Evaluation of Nano TiO2 Modified Orthodontic Composite Effects on S. mutans Population and Enamel Demineralization in Fixed Orthodontic Patients; a Split Mouth Randomized Controlled Clinical Trial.

The high incidence of demineralization around orthodontic brackets has led to the development of preventive measures. Incorporation of antibacterial or remineralizing agents into orthodontic adhesives is an attractive method. This single-center, split-mouth, randomized controlled clinical trial was conducted to assess the effect of a modified composite containing TiO2 nanoparticles on the Streptococcus mutans population and to prevent demineralization around orthodontic brackets. Each participant was assigned a random sequence (AB or BA). During the bonding session, the control lateral incisor was bonded with a conventional composite and the contralateral incisor was bonded with a composite containing nano TiO2 particles (1%weight). The eligibility criteria included the presence of S. mutans in the dental plaque and absence of active caries, fractures or cracks. The S. mutans count in the dental plaque immediately around the brackets was evaluated at baseline and 1, 3, and 6 months after bonding. The specificity of the colonies was determined by PCR. The DIAGNOdent score was assessed at baseline and re-assessed every month up to the sixth month. Salivary samples were collected at T0, T1, and T3 to assess the amount of Ti released from the composite. The cytotoxicity of the modified composites was evaluated using an MTT assay. Participants, examiners, and data analyzers were blinded to the test and intervention groups. Forty-two patients ranging from 12 to 25 years were enrolled in this study. The amount of Ti released into saliva was insignificant and far below the toxic level. There was no significant difference between the S. mutans counts of the studied tooth S. mutans counts at any time point evaluated. DIAGNOdent scores on both sides increased significantly after the first month. However, this increase was higher on the test side (p < 0.001), and a significant difference of 2.6 scores remained throughout the study period. No severe adverse events were observed. Orthodontic composites containing TiO2 nanoparticles may prevent demineralization induced around brackets during orthodontic treatment. However, the antibacterial effects were not statistically significant.Registration: The protocol was registered with the IRCT.ir (IRCT20140215016582N6).

Effect of calcium fluoride nanoparticles in prevention of demineralization during orthodontic fixed appliance treatment: a randomized clinical trial.

BACKGROUND: White spot lesions (WSLs) are the most common complications of fixed appliance orthodontic treatment. OBJECTIVES: To evaluate the effectiveness of calcium fluoride nanoparticles-containing orthodontic primer (nCaF2-primer) in preventing the incidence of WSLs during orthodontic treatment. TRIAL DESIGN: Single-centre, double-blinded, split-mouth, randomized clinical trial. METHODS: The sample involved 31 orthodontic patients (≥12 years). Participants were recruited using a simple nonstratified randomization. Data collection, measurements, and analysis were performed blindly. Outcome measures included comparing the effect of nCaF2-primer with control primer (Transbond) regarding the degree of demineralization (DIAGNOdent pen), Streptococcus mutans (S. mutans) bacterial counting [real-time polymerase chain reaction device (PCR)], and WSLs incidence (pre- and post-operative photographs). The measurements were performed before bonding, 1, 3, and 6 months after bonding and after appliance removal. A two-way repeated measure analysis of variance test (for DIAGNOdent pen scores), and Wilcoxon signed-rank test (for the difference between bacterial counting and WSLs incidence) were used (P < 0.05). RESULTS: Thirty-one patients were recruited and randomized (mean age 17.9 ± 2.45 years). For the primary outcome (DIAGNOdent pen scores) and secondary outcome of S. mutans counting: 31 patients (310 teeth for each group) were included in scoring at T1 and T3, and 30 patients (300 teeth) were included at T6. While for the photographic scores, 26 patients were included after bracket bonding. The demineralization scores showed significant differences at all-time intervals within the 6 months after bracket bonding which was more noticeable after the first month. There was a significant difference in bacterial count between the two primer groups at the T1 only. Regarding photographic scores, there were no significant differences in the WSLs incidence between the two primers groups after brackets removal. No harm was detected during treatment, except the usual pain/gingival irritation. CONCLUSIONS: nCaF2-primer effectively decreased demineralization scores within the 6 months after bracket bonding. Moreover, it significantly reduced S. mutans colonization after the first month. However, the tested primer did not have an extra advantage in preventing WSLs development at the clinical level after appliance removal. TRIAL REGISTRATION: The trial was registered with ClinicalTrials.gov on 8 May 2021 (registration number: NCT04994314).

Effects of bovine milk osteopontin on in vitro enamel remineralization as a topical application prior to immersion in remineralizing solutions with/without fluoride.

