Effect of phytic acid and ethylenediaminetetraacetic acid on penetration depth of bioceramic and resin sealers

This study assessed influence of 1% phytic acid and 17% ethylenediaminetetraacetic acid (EDTA) on the dentinal tubules penetration of EndoSequence BC bioceramic-based and AH Plus resin-based sealers using confocal laser scanning microscopy (CLSM). Forty single-rooted mandibular premolars were divided randomly into four groups (n = 10). Group 1 received final irrigation with 1% phytic acid solution and canals sealed by AH Plus sealer, Group 2: 1% phytic acid solution and EndoSequence BC sealer, Group 3: 17% EDTA solution and AH Plus sealer and Group 4: 17% EDTA solution and EndoSequence BC sealer. Specimens were horizontally sectioned 2, 4 and 6 mm from the apex. Average maximum depth of sealer penetration was examined using CLSM. Group three showed the deepest sealer penetration at all three levels which was significantly higher than all other groups (P ˂ 0.05). Deep sealer penetration is achievable with AH Plus and EDTA. Phytic acid groups have moderate tubular penetration ability.

Ion release and recharge from a fissure sealant containing amorphous calcium phosphate

To assess- the release of calcium and phosphate ions from a fissure sealant containing amorphous calcium phosphate (ACP), and to determine the re-release capacity of these ions when charged with a solution containing casein phosphopeptide-amorphous calcium phosphate (CPP-ACP). Nine blocks of ACP resin-based sealant were prepared and immersed in three solutions at different pH (4.0, 5.5, 7.0), and calcium and phosphate ion release was measured with ion chromatography at 1, 3, 5, 7, 14, 21 and 28 days after immersion. Sixty days after immersion, each block was charged with CPP-ACP solution in three 7-day cycles to investigate the re-release of these ions, which was measured on days 1, 3, and 7. No difference was observed in initial calcium ion release at pH 4.0 and pH 5.5. At both values, ion release was significantly higher than at pH 7.0 (p<0.001). Initial phosphate release was significantly different among the three pH values (p<0.001). After re-charging the specimens, calcium ion re-release was greater than phosphate ion release. Initial ion release from ACP resin-based sealant was greatest at the lowest pH. Ion release decreased with time. As the number of recharge cycles increased, ion re-release also improved. Phosphate ion re-release required more recharge cycles than calcium ion re-release.

Anti-biofilm activity of a novel pit and fissure self-adhesive sealant modified with metallic monomers

Dental plaque is a biofilm composed of a complex oral microbial community. The accumulation of plaque in the pit and fissures of dental elements often leads to the development of tooth decay (dental caries). Here, potent anti-biofilm materials were developed by incorporating zinc methacrylates or di-n-butyl-dimethacrylate-tin into the light-curable sealant and their physical, mechanical, and biological properties were evaluated. The data revealed that 5% di-n-butyl-dimethacrylate-tin (SnM 5%) incorporated sealant showed strong anti-biofilm efficacy against various single-species (Streptococcus mutans or Streptococcus oralis or Candida albicans) and S. mutans-C. albicans cross-kingdom dual-species biofilms without either impairing the mechanical properties of the sealant or causing cytotoxicities against mouse fibroblasts. The findings indicate that the incorporation of SnM 5% in the experimental pit and fissure self-adhesive sealant may have the potential to be part of current chemotherapeutic strategies to prevent the formation of cariogenic oral biofilms that cause dental caries.

Microcavitated (ICDAS 3) carious lesion arrest with resin or glass ionomer sealants in first permanent molars: A randomized controlled trial

OBJECTIVES

Although there is some consensus that carious lesions in early stages (non-cavitated) could be treated using sealants, neither the type of materials nor their use in lesions with localized enamel breakdown (microcavitated) has been reported To compare the efficacy of resin or glass ionomer (GI) sealants in arresting microcavitated carious lesions (ICDAS 3) in first permanent molars.

MATERIALS AND METHODS

A double-blinded randomized controlled clinical trial was conducted in 41 healthy 6 to 11-year-old children. At the baseline examination, each subject had at least one carious lesion classified as ICDAS 3 on the first permanent molar. One hundred fifty-one lesions were randomized into: Group 1: resin sealants (76 lesions) and Group 2: GI sealant (75 lesions). Carious lesion progression was assessed clinically and radiographically. Progression and retention failure were the outcomes used for group comparisons at p-value<0.05.

RESULTS

After a two-year follow-up, only one lesion progressed to ICDAS 5, without statistically significant differences between the groups (χ²(1) = 0.90, p = 0.53). Radiographically, 100 lesions (98%) were arrested and 2 (2%) showed radiographic progression, without differences between groups (χ²(1) = 0.93, p = 0.93). At 2 years, complete retention was observed in 77% of the resin-based and in 83% of the GI sealants, without statistical differences between type of sealant (χ²(1) = 0.71, p = 0.48). The multilevel mixed model demonstrated that location and type of sealant did not affect retention rates (χ²(1) = 24,98, p < 0.001).

CONCLUSION

Sealing ICDAS 3 carious lesions in permanent molars appears to be effective in arresting lesions after a two-year follow-up. Clinicaltrials.gov: RCTICDAS3/2015.

CLINICAL SIGNIFICANCE

Minimally invasive approaches for carious lesion management have been promoted. Using sealants for the treatment of microcavitated lesions (ICDAS 3) appears predictable in the routine practice, without predilection for resin or glass ionomer materials. In addition to preserving tooth structure, this strategy reduces chair-time, dental fear and costs, and increases coverage to dental care.

Dental Sealants Part 4: Bisphenol A: What dentists should know

Bisphenol A (BPA) is a synthetic chemical resin used worldwide to produce plastic products. It is also a component of the bisphenol A diglycidylether methacrylate (Bis-GMA), which is a monomer found in dental resin-based materials (including resin-based dental sealants, RBSs). The controversy about its possible toxicity begins around the early '30s. Even if the amount of BPA released by dental sealants is well below the limit proposed by the U.S. Environmental Protection Agency and the European Food Safety Authority, we can reduce the risk of exposure, particularly for children, following precautionary measures.

Effect of Cured Versus Uncured Adhesive Inclusion on the Microtensile Bond Strength of Sealants

PURPOSE

To determine the impact of light curing of bonding agents on the microtensile bond strength (MTBS) of sealants on extracted teeth.

METHODS

Flat enamel surfaces were created on 54 extracted, sound human molars by sequential grinding. Three different sealants- Clinpro (3M ESPE), Ultraseal XT Hydro (Ultradent), and Fluorshield VLC (Dentsply)- were placed after acid etching without a bonding agent (control) or with three different bonding agents - Adper Single Bond Plus (3M ESPE), Peak Universal Bond (Ultradent), and Prime&Bond Elect (Dentsply)- each in both light-cured and uncured form. The teeth were sectioned into bar specimens and the MTBS of each specimen was measured. The bond strength data were analyzed using two-way analysis of variance and Tukey's test (P=0.05).

RESULTS

There was no significant difference between the MTBS of sealants in the thermocycled and non-thermocycled groups. The uncured adhesive had the lowest bond strength in each group, except for Clinpro after thermocycling. Teeth with uncured adhesive exhibited significantly lower bond strength in the Ultraseal (no thermocycling) and Fluroshield (with thermocycling) groups (P=0.02 and P=0.001, respectively).

