordance with manufacturer’s instructions (n=20). The tests were performed after 24 h or after water storage for 6 months. Data were then assessed statistically using the 3-way ANOVA and the Tukey’s test (P<0.05). Results: For Cergogold and IPS Empress 2 systems, the treatments performed with airborne particle abrasion and hydrofluoric acid showed no significant differences from each other, and both were superior to the groups without treatment. For Cercon and In-Ceram ceramics, no differences were found among the groups (P<0.05). When the surface was treated with hydrofluoric acid, the highest bond strength was found to IPS Empress 2 in the 6-month storage period (P<0.05). Conclusion: Lower bond strength values were only observed with IPS Empress 2 ceramic for the control group in the 6-month storage (P<0.05)

Effect of surface treatment and storage on the bond strength of different ceramic systems

e aim of this study was to evaluate the micro shear bond strength of different ceramic systems IPS Empress 2, Cergogold, In-Ceram Alumina and Cercon - and a dual luting agent. Methods: Twelve specimens of each ceramic were fabricated and divided according different surface treatments: Group 1: No additional treatment was applied to the ceramic surface; Group 2: Ceramics were etched with 9.5% hydrofluoric acid; Group 3: specimens treated with airborne particle abrasion for each ceramic system in accordance with manufacturers instructions (n=20). The tests were performed after 24 h or after water storage for 6 months. Data were then assessed statistically using the 3-way ANOVA and the Tukeys test (P<0.05). Results: For Cergogold and IPS Empress 2 systems, the treatments performed with airborne particle abrasion and hydrofluoric acid showed no significant differences from each other, and both were superior to the groups without treatment. For Cercon and In-Ceram ceramics, no differences were found among the groups (P<0.05). When the surface was treated with hydrofluoric acid, the highest bond strength was found to IPS Empress 2 in the 6-month storage period (P<0.05). Conclusion: Lower bond strength values were only observed with IPS Empress 2 ceramic for the control group in the 6-month storage (P<0.05)

Effect of the Case for Carpule as a Visual Passive Distraction Tool on Dental Fear and Anxiety: A Pilot Study

The present cross-over study aimed to evaluate the effect of a visual passive distraction tool, a case for carpule, in the management of fear and anxiety during invasive dental treatment. Children between the ages of 4 and 8 years that need at least two treatments with inferior alveolar nerve block were selected. All the included children received two treatments at different moments: in one treatment, local anesthesia was performed with a visual passive distraction tool, the crocodile case, for carpule (experimental); in the other treatment, local anesthesia was performed without the device (control). An evaluation of the anxiety levels was performed by measuring the heart rate and salivary cortisol levels. Wilcoxon&rsquo;s nonparametric test was used for a data analysis (p &lt; 0.05). The mean heart rate with the visual passive distraction device fell from 81.8 to 78.1, while the control rose from 91.4 to 100 (p &lt; 0.05). The mean salivary cortisol levels with the visual passive distraction device fell from 2.0 to 1.6, while in the control, they rose from 2.1 to 2.4 (p &lt; 0.05). In conclusion, the crocodile case for carpule as a visual passive distraction device contributed positively to the management of fear and anxiety during inferior alveolar nerve block in children