Current Enamel Remineralization Therapies Have Limited Effects on Postorthodontic White Spot Lesions

White spot lesion-related perception of aesthetics and treatment satisfaction among orthodontic patients, orthodontists and other dental specialists

OBJECTIVE

To investigate the impact of various degrees of white spot lesions (WSLs) of maxillary anterior teeth on the aesthetic perception and treatment satisfaction among orthodontic patients, orthodontists and other dental specialists and to evaluate the differences among the three groups.

METHODS

A total of 45 orthodontic patients (OP), 45 orthodontists (OR) and 45 other dental specialists (OS) were recruited. Subjective evaluations of perceived aesthetics and treatment satisfaction were performed towards eight digitally generated photographs of maxillary anterior teeth with incremental degrees of WSLs using a numerical visual analogue scale (VAS) from 0 to 100. Data were collected and analysed with descriptive statistics, repeated one-way analysis of variance and multivariable generalized estimating equations.

RESULTS

A total of 135 valid questionnaires were collected. Regarding aesthetic scores for WSLs, OP gave more positive scores than OR and OS (p < .05) towards excessive white spot formation without colouration and were more tolerant than OR (p < .05) towards excessive white spot formation with slight colouration. The level of treatment satisfaction for slight to severe WSLs without cavitation was higher in OP than OR. Patients with higher education levels had more negative scores for aesthetic perception and treatment satisfaction (p < .05). Patients who brushed teeth more frequently scored lower in treatment satisfaction (p < .05).

CONCLUSIONS

Orthodontists were the most critical when evaluating aesthetics and treatment satisfaction for slight to severe WSLs without cavitation. For orthodontic patients, better oral hygiene habits and higher education levels were associated with more critical attitudes towards WSLs.

Antibacterial and fluorescent clear aligner attachment resin modified with chlorhexidine loaded mesoporous silica nanoparticles and zinc oxide quantum dots

OBJECTIVES

To develop an antibacterial and fluorescent clear aligner attachment resin via the incorporation of chlorhexidine loaded pore-expanded mesoporous silica nanoparticles (CHX@pMSN) and amino-silane functionalized zinc oxide quantum dots (aZnO_QDs), and to evaluate its antibacterial activity, fluorescence capability, esthetic properties, mechanical performance and biocompatibility.

METHODS

CHX@pMSN and aZnO_QDs were incorporated into the commercial resin composites (Filtek Z350 XT, 3M) at different mass fractions, control group: Filtek; fluorescent attachment resin (FAR): Filtek + 3 wt% aZnO_QDs; antibacterial and fluorescent attachment resin (AFAR)-1: Filtek + 3 wt% aZnO_QDs + 1 wt% CHX@pMSN; AFAR-2: Filtek + 3 wt% aZnO_QDs + 3 wt% CHX@pMSN; AFAR-3: Filtek + 3 wt% aZnO_QDs + 5 wt% CHX@pMSN. CHX release, antibacterial activity, fluorescence capability, color change, stain resistance, degree of conversion, depth of cure, polymerization shrinkage, water sorption and solubility, softening in solvent, flexural strength, flexural modulus, shear bond strength, and cytotoxicity were evaluated comprehensively.

RESULTS

CHX could be continuously released from the AFAR groups for up to 30 days. CFU, MTT, lactic acid production, SEM and CLSM evaluation showed AFAR-2 and AFAR-3 could effectively inhibit S. mutans biofilms even after 1-month aging. Only AFAR-3 showed clinically perceptible color change and all the experimental groups were not more susceptible to staining. AFAR-1 and AFAR-2 could suppress polymerization shrinkage and enhance the resistance to degradation without compromising other properties, including degree of conversion, water sorption and solubility, flexural strength, flexural modulus, and shear bond strength. Depth of cure of all the four experimental groups was significantly decreased (p < 0.05) but still within the ISO standard. CCK-8 assay and live/dead cell staining denied the cytotoxicity of experimental resins. Fluorescence intensity tests showed that FAR and AFAR-2 could emit strong yellowish fluorescence under the excitation of ultraviolet for up to six months.

CONCLUSIONS

AFRA-2 possessed long-term antibiofilm activity, strong fluorescence capability and satisfying biocompatibility without compromising esthetic and mechanical properties. This study proposed a new strategy for reducing bacteria accumulation around the attachment, which is also promising in helping orthodontists to remove the attachment thoroughly and precisely.

Recent advances in antibacterial coatings for orthodontic appliances

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.

Bond Strength Survival of a Novel Calcium Phosphate-Enriched Orthodontic Self-Etching System after Various Ageing Protocols: An In Vitro Study

Objective

This study aimed to evaluate the orthodontic bond strength and enamel-preserving ability of a hydroxyapatite nanoparticles-containingself-etch system following exposure to various ageing methods.