CONCLUSIONS

Adding bonding agents without curing before sealant placement weakened the microtensile bond strength. There was no significant difference in MTBS between the thermocycled and nonthermocycled groups.

Long-term release of fluoride from fissure sealants-In vitro study

The intensity of the cariostatic activity of fluoride ions can be attributed to their multidirectional influence on the caries process. They are an irreplaceable factor that helps sustain mineral balance of dental tissues, simultaneously demonstrating antibacterial properties. As a consequence, many manufacturers of fissure sealants include fluoride ions in their products. The aim of this in vitro study was to determine long-term fluoride release from four fissure sealants (Conseal F, Fissurit FX, Delton Fs+, Admira Seal). During a 14-week-long observation, all the materials showed a relatively constant level of F- release; however, it is crucial to mention that within the first 48h, the most significant increase in fluoride release was found for Fissurit and Delton sealants. Based on the overall assessment, the highest total amount of the released fluoride ions was observed for Delton, and the lowest level was reported for Admira Seal.

Ion release and in vitro enamel fluoride uptake associated with pit and fissure sealants containing microencapsulated remineralizing agents

PURPOSE

To determine if pit-and-fissure sealants with microencapsulated remineralizing agents with sustained release of fluoride, calcium and phosphate ions could promote enamel fluoride uptake by demineralized tooth structure.

METHODS

Sealants that contained 5 w/w% microcapsules with aqueous solutions of 5M Ca(NO3)2 or 0.8M NaF or 6.0M K2HPO4 or a mixture of all three were prepared. Ion release profiles were measured as a function of time. Enamel fluoride uptake by demineralized tooth structure was determined.

RESULTS

Sustained release of fluoride, calcium and phosphate ions from a sealant was demonstrated. Fluoride uptake by demineralized enamel was significantly increased compared to a control sealant manufactured without microcapsules (P< 0.01). Bovine enamel that contained 2.2±2.1 µg F/g of enamel prior to exposure to a sealant without microcapsules had 2.3±0.5 after 90 days. Enamel exposed to sealant with 5w/% NaF microcapsules went from 3.5±3.5 µg F/g of enamel prior to exposure to 148±76 after 90 days. Enamel exposed to sealant with 2 w/w% NaF, 2 w/w% Ca(NO3)2 and 1 w/w% K2HPO4 microcapsules went from 1.7±0.7 µg F/g of enamel prior to exposure to 190±137 after 90 days.

CLINICAL SIGNIFICANCE

Sealants with encapsulated remineralizing agents were capable of releasing biologically available fluoride, calcium, and phosphate ions. Incorporation of these microcapsules in pit and fissure sealants is a promising method for remineralization determined by enamel fluoride uptake measurements.

The Effect of Fluoride Varnish on Enamel Shear Bond Strength of Pit and Fissure Sealants

PURPOSE

The purpose of this study was to determine the effects of fluoride varnish on the enamel shear bond strength of pit and fissure sealants.

METHODS

Ninety-six teeth were divided into three duplicated test groups: sealant (S)/sealant thermocycle (ST) received Clinpro Sealant only; varnish sealant (VS)/varnish sealant thermocycle (VST) received five percent sodium fluoride (NaF) varnish plus sealant (VPS); and VPS/VPS thermocycle (VPST) received NaF, polish with Clinpro Prophy Paste, plus sealant. One set of each group (ST, VST, VPST) was thermocycled to represent aging, and one set (S, VS, PVS) was not. The shear bond strengths for the thermocycled groups and nonthermocycled groups were determined, and two-way analysis of variance tested the effects of thermocycling and varnish.

RESULTS

Thermocycling did not have a significant effect on the peak stresses of the groups (P=0.0552), so sets were combined. The peak stress for S/ST was significantly higher than for VS/VST (P<0.0001). The peak stress for VPS/VPST was significantly higher than for VS/VST (P<0.0001). The peak stress for S/ST was significantly higher than VPS/VPST (P=0.025).

CONCLUSION

Fluoride varnish applied immediately before pit and fissure sealant placement negatively affected the shear bond strength of the sealant. Mechanically cleaning a fluoride varnish-coated tooth with prophy paste did not provide pit and fissure sealant enamel shear bond strengths comparable to those of untreated enamel.

Penetration of Filled and Unfilled Resin Sealants on Different Enamel Substrates

PURPOSE

To evaluate the penetration ratio of filled and unfilled resin-based sealants on different enamel substrates and pit and fissure morphologies.

METHODS

Forty-eight occlusal enamel blocks obtained from impacted human third molars were randomly divided (n equals eight) according to enamel substrates (sound; caries-like lesion; caries-like lesion plus topical fluoride application) and sealant material (FluroShield; Helioseal Clear Chroma). Sealants were applied on the enamel surface. The specimens were stored in 100 percent humidity for 24 hours at 37 degrees Celsius, sectioned in a buccal-lingual direction (at approximately 50 μm), and examined to determine the sealant penetration ratio (b x 100/a; a equals total fissure length and b equals sealant penetration length) and pit and fissure morphology (V-, U-, or Y-shaped). Statistical analysis was performed using Friedman and Kruskal-Wallis tests (P<0.05).

RESULTS

Enamel substrate and sealant material did not affect the sealant penetration ratio, with no interactions between these factors. Moreover, the morphology significantly affected the sealant penetration, with the "Y"-shaped fissures presenting the lowest sealant penetration ratio compared to "U-"shaped (P=0.0001) and "V-" shaped fissures (P=0.0018).

CONCLUSIONS

Pit and fissure morphology was a critical factor on sealant's penetration capacity; however, enamel substrate and sealant type did not affect sealant's penetration ratio.

Synthetic phenolic antioxidants, including butylated hydroxytoluene (BHT), in resin-based dental sealants

Resin-based dental sealants (also referred to as pit-and-fissure sealants) have been studied for their contribution to bisphenol A (BPA) exposure in children. Nevertheless, little attention has been paid to the occurrence of other potentially toxic chemicals in dental sealants. In this study, the occurrence of six synthetic phenolic antioxidants (SPAs), including 2,6-di-tert-butyl-4-hydroxytoluene (BHT), 2,6-di-tert-butyl-4-(hydroxyethyl)phenol (BHT-OH), 3,5-di-tert-butyl-4-hydroxy-benzaldehyde (BHT-CHO), 2,6-di-tert-butylcyclohexa-2,5-diene-1,4-dione (BHT-Q), 3,5-di-tert-butyl-4-hydroxybenzoic acid (BHT-COOH) and 2-tert-butyl-4-methoxyphenol (BHA), was examined in 63 dental sealant products purchased from the U.S. market. BHT was found in all dental sealants at median and maximum concentrations of 56.8 and 1020µg/g, respectively. The metabolites of BHT and BHA were detected in 39-67% of samples, at concentration ranges of <LOQ to 242µg/g. BHT is likely used in sealants to inhibit oxidative reactions, remove free radicals, and inhibit potential polymerization, which would eventually prolong the shelf-life of the products. The estimated daily intake (EDI) of BHT, following sealant placement, based on a worst-case scenario (application on eight teeth at 8mg each tooth), was 930 and 6510ng/kg bw/d for adults and children, respectively. The EDI of BHT from dental sealants was several orders of magnitude lower than the current acceptable daily intake (ADI) proposed by the European Food Safety Authority (EFSA).

