Er:YAG laser application in caries removal and cavity preparation in children: a meta-analysis

Efficacy of non-surgical laser therapy for the management of peri-implantitis: A systematic review and meta-analysis

OBJECTIVE

This systematic review and meta-analysis aimed to evaluate the efficacy of non-surgical laser therapies compared to other treatment modalities for managing peri-implantitis and to analyze post-treatment outcomes of different interventions.

DATA AND SOURCES

A comprehensive search was conducted across Medline (PubMed), Web of Science, and the Cochrane Central Register of Controlled Trials (CENTRAL), identifying 4675 studies published between January 1953 and November 2023.

STUDY SELECTION

A total of 15 randomized controlled trials (RCTs) involving 540 patients and 658 implants met the inclusion criteria, with 10 studies eligible for meta-analyses. Meta-analyses revealed that Er:YAG laser therapy significantly reduced bleeding on probing (BOP) by 35.6 % (95 % CI: 17.3 % to 53.9 %; I2 = 83 %) and probing depth (PD) by 0.65 mm (95 % CI: 0.33 to 0.97; I2 = 0 %). The combination of mechanical debridement (MD) and Er,Cr:YSGG laser therapy improved PD by 1.23 mm (95 % CI: 0.76 to 1.70; I2 = 0 %) and reduced BOP by 47.3 % (95 % CI: 38.4 % to 56.1 %; I2 = 0 %). However, none of the therapies showed any significant advantage in preventing crestal bone loss (CBL). Laser therapies did not demonstrate any significant superiority over traditional therapies (p > 0.05).

CONCLUSIONS

Non-surgical laser therapies, including Er:YAG, Er,Cr:YSGG, Nd:YAG and diode lasers, demonstrated effectiveness in reducing inflammation and probing depths but did not consistently outperform MD alone or in combination with other treatments. The findings emphasize the need for further research and standardized protocols, as no modality significantly prevented CBL. These results provide evidence-based insights into optimizing non-surgical management strategies for peri-implantitis.

CLINICAL SIGNIFICANCE

Non-surgical laser therapies demonstrate significant reductions in inflammation and probing depths in peri-implantitis treatment. However, their comparable outcomes to mechanical debridement highlight the need for further studies to establish their role and develop standardized protocols for optimized clinical use.

Advanced Lasers and Their Applications in Dentistry

The development of laser technology has revolutionized dentistry, offering complementary and alternative approaches to traditional techniques. Lasers have been successfully integrated into various dental procedures, enhancing treatment outcomes and patient care. Several types of lasers can increase the acid resistance of enamel, thus preventing caries. Laser fluorescence has been utilized for the pre-operative diagnosis of dental caries, enabling early detection and effective treatment planning. The therapeutic application of lasers in caries treatment aligns with the contemporary philosophy of minimally invasive procedures. Clinicians can use laser Doppler flowmetry as a supplementary tool for pulp vitality testing by detecting pulpal blood flow. Lasers are also employed in various pulp-related interventions, such as managing dentine hypersensitivity and performing root canal therapy. These procedures benefit from the precision and reduced invasiveness provided by laser technology. Furthermore, laser fluorescence serves as an additional tool for subgingival calculus detection. High-power and low-power lasers are used in both nonsurgical and surgical therapies to treat periodontal and peri-implant diseases, oral mucosa conditions, and even cancer based on their specific properties. Lasers are also utilized to accelerate bone regeneration, promote adhesive strength, and remove ceramic brackets. In summary, laser technology has significantly impacted contemporary dentistry by facilitating early diagnosis, minimally invasive treatments, and precise operative procedures, ultimately improving patient outcomes and expanding the scope of dental practice.

