Caries removal in deciduous teeth using an Er:YAG laser: a randomized split-mouth clinical trial

Restoration Integrity in Primary Teeth Prepared Using Erbium/Yttrium-Aluminum-Garnet Laser: A Randomized Split-Mouth Clinical Study

The most frequently used and universally accepted technique for removing caries is mechanical ablation of decayed tissues by rotating drills. New minimally invasive strategies, such as the use of lasers to perform highly controlled tissue ablation, have been introduced in dental practice. The aim of this study was to assess and compare treatment with a 2940 nm erbium/yttrium-aluminum-garnet (Er:YAG) laser versus a conventional rotary treatment during cavity preparation in children with regard to restoration integrity. In a randomized, controlled, blinded trial using a split-mouth design, 40 (9-12-year-old) children with 80 carious primary molars were included. The cavity in one quadrant was randomized to be treated conventionally using a bur, while the cavity in the other quadrant was prepared using an Er:YAG laser. At the one-year follow-up, clinical examinations were conducted to assess the integrity of the restorations according to the Ryge criteria. The data were analyzed using SPSS version 22 (IBM Inc., Chicago, IL, USA). The average age of the participants was 9.4 ± 1.29 years. Males accounted for 51.4% of the participants. The Ryge criteria showed clinical success of restorations, and there was no discernible difference between the conventional and laser intervention techniques. Over one year, no statistically significant differences in the clinical integrity based on the Ryge criteria were found following class I cavity preparation in primary teeth with either procedure.

Interventions for treating cavitated or dentine carious lesions

BACKGROUND

Traditionally, cavitated carious lesions and those extending into dentine have been treated by 'complete' removal of carious tissue, i.e. non-selective removal and conventional restoration (CR). Alternative strategies for managing cavitated or dentine carious lesions remove less or none of the carious tissue and include selective carious tissue removal (or selective excavation (SE)), stepwise carious tissue removal (SW), sealing carious lesions using sealant materials, sealing using preformed metal crowns (Hall Technique, HT), and non-restorative cavity control (NRCC).

OBJECTIVES

To determine the comparative effectiveness of interventions (CR, SE, SW, sealing of carious lesions using sealant materials or preformed metal crowns (HT), or NRCC) to treat carious lesions conventionally considered to require restorations (cavitated or micro-cavitated lesions, or occlusal lesions that are clinically non-cavitated but clinically/radiographically extend into dentine) in primary or permanent teeth with vital (sensitive) pulps.

SEARCH METHODS

An information specialist searched four bibliographic databases to 21 July 2020 and used additional search methods to identify published, unpublished and ongoing studies.  SELECTION CRITERIA: We included randomised clinical trials comparing different levels of carious tissue removal, as listed above, against each other, placebo, or no treatment. Participants had permanent or primary teeth (or both), and vital pulps (i.e. no irreversible pulpitis/pulp necrosis), and carious lesions conventionally considered to need a restoration (i.e. cavitated lesions, or non- or micro-cavitated lesions radiographically extending into dentine). The primary outcome was failure, a composite measure of pulp exposure, endodontic therapy, tooth extraction, and restorative complications (including resealing of sealed lesions).

DATA COLLECTION AND ANALYSIS

Pairs of review authors independently screened search results, extracted data, and assessed the risk of bias in the studies and the overall certainty of the evidence using GRADE criteria. We measured treatment effects through analysing dichotomous outcomes (presence/absence of complications) and expressing them as odds ratios (OR) with 95% confidence intervals (CI). For failure in the subgroup of deep lesions, we used network meta-analysis to assess and rank the relative effectiveness of different interventions.