The aim of the present study was to investigate the effects of bovine milk osteopontin (OPN) on enamel remineralization as a topical application prior to immersion in remineralizing solutions with/without fluoride. Bovine enamel blocks were demineralized then were divided into the following 3 groups: OPN (2.7 and 5.4 µM) solutions and deionized water (control). Each group was divided into 2 groups (remineralizing solution with or without 1 ppm of fluoride (F)). The specimens were analyzed by micro-CT and scanning electron microscope (SEM). The percentage of remineralization was higher in remineralization solution with than without F (p<0.05). The present results suggest that bovine milk OPN inhibits remineralization in solution without F, but 5.4 µM bovine milk OPN does not inhibit remineralization of the demineralized body using solution containing F by interrupting mineral deposition on the enamel surface.

Evaluation of tooth demineralization using laser-fluorescence in dental school patients undergoing orthodontic treatment: A clinical study.

BACKGROUND: Adverse effects can occur during orthodontic treatment. OBJECTIVE: To evaluate the relationship between prevalence and severity of enamel demineralization using a laser-fluorescence device, with length of orthodontic treatment time. METHOD: A cross-sectional study was conducted in 60 patients in a university orthodontic clinic. A clinical examination to establish demineralization at four sites on each tooth (premolar to premolar) was performed using the DIAGNOdent pen. The dependent variable was enamel demineralization, from which the prevalence (at least one affected site), extension (percentage of affected teeth) and adjusted average (average of the mean DIAGNOdent values per tooth) were calculated. The length of time for orthodontic treatment was determined in months. Various sociodemographic and clinical covariates were included. RESULTS: Average number of months under orthodontic treatment was 26.37 ± 24.81 months. Prevalence of enamel demineralization was 80.0%, its extension was 21.9% ± 17.2 and adjusted average of DIAGNOdent values was 6.09 ± 1.75. By quadrant, the teeth most affected were 14 (34.4%), 24 (25.0%), 31 (30.2%) and 44 (33.3%). No significant relationship (p> 0.05) was observed between enamel demineralization and length of time under orthodontic treatment. CONCLUSIONS: A high prevalence of dental demineralization was observed. In this sample, no relationship was observed between months under treatment and dental demineralization, or with other variables included in the study.

A novel method quantifying caries following orthodontic treatment.

This retrospective pilot study used a newly developed evaluation tool to assess the prevalence and incidence of White Spot Lesions (WSL) before and after multibracket appliance (MB) therapy. Digital photographs of 121 adolescent patients (63 ♂, 58 ♀) with metal brackets were analyzed retrospectively before and after MB therapy. The labial surfaces of anterior teeth, canine teeth, and premolars in the upper (UJ) and lower jaws (LJ) were evaluated using the Enamel Decalcification Index (EDI) by Banks and Richmond (Eur J Orthod, 16(1):19-25, 1994, levels 0-3) and a specially developed digitally scaled graticule with concentric circles to quantify the extent of WSL (in %). The statistical data analysis was based on crosstabulations and logistic regression. Before MB, 69.4% of the patients presented at least one WSL and 97.5% after, an increase of 28.1%. Before MB, 18.4% of the tooth surfaces (TS) showed an EDI level of 1-3. After MB, 51.8% of the TS featured WSL. 18.2% of the TS showed a WSL to the extent of ≥ 20-100% before and 52.3% after MB. The incidence in the UJ (71-79%) as well as the LJ (64-76%) was highest for the first and second premolars and lowest for LJ incisors (22-35%). The probability for developing a new distal WSL is higher than developing gingival, mesial or occlusal WSL. Labial MB therapy drastically increases the risk of developing WSL. We verified a concise quantification of the extent of labial WSL with the evaluation index.

Efficacy of sealants and bonding materials during fixed orthodontic treatment to prevent enamel demineralization: a systematic review and meta-analysis.

To analyse clinical studies investigating coating agents such as sealants and other bonding materials to prevent the initiation or inhibit the progress of white spot lesions (WSL) during orthodontic treatment with fixed appliances. Electronic databases (Pubmed, CENTRAL, EMBASE) were screened for studies. No language restrictions were applied. Study selection, data extraction and quality assessment were done in duplicate. Primary outcome included assessment of WSL with visual-tactile assessment and/or laser fluorescence measurements. Twenty-four studies with 1117 patients (age: 11-40 years) and 12,809 teeth were included. Overall, 34 different sealants or bonding materials were analysed. Fourteen studies analysed fluoride and 14 studies non-fluoride releasing materials. Meta-analysis for visual tactile assessment revealed that sealants significantly decreased the initiation of WSL compared to untreated control (RR [95%CI] = 0.70 [0.53; 0.93]; very low level of evidence). Materials releasing fluoride did not decrease initiation of WSL compared to those with no fluoride release (RR [95%CI] = 0.84 [0.70; 1.01]; very low level of evidence). For laser fluorescence measurements no meta-analysis could be performed. The use of sealants seems to be effective in preventing the initiation of post-orthodontic WSL. Furthermore, there is no evidence supporting that fluoride-releasing sealants or bonding materials are more effective than those without fluoride release. No gold standard prevention strategy to prevent WSL during treatment with fixed orthodontic appliances has been established yet. However, based on only a limited number of studies the use of sealants seems to be effective in preventing the initiation of post-orthodontic WSL.

