Impact of Molar Incisor Hypomineralization on Oral Health-Related Quality of Life in Brazilian Schoolchildren Aged 8 to 10 Years

ABSTRACT Objective: To assess the impact of Molar Incisor Hypomineralization (MIH) and confounding factors on oral health-related quality of life (OHRQoL) according to the perception of 8 to 10-year-old children and their parents/caregivers. Material and Methods: A cross-sectional study including 403 students aged 8-10 years was carried out, in which OHRQoL was measured using the Child Perceptions Questionnaire administered to both children and parents/caregivers. The diagnosis of MIH was performed according to the previously proposed index. Dental caries experience, malocclusion, and sociodemographic factors were evaluated as confounders. Cluster analysis and Poisson regression with robust variance (p<0.05) were performed. Results: The prevalence of MIH was 13.4%. Parents/caregivers of children with MIH in incisors showed a higher impact prevalence in the emotional well-being domain (PR=1.92; 95%CI=1.16-3.19). Children with hypoplasia had a higher prevalence of negative impact on OHRQoL in the oral symptoms domain (PR=1.51; 95%CI=1.03-2.23). According to the perception of parents/caregivers, dental caries experience had a negative impact on the quality of life of students in the emotional well-being domain (PR=4.19; 95%CI=1.06-16.49) and in the total questionnaire score (PR=3.21; 95%CI=1.06-9.71). Conclusion: According to the perception of parents/caregivers, children with MIH in incisors showed a greater impact on OHRQoL. Additionally, the presence of hypoplasia affected the self-perception of OHRQoL in children, and caries experience influenced the OHRQoL of children, as perceived by parents/caregivers.

Clinical implementation of comprehending dentin on a microscopic level

SUMMARY: The aim of the present in vitro study is to visualize dentin to get an in-depth knowledge of the nature of dentin that could provide useful information regarding conditioning dentinal substrate when treating dentinal lesions. Forty-nine extracted human third molars were obtained and prepared to produce artificial dentinal lesions through demineralizing with acetic acid for 7 and 14 days, or lactic acid for 7 days. The teeth were divided into groups and treated with either NaOCl, pepsin, trypsin, or phosphoric acid. To obtain information on the morphology of the treated dentinal surfaces, all samples were visualized under high resolution field emission scanning electron microscope. With high magnification reaching x50000 dentin was clearly visualized together with its constitutes. The effect of various demineralization approaches and various treatment protocols were demonstrated clearly. The relationship between the conditioning procedure steps and the subsequent bond strength was discussed. To our best knowledge, there is no previous clear highly magnified scanning electron microscope images for dentin, and dentinal components and constitutes with and without various treatments. The current in vitro study suggests the complexity nature of dentin as a substrate that should be treated carefully especially with technique sensitive procedures such as adhesive restorations.

El objetivo del presente estudio in vitro fue visualizar la dentina para obtener un conocimiento completo de la naturaleza de ella lo que podría proporcionar información útil sobre el acondicionamiento del sustrato dentinario en el tratamiento de lesiones dentinarias. Se obtuvieron 49 terceros molares humanos extraídos y se prepararon para producir lesiones dentinales artificiales mediante desmineralización con ácido acético por 7 y 14 días, o ácido láctico por 7 días. Los dientes se dividieron en grupos y se trataron con NaOCl, pepsina, tripsina o ácido fosfórico. Para obtener información sobre la morfología de las superficies dentinarias tratadas, todas las muestras se visualizaron bajo un microscopio electrónico de barrido de emisión de campo de alta resolución. Con un gran aumento que alcanzó x50000, la dentina se visualizó claramente junto con sus componentes. Se demostró el efecto de varios enfoques de desmineralización y varios protocolos de tratamiento. Se discutió la relación entre los pasos del procedimiento de acondicionamiento y la subsiguiente fuerza de unión. Hasta donde sabemos, no hay imágenes claras previas de microscopio electrónico de barrido altamente ampliadas para la dentina y los componentes y constituyentes de la dentina con y sin diferentes tratamientos. El estudio in vitro actual sugiere la naturaleza compleja de la dentina como sustrato que debe tratarse con cuidado, especialmente en los procedimientos sensibles a la técnica, tal como las restauraciones adhesivas.

Effects of novel bioactive glasses on promoting remineralization of artificial dentin caries / 北京大学学报(医学版)

OBJECTIVE@#To investigate the effects of novel bioactive glasses (BG) including PSC with high phosphorus component and FBG with fluorine-doped element on promoting remineralization of artificial dentin caries.@*METHODS@#(1) BGs were used in this study as follows: PSC (10.8%P2O5-54.2%SiO2-35.0%CaO, mol.%) were synthesized using phytic acid as the phosphorus precursor through sol-gel method. FBG (6.1%P2O5-37.0%SiO2-53.9%CaO-3.0%CaF2, mol.%) and 45S5(6.0%P2O5-45.0%SiO2-24.5%CaO-24.5%Na2O, mol.%) were synthesized by traditional melt method. (2) The above BGs were soaked in simulated body fluid (SBF) for 24 hours. Then X-ray diffraction (XRD) was used to analyze the formation of hydroxyapatite (HA) crystals. (3) Prepared 1 mm thick dentin slices were soaked in 17% ethylene diamine tetraacetic acid (EDTA) for 1 week to demineralize the dentin. Then the dentin slices treated by BG were soaked in SBF for 1 week. Field emission scanning electron micro-scopy (FE-SEM) was used to observe the surface morphology of the dentin slices. (4) Four cavities were prepared to 1 mm depth in each 2 mm thick dentin slice, then were treated with lactic acid for 2 weeks to form the artificial dentin caries. Wax, mineral trioxide aggregate (MTA), PSC and FBG were used to fill four cavities as blank control group, MTA group, PSC group and FBG group respectively. Then the spe-cimens were soaked in SBF for 4 weeks. The changes of depth and density of demineralized dentin were analyzed using Micro-CT before filling and after 2 and 4 weeks filling.@*RESULTS@#(1) PSC and FBG promoted mineral formation on the surfaces of the demineralized dentin. And the speed was faster and crystallinity was higher in PSC group than the FBG and 45S5 groups. (2) The increased mineral density of artificial dentin caries in PSC group were (185.98 ± 55.66) mg/cm3 and (213.64 ± 36.01) mg/cm3 2 and 4 weeks after filling respectively, which were significantly higher than the control group [(20.38 ± 7.55) mg/cm3, P=0.006; (36.46 ± 10.79) mg/cm3, P=0.001]. At meanwhile, PSC group was also higher than MTA group [(57.29 ± 10.09) mg/cm3; (111.02 ± 22.06) mg/cm3], and it had statistical difference (P=0.015; P=0.006). The depth of remineralized dentin in PSC group were (40.0 ± 16.9) μm and (54.5 ± 17.8) μm 2 and 4 weeks respectively, which were also statistically different from the control group (P =0.010;P=0.001). There were no statistical differences between the control group and MTA group. The above effects of FBG group were between PSC and MTA.@*CONCLUSION@#PSC has advantages in the speed, quality and depth of mineral deposition in the demineralized layer of artificial dentin caries. It would be expected to be an ideal material to promote the remineralization of dentin caries.

