Subgingival Microbial Changes During the First 3 Months of Fixed Appliance Treatment in Female Adult Patients

The Impact of Orthodontic Adhesives on the Subgingival Microbiota During Early Fixed Appliance Therapy: A Pilot Study

Background and Objectives: The most common method for treating malocclusions today is fixed orthodontic therapy, during which brackets and tubes are bonded to the surface of the teeth, which makes oral hygiene difficult to maintain. Increased plaque retention, gingival bleeding, and gingivitis can be diagnosed in the early phases of treatment. The periodontal response to plaque accumulation can be explained by quantitative and qualitative changes in the subgingival microbiota. The aim of our research was to investigate the changes in the subgingival microbiota that occurred within 6-8 weeks after bonding when two different orthodontic adhesives were used. Materials and Methods: Thirty patients were followed; molar tubes were bonded with a composite (C) in fifteen cases, and in the other fifteen cases, they were bonded with glass ionomer cementum (GIC). A microbiological sample was taken from the gingival sulcus of the maxillary first molars at the time of appliance placement (T1) and 6-8 weeks (T2) after bonding. Bacterial DNA detection was performed using the micro-IDent®plus11 (Hain Lifescience GmbH, Germany) PCR (polymerase chain reaction) method. The statistical analysis included McNemar's test to analyze the paired binary data and Fisher's Exact Test to compare the prevalence of each of the 11 bacteria at T1 and, ultimately, T2 between the two studied groups. The Bonferroni correction was also applied. Results: When analyzing GIC vs. C at T1 and T2, none of the studied pathogens showed significant differences. Conclusions: Given the lack of statistical significance, these trends do not confirm a definitive impact of the procedure on bacterial presence. The increased presence of periodontal pathogens might suggest that bonding does not reduce the bacterial loading of subgingival microbiota. Less protective effects of the GIC intervention against Tannerella forsythia and Eubacterium nodatum bacteria were detected.

Influence of orthodontic appliances and nitrate on the oral microbiota

In this pilot study, we investigated the bacterial changes introduced on the subgingival, tongue, and saliva microbiota during fixed orthodontic treatment, with or without daily administration of nitrate-containing beet juice for 2 weeks in 22 individuals with good general health. We followed clinical parameters in combination with microbiota changes before, after 2 weeks, and after 6 months of treatment with fixed orthodontic appliances. In accordance with variations in community composition at the sampling sites, effects to orthodontic treatment differed. Subgingival communities responded promptly to orthodontic treatment with no additional structural changes over time, whereas saliva and tongue communities were affected only after extended treatment. Periodontal pathogens such as Selenomonas sputigena were enriched in subgingival communities, whereas Streptococcus mutans was enriched in saliva. Specifically, Rothia mucilaginosa increased tremendously in relative abundance in both tongue and saliva communities. The effect of beet juice on microbial composition was significant in subgingival samples even though the differences were not mirrored in single differentially distributed genera or species. This indicates changes in the complete subgingival microbial net of interacting species. However, the prevention of Corynebacterium matruchotii enrichment by beet juice may be important for prevention of biofilm formation. Enrichment of Neisseria flavescens group bacteria and Abiotrophia and depletion of different Actinomyces and Stomatobaculum were observed on tongue communities. We conclude that subgingival microbiota are rapidly affected by fixed orthodontic appliances and can be positively influenced by regular administration of nitrate-containing juice. KEY POINTS: • The subgingival site, tongue, and saliva contain different microbiota • The microbiota react differently to orthodontic treatment and beet juice • Key genera and species affected by treatments were identified.

Exploring the impact of orthodontic appliances on the oral microbiome and inflammatory parameters

BACKGROUND

The symbiotic relationship between the oral microbiome and the host immune system is a prerequisite of oral health. Disruptions to this system can be associated with the development of diseases like dental caries. Introducing orthodontic treatments, such as aligners and fixed appliances, might impact this microbial ecosystem. This study evaluated potential changes in salivary microbiome and the level of inflammatory marker myeloid-related protein 8/14 in patients undergoing orthodontic treatment with aligners or fixed appliances.

METHODS

Forty-eight patients were divided into two groups for treatment with fixed appliances or clear aligners. Unstimulated saliva samples were collected at baseline, three, and six months for microbiome analysis via 16 S rRNA sequencing and MRP-8/14 level measurement using ELISA.

