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International Dental Journal logoLink to International Dental Journal
. 2024 Feb 20;74(4):679–687. doi: 10.1016/j.identj.2024.01.022

Effect of Er:YAG Laser Irradiation on Preventing Enamel Caries: A Systematic Review and Meta-Analysis

Zhiyuan Feng a,⁎, Rui Yuan b, Lin Cheng c, Hao Fan b, Minmin Si b, Zhaonan Hao b
PMCID: PMC11287166  PMID: 38383278

Abstract

Caries is a global health problem, and its prevention has become a main goal of modern dentistry. Laser irradiation is believed to have potential in preventing dental caries. The purpose of this systematic review and meta-analysis was to evaluate whether Er:YAG laser irradiation has the potential to prevent enamel caries. Based on inclusion and exclusion criteria, PubMed, Web of Science, and EMBASE databases were searched; 2 reviewers independently used these search strategies to review titles and abstracts, with no language or date restrictions, up to June 2023. For the quantitative analysis, continuous variables were analysed by standard mean difference (SMD) with a 95% confidence interval (CI). The statistical analyses were conducted using Review Manager and Cochrane Collaboration (2020). A total of 51 potentially eligible studies were identified, of which 16 in vitro studies were eventually included in the quantitative meta-analysis. Three studies showed a low risk of bias, and 13 studies a medium risk of bias. In general, there was no significant difference between the calcium ions released under acidic conditions after laser irradiation. The final results indicated that after Er:YAG laser irradiation, enamel could maintain higher surface microhardness in acidic environments, as well as smaller lesion depth and less mineral loss, revealing its potential in preventing enamel caries. However, the effect of laser irradiation on the release of calcium ions in acidic solutions and the surface microhardness of demineralised enamel was not significant. Therefore, more in vitro and clinical trials are needed in to evaluate whether Er:YAG laser irradiation can effectively prevent enamel caries in clinical settings.

Key words: Er:YAG laser, Enamel demineralisation, Caries, Prevention, In vitro, Meta-analysis

Introduction

Caries is a global health problem, and its prevention has become a main goal of modern dentistry. The pathogenesis of caries is mainly the result of cariogenic bacteria in oral plaque biofilm fermenting carbohydrates, producing organic acids, and reducing the local pH to a critical value, which lead to tooth demineralisation.1 During demineralisation, these acids dissolve the main mineral component of the enamel - hydroxyapatite crystals(Ca10(PO4)6(OH)2), and minerals such as calcium and phosphate diffuse out of the tooth. When a sufficient amount of mineral is lost, the lesion appears clinically as a white spot, which is the initial manifestation of enamel caries,2 and if this process continues, cavities will eventually develop.3

The traditional methods of preventing dental caries include the application of sealants on the enamel pits and fissures of molar teeth4 as well as the topical use of fluoride.5 However, fluoride-containing products have shown poor protective effects on pit and fissure caries.3 The incorporation of fluoride into hydroxyapatite to inhibit caries is still controversial, as its effectiveness has been found to be related to its continuous availability in saliva and dental plaque.6 The sustainable supply of fluoride in the mouth depends on whether the patient engages in regular oral hygiene measures. Therefore, caries prevention methods that are not solely dependent on the patient are needed. Laser technology has emerged as a promising avenue for caries prophylaxis, and there have been published reviews on this topic.7 In order to evaluate whether laser technology has the potential to prevent dental caries under in vitro experimental conditions, quantitative analytical methods can be used, including quantification of mineral loss, determination of calcium solubility, and determination of calcium content in tooth enamel surface and demineralising solution.8

It is essential to choose a laser that can be strongly and efficiently absorbed by the enamel and converted into heat without causing damage to the surrounding tissue to prevent tooth demineralisation.9 The effectiveness of the laser treatment largely relies on the absorption of specific wavelengths by the targeted tissues.10 Therefore, the laser must be selected based on the efficient absorption of wavelengths by the hard tissue components of the teeth. Commonly used lasers for preventing enamel caries include argon ion lasers, Er,Cr: YSGG lasers, Er:YAG lasers, Nd:YAG lasers, carbon dioxide lasers, and semiconductor lasers.9