Influência do tipo de agente espessante e da suplementação de cálcio e fósforo no efeito desmineralizante de géis clareadores a base de peróxido de hidrogênio / Influence of the type of thickening agent and supplementation of calcium and phosphate on the demineralizing effect of bleaching gels based on hydrogen peroxide

O estudo avaliou o efeito da adição de cálcio (Ca) e fósforo (P), em quantidade correspondente ao ponto de saturação (PS) e ao coeficiente de solubilidade (CS), a géis clareadores contendo diferentes agentes espessantes na desmineralização do esmalte dentário. Foram manipulados géis clareadores contendo peróxido de hidrogênio (PH) a 35% e utilizados os espessantes carbopol 980 (CB); aerosil 200 (SP); poloxamer 407 (PX); goma guar (GG) e hidroxietilcelulose (HEC). Foram realizadas leituras iniciais da microdureza Knoop do esmalte empregando um microdurômetro, da rugosidade superficial em um perfilômetro de contato e da cor utilizando espectrofotômetro colorimétrico de reflectância. Os espécimes foram divididos em 5 grupos experimentais de acordo com o tipo de espessante. Cada grupo foi dividido em três subgrupos (n=20), de acordo com a suplementação mineral (0- nenhuma suplementação; PS ­ adição de Ca e P de acordo com o PS calculado para aquele espessante; CS ­ adição da quantidade máxima de Ca e P de acordo com o CS). Além disso, três grupos controles (n=20) foram preparados, sendo eles: CN (controle negativo ­água ultrapura); CP (controle positivo ­ PH a 35% sem a adição de qualquer mineral); CC (controle positivo comercial - gel comercial Whiteness HP). Sobre cada espécime foram aplicados 0,050 g dos respectivos géis clareadores, durante 45 min. Os dados dos grupos experimentais foram analisados estatisticamente com ANOVA a 2 fatores (TIPO DE ESPESSANTE x ADIÇÃO DE SAIS DE CA E P) e teste de Tukey. A comparação com os grupos controle foi realizada com o teste de Dunnett ( = 5%). Para todas as mensurações realizadas, a ANOVA mostrou diferenças significativas para os dois fatores (p<0,05). Para a alteração da microdureza, os resultados do teste de Tukey foram: TIPO DE ESPESSANTE (p=0,0001): HEC ­ 15,40(6,97)a, GG - 10,31(5,78)b, CB - 7,49(2,87)c, PX - 4,60(4,96)d, SP - 0,57(2,43)e; ADIÇÃO (p=0,0001): 0 - 12,34(7,22)a, S -10,31(5,76)b, CS -7,49(6,09)c. Para a alteração da rugosidade (p=0,0001), os resultados foram: TIPO DE ESPESSANTE (p=0,0001): SP - 5,19(23,36), GG - 9,70(17,75)ab, PX - 15,95(20,79)b, HEC - 53,58(71,82)c, CB - 55,49(63,69)c; ADIÇÃO (p=0,0001): 0 - 79,62(58,70)a, S - 3,23(12,08)a, CS - 1,09(9,44)b. Para a mudança de cor (ΔE), os resultados foram: TIPO DE ESPESSANTE (p=0,0001): SP - 5,40(2,92)a, GG - 3,13(1,83)a, PX - 3,18(2,57)ab, HEC - 3,82(2,05)bc, CB - 4,79(3,26)c. ADIÇÃO (p=0,2853): 0 - 4,37(2,60)a, S - 4,04(3,07)a, CS - 3,79(2,42)a. Os resultados para o teste de Dunnett para a microdureza: os grupos SP, SP-S e SP-CS não demonstraram diferenças com o grupo CN, e apenas os grupos GG e HEC-S não demostraram diferenças com o grupo CP e o grupo HEC-S para o CPC. Para a rugosidade, os grupos CB-CS, SP, PX-S, PX-CS, GG-S e GG-CS não demonstraram diferenças em relação ao grupo CN e todos os grupos apresentaram diferenças significativas para os grupos CP e CPC. Mediante os resultados desse estudo, podemos concluir que: A adição de cálcio e/ou fósforo em quantidades correspondente ao PS ou ao CS apenas do grupo SP impediu a queda da dureza e o aumento da rugosidade. Os demais grupos apresentaram alterações, porém sem afetar o tratamento clareador. (AU)