Pit and Fissure Sealant Retention Following Air Abrasion Preparation with Bioactive Glass and Aluminum Oxide Particles

PURPOSE

Alumina air abrasion is an alternative for acid-etch technique for tooth preparation before placement of a fissure sealant. The aim of this study was to compare the retention of sealants placed subsequent to air abrasion with alumina and bioactive glass (BAG) particles.

METHODS

Sixty-two 6-12 year old children were included in this study. Using a halfmouth design, the fissures were prepared using air abrasion with alumina particles on randomly assigned permanent mandibular or/and maxillary first molars on one side of the mouth (Group 1) and air abrasion with BAG on the contralateral side of the mouth (Group 2). Sealants were applied on 180 teeth, and were scored as missing, partially retained, and completely retained after three, six, nine and 12 months. Data were analyzed using Friedman and Wilcoxon tests (α=0.05).

RESULTS

Sealant retention rates in the alumina group were higher than those in the BAG group at all time periods (P<0.001).

CONCLUSIONS

Sealant retention after air abrasion with alumina particles was higher than BAG over 12 months.

Shear Bond Strength and Microleakage of a New Self-etching/Self-adhesive Pit and Fissure Sealant

PURPOSE

To evaluate shear bond strength and microleakage of a new self-etching/self-adhesive fissure sealant on prismless enamel compared with conventional fissure sealing.

MATERIALS AND METHODS

A total of 90 extracted third molars were assigned to 3 main groups: group 1: self-etching/self-adhesive sealant, without acid etching; group 2: self-etching/self-adhesive sealant, with prior acid etching; group 3: conventional fissure sealing (control group). After specimen preparation, each group was divided into 3 subgroups according to storage time (1-day water storage, 3-month water storage, and 1-day water storage followed by 5000x thermocycling). The shear bond strength was determined with a universal testing machine, according to ISO standard 29022. Afterwards, the failure mode was analyzed. An additional 24 third molars were used for microleakage assessment. The fissure pattern was sealed in strict accordance with the manufacturers' instructions. After thermocycling, the dye penetration was examined. Data were analyzed using the Mann-Whitney U-Test at a significance level of 0.05.

RESULTS

The shear bond strength of the self-etching/self-adhesive fissure sealant without prior acid etching was significantly lower (4.3 MPa) than that of the self-etching/self-adhesive fissure sealant with prior acid etching (17.1 MPa) and the conventional fissure sealing (19.1 MPa). Microleakage was significantly lower in the control group (1.1%) and in the group with the self-etching/self-adhesive sealant with prior acid etching (0.8%) compared to the group that used the self-etching/self-adhesive material alone (49.4%).

CONCLUSION

The self-etching/self-adhesive fissure sealant can be recommended for clinical use when enamel is etched with phosphoric acid. The self-etching/self-adhesive sealant without prior acid etching showed significantly inferior results.

The impact of Er:YAG laser enamel conditioning on the microleakage of a new hydrophilic sealant--UltraSeal XT hydro

UltraSeal XT® hydro™ is a new hydrophilic, light-cured, methacrylate-based pit and fissure sealant which has been developed by Ultradent Products, USA. The sealant is highly filled with a 53 wt.% mixture of inorganic particles which confer both thixotropy and radiopacity. The principal purpose of this study was to investigate the microleakage of UltraSeal XT® hydro™ as a function of different enamel etching techniques. The occlusal surfaces of sound, extracted human molars were either acid etched, Er:YAG laser irradiated or successively laser irradiated and acid etched. UltraSeal XT® hydro™ was applied to each group of teeth (n = 10) which were subjected to a thermocycling process consisting of 2500 cycles between 5 and 50 °C with a dwell time of 30 s. Microleakage assessments were then carried out using 0.5 % fuchsin dye and optical microscopy. The microleakage score data were analysed using the Kruskal-Wallis, Mann–Whitney U test with Bonferroni adjustment. No significant differences in microleakage were noted between the individually acid etched and laser-irradiated groups (p > 0.05); however, teeth treated with a combination of laser irradiation and acid etching demonstrated significantly lower microleakage scores (p < 0.001). Electron microscopy with energy-dispersive X-ray analysis revealed that the mineral filler component of UltraSeal XT® hydro™ essentially comprises micrometre-sized particles of inorganic silicon-, aluminium- and barium-bearing phases. Laser etching increases the roughness of the enamel surface which causes a concentrated zoning of the filler particles at the enamel-sealant interface.

Evaluation of shear bond strength, penetration ability, microleakage and remineralisation capacity of glass ionomer-based fissure sealants

AIM

The aim of this study was to evaluate the bond strength, penetration ability, microleakage, and remineralisation capacity of glass ionomer-based fissure sealant materials.

MATERIALS AND METHODS

In this study, three glass ionomer-based fissure sealants were evaluated (Fuji Triage, Fuji VII EP, and GCP Glass Seal). A dye-penetration test was performed to evaluate microleakage under a stereomicroscope. The materials were applied to occlusal tooth surfaces, and bucco-lingual sections (1 mm width) were assessed to evaluate the penetration ability. Shear bond strength of tested materials was assessed using a universal testing machine. Finally, the remineralisation capacities of the materials were evaluated with EDS.

RESULTS

The Fuji Triage exhibited the lowest microleakage and unfilled area proportion (p<0.05). The highest shear bond strength was calculated with Fuji VII EP (p<0.05). The fluoride content for all treatment groups was significantly different when remineralisation values were compared to demineralisation (p<0.05).

CONCLUSION

Both the Fuji Triage and Fuji VII EP yielded compatible and satisfactory results and all fissure sealants used in this study are sufficient as anti-caries agents.

Evaluation of Different Fissure Sealant Materials and Flowable Composites Used as Pit-and-fissure Sealants: A 24-Month Clinical Trial

PURPOSE

The effectiveness of resin-based pit-and-fissure sealants mainly depends on their retention and integrity over time. The purpose of this study was to evaluate retention rates of two different pit-and-fissure sealants compared with a flowable composite and a self-adhesive flowable composite over a 24 month period.

METHODS

A split-mouth study design was used for all four permanent first molars of each patient. They were subjected to different kinds of sealants--either flowable composites or with fissure sealants. The flowable composites used were: flowable composite with an adhesive system (Tetric EvoFlow); and a self-adhesive flowable composite (Vertise Flow). The fissure sealants used were: a highly filled pit-and-fissure sealant (Fissurit FX); and a highly filled nano-hybrid pit-and-fissure sealant (Grandio Seal). Evaluation of the sealants was carried out at three-, six-, 12-, 18-, and 24-month follow-up visits.

RESULTS

The complete retention rates were 95.7 percent for Tetric EvoFlow, 80.6 percent for Fissurit FX, 73.1 percent for Grandio Seal, and 62.9 percent for Vertise Flow. The retention rate of Tetric EvoFlow was significantly higher among all materials tested (P<0.05).

CONCLUSION

The flowable composite used with an adhesive system was found to be superior to other sealing materials.

