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.

Effect of orthodontic traction on the microstructure of dental enamel / 南方医科大学学报

OBJECTIVE@#To investigate the effect of orthodontic traction on the microstructure of dental enamel.@*METHODS@#Forty-eight isolated premolars were randomly divided into 6 groups (=8), including Group A (blank control group), in which the teeth were bonded with the orthodontic brackets without any loading force; Groups B1, B2, and B3 where the teeth were bonded with the orthodontic brackets using clinical adhesives and loaded with 50 g force for 6 months, 200 g force for 6 months, and 200 g force for 1 month, respectively; and Groups C1 and C2, where the teeth were bonded with straight wire brackets using light curing bonding and chemical curing bonding techniques, respectively. All the teeth were embedded with non-decalcified epoxy resin. Scanning electron microscope (SEM), atomic force microscope (AFM), and energy spectrometer (EDS) were used to analyze interface morphology and elemental composition of the teeth sliced with a hard tissue microtome.@*RESULTS@#Compared with those in Group A, the teeth in the other 5 groups showed increased adhesive residue index with microcracks and void structures on the enamel surface under SEM; AFM revealed microcracks on the enamel surface with angles to the grinding direction. A larger loading force on the bracket resulted in more microcracks on the enamel interface. The interface roughness differed significantly between Groups A and C2, and the peak-to-valley distance differed significantly between Groups A, C, and C2.@*CONCLUSIONS@#Orthodontic traction can cause changes in the microstructure of normal dental enamel.

The use of epigallocatechin gallate prevents white spot lesions during orthodontic treatment with fixed appliances / 中国组织工程研究

BACKGROUND: Plenty of studies have already proved the effective usage of epigallocatechin gallate (EGCG) in clinical treatment. However, no current research has focused on the application of EGCG in preventing white spot lesions (WSLs) during orthodontics treatment with fixed appliances. OBJECTIVE: To study the value of EGCG in the prevention of WSLs during orthodontic treatment with fixed appliances. METHODS: In total 50 patients undergoing orthodontic treatment with fixed appliances were carefully screened and enrolled. Split-mouth design was adopted: the right side of teeth received experimental adhesive (1 g/L EGCG + Adper™ Single Bond 2); the left side of teeth acted as control. All the other clinical procedures and materials used were same. The enamel demineralization index (EDI) and the WSLs prevalence of targeted teeth (16, 11, 46, 26, 31, and 36) were detected at 3, 6, and 12 months during the treatment, and the percentage of bracket bonding failure was calculated for each group. The study protocol was implemented in line with the relevant ethical requirements of Liuzhou People’s Hospital. Patients and their guardians were fully informed of the whole trial procedures. RESULTS AND CONCLUSION: In this trial, the percentage of bracket bonding failure was significantly different between the EGCG group and control group (P > 0.05). After 3 months of treatment, the values of WSLs and EDI had no significant difference between the EGCG group and control group (P > 0.05). However, after 6 months and 12 months treatment, the EGCG group manifested significantly lower WSL and EDI values than the control group (P < 0.05). Therefore, addition of the adhesive containing 1 g/L EGCG has a considerable effect in preventing enamel demineralization and the occurrence of WSLs without influencing the enamel bonding strength, and it has a long-time effect which deserves the clinical expansion.

A comparison of antibacterial inhibitory effect on Streptococcus mutans and tensile strength between chitosan-based bonding adhesives and commercial products