The application of lasers in vital pulp therapy: clinical and radiographic outcomes

The main purpose of vital pulp therapy (VPT) is to preserve the integrity and function of the pulp. A wide variety of materials and techniques have been proposed to improve treatment outcomes, and among them, the utilization of lasers has gained significant attention. The application of lasers in different stages of VPT has witnessed remarkable growth in recent years, surpassing previous approaches.This study aimed to review the applications of lasers in different steps of VPT and evaluate associated clinical and radiographic outcomes. An electronic search using Scopus, MEDLINE, Web of Science and Google Scholar databases from 2000 to 2023 was carried out by two independent researchers. The focus was on human studies that examined the clinical and/or radiographic effects of different laser types in VPT. A total of 4243 studies were included in this narrative review article. Based on the compiled data, it can be concluded that although current literature suggests laser may be proposed as an adjunct modality for some procedural steps in VPT, more research with standardized methodologies and criteria is needed to obtain more reliable and conclusive results.

In vitro effect of Er: YAG laser irradiation in caries cavity preparation on biobehaviors of adjacent human dental pulp cells in the pulp chamber

The erbium-doped yttrium aluminum garnet (Er: YAG) laser has been successfully applied in caries removal; however, little is known about proper parameters of Er: YAG laser on different conditions of caries removal, especially the influence of Er: YAG irradiation on human dental pulp cells (hDPCs). Here, we tested the effects of Er: YAG laser at different output energy levels (100, 200, 300, 400, and 500 mJ) on biobehaviors of hDPCs. To simulate clinical deep caries conditions, hDPCs were cultured on the pulpal side of 500-μm-thick dentin disks in an in vitro pulp chamber model. Temperature change, structural change, and ablation depth of dentin disk were also recorded. The findings suggested that the biological behaviors of hDPCs are strongly correlated with the energy output of the Er: YAG laser. Er: YAG laser irradiation at 100 mJ may be proper and safe for deep caries removal since it would not cause any adverse effect on hDPCs biobehaviors.

Chemical and morphological analysis of dentin irradiated by different high-power lasers: a systematic review

PURPOSE

This systematic review provides an overview of the main chemical and morphological alterations generated on dentin by different high-power lasers' irradiation.

METHODS

The review was registered in PROSPERO (CRD42023394164) and PRISMA guidelines were followed. The search strategy was conducted on MEDLINE (PubMed), Embase (Elsevier), and Web of Science (Clarivate) databases. The eligibility criteria were established according to the PICOS strategy, focusing on in vitro and ex vivo studies that assessed the chemical and morphological changes in dentin using five high-power lasers: Nd:YAG (1064 nm), Er:YAG (2940 nm), Er, Cr:YSGG (2780 nm), diode (980 nm), and CO2 (10,600 nm). Publication range was from 2010 to 2022. Data was summarized in tables and risk of bias was assessed by QUIN tool.

RESULTS

The search resulted in 2255 matches and 57 studies composed the sample. The methods most used to assess the outcomes were scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), and Raman. The studies presented "medium" and "low" risk of bias. The laser prevalently identified was the Er:YAG laser, associated with dentin ablation, absence of smear layer, and exposed tubules. The Nd:YAG laser generated vitreous surface and thermal damage, such as carbonization and cracks. The other lasers caused an irregular surface and no adverse thermal effects. Regarding the chemical structure, only the Er,Cr:YSGG laser caused collagen matrix reduction. The effects found were more intense with higher dosimetry.

CONCLUSION

Evidence available indicates that the irradiation of dentin with high-power lasers are related to morphological outcomes favorable to adhesive restorative procedures, with minimal changes in collagen matrix and mineral content. However, those observations should be carried carefully by clinicians and more clinical trials regarding the association of high-power laser irradiation and restorative procedure longevity are needed.