MAIN RESULTS

We included 27 studies with 3350 participants and 4195 teeth/lesions, which were conducted in 11 countries and published between 1977 and 2020. Twenty-four studies used a parallel-group design and three were split-mouth. Two studies included adults only, 20 included children/adolescents only and five included both. Ten studies evaluated permanent teeth, 16 evaluated primary teeth and one evaluated both. Three studies treated non-cavitated lesions; 12 treated cavitated, deep lesions, and 12 treated cavitated but not deep lesions or lesions of varying depth.  Seventeen studies compared conventional treatment (CR) with a less invasive treatment: SE (8), SW (4), two HT (2), sealing with sealant materials (4) and NRCC (1). Other comparisons were: SE versus HT (2); SE versus SW (4); SE versus sealing  with sealant materials (2); sealant materials versus no sealing (2).  Follow-up times varied from no follow-up (pulp exposure during treatment) to 120 months, the most common being 12 to 24 months. All studies were at overall high risk of bias. Effect of interventions Sealing using sealants versus other interventions for non-cavitated or cavitated but not deep lesions There was insufficient evidence of a difference between sealing with sealants and CR (OR 5.00, 95% CI 0.51 to 49.27; 1 study, 41 teeth, permanent teeth, cavitated), sealing versus SE (OR 3.11, 95% CI 0.11 to 85.52; 2 studies, 82 primary teeth, cavitated) or sealing versus no treatment (OR 0.05, 95% CI 0.00 to 2.71; 2 studies, 103 permanent teeth, non-cavitated), but we assessed all as very low-certainty evidence. HT, CR, SE, NRCC for cavitated, but not deep lesions in primary teeth The odds of failure may be higher for CR than HT (OR 8.35, 95% CI 3.73 to 18.68; 2 studies, 249 teeth; low-certainty evidence) and lower for HT than NRCC (OR 0.19, 95% CI 0.05 to 0.74; 1 study, 84 teeth, very low-certainty evidence). There was insufficient evidence of a difference between SE versus HT (OR 8.94, 95% CI 0.57 to 139.67; 2 studies, 586 teeth) or CR versus NRCC (OR 1.16, 95% CI 0.50 to 2.71; 1 study, 102 teeth), both very low-certainty evidence. CR, SE, SW for deep lesions The odds of failure were higher for CR than SW in permanent teeth (OR 2.06, 95% CI 1.34 to 3.17; 3 studies, 398 teeth; moderate-certainty evidence), but not primary teeth (OR 2.43, 95% CI 0.65 to 9.12; 1 study, 63 teeth; very low-certainty evidence). The odds of failure may be higher for CR than SE in permanent teeth (OR 11.32, 95% CI 1.97 to 65.02; 2 studies, 179 teeth) and primary teeth (OR 4.43, 95% CI 1.04 to 18.77; 4 studies, 265 teeth), both very low-certainty evidence. Notably, two studies compared CR versus SE in cavitated, but not deep lesions, with insufficient evidence of a difference in outcome (OR 0.62, 95% CI 0.21 to 1.88; 204 teeth; very low-certainty evidence). The odds of failure were higher for SW than SE in permanent teeth (OR 2.25, 95% CI 1.33 to 3.82; 3 studies, 371 teeth; moderate-certainty evidence), but not primary teeth (OR 2.05, 95% CI 0.49 to 8.62; 2 studies, 126 teeth; very low-certainty evidence). For deep lesions, a network meta-analysis showed the probability of failure to be greatest for CR compared with SE, SW and HT.

AUTHORS' CONCLUSIONS

Compared with CR, there were lower numbers of failures with HT and SE in the primary dentition, and with SE and SW in the permanent dentition. Most studies showed high risk of bias and limited precision of estimates due to small sample size and typically limited numbers of failures, resulting in assessments of low or very low certainty of evidence for most comparisons.

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.

Efficacy and Patient's Acceptance of Alternative Methods for Caries Removal-a Systematic Review

Dental caries is a disease of dental hard tissues, considered the most common non-communicable disease worldwide. Conventional treatments for caries removal are often associated with pain and fear, so different therapeutic approaches have been developed towards more conservative and pleasant treatments. This systematic review aimed to assess the efficacy and patient's acceptance of alternative methods for caries removal compared to conventional methods. The Cochrane Library, Embase, Medline/Pubmed, Web of Science, and Clinical Trials databases were searched. Clinical trials of primary dental caries treated with alternative methods were included. The last search was performed on 5 August 2020. The Population, Intervention, Comparison, and Outcome (PICO) strategy was followed. Thirty-seven clinical trials were included, reporting caries removal using alternative (chemomechanical-Brix 3000, Carie-care, Carisolv and Papacarie, laser-Er:YAG (Erbium-doped Yttrium Aluminium Garnet) and Er,Cr:YSGG (Erbium, Chromium-doped Yttrium, Scandium, Gallium and Garnet), and a system combining air and sono-abrasion-Vector^® System) and conventional methods. Alternative methods tended to prolong treatment time and lessen anesthesia need. All treatments were effective in reducing cariogenic flora, and the restoration's performance did not differ significantly. Chemomechanical solutions seemed to be the best option towards minimally invasive treatments, with good control during application and action and good treatment experiences for patients. Papacarie was demonstrated to be an effective method for caries removal with less pain, and superior acceptance by patients when compared to conventional treatments.