The aim of the study was to evaluate the effect of adding calcium (Ca) and phosphorus (P), in amounts corresponding to the saturation concentration (SC) and the solubility limit (SL), to bleaching gels containing different thickening agents on the demineralization of tooth enamel. Bleaching gels containing 35% hydrogen peroxide (PH) were manipulated and the thickeners were used: carbopol 980 (CB); aerosil 200 (SP); poloxamer 407 (PX); guar gum (GG) and hydroxyethylcellulose (HEC). The baseline readings of Knoop microhardness of the enamel using a microhardness, surface roughness using a contact profilometer and color using a colorimetric reflectance spectrophotometer were taken. The specimens were divided into 5 experimental groups according to the type of thickener. Each group was divided into three subgroups (n=20), according to mineral supplementation (0 - no supplementation; SC - addition of Ca and P according to the SC calculated for that thickener; SL - addition of the maximum amount of Ca and P according to SL). In addition, three control groups (n=20) were prepared, namely: NC (negative control ­ ultra pure water); PC (positive control ­ 35% pH without the addition of any mineral); CC (commercial positive control - commercial Whiteness HP gel). Were applied 0.050 g of the respective bleaching gels to each specimen for 45 min. The microhardness and surface roughness of the samples were measured immediately after bleaching. All samples were then immersed in artificial saliva for 7 days and the final color evaluated. Data from the experimental groups were statistically analyzed with 2-way ANOVA (THICKENER TYPE x MINERAL SUPPLEMENTATION) and Tukey test. Comparison with control groups was performed using Dunnett's test ( = 5%). For all measurements performed, ANOVA showed significant differences for the two factors (p<0.05). For microhardness change, the Tukey test results were: THICKENER TYPE (p=0.0001): HEC - 15.40(6.97)a, GG - 10.31(5.78)b, CB - 7.49(2.87)c, PX - 4 .60(4.96)d, SP - 0.57(2.43)e; ADDITION (p=0.0001): 0 - 12.34(7.22)a, SC -10.31(5.76)b, SL -7.49(6.09)c. For roughness change (p=0.0001), the results were: TYPE OF THICKENER (p=0.0001): SP - 5.19(23.36), GG - 9.70(17.75)ab, PX - 15.95(20.79)b, HEC - 53.58(71.82)c, CB - 55.49(63.69)c; ADDITION (p=0.0001): 0 - 79.62(58.70)a, SC - 3.23(12.08)a, SL - 1.09(9.44)b. For the color change (ΔE), the results were: TYPE OF THICKENER (p=0.0001): SP - 5.40(2.92)a, GG - 3.13(1.83)a, PX - 3.18(2.57)ab, HEC - 3.82(2.05)bc, CB - 4.79(3.26)c. ADDITION (p=0.2853): 0 - 4.37(2.60)a, SC - 4.04(3.07)a, SL - 3.79(2.42)a. The results for the Dunnett test for microhardness were: the SP, SP-S and SP-CS groups did not show differences with the CN group, and only the GG and HEC-S groups did not show differences with the CP group and the HEC-S for the CPC. For roughness, the CB-CS, SP, PX-S, PX-CS, GG-S and GG-CS groups did not show differences in relation to the CN group and all groups showed significant differences for the CP and CPC groups. By the results of this study, we can conclude that: The addition of calcium and/or phosphorus in amounts corresponding to the SC or to the SL of the aerosil group only prevented the drop in hardness and the increase in roughness. (AU)

In vitro effect of low-fluoride toothpaste supplemented with sodium trimetaphosphate, xylitol, and erythritol on enamel demineralization

Abstract Regular use of toothpaste with fluoride (F) concentrations of ≥ 1000 ppm has been shown to contribute to reducing caries increment. However, when used by children during the period of dental development, it can lead to dental fluorosis. Objective: In this study, we aimed to evaluate the in vitro effect of a toothpaste formulation with reduced fluoride (F) concentration (200 ppm) supplemented with sodium trimetaphosphate (TMP: 0.2%), Xylitol (X:16%), and Erythritol (E: 4%) on dental enamel demineralization. Methodology: Bovine enamel blocks were selected according to initial surface hardness (SHi) and then divided into seven experimental toothpaste groups (n=12). These groups included 1) no F-TMP-X-E (Placebo); 2) 16% Xylitol and 4% Erythritol (X-E); 3) 16% Xylitol, 4% Erythritol and 0.2%TMP (X-E-TMP); 4) 200 ppm F (no X-E-TMP: (200F)); 5) 200 ppm F and 0.2% TMP (200F-TMP); 200 ppm F, 16% Xylitol, 4% Erythritol, and 0.2% TMP (200F-X-E-TMP); and 7) 1,100 ppm F (1100F). Blocks were individually treated 2×/day with slurries of toothpastes and subjected to a pH cycling regimen for five days (DES: 6 hours and RE: 18 hours). Then, the percentage of surface hardness loss (%SH), integrated loss of subsurface hardness (ΔKHN), fluoride (F), calcium (Ca), and phosphorus (P) in enamel were determined. The data were analyzed by ANOVA (1-criterion) and the Student-Newman-Keuls test (p<0.001). Results: We found that the 200F-X-E-TMP treatment reduced %SH by 43% compared to the 1100F treatments (p<0.001). The ΔKHN was ~ 65% higher with 200F-X-E-TMP compared to 1100F (p<0.001). The highest concentration of F in enamel was observed on the 1100F treatment (p<0.001). The 200F-X-E-TMP treatment promote higher increase of Ca and P concentration in the enamel (p<0.001). Conclusion: The association of 200F-X-E-TMP led to a significant increase of the protective effect on enamel demineralization compared to the 1100F toothpaste.

Research on the effects of tooth demineralization prevention with Duraphat frequently used in orthodontic patients / 口腔医学

Objective@#To investigate the effect of frequently used Duraphaton preventing dental demineralization of patients with fixed orthodontic appliances. @*Methods@# A total of 50 orthodontic patients wearing fixed appliances at Department of orthodontics, Affiliated Stomatological Hospital, Nanjing Medical University from June to December 2021 were selected as study subjects by convenient sampling method. They were then randomly divided into experimental group and control group according to random numbers. The experimental group received high-frequency fluoride treatment for unilateral maxillary lateral incisors and no treatment on the contralateral side. Meanwhile, the control group received placebo treatment for unilateral maxillary lateral incisors and no treatment on the contralateral side. Each patient was followed up for 6 months. The initial and final photographs of patients' maxillary lateral incisors were observed and scored to determine the mean demineralization progression index for each group.@*Results@#The difference in mean demineralization progression index was statistically significant when comparing different groups(P<0.05), and the lowest incidence of demineralization was reported in the Duraphattreated group (0.960±0.465), followed respectively by the fluoride-free control group (1.213±0.713), the placebo control group (1.267±0.720) and the placebo treatment group (1.307±0.713). @*Conclusion@#High frequency use of Duraphatis is effective in reducing the incidence of demineralization in patients with fixed orthodontic appliances.

