Spectrophotometric Analysis of Antibiotic-Induced Tooth Discolouration: An In Vitro Study

This study evaluated tooth discolouration potential of triple antibiotic paste (TAP) containing either minocycline or cefuroxime, Ledermix and Odontopaste using spectrophotometric analysis.

Sixty extracted human maxillary central incisors were standardised to 17 mm in length. After canal preparation with ProTaper Next to F5, specimens were randomly allocated to 6 groups (n=10). (Group A-F) Ledermix, TAP with minocycline, TAP with cefuroxime, Odontopaste, positive control (blood) and negative control (saline). Medicaments were placed via apical access to preserve crown integrity. Colour measurements were recorded using a spectrophotometer (Vita Easyshade Advance) at baseline, 3 days, 1 week, 2 weeks and 12 weeks. Specimens were stored at 37°C in darkness between the measurements. Colour changes (ΔE) were calculated using CIE Lab* formula. Data were analysed using two-way analysis of variance (ANOVA) with Bonferroni post-hoc tests (α=0.05).

All experimental groups showed significant discolouration at 12 weeks (P < .05), exceeding the clinically perceptible threshold (ΔE > 3.7). Triple antibiotic paste with minocycline demonstrated the highest discolouration (ΔE=22.86 ± 9.99), followed by Ledermix (ΔE=19.11 ± 11.26) and TAP with cefuroxime (ΔE=18.72 ± 8.37), with no significant difference between the latter 2 (P > .05). Odontopaste showed the least discolouration (ΔE=10.06 ± 5.10). All medicaments exhibited progressive, time-dependent discolouration (P < .05).

All tested antibiotic-containing medicaments caused clinically perceptible tooth discolouration. Triple antibiotic paste containing cefuroxime showed numerically lower discolouration than minocycline containing TAP, although both exceeded clinically acceptable thresholds and were not significantly different from Ledermix (P > .05). Odontopaste exhibited the lowest discolouration among the tested medicaments (ΔE=10.06), yet still exceeded the clinically acceptable limit.