Does Er,Cr:YSGG reduce the microleakage of restorations when used for cavity preparation? A systematic review and meta-analysis

Background

As the member of erbium laser family, Erbium, Chromium: Yttrium Scandium Gallium Garnet (Er,Cr:YSGG) has obtained the approval for caries removal and cavity preparation by Food and Drug Administration (FDA). However, there is still controversy over the beneficial effects of Er,Cr:YSGG preparations on microleakage. The present study is the first systematic review and meta-analysis to compare the microleakage of cavities prepared by Er,Cr:YSGG lasers with that by traditional burs. In addition, the effect of acid etching on the adhesive potential of self-etch and etch-and-rinse adhesives was assessed after laser preparation.

Methods

An electronic search was performed in Pubmed, EBSCO, Embase, and the Cochrane Controlled Register of Trials (CENTRAL).

Results

Totally, 357 articles were identified. Finally, 13 met the inclusion criteria, of which 11 were selected for meta-analysis. All the included studies exhibited a moderate risk of bias. Based on the meta-analysis, no significant difference was observed between the Er,Cr:YSGG and traditional bur groups in terms of the incidence of microleakage. Self-etch adhesives, in combination with prior acid etching, showed less microleakage than those without acid etching in the laser-prepared cavities.

Conclusions

Current studies do not support the beneficial effects of Er,Cr:YSGG preparations on microleakage. Additional acid etching with self-etching adhesives is recommended after Er,Cr:YSGG preparations. Further high-quality studies are needed to draw a convincing conclusion in the future.

Four-year clinical prospective follow-up of resin composite restoration after selective caries removal using Er:YAG laser

OBJECTIVES

The aim of this study was to longitudinally evaluate, after a 4-year period, the clinical longevity of composite resin restoration compared to the baseline, after selective caries removal in permanent molars using Er:YAG laser or bur preparation with biomodification of dentin with the use of chlorhexidine.

METHODS

Selective caries removal was performed on 80 teeth of 20 individuals who each had at least four active carious lesions. These lesions, located on occlusal surfaces of permanent molar counterparts, were removed using (i) Er:YAG laser biomodified with chlorhexidine, (ii) Er:YAG laser and application of deionized water, (iii) bur preparation biomodified with chlorhexidine, and (iv) bur preparation and application of deionized water. At the end of 4 years, 64 of the 80 restorations were evaluated in 16 individuals (n = 16). The restorations were evaluated, both clinically and photographically, using scanning electron microscopy (SEM) and pulp vitality analysis. The experimental data were statistically evaluated by kappa, Fisher's, and chi-square tests, with a significance level of 5%. The Kaplan-Meier test and the Cox regression analysis were used to evaluate the survival of the restorations.

RESULTS

After 4 years of follow-up, there was a statistically significant difference in marginal discoloration criteria for all of the groups evaluated. For marginal adaptation criteria, there was a statistically significant difference for the Er:YAG laser group biomodified with chlorhexine (p = 0.050). For clinical and radiographic evaluation of pulp vitality, there were no statistically significant differences among the groups (p = 0.806).

CONCLUSION

Er:YAG laser can be used for selective caries removal, regardless of dentin biomodification with chlorhexidine or application of deionized water, once it produced promising results in composite resin restorations after 4 years of follow-up, according to the criteria evaluated. The selective caries removal using Er:YAG laser or bur and the biomodification of dentin with the use of chlorhexidine did not influence the survival of composite resin restorations after the 4-year follow-up period.

CLINICAL RELEVANCE

Composite resin restorations applied after selective caries removal using Er:YAG laser or burs, regardless of dentin biomodification with the use of chlorhexidine or application of deionized water, showed adequate clinical behavior after 4 years of follow-up.

Comparison of the micro-tensile bond strengths of four different universal adhesives to caries-affected dentin after ER:YAG laser irradiation

The micro-tensile bond strengths (micro-TBSs) of four universal adhesive systems, applied in two different bonding techniques, to carries-affected dentin after Er:YAG laser irradiation were investigated. Twenty-four extracted human molars were divided into four groups, according to the adhesive systems used. Each group was subdivided into two subgroups, depending on the bonding method used: the etch-and-rinse procedure or self-etch procedure. The carious lesions were irradiated using an Er:YAG laser. Resin composites were used to restore the adhesive-treated dentin surfaces. After 2,500 thermal cycles, the vertical composite resin-dentin sticks obtained were subjected to micro-TBS tests. One tooth in each group was examined using scanning electron microscopy (SEM). There were statistically significant differences (p<0.001) in micro-TBS values between universal adhesives. The results of this study suggested that universal adhesives applied both with self and total etch technique can be used for adhesive restorations to caries-affected dentin after Er:YAG laser irradiation. If lasers are preferred as a caries removal method, choosing a dentin bonding agent containing MDP may be recommended in clinical practice due to the property of increasing the bonding strength.