Background: Adhesive bonding is the material used to attach a bracket to the enamel surface of the tooth. Streptococcus mutans contributes to enamel demineralization during orthodontic treatment. Objectives: To analyze the antimicrobial inhibitory effect of Streptococcus mutans bacteria and tensile strength of chitosan and CaCO3-based adhesive bonding material. Materials and Methods: The investigation constituted laboratory experimental research featuring analytical observation and a random sampling method. The antibacterial inhibitory effect of chitosan and CaCO3-based adhesive bonding against Streptococcus mutans involved six groups: two control groups using commercial light cure and self-cure adhesive bonding products and four groups using adhesive bonding consisting of 75% CaCO3 + 17.6% Bis-GMA + 22.4% MMA with various percentages of chitosan composition (A1: 25%, A2: 50%, A3: 75%, and A4: 100%) each group consisting of two samples (n = 12). A diametric test was conducted consisting of three samples (n = 15) to measure the tensile strength of each group. Data were analyzed by a combination of one-way analysis of variance and least significant difference tests. Result: The antibacterial inhibitory effect showed significant differences between groups (A1: 2.9467 ± 0.4163, A2: 3.6500 ± 0.6245, A3: 5.1267 ± 0.2517, A4: 4.7267 ± 0.9238; P = 0.0000; P < 0.05). A diametric tensile strength test confirmed significant differences between groups (A1: 7.2733 ± 5.0046, A2: 6.7667 ± 4.4346, A3: 6.4533 ± 2.9994, A4: 1.0058 ± 1.0058, K1: 15.6167 ± 3.1250; P = 0.009; P < 0.05). Conclusion: Chitosan-based adhesive bonding with good tensile strength has an antibacterial inhibitory effect against Streptococcus mutans.

Comparison of Prevention Methods against Enamel Demineralization adjacent to Orthodontic Bracket Using Fluoride / 대한소아치과학회지

As a common side effect of fixed orthodontic treatment, demineralization of the enamel adjacent to the bracket and band occurs in patients with poor oral hygiene. The purpose of this study was to investigate what is the most effective method to prevent demineralization around the fixed orthodontic appliance among various methods using fluoride. 80 extracted bovine incisors with a healthy surface were classified into four groups as experimental materials: (Group I) Control group, (Group II) V varnish™, (Group III) Tooth Mousse Plus®, (Group IV) Vanish™ XT. After treatment for each group, mineral loss and Vickers surface microhardness were measured at 0, 30, 60 and 90 days after demineralization in artificial carious solution. Mineral loss was the lowest in group IV, followed by group II and group III, which showed a significant difference. The surface microhardness was the lowest in group IV, followed by group II and group III, which showed a significant difference. Through this study, group IV showed the best effect to prevent enamel demineralization around the bracket. Group III showed significant prevention of enamel demineralization compared with the control group, but the effect was less than that of the other groups.

Antimicrobial and anti-caries effect of new glass ionomer cement on enamel under microcosm biofilm model

Abstract The occurrence of caries lesions adjacent to restorations is a serious problem in Dentistry. Therefore, new antimicrobial restorative materials could help to prevent recurrent carious lesions. This study evaluated the effect of a new glass ionomer cement (Ion Z) on the viability of a microcosm biofilm and on the development of enamel demineralization. Enamel samples were filled with the following materials (n=9): A) Ion-Z (FGM Ltda); B) Maxxion R (FGM Ltda); C) Ketac Fil Plus (3M ESPE) and D) no restoration (control). The samples were then exposed to human saliva mixed with McBain saliva (1:50) containing 0.2% sucrose for 14 days. The live and dead bacteria were quantified by fluorescence using a confocal laser-scanning microscope. The enamel demineralization was analyzed using transverse microradiography (TMR). The data were submitted to ANOVA/Tukey or Kruskal-Wallis/Dunn test (p<0.05). Ion Z induced a higher percentage of dead bacteria (60.96±12.0%) compared to the other groups (Maxxion R: 39.8±6.7%, Ketac Fil Plus: 43.7±9.71% and control 46.3±9.5%). All materials significantly reduced the average mineral loss compared to control (Ion-Z 25.0±4.2%vol, Maxxion R 23.4±8.0%vol, Ketac Fil Plus 30.7±7.7 and control 41.2±6.6%vol). Ion-Z was the only material able to significantly improve the mineral content at the surface layer (Zmax: 63.5±18.2%vol) compared to control (38.9±11.3%vol). Ion-Z shows antimicrobial potential, but its anti-caries effect was similar to the other materials, under this model.