Effect of Stevia rebaudiana Bertoni infusion on enamel demineralization and dental biofilm formation: an in-situ study / Efeito da infusão de Stevia rebaudiana Bertoni na desmineralização do esmalte e na formação do biofilme dental: um estudo in situ

Aim: Stevia rebaudiana Bertoni (Stevia) is a natural non--caloric sweetener that can modify the cariogenicity of biofilms. This study aimed to evaluate the effect of Ste-via infusion in microbial and biochemical composition of biofilms formed in the presence of sucrose and on enamel demineralization. Materials and Methods: In a cross-over design, eleven volunteers wore an intraoral palatal appliance containing 4 slabs of bovine enamel during 3 phases of 7 days each. Sucrose solution (20%) was dripped onto slabs 8 times/day and 0.9% sodium chloride (NaCl), 0.12% chlorhexidine (CHX), or 5% infusion of Stevia were dripped 2x/day. Biofilm formed on the slabs was collected and analyzed for counts of microorganisms (total bacteria, Lactobacilli, Candida spp., and Streptococcus mutans) biochemical composition in terms of soluble and insoluble extracellular polysaccharides and qualitative assessment by scanning electron microscopy. The per-centage of surface hardness loss (%SHL) was determined on enamel slabs taken baseline and post-biofilm Knoop surface hardness values. Results: The % SHL in the CHX treatment was statistically lower in comparison to NaCl (p < 0.05). No differences were found between Stevia and CHX and between Stevia and NaCl. No other difference was found among the experimental groups with respect to the other outcomes. Discussion: Under high carioge-nic conditions resembling frequent exposure to sucrose and absence of mechanical disruption, use of Stevia can neither modify the counts of cariogenic microorganisms nor the concentration of extracellular polysaccharides on in situ formed biofilms. This may have occurred due to the exposure of the biofilm to high sucrose concentration for all treatments and the condi-tion of the microorganism growth in situ, which may hinder the diffusion of substances through the thick biofilm. Conclusion: Biofilm exposed to a high cariogenic challenge and without mechanical disruption is not affected by an infusion of Stevia rebaudiana Bertoni.

Objetivo: A Stevia rebaudiana Bertoni (Stevia) é um adoçante natural não calórico que pode modificar a cariogenicidade de biofilmes. Este estudo teve como objetivo avaliar o efeito da infusão de Stevia na composição microbiana e bioquímica de biofilmes formados na presença de sacarose e na desmineralização do esmalte. Materiais e métodos: Em um desenho cruzado, onze voluntários usaram um aparelho intraoral palatino contendo 4 pla-cas de esmalte bovino durante 3 fases de 7 dias cada. A solução de sacarose (20%) foi gotejada em placas 8 vezes/dia e cloreto de sódio a 0,9% (NaCl), clorexidina a 0,12% (CHX) ou infusão a 5% de Stevia foram gotejados 2x/dia. O biofilme formado nas placas foi coletado e analisado para contagem da composição bioquímica de microrganismos (bactérias totais, Lactobacilos, Candida spp. e Streptococcus mutans) em termos de polissaca-rídeos extracelulares solúveis e insolúveis e avaliação qualitativa por microscopia eletrônica de varredura. A porcentagem de perda de dureza superficial (%SHL) nos blocos de esmalte foi determinada com base nos valores de dureza superficial Knoop tomadas no início e pós-biofilme. Resultados: O % SHL no tratamento CHX foi estatisticamente menor em comparação ao NaCl (p < 0,05). Não foram encontradas diferenças entre Stevia e CHX e entre Stevia e NaCl. Nenhuma outra diferença foi encontrada entre os grupos experimentais em re-lação aos outros resultados. Discussão: Sob condições cariogênicas elevadas que se assemelham a exposição frequente à sacarose e ausência de disrupção mecânica, o uso de Stevia não pode modificar as contagens de microrganismos cariogênicos nem a concentração de polissacarídeos extracelulares em biofilmes formados in situ. Isso pode ter ocorrido devido à exposição do biofilme à alta concentração de sacarose para todos os tratamentos e à condição de crescimento do microrganismo in situ, o que pode dificultar a difusão de substâncias através do biofilme espesso. Conclusão: O biofilme exposto a um alto desafio cariogênico e sem disruptucao mecânica não é afetado por uma infusão de Stevia rebaudiana Bertoni.

Comparative Effectiveness of Herbal and Conventional Toothpaste on Prevention of Dental Caries: Systematic Review and Meta-Analysis

Dental caries is a global oral health problem caused due to localized demineralization of the enamel. Chemical plaque control is used as an adjuvant to mechanical plaque control in removing biofilm, thereby preventing dental caries. In recent times, there has been a renewed interest in nature?based products. This systematic review aimed to analyse the existing literature to compare the effectiveness of herbal and conventional dentifrices on prevention of dental caries. A search was done in the databases of PubMed and Google Scholar in July 2020 for the related topic. A hand search was done from the references of primary studies and other clinical trial registry sites. Randomized control trials, comparative clinical trials, and in vitro studies in which the effectiveness of herbal and conventional dentifrices on prevention of dental caries were included after review by the reviewers. The systematic search revealed a total of thirty?two publications from which ten publications were included. Five studies were clinical studies and five were in vitro studies. All the studies used microbiological analysis for the determination of cariogenic microorganisms in plaque and saliva, whereas one study used pH of plaque and saliva. Among the included studies, all studies had a high risk of bias with level 2 evidence. With the evidence available, it can be concluded that herbal dentifrices and fluoride dentifrices have similar antimicrobial activity against cariogenic microorganisms.

Quantification of sugar intake and mineralization of teeth in 13–15-year-old subjects – A pilot study

Background: Dental caries begins with the initiation of demineralization which is a reversible process. Diet, especially intake of sugar, is an important aetiological factor for demineralization of enamel which eventually leads to caries. Aim: This study aims to understand the quantitative relationship between sugar consumption and mineralization by finding out the change in mineralization of teeth as a result of the change in the sugar score. Settings and Design: This interventional study was done among 119 teeth of 19 subjects who were between the ages of 13–15 years in Hubli city. Materials and Methods: Sugar score was calculated from a 5-day diet history of the subjects and a DIAGNOdent pen was used to indicate the mineralization value of the teeth before the intervention. Diet counseling was given as an intervention after which sugar score and DIAGNOdent scores were measured again after 14 days and compared with the baseline values. Statistical Analysis: Descriptive statistics and a linear regression analysis was done to determine the relationship between the variables. Results: Sugar score and DIAGNOdent score after 14 days were found to have reduced significantly by 41.6% and 20.3% respectively from the baseline values. The Linear Regression indicated that a reduction of sugar score by 5 resulted in a decrease of DIAGNOdent score by 0.16. Conclusion: The findings of the present study suggest that the modification of sugar consumption brought about a significant improvement in the mineralization of the demineralized teeth thus making diet counseling an effective preventive strategy for caries prevention.