Selective Removal of Necrotic Dentin in Primary Teeth Using Laser Irradiation: One-Year Clinical Evaluation of Composite Restorations

Introduction: This study aimed to evaluate the child's salivary cortisol levels, clinical performance and marginal adaptation of restorations after selective removal of necrotic dentin in primary teeth using Er: YAG laser irradiation. Methods: A double-blind clinical study was performed in children at 7-10 years. Children who had at least 2 teeth with carious lesions involving the occlusal and proximal surfaces of primary molars counterparts were selected. Removal of necrotic dentin was performed by 2 methods: Er: YAG laser irradiation and bur-preparation. Cortisol levels (n =24) was evaluated by ELISA. Clinical analysis (n =20) was performed after the restorations polish, 6 and 12 months after restorative procedure using United States Public Health Service (USPHS) method and photographs. Scanning electron microscopy (SEM) was used to analyz the marginal gap formation (n =20). The analysis of the data was performed by 95% confidence interval, Shapiro-Wilk test, Friedman and Wilcoxon post hoc tests (α =5%). Results: Cortisol levels were higher during selective removal of necrotic dentin, regardless of the method used (P>0.05). After 12 months, there was no evidence of the difference in the restorations performed on cavities prepared by both methods. SEM analysis revealed that the laser-irradiated teeth showed 10% of gaps in the full extent of restoration. For bur-prepared teeth, 20% of gaps were found at the cavosurface margin. Conclusion: The salivary cortisol levels on children that received Er: YAG laser irradiation for removal the necrotic dentin was similar to the control group. Class II restorations evaluated after 1 year period did not suffer interference by the use of Er: YAG laser irradiation.

Comparison of Er,Cr:YSGG Laser Handpieces for Class II Preparation and Microleakage of Silorane- or Methacrylate-Based Composite Restorations

OBJECTIVE

The aim of this study was to evaluate the influence of cavity preparation with different Er,Cr:YSGG laser handpieces on microleakage of different posterior composite restorations.

METHODS

Fifty-four extracted intact human premolars were randomly assigned to three groups according to cavity preparation method: Bur Group: high-speed diamond bur (Diatech), MD Group: Er,Cr:YSGG laser Waterlase MD handpiece (Biolase Millennium II), and Turbo Group: Er,Cr:YSGG laser Waterlase MD TURBO handpiece (Biolase Millennium II). One hundred eight Class II slot cavities were prepared on the mesial and distal proximal surfaces of each tooth, and the cavity preparation times required were determined. The groups were then subdivided according to the restorative systems used (n = 12): a conventional methacrylate-based microhybrid composite (Filtek P60+Adper Single Bond 2/3M); a silorane-based resin composite (Filtek Silorane+Silorane System Adhesive/3M); and a nanohybrid methacrylate-based composite (Kalore+G-Bond/GC). The restorative systems were applied according to the manufacturers' recommendations. Following thermocycling (X5000; 5°C-55°C), the teeth were coated with nail varnish except the restoration margins, immersed in 0.5% basic fuchsin dye solution, and sectioned in a mesiodistal direction. Dye penetration was evaluated under a light microscope for occlusal and cervical margins. Data were analyzed with one-way ANOVA and chi-square tests (p < 0.05).

RESULTS

The cavity preparation time (mean ± SD) required for Bur, MD, and Turbo group was 31.25 ± 3.82, 222.94 ± 15.85, and 92.5 ± 7.42 sec, respectively, and the differences among the groups were statistically significant (p < 0.05). Comparing the occlusal and cervical microleakage scores, no statistically significant differences were found among the groups and subgroups (p > 0.05).

CONCLUSIONS

Er;Cr:YSGG laser cavity preparation with the Turbo handpiece needed shorter time than the MD handpiece, although it needed longer time than the conventional diamond bur. The use of different handpieces of Er,Cr:YSGG laser did not differ from conventional preparation with diamond bur in terms of microleakage with the tested methacrylate- and silorane-based posterior composite restorative systems.