Análise físico-química de balas duras e mastigáveis e o seu efeito desmineralizante em esmalte bovino / Physico-chemical analysis of hard and soft candies and their demineralizing effect in bovine enamel

Objetivo: avaliar o potencial cariogênico de balas duras e mastigáveis e seu potencial desmineralizante em esmalte bovino. Métodos: foram selecionadas 30 balas de diferentes marcas, divididas em balas duras (n=11), Tic Tac®, Halls® e IceKiss®, e balas mastigáveis (n=19), Lílith®, Azedinha®, Mentos Rainbow® e Dori Gomets®. As balas foram dissolvidas em água destilada (1:10) e foram avaliados pH, acidez titulável (ATT) e presença de sólidos solúveis totais (SST/°Brix). Na ciclagem erosiva, 40 espécimes de esmalte bovino foram divididos em quatro grupos (n=10): GCN ­ saliva artificial; GCP ­ ácido clorídrico; GT1 ­ solução da bala Lílith® maçã verde; GT2 ­ solução da bala IceKiss® extraforte. O desafio erosivo foi realizado por 2 minutos, 4x/dia, segui-do de 2 horas de imersão em saliva artificial durante cinco dias. Resultados: os valores de pH para as balas duras e mastigáveis variaram de 2,88 a 5,53 e de 2,73 a 4,16, respectivamente. ATT em pH 5,5 variou de 0,07 mL a 39,40 mL de NaOH 0,1 N, para as balas duras, e de 1,53 mL a 35,83 mL, para balas mastigáveis. ATT em pH 7,0 variou de 0,2 mL a 49,13 mL de NaOH, para balas duras, e de 2,37 mL a 49,97 mL, para as mastigáveis. O conteúdo de SST de todas as balas duras foi superior a 8,5°Brix, já entre as mastigáveis variou de 5,3 a 8,83°Brix. O GCP apresentou maior desmineralização que GCN e GT2 (p<0,05). Conclusão: a maioria das balas duras e mastigáveis dissolvidas em água destilada mostraram-se potencialmente erosivas e cariogênicas.(AU)

Objective: evaluate the cariogenic potential of hard and soft candies and their demineralizing potential in bovine enamel. Methods: 30 candies of different brands were selected, divided into hard candies (n=11): Tic Tac®, Halls® and IceKiss® and soft candies (n=19): Lílith®, Azedinha®, Mentos Rainbow® and Dori Gomets®. The candies were dissolved in distilled water (1:10) and pH, titratable acidity (TT) and presence of total soluble solids (SST/°Brix) were evaluated. In erosive cycling, 40 specimens of bovine enamel were divided into four groups (n=10): GCN - artificial saliva; GCP - hydrochloric acid; GT1 - Lilith® apple green candy solution; GT2 - IceKiss® Extra Strong candy Solution. The erosive challenge was performed for 2 minutes, 4X/day, followed by 2 hours of immersion in artificial saliva for five days. Results: pH values for hard and soft candies ranged from 2.88 to 5.53 and 2.73 to 4, respectively. ATT at pH 5.5 varied from 0.07 mL to 39.40 mL of 0.1 N NaOH for hard candies and 1.53 mL to 35.83 mL for soft candies. ATT at pH 7,0 varied from 0.2 mL to 49.13 mL of 0.1 N NaOH for hard candies and from 2.37 mL to 49.97 mL for soft candies. The content of SST of all hard candies was higher than 8.5 °Brix and for soft candies, varied between 5.3 to 8.83 °Brix. The GCP group showed greater demineralization than GCN and GT2 (p<0.05). Conclusion: most hard and soft candies dissolved in distilled water were potentially erosive and cariogenic.(AU)

Assessment of the Effectiveness of Different Fluoride-releasing Bonding Agents on Prevention of Enamel Demineralization around Orthodontic Bracket: An In Vitro Study.