RESULTS

Among 503 identified microbial species, no significant changes were noted in overall microbiome. A considerable increase of caries-relevant species could not be observed either. MRP-8/14 levels remained unchanged across treatments, indicating no alterations in the inflammatory level.

CONCLUSION

Orthodontic treatment with fixed or removable appliances does not significantly alter the salivary microbiome or influence inflammation, suggesting that these interventions are unlikely to affect oral health negatively.

Dynamics of the oral microbiome during orthodontic treatment and antimicrobial advances for orthodontic appliances

The oral microbiome plays an important role in human health, and an imbalance of the oral microbiome could lead to oral and systemic diseases. Orthodontic treatment is an effective method to correct malocclusion. However, it is associated with many adverse effects, including white spot lesions, caries, gingivitis, periodontitis, halitosis, and even some systematic diseases. Undoubtedly, increased difficulty in oral hygiene maintenance and oral microbial disturbances are the main factors in developing these adverse effects. The present article briefly illustrates the characteristics of different ecological niches (including saliva, soft tissue surfaces of the oral mucosa, and hard tissue surfaces of the teeth) inhabited by oral microorganisms. According to the investigations conducted since 2014, we comprehensively elucidate the alterations of the oral microbiome in saliva, dental plaque, and other ecological niches after the introduction of orthodontic appliances. Finally, we provide a detailed review of recent advances in the antimicrobial properties of different orthodontic appliances. This article will provide researchers with a profound understanding of the underlying mechanisms of the effects of orthodontic appliances on human health and provide direction for further research on the antimicrobial properties of orthodontic appliances.

Effects of clear aligners and traditional removable appliances on oral microbiome in mixed dentition: a comparative study

BACKGROUND

This prospective study aims to investigate the comparative effects of clear aligners (CA) and traditional removable appliances (RA) on the cariogenic risk of patients in mixed dentition, focusing on the oral microbiome.

METHODS

25 children were included and assigned into CA and RA groups. Supragingival plaque and saliva samples were collected, and clinical parameters including Decay-missing-filled teeth index (DMFT), Plaque Index (PI) and Gorelick Index (GI) were recorded before treatment (T0) and after 6-month follow-up (T1). DNA was extracted from supragingival plaque and saliva and analyzed via 16S rDNA gene sequencing.

RESULTS

Clinical parameters showed no statistically significant difference between groups at each time point or within group over time (p > 0.05). In both RA and CA groups, saliva exhibited significantly higher alpha diversity compared to supragingival plaque at T1, as indicated by the significantly higher Chao1 and Shannon indexes (p < 0.05). Regarding beta diversity, significant difference was observed in saliva and supragingival plaque samples between T0 and T1 within group RA (p < 0.05, Adonis), whereas no such significance was noted in the CA group (p > 0.05, Adonis). At the genus level, Lactobacillus exhibited a statistically significant increase in saliva and supragingival plaque of group RA from T0 to T1 (p < 0.05), and an increasing trend in the group CA without statistical significance (p > 0.05). At T1, Lactobacillus levels were comparable between groups, whereas species-level analysis revealed distinct cariogenic species.

CONCLUSION

Both clear aligners and traditional removable appliances resulted in elevated cariogenic risk of patients in mixed dentition at the microbial level. Distinct alterations in cariogenic species were observed to be induced by various orthodontic appliances.

Supragingival microbiome variations and the influence of Candida albicans in adolescent orthodontic patients with gingivitis

Introduction

Gingivitis is a prevalent complication in adolescents undergoing fixed orthodontic treatments. However, changes in the supragingival microbiome associated with gingivitis and the impact of Candida albicans remain elusive. Therefore, we investigated supragingival microbiome discrepancy and C. albicans colonization in adolescent orthodontic patients with gingivitis.

Methods

Dental plaques were collected from 30 gingivitis patients and 24 healthy adolescents, all undergoing fixed orthodontic treatment. The supragingival microbiome composition was analyzed using 16S rRNA sequencing. C. albicans colonization was determined using fungal culture and real-time quantitative polymerase chain reaction.

Results

Our analysis revealed significantly heightened microbial diversity in the Gingivitis group. Notably, patients with gingivitis exhibited an enrichment of periodontal pathogens, such as Saccharibacteria (TM7) [G-1], Selenomonas, Actinomyces dentalis, and Selenomonas sputigena. Additionally, 33% of the gingivitis patients tested positive for C. albicans, exhibiting significantly elevated levels of absolute abundance, while all healthy patients tested negative. Significant differences in microbial composition were also noted between C. albicans-positive and -negative samples in the Gingivitis group.

