Effect of treatment time on performance of nano-encapsulated fluoride dentifrices for remineralization of initial carious lesions: an in vitro study.

The aim of this in vitro study was to evaluate the influence of treatment time on the remineralization performance of nanoencapsulated fluoride dentifrices on initial carious lesions. Ninety-six human enamel samples were allocated to eight groups (n = 12): 50% NanoF + 50% free NaF, 100% NanoF, 100% NaF (positive control), and placebo (negative control), using two different treatment times (one and five minutes) for each dentifrice tested. After the carious lesion induction, the specimens were submitted to a pH remineralizing cycling model for seven days. Surface microhardness was measured before and after carious lesion induction and after treatment. The percentage of surface remineralization was calculated for each study time. Data were analyzed using two-way ANOVA and ANOVA repeated-measures tests followed by the Bonferroni correction (p < 0.05). Remineralization differences were observed in the dentifrices analyzed according to the treatment time used. NanoF formulations with 50% (one-min treatment) and 100% (five-min treatment) promoted significant remineralization of enamel after the caries challenge when compared to the placebo dentifrice (p < 0.05). Thus, time was considered an important factor for the fluoride release system. Nanotechnology can be a promising system for caries remineralization as it makes fluoride available on the dental surface for a longer time.

O objetivo deste estudo in vitro foi de avaliar a influência do tempo de tratamento no desempenho de dentifrícios fluoretados nano-encapsulados na remineralização de lesões cariosas iniciais. Noventa e seis amostras de esmalte humano foram divididas em oito grupos (n = 12): 50% NanoF + 50% NaF livre, 100% NanoF, 100% NaF (controle positivo) e Placebo (controle negativo) com dois tempos diferentes (um e cinco minutos). Após a indução da lesão cariosa, os espécimes foram submetidos a um modelo de ciclagem de pH por sete dias. A microdureza superficial foi medida antes e após a indução da lesão cariosa e após o tratamento. O percentual de remineralização superficial foi calculado para cada tempo de estudo. Os dados foram analisados pelo ANOVA e ANOVA de medidas repetidas, seguida de Bonferroni (p <0,05). Diferenças de remineralização foram observadas nos dentifrícios de acordo com o tempo de tratamento utilizado. Formulações NanoF com 50% (tratamento de um minuto) e 100% (tratamento de cinco minutos) promoveram uma remineralização do esmalte, após o desafio cariogênico, quando comparado com o dentifrício placebo (p <0,05). Assim, o tempo foi considerado um fator importante para o sistema de liberação de flúor. A nanotecnologia pode ser um sistema promissor de remineralização da cárie, por disponibilizar o flúor por maior tempo na superfície dentária.

Effect of treatment time on performance of nano-encapsulated fluoride dentifrices for remineralization of initial carious lesions: an in vitro study / Efeito do tempo de tratamento no desempenho de dentifrícios de fluoreto nanoencapsulado para remineralização de lesões iniciais de cárie: um estudo in vitro

ABSTRACT The aim of this in vitro study was to evaluate the influence of treatment time on the remineralization performance of nanoencapsulated fluoride dentifrices on initial carious lesions. Ninety-six human enamel samples were allocated to eight groups (n = 12): 50% NanoF + 50% free NaF, 100% NanoF, 100% NaF (positive control), and placebo (negative control), using two different treatment times (one and five minutes) for each dentifrice tested. After the carious lesion induction, the specimens were submitted to a pH remineralizing cycling model for seven days. Surface microhardness was measured before and after carious lesion induction and after treatment. The percentage of surface remineralization was calculated for each study time. Data were analyzed using two-way ANOVA and ANOVA repeated-measures tests followed by the Bonferroni correction (p < 0.05). Remineralization differences were observed in the dentifrices analyzed according to the treatment time used. NanoF formulations with 50% (one-min treatment) and 100% (five-min treatment) promoted significant remineralization of enamel after the caries challenge when compared to the placebo dentifrice (p < 0.05). Thus, time was considered an important factor for the fluoride release system. Nanotechnology can be a promising system for caries remineralization as it makes fluoride available on the dental surface for a longer time.