Amongst these, the Er:YAG laser is particularly notable, as it operates at a wavelength of 2.94 μm, which corresponds to the maximum absorption peak of water and hydroxyl radicals present in hydroxyapatite.11 Consequently, the strong absorption of this laser leads to thermal changes in the tooth enamel, potentially causing chemical or morphologic structural alterations and ablation of hard tissue.12 Because Er:YAG has the advantage of interaction with the hard tissue of teeth, its preventive effect on caries has also been widely studied by scholars. And it is not only the use of laser alone but also the combination of Er:YAG laser and some anticaries agents—such as fluoride, tricalcium phosphate (Ca3PO4), titanium tetrafluoride (TiF4), Tooth Mousse (CPP-ACP), and NovaMin (bioactive glass)—being used to assess whether there is a synergistic effect between laser and anticaries agents.13 In addition, the use of laser etching before the bonding of brackets whilst preventing caries is also a promising application.14

However, current research on laser caries prevention has produced conflicting results, resulting in a lack of consensus amongst scholars.15,16 In addition, there is a dearth of published quantitative data synthesis on the efficacy of Er:YAG laser in caries prevention. Therefore, we have undertaken a systematic review and meta-analysis of the published in vitro studies to assess whether Er:YAG laser irradiation has the potential to prevent enamel caries. Our aim is to provide preliminary evidence for clinicians and researchers in this field.

Materials and methods

Protocol

This systematic review was conducted and reported according to Cochrane Handbook for Systematic Reviews of Interventions17 and the PRISMA statement.18 This systematic review was registered with PROSPERO (CRD42023441638).

Eligibility criteria

The criteria for inclusion and exclusion of studies were determined according to PICOS principles. The inclusion criteria were as follows: (1) Participants: human teeth with intact enamel and no defects, microcracks, caries, restorations, or developmental lesions. (2) Intervention: Er:YAG laser irradiation. (3) Comparison: the control group did not receive any anticaries intervention. (4) Outcome: solubility of calcium ions in solution, enamel surface microhardness, mineral loss, and demineralised lesion depth. (5) Study design: in vitro studies. The exclusion criteria were as follows: (1) Not human teeth such as: bovine teeth; human teeth are tested not on enamel, but on dentin or the root of tooth (2) Other lasers used to illuminate the enamel. (3) In vivo studies, case reports, reviews, or abstracts.

Search strategy

In order to clarify the effect of the Er:YAG laser on caries prevention, the following 3 databases were searched: PubMed, Web of Science, and EMBASE. The following keywords were searched to screen for possible eligible studies based on a combination of specific medical subject headings (MeSH) and free-text terms for these 3 databases: (Erbium-doped: Yttrium-Aluminium Garnet laser OR Er: YAG laser) AND (dental caries [MeSH Terms] OR caries OR tooth decay OR enamel demineralization OR enamel remineralization). An additional search of the gray literature was performed using Google Scholar and OpenGrey, with descriptors for “dental caries” AND “ER:YAG laser”. The list of references for included studies was manually searched to screen for articles not found in the databases that might meet the inclusion criteria. The most published journals related to this topic in the past 5 years were manually searched (Journal of Dentistry, Journal of Lasers in Medical Sciences, Lasers in Medical Science, BMC Oral Health, Dental Research, Journal Angle Orthodontist). Two reviewers independently used these search strategies to review the title and abstract, with no language and date restrictions, up to June 2023.

Study selection

The retrieved studies were initially screened based on their titles and abstracts. Duplicated and irrelevant studies were removed, and the full texts of potentially interesting studies were reevaluated. Only studies that met the inclusion criteria were included. Two reviewers independently conducted this process, and any inconsistencies were resolved by discussing them with another author to reach a consensus on inclusion of the article.

Data extraction

An Excel data extraction table was established to summarise the following research characteristics: (1) the name of the first author; (2) the publication date; (3) the type of human tooth; (4) the number of teeth per group; (5) parameters of Er:YAG laser irradiation in studies; (6) outcome assessment method; and (7) outcome variables (mean values and standard deviations). Two reviewers completed this work independently and repeatedly.

Assessments of the risk of bias

For the included in vitro studies, the bias risk assessment was based on and adapted from the judgment model of in vitro trial bias risk assessment proposed in previous systematic reviews.19 The following 6 items are reviewed in the article: randomisation of samples, quality check of samples, sample-size calculation, details of laser parameters used, blinding of operator, and operator training. If the research met the criteria, the paper received a “Yes”; if no relevant information could be found, the paper was marked with a “No.” The risk of bias in the included trials was independently conducted by 2 authors. Any disagreements between reviewers were discussed by consulting with the third author until agreement was reached, if needed. The risk of bias was classified according to the sum of the “yes” answers received: 1 to 3 = high risk of bias, 4 to 5 = moderate risk of bias, and 6 to 8 = low risk of bias.