Er:YAG laser in selective caries removal and dentin treatment with chitosan: a randomized clinical trial in primary molars

This study evaluated the effect of chitosan on dentin treatment after selective removal of caries lesions with Er:YAG laser in reducing Streptococcus mutans, as well as its effect on the performed restorations. The sample consisted of children (aged 7 to 9 years) with active carious lesions and dentin cavitation located on the occlusal surface of deciduous molars. Eighty teeth were randomly distributed into 4 groups according to the caries removal method: Er:YAG laser (250 mJ/4 Hz) or bur and dentin surface treatment: 2.5% chitosan solution or distilled water. The bacterial load of caries-affected dentin was quantified by counting CFU/mg (n = 10). The teeth were restored and evaluated at 7 days, 6 months, and 12 months using modified USPHS criteria (n = 20). Microbiological data was analyzed by Mann-Whitney and clinical analyses were done using Kruskal-Wallis and Dunn test (α = 0.05). The results showed that the Er:YAG laser significantly reduced the amount of Streptococcus mutans (p = 0.0068). After dentin treatment with chitosan, there was a significant reduction in the amount of Streptococcus mutans for both removal methods (p = 0.0424). For the retention and secondary caries criteria, no significant differences were observed along the evaluated time (p > 0.05). The laser-treated group was rated "bravo" for discoloration (p = 0.0089) and marginal adaptation (p = 0.0003) after 6 and 12 months compared to baseline. The Er:YAG laser reduced the amount of Streptococcus mutans and the chitosan showed an additional antibacterial effect. After 1 year, the Er:YAG laser-prepared teeth, regardless of the dentin treatment, showed greater discoloration and marginal adaptation of the restorations.

Effect of viscosity of experimental universal adhesive on bond strength to dentin prepared with Er:YAG laser

The aim of this study was to clarify the effect of universal adhesive (UA) viscosity on the bond strength of resin composite to dentin prepared with Er:YAG laser. Four experimental UAs (SI-1, SI-2, SI-3, and SI-4) were developed by adding 1, 2, 3, and 4 wt/% nanosilica to BeautyBond Xtreme (Shofu), respectively. BeautyBond Xtreme was used as a control (SI-0). The viscosities of experimental UAs were measured using a B-type viscometer. After bovine mandibular anterior teeth were ground with #600 emery paper to obtain the flattened dentin surfaces, the dentin surfaces were cut thinly by irradiating the Er:YAG laser. Specimens were prepared using the respective UA and flowable resin composite and subjected to the microtensile bond strength (µTBS) test. The data from viscosity measurement and the μTBS test were statistically analyzed using the Kruskal-Wallis test. The mean values of viscosity significantly differed among the all experimental groups (p < 0.01). The μTBS of SI-1 and SI-2 was significantly higher than that of SI-0, SI-3, and SI-4 (p < 0.001). The μTBS of SI-0 was significantly lower than that of SI-4 (p < 0.001). The viscosities of the experimental universal adhesives significantly affected their bond strength to laser-cut dentin.

Bond strength of bulk fill composite to teeth prepared with Er

Aim: The present in vitro study aimed to evaluate the bond strength of a bulk fill composite on dentin surfaces prepared with the Er: YAG laser. Methods: Twenty-four permanent third molars were selected and divided into 2 groups: CP - Conventional preparation with high-speed handpiece (control) and LA (laser) - Preparation with Er: YAG laser. The occlusal surface was removed to expose coronal dentin, which was subsequently prepared with a high-speed handpiece or Er: YAG laser (350mJ, 4Hz, 1.5 ml/min water flow). Both groups were restored with Filtek One Bulk Fill (3M ESPE) composite resin. After 24 hours, the samples were evaluated for microtensile bond strength (μTBS), fracture pattern, and scanning electron microscopy (SEM). Results: The data obtained in the μTBS test were submitted to t-test (α=0.05). The results showed no difference in μTBS when the different types of cavity preparation were compared (ρ=0.091). Fracture patterns revealed the prevalence of cohesive fracture in composite resin in CP (83.3%) and adhesive fracture in LA (92.1%). In the SEM analysis, the LA group demonstrated the presence of gaps between the composite resin and the irradiated dentin surface. The hybrid layer exhibited more regularity with the presence of longer and uniform resin tags in the CP group. Conclusion: The type of cavity preparation did not influence the values of bulk fill composite resin μTBS to dentin. Fracture patterns and scanning electron microscopy analyses suggested less interference at the adhesive interface in preparations performed using CP.

