Objectives
To achieve in vitro remineralization of enamel white spot lesions (WSLs) via a mesoporous delivery system of amorphous calcium phosphate (ACP) precursors.
Materials and methods
...Amine-functionalized expanded pore mesoporous silica (aMSN) was loaded with polyacrylic acid–stabilized amorphous calcium phosphate (PAA-ACP) to develop a carrier-based delivery system (PAA-ACP@aMSN). Thirty-six artificial WSLs samples were created and randomly assigned to three treatments: artificial saliva solution (negative control,
n
= 12), casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) slurry (
n
= 12), and PAA-ACP@aMSN slurry (
n
= 12). Surface microhardness, Raman intensity, and color were measured before/after artificial demineralization and after remineralization treatments to evaluate the remineralization level of each sample. SEM images were taken on the surface and cross-section of samples to observe microstructure changes.
Results
The surface microhardness recovery ratio (%SMHRR), Raman intensity change ratio (%ICR), and color recovery ratio (%CRR) were not significantly different between CPP-ACP and PAA-ACP@aMSN groups (
P
> 0.05), but both of them had significantly higher %SMHRR, %ICR, and %CRR values than negative control (
P
< 0.01). SEM images showed that apparent enamel prism imprints and inter-prism gaps in negative control were masked by mineral deposition in the PAA-ACP@aMSN and CPP-ACP groups.
Conclusions
PAA-ACP@aMSN has an ability to remineralize enamel WSLs.
Clinical relevance
The carrier-based amorphous calcium phosphate delivery system has great potential to serve as a remineralizing agent for the treatment of WSLs.
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 antibacter
Objectives
To compare the effectiveness of remineralizing agents in the prevention and reversal of white spot lesions (WSLs), which occur during fixed orthodontic treatment, through a systematic ...review and network meta-analysis.
Materials and methods
We reviewed controlled randomized clinical trial (RCT) data querying nine databases combined with a manual search (last search date: March 10, 2020). Of 2273 identified studies, 36 RCTs were finally included. After study selection and data extraction, pair-wise and network meta-analyses were performed to analyze the effectiveness of remineralizing agents in the prevention and reversal of WSLs in the short term (≤ 3 months) and long term (> 3 months). The risk of bias was assessed based on the Cochrane guidelines. Statistical heterogeneity, inconsistencies, and cumulative ranking were also evaluated.
Results
In terms of WSL prevention, sodium fluoride (NaF) varnish had the highest cumulative ranking for the short-term decalcification index (99.3%); acidulated phosphate fluoride (APF) foam ranked first for long-term incidence (96.9%), followed by difluorosilane (Dfs) varnish and high-concentration fluoride toothpaste (HFT) (79.4% and 77.4%, respectively). In the reversal of WSLs, no significant difference was found among different agents or their combinations for the two available outcomes (short-term integrated fluorescence loss and short-term percentage of fluorescence loss).
Conclusions
In the prevention of WSLs, APF foam showed the best remineralizing effectiveness in the long term (after debonding), followed by Dfs varnish and HFT. It is unclear whether remineralizing agents can effectively reverse WSLs based on the existing evidence.
Clinical Relevance
APF foam may be recommended as a remineralizing agent for preventing orthodontically induced WSLs.
PROSPERO registration number
CRD42019116852.
In the process of orthodontic treatment, the presence of orthodontic appliances makes it difficult to clean tooth surfaces. This can lead to an increased level of bacterial colonization, resulting in ...enamel demineralization and periodontal diseases. Considering the large surface area that orthodontic appliances usually have and that they can be in direct contact with bacteria throughout the treatment, modifications in the form of coatings on the surface of orthodontic appliances can be an effective and practical approach to reducing bacterial proliferation and preventing relevant adverse effects. In this mini-review, we discuss various antibacterial coatings which have been applied onto orthodontic appliances in recent 5 years, as well as their antibacterial mechanisms and methods for the preparation of these coatings. From this mini-review, both orthodontists and researchers can get the latest findings in the field of antibacterial coatings onto orthodontic appliances, which is helpful for the decision-making in clinical practice and research activities.