Buffering or non-buffering; an action of pit-and-fissure sealants

OBJECTIVES

The aim of this study was to evaluate the buffering capacity of glass-ionomer material in vitro. The null hypothesis tested was that there is no effect of cured glass-ionomer pit-and-fissure sealant (PFS) pastes on the environmental acidity as well as the tooth substrate.

METHOD

For each material, a cured PFS disk and a section of human enamel were simultaneously soaked in lactic acid solution in a conical tube, and the pH of the solution was measured daily for one week. Subsequently, the total amount of calcium leached out in solution was also measured with ICP-AES.

RESULTS

The results showed that the acidity of the solutions changed over time. Significant differences of calcium ion concentration in solution were observed as a result of decalcification. As the PFS products tested did not include calcium, the concentration of calcium ion released indicated acidic erosion of the tooth enamel.

CONCLUSIONS

The glass-ionomer countered the acid of the solution rapidly and preserved the structure of human tooth enamel.

Retention of Moisture-tolerant and Conventional Resin-based Sealant in Six- to Nine-year-old Children

PURPOSE

The purpose of this study was to evaluate and compare the retention rates and development of caries in permanent molars in children sealed with moisture-tolerant, resin-based (Embrace WetBond), and conventional resin-based (Helioseal) sealant over a period of one year.

METHODS

This was a double blind, split-mouth, randomized controlled trial among six- to nine-year-olds. Sixty-eight permanent mandibular first molars in 34 children were randomly assigned to be sealed with Embrace WetBond or Helioseal sealant.

RESULTS

The final sample was 32 children with 64 teeth. At 12 months, 23 of 32 (72 percent) sealants were completely retained in Embrace WetBond, whereas only 16 of 32 (50 percent) were retained in the Helioseal group. There was a statistically significant difference in retention rates of Embrace WetBond and Helioseal sealants at 12 months (P<.05). At 12 months follow-up, only two teeth developed caries in Embrace WetBond; in the Helioseal group, five teeth developed caries (two initial and three enamel caries).

CONCLUSIONS

Embrace WetBond was superior to Helioseal sealant, as Embrace exhibited higher retention and lower caries scores. Embrace WetBond can be preferred over conventional resin-based sealants for community and outreach sealant programs where use of rubber dam for moisture control is difficult to practice.

Can Increasing the Manufacturer's Recommended Shortest Curing Time of High-intensity Light-emitting Diodes Adequately Cure Sealants?

PURPOSE

To investigate sealant depth of cure after increasing the curing times of high-intensity light-emitting diode units (LEDs).

METHODS

Three sealants (opaque-unfilled, opaque-filled, and clear-filled) were light cured in a covered-slot mold with: (a) three LEDs (VALO, SmartLite, Fusion) for six to 15 seconds; and (b) a quartz-tungsten halogen (QTH) light for 40 seconds as a control (N=10). Twenty-four hours after light curing, microhardness was measured at the sealant surface and through the depth at 0.5 mm increments. Results were analyzed via analysis of variance followed by the Student-Newman-Keuls test (significance level 0.05).

RESULTS

The opaque-filled and clear-filled sealants cured with VALO for six or nine seconds had hardness values that were statistically equivalent to or better than the QTH to a depth of 1.5 mm. Using Fusion for 10 seconds (exposure limit) did not adequately cure the three sealants beyond one mm. SmartLite at 15 seconds (maximum exposure period without overheating) did not adequately cure the sealants beyond 0.5 mm.

CONCLUSIONS

Among the tested high-intensity LEDs, only VALO at double or triple the manufacturers' shortest curing time (six or nine seconds) provided adequate curing of opaque-filled and clear-filled sealants at 1.5 mm depth compared to the 40-second QTH light.

Report on the clinical technique of thermo-curing glass-ionomer sealant

Controversy exists regarding the general safety of resin sealants and in particular their use in children, due to the possible leaching of non-polymerized monomers including bisphenol A. A thermally cured high-viscosity glass-ionomer cement (GIC) is suggested as a first-choice sealant material. An innovative approach of thermo-curing the GIC during placement is presented. The step-by-step clinical procedure and rationale for the biomimetic thermo-cured glass-ionomer fissure sealant are introduced and described. A thermally cured GIC sealant may provide long-term caries protection to fissures and pits without the need to maintain and reseal. GICs are both biocompatible and biomimetic resulting in formation of fluorapatite, the ultimate protection against dental caries.

Resin-based pit-and-fissure sealants: microleakage reduction and infiltration enhancement using a bonding agent

PURPOSE

To evaluate the marginal microleakage and the infiltration ability of pit-and-fissure sealants by applying the conventional sealing technique in comparison to using an additional bonding agent.

MATERIALS AND METHODS

Extracted non-carious permanent molars (n = 60) were first stored in sterile saline solution and then assigned to one of two groups: group C (control) was sealed (Helioseal F) by using the conventional technique, while in group BA (bonding agent), a bonding agent (OptiBond FL) was additionally applied prior to sealing. The teeth were thermocycled (1000 cycles, 5°C to 55°C, dwell time 30 s), then varnished and immersed in 5% methylene blue solution for 24 h. After embedding and sectioning each tooth into 6-12 slices, the presence of microleakage, unfilled areas, and air bubbles trapped in the sealant were assessed with a stereomicroscope.

RESULTS

A higher proportion of microleakage was found under sealants applied without the additional use of the bonding agent. A statistically significant difference in microleakage was noted between the groups (p = 0.045). Regarding the presence of unfilled areas, a statistically significant difference between the groups was observed (p < 0.001), especially since no unfilled areas were found at all in the samples of the group using the bonding agent. Regarding the amount of air bubbles trapped in the sealant, no statistically significant difference was observed between the two groups (p = 0.829).

CONCLUSION

Under these in vitro conditions, sealant procedures using an additional bonding agent applied beforehand significantly improved fissure infiltration and microleakage prevention significantly.

Bond strength of a sealant to enamel after a cariogenic challenge using three bonding protocols: an in vitro study

PURPOSE

The purpose of this study was to evaluate in vitro the tensile bond strength of a resin-based pit and fissure sealant to enamel after a cariogenic challenge using three bonding protocols.

METHODS

The demineralized tooth specimens were assigned to three groups of equal size: Group 1 (37 percent phosphoric acid gel), Group 2 (total-etch adhesive system), and Group 3 (one-step self-etch adhesive system). After the surface treatment, a resin-based sealant was applied and cured. The specimens were thermocycled and tensile bond strength was measured using a universal testing machine by an investigator who was blinded to the group distribution.

RESULTS

The mean tensile bond strength was highest with the total-etch adhesive system, which was statistically significant (P<.001). A post hoc test revealed a significant difference between Groups 1 and 2 (P<.001) and Groups 2 and 3 (P<.001), but none between Groups 1 and 3 (P=.44).

CONCLUSION

The total-etch bonding system resulted in significantly higher tensile bond strength with incipient enamel caries.

Rationale for caries inhibition of debonded glass ionomer sealants: an in vitro study

PURPOSE

This study's purpose was to test the hypothesis that, after glass ionomer (GI) sealant debonding, remaining GI in the deepest parts of fissures and/or the inhibition of enamel demineralization after artificial caries challenge imparts the residual cariostatic property observed in clinical studies.