Materials and Methods

Hydroxyapatite nanoparticles (nHAp) were incorporated into an orthodontic self-etch primer (SEP, Transbond™ plus) in three different concentrations (5%, 7%, and 9% wt) and tested versus the plain SEP (control) for shear bond strength (SBS), adhesive remnant index (ARI) scores, and enamel damage in range-finding experiments using premolar teeth. The best-performing formulation was further exposed to the following four artificial ageing methods: initial debonding, 24 h water storage, one-month water storage, and one-month acid challenge. A field-emission scanning electron microscope (FE-SEM) was used to examine the integrity of debonded enamel surfaces and calcium-phosphates (CaPs) reprecipitation.

Results

The best-performing formulation (7% nHAp-SEP) resulted in significantly lower SBS (p < 0.001) than the control SEP following the four artificial ageing methods. Nevertheless, it survived the ageing protocols and yielded clinically acceptable SBS with the advantages of leaving minimal adhesive residue, preserving enamel integrity and smoothness, and inducing CaP reprecipitation as confirmed by FE-SEM images.

Conclusions

A newly developed SEP produced adequate orthodontic bond strengths and left unblemished debonded enamel surfaces with minimal remnant adhesive and remineralisation potential, thereby suggesting simpler and safer bonding/debonding procedures.

Development of a remineralizing calcium phosphate nanoparticle-containing self-etching system for orthodontic bonding

Objectives

This study aimed to incorporate hydroxyapatite nanoparticles (nHA) or amorphous calcium phosphate nanoparticles (nACP) into a self-etch primer (SEP) to develop a simplified orthodontic bonding system with remineralizing and enamel preserving properties.

Materials and Methods

nHA and nACP were incorporated into a commercial SEP (Transbond™ plus) in 7% weight ratio and compared with the plain SEP as a control. Shear bond strengths (SBS), enamel damage, and adhesive remnant index (ARI) scores were evaluated at 24 h and post 5000 thermocycling. Field-emission scanning electron microscope (FESEM) was used to inspect the distribution of the nanoparticles in the experimental SEPs and evaluate the enamel surface integrity both before bracket bonding and post bracket debonding. Phase determination and remineralizing capability of the modified SEP were characterized by X-ray diffraction and Raman spectroscopy, respectively.

Results

The addition of nHA or nACP to the SEP significantly reduced the SBS, ARI, and enamel damage (p < 0.05) as compared to the control SEP; however, only nHA-SEP survived the thermocycling protocol and yielded acceptable SBS (13.38 MPa). Enamel remineralizing ability of the developed nHA-SEP was confirmed by both FESEM images and Raman phosphate map.

Conclusions

Incorporating nHA into SEP resulted in clinically acceptable bond strengths with remineralizing ability.

Clinical relevance

The newly developed nHA-SEP has unprecedented ability to simultaneously etch, prime, and remineralize the enamel in a single step leaving immaculate enamel surface with the potential of saving cost and time at the post-debonding step.

RESIN INFILTRATION MAY BE A FEASIBLE OPTION TO ESTHETICALLY MASK ENAMEL WHITE SPOT LESIONS

ARTICLE TITLE AND BIBLIOGRAPHIC INFORMATION

Bourouni S, Dritsas K, Kloukos D, Wierichs RJ. Efficacy of resin infiltration to mask post-orthodontic or non-post-orthodontic white spot lesions or fluorosis - a systematic review and meta-analysis. Clin Oral Investig. 2021 Aug;25(8):4711-4719.

SOURCE OF FUNDING

University of Bern.

TYPE OF STUDY/DESIGN

Systematic review with meta-analysis.

Protocol for the development of a Core Outcome Set for trials on the prevention and treatment of Orthodontically induced enamel White Spot Lesions (COS-OWSL)

BACKGROUND

Enamel white spot lesions (WSLs), characterized by an opaque, matt, and chalky white appearance of enamel, are a sign of incipient caries. WSLs are common in orthodontic practice and can affect both the oral health and dental aesthetics of patients. Extensive studies have been conducted to evaluate the effectiveness of prevention or treatment for orthodontically induced enamel WSLs. However, substantial heterogeneity has been found in the outcomes used for the prevention and treatment of WSLs in literature, which prevents researchers from comparing and combining the results of different studies to draw more decisive conclusions. Therefore, we aim to develop a Core Outcome Set for trials on the prevention and treatment of Orthodontically induced enamel White Spot Lesions (COS-OWSL).

METHODS

The development of COS-OWSL comprises four phases: (1) a scoping review to identify and summarize all existing outcomes that have been used in trials on the prevention or treatment of orthodontically induced WSLs; (2) qualitative interviews with orthodontic patients without (for prevention) and with WSL-affected teeth (for treatment) and relevant dental professionals to identify additional outcomes relevant to them; (3) Delphi surveys to collect opinions from key stakeholders including patients, dental professionals, and researchers and to reach a preliminary consensus; and (4) a consensus meeting to develop the final COS-OWSL.

DISCUSSION

The COS-OWSL will be developed to facilitate the synthesis of evidence regarding the prevention and treatment of orthodontically induced WSLs and to promote the consistent use of relevant patient-important outcomes among future studies in this field.

TRIAL REGISTRATION

Core Outcome Measures in Effectiveness Trials (COMET) initiative (the COS-WSL project) 1399.