The impact of Er:YAG laser combined with fluoride treatment on the supragingival plaque microbiome in children with multiple caries: a dynamic study

BACKGROUND

As a minimally invasive tool for caries prevention tool, the pulsed erbium:yttrium-aluminum-garnet (Er:YAG) laser is being used in a large number of studies. Microorganisms are extremely vital in the occurrence and development of dental caries. However, the impact of Er:YAG laser irradiation combined with fluoride on the dynamic microbial changes that occur in dental plaques is still uncertain. In this study, we examined the effect of an Er:YAG laser combined with fluorine on supragingival microbial composition and diversity in children with multiple caries.

METHODS

In this study, dental plaque samples (n = 48) were collected from 12 children with over 8 filled teeth. Supragingival plaques from left mandibular molars before (CB) and after fluoride treatment (CA) and right mandibular molars before (EB) and after fluoride+Er:YAG laser treatment (EA) were collected from each patient. In CB and EB groups, the samples were collected just before the treatments. In CA and EA groups, the samples were collected 1 month after treatments. Then, all specimens were subjected to 16S rRNA high-throughput sequencing to investigate the changes in microbial composition and diversity in mandibular molar supragingival plaques before and after fluoride or fluoride+Er:YAG laser treatment.

RESULTS

The dental plaque microbial diversity was higher in the EA group than in the EB group (baseline levels), and the microbial composition changed in EA group compared with EB group (P < 0.05). The levels of microorganisms associated with caries occurrence, including Proteobacteria, Fusobacteria, and Bacteroidetes, declined, while the levels of Faecacterium, Fastidiosipila, Vibrio, and Shewanella increased in EA group compared with EB group. The declines in Firmicutes, Streptococcus, Fusobacterium, and Veillonella levels were significantly lower in the EA group than in the CA group.

CONCLUSION

The combined application of the Er:YAG laser and fluoride may be more effective than using fluoride alone in reducing the proportion of cariogenic bacteria, increasing the diversity of plaque microorganisms, and further promoting the microecological balance.

Effect of erbium family laser etching on shear bond strength of enamel surfaces: A meta-analysis-PRISMA

BACKGROUND

Recently, laser etching has appealed to people's attention. It is meaningful to compare the effect of erbium-doped yttrium-aluminum-garnet (Er:YAG) and erbium-chromium; yttrium-scandium-gallium-garnet (Er,Cr:YSSG) laser etching parameters with acid etching on bond strength of enamel surfaces. As far as we know, there still remains no related meta-analysis. To evaluate the efficacy of Er:YAG and Er,Cr:YSSG lasers etching on shear bond strength (SBS) of brackets bonded to enamel. The meta-analysis was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses, conducted with literature search.

METHODS

Twelve relevant randomized controlled trials (RCTs) were included.

RESULTS

The pooled analysis of SBS showed that there were no significant differences between erbium family lasers and acid etching. In the mass, we noticed they did not achieve statistical significance in the lasers etching and acid etching. However, pooled analysis of 5 studies showed the SBS bonding to enamel was lower in Er,Cr:YAG laser group compared with acid group. As a whole, there were statistical significance between erbium lasers groups and acid etching group in adhesive remnant index (ARI) aspects, which less adhesives remained can reduce damage to enamel. With regard to the rate of teeth with ARI score ≤2, the results in Er:YAG laser etching group were obviously higher than acid etching group.

CONCLUSION

Our data indicated that erbium lasers may be considered bonding of brackets to enamel instead of acid etching bonding to enamel.