METHODS

Fuji IX GI sealant was placed on one tooth from 14 matched pairs of noncarious extracted human permanent molars and premolars; the other tooth was the control. Sealed teeth underwent thermocycling (4,000 cycles), and the sealant was manually debonded. The amount of remaining sealant in the fissures was determined using a stereomicroscope. All teeth were placed in lactic acid gel (pH 5.0) at 37 degrees Celsius for three weeks to simulate caries formation. The extent of demineralization was determined using the serial micro-hardness method on the cross-sectioned specimens at 0.5 mm from the depth of the central fissure.

RESULTS

All teeth had GI retained in the fissures at a microscopic level. Enamel demineralization adjacent to the remaining GI was not significantly different from the control (t test; P=.88).

CONCLUSIONS

The residual cariostatic property of glass ionomer sealant is most likely due to a physical barrier of remaining GI in the fissures rather than a chemical effect on demineralization inhibition.

The effect of antibacterial agents on fissure sealant microleakage: a 6-month in vitro study

PURPOSE

To evaluate microleakage from an antibacterial adhesive and bonding agent added to the ssure sealant on intact enamel.

MATERIALS AND METHODS

One hundred twenty sound third mandibular molars were randomly divided into 6 groups of 20 teeth each. Occlusal pits and ssures were sealed with un lled sealant material (Clinpro, 3M) after pretreatment with 1. phosphoric acid etching (control); 2. acid etching + Adper Single Bond 2 (SB, 3M); 3. chlorhexidine digluconate (CHX, Ultradent) + acid etching; 4. CHX + acid etching + SB; 5. acid etching + Clear l Protect Bond (CPB, Kuraray) 6. CPB alone. After 6-month water storage and thermocycling, the specimens were placed in 0.5% fuschin, sectioned and evaluated under a digital microscope. The data were compared between groups with Kruskal-Wallis and Mann-Whitney tests.

RESULTS

Differences between groups were statistically signi cant at P < 0.05. Acid etching alone and with SB showed the lowest microleakage, followed by acid etching + CPB. Chlorhexidine with and without bonding agent showed the greatest microleakage.

CONCLUSION

Conventional acid etching alone or with a one-bottle adhesive were the two most effective methods of reducing microleakage from ssures. Acid etching together with a self-etching adhesive showed better results than self-etching alone. Appling CHX increased microleakage in sealed teeth.

Adhesive interface and bond strength of endodontic sealers to root canal dentine after immersion in phosphate-buffered saline

This study evaluated the bond strength (BS) and the adhesive interface of four endodontic sealers to root canal dentine, before, and after immersion in phosphate buffered saline (PBS) to simulate an in vivo environment. Eighty roots were instrumented using ProTaper rotatory files, under irrigation with 17% EDTA and 1% NaOCl. Posteriorly were divided into four groups (n = 20) according to the sealer used: Endofill, AH Plus, Sealapex, and MTA Fillapex. Each group was divided into two subgroups (n = 10) and stored at 37°C immersed in water for 7 days and in PBS for 60 days. From each subgroup, 1 mm thick sections were obtained. One section of each region (coronal, middle, and apical) was submitted to the push-out test and failures were observed. Twelve sections of each subgroup (four from each region) were evaluated under SEM. Three-way ANOVA evaluation for BS showed significant differences between groups and regions (P < 0.0001), but not between subgroups (P > 0.05). AH Plus had significantly higher BS than the others sealers, regardless of the analyzed subgroup (Tukey's test, P < 0.5). The most common failures were adhesive to dentine and cohesive of the sealer. The SEM evaluation (Kruskal-Wallis, Mann-Whitney) showed homogeneous adhesive interface formed and sealer tags in all groups with significant statistical differences with AH Plus, regardless of PBS immersion. AH Plus was superior to the other sealers for both BS and quality of interface formation. Immersion in PBS did not interfere on BS or adhesive interface of the sealers tested.

Dental sealants and restorations and urinary bisphenol A concentrations in children in the 2003-2004 National Health and Nutrition Examination Survey

BACKGROUND

Resin-based dental sealants and composites contain bisphenol A-glycidyl methacrylate, a bisphenol A (BPA) derivative. The authors hypothesized that a greater number of sealants or restorations would be associated with higher urinary BPA concentrations.

METHODS

The authors examined urinary BPA measurements (in nanograms per milliliter) and oral examination data for 1,001 children aged 6 to 19 years from data sets of the 2003-2004 National Health and Nutrition Examination Survey (NHANES). They categorized children according to number of occlusal sealants and number of restorations, with four categories in each of the two groups. They estimated associations by using unadjusted and adjusted tobit regression models.

RESULTS

The lowest quartile of BPA concentrations ranged from 0.3 ng/mL to 1.9 ng/mL, whereas the highest quartile ranged from 7.3 ng/mL to 149 ng/mL. In adjusted analysis, children with seven to 16 sealants had geometric mean BPA concentrations 25 percent higher than those of children with no sealants (95 percent confidence interval [CI], -14 percent to 82 percent; P = .23). In adjusted analysis, children with seven to 42 restorations had geometric mean BPA concentrations 20 percent higher than those of children with no restorations (95 percent CI, -6 percent to 53 percent; P = .13). Neither of these adjusted estimates was statistically significant.

CONCLUSIONS

Though the findings were in the direction hypothesized, the authors did not observe a statistically significant association between a greater number of sealants or restorations and higher urinary BPA concentrations. Additional studies are needed to determine the extent of oral and systemic exposure to BPA from resin-based dental restorative materials over time.

PRACTICAL IMPLICATIONS

Dentists should follow this issue carefully as it develops and as the body of evidence grows. There is insufficient evidence to change practice at this time.

Resistance against bacterial leakage of four luting agents used for cementation of complete cast crowns

PURPOSE

To assess the sealing properties of four luting materials used for cementation of full cast crowns.

METHODS

40 human premolars were prepared with a chamfer finish line. Stone dies were fabricated and copings were waxed, invested and cast in gold. Ten samples (n = 10) were randomly assigned to four groups. In two groups, resin modified glass-ionomer cements were used, ACTIVA BioACTIVE-CEMENT/BASE/LINER and FujiCem2; the third group received the self-adhesive resin cement Embrace WetBond, while the fourth group served as control with a zinc phosphate cement. After cementation, excess cement was removed followed by bench-set for 10 minutes. All samples were stored in water at 37 degrees C and subjected to thermal cycling (x2000 between 5 and 55 degrees C). Subsequently the occlusal surface was reduced exposing the dentin. After sterilization the specimens were subjected to bacterial microleakage with E. faecalis in a dual chamber apparatus for a period of 60 days. Bacterial leakage was checked daily. Data were analyzed using the Kaplan-Meyer survival test. Significant pairwise differences were analyzed using the Log Rank test and the Fishers' exact test at P < 0.05.

RESULTS

ACTIVA BioACTIVE-CEMENT/BASE/LINER, FujiCem2 and Embrace WetBond showed the lowest microleakage scores and differed statistically significantly (P < 0.05) from zinc phosphate cement.