Statistical analysis

Quantitative analysis was conducted using Review Manager (Version 5.4; Rev Man) and Cochrane Collaboration 2020. The data type of the result indicator is mainly continuous variable. The standardised mean differences (SMDs) were used with 95% confidence intervals (CIs) to summarise the therapeutic effect of each study. Forest plots were used for meta-analysis. Statistical significance was defined as P ≤ .05 (Z test), and heterogeneity was assessed with I2.20 I2 ranges from 0% to 100%; 25%, 50%, and 75% values represent low, moderate, and high heterogeneity, respectively. If the included studies showed low heterogeneity, a fixed-effect model was used. When the clinical and methodological heterogeneity were high or I2 >50%, random effects models were used to combine the studies.21

Results

Literature search

Based on this study's retrieval strategy, a total of 777 articles were initially obtained via a literature search in the 3 databases, and 259 duplicates were removed. The titles and abstracts of the remaining 518 records were screened; the full text of 51 articles that might meet the requirements was then evaluated. Through manual retrieval and query of grey literature, no studies meeting the inclusion criteria could be found. Finally, 16 trials were included for meta-analysis. The specific PRISMA flowchart is shown in Figure 1.

Fig. 1.

Fig 1

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Prisma flow diagram.

Characteristics of the included studies

Table 1 shows the details of the included studies. These studies were published from 2003 to 2022. Two trials were performed on human deciduous teeth, whilst the rest of the articles utilised permanent teeth. As for the design scheme of the experiments, 2 studies used laser irradiation after enamel demineralisation, whilst the remaining experiments subjected sound enamel to laser irradiation followed by an acid challenge.

Table 1.

Characteristics of the included studies.

Author (year) Type of human tooth Cariogenic challenge Outcome assessment method Parameters of the Er:YAG laser
Fluence (J/cm2) Pulse energy (mJ) Frequency (Hz) Pulse duration (μs) Irradiation time (s) Cooling Beam diameter (mm)
Castellan et al 200722 Deciduous first molar teeth sound enamel pH/cycling pH 4.6/7.0, 5 d Mineral loss by microhardness testing 40.3 60 2 - - - 0.32
Ceballos-Jiménez et al 201823 Unerupted third molars sound enamel pH 4.8, 24 h Calcium ions released 12.7 100 10 250–400 20 Water 1
Cecchini et al 200515 Nonerupted third molars sound enamel pH 4.5, 8 h Calcium ions released 33.3 60 2 - - Water 0.63
44.4 80 2 - - 0.63
66.6 120 2 - - 0.63
20 64 2 - - 0.32
29.9 86.4 2 - - 0.32
42.2 135 2 - - 0.32
Correa-Afonso et al 201024 Posterior teeth sound enamel pH/cycling pH 4.6/7.0, 10 d Lesion depth - 80 2 250–500 20 Water (with or without) -
Delbem et al 200325 Third molar teeth sound enamel pH/cycling pH 4.3/7.0, 10 d Surface microhardness 0.95 60 1 250–500 10 Without 0.63
Díaz-Monroy et al 201426 Bicuspid teeth sound enamel pH 4.8, 24 h Calcium ions released 12.7 25.5 38.2 100 200 300 10 250–400 15 Without 1
Contreras-Bulnes et al 202216 Deciduous molars sound enamel pH 4.8, 24 h Surface microhardness 7.5 100 7 400 13 Water 1.3
Calcium ions released 12.7 1
Liu et al 200627 Molars sound enamel pH/cycling pH 4.5/7.0, 2 d Lesion depth 12.7 100 - - 4 Without 1
25.5 200
38.2 300
Mathew et al 201328 Unerupted third molars sound enamel pH 4.5, 24 h Calcium ions released 12.7 100 10 250–400 20 Water 1
Moura et al 202129 Third molars demineralised enamel Enamel was irradiated by laser after demineralisation Surface microhardness 1.49 20 10 - 60 Water 1.3
2.95 50
Nair et al 201630 Premolars sound enamel pH 4.5, 24 h Calcium ions released - 200 7 - 30 Without -
Polat et al 202013 Wisdom teeth sound enamel pH/cycling pH 4.3/7.0, 9 d Surface microhardness - 80 10 1000 30 Air and water 1.3
Yassaei et al 202031 Premolars demineralised enamel Enamel was irradiated by laser after demineralisation Surface microhardness - 100 10 - 5 Air and water 0.9
Yassaei et al 201432 Premolars sound enamel pH/cycling pH 4.3/7.0, 12 d Mineral loss by microhardness testing - 80 4 - 10 Water 1.2
Liu et al 201333 Premolars sound enamel pH/cycling pH 4.5/7.0, 4 d Mineral loss by micro-CT 2.0 - 2 100 5 Without 0.5
Lesion-depth 5.1
Liu et al 201334 Premolars sound enamel pH/cycling pH 4.5/7.0, 4 d Mineral loss by micro-CT 5.1 100 5 100 5 Without 0.5
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“-” indicates “not available.”