Experimental composite containing silicon dioxide-coated silver nanoparticles for orthodontic bonding: Antimicrobial activity and shear bond strength

ABSTRACT Objective: This study aimed to investigate the antimicrobial activity and shear bond strength (SBS) of orthodontic brackets to bovine enamel using experimental composites with different concentrations of silicon dioxide-coated silver nanoparticles (Ag@SiO2 NPs). Methods: Fifty bovine incisors were divided into five groups according to the composite (n = 10): G1 - Control Group (Transbond XT Resin), G2 - Experimental composite without Ag@SiO2 NPs; G3 - Experimental composite with 0.5% of Ag@SiO2 NPs; G4 - Experimental composite with 1% of Ag@SiO2 NPs; G5 - Experimental composite with 3% of Ag@SiO2 NPs. The SBS test was performed using a universal mechanical testing machine, and the adhesive remnant index (ARI) was analyzed by optical microscopy. For the antimicrobial activity evaluation, Streptococcus mutans (S. mutans) biofilm was formed for three days in hydroxyapatite discs. Posteriorly, S. mutans colony forming units (CFU) were evaluated. For SBS analysis, Analysis of Variance was used, followed by the Tukey test, at a 5% statistical significance level. The CFU data were analyzed by Kruskal-Wallis, followed by Dunn as a post-hoc test. The ARI results were analyzed descriptively. Results: There was no statistically significant difference in SBS values between the experimental and control groups (p>0.05). A 3% incorporation of Ag@SiO2 NPs statistically reduced the SBS values (p<0.05) compared to the 1% group. The addition of 3% of Ag@SiO2 NPs to the composites significantly reduced S. mutans biofilm formation, compared to group G2 (p<0.05). Conclusion: Composites incorporating 3% of Ag@SiO2 NPs presented similar SBS values compared to the control group, and showed significant antimicrobial activity.

RESUMO Objetivo: O presente estudo objetivou investigar a atividade antimicrobiana e a resistência de união ao cisalhamento (RU) de braquetes ortodônticos colados em esmalte bovino, utilizando compósitos experimentais com diferentes concentrações de nanopartículas de prata revestidas com dióxido de silício (NPs Ag@SiO2). Material e Métodos: Cinquenta incisivos bovinos foram divididos em cinco grupos, de acordo com o compósito utilizado (n = 10): G1 - Grupo Controle (Resina Transbond XT); G2 - Compósito Experimental sem NPs Ag@SiO2; G3 - Compósito Experimental com 0,5% de NPs Ag@SiO2; G4 - Composto Experimental com 1% de NPs Ag@SiO2; e G5 - Compósito Experimental com 3% de NPs Ag@SiO2. O teste de RU foi realizado em máquina universal de ensaios mecânicos, e o índice de adesivo remanescente (IAR) foi analisado por microscopia óptica. Para a avaliação da atividade antimicrobiana, biofilme de S. mutans foi formado por três dias em discos de hidroxiapatita. Posteriormente, foram avaliadas as unidades formadoras de colônias (UFC) de S. mutans. Para a análise de RU, foi utilizada a Análise de Variância, seguida do teste de Tukey, com nível de significância estatística de 5%. Os dados de UFC foram analisados por meio do teste de Kruskal-Wallis, seguido do teste post-hoc de Dunn. Os resultados de IAR foram analisados descritivamente. Resultados: Não houve diferença estatisticamente significativa nos valores de RU entre os grupos experimentais e o grupo controle (p> 0,05). A incorporação de 3% de NPs Ag@SiO2 reduziu estatisticamente os valores de RU (p< 0,05), em comparação ao grupo com 1%. A adição de 3% de NPs Ag@SiO2 ao compósito reduziu significativamente a formação de biofilme de S. mutans, em relação ao grupo G2 (p< 0,05). Conclusão: Os compósitos com incorporação de 3% de NPs Ag@SiO2 apresentaram valores de RU semelhantes ao grupo controle e demonstraram significativa atividade antimicrobiana.

A conservative approach to rehabilitate a molar-incisor hypomineralization case / Uma abordagem conservadora para reabilitar um caso de hipomineralização molar-incisivo

ABSTRACT Molar incisor hypomineralization is an increasingly common condition in our population. This condition can have great impact on the esthetics, function, and well-being of the child. This paper reports a case of a young patient diagnosed with this condition affecting all the first permanent molars and lower incisors, particularly teeth 31 and 41. The molars were treated with direct resin restorations with cusp coating and the incisors aesthetic was restored with different techniques such as bleaching with sodium hypochlorite, micro-abrasion and resin restorations. This treatment plan aimed to restore the proper teeth function, treat the already existing hypersensitivity and algic complains and to improve the aesthetic of the anterior sector. The presented case shows a conservative approach to deal with the molar incisor hypomineralization condition with satisfactory results after 1-year follow-up.

RESUMO A hipomineralização incisivo-molar (HIM) é uma condição cada vez mais comum na nossa população. Esta condição pode ter um grande impacto na estética, função e bem-estar da criança. Este artigo relata um caso de um paciente jovem diagnosticado com esta condição afetando todos os primeiros molares permanentes e incisivos inferiores, principalmente os dentes 31 e 41. Os molares foram tratados com restaurações diretas em resina composta com recobrimento de cúspides e a estética dos incisivos foi restabelecida com diferentes técnicas, como branqueamento com hipoclorito de sódio, micro-abrasão e restaurações de resina composta. Este plano de tratamento teve como objetivo restaurar a função dos dentes, tratar a hipersensibilidade e as queixas álgicas já existentes e melhorar a estética do sector anterior. O caso apresentado mostra uma abordagem conservadora para lidar com casos de hipomineralização incisivo-molar com resultados satisfatórios após 1 ano de acompanhamento.