Conclusion

Significant disparities were observed in the supragingival microbiome of adolescent orthodontic patients with and without gingivitis. The presence of C. albicans in the supragingival plaque may alter the microbiome composition and potentially contribute to gingivitis pathogenesis.

Microbiological Advances in Orthodontics: An Overview and Detailed Analysis of Temporary Anchorage Devices

Dental biofilm is the initiating factor of oral diseases, such as periodontitis and caries. Orthodontic treatment could alter the microbiome structure balance, and increase the risk of such diseases. Furthermore, fixed appliances can induce temporary changes in the microbiome community, and the changes that clear aligners bring are smaller by comparison. Temporary anchorage devices (TADs) are skeletal anchorages that are widely used in orthodontic treatment. Microorganisms affect the occurrence and development of inflammation surrounding TADs. At present, existing researches have verified the existence of plaque biofilm on the surface of TADs, but the formation of plaque biofilm and plaque composition under different stable conditions have not been fully understood. The development of high-throughput sequencing, molecular biology experiments, and metabonomics have provided new research ideas to solve this problem. They can become an effective means to explore the microbiome surrounding TADs.

Taxonomic Analysis of Oral Microbiome during Orthodontic Treatment

Background

Orthodontic appliances induce significant changes in the oral microbiome, but this shift in microbial composition has not been well established by the available evidence yet.

Objectives

To perform a systematic review of existing literature in order to assess the taxonomic microbial changes in orthodontic patients during Fixed Appliance Treatment (FAT) and Clear Aligner Treatment (CAT), using next-generation sequencing (NGS) technique of the bacterial 16S rRNA gene. Search Methods and Selection Criteria. The search for articles was carried out in PubMed, including articles published in English until May 2021. They included every human study report potentially relevant to the review. Data Collection and Analysis. After duplicate study selection and data extraction procedures according to the PICOS scheme, the methodological quality of the included papers was assessed by the Swedish Council on Technology Assessment in Health Care Criteria for Grading Assessed Studies (SBU) method.

Results

The initial search identified 393 articles, 74 of which were selected by title and abstract. After full-text reading, six articles were selected according to inclusion criteria. The evidence quality for all the studies was moderate.

Conclusions

Orthodontic treatment seems to transiently affect the composition of subgingival microbiome, although not salivary, maintaining a stable microbial diversity. Different results were found in the shift of microbiome between plaque and saliva, depending on the type of orthodontic treatment. This review should be interpreted with some caution because of the number, quality, and heterogeneity of the included studies.

The Effects of Static Magnetic Field on Orthodontic Tooth Movement in Mice

The application of static magnetic field (SMF) has been considered an effective and noninvasive method to accelerate orthodontic tooth movement. The objective of this study was to explore the effects of SMF on orthodontic tooth movement in mice. A total of 105 Balb/c mice (body mass: 25-30 g) were divided into experimental group (SMF + force, 48), control group (force only, 48), and blank group (neither SMF nor force, 9). After the placement of orthodontic appliances, the experimental group was exposed to the SMF environment generated by Neodymium-iron-boron (NdFeB) magnets with an intensity of 20-204 mT. At 1, 3, 7, 14, 21, and 28 days after appliance insertion, eight animals in both experimental and control groups were sacrificed and the left maxillae were dissected to measure the distance of tooth movement, respectively. Meanwhile, the width of periodontal ligament (PDL), length of hyalinized zone, and the number of osteoclasts were evaluated by hematoxylin-eosin and tartrate-resistant acid phosphatase staining. We finally found that the experimental group demonstrated an enhanced rate and greater cumulative amount of tooth movement than the control group (0.2887 ± 0.0041 mm vs. 0.2114 ± 0.0089 mm, P < 0.05). On Days 7, 14, and 28, the experimental group also displayed a significantly greater width of PDL. Earlier formation and removal of the hyalinized zone, and significantly more osteoclasts were observed in the experimental group as well. The results suggested that SMF may be a promising nonsurgical intervention to accelerate orthodontic tooth movement. © 2021 Bioelectromagnetics Society.