AIM: The aim of the current research was to evaluate the efficacy of different fluoride-releasing bonding products in preventing enamel demineralization around orthodontic brackets by using a scanning electron microscope (SEM). MATERIALS AND METHODS: This research was performed using 80 healthy human premolar teeth that were extracted in course of orthodontic therapy. Until use, the sample premolars were subjected to storage in 0.1% thymol. Each premolar was thereafter cleansed with pumice for 10 seconds. Stainless steel brackets for premolars were employed. The 80 samples were allocated at random to one of the four groups (20 in each) as follows: Group I, control; group II, Transbond Plus color change adhesive; group III, GC Fuji Ortho LC; and group IV, Vitremer. An hour following bonding, all samples were subjected to pH cycling at a temperature of 37°C for a 14-day period. The premolar teeth were assessed below SEM. Analysis was performed with the one-way analysis of variance. Statistical significance was set at a p-value less than 0.05. RESULTS: The extreme area of demineralization was abridged by the use of Transbond™ Plus color change adhesive (108.19 ± 0.68), trailed by GC Fuji Ortho LC (119.24 ± 0.37) use, Vitremer (121.56 ± 0.92) as well as the control group (141.88 ± 1.09) in that order. And there was a statistically significant difference found between the groups (p <0.001). Tukey's honestly significant difference (HSD) was employed in an overall comparison of mean areas of enamel demineralization, which depicted that differences were significant statistically with the exception of group III and group IV. CONCLUSION: The current research came to a conclusion that the Transbond Plus color change adhesive group was more potent in significant inhibition of demineralization areas in comparison to GC Fuji Ortho LC group and Vitremer group. CLINICAL SIGNIFICANCE: In course of fixed orthodontic therapy, demineralization of enamel is an inherent occurrence. Multiple approaches are being continually developed to avoid the formation of white spot lesions (WSLs) that compromise esthetics and cause deprived remineralization that enhances the menace of dental caries. Bonding agents that can release fluorides are thus considered highly efficacious.

Effects of adhesive flash-free brackets on enamel demineralization and periodontal status.

OBJECTIVES: To evaluate the effects of adhesive precoated (APC) flash-free brackets on enamel demineralization and periodontal status in patients during fixed orthodontic treatment. MATERIALS AND METHODS: Thirty patients, age 12 to 18 years, who had Angle Class I or Class II malocclusion with mild to moderate crowding in the permanent dentition were selected for this study. APC flash-free and conventional ceramic brackets were bonded for a split-mouth study design. The quadrant allocation was randomized. Demineralization records were obtained immediately after bonding (T0), 1 month after bonding (T1), and 6 months after bonding (T2). Clinical periodontal measurements, including gingival index, plaque index, and bleeding upon probing, were obtained before bonding (T0) and at the same time points (T1 and T2). Data were analyzed using Mann-Whitney U and Friedman tests to compare parameters between groups and times. RESULTS: Demineralization values decreased on most sides of the brackets for both groups between T0 and T1. In the conventional group, there was significantly higher demineralization on more sides compared with flash-free brackets between T1 and T2. With one exception, the decreased values were found in the incisal/occlusal sides of all brackets at T2. All periodontal parameters showed significant increases after 6 months of treatment in both groups. Intergroup comparison showed no significant differences in demineralization or periodontal measurements at any of the time points. CONCLUSIONS: The effects of APC flash-free and conventional brackets on enamel demineralization and periodontal health did not differ from each other.

ORAL HYGIENE IN CHILDREN WITH DISTURBANCES IN TOOTH FORMATION WHO WERE AFFECTED AS A CONSEQUENCE OF THE ChNPP ACCIDENT. / STAN GIGIIeNY POROZhNYNY ROTA U DITEI Z PORUShENNIaMY FORMUVANNIa ZUBIV, POSTRAZhDALYKh VNASLIDOK AVARIÏ NA ChAES.

OBJECTIVE: evaluation of oral hygiene to enhance the prophylaxis of complications specifically of dental caries inchildren with disturbances in tooth formation (DTF) who live on radiologically contaminated territories after theChornobyl NPP (ChNPP) accident. MATERIALS AND METHODS: Children aged 6-14 years (n = 1470) with DTF were the study subjects examined in 2012-2016. Among them there were (n = 528) residents of the zones III and IV of radiological contamination after theChNPP accident with 137Cs soil contamination density 1-15 Ci/km2. The effective radiation dose in them was notexceeding 1 mSv/year. The Green-Vermillion and Silness-Loe oral hygiene indices were assesses within clinicalexamination methods. RESULTS: The worth oral hygiene was revealed in children having got the DTF, compensated chronic diseases oforgans and systems, and in those with burdened radiation history. The Green-Vermilion and Silness-Loe indices were1.7 ± 0.51 and 1.65 ± 0.46 respectively. CONCLUSIONS: A significant deterioration in oral hygiene confirmed by the highest values of the Green-Vermillion index (1.7 ± 0.51; p < 0.001 - «unsatisfactory oral hygiene¼ criterion) and Silness-Loe index (1.65 ± 0.46; p < 0.001 -«poor oral hygiene¼ criterion) was found in children with DTF aged 6-14 years being residents of contaminated areasas a result of the Chernobyl accident. The revealed deterioration may be due to a set of negative factors, includingthe impact of ionizing radiation in low doses and peculiarities of social status. Results of the questioning of surveyed pediatric contingents both having got an DTF and with no defects of the hard tissues of teeth indicate aninsufficient level of knowledge and skills in hygienic care of oral cavity regardless of the area of residence.Development of a set of measures to prevent the DTF complications in children should be carried out taking intoaccount the state of oral hygiene, level of knowledge and skills in oral care, and include the use of hygiene products, namely toothpastes and anti-caries mouthwashes.

