Retention of a filled fissure sealant using reduced etch time. A two-year study in 6 to 8-year-old children

Does etching time affect the in vitro performance of a sealant material?

This in vitro study evaluated the shear bond strength (SBS), failure mode and microleakage of fissure sealing materials in relation to different etching times on aprismatic and prismatic enamel. Ninety-six healthy human third molars were randomly allocated to the following groups: 1) prismatic or aprismatic enamel; 2) etching: 15, 30, 45, 60 s. After 5,000-fold thermocycling SBS, failure mode and microleakage were measured. Statistical evaluation included Mann-Whitney-U-test and linear regression analysis. In the aprismatic enamel group, an increasing etching time resulted in higher SBS. The linear regression model revealed that 60 s of etching time led to a significant increase in SBS. Microleakage was found to be low in all test groups. This study indicated that 60 s of etching time showed to a significantly better SBS. When considering the small differences of SBS, failure modes and microleakage between 30 and 60 s etching time, 30 s acid etching seems to also be justifiable.

Use of a self-etching adhesive on previously etched intact enamel and its effect on sealant microleakage and tag formation

AIM

This study verified the effects of a self-etching adhesive applied on pre-etched fissures (phosphoric acid 35%) on microleakage, penetration ability and tag formation of a fissure sealant.

METHODS

80 extracted sound human molar teeth were randomly divided into four groups and bisected in two equal parts, forming two subgroups, denominated A and B. Groups 1 and 2 were etched with phosphoric acid for 60 and 40s, respectively. Groups 3 and 4 were etched with phosphoric acid (40 and 20s, respectively) and afterwards treated with Xeno III (20s). All the procedures on sealant placement were performed under 90+/-2% relative humidity. The subgroups A and B were submitted to 1000 and 5000 thermal cycles, respectively. The samples were examined by light microscopy and by confocal laser scanning microscopy (CLSM) after sectioning. Microleakage, penetration ability, fissure type, tag formation quality and tag length were measured.

RESULTS

Etching with phosphoric acid for 60s showed statistically significantly lower microleakage when compared to the other groups and significantly better tag formation quality and longer tags compared to 20s H(3)PO(4) plus Xeno III. Fissure type and number of thermal cycles were not significant factors on sealant microleakage. The penetration ability of the sealant in the fissure systems was not influenced by the treatment regimes. Shallow fissures showed a significant better tag formation than deep fissures. No significant difference in the prevalence of fissure types was seen among the groups.

CONCLUSION

Etching fissures with phosphoric acid for 60s showed best results. The additional use of Xeno III did not improve fissure sealing under the conditions of this study.

The effect of different etching times on the retention of fissure sealants in second primary and first permanent molars

This study investigated the effect of different etching times on the retention of fissure sealants in second primary and first permanent molars. Eighty-four children with a total of 144 second primary molars and 264 first molars were included in the study. Etching times of 15, 30, 45 and 60 seconds were used. The fissure sealants were evaluated at 6 and 12 months. The results showed that the overall retention rate of fissure sealants in second primary molars was 73.0% at 6 months and 64.7% at 12 months, whereas in first permanent molars the retention rates were 60.7% at 6 months and 44.1% at 12 months respectively. There was no significant difference in the retention of fissure sealants either on second primary molars or on first permanent molars at a 6- and 12-month follow-up with the different etching times. It was concluded that the different etching times did not appear to affect the retention of fissure sealants on the first permanent molars or second primary molars. It might therefore be prudent to etch the teeth for a much shorter period than conventionally recommended.

Pit and fissure sealant application: updating the technique

Dental sealants have proved an effective way to prevent caries development. The authors discuss available options in sealant materials and placement. They also outline key points in sealant application.

A clinical investigation of the effects of omission of pumice prophylaxis on band and bond failure

One hundred and twelve first molar bands and 614 directly bonded brackets on incisor, canine, and premolar teeth were included in a clinical trail to investigate the importance of omission of pumice prophylaxis at the time of banding and bonding, on their possible subsequent failure. Half of the sample were selected for the non-pumiced test groups using a random number allocation method, the remaining pumiced teeth acting as control groups. Two etch times were used for the direct bonding part of the study, 15 and 60 seconds, with non-pumiced test and pumiced control groups included within both etch-time groups. Results showed no statistical difference in the failure rate of attachments in either test or control groups during the course of treatment. The different etch times had no significant effects in the direct bonding part of the study.

Effect of a fluoridated etchant on the shear bond strength of a composite resin to enamel

The purpose of this study was to evaluate the effect of a fluoridated etching gel on the shear bond strength of a composite resin to enamel. A total of 75 extracted human permanent molars were used. A flat enamel surface was obtained with 600-grit silicon carbide paper and cleaned with a rubber cup and a water slurry of fine flour of pumice. The teeth were randomly distributed into 5 groups of 15 teeth each and etched as follows: group 1: 37% non-fluoridated phosphoric acid gel (Coe) for 60 seconds (control); group 2: 60% phosphoric acid gel with 0.5% NaF (Orthoprep) for 5 seconds; group 3: Orthoprep for 15 seconds; group 4: Orthoprep for 30 seconds; group 5: Orthoprep for 60 seconds. After etching, rinsing and drying, an unfilled resin (Coe Bond) was thinly applied with a brush and cured for 30 seconds. A nylon ring was placed over the area and filled with a light-cured composite resin (Occlusin). The teeth were thermocyled (100x), mounted in plastic cups and plaster, and sheared with a knife-edged blade in an Instron machine running at a crosshead speed of 1 mm/min. The results in MPa were as follows: group 1: 14.49 +/- 4.43; group 2: 10.81 +/- 3.70; group 3: 13.51 +/- 3.21; group 4: 14.79 +/- 3.76; group 5: 15.47 +/- 4.07. An analysis of variance showed that the results in groups 1, 4 and 5 were not significantly different but that the bond strengths in groups 2 and 3 were significantly lower. Fracture within the enamel occurred in 8 specimens in group 1, 5 in group 2, 6 in group 3, 8 in group 4, and 13 in group 5. In the fluoridated etchant groups the number of specimens showing enamel fracture increased as the application time of the etchant increased.

A clinical trial comparing the failure rates of directly bonded brackets using etch times of 15 or 60 seconds

A clinical trial was conducted to compare bond failure when 15-second or 60-second acid etch times were used for the direct bonding of metal edgewise brackets. Bonds totaling 1174 were studied over a period of 6 to 13 months. Analysis of failure rate, bond survival time, and cement remaining after failure showed no statistical difference between the 15-second and 60-second etch groups. There were statistical differences in bond failures relating to the position of the tooth in the arch (p less than 0.001) and to the type of bracket (p less than 0.001).

Retention of pit and fissure sealant on the primary molars of 3- and 4-year-old children after 1 year

An investigation of pit and fissure sealant retention in 1,871 children in the Head Start program was conducted in Tennessee in September 1985 to determine the retention of the sealant after application to the occlusal surfaces of primary molars of 3- and 4-year-old children. The investigation shows pit and fissure sealants are retained on primary molars at a rate comparable to that expected on permanent molars.

The effects of differing etch times on the etch pattern on enamel of unerupted and erupted human teeth examined using the scanning electron microscope

The etch pattern produced on enamel from unerupted and erupted human teeth with varying periods of acid etching using 37 per cent phosphoric acid was examined using a scanning electron microscope. For erupted enamel etch scores were fairly consistent above 10 seconds etching, for unerupted enamel etch scores matched those for erupted enamel for etch times above 30 seconds. The etch type was more consistent on unerupted enamel.