Resumo A ocorrência de lesões de cárie adjacentes a restaurações é um sério problema na Odontologia. Portanto, novos materiais restauradores antimicrobianos poderiam ajudar a prevenir as lesões cariosas recorrentes. Este estudo avaliou o efeito de um novo cimento de ionômero de vidro (Ion Z) sobre a viabilidade de um biofilme microcosmo e o desenvolvimento da desmineralização do esmalte. Amostras de esmalte foram restauradas com os seguintes materiais (n=9): A) Ion-Z (FGM Ltda); B) Maxxion R (FGM Ltda); C) Ketac Fil Plus (3M ESPE) e D) sem restauração (controle). As amostras foram submetidas a uma mistura de saliva humana com saliva de McBain (1:50) contendo sacarose a 0,2% por 14 dias. As bactérias vivas e mortas foram quantificadas por fluorescência usando um microscópio confocal de varredura à laser. A desmineralização do esmalte foi analisada usando microradiografia transversal (TMR). Os dados foram submetidos aos testes ANOVA/Tukey ou Kruskal-Wallis/Dunn (p<0,05). O Ion Z induziu uma porcentagem mais elevada de bactérias mortas (60,96 ± 12,0%) comparado aos outros grupos (Maxxion R: 39,8 ± 6,7%, Ketac Fil Plus: 43,7 ± 9,71% e controle 46,3 ± 9,5%). Todos os materiais reduziram significativamente a perda mineral média em relação ao controle (Ion-Z 25,0 ± 4,2% vol, Maxxion R 23,4 ± 8,0% vol, Ketac Fil Plus 30,7 ± 7,7% vol e controle 41,2 ± 6,6% vol). O Ion-Z foi o único material capaz de melhorar significativamente o conteúdo mineral na camada superficial (Zmax: 63,5 ± 18,2% vol) em comparação com o controle (38,9 ± 11,3% vol). Ion-Z mostrou potencial antimicrobiano, mas seu efeito anti-cárie foi semelhante aos outros materiais, sob este modelo.

Influence of different brushing time in oral hygiene in adolescent orthodontic patients and their clinical significances / 吉林大学学报(医学版)

Objective:To study the changes of oral health indexes in adolescent orthodontic patients under different brushing time, and to provide basis for the orthodontists to give effective dental health promotion in clinic.Methods:A total of 123 adolescent orthodontic patients were included, and they were divided into 1-3min, 3-5 min, 5-7 min and 7-10 min groups based on the brushing time recorded in the period of orthodontic treatment.The relationship between different brushing time and oral health indexes was evaluated 1,3,and 6 months after experiment, such as sulcus bleeding index(SBI),plaque index(PLI), debris index-simplified(DI-S) and enamel demineralization index(EDI).Results:Compared with 1-3 min and 3-5 min groups, the SBI, PLI, and DI-S of the patients in 5-7 min group were significantly reduced(P0.05).Conclusion:Brushing teeth more than 5 min can improve the oral hygiene significantly and the best time is 5-7 min;the orthodontists should require the patients to brush teeth at least for 5 min.

Clinical evaluation of the preventing effect of 4 anti-caries preparations on enamel decalcification in orthodontic treatment with fixed appliance / 实用口腔医学杂志

Objective:To evaluate the preventing effects of 4 anti-caries preparations on enamel demineralization in fixed appliance orthodontic treatment.Methods:200 patients treated with fixed appliance were included and randomly divided into 4 groups (n =50),the teeth were treated with fluoride-containing toothpaste,fluoride varnish,fluoride free toothpaste and casein phosphopeptide-amorphous calcium phoaphate(CPP-ACP) respectively.The enamel decalcification incidence was calculated after orthodontic treatment.Results:The incidence of enamel decalcification calculated by tooth number was 16.3％ in fluoride-containing toothpaste group,9.3％ in fluoride varnish group,21.9％ in fluoride free toothpaste and 8.5％ in CPP-ACP group(among groups,P ＜0.05;between CPP-ACP and fluoride varnish,P ＞ 0.05).Conclusion:Fluoride containing preparation can prevent the enamel demineralization during the fixed appliance orthodontic treatment,CPP-ACP and fluoride varnish are more effective.