Establishment of microcosm biofilm models that reproduce a cariogenic diet intake.

Biofilms were developed from human saliva on bovine enamel discs in four experimental conditions to investigate dental caries development: feast and famine (M1), abundance and scarcity (M2), three meals daily (M3), and three meals plus two snacks daily (M4). The main difference between these models was the diet for microbial growth. The evaluations included verifying the pH of the spent culture media and analyzing the enamel discs for demineralization (microhardness and roughness) and biofilms (biomass, viable populations of mutans streptococci, and total microbiota). Two major behaviors were observed: M1 and M2 promoted an acidic environment, while M3 and M4 maintained pH values closer to neutral. The demineralization process was slower in the neutral groups but more pronounced in M3, while a greater increase in microbiota and biomass was observed over time for both neutral groups. Thus, the M3 model was better at mimicking the oral environment that leads to demineralization.

Impact of self-assembling peptides in remineralisation of artificial early enamel lesions adjacent to orthodontic brackets.

Enamel demineralisation can occur as a side effect during orthodontic treatment with fixed appliances. This study aimed to evaluate the efficacy of the self-assembling peptide P11-4 for remineralisation combined with fluorides, compared to application of fluoride varnish alone. De- and remineralisation was assessed by Quantitative light-induced fluorescence (QLF). Orthodontic brackets were bonded on 108 human enamel samples and white spot lesions were created. The samples were allocated randomly into three groups: Group I received no treatment, group II had a single application of fluoride varnish (22,600 ppm), and group III was treated with P11-4 following a single application of fluoride varnish. Quantitative light-induced fluorescence (QLF) measurements were performed at baseline, after demineralisation and after storage in remineralisation solution for 7 and 30 days. Non-parametric tests (Kruskal-Wallis test and Friedman test) were used for further analysis. After demineralisation, all samples showed a median ΔF -9.38% ± 2.79. After 30 days median ΔF values were as followed: group I = -9.04% ± 2.51, group II = -7.89 ± 2.07, group III = -6.08% ± 2.79). The median ΔF values differed significantly between all groups at all investigation times (p < 0.00001). Application of P11-4 with fluoride varnish was superior to the use of fluorides alone for remineralisation of enamel adjacent to brackets.

Demineralization of tooth enamel following radiation therapy; An in vitro microstructure and microhardness analysis.

OBJECTIVE: The objective of this study is to evaluate the effects of radiotherapy doses on mineral density and percentage mineral volume of human permanent tooth enamel. MATERIALS AND METHODS: Synchrotron radiation Xray microcomputed tomography (SRµCT) and microhardness testing were carried out on 8 and 20 tooth samples, respectively. Enamel mineral density was derived from SRµCT technique using ImageJ software. Microhardness samples were subjected to Vickers indentations followed by calculation of microhardness and percentage mineral volume values using respective mathematical measures. Data were analyzed using paired t-test at a significance level of 5%. Qualitative analysis of the enamel microstructure was done with two-dimensional projection images and scanned electron micrographs using µCT and field emission scanning electron microscopy, respectively. RESULTS: Vickers microhardness and SRµCT techniques showed a decrease in microhardness and an increase in mineral density, respectively, in postirradiated samples. These changes were related to mineral density variation and alteration of hydroxyapatite crystal lattice in enamel surface. Enamel microstructure showed key features such as microporosities and loss of smooth homogeneous surface. These indicate tribological loss and delamination of enamel which might lead to radiation caries. CONCLUSIONS: Tooth surface loss might be a major contributing factor for radiation caries in head-and-neck cancer patients prescribed to radiotherapy. Such direct effects of radiotherapy cause enamel abrasion, delamination, and damage to the dentinoenamel junction. Suitable measures should, therefore, be worked out to protect nontarget oral tissues such as teeth while delivering effective dosages to target regions.

Oral manifestations of Alagille syndrome.

Alagille syndrome (AGS) is a multisystem disorder classically involving liver and heart failure, characteristic vertebral and facial features and ocular abnormalities. AGS is caused by heterozygous mutations in JAG1 or NOTCH2, with variable phenotype penetrance. We report two cases of AGS in children with tooth defects characterised by green discolouration and hypomineralisation. The role of hyperbilirubinaemia (HB) in this atypical colour, a classical feature of AGS, has been well described. However, it does not totally explain the dental phenotype. As JAG1 and NOTCH2 mutations can affect bone development and considering common physiological pathways between bone and tooth mineralisation, both mutations could participate in this unusual dental phenotype. The role of HB and genetics in the development of the dental phenotype of AGS is discussed in two prototypical cases. Future research should focus on the underlying genetic component of tooth abnormalities.