Micro-CT, micro–computed tomography.

To evaluate the effectiveness of caries prevention, 6 studies analysed the calcium ions in solution15,16,23,26,28,30; of these studies, 3 utilised different laser usage parameters, with one study using 6 different fluences,15 another using 3 fluences,26 and one using 2 fluences.16 Five investigations compared the enamel surface microhardness, with 3 articles using sound enamel13,16,25 and one of them using 2 different types of laser fluence.16 Additionally, 2 articles used enamel that had undergone demineralisation,29,31 with one of them using 2 different laser fluences.29 For the evaluation of mineral loss, 2 studies utilised microhardness testing22,32 and 2 utilised micro–computed tomography (micro-CT).33,34 Furthermore, 3 studies compared lesion depth,24,27,33 with one of the studies employing 3 different fluences for the laser setup27 and another using 2 different fluences.33 The specific laser usage parameters are also detailed in Table 1.

Assessments of the risk of bias

The risk of bias in the 16 studies is shown in Table 2. Three studies showed a low risk of bias, and 13 studies presented a medium risk of bias.

Table 2.

Assessments of the risk of bias.

Authors, year Randomisation of samples Quality check of samples Sample-size calculation Details of laser parameters used Blinding of operator Operator training Total score Risk of bias
Castellan et al 200722 Y Y N Y Y N 4 Medium
Ceballos-Jiménez et al 201823 Y Y N Y Y N 4 Medium
Cecchini et al 200515 Y Y N Y Y N 4 Medium
Correa-Afonso et al 201024 Y N N Y Y N 3 Medium
Delbem et al 200325 Y Y N Y Y N 4 Medium
Díaz-Monroy et al 201426 N Y N Y Y N 3 Medium
Contreras-Bulnes et al 202216 Y Y N Y Y Y 5 Low
Liu et al 200627 Y Y N Y Y N 4 Medium
Mathew et al 201328 Y Y N Y Y Y 5 Low
Moura et al 202129 Y N N Y Y Y 4 Medium
Nair et al 201630 Y N N Y Y Y 4 Medium
Polat et al 202013 N Y N Y Y Y 4 Medium
Yassaei et al 202031 Y Y N Y Y Y 5 Low
Yassaei et al 201432 Y N N Y Y Y 4 Medium
Liu et al 201333 N N N Y Y Y 3 Medium
Liu et al 201334 N N N Y Y Y 3 Medium
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Total score: 1–2, high, 3–4, medium, and 5–6, low risk of bias.

Data synthesis and meta-analysis

Surface microhardness

Figure 2A compares the tooth surface microhardness values of the laser group with those of the control group. For the use of sound enamel surface, the final combined results showed that after laser irradiation, the enamel surface microhardness was higher than that of the control group (SMD = 2.41; 95% CI, 0.70–4.12; P = .006). However, for enamel surfaces that have undergone demineralisation, results showed that there was no statistical difference between the enamel surface microhardness after laser irradiation and the control group (SMD = 0.66; 95% CI, −1.12 to 2.44; P = .47).

Fig. 2.

Fig 2

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A, Surface microhardness. B, Mineral loss.

Mineral loss

Figure 2B summarises the findings of the meta-analysis comparing the effect of laser and control on mineral loss. The overall standardised mean difference in the meta‐analysis was −2.09 (95% CI, −3.29 to −0.88; P = .0007). Figure 2A shows a Forest plot comparing caries prevention effects between laser and control groups using surface microhardness values. Figure 2B shows a Forest plot comparing caries prevention effect between laser and control groups on mineral loss.

Lesion depth

Figure 3A illustrates the comparison of depth of lesion. Three studies provided the value of enamel lesion depth under acid challenge to evaluate the effect of laser caries prevention. The results of meta-analysis showed that the depth of lesion in the enamel after laser irradiation was smaller under the condition of acid invasion, and the results were statistically significant (SMD = −0.55; 95% CI, −0.97 to 0.12; P = .01).

