Surface Sealant Effect on the Color Stability of a Composite Resin Following Ultraviolet Light Artificial Aging

OBJECTIVE

To examine how exposure to accelerated artificial aging (AAA) stimuli (ultraviolet [UV] light) affects the color stability of a composite resin following surface sealant (SS) application.

METHODS AND MATERIALS

A total of 30 cylindrical composite resin (Esthet-X) discs were prepared using Teflon-coated rings. The treatment groups, defined by different SS (Seal-N-Sine, PermaSeal, OptiGuard, Biscover LV, and DuraFinish) use, were divided into five groups of six discs each. The discs were subjected to baseline color measurements followed by measurements after surface sealant application (specular included component [SCI] and specular excluded component [SCE]) using a spectrophotometer. Three measurements (SCI and SCE) were performed for a total of 18 readings (test surface) per specimen group. All specimens were then exposed to a UV light source for a total of 382 hours. Color readings of the specimens were again recorded for each group. Quantitative color measurements were executed using Commission Internationale de l'Eclairage L*a*b* calculations.

RESULTS

Baseline color measurements of the composite resin discs, following the AAA exposure protocol, revealed no significant differences. A comparison of the composite resin discs before and after SS application (without UV light exposure) showed statistically significant differences using both SCI and SCE measurement criteria. Although significant differences were encountered between the ΔL*, Δa*, Δb*, and ΔE parameters, all specimens (groups) were within the clinically acceptable range (1.0<ΔE≤ 3.3). Again, statistically significant differences were noted (ΔL*, Δa*, Δb*, and ΔE parameters) for all specimen groups receiving SS application, utilizing both SCI and SCE measurements, following exposure to UV light. All groups were within the clinically acceptable range (1.0<ΔE≤ 3.3), except the Durafinish group. The Durafinish SS group experienced significantly greater (p<0.001) overall color change (SCI and SCE) following UV light exposure. An intergroup comparison following UV exposure revealed that the Permaseal, OptiGuard, and Seal-n-Shine SS groups displayed the least amount of color change statistically but not necessarily always perceptibly significant, while the Durafinish group exhibited the greatest color change statistically and perceptibly.

CONCLUSIONS

The color stability of a composite resin, including the addition of most SSs, was not affected perceptibly by UV light exposure.

Who actually does orthopaedic operating?

Recent correspondence in the British Medical Journal suggested that up to 80% of orthopaedic trauma surgery is carried out by unsupervised trainees. We examined our own experience by gathering theatre computer system data over a six month period and case note verification. Unsupervised trainees carried out 48% of the trauma surgery, but only 13% of the elective surgery. Case sheet review demonstrated that the computer system over-attributed operating to the senior surgeon, and under-recorded the presence of unscrubbed consultants. Supervision of trainees is important for both training and service provision, and needs to be tailored to the needs of individual trainees, but we were disappointed with our results. Theatre computer records may not be accurate enough to allow assessment of the level of supervision.