Near-Surface Studies of the Changes to the Structure and Mechanical Properties of Human Enamel under the Action of Fluoride Varnish Containing CPP-ACP Compound.

Changes to the features of the enamel surface submitted to induced demineralisation and subsequent remineralisation were studied. The in vitro examination was conducted on polished slices of human molar teeth, divided in four groups: the untreated control (n = 20), challenged by a demineralisation with orthophosphoric acid (H3PO4) (n = 20), and challenged by a demineralisation following remineralisation with fluoride (F) varnish containing casein phosphopeptides (CPP) and amorphous calcium phosphate (ACP) compounds (n = 20). The specimens' enamel surfaces were subjected to analysis of structure, molecular arrangement, mechanical features, chemical composition, and crystalline organization of apatite crystals. Specimens treated with acid showed a significant decrease in crystallinity, calcium, and phosphorus levels as well as mechanical parameters, with an increase in enamel surface roughness and degree of carbonates when compared to the control group. Treatment with fluoride CPP-ACP varnish provided great improvements in enamel arrangement, as the destroyed hydroxyapatite structure was largely rebuilt and the resulting enamel surface was characterised by greater regularity, higher molecular and structural organisation, and a smoother surface compared to the demineralised one. In conclusion, this in vitro study showed that fluoride CPP-ACP varnish, by improving enamel hardness and initiating the deposition of a new crystal layer, can be an effective remineralising agent for the treatment of damaged enamel.

Fatores ambientais e variações genéticas nos genes AMBN, ENAM, KLK4, IRF6, TFGα em pacientes com hipomineralização molar incisivo / Environmental factors and genetic variations in the AMBN, ENAM, KLK4, IRF6, TFGα in patients with incisor molar hypomineralization

Trata-se de uma tese composta por quatro estudos, com o objetivo de avaliar possíveis fatores etiológicos (ambientais e genéticos) associados a presença de Hipomineralização Molar Incisivo (HMI) através de (a) : um estudo observacional transversal para verificar a prevalência de HMI na amostra estudada, junto com uma revisão bibliográfica da prevalência desta condição na população brasileira (objetivo-I); associação de fatores ambientais (durante o período gestacional e nos primeiros anos de vida) relacionados à presença de HMI e a influência destes fatores com a gravidade dessa condição (objetivo-II); associação dos polimorfismos de único nucletídeo (SNPs) localizados nos genes ameloblastina (AMBN), enamelina (ENAM) e calecreína com HMI, além da possível susceptibilidade dos SNPS com à cárie dentária (objetivo-III) e a interação entre fatores ambientais e as variações genéticas nos SNPs localizados nos genes fator 6 regulator de interferon (IRF6) e fator de crescimento transformador alfa (TGFα) estudados em amostras no Rio de Janeiro, Curitiba e turca (Istambul) (objetivo-IV). As coletas de dados do presente estudo foram realizadas em duas etapas: clínica e laboratorial. Os resultados encontrados foram: (I) uma alta heterogeneidade entre os estudos (Q = 52,81, p < 0.01, I2 = 98) com a prevalência final de HMI de 13.48% na população barasileira; (II) as intercorrências na gestação e o uso de medicamentos na primeira infância tiveram uma associação significativa com a presença de HMI (OR = 3,01; 95% CI = 1,74- 8,42; p= 0,014; OR = 3,55; 95% CI = 1,35-10,57; p = 0,019 ), entretanto esses fatores não influenciaram a gravidade dessa condição (p>0,05); (III) houve um resultado significativo no SNP rs2235091 localizado no gene KLK4 com a HMI (p<0,001), e os polimorfismos rs4694075 (AMBN) e rs3796704 (ENAM) mostraram associação com a cárie dentária (p<0.05); (IV) a amostra do Rio de Janeiro apresentou uma interação entre os SNPs rs1523305 (TGFα) e rs642961 (IRF6) (p = 0,03) e entre rs2073487 (IRF6) e rs2902345 (TGFα) (p = 0,04). Além disso, no estudo de Istambul houve uma associação entre o SNP rs930655 (TGFα) com todos os marcadores do gene IRF6 (p<0,05). Em relação ao uso de medicamentos nos primeiros anos de vida houve uma associação com os genes TGFα e IRF6 nas amostras de Curitiba e do Rio de Janeiro (p<0,05). Conclui-se que; (I) a prevalência de HMI é de 13.48% na população brasileira; (II) existe uma relação entre a presença de HMI com complicações que ocorrem durante a gestação (uso de medicamentos) e nos primeiros anos de vida da criança, entretanto esse fatores não influenciaram na gravidade dessa condição; (III) os genes que atuam na formação do esmalte são capazes de influenciar tanto no desenvolvimento da HMI como podem estar associados à cárie dentária e (IV) os polimorfismos localizados nos genes IRF6 e TGFα estão relacionados com o desenvolvimento da HMI. Além disso, o uso de medicamentos nos primeiros anos de vida podem potencializar o desenvolvimento da HMI. (AU)