Salivary microbiome and periodontal status of patients with periodontitis during the initial stage of orthodontic treatment

INTRODUCTION

Patients with severe periodontitis typically present with pathologic tooth migration. To improve esthetics and masticatory function, orthodontic treatment is required. Research on periodontal orthodontic treatment has been sparse, particularly from the microbial perspective. Hence, we analyzed the microbial and clinical changes in patients with well-controlled periodontitis in the early stage of orthodontic treatment.

METHODS

Ten patients with well-controlled periodontitis were asked to collect saliva before and 1 and 3 months after appliance placement (T0, T1, and T2, respectively) and underwent clinical examinations before and 1, 3, and 6 months after appliance placement (T0, T1, T2, and T3, respectively). The microbial community of saliva was analyzed by 16S rRNA gene sequencing. Gingival index, the plaque index, and the probing pocket depth were clinically assessed.

RESULTS

The plaque index significantly increased from T0 to T1 and decreased at T2 and T3. The probing pocket depth and gingival index increased slightly at T2, but not significantly, in both the high-risk site and low-risk site. The alpha and beta diversity increased at T1. The microbial community structure was similar at T0 and T2. The relative abundance of core genera and periodontal pathogens was stable during the initial 3 months of orthodontic treatment.

CONCLUSIONS

The orthodontic appliance promoted plaque accumulation and altered the microbial community of patients with well-controlled periodontitis during the first month of orthodontic treatment. The microbial community returned to the basal composition at 3 months after appliance placement, and the periodontal inflammation during the 6-months orthodontic treatment was under control.

Changes in the Microbiome of the Inner Surface of Clear Aligners After Different Usage Periods

Clear aligners are removable orthodontic appliances that cover the tooth surface. The microbial composition and pH of the inner surface of aligners directly affect the enamel health. In this study, eight subjects who used the same type of clear aligners were instructed to brush their teeth normally and to not clean their aligners until sampling. Saliva and the contents of the inner surface of the aligners (liquid and plaque) were collected at 0 h (T0), 4 h (T4), 8 h (T8), 12 h (T12), and 24 h (T24) after usage, and pH values and microbial compositions were measured. The microbial composition was analyzed with 16S rRNA gene sequencing, and changes were assessed based on operational taxonomic unit abundance. The pH, alpha diversity values, and abundance of specific microbes on the inner surface of the aligners gradually decreased from T0 to T24 (P < 0.05). An insignificant increase in microbial community beta diversity was observed from T0 to T24. Principal component analysis revealed that the microbial composition at T0 was different from at T12 and T24. The relative abundances of phylum Firmicutes (P < 0.01), orders Lactobacillales and Bacteroidales (P < 0.05), and genus Streptococcus and species Streptococcus infantis increased significantly, while those of genera Actinomyces and Rothia and species Rothia aeria decreased significantly at T24 (P < 0.05). These findings reveal that uncleaned aligners might lead to enamel damage, especially after continuous usage for 12 h. Thus, clear aligners should be cleaned after 12 h of usage or at least within 24 h of usage.

Salivary microbial changes during the first 6 months of orthodontic treatment

Background

Orthodontic treatment is widely used to treat malocclusion. However, the influence of treatment on the oral microbiome remains unclear. In this study, we investigated salivary microbial changes in patients undergoing orthodontic treatment.

Methods

In total, 19 orthodontic patients participated in this study. Saliva samples were collected at the following three timepoints: before (T0) and 3 months (T1) and 6 months (T2) after the placement of orthodontic appliances. High-throughput sequencing was performed based on the 16S rRNA gene V4 region.

Results

The phyla of Proteobacteria, Bacteroidetes, Firmicutes, Actinobacteria and Fusobacteria were predominant. Observed Species, Chao1 and ACE, which represent α diversity, were significantly decreased at T1 and subsequently increased at T2. In addition, the β diversity at T1 based on the Bray-Curtis distances differed from T0 and T2. The relative abundances of Prevotella, Porphyromonas and Peptostreptococcus were decreased with treatment, whereas those of Capnocytophaga and Neisseria exhibited the opposite results. In total, 385 of 410 operational taxonomic units were shared at T0, T1 and T2. The co-occurrence networks with hub nodes at T1 were the most complex.

Conclusion

Orthodontic treatment temporarily affected the saliva microbial community. This dynamic alteration in species did not induce deterioration in oral health. Oral hygiene instructions were necessary and should be emphasized during each visit. Further studies with longer observation periods and more participants are required.