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

The aim of this meta-analysis was to systematically evaluate the applications of Er:YAG lasers for the removal of caries and cavity preparation in children. The meta-analysis was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) and was conducted with data extracted from seven relevant randomized controlled trials (RCTs) published from 1997 to July 2017. The data heterogeneity of each study was assessed by a Q test. We used the heterogeneity results to calculate the standard mean difference (SMD) or relative risk (RR) and 95% confidence interval (95%CI) using STATA version 10.0. The publication bias was evaluated using Begger's test. There were seven randomized controlled trials included in this study. The analysis results indicate that compared to the conventional mechanical method, more time was needed for Er:YAG laser treatment (SMD 1.945, 95%CI 0.942 to 2.948). However, the pain reported by patients was reduced with Er:YAG laser treatment (SMD - 1.013, 95%CI - 1.892 to - 0.196). There were no significant differences between the groups in the complete retention rate (RR 1.021, 95%CI 0.963 to 1.114), the marginal discoloration (RR 1.638, 95% CI 0.240 to 11.986) and the marginal adaptation (RR 1.480, 95%CI 0.257 to 8.515). In conclusion, our data indicate that the time required for Er:YAG laser treatment was longer than that for the conventional mechanical method, but there was less pain associated with the Er:YAG laser treatment. There were no significant differences in the complete retention rate, marginal discoloration, and marginal adaptation between the two groups.

A Randomized Controlled Trial Comparing Er:YAG Laser and Rotary Bur in the Excavation of Caries - Patients' Experiences and the Quality of Composite Restoration

Objective

The aim of this study was to evaluate patients´ experiences of two excavation methods, Er:YAG laser and rotary bur and time required by the methods as well as objective assessments of quality and durability of restorations over a two-year period.

Methods

A prospective, single-blind, randomized and controlled investigation was performed. Patients aged 15 to 40 years with at least two primary caries lesions, which had been radiographically assessed as of the same size, were recruited. In each patient, one cavity was excavated using rotary bur and one using Er:YAG laser technique. The time required for excavations and, where applicable, local anaesthesia, was measured during the treatments. Patient experiences were measured using questionnaires. The quality and durability of restorations were assessed over a two-year period in accordance with modified Ryges criteria and radiographs. Twenty-five patients (mean age 22.6 years) participated in the study. In total, 56 cavities were included of which 28 were treated with Er:YAG laser and 28 were treated with a rotary bur.

Results

The patients associated the laser method with less discomfort. The mean time for excavation by laser was three times longer than by rotary bur (13.2 min vs. 4.3 min, P<0.0001). Over a two-year period, no statistically significant differences with regard to quality or durability could be seen between the restorations associated with the methods.

Conclusion

The Er:YAG laser technique was more time-consuming than the rotary bur. Despite this, the laser technique caused less discomfort and was preferred as an excavation method by patients.

Efficacy of removal of cariogenic bacteria and carious dentin by ablation using different modes of Er:YAG lasers

The primary objective of this in vitro study was to evaluate the efficiency of removal of cariogenic bacteria and carious dentin by ablation using two lasers: fluorescence-feedback controlled (FFC) Er:YAG laser and different pulses of Er:YAG laser based on variable square pulse technology (VSPt). The secondary objective was to measure the temperature during laser ablation of carious tissue. Seventy-two extracted human molars were used in this study. Sixty teeth with carious dentin were randomly divided into four experimental groups according to the treatment for caries removal: group 1: 400 µs (FFC group); group 2: super short pulse (SSP group, 50 µs pulse); group 3: medium short pulse (MSP group, 100 µs pulse); group 4: short pulse (SP group, 300 µs pulse) and one positive control group with no treatment. Twelve teeth without carious lesion were used as a negative control group. After caries removal, swabs were taken with cotton pellets and real-time PCR analysis was performed. During caries ablation, a thermal infrared camera was used to measure the temperature changes. In all experimental groups, specimens were free of bacterial contamination after the treatment. In the SSP, MSP and SP groups, temperatures measured during caries ablation were significantly higher compared to temperatures in the FFC group (P<0.001). In this in vitro study, laser treatment for removal of carious dentin and cariogenic bacteria was an efficient treatment modality without causing excessive temperatures that might adversely affect pulp vitality.