Near-infrared imaging of demineralization under sealants

Previous studies have shown that near-infrared (NIR) reflectance and transillumination imaging can be used to acquire high contrast images of early caries lesions and composite restorative materials. The aim of the study was to determine the optimum NIR wavelengths for imaging demineralized areas under dental sealants. Fifteen natural human premolars and molars with occlusal lesions were used in this in vitro study. Images before and after application of sealants were acquired using NIR reflectance and NIR transillumination at wavelengths of 1300, 1460, and 1500 to 1700 nm. Images were also acquired using polarization sensitive optical coherence tomography (OCT) for comparison. The highest contrast for NIR reflectance was at 1460 nm and 1500 to 1700 nm. These NIR wavelengths are coincident with higher water absorption. The clear Delton sealant investigated was not visible in either copolarization or cross-polarization OCT images. The wavelength region between 1500 and 1700 nm yielded the highest contrast of lesions under sealants for NIR reflectance measurements.

In vitro comparison of the bond strength to the enamel of conventional and self-etching dental fissure sealants

AIM

Dental caries in pits and fissures of molars is still very common in young people, despite a gradual reduction in their incidence and prevalence. Prevention with the aid of dental fissure sealants can help to reduce the onset of decay. In vitro tests were conducted to compare the bond strength to enamel of self-etching sealants versus those applied using the conventional procedure.

METHODS

The lingual surface of 40 extracted, caries-free, mandibular third molars was milled to make them flat. The prepared teeth were randomly divided into two groups of 20 teeth each: those in Group A were treated with Clinpro (3M ESPE, St. Paul, MN, USA); those in Group B with Quick Seal (BJM Laboratories Ltd, Or-Yehuda, Israel). Cylinders of sealant were attached to the enamel of the flat surfaces of the samples using a polymerisation process treating the surfaces involved according to the type of material. All samples underwent load testing by means of a universal test machine.

RESULTS

The results of the load testing, measured in MPa, were analysed using the Student's t-test for independent samples and the differences proved significant, indicating that the traditionally- applied sealant (mean strength 21.06 MPa) assured a significantly stronger bond (p <.05) than the self-etching sealant (mean strength 10.43 MPa) under our experimental conditions. CONCLUSION Conventional sealants generally provide a considerably higher bond strength than self-etching sealants.

A comparative evaluation of shear bond strength of different pits and fissure sealants: an in vitro study

AIM

The aim of this study was to determine and compare the shear bond strength of three different pits and fssure sealants to enamel namely, Delton, Clinpro and Z350 Filtek fowable composite.

MATERIALS AND METHODS

Ninety permanent molars were divided into three groups of 30 each. Their proximal surfaces were prepared and stored in 37°C ± 5°C normal saline for 24 hours. Sealant buttons were prepared. The specimens were tested in a shear mode (Lloyds LR100K) at a crosshead speed of 0.5 mm/min. The mean and standard deviations were subjected to an analysis of variance.

RESULTS

The mean shear bond strength of samples of Delton was 10.33 MPa; Clinpro was 8.51 MPa and Z350 Filtek fowable was 12.17 MPa. The mean strength of Delton was signifcantly higher as compared to Clinpro whereas the mean strength of Z350 Filtek was signifcantly higher as compared to Delton and Clinpro (Student t-test, p < 0.001).

CONCLUSION

Z350 Filtek fowable composite had maximum shear bond strength than Delton FS sealant followed by Clinpro sealant. Clinical signifcance: In this study, we compare the bond strength of three pits and fssure sealant, Clinpro yielded lower bond strength than Delton. This outcome can be described due to the presence of fllers in Delton, since these particles increase the resistance of the material to abrasion and also increase the mechanical resistance of the material.

Microleakage of two fluoride-releasing sealants when applied following saliva contamination

The purpose of this in vitro study was to evaluate microleakage of two fluoride-releasing sealants in saliva contaminated and non-contaminated conditions. Twenty-four human third molars were randomly assigned to two groups: saliva contaminated and saliva non-contaminated teeth. In the contaminated group, the teeth were contaminated with 0.02 ml artificial saliva for 20 seconds and blowed dry afterward. Each group was divided into two subgroups: Group A, a fluoride-releasing resin sealant marketed as Clinpro and Group B, a glass-ionomer sealant marketed as Fuji VII. After sealant application, all the teeth were thermocycled for 2,000 cycles and coated with nail varnish 1.0 mm from the sealed areas. The teeth were stained with 2% methylene blue dye for 24 hours and sectioned in the bucco-lingual direction. Dye penetration (microleakage) was examined with a 25x polarized light microscope and measured by a computerized-calculated method. Data were compared with the Mann-Whitney U test at significance level of p<0.05. A comparison of the two types of sealant revealed microleakage of the glass-ionomer sealant was present but there was no significant difference between the saliva contaminated and saliva non-contaminated teeth. Microleakage of the fluoride-releasing resin sealant was present and was greater among the saliva-contaminated teeth than the saliva non-contaminated teeth. The glass-ionomer sealant had significantly greater microleakage than the fluoride-relasing resin-based sealant in both the saliva-contaminated and saliva non-contaminated teeth.

Biochemical and microbiological characteristics of in situ biofilm formed on materials containing fluoride or amorphous calcium phosphate

PURPOSE

To evaluate the biochemical and microbiological characteristics of in situ biofilm formed on materials that release fluoride (F-) or calcium (Ca++) and phosphate (Pi).

METHODS

This study comprised an in situ and in vitro experiment, utilizing three materials [Auralay XF and Fuji IX GP, containing fluoride, and Aegis containing amorphous calcium phosphate (ACP)] and bovine dental enamel slabs. For the in situ: 10 volunteers wore palatal devices, each containing four material specimens or enamel slabs that were treated with 20% sucrose solution. The biofilm had pH measurements on Day 7 and the composition was analyzed on Day 8 by assessing the following: F-, Ca++, Pi and insoluble extracellular polysaccharides (EPS) concentrations, and then identification of the microbiota. For the in vitro: materials/enamel were subjected to a 7-day pH-cycling regimen to determine F, Ca++ and Pi release.

RESULTS

The biofilm formed on F(-)-releasing materials was richer in F, Ca++ and Pi and had lower mutans streptococci counts than enamel biofilm. The biofilm on the ACP-containing material exhibited similar Ca++ and Pi concentrations to biofilm on F(-)-releasing materials. The materials showed buffering action compared with enamel. Biochemical and microbiological characteristics showed a less cariogenic biofilm on materials containing fluoride or amorphous calcium phosphate.

Effectiveness of a self-etching adhesive on sealant retention in primary teeth

PURPOSE

The purpose of this study was to conduct a clinical evaluation of fissure sealant retention in primary teeth using self-etching adhesive Adper Prompt L-Pop or a conventional phosphoric acid-etching technique.

METHODS

A total of 90 primary second molars indicated for sealants were selected from 45 healthy 4- to 6-year-olds. A randomized, split-mouth design was applied using bilateral primary second molars. Sealant retention was evaluated, using the Color Coverage Caries sealant evaluation system, and blindly checked by the same examiner at six and 12 months.

RESULTS

There was no statistically significant difference in the retention of sealant using self-etching adhesives vs the conventional acid-etching technique. Statistically significant lower retention rates were found with both techniques after evaluating at 12 months vs six months.

CONCLUSIONS

Replacing phosphoric acid-etching with self-etching adhesive Adper Prompt L-Pop does not compromise sealant retention in primary teeth after a 1-year period.

Biology and cytotoxicity of dental materials: an in vitro study

OBJECTIVE

The purpose of the experiment was to determine the degree of biocompatibility of a sealer (RO, laboratory made product) dental material in terms of cytotoxicity and animal tests.