Fig. 3.

Fig 3

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A, Forest plot comparing caries prevention effect between laser and control groups using lesion depth value. B, Forest plot comparing the efficacy in laser and control groups using calcium ions released.

Calcium ions released

For the experimental group with different laser parameters set in the same study, we compared all of them with the control group. In the end, a total of 10 comparisons were made on 6 studies. Figure 3B illustrates a meta-analysis of calcium ions released by enamel in an acidic solution after laser irradiation vs a control group without any treatment. The overall standardised mean difference was −0.40, with a 95% CI, −0.96 to 0.15; P = .15. The results indicated that there was no significant difference between the calcium ions released under acidic conditions after laser irradiation and the control group.

Discussion

The purpose of this systematic review and meta-analysis was to evaluate whether Er:YAG laser irradiation has the potential to prevent enamel caries in in vitro studies. We summarised in vitro data on the efficacy of Er:YAG laser irradiation in preventing dental caries compared to without laser treatment. Since the observational indicators used in the 16 trials were not exactly the same, we discussed them separately in the analysis and summary of the subsequent data. For a study evaluating multiple laser parameters, we extracted the single sample size, mean value, and standard deviation for each condition.

The microhardness test can provide information about the physical properties of the enamel surface and is an effective method to measure changes in dental hard structure (mineral loss or gain). It has been used to measure the effects of demineralisation and remineralisation.35 When combining the results of enamel surface microhardness, 2 studies used laser irradiation on demineralised enamel surfaces, which is a treatment design for early enamel lesions. Different from the other 3 reports that used the experimental design method of intact enamel accepting the acid challenge, we conducted subgroup analysis on demineralised enamel. The results showed that laser irradiation did not significantly increase surface microhardness in the treatment of early lesions compared to the control group. This may be related to the lack of further acid challenge after laser irradiation. Laser irradiation may have a greater effect on the solubility of enamel under acid attack; if there is no acid condition, laser irradiation will not further increase the mineral content. However, after acid stimulation, the sound enamel showed greater surface microhardness values compared to the non-irradiated control group, and the results were statistically significant. This may be due to the changes in the surface enamel structure caused by the laser, making it more resistant to mineral loss.25

The occurrence of caries usually begins beneath the surface of the enamel. When evaluating the process of demineralisation and remineralisation of lesions under the surface layer, the cross-sectional microhardness test (CSMH) can be used to measure the hardness changes from the surface to the deep enamel, and the hardness values at different parts’ depth can be converted into volume percentage mineral and the relative mineral loss of each specimen can be calculated.32 Micro-CT can obtain 3D images and analyse mineral density in detail without damaging tissue, which is a promising method for evaluating demineralisation or remineralisation.36

Polarised light measurements are a highly sensitive technique for detecting changes in hard tissues and can provide quantitative information on the pore volume (porosity) in demineralised and remineralised enamel as well as lesion characteristics.35 The demineralisation and normal areas of tooth samples can be clearly distinguished, and the remineralisation can be qualitatively evaluated.37 The enamel samples were prepared into thin sections and examined under a polarising microscope, which can accurately measure the depth of demineralised lesions.35 The mineral loss and lesion depth reflect the mineral content under the surface of the enamel, and the final combined result is statistically significant, indicating that the enamel is more resistant to acid dissolution after laser irradiation. This may be related to the following factors11: (1) Decreased carbonate and crystalline water content. The content of carbonate will affect the sensitivity of enamel to demineralisation because it fits less well in the lattice and therefore produces a less stable and more acid-soluble apatite phase.38 Ultrastructural changes: the decomposition of the organic matrix and an increase in OH, changes in the crystallinity of the enamel.39 The ion diffusion pathway is blocked and the ion diffusion rate is reduced. (2) Changes in physical morphology that increase the acid resistance of enamel.40 (3) Improvement of crystal planes and formation of new crystallographic phases.41,42

The solubility of enamel under acid attack can be assessed by measuring the amount of calcium ions released in the acidic solution after exposure to Er:YAG laser. The combined data showed that there was no statistical difference in the amount of calcium ions released into the acidic solution after laser irradiation compared with the control group. This evaluation is inconsistent with the results of the other 3 evaluation measures that laser can prevent caries. The inconsistency may be attributed to the use of different models for enamel demineralisation: simple acid challenge vs pH cycle, which simulates the dynamic cycle of demineralisation and remineralisation in the oral environment. Laser irradiation can promote the formation of microspaces on the enamel surface, and some scholars believe that these microspaces can be used as areas for ion deposition, thus enhancing enamel remineralisation.15 When laser-irradiated enamel is challenged by acid, these microspaces facilitate the release of calcium and phosphorus plasma from the tooth structure. However, due to the failure to receive the deposition of calcium and phosphorus ions contained in neutral solution under pH cycle conditions, the advantage of microspaces formed after laser irradiation to promote ion deposition is lost, which is reflected in the result that laser irradiation fails to enhance the acid resistance of enamel.