Effect of fluoride, chlorhexidine or Nd:YAG on the progression of root dentin demineralization after removal of the demineralized organic matrix

Abstract Quantification of collagen degradation is an important parameter to evaluate dentin caries for preventive aid. Objectives: Evaluate preventive methods against root collagen degradation by the hydroxyproline assay (HYP) and microradiography technique (MRT). Methodology: Five bovine root dentin blocks were obtained and subjected to an artificial demineralization process by acetate buffer (pH 5) to induce carious lesion formation. Samples were subjected to the following therapeutic treatments: 1) 0.12% chlorhexidine for 1 min, 2) 2% fluoride for 1 min, 3) Nd:YAG Laser (400 μm diameter optical fiber, 10 Hz frequency, 60 mJ/pulse energy, 48 J/cm2 energy density, in noncontact mode for 10 s), 4) deionized water (control) for 1 min, 5) MRT control group (without treatment and removal of collagen). Samples were exposed to degradation by a collagenase enzyme for five days. The enzyme solution was collected, by colorimetry in a spectrophotometer, from the collagen matrix for the hydroxyproline release analysis. The same samples were subjected to an additional two days of demineralization to induce the progression of mineral loss. Samples were analyzed by MRT for the visualization of their degraded areas (estimation of lesion depth and mineral loss). ANOVA was applied to compare hydroxyproline release rates. MRT data were subjected to the Kruskal-Wallis test, followed by the Dunn's test. Comparisons between the initial five-day and the subsequent two-day demineralization processes were performed by repeated t-test or Wilcoxon (p<0.05) measurements. Results: The amount of HYP released from the dentin samples failed to show significant differences among the groups (p=0.09). Fluoride and chlorhexidine were able to interact with the samples, reducing the progression of dentin caries after removal of the demineralized organic matrix. CHX was the only treatment able to show significant lower lesion depth than the negative control. Conclusion: Chlorhexidine and fluoride were effective in reducing root caries progression.

Effect of Xylitol Varnishes on the Inhibition of Demineralization in Vitro

Abstract Objective: To evaluate the efficacy of xylitol varnishes in the inhibition of enamel demineralization in vitro. Material and Methods: Bovine enamel blocks (n=120) were randomly allocated to four groups (n = 30), and the surface hardness (SH) was measured at baseline. The blocks were treated with the following varnishes: 20% xylitol, 20% xylitol plus F (5% NaF), Duraphat™ (5% NaF, positive control), and placebo (no-F/xylitol, negative control). The varnishes were applied and removed after 6 h of immersion in artificial saliva. The blocks were subjected to pH cycles (demineralization and remineralization for 2 and 22h/day, respectively, for 8 days). Surface and cross-sectional hardnesses were measured to calculate the percentage of SH loss (%SHL) and the integrated loss of the subsurface hardness (ΔKHN). Data were statistically analyzed using Kruskal-Wallis and Tukey's tests (p<0.05). Results: %SHL was significantly decreased by 20% xylitol plus F, Duraphat™, and 20% xylitol varnishes compared to placebo. The use of 20% xylitol plus F varnish led to a significantly lower percentage of SH loss compared to the use of 20% xylitol varnish without F. However, the experimental and commercial varnishes led to significantly lower subsurface demineralization compared to placebo and did not differ from each other. Conclusion: Xylitol varnishes, especially when combined with F, effectively prevent enamel demineralization (AU).

Application of nanoparticles in preventing enamel demineralization during orthodontics / 口腔疾病防治

@#Enamel demineralization is one of the most common adverse reactions to orthodontic treatment. The existence of orthodontic appliances affects oral hygiene maintenance, which easily leads to plaque accumulation and oral flora dysbiosis, and cariogenic bacteria produce acid to cause enamel demineralization. It not only affects aesthetics but may develop into caries and endanger oral health. Therefore, enamel demineralization has become an urgent problem. Nanoparticles generally refer to solid particles with diameters of 1 to 100 nm and have unique physicochemical properties that provide a new strategy for preventing enamel demineralization during orthodontics. Reviewing the relevant literature, nanoparticles used for the prevention of enamel demineralization in orthodontics may be classified into antibacterial, remineralization and carrier-type nanoparticles according to their functions. Most research was performed on the application of nanoparticles to modify orthodontic adhesives for enhancement of antibacterial or remineralization properties, but some studies also focused on the modification of orthodontic appliances with nanoparticles for surface coating or overall doping to provide antimicrobial properties. The advantage of these two approaches is that they are not dependent on patient compliance. Nanoparticle-modified fluoride varnishes and nanocarriers loaded with antimicrobial or remineralization agents may be used to promote oral health care in orthodontic patients, which have a sustained preventive effect but depend on the cooperation of the patient. It was indicated that the small size effect of nanoparticles provides better performance, but there may be certain safety issues, and there is still some influence on the physicochemical properties of the modified materials themselves. These issues must be further explored. Although there are some limitations in the current studies, nanoparticles are expected to play an important role in the prevention of enamel demineralization during orthodontics in the future.

Prevalence and predisponent factors of molar-incisor hypomineralization in primary dentition

Aim: To evaluate the prevalence and predisposing factors for hypomineralization of second molars in children in primary dentition. Methods: A questionnaire was applied to parents to analyze predisposing factors and to assist in the diagnosis of hypomineralization in children between 2 and 6 years old, followed by an intraoral examination based on indices of non-fluorotic enamel defects in the primary dentition, according to the "Modified Index DDE" to determine demarcated opacity and HSPM presence / severity index to assess hypomineralization. Children from public and private schools were dived into two groups: if they presented HSPM-Group 1 (G1) and if they did not have HSPM-Control group (CG). Results: The most frequent predisposing factors associated with the child were Illness in the first year of life (X2= 6.49; p=0.01) and antibiotic use in the first year of life (X2= 41.82; p= 0.01). The factors associated with the mother were hypertension (X2= 9.36; p=0.01), infections during pregnancy (X2=14.80; p=0.01) and alcohol consumption during pregnancy (X2=97.33; p=0.01). There was a prevalence of 3.9% of HSPM in 14 children, with statistical difference regarding gender (X2 = 4.57; p <0.05), with boys presenting a higher frequency. In G1 hypomineralization was of the type with demarcated opacity, with more prevalent characteristics the yellowish spot, with moderate post-eruptive fracture and acceptable atypical restorations. All lesions were located in the labial region with 1/3 of extension. Conclusion: The prevalence of HSPM in children between 2 and 6 years old was 3.9%, with a predominance in males, with tooth 65 being the most affected. There was an association between HSPM and infection in the first year of life, as well as the use of antibiotics and sensitivity in the teeth affected by the lesion. There was an association between HSPM and hypertension, infection and mothers' alcohol use during pregnancy

Influence of topical fluoride on shear bond strength of orthodontic brackets and enamel white spot lesions formation / Influência do flúor tópico na resistência ao cisalhamento de braquetes ortodônticos e na formação de lesões de manchas brancas no esmalte