It is a thesis composed of four studies, with the main to evaluate possible etiological factors (environmental and genetic variation) associated with the presence of MIH in the Brazilian population through (e); (objective-I); a cross-sectional observational study, with a bibliographic review of the prevalence of MIH in Brazil (objective-I); to determine of environmental factors (during in the pregany period and childhood) associated with the presence of MIH, and to evaluate the influence of these factors with the MIH severity (objective-II); associations of single nucleotide polymorphism (SNPs) presentin the genes ameloblastin (AMBN), enamelin (ENAM) and kalekrein (KLK-4) with MIH, in addition to the possible susceptibility of this genes to dental caries (objective-III); and interaction of environmetal factors and to determine the influence of genes interferon regulatory factor 6 (IRF6) and transforming growth factor alpha (TGFα) with MIH in a Brazilian (Rio de Janeiro e Curitiba) and Turkish (Istanbul) population (objective-IV). Data collections of the present study were carried out in two stages: clinical and laboratory.The results found were: (I) a high heterogeneity among the studies (Q = 52.81, p<0.01, I2 = 98) with a final prevalence of 13.48% na Brazilian population; (II) an association between intercurrences during pregnancy and child taking medications with the presence of MIH (OR = 3.55; 95% C.I = 1.35-10.57, p= 0.014; OR = 3.01; 95% C.I = 1.74- 8.42, p= 0.019, respectively), however these factors did not influence the severity of MIH (p>0.05); (III) there was an association between the variant alleles of polymorphisms rs2235091 in the KLK4 gene (p≤0.01) with the presence of MIH and the SNPs rs4694075 in AMBN and rs3796704 in ENAM presents association with dental caries (p<0.05); (IV) that the study from Rio de Janeiro showed a statistical evidence of interaction between TGFA rs1523305 and IRF6 rs642961 (p=0.03) and between genes IRF6 rs2073487 and TGFA rs2902345 (p=0.04). Significant results were found for the study from Istanbul between TGFα rs930655 and all IRF6 markers (p<0.05). Also, there was found statistical evidence for interaction of the SNPs in IRF6 and TGFα genes and medication taking from Curitiba and Rio de Janeiro studies (p<0.05). In summary; (I) the prevalence of MIH is 13.48% in the Brazilian population; (II) there is a relationship between complication that occur during pregnancy and in the child's first years of life with the presence of MIH, however these factors do not influence the severity of this condition; (III) the genes that acting in the enamel formation may influence the development of MIH and them, may be associated with dental caries; (IV) the polymorphisms located in the IRF6 and TGFα genes play a role in the development of MIH in different populations and that these genes may interacting with the medication taken in the first years of life, pontecialising the presence of MIH. (AU)

Hipomineralización incisivo molar y factores etiológicos ambientales. Revisión de la literatura / Molar incisor hypomineralization and etiological environmental factors. Review of the literature

La etiología de la hipomineralización incisivo-molar (HIM) aún no está totalmente definida, por lo que el objetivo del presente artículo fue hacer una revisión de la literatura de los posibles factores etiológicos asociados. Se realizó una búsqueda inicial en las bases de datos Elsevier, EBSCO, PubMed y Medline usando las siguientes palabras clave: molar incisor hypomineralisation, hypoplasia, dental enamel defects epidemiology, etiology. Se incluyeron artículos en inglés y español, estudios epidemiológicos de casos y controles de HIM, descripción del método de diagnóstico y registro, y descripción del factor asociado, publicados entre 1987 y 2018. Tomando en consideración 40 artículos que cumplían con los criterios de búsqueda. Se dividieron los factores etiológicos encontrados en tres etapas: prenatal, perinatal y posnatal. La causa exacta aún no está del todo definida, pero con base en los estudios tenemos indicios que nos podrían ayudar a prevenir este tipo de defectos. Sin embargo, son necesarios más estudios longitudinales para poder determinar la etiología exacta de esta alteración en la formación dental, mientras tanto los médicos pediatras y odontopediatras deben estar conscientes que el manejo temprano y adecuado de estas del HIM es importante. (AU)

The etiology of molar incisor hypomineralization (MIH) is not yet fully defined, therefore the objective of this article was to review the literature on the possible associated etiological factors. An initial search was performed in the Elsevier, EBSCO, PubMed and Medline databases using the following keywords: molar incisor hypomineralization, hypoplasia, dental enamel defects epidemiology, and etiology. Articles in English and Spanish were included as well as epidemiological studies of cases and controls of MIH, descriptions of the method of diagnosis and registration, and descriptions of associated factors published between 1987 and 2018. Forty articles met the search criteria. The etiological factors found were divided into three stages: prenatal, perinatal and postnatal. While the cause of MIH has yet to be fully defined, the studies available describe indications to help prevent this type of defects. Nonetheless, more longitudinal studies are necessary to determine the exact etiology of this alteration, and pediatricians and pediatric dentists should take into account the importance of early, adequate management of MIH. (AU)

Resin-modified glass ionomer cement vs composite for orthodontic bonding: A multicenter, single-blind, randomized controlled trial.