A clinical study of SIMI mouthguard paint in the treatment of enamel demineralization during orthodontic therapy with fixed applince / 实用口腔医学杂志

Objective:To investigate the efficacy and safety of SIMI mouthguard paint(test group) in the treatment of enamel demineralization during orthodontic therapy with fixed applince.Methods:152 cases underwent orthodontic therapy with fixed applince were included in a randomized,open,positive control trial,and were treated by SIMI and Duraphant fluoride toothpast (control group) respectively(n =76).The enamel opaque spot was observed before and 3 months after using the products.The oral mucosa reactions,asthma attacks or stomach nausea and other adverse events were recorded.Results:150 cases (n =75) completed the trial.The results showed that the test group was non-inferior compared with the control group.No adverse event was found in both groups.Conclusion:SIMI mouthguard paint is effective in control of enamel demineralization during orthodontic therapy with fixed applince.

Efficiency of resin infiltration versus fluride varnish for treatment of post-orthodontic white spot lesions / 中国组织工程研究

BACKGROUND:White spot lesions caused by enamel demineralization are a common side effect of orthodontic treatment. Resin infiltration treatment for white spot lesions has obtained favorable effects, but there is no report on the difference between resin infiltration and fluoride varnish treatment for post-orthodontic white spot lesions. OBJECTIVE:To compare the efficiency of resin infiltration and fluride varnish for treatment of post-orthodontic white spot lesions. METHODS:Twenty-nine patients with post-orthodontic white spot lesions were randomly divided into two groups:one group accepted the resin infiltration treatment and the other group accepted fluoride varnish treatment. Frontal intraoral photos before treatment and 6 months after treatment were col ected for study. The difference in efficiency of resin infiltration and fluride varnish for treatment of post-orthodontic white spot lesion was analyzed and evaluated by both dentists and College students who were not engaged in oral medicine. RESULTS AND CONCLUSION:Except one patient treated with fluride varnish, al the patients completed the referral on schedule. There was significant improvement in the two groups after treatment (P<0.05). Resin infiltration treatment was better than fluoride varnish treatment in post-orthodontic white spot lesions. Thus, resin infiltration that requires fewer referrals and has better effects is an ideal therapy for post-orthodontic white spot lesions.

Fermentation of various sugars and sugar substitutes by oral microorganisms

Objective: To examine acid production of caries-associated strains of oral microorganisms and salivary microorganisms from sugar and sugar substitutes. Methods:Standard and clinical strains of Streptococcus mutans (S. mutans), Lactobacillus casei (L. casei) and Candida albicans were incubated in peptone-yeast-extract media containing 1% test sugar (sucrose, glucose, fructose) or sugar substitutes (xylitol, sorbitol, trehalulose and palatinose) at 37 ℃in 5% CO2 for 24-48 h. The pH of each culture was measured and microbial growth was determined as optical density at 660 nm. Paraffin-stimulated saliva collected from high caries-risk persons were added to media containing 10%test sugar or sugar substitutes. The pH of medium was measured at each time interval from 0-90 minutes. Results:All types of sugar and trehalulose could be fermented by all test microorganisms in pH lower than 5.5 except sucrose by standard strain of L. casei. All sugar and sugar substitutes supported growth of all organisms except xylitol for S. mutans. In the fermentation assay by salivary microorganisms, all sugar could be utilized and produced pH< 5.5 within 10 minutes of incubation and the pH drop was prolonged to until 90 minutes. Conversely, xylitol and palatinose were not fermented by microorganisms in saliva. Conclusions:All test microorganisms could ferment sucrose, glucose, fructose and trehalulose to pH lower than 5.5. Sugar alcohols and palatinose were not utilized well by organisms and may be used as sugar substitutes to reduce dental caries incidence. However, further studies particularly clinical investigations are required to evaluate the cariogenicity of these sugar substitutes.