Introduction Fluoride is considered a key element in the remineralization process of tooth enamel. Objective To evaluate the influence of a topical solution of sodium fluoride (NaF) on the shear bond strength of orthodontic brackets and white spot lesions formation. Material and method Sixty bovine teeth were divided into three groups (n=20). Group 1 (Control): shear bond strength; Group 2: shear bond strength after pH cycling; Group 3: shear bond strength after pH cycling and treatment with 0.04% NaF solution. Groups 2 and 3 underwent pH cycling with demineralizing (6hs) and remineralizing (17hs) solutions at pH of 4.3 and 7.0 respectively for 15 days. The specimens were submitted to the shear bond strength and the Adhesive Remnant Index was verified (ARI). The specimens of each group (n=3) were qualitatively analyzed by means of Scanning Electron Microscopy (SEM). Kruskal-Wallis test assessed the shear bond strength and Fisher's exact test evaluated ARI, with significance level of 5%. Result There was no significant difference among the three groups in shear bond strength (p=0.2679). Significant difference was found in ARI (p=0.0199). The frequency of ARI 1 was 55% in group 1, 90% in group 2, and 80% in group 3. SEM showed difference between the enamel and bonding. Group 2 showed structural change of the enamel surface, adjacent to the bond area; and group 3 showed enamel with characteristics similar to those of group 1. Conclusion It was concluded that there was no NaF influence on the bracket shear bond strength and even in low concentrations it prevented the development of areas of demineralization of white spot lesions.

Introdução O flúor é considerado um elemento chave no processo de remineralização do esmalte dentário. Objetivo Este estudo teve como objetivo avaliar a influência da solução tópica de fluoreto de sódio (NaF) na resistência ao cisalhamento da colagem de barquetes ortodônticos durante a formação de lesões de manchas brancas. Material e método Sessenta dentes bovinos foram divididos em três grupos (n=20). Grupo 1 (Controle) - Cisalhamento imediato; Grupo 2 - Cisalhamento após ciclagem de pH; Grupo 3 - Cisalhamento após ciclagem de pH e tratamento com solução de 0,4% de NaF (Ortho Gard, Colgate-Palmolive®). Os Grupos 2 e 3 sofreram ciclagem de pH com soluções de desmineralização e remineralização em pH de 4,3 e 7,0 respectivamente, com ciclos de desmineralização (6 horas) e remineralização (17 horas), durante 15 dias. Os corpos de prova foram submetidos ao teste de resistência de união ao cisalhamento e remanescente adesivo (IRA). Espécimes de cada grupo (n=3) foram analisados qualitativamente por microscopia eletrônica de varredura (MEV). O teste de Kruskal-Wallis foi utilizado para avaliar a resistência ao cisalhamento e o teste exato de Fisher para avaliação do IRA, adotando nível de significância de 5%. Resultado Os resultados não encontraram diferença significativa entre os três grupos quanto à força de cisalhamento (p=0,2679). Diferença significativa foi encontrada no IRA (p = 0,0199). A frequência de IRA 1 foi de 55% no grupo 1, 90% no grupo 2 e 80% no grupo 3. A análise em MEV mostrou diferença entre o esmalte e a área de colagem submetida ao cisalhamento. Grupo 2 apresentou alteração estrutural na superfície do esmalte adjacente à área de colagem, e o Grupo 3 apresentou esmalte com característica semelhante ao do Grupo 1 na área que foi submetida à ciclagem de pH e NaF. Conclusão Concluiu-se que não houve influência do flúor na resistência ao cisalhamento de braquetes. O uso de soluções fluoretadas, ainda que em baixa concentração, preveniu o aparecimento de áreas desmineralizadas e lesões de manchas brancas.

Influence of caries activity and number of saliva donors: mineral and microbiological responses in a microcosm biofilm model

Abstract Objective this study evaluated the mineral and microbiological response of biofilms originating from different types of saliva inoculum with distinct levels of caries activity. Methodology the biofilms grown over enamel specimens originated from saliva collected from a single donor or five donors with two distinct levels of caries activity (caries-active and caries-free) or from pooling saliva from ten donors (five caries-active and five caries-free). The percentage surface hardness change (%SHC) and microbiological counts served as outcome variables. Results the caries activity of donors did not affect the %SHC values. Inoculum from five donors compared to a single donor showed higher %SHC values (p=0.019). Higher lactobacilli counts were observed when saliva from caries-active donors was used as the inoculum (p=0.017). Pooled saliva from both caries activity levels showed higher mutans streptococci counts (p<0.017). Conclusion Overall, pooled saliva increased the mineral response of the derived biofilms, but all the inoculum conditions formed cariogenic biofilms and caries lesions independently of caries activity.

Biomimetic restoration and regeneration of dentin and cementum / 口腔疾病防治

@#Dental hard tissues lack the ability to self-heal. In dentin and cementum, hydroxyapatite (HA) can exist outside and/or inside collagen fibers. It is difficult to repair or regenerate HA with a highly ordered orientation in the presence of collagen fibers. At present, the biomimetic mineralization of dentin and cementum, mainly carried out by imitating its biological formation process and its physiological structure, can be divided into those originating from the fiber mineralization mechanism and those with HA as the main component. The materials used include natural materials such as demineralized dentin matrix (DDM) and calcined bovine hydroxyapatite (BHA), and synthetic materials such as polymer-induced liquid precursor (PILP) and synthetic HA. In the future, natural materials and synthetic materials should be combined for the restoration and regeneration of dentin and cementum by means of biomimetic mineralization of calcium phosphate released by remineralization solution-HA.

Association between demarcated enamel hypomineralization on second primary molars and dental caries in childhood / Associações entre hipomineralização demarcada de esmante nos segundos molares decíduos e cárie dentària na infância

ABSTRACT Hypomineralized Second Primary Molars (HSPM) is the name used to describe the presence of demarcated enamel hypomineralization in second primary molars. HSPM has been compared with Molar Incisor Hypomineralization (MIH) as regards its clinical appearance and consequences. The aim of this study was to investigate associations between HSPM and dental caries in childhood. It was a cross-sectional population-based study that included 216 children aged 4-6 years from public schools in Botelhos, Brazil. Children with all second primary molars erupted were eligible for participation. Clinical examination was performed by one calibrated examiner. HSPM was recorded according to modified European Academy of Paediatric Dentistry criteria. The main outcome was dental caries experience as indicated by the dmft index (%dmft>0) according to WHO criteria. Chi-square test and Logistic Regression Model were used to adjust the results for effects of covariates Among the 216 children examined, 22.2% presented HSPM. After adjustment for logistic regression, children with HSPM were found to have a 2.28 times greater chance of presenting dental caries. Our results reinforce the importance of HSPM in caries development in children, which should be considered by public health dentists in the process of planning actions aimed at this population.

