Effect of acid etching and different Er:YAG laser procedures on microleakage of three different fissure sealants in primary teeth after aging

Evaluation of flexural strength, degree of conversion, and demineralization-prevention properties in adjacent tooth structures of an experimental fissure sealant containing nano-calcium-phosphate compounds

BACKGROUND

The present study aimed to evaluate the flexural strength, degree of conversion, and demineralization-prevention ability of an experimental fissure sealant containing nano-calcium-phosphate compounds.

METHODS

An experimental sealant was formulated using silica and nano hydroxyapatite filler particles. The control group consisted of the DENU Seal (n = 10, each group). The flexural bond strength was evaluated by UTM. DC was evaluated by FTIR. To evaluate the demineralization-prevention ability, Cl V cavities in 10 third molar teeth restored with two sealant products, followed by an acid challenge then the Vickers microhardness test was carried out.

RESULTS

The mean flexural strength in the commercial group was higher than the experimental group. However, the mean flexural modulus was not significantly different between the two groups. In the experimental group, DC was significantly higher than the commercial group. Adjacent to the interface, the decrease in microhardness in the experimental group was significantly less than the commercial group. However, on the tooth surface, there were no significant differences between the two groups. In the experimental group, the decrease in microhardness at the interface was less than at the tooth surface, however the situation was opposite in the commercial group.

CONCLUSIONS

Incorporating hydroxyapatite into the sealant structure might prevent demineralization, without adverse effects on flexural modulus and degree of conversion.

Brief Narrative Review on Commercial Dental Sealants-Comparison with Respect to Their Composition and Potential Modifications

The scope of this paper is to compare different dental sealants and flow materials indicated for sealing pits and fissures considering their chemical formula. The narrative review aims to address the following questions: What is the essence of different dental sealants' activity, how does their chemical formula affect their mechanisms of caries prevention, and what makes a dental sealant efficient mean of caries prevention? Another vital issue is whether the sealants that contain fluoride, or any other additions, have potentially increased antimicrobial properties. An electronic search of the PubMed, Cochrane, Web of Science, and Scopus databases was performed. The following keywords were used: (dental sealants) AND (chemical composition). Additionally, information about composition and indications for clinical use provided by manufacturers were utilized. All of the considered materials are indicated for use both in permanent and primary dentition for sealing fissures, pits, and foramina caeca. The selection of suitable material should be made individually and adjusted to conditions of the sealing procedure and patient's needs. Cariostatic mechanisms increasing sealants' effectiveness such as fluoride release are desired in modern dentistry appreciating preventive approach. The review aims are to find crucial elements of sealants' composition which affect their cariostatic mechanisms.

Penetration ability and microhardness of infiltrant resin and two pit and fissure sealants in primary teeth with early enamel lesions

To determine the penetration depth and enamel microhardness (EMH) of an infiltrant resin and two fissure sealants in primary teeth with early enamel lesions. We randomly divided 174 sound teeth into six groups (n = 29): (1) phosphoric acid (PA) + Clinpro, (2) PA + Aegis, (3) Icon, (4) hydrochloric acid (HCl) + Clinpro, (5) HCl + Aegis, and (6) control. Percentage penetration (%PP) was analyzed by confocal laser scanning microscopy (n = 15). EMH was measured (n = 12), and the percentage of EMH recovery (%REMH) was calculated. Twelve samples were examined under a scanning electron microscope (SEM). All data were analyzed with the Kruskal–Wallis and one-way ANOVA tests (p < 0.05). Groups 3 and 4 showed the highest %PP (all, p < 0.05). Icon application led to significantly higher %REMH compared to the others (p < 0.05). Groups 2 and 5 showed the lowest reduction in %REMH after pH-cycling. Application of Icon and Clinpro with HCl pretreatment showed the greatest %PP. pH-cycling led to a decrease in %REMH for all of the materials, although this effect was lower in teeth treated with Aegis.

The clinical effects of laser preparation of tooth surfaces for fissure sealants placement: a systematic review and meta-analysis

BACKGROUND

This systematic review aimed to assess the clinical effects of laser preparation compared to other types of chemical or mechanical preparation of tooth surfaces used in fissure sealant placement.