Perceiving incoming environmental information is critical for optimizing plant growth and development. Multiple B-box proteins (BBXs) play essential roles in light-dependent developmental processes ...in plants. However, whether BBXs function as a signal integrator between light and temperature in tomato plants remains elusive. In this study, 31
SlBBX
genes were identified from the newly released tomato (
Solanum lycopersicum
) genome sequences and were clustered into five subgroups. Gene structure and protein motif analyses showed relatively high conservation of closely clustered
SlBBX
genes within each subgroup; however, genome mapping analysis indicated the uneven distribution of the
SlBBX
genes on tomato chromosomes. Promoter
cis
-regulatory elements prediction and gene expression indicated that
SlBBX
genes were highly responsive to light, hormones, and stress conditions. Reverse genetic approaches revealed that disruption of
SlBBX7, SlBBX9
, and
SlBBX20
largely suppressed the cold tolerance of tomato plants. Furthermore, the impairment of
SlBBX7, SlBBX9
, and
SlBBX20
suppressed the photosynthetic response immediately after cold stress. Due to the impairment of non-photochemical quenching (NPQ), the excess photon energy and electron flow excited by low temperature were not consumed in
SlBBX7-, SlBBX9-
, and
SlBBX20-
silenced plants, leading to the over reduction of electron carriers and damage of the photosystem. Our study emphasized the positive roles of light signaling transcription factors SlBBXs in cold tolerance in tomato plants, which may improve the current understanding of how plants integrate light and temperature signals to adapt to adverse environments.
Plants experience low ambient temperature and low red to far-red ratios (L-R/FR) of light due to vegetative shading and longer twilight durations in cool seasons. Low temperature induce ...photoinhibition through inactivation of the photosynthetic apparatus, however, the role of light quality on photoprotection during cold stress remains poorly understood. Here, we report that L-R/FR significantly prevents the overreduction of the entire intersystem electron transfer chain and the limitation of photosystem I (PSI) acceptor side, eventually alleviating the cold-induced photoinhibition. During cold stress, L-R/FR activated cyclic electron flow (CEF), enhanced protonation of PSII subunit S (PsbS) and de-epoxidation state of the xanthophyll cycle, and promoted energy-dependent quenching (qE) component of non-photochemical quenching (NPQ), enzyme activity of Foyer-Halliwell-Asada cycle and D1 proteins accumulation. However, L-R/FR –induced photoprotection pathways were compromised in tomato
PROTON GRADIENT REGULATION5
(
PGR5
) and
PGR5-LIKE PHOTOSYNTHETIC PHENOTYPE1A
(
PGRL1A
) co-silenced plants and
NADH DEHYDROGENASE-LIKE COMPLEX M
(
NDHM
) -silenced plants during cold stress. Our results demonstrate that both PGR5/PGRL1- and NDH-dependent CEF mediate L-R/FR –induced cold tolerance by enhancing the thermal dissipation and the repair of photodamaged PSII, thereby mitigating the overreduction of electron carriers and the accumulation of reactive oxygen species. The study indicates that there is an anterograde link between photoreception and photoprotection in tomato plants during cold stress.
Objectives:
To assess the current COVID-19 related experiences, knowledge, attitudes, and behaviors among orthodontists, orthodontic residents, and orthodontic nurses in China, and to identify ...factors associated with their self-perceived and actual level of knowledge, as well as their willingness to treat/care for COVID-19 patients.
Materials and Methods:
A cross-sectional online survey was conducted in China using a 37-item questionnaire developed based on previous research. A professional online survey tool (
www.wjx.cn
) and a social media platform (WeChat) were used to display and distribute the questionnaire. Data were collected during April 11 to 13, 2020, when most regions of China had resumed dental practice except for high-risk regions such as Wuhan. Then the data were analyzed with multivariable generalized estimating equations.