MATERIALS AND METHODS

In the present study, the biological compatibility of eight experimental composite materials was examined by in vitro methods. The bio-composites used for the cytotoxicity test were placed into direct contact with normal human fibroblasts in a cell-culture dish. After fibroblast bioassay was performed, a duplicate sample of biomaterial was placed in each well, and then the fibroblasts were incubated for 48 hours at 37°C and 5% carbon dioxide. Local reactions after the implantation of the material regarding preclinical evaluation have been carried out within the Biobase Laboratory of the "Iuliu Hatieganu" University of Medicine and Pharmacy, Cluj-Napoca, Romania. The biocompatibility was studied using the tolerance test by the subcutaneous and intramuscular implantation of the cured specimens.

RESULTS

The sealant C3 scored the highest value to the cell viability. The results of the present study showed that different dental materials had different effects on cells. The resin monomer TEGDMA, present in the sealer's composition, increased the amount of intracellular reactive oxygen species. Resin-based composites are cytotoxic before polymerization and immediately thereafter, whereas already set specimens cause almost no reaction. The test of tolerance showed that the composite materials do not contain any toxic, irritant substances or destructive ones for the living cells or tissues.

CONCLUSIONS

The tests with experimental composite materials revealed that they are not cytotoxic for the living cells, in all versions of the materials used. All the samples of composite materials have maintained their integrity during the experiment, allowing the testing together with the embedded cells, which proved good viability, so they are suitable for dentistry use.

Microbial microleakage assessment of a new hydrophilic fissure sealant: a laboratory study

PURPOSE

The purpose of this study was to compare microbial leakage of a new hydrophilic sealant with that of a conventional hydrophobic resin-based sealant.

METHODS

One hundred extracted, caries-free, human maxillary premolars were randomly divided into five groups. Those in Groups 1, 2, and 3 had dry, wet, and artificial saliva-contaminated occlusal surfaces, respectively, and were sealed with a hydrophilic sealant, while those in Groups 4 and 5 had dry and wet occlusal surfaces, respectively, and were sealed with a hydrophobic sealant. A newly designed microbial penetration method utilizing Streptococcus mutans as an indicator was tested for leakage assessment. Data were analyzed using SPSS 15.0 software, and the significance level was set at α=0.05.

RESULTS

The log rank test indicated a statistically significant difference in leakage rates among the five groups. Mantel-Cox log-rank test findings showed that Group 3 had the highest leakage rate, with Groups 2 and 4 having the lowest. There was no statistically significant difference in leakage rate between Groups 2 and 4.

CONCLUSIONS

With respect to the limitations of an in vitro study, our findings suggest that hydrophilic sealants are an acceptable alternative to hydrophobic sealants.

Formulation and characterization of antibacterial fluoride-releasing sealants

PURPOSE

The purpose of this study was to formulate and characterize experimental antibacterial fluoride-releasing sealants and compare them with commercial sealants for fluoride release, recharge, adhesion, and microleakage.

METHODS

Two experimental sealants (Exp-1, Exp-2) containing a synthesized antibacterial fluoride-releasing monomer and fluoride-releasing filler were formulated. Exp-2 also contained NovaMin nanoparticles. Commercial sealants Clinpro (CL) FluroShield (FS), and SeLECT Defense (E34) were also included. Fluoride release from disk samples in deionized water was measured daily using an ion-selective electrode for 14 days, and after recharging with Neutra-Foam (2.0% sodium fluoride), fluoride was measured for 5 days. Microtensile bonding strengths (MTBS) to enamel were tested after 24-hour storage in water at 37°C or thermocycling 5-55°C for 1,000 cycles. A microleakage test was conducted on extracted teeth using a dye-penetration method. The data were analyzed using analysis of variance with the Tukey's honestly significant difference test and Kruskal-Wallis test.

RESULTS

Exp-1 and Exp-2 had significantly higher fluoride release and recharge capabilities than CL and FL (P<.05). All tested sealants had similar MTBS before and after thermocycling. Exp-2 and Exp-1 had significantly lower microleakage scores (P<.05) than other groups.

CONCLUSION

The experimental sealants had higher fluoride release and recharge capabilities and similar or better retention than commercial sealants.

What every dentist should know about bisphenol A

Bisphenol A (BPA) is a common industrial chemical that has been associated with a variety of biological disorders. From the unborn to the elderly, BPA affects every demographic of the population; however, its potential long-term effects on prenatal and prepubescent development have led to concern about its use in the field of pediatrics. Because BPA is omnipresent in modern society, the use of BPA derivatives (such as Bis-GMA and Bis-DMA) in dental materials in general, and acrylic resins in particular, will be increasingly examined as research continues to implicate BPA in a number of biological disorders.

Salivary bisphenol-A levels due to dental sealant/resin: a case-control study in Korean children

Dental sealants and composite filling materials containing bisphenol-A (BPA) derivatives are increasingly used in children. The aim of this study was to evaluate the association between salivary BPA and the number of tooth surfaces filled with dental sealant, and to determine a cutoff BPA level. Salivary BPA concentration and the number of tooth surfaces filled with dental sealant/resin were determined in 124 age and gender matched children: 62 controls had no dental sealant/resin on their tooth surfaces and 62 cases had more than 4 tooth surfaces with dental sealant/resin. Analysis of covariance (ANCOVA) and conditional logistic regression were performed after controlling for age, gender, salivary flow rate, salivary buffer capacity, frequency of snacking, and frequency of tooth brushing. Salivary BPA levels were 0.002 to 8.305 µg/L. The BPA level of control (0.40 µg/L) was significantly lower than that of case (0.92 µg/L) after controlling for confounders (P = 0.026). Although the 90th BPA percentile had an adjusted OR of 4.58 (95% CI 1.04-20.26, P = 0.045), the significance disappeared in the conditional logistic model. There may be a relationship between salivary BPA level and dental sealant/resin.

Comparison of retention rates of fissure sealants using two flowable restorative materials and a conventional resin sealant: two-year follow-up

OBJECTIVE

The purpose of this clinical study was to compare the retention rates of two flowable restorative systems (Admira Flow and Grandio Flow) with that of a conventional resin-based sealant (Fissurit F).

MATERIALS AND METHODS

The study was planned as a clinical trial with a split-mouth design. A total of 122 sealants (38 Admira Flow, 41 Grandio Flow, 43 Fissurit F) were randomly applied to completely erupted permanent molars in 35 patients aged 9-20 years and followed up for 24 months. Data were analyzed using Pearson's χ(2) and multiple comparison tests.

RESULTS

At the end of the follow-up period, Fissurit F had higher retention rates (81.0%) than both Admira Flow (60.5%) and Grandio Flow (57.1%), with p < 0.05. However, there was no significant difference in caries development among groups (p > 0.05).

CONCLUSION

The two flowable composite resin materials used as fissure sealant were less retentive than the conventional resin sealant.

Influence of the light curing tip distance and material opacity on selected physical properties of a pit and fissure sealant

PURPOSE

The purpose of this study was to evaluate the influence of the light curing tip distance and material opacity on hardness (KHN), degree of conversion (DC), and crosslink density (CLD) of a resin-based fissure sealant (Fluroshield).

