PubMed · 11495570
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J Nicholls. Remember when?. https://pubmed.ncbi.nlm.nih.gov/11495570/
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Since most cavity preparations show not only areas of exposed enamel and superficial dentin but also of deep dentinal areas, it would be desirable to use a dental adhesive which can obtain equally good bond strength to these hard tissues. The objective of this study was to measure the bond strength of self-etching adhesives to enamel and superficial and deep dentin. Human molars were ground to expose a surface of enamel or superficial (2.0-2.5 mm distance to pulp) or deep dentin (0.5-1.0 mm), embedded in acrylic resin and assigned to three groups (total n=90). The adhesives tested were: Clearfil SE Bond (SE), Prompt L-Pop (LP), and Etch&Prime 3.0 (EP). After application of the adhesives, an inverted, truncated cone of composite (Pertac II, ESPE) was cured. After storage, specimens were debonded in tension at a cross-head speed of 0.5 mm/min. The median tensile bond strength values to enamel were SE 29.1 MPa, LP 22.4 MPa, and EP 21.5 MPa. The median bond strengths for superficial dentin were SE 27.3 MPa, LP 8.4 MPa, and EP 3.2 MPa. The median bond strengths for deep dentin were SE 20.2 MPa, LP 5.7 MPa, and EP 1.3 MPa. The adhesives tested bonded effectively to enamel, but only SE achieved promising bond strengths to superficial and deep dentin.
OBJECTIVES: The aim of the study was to investigate the relationship between etch patterns produced on surface enamel by phosphoric acid and the corresponding bond strengths achieved. MATERIALS AND METHODS: Twenty-eight patients had the buccal surface of their teeth etched and replicated for examination under the scanning electron microscope, at the commencement of orthodontic treatment. Histometry was employed to assess the nature and quality of etch patterns using a four-point scale. Twenty of each tooth type (total of 240), were collected and A Company pre-adjusted orthodontic brackets, bonded using Transbond light-cured orthodontic adhesive according to the manufacturer's instructions and 24-hour bond strength testing was undertaken. The Adhesive Remnant Index (ARI) was recorded for the tooth and bracket surface for all specimens. RESULTS: The type of etch was not significantly affected by the side (left or right) of the mouth assessed (p = 0.532). Overall, there was no significant difference between etch types for upper and lower teeth (p = 0.218); however, there were significant differences between specific teeth in the upper and lower arch. The greatest amount of Type A etch (well-defined etched enamel prisms) was found on the lower incisors, yet in all cases this 'ideal' etch was found to occupy less than 5% of the etched buccal surface enamel. The greatest area of etched enamel surface was occupied by Type C (etched but enamel prisms not evident). The mean bond strength values varied significantly between different tooth types, with the lowest bond strength found on the upper first molar(6.5MPa) and the highest on the lower first molar (13.1 MPa). CONCLUSIONS: An ideal etch pattern is not essential in order to produce a strong bond.
To make a direct biomechanical comparison between the sandblasted and acid-etched surface (SLA) and the machined and acid-etched surface (MA), a well-established animal model for implant removal torque testing was employed, using a split-mouth experimental design. All implants had an identical cylindrical solid-screw shape with the standard ITI thread configuration, without any macroscopic retentive structures. After 4, 8, and 12 weeks of bone healing, removal torque testing was performed to evaluate the interfacial shear strength of each surface type. Results showed that the SLA surface was more powerful in enhancing the interfacial shear strength of implants in comparison with the MA surface. Removal torque values of the SLA-surfaced implants were about 30% higher than those of the MA-surfaced implants (p = 0.002) except at 4 weeks, when the difference was at the threshold of statistical significance (p = 0.0519). The mean removal torque values for the SLA implants were 1.5074 Nm at 4 weeks, 1.8022 Nm at 8 weeks, and 1.7130 Nm at 12 weeks; and correspondingly, 1.1924 Nm, 1.3092 Nm, and 1.3226 Nm for the MA implants. It can be concluded that the SLA surface achieves a better bone anchorage than the MA surface, and that sandblasting before acid etching has a beneficial effect on the interfacial shear strength. As regards the bone-implant interfacial stiffness calculated from the torque-rotation curve, the SLA implants showed an overall more than 5% higher stiffness compared with the MA implants, although the difference did not reach the statistical significance level.