Abstract
After selective carious tissue removal, residual carious lesions remain radiographically detectable. Radiopaque tagging resolves the resulting diagnostic uncertainty but impedes bond strengths of adhesives to tagged dentin. We developed a protocol mitigating these detrimental effects. A 30%/50%/70% SnCl2 solution was dissolved in distilled water or a 30%/50%/90% ethanol solution (E30/60/90) and applied to artificially induced dentin lesions. Tagging effects were radiographically evaluated using transversal wavelength-independent microradiography (n = 6/group). Groups with sufficient tagging effects at the lowest SnCl2 concentrations were used to evaluate how tagging affected the microtensile bond strength of a universal adhesive (Scotchbond Universal) to sound and carious dentin (n = 10/group). Two different protocols for removing tagging material were tested: 15 s phosphoric acid etching and 5 s rotating brush application. Scanning/backscattered electron microscopy (SEM/BSE) and energy-dispersive X-ray spectroscopy (EDS) were used to assess surfaces after tagging and removal. The most promising removal protocol was revalidated microradiographically. Tagging significantly increased the radiopacity, with consistent effects for 30% SnCl2 dissolved in water or E30. Microscopically, tagged surfaces showed a thick carpet of SnCl2, and tagging reduced bond strengths significantly on carious dentin but not on sound dentin (p < 0.01). On carious dentin, removal of tagging material using acid etching and rotating brush was microscopically confirmed. Acid etching also mitigated any bond strength reduction (median: 21.3 MPa; interquartile range: 10.8 MPa) compared with nontagged dentin (median: 17.4 MPa; interquartile range: 20.6 MPa). This was not the case for brushing (median: 13.2 MPa; interquartile range: 13.9 MPa). Acid etching minimally reduced the radiographic tagging effect (p = 0.055). Phosphoric acid etching reduces the detrimental bond-strength effects of tagging without significantly decreasing radiographic tagging effects when using a universal adhesive.
Highlights
For deeper carious lesions, selective carious tissue removal is recommended, which aims to avoid pulp exposure and pulpal complications and preserve pulp vitality and health [1,2]
Radiopaque tagging of carious dentin prior to the restoration placement has been suggested to overcome this uncertainty: tagged carious dentin was no longer detectable on radiographs, while tagging effects were shown to decrease in case the described inactivation of the lesion was not achieved [8]
This study aimed to evaluate different strategies for improving bond strengths of a universal adhesive after tagging carious dentin
Summary
Selective carious tissue removal is recommended, which aims to avoid pulp exposure and pulpal complications and preserve pulp vitality and health [1,2]. Carious tissue is intentionally left close to the pulp during the excavation process, while in the peripheral areas of the cavity, excavation is performed until firm or hard dentin remains, ensuring restoration longevity and a tight seal of the cavity [2]. There is a growing body of evidence supporting selective removal [5], while admittedly the majority of studies have been conducted in the primary and not the permanent dentition [6,7]. One drawback of this strategy, though, is sealed dentin remaining detectable as radiolucency beneath the restoration [8]. Radiopaque tagging of carious dentin prior to the restoration placement has been suggested to overcome this uncertainty: tagged carious dentin was no longer detectable on radiographs, while tagging effects were shown to decrease in case the described inactivation of the lesion was not achieved [8]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