Efficiency of ER:YAG laser therapy in combination with behaviour management technique in reducing anxiety among paediatric dental patients - a study protocol for a randomised clinical trial

INTRODUCTION

When providing dental care to children with a high level of dental anxiety, the range of approaches is divided into two sections: use of behaviour management techniques (BMTs) and application of alternative methods for caries removal. In an attempt to reduce dental anxiety, they can be mixed and matched in accordance with the dentists' choice. Owing to its promoted advantages, erbium-doped yttrium aluminium garnet (Er:YAG) laser turns into an ideal alternative technique for hard dental tissue therapy in anxious paediatric patients. The aim of the study is to assess the efficacy of a modified version of the BMT 'Latent inhibition' in combination with Er:YAG laser for achieving a reduction of dental anxiety in paediatric dental patients.

METHODS AND ANALYSIS

This is a protocol for a randomised controlled clinical trial. The participants will be children aged 6-9 years, requiring conservative treatment of occlusal carious lesion on a second primary molar. Patients will be randomly assigned to the experimental or control group via a computer-generated sequence. In both groups, 'Latent inhibition' will be used as an anxiety-management technique. In the experimental group, caries treatment will be performed with Er:YAG laser, whereas that in the control group it will be performed with conventional rotary instruments. Outcome measures will be dental anxiety felt before and after the treatment, reported by the patient on a modified version of the Faces Scale by LeBaron et al., and the dynamics of heart rate, registered during the treatment session, which will be measured with a mobile pulse oximeter. Data will be analysed by independent sample t-test and paired t-test (p˂0.05).

ETHICS AND DISSEMINATION

The study protocol has been approved by the Committee for Scientific Research Ethics, Medical University-Plovdiv, Bulgaria (reference number P-2839, protocol of approval number 3/30.04.2015) and registered on a publicly accessible database. This research received institutional funding from the Medical University-Plovdiv, Bulgaria. The results will be presented through peer-reviewed publications and conference presentations.

TRIAL REGISTRATION NUMBER

NCT04924452.

Effect of green tea-loaded chitosan nanoparticles on leathery dentin microhardness

The purpose of this study was to assess the effect of a chitosan-based nanoformulation containing green tea on leathery (remaining) dentin subsurface microhardness. Size distribution, polydispersity index (PDI) and zeta potential (mV) of nanoformulations were previously determined by dynamic light scattering (DLS). Human dentin specimens were exposed to Streptococcus mutans for 14 d. Soft dentin were selectively removed by Er:YAG laser (n = 30) or bur (n = 30). Remaining dentin was biomodified with chitosan nanoparticles (Nchi, n = 10) or green tea-loaded chitosan nanoparticles (Gt + Nchi, n = 10) for 1 min. Control group (n = 10) did not receive any treatment. Subsurface microhardness (Knoop) was evaluated in hard (sound) and soft dentin, and then, in leathery dentin and after its biomodification, at depths of 30, 60 and 90 μm from the surface. Nchi reached an average size of ≤ 300 nm, PDI varied between 0.311 and 0.422, and zeta potential around + 30 mV. Gt + Nchi reached an average size of ≤ 350 nm, PDI < 0.45, and zeta potential around + 40 mV. Soft dentin showed significantly reduced microhardness at all depths (p > 0.05). The subsurface microhardness was independent of choice of excavation method (p > 0.05). At 30 µm from the surface, Gt + Nchi increased the leathery dentin microhardness compared to untreated group (p < 0.05). Nchi promoted intermediate values (p > 0.05). Both nanoformulations showed an average size less than 350 nm with nanoparticles of different sizes and stability along the 90-day period evaluated. Subsurface microhardness of bur-treated and laser-irradiated dentin was similar. At 30 µm, the biomodification with Gt + Nchi improved the microhardness of leathery dentin, independently of caries excavation method used.