RESUMO A hipomineralizacao de segundo molar deciduo (HSMD) é de-nominação utilizada para descrever a presenga de hipomineralização demarcada do esmalte nos segundos molares decídus. A HSMD foi comparada com a hipomineralização de molares e incisivos (HMI) no que diz respeito á aparencia e as conse-quencias clínicas. O objetivo deste estudo foi investigar asso-ciações entre HSMD e cárie na infáncia. Foi realiza um estudo transversal de base populacional, composto por 216 criangas de 4 a 6 anos de idade de escolas públicas de Botelhos, Brasil. As criangas com todos os segundos molares deciduos foram elegíveis para participação. O exame clínico foi realizado por um examinador calibrado. A HSMD foi registrada de acordo com os critérios modificados da European Academy of Paediatric Dentistry. O desfecho principal foi a experiencia de cárie dentària nos dentes deciduos conforme o índice ceo (% ceo> 0), segundo os critérios da OMS. Os testes de Qui-quadrado e o modelo de regressao logística foram utilizados para ajustar os resultados dos efeitos das covariáveis. Verificou-se que entre as 216 criangas examinadas, 22,2% apresentaram HSMD. Após o ajuste da regressao logística, as criangas com HSMD tiveram 2,28 vezes mais chances de apresentar cárie dentària. Nossos resultados reforgam a importáncia do HSMD no desenvolvimento da cárie em criangas, fato que deve ser considerado pelos dentistas de saúde pública no processo de planejamento de ações voltadas a essa população.

Uso de Biodentine para restaurar un molar permanente severamente afectado por la Hipomineralización de Molares e Incisivos / Use of Biodentine to restore a affected permanent molar severely by Molar-Incisor Hypomineralization / Uso de Biodentine para restaurar um molar permanente severamente afetado pela Hipomineralização de Molares e Incisivos

Resumen La Hipomineralización de Molares e Incisivos (HMI) es un defecto cualitativo del desarrollo del esmalte que afecta de uno a cuatro primeros molares permanentes, pudiendo estar asociado con los incisivos permanentes. Se estima que la prevalencia mundial es del 14.2%, siendo América del Sur la región con mayor prevalencia (18%). Clínicamente, los dientes afectados por la HMI presentan esmalte poroso y blando, acúmulo de biopelícula, lesiones de caries dental e hipersensibilidad. Los cambios estructurales y químicos pueden afectar los procedimientos restauradores. El objetivo del caso fue reportar el uso de un material bioactivo para la restauración de un primer molar permanente severamente afectado por la HMI. Paciente femenino de 7 años de edad que presenta en el diente 36 una lesión de caries activa cavitada, hipomineralización severa con fractura posteruptiva y exposición de dentina e hipersensibilidad. Luego de realizar la remoción selectiva del tejido cariado, se puso un substituto bioactivo de dentina a base de silicato tricálcico (Biodentine). Un mes después, el diente se restauró definitivamente con resina compuesta. Al seguimiento clínico de 12 meses la restauración presenta adecuada adaptación marginal, forma anatómica adecuada y sin evidencia de lesión de caries dental secundaria. Radiográficamente se observa adecuada adaptación de la restauración y sin cambios en el espacio del ligamento periodontal y región periapical. El uso de materiales bioactivos muestra ser una alternativa promisoria para la restauración de molares severamente afectados por la HMI.

Abstract Molar Incisor Hypomineralization (MIH) is a qualitative defect in the development of dental enamel that affects one to four first permanent molars and it might be associated with permanent incisors. Worldwide prevalence is estimated around 14.2%, being the highest in South America (18%). Clinical signs include porous and soft enamel, excessive biofilm formation, dental caries and hypersensitivity. Structural and chemical changes may affect restorative procedures. The objective of this case report was to describe the use of a bioactive restorative material on a severely-affected first permanent molar. A 7-year-old female patient presented with active dental caries lesion, severe hypomineralization with post-eruptive fracture, dentine exposure and hypersensitivity in tooth 36. After selective removal of carious tissue, a bioactive dentine substitute containing tricalcium silicate (Biodentine) was placed. One month later, the tooth was restored using resin composite. A follow-up exami- nation at 12 months showed good marginal adaptation, proper anatomical shape and no evidence of secondary caries. Radiographical examination showed correct adaptation of the restoration and normal space of the periodontal ligament and the periapical region. The use of bioactive materials seems to be a promising alternative for restoration of molars severely affected by MIH.

Resumo A Hipomineralização de Molares e Incisivos (HMI) é um defeito qualitativo do desenvolvimento do esmalte que afeta de um a quatro primeiros molares permanentes, podendo estar ou não associado aos incisivos permanentes. Estima-se que a prevalência mundial é de 14,2%, sendo a América do Sul a região com a maior prevalência (18%). Clinicamente, os dentes afetados pela HMI apresentam esmalte poroso e macio, acúmulo de biofilme, lesões de cárie dentária e hipersensibilidade. As alterações estruturais e químicas podem afetar os procedimentos restauradores. O objetivo deste caso foi reportar o uso de um material bioativo para a restauração de um primeiro molar permanente severamente afetado pela HMI. Paciente do sexo feminino de 7 anos de idade apresentava no dente 36 uma lesão de cárie cavitada e ativa, hipomineralização severa com fratura pós-irruptiva, com exposição de dentina e hipersensibilidade. Após a remoção seletiva do tecido cariado, colocou-se um substituto bioativo de dentina a base de silicato de cálcio (Biodentine). Um mês depois, o dente foi restaurado definitivamente com resina composta. No acompanhamento clínico de 12 meses, a restauração apresentava adaptação marginal e for- ma anatômica adequada e sem evidência de lesão de cárie secundária. Radiograficamente, observou-se adequada adaptação da restauração e sem alterações no espaço do ligamento periodontal e região periapical. O uso de materiais bioativos demonstram ser uma alternativa promissora para a restauração de molares severamente afetados pela HMI.