RESUMO O objetivo deste estudo in vitro foi de avaliar a influencia do tempo de tratamento no desempenho de dentifrícios fluoretados nano-encapsulados na remineralizagao de lesoes cariosas iniciáis. Noventa e seis amostras de esmalte humano foram divididas em oito grupos (n = 12): 50% NanoF + 50% NaF livre, 100% NanoF, 100% NaF (controle positivo) e Placebo (controle negativo) com dois tempos diferentes (um e cinco minutos). Após a indugao da lesao cariosa, os espécimes foram submetidos a um modelo de ciclagem de pH por sete dias. A microdureza superficial foi medida antes e após a indugao da lesao cariosa e após o tratamento. O percentual de remineralizagao superficial foi calculado para cada tempo de estudo. Os dados foram analisados pelo ANOVA e ANOVA de medidas repetidas, seguida de Bonferroni (p <0,05). Diferengas de remineralizagao foram observadas nos dentifrícios de acordo com o tempo de tratamento utilizado. Formulagoes NanoF com 50% (tratamento de um minuto) e 100% (tratamento de cinco minutos) promoveram uma remineralizagao do esmalte, após o desafio cariogènico, quando comparado com o dentifricio placebo (p <0,05). Assim, o tempo foi considerado um fator importante para o sistema de liberagao de flúor. A nanotecnologia pode ser um sistema promissor de remineralizagao da cárie, por disponibilizar o flúor por maior tempo na superficie dentària.

Maxillary incisor enamel defects in individuals born with cleft lip/palate.

Cleft lip with or without cleft palate (CLP) is considered the most frequent congenital malformations of the head and neck, with cleft individuals exhibiting more chances of presenting abnormalities such as developmental defects of enamel (DDE). Matrix metallopeptidase 2 (MMP2) is a membrane-bound protein with collagen-degrading ability and has important roles in tooth formation and mineralization. The aim of this study was to evaluate the frequency, location, severity and extent of DDE found in the maxillary incisors for groups of individuals born with CLP, as well as understanding their relationship with the cleft side. Besides, this study addresses the hypothesis that DDE can be influenced by variation in the MMP2 genes (rs9923304). Individual samples, clinical history, intraoral photographs and panoramic radiographs were obtained from 233 patients under treatment at the Cleft Lip and Palate Service of the University Hospital Lauro Wanderley at the Federal University of Paraíba. Digital images were examined by the same evaluator using the Classification of Defects According to the Modified DDE Index, and then loaded into the Image Tool software, where two measurements were made: total area of the buccal surface (SA) and the area of the DDE (DA), obtaining the percentage of the surface area affected (%SAD) (ICC = 0.99). Genomic DNA was extracted from saliva samples from 124 participants. Genotyping was carried out using TaqMan chemistry for one marker in MMP2 (rs9923304). Statistical analyses were performed by The Jamovi Project software. The Shapiro-Wilk test was applied, followed by the Student's t-test and the Mann-Whitney test. Chi-square and Fisher's exact tests, and odds ratio (OR) with 95% confidence interval (CI) calculations were used to determine Hardy-Weinberg equilibrium and statistically significant differences with an alpha of 0.05. No significant differences in the prevalence and extent of enamel defects were found between male and female individuals born with CLP (p = 0.058256). The frequency of individuals presenting teeth with DDE, in relation to the cleft and non-cleft side, was statistically different (p <0.001; OR = 7.15, CI: 4.674> 7.151> 10.942). However, the averages of %SAD were similar (p = 0.18). The highest means of the %SAD were found in individuals with bilateral cleft lip with or without cleft palate (BCLP) when compared to individuals with unilateral cleft lip with or without cleft palate (UCLP), for the teeth inside (IA) and outside the cleft area (OA) (p <0.001). Regardless of the cleft side, individuals with BCLP were 7.85 times more likely to have more than one third of the tooth surface affected, showing more frequently defects in the three thirds (OA: p <0.001) (IA: p = 0.03), as well as a higher frequency of more than one type of defect (OA: p = 0.000358) (IA: p = 0.008016), whereas in UCLP, defects were isolated and restricted to only one third, more frequently, the incisal third (OA: p = 0.009) (IA: p = 0.001), with greater frequency of milder defects, such as demarcated (p = 0.02) and diffuse (p = 0.008) opacities. A higher frequency of the T allele, less common, was observed in the group of CLP individuals who had all the affected teeth or at least two teeth with %SAD greater than 20% (p = 0.019843). Our results suggest that MMP2 may have a role in the cases that presented DDE and genotyping rs9923304 could serve as the basis for a genomic approach to define risks for individuals born with CLP. Frequency and severity of DDE is strongly related to the CLP phenotype, since the highest values were found for BCLP. However, the extent of the DDE is independent of its relationship with the side of the cleft.