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Abstract:

Laser induced fluorescence (LIF) have been used to set the end-point of caries-excavation. It is speculated, however, that surface characteristics of residual dentin, such as staining and thickness in relation to the underlying pulp tissue, can influence LIF readings. Objectives: to compare mineral density and degree of staining in residual dentin after caries-excavation to LIF measurements taken with a DIAGNOdent pen (Kavo, Biberach, Germany). Methods: Forty-six teeth presenting occlusal caries were excavated using either a conventional low-speed tungsten-carbide bur (H1SE, Komet-Brasseler, Lemgo, Germany), a ceramic bur (K1SM CeraBur, Komet-Brasseler), a sono-abrasion tungsten-carbide tip (Cariex system TC tip 72, Kavo), two experimental enzymatic solutions (SFC-V or SFC-VIII, 3M-ESPE, Seefeld, Germany), or the Carisolv solution (MediTeam, Goteborg, Sweden). All teeth were scanned by a micro-CT device (Skyscan 1172, Skyscan, Kontich, Belgium), and the mineral density at the deepest part of the cavity was calculated. The degree of staining in residual dentin was calculated in L*a*b* color space units in stereomicroscopic images of the excavated teeth after calibration with a standard gray path (Gretag Macbeth Mini Color Checker, X-Rite, Grand Rapids, USA), where lower L* values indicate a high degree of staining. Results: Mean mineral density values in residual dentin were higher in SFC-V compared to CeraBurs (Tukey-Kramer, p<0.05). Tooth elements with no residual caries (n=22) presented lower L* values (41.19±17.63) than elements with residual caries (58.5±14.18; n=24) (t-Test, p<0.01), indicating that darker staining was associated with absence of residual caries. Residual dentin staining resulted in higher LIF readings (r=-0.86, p<0.01) and higher mineral density values (r=-0.62, p<0.01). Residual dentin thickness in relation to the pulp tissue was not correlated to LIF (r=0.02, p>0.05). Conclusions: Determination of a caries removal end-point by means of LIF readings in stained dentin lesions can lead to over-excavation.