METHODS

One-millimeter-thick white opaque and clear sealant specimens, photoactivated at 1-, 2-, and 3-mm distances, were fabricated (8 groups, N=5). KHN and DC were evaluated 24 hours after polymerization. Specimens were subjected to a new KHN reading after 24-hour immersion in absolute ethanol to indirectly assess the CLD.

RESULTS

Samples of clear sealant cured at longer distances presented lower KHN, although there were not differences between opacities at all distances. The mean DC of the opaque white material, however, was lower than that of the clear one at higher distances. There were no differences among CLD for all experimental conditions analyzed.

CONCLUSIONS

KHN of the clear sealant was affected by increased distances. The clear sealant showed higher DC at increased distances, although CLD was not influenced by the factors under study. Since physical properties of sealing materials are directly related to their clinical efficacy, the clear sealant tested may present a better clinical performance than the opaque one.

Effectiveness of a five-step method for teaching clinical skills to students in a dental college in India

This study conducted at the PDM Dental College and Research Institute, Haryana, India, had the purpose of developing a teaching method based upon a five-step method for teaching clinical skills to students proposed by the American College of Surgeons. This five-step teaching method was used to place fissure sealants as an initial procedure by dental students in clinics. The sealant retention was used as an objective evaluation of the skill learnt by the students. The sealant retention was 92 percent at six- and twelve-month evaluations and 90 percent at the eighteen-month evaluation. These results indicate that simple methods can be devised for teaching clinical skills and achieve high success rates in clinical procedures requiring multiple steps.

Microleakage of self-etching sealant on noncontaminated and saliva-contaminated enamel

PURPOSE

The purpose of this study was to compare the microleakage of a self-etching sealant with a traditional phosphoric acid-etched sealant under noncontaminated and saliva-contaminated conditions.

METHODS

Fifty-two sound extracted human molars were randomly divided into 4 groups (N=13). Teeth in Groups 1 and 2 were cleaned with pumice, etched with phosphoric acid, rinsed, coated with a drying agent, placed with sealants (UltraSeal XT Plus), and light cured. Teeth in Groups 3 and 4 were cleaned with a proprietary flour pumice and rinsed prior to being sealed with a self-etching sealant (Enamel Loc). Teeth in Groups 2 and 4 were contaminated with saliva and thoroughly air-dried prior to the sealant placement. All teeth were subjected to a thermocycling process, stained with silver nitrate, and sectioned, and images of the sealant on the occlusal surface were recorded. Microleakage distance was measured in millimeters and subjected to a 2-way analysis of variance.

RESULTS

Significantly larger microleakage distances were found for the self-etching sealant vs the traditional sealant (P<.001). Saliva contamination did not significantly affect the microleakage distance (P<.17).

CONCLUSIONS

Under the conditions used in this in vitro study, the self-etching sealant, regardless of contamination condition, had extensive microleakage distances vs. little microleakage in the traditional phosphoric acid-etched sealant.

Microleakage of silorane- and methacrylate-based class V composite restorations

The marginal integrity of class V restorations in a silorane- and a group of methacrylate-based composite resins with varying viscosities was tested in the present study. Different adhesives (OptiBond FL, KerrHawe; AdheSE One, Vivadent; or Silorane System Adhesive, 3M ESPE) were applied to 168 standardized class V cavities. The cavities (n = 12) were filled with a wide range of different viscous composite resins: Filtek Silorane, 3M ESPE; els and els flow, Saremco; Tetric EvoCeram and Tetric EvoFlow, Vivadent; Grandio, Voco; and Ultraseal XT Plus, Ultradent. Microleakage of the restoration was assessed by dye penetration (silver staining) on multiple sections with and without thermocycling and mechanical loading (TCML: 5,000 × 5-55°C; 30 s/cycle; 500,000 × 72.5 N, 1.6 Hz). Data were statistically analyzed with the Mann-Whitney U test and the Error Rates Method (ERM). The silorane-based composite resin yielded the lowest dye penetration after TCML. Microleakage of methacrylate-based composite restorations, in general (ERM), was statistically significantly influenced by the adhesive system, Moreover, dye penetration at enamel margins was significantly lower than dye penetration at dentin margins. The chemical basis of composite resins and adjacent tooth substance seems to strongly influence marginal sealing of class V restorations for methacrylate-based materials. Moreover, the steps of dental adhesives used affected marginal integrity. The silorane-based composite resin evaluated in the present study exhibits the best marginal seal. The three-step adhesive yielded better marginal sealing than the one-step adhesive for methacrylate-based class V composite restorations.

Effect of light curing methods on microleakage and microhardness of different resin sealants

PURPOSE

This study's purpose was to evaluate the effect of light curing methods on the microleakage and microhardness of sealants.

METHODS

The Elipar Free Light 2 light emitting diode (LED) with 10- and 20-second curing times, and the Elipar 2500 halogen light with a 20-second curing time were compared. Four different sealants were used: (1) Delton Clear; (2) Delton Opaque; (3) UltraSeal XT Clear; and (4) UltraSeal XT Opaque. Specimens were fabricated in a silicone mold (2-mm thick) and cured. Knoop hardness was measured at the bottom and top surfaces. For the microleakage evaluation, 120 human molars were divided into 12 groups and sealed with the sealants and curing methods, as stated previously. The teeth were thermocycled and immersed in 2% methylene blue for 24 hours. Each tooth was sectioned and examined for dye penetration.

RESULTS

There were no statistically significant differences in the microleakage of sealants polymerized by either the halogen or LED curing methods. The microhardness of sealants varied according to the type of material and curing method.

CONCLUSIONS

A 10-second polymerization time with light emitting diodes was not sufficient to cure the 2-mm-thick opaque or high filler loaded sealants. Decreasing the curing time, however, had no effect on the microleakage of the sealants.

Advances in dental materials

The use of materials to rehabilitate tooth structures is constantly changing. Over the past decade, newer material processing techniques and technologies have significantly improved the dependability and predictability of dental material for clinicians. The greatest obstacle, however, is in choosing the right combination for continued success. Finding predictable approaches for successful restorative procedures has been the goal of clinical and material scientists. This article provides a broad perspective on the advances made in various classes of dental restorative materials in terms of their functionality with respect to pit and fissure sealants, glass ionomers, and dental composites.

Wear of dental sealing materials using the replication technique

AIM

The aim of the present study was an in vivo evaluation of the wear of different sealing materials using the replication technique.

MATERIALS AND METHODS

Four different sealing materials were randomly applied on 2 out of 4 caries-free permanent first molars of each patient. Impressions were taken at T0: before the sealing material was applied; T1: right after the application; T2: 6 months after the application, and T3: 1 year after the application. The impressions were then processed for scanning electron microscopy analysis of the wear of the examined materials. Statistical analysis was used to evaluate differences among and within the 4 groups.

RESULTS

At T2, the average ratio of residual material in all the groups was 62.37% ± 1.21%, while at T3 it was 49.63% ± 1.11%. At both T2 and T3 there were no statistically significant differences among the 4 groups examined (p=0.76 and p=0.50 respectively). Comparison within the same group at T2 and T3 showed that statistically significant differences were only detected in group D (p=0.015).

CONCLUSION

Sealing materials do not undergo a complete loss after 1 year of application, thus indicating that they are suitable for caries prevention.