INTRODUCTION: In this study, we aimed to compare the incidence of new demineralized lesions and bond failures between 2 groups of participants wearing fixed orthodontic appliances bonded with either light-cured resin-modified glass ionomer cement or light-cured composite. METHODS: This trial was a multicenter (6 centers: 2 teaching hospitals, 4 specialist orthodontic practices), single-blinded, randomized controlled trial with 2 parallel groups. Patients aged 11 years or older, in the permanent dentition, and about to start fixed orthodontic treatment in these 6 centers were randomly allocated to have either resin-modified glass ionomer cement or light-cured composite for bonding brackets, forward of the first molars. Pretreatment and day-of-debond digital photographic images were taken of the teeth and assessed by up to 5 clinical and 3 lay assessors for the presence or absence of new demineralized lesions and the esthetic impact. The assessors were masked as to group allocation. RESULTS: We randomized 210 participants, and 197 completed the trial. There were 173 with complete before-and after-digital images of the teeth. The incidence of new demineralized lesions was 24%; but when the esthetic impact was taken into account, this was considerably lower (9%). There was no statistically significant difference between the bracket adhesives in the numbers with at least 1 new demineralized lesion (risk ratio,1.25; 95% confidence interval, 0.74-2.13; P = 0.403) or first-time bracket failure (risk ratio,0.88; 95% confidence interval, 0.67-1.16; P = 0.35). There were no adverse effects. CONCLUSIONS: There is no evidence that the use of resin modified glass ionomer cement over light-cured composite for bonding brackets reduces the incidence of new demineralized lesions or bond failures. There might be other reasons for using resin modified glass ionomer cement. REGISTRATION: This trial was registered at ClinicalTrials.govNCT01925924. PROTOCOL: The protocol is available from the corresponding author on request.

Optical evaluation of enamel white spot lesions around orthodontic brackets using swept-source optical coherence tomography (SS-OCT): An in vitro study.

The aim of this study was to evaluate in vitro detection of enamel white spot lesions around orthodontic brackets using swept-source optical coherence tomography (SS-OCT). Twenty-four clear orthodontic brackets were bonded onto the enamel surface of bovine incisor specimens using three types of orthodontic resin adhesives: non-fluoridated, fluoridated, and fluoridated light cured. The specimens were subjected to artificial demineralization. SS-OCT images were captured before demineralization and at 24 h and 1 week after demineralization. Lesion depth (LD) was measured and analyzed using Image J software. Results revealed significant increases in LD with time in all three groups. LDs were, however, significantly smaller in the fluoridated adhesive groups than in the non-fluoridated group. In addition, SS-OCT was validated for the detection of micro-leakage and white spot lesions beneath and around the orthodontic brackets.

Cariogenicity of a Milk-Based Drink Used as a Dietary Supplement for Older Adults Using a Root Caries Experimental Model.

The aim of this study was to evaluate the cariogenicity of a milk-based drink intended for older adults that was used as part of a governmental initiative in Chile to improve their nutritional conditions. This drink contains a high concentration of sugars, which can contribute to root caries development. To test this hypothesis, an experimental biofilm/caries model was used. Dentin slabs were used to grow biofilms of Streptococcus mutans UA159. Slabs/biofilms were exposed 3× per day to bovine milk with different fat content, the milk-based drink, and the milk-based drink supplemented with 10 g of sucrose added per serving. Slabs exposed to 10% sucrose or 0.9% NaCl were used as positive and negative controls, respectively. Biofilms were analyzed for bacterial counts and acidogenicity. Dentin demineralization was estimated by the loss of surface microhardness and integrated mineral loss. Results were compared by analysis of variance and Tukey's test. The milk-based drink showed higher acidogenicity than milk with its entire (whole) or reduced total fat content (skim). The milk-based drink supplemented with -sucrose had similar acidogenicity as the 10% sucrose positive control (p = 0.506). Whole milk exposure elicited lower bacterial counts than the positive control, the milk-based drink, and the milk-based drink supplemented with sucrose (p = 0.002; 0.006 and 0.014 respectively). Although skim milk induced higher demineralization than whole milk, both milk types produced lower demineralization than the milk-based drink. Regarding integrated mineral loss, demineralization induced by the milk-based drink and the milk-based drink supplemented with sucrose was similar to that induced by the positive control and skim milk (p > 0.05). Sugar-containing milk-based drinks used as dietary supplements for older adults may be highly cariogenic and could represent a potential risk for root caries.