The effects of a sealant resin on enamel demineralization in orthodontic bracket bonding / 대한치과교정학회지

The purpose of this study was to evaluate the effects of a sealant resin on enamel demineralization in orthodontic bracket bonding. The forty eight extracted sound bovine teeth were subdivided into four groups and treated with Phase II(R) (Reliance, Itasca, Ill) on the surface. Group 1 was not treated. Group 2 was acid etched with 37% phosphoric acid for 30 seconds. Group 3 was applied with sealant after acid etching. Group 4 was applied with resin paste after acid etching and sealant application. Each group was demineralized in artificial caries solution. Demineralized enamel depth was measured by confocal laser scanning microscopy. The results were as follows: the mean demineralized enamel depth was 47.4 micrometer (Group 1), 61.8 micrometer (Group 2), 13.9 micrometer (Group 3), 8.2 micrometer (Group 4); the demineralized enamel depth was increased in Group 2 than in Group 1 (p < 0.05); the demineralized enamel depth was reduced in Group 3 than in Group1 and Group 2 with statistically significant differences (p < 0.05); and demineralization in Group 4 was very little. The results of the present study indicate that sealant application is useful for reducing enamel demineralization in orthodontic bracket bonding.

Relationship between enamel demineralization and ultrastructure of surface layer under driving forces of dental plaque fluid / 第三军医大学学报

Objective To evaluate the effect of driving forces similar to those found in dental plaque fluid on the enamel demineralization and ultrastructure of surface layer.Methods The sections of human enamel were exposed to lactic acid solutions with degree of saturation with respect to enamel and degree of saturation with respect to fluoroapatite for 96 h at 25 ℃,using the deionized water as control in the same conditions.Enamel demineralization was monitored using SEM and confocal laser scanning microscopy(CLSM).Results Only was enamel subsurface demineralization detected in solutions with DS_(EN)(0.1-0.3).Enamel mineral loss and micropores of surface layer decreased significantly with increasing DS_(EN) and DS_(FA) values.However,no mineral loss and micropores of surface layer was observed in sections of enamel exposed to solutions with DS_(EN) values of 0.4 and 0.5,which were covered with homogeneous remineralization layer.Conclusion The demineralization driving forces similar to dental plaque fluid under different DS_(EN) and DS_(FA) have significant effects on the surface layer of enamel and the subsurface demineralization process.

The effects of fluoride releasing orthodontic sealants on the prevention and the progressive inhibition of enamel demineralization in vitro / 대한치과교정학회지

The purpose of this study was to identifu the preventive and the preventive and the progressive inhibitory effects of enamel demineralization with fluoride releasing light-and self-cured orthodontic sealants(FluoroBond), in vitro, under the polarizing light microscope and the scanning electon microscope. The polarizing light microscopic group was subdivided into seven groups(Group A-Group G). The scanning electron microscopic group was also subdivided into seven groups(Group A'-Group G'). For polarzing light microscopic evaluation, longitudinal sections were made longitudinally by Maruto cutter(Maruto Co., Japan) and Maruto grinding machine(Maruto Co., Japan). Sections were examined and photographed by the polarizing light microscope(Olympus Optical Co., Japan) using crossed polars and with the enamel rod longitudinal axis oriented at 45degrees to the extinction position. For scanning electron microscopic evaluation, the specimens were coated with a highly conducting layer of gold palladium in a model Hus-4 high0vacuum evaporator* and examined in an ISI-100B scanning electron microcpe** operated at 20kV. The results of this study were as follows : 1. The mean deoths of artificial carious lesions under a polarized light microscope were Group A(5.08microgram), Group B(47.82microgram), Group C(8.42microgram), Group D(7.20microgram), Group E(85.41microgram), Group F(60.38microgram), Group G(60.13microgram). 2. There were statistically significant differences in Group B compared with Group A, C, and D(p<0.05), and also, in Group E compared with Group F and Group G(p<0.05). 3. Light-and self-cured orthodontic sealants had the preventive effects of enamel demineralization. 4. Light-and self-cured orthodontic sealants had the progressive inhibitory effects enamel demineralization. 5. The time progress of demineralizing agent no ingluecse on the samples of light-and self-cured orthodontic sealants under the scanning electron microscope. 6. There was no difference between the specimens of light-and self-cured orthodontic edalants both in the polarized light microscopic group and in the scanning electron microscopic group. *Hitachi Ltd, Tokyo, Japan **International Scientific Instruments, Santa Clara, Calif.