METHODS

A systematic literature search was conducted up to January 2019, through Pubmed, Scopus, Medline/EMBASE via OVID and the Cochrane library. Only randomized clinical trials were included.

RESULTS

Five studies were included in the systematic review and three were included in the meta-analysis. All the studies used acid-etching as a comparator to lasers. All the included studies were rated as having an overall high risk of bias introduced by performance bias. Three studies assessed the clinical effects of fissure sealants placed by acid or laser etching, one compared acid etching versus laser combined with acid etching and one investigated the influence of lasers on the objective and subjective parameters of stress during sealant application in children. The meta-analysis showed no significant difference between laser preparation and conventional acid-etching preparation at 3- (P = 0.08), 6- (P = 0.49), and 12-month (P = 0.87) follow-ups. One study reported that laser preparation as an adjunct to acid-etching enhanced the retention rate. No significant difference in the incidence of caries was reported. And no significant differences were found in heart rates, oxygen saturation or degree of the patient dental anxiety between acid-etching and laser preparation.

CONCLUSION

The present limited evidence suggests that lasers could be an effective pretreatment method. The retention rate was similar to that of conventional acid etching. However, the included studies had an overall high risk of bias and more rigorously designed research is needed.

Microleakage in Class V Composite Restorations after Desensitizing Surface Treatment with Er:YAG and CO2 Lasers

Aims: Glutaraldehyde, CO₂ and Er:YAG lasers can be used for treatment of dentin hypersensitivity. However, their application may have adverse effects on the clinical service of restorations. This study aimed to assess the microleakage in composite restorations following surface treatment with Glutaraldehyde desensitizer, CO₂ and Er:YAG laser irradiation for treatment of dentin hypersensitivity. Materials and methods: This experimental study was conducted on 60 extracted sound human teeth. Class V cavities were prepared measuring 3×3 mm using a diamond bur. Specimens were randomly divided into 4 groups of 15. Group one:no surface treatment, Group two:applying Glutaraldehyde desensitizer, Groups of three and four were irradiated with CO₂ and Er:YAG lasers, respectively. Surfaces were restored with bonding agent (Single Bond 2, 3M, USA) and Z250 composite (3M, USA). Specimens were thermocycled and immersed in 1% methylene blue solution for 24 hours. Microleakage scores were assessed under a stereomicroscope at ×20 magnification. Data were analyzed using SPSS and the Kruskal Wallis test (P=0.05). Results: There was no significant difference between microleakage of groups in enamel margins (P=0.694). The difference in microleakage at the dentin margin was significant between groups (P=0.018). Conclusions: Application of Glutaraldehyde-desensitizer and CO₂ laser irradiation of surfaces prior to composite restoration do not increase microleakage at the enamel or dentin margins but tooth surface treatment with Er:YAG laser significantly increased the microleakage at the dentin margins.

Morphological changes produced by acid dissolution in Er:YAG laser irradiated dental enamel

Several scientific reports have shown the effects of Er:YAG laser irradiation on enamel morphology. However, there is lack of information regarding the morphological alterations produced by the acid attack on the irradiated surfaces. The aim of this study was to evaluate the morphological changes produced by acid dissolution in Er:YAG laser irradiated dental enamel. Forty-eight enamel samples were divided into four groups (n = 12). GI (control); Groups II, III, and IV were irradiated with Er:YAG at 100 mJ (12.7 J/cm(2) ), 200 mJ (25.5 J/cm(2) ), and 300 mJ (38.2 J/cm(2) ), respectively, at 10 Hz without water irrigation. Enamel morphology was evaluated before-irradiation, after-irradiation, and after-acid dissolution, by scanning electron microscopy (SEM). Sample coating was avoided and SEM analysis was performed in a low-vacuum mode. To facilitate the location of the assessment area, a reference point was marked. Morphological changes produced by acid dissolution of irradiated enamel were observed, specifically on laser-induced undesired effects. These morphological changes were from mild to severe, depending on the presence of after-irradiation undesired effects.