Selective removal of carious lesion with Er:YAG laser followed by dentin biomodification with chitosan

The aim of this study was to evaluate the effect of Er:YAG laser for selective removal of carious lesion, followed by biomodification with chitosan gel where the subsurface microhardness, chemical composition, and morphological changes of the residual caries-affected dentin were examined. Artificial dentinal lesions were created by pH-cycling method (14 days) in 104 bovine specimens (5 × 5 mm). Specimens were randomly divided according to the carious removal method: bur (low-speed handpiece) or Er:YAG laser (250 mJ/4 Hz). Specimens were treated with 35% phosphoric acid and were subdivided into two groups according to dentin biomodification: without chitosan (control) and 2.5% chitosan. Forty specimens were restored with an adhesive system and composite resin. Subsurface microhardness tests were performed in sound dentin, caries-affected dentin, residual caries-affected dentin, and after the restoration. The other 64 specimens were subjected to SEM-EDS atomic analysis. Data were statistically analyzed (p < 0.05). After the Er:YAG laser excavation, the microhardness value of residual caries-affected dentin was higher (p < 0.05) than bur-treated dentin. A significant decrease in the amount of Ca, P, and Ca/P ratio was found after the removal of carious lesions with Er:YAG laser (p < 0.05). The biomodification with chitosan did not influence the microhardness and atomic percentage of Ca, P, and Ca/P ratio of residual caries-affected dentin (p > 0.05). SEM analysis showed morphological changes on residual caries-affected dentin (p > 0.05). The selective removal of carious dentin with Er:YAG laser increased microhardness of residual caries-affected dentin, changing its surface morphology and chemical composition. The biomodification with chitosan did not influence the structural and chemical composition of residual caries-affected dentin.

Effect of Er:Yag laser on dentin demineralization around restorations

The aim of this study was to evaluate the effect of cavity preparation with Er:YAG laser on dentin adjacent to restorations submitted to cariogenic challenge in situ, by subsuperficial microhardness analysis. Bovine incisors were sectioned, flattened, and polished, resulting in 40 dentin slabs. The slabs were randomly assigned to four groups (n = 10), according to the cavity preparation method: I-high-speed handpiece (control); II-Er:YAG laser (160 mJ; 3 Hz); III-Er:YAG laser (260 mJ; 3 Hz); IV-Er:YAG laser (300 mJ; 3Hz). Cavities were restored with composite resin, and the specimens were fixed in intra-oral appliances, which were worn by 10 volunteers for 14 days for simulating cariogenic challenge in situ. During the experimental period, 20% sucrose solution was dripped over each specimen 6 times a day. Samples were removed, sectioned, and examined for subsuperficial Knoop microhardness at 100, 200, and 300 μm from the restoration and at 30 μm from dentin surface. Split-plot analysis of variance showed no significant difference among the cavity preparation techniques (p = 0.1129), among distances (p = 0.9030), as well as no difference in the interaction between the main factors (p = 0.7338). It was concluded that the cavity preparation with Er:YAG laser did not influence on dentin microhardness submitted to cariogenic challenge in situ.

Clinical evaluation of composite restorations in Er:YAG laser-prepared cavities re-wetting with chlorhexidine

OBJECTIVES

The objective of this study was to evaluate longitudinally the composite restorations, performed in cavities prepared by Er:YAG or conventional bur, and dentin re-wetting with water or chlorhexidine.

MATERIALS AND METHODS

Twenty individuals with four active caries with cavitation reaching the dentin located on the occlusal surface of molars counterparts are selected. The teeth of each individual were randomly assigned into four groups: (I) Er:YAG laser (260 mJ/4 Hz) re-wetting with chlorhexidine, (II) Er:YAG laser (260 mJ/4 Hz) re-wetting with deionized water, (III) conventional method re-wetting with chlorhexidine, and (IV) conventional method re-wetting with deionized water. The teeth were isolated, prepared cavities, phosphoric acid etching, and re-wetting according to previously assigned method. Restoration was performed employing the Single Bond 2 and Z350XT resin. Clinical follow-up was held after the polishing of the restoration (baseline) and 6 and 12 months of the making of the restoration using the modified USPHS criteria. The restorations were qualitatively analyzed by means of photographs. In the evaluation period, replicas of the restorations were analyzed by SEM. Data were analyzed by statistics using chi-square test (p < 0.05).

RESULTS

After 12 months of clinical evaluation, groups prepared with laser and re-wetting with chlorhexidine and water showed the lowest marginal staining value. There was no statistical difference between the groups for other factors. SEM analysis revealed that a non-expressive amount of restorations showed gaps and irregularities of tooth-restoration interface after 6 and 12 months compared to the baseline.

CONCLUSION

The restorations performed in laser-prepared cavities, regardless of the re-wetting, presented the best clinical performance over the evaluated period.

CLINICAL RELEVANCE

Laser-prepared teeth, regardless of re-wetting, showed greater resistance to marginal discoloration.