Use of the Er:YAG Laser in Conservative Dentistry: Evaluation of the Microbial Population in Carious Lesions

The aim of this study is to investigate the Erbium:Yttrio-Aluminum-Granate (Er:YAG) laser photothermal and mechanical effects on cariogenic species concentration and on the microbial load composition of therapeutic cavities, in order to evaluate the possible micro-organisms reduction and make a comparison with manual and rotating conventional therapy (CT). A clinical trial was designed, including adults with active deep carious lesions on permanent teeth who were divided into two groups, i.e., control group and intervention group treated with CT and Er:YAG therapy, respectively. Before and after any conservative treatment, two oral samples were collected using a small sterile microbrush scrubbed within the base of the dentinal cavity tissue. The percentage of reduction and the colony-forming units (CFUs) count after Er:YAG and conventional treatments were compared for total microorganisms, including Candida spp., Streptococcus spp., and Lactobacillus spp. The microbial reduction varied from 90.2% to 100% and was significantly observed for total microorganisms and Streptococcus spp. (p < 0.05). The Er:YAG laser shows the potential for clinical applications, especially with paediatric and complicated patients, thanks to its minimally invasive properties and its effect on the reduction of microbial load.

Optical coherence tomography characterizes the roughness and thickness of the heterogeneous layer on cortical bone surface induced by Er:YAG laser ablation at different moisture contents

Background

As an innovative bone ablation tool, pulsed erbium: yttrium-aluminum-garnet (Er:YAG) laser is being used in clinical practice. It faces the same problems as traditional tools: the water content of bone usually changes with the position, while the amount of water spray in the process of laser irradiation is also uncertain. Real-time monitoring of the effects of laser bone ablation is necessary, but effective tools are still lacking. In this study, we examined the feasibility of rapidly and non-destructively evaluating the surface properties of bone after Er:YAG laser irradiation at different moisture contents by optical coherence tomography (OCT).

Methods

Bone specimens (n=90) collected from pig cortical bone were used in this study. All bone specimens had similar volume and surface characteristics after machining. To display the baseline level before Er:YAG laser ablation, a control group (n=10) without dehydration or Er:YAG laser ablation was examined with OCT, scanning electron microscopy (SEM), and energy dispersive X-ray (EDX) spectroscopy. The remaining specimens were randomly divided into four groups (n=20/group) with different moisture content: dried (Group 2 and Group 4) or not dried (Group 1 and Group 3). Pulsed Er:YAG laser (120 mJ/pulse, 20 Hz, 100 µs) was used for perpendicular irradiation with (Group 1 and Group 2) or without (Group 3 and Group 4) water spray. The treated specimens were subjected to SEM, EDX spectroscopy, OCT, and then processed for histological evaluation.

Results

After Er:YAG laser ablation, the melting effect was obvious in the SEM results of the dry groups and non-sprayed groups (Groups 2-4). EDX spectroscopy showed that the content of calcium and phosphorus and their ratios remained unchanged in the undried and with water spray group (Group 1) were the closest to the control group. Three-dimensional (3D) OCT could evaluate the depth and shape of ablation grooves. The roughness of the laser-ablated surface could be visualized by extracting the surface lines from cross-sectional OCT images. The results illustrated that the laser ablation with water spray could achieve a smoother surface. Furthermore, OCT results demonstrated that a layer with high image intensity was generated on the bone surface after laser irradiation. The thickness of these layers showed a correlation with whether or not the laser irradiation was sprayed with water. Histology showed that thin eosin-stained layers were created in all experimental groups, which matched well with OCT results of the layers with high image intensity. No denatured layer was observed in the non-irradiated areas of bone tissues.

Conclusions

OCT could rapidly and non-destructively visualize the bone surface before and after Er:YAG laser ablation at four different moisture contents. The morphology of ablation grooves, as well as the roughness and thickness of the heterogeneous layer on the bone surface, could be characterized quantitatively with good correlation with SEM and histology. This study will promote the development of OCT as an efficient and accurate tool for evaluating laser ablation of bone.