The effect of laser irradiation on preventing dental caries was reported as early as 1966.43 However, because the true mechanism of laser caries prevention is still unclear, more detection methods need to be explored in the future to clarify its true mechanism of action. At the same time, we also found that there was significant heterogeneity amongst the various indicators in the summary. Therefore, we should exercise caution in interpreting the results. There are many reasons for heterogeneity, such as variations in laser parameters (pulse energy, fluence, pulse width, irradiation mode, power, water/air irrigation, irradiation time, distance from tooth surface, temperature rise).

Different energy settings were used for laser irradiation in the included literature, and the use of higher energy may lead to the ablation or formation of deeper and wider spaces in the enamel structure, resulting in more mineral loss in acidic solutions.15 In the process of laser irradiation, accompaniment by water cooling is also an important factor. Ceballos-Jiménez et al23 used laser irradiation with an energy density of 12.7 J/cm with water cooling, and enamel did not reflect obvious acid resistance. Contrary to the results, Díaz-Monroy et al26 showed more acid-resistant dissolution in the process of laser irradiation with the same flow density without water cooling; Cecchini et al15 also found that lower-energy Er:YAG laser irradiation can reduce the solubility of tooth enamel without seriously altering tooth structure, even under the cooling effect of water flow.

Temperature rise is an important factor to consider in the process of laser irradiation. When enamel was heated, the acid resistance increased from 100 ℃ to 200 ℃ but decreased again between 300 °C and 400 °C.27 The subablative parameter used by Liu et al33 induces heating of the enamel surface below 300 °C may preserve the organic matrix, which is necessary to reduce the permeability of the enamel. However, there are very limited reports on temperature in the included literature.

In addition, the optical properties of the hard tissue of the tooth may be changed by the different arrangement of the enamel columns in the enamel and the non-uniformity of the chemical composition. Differences in the optical properties of the enamel itself, such as scattering, absorption coefficient, refractive index, thermal conductivity, and thermal relaxation time also affect the experimental results.44 Although the experimental samples included in our study are all human enamel, they belong to different parts of the teeth, and the enamel itself can vary.

In the future, it will be necessary to further clarify the laser parameter settings when using Er:YAG laser irradiation for caries prevention. Additionally, more detection methods for demineralisation and remineralisation need to be explored in order to elucidate the true mechanism of laser irradiation to prevent caries. Furthermore, more clinical trials are needed to evaluate the safety and effectiveness of lasers.

Limitations

One of the limitations of this systematic review and meta-analysis is that all the included studies were in vitro studies, which cannot fully simulate the conditions in the oral environment. Furthermore, because dental caries is a multifactorial disease mainly caused by bacteria, the articles included in this study only address the chemical-induced demineralisation of enamel, lacking the important influence of bacteria in the caries process. Future studies should aim to simulate the oral environment in order to validate the results of the current systematic review and obtain clinically relevant information.

Conclusions

This study comprehensively analysed the potential of Er:YAG laser irradiation in preventing enamel caries under in vitro conditions by including different measurement indicators. The final results indicated that after Er:YAG laser irradiation, enamel could maintain higher surface microhardness in acidic environments, as well as smaller lesion depth and mineral loss, showed potential in preventing enamel caries. However, the effect of laser irradiation on the release of calcium ions in acidic solutions and the surface microhardness of demineralised enamel was not significant. Therefore, more in vitro and clinical trials are needed in the future to evaluate whether Er:YAG laser irradiation can effectively prevent the occurrence of enamel caries in clinical settings.

Conflict of interest

None disclosed.

Acknowledgments

Author contributions

Conceptualisation: LC, RY, and ZF. Methodology: HF and MS. Software: ZH. Resources: RY and MS. Writing–original draft preparation: LC and RY. Writing–review and editing: LC and ZF. Revision: ZF and RY. All authors read and approved the final manuscript.

Funding

This study was funded by Natural Science Research General Program of Shanxi Province No. 202103021224371. Funded the medical writing assistance.

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