Results:
A total of 2,669 valid questionnaires were collected. Orthodontic services were suspended for nearly all respondents (97.8%) during the epidemic, and 68.0% had resumed work by the time they completed the questionnaire. The majority of respondents (80.2%) were confident that they understood COVID-19 related knowledge, but most of them only correctly answered less than half of the questions testing their actual level of knowledge. About two-thirds (64.1%) were willing to treat/care for patients with confirmed or suspected COVID-19. The completion of relevant training programs was significantly associated with more confidence in knowledge mastery (
P
< 0.001) and a higher actual level of knowledge (
P
< 0.001), but did not increase their willingness to treat/care for patients with COVID-19 (
P
= 0.235).
Conclusions:
Before work resumption, COVID-19-related training programs are essential for the improvement of knowledge, confidence, and preparedness of orthodontic professionals. Sufficient and proper protection should also be provided to ensure safety and reduce the psychological burden on them.
Clinical Relevance:
The findings can provide evidence for policy-making related to the resumption of elective dental services.
Enamel demineralization, as a type of frequently-occurring dental problem that affects both the health and aesthetics of patients, is a concern for both dental professionals and patients. The main ...chemical composition of the enamel, hydroxyapatite, is easy to be dissolved under acid attack, resulting in the occurrence of enamel demineralization. Among agents for the preventing or treatment of enamel demineralization, amorphous calcium phosphate (ACP) has gradually become a focus of research. Based on the nonclassical crystallization theory, ACP can induce the formation of enamel-like hydroxyapatite and thereby achieve enamel remineralization. However, ACP has poor stability and tends to turn into hydroxyapatite in an aqueous solution resulting in the loss of remineralization ability. Therefore, ACP needs to be stabilized in an amorphous state before application. Herein, ACP stabilizers, including amelogenin and its analogs, casein phosphopeptides, polymers like chitosan derivatives, carboxymethylated PAMAM and polyelectrolytes, together with their mechanisms for stabilizing ACP are briefly reviewed. Scientific evidence supporting the remineralization ability of these ACP agents are introduced. Limitations of existing research and further prospects of ACP agents for clinical translation are also discussed.
With the deepening of research in oral microbiomics, an important relationship between changes in the oral microbiome and orthodontic treatment has been found. Orthodontic treatment will have an ...impact on the oral and systemic microbiome. The presence of oral appliances can change the quantity and quality of the oral microbiometo and increase the risk of oral and even systemic diseases in patients undergoing orthodontic treatment. Compared with fixed orthodontic treatment, clear aligners will not have a harmful impact on the structure of the oral microbiome, which is more conducive to maintain oral health during the orthodontic treatment process. In addition, different bracket types and materials can lead to different changes in the oral microbiome, and the occurrence and development of orthodontic-related diseases, such as white spot lesions, dental caries, gingivitis and periodontitis, are also related to changes in the oral microbiome. At present, the role of the oral microbiome in the process of orthodont
To systematically review
studies that evaluated the effects of plant extracts on dentin bonding strength.
Six electronic databases (PubMed, Embase, VIP, CNKI, Wanfang and The Cochrane Library) were ...searched from inception to September 2021 in accordance with the Preferred Reporting Items for Systematic Reviews (PRISMA).
studies that compared the performance of dental adhesives with and without the plant extracts participation were included. The reference lists of the included studies were manually searched. Two researchers carried out study screening, data extraction and risk of bias assessment, independently and in duplicate. Meta-analysis was conducted using Review Manager 5.3.
A total of 62 studies were selected for full-text analysis. 25 articles used the plant extracts as primers, while five added the plant extracts into adhesives. The meta-analysis included 14 articles of
studies investigating the effects of different plant extract primers on dentin bonding strength of etch-and-rinse and self-etch adhesives, respectively. The global analysis showed statistically significant difference between dental adhesives with and without plant extract primers. It showed that the immediate bond strength of dental adhesives was improved with the application of plant extract primers.
The application of proanthocyanidin (PA) primers have positive effect on the
immediate bonding strength of dental adhesives irrespective of etch-and-rinse or self-etch modes.
PDF
