Comparative Study of the Gross Interpretation of Phototesting and Objective Measurement with Using a Spectrophotometer for Patients with Psoriasis and Vitiligo Treated with Narrow-band UVB

BACKGROUND:Determination of the minimal erythema dose (MED) is important for developing a phototherapy protocol and to diagnosis photosensitivity disorders. But obtaining a precise and reproducible MED is quite difficult because a phototest for erythema is based on subjective assessment. OBJECTIVE: The objective of our study was to compare the gross interpretation of a phototest and the objective measurement using a spectrophotometer for determining the parameters of cutaneous narrow-band UVB (NBUVB) therapy. METHODS: A total of 14 psoriasis and 10 vitiligo patients who receiving NBUVB phototherapy with skin types III and IV were selected for this study. To perform phototesting, ten sites on the skin of the back were vertically exposed to a series of 10 NBUVB doses among 14 doses between 340 and 1,400 mJ/cm2. We interpreted the gross findings of erythema and measured the L*a*b* values with using a spectrophotometer at each phototest spot and at the control skin. Also, we evaluate the relationship between the gross presentation and the spectrophotometric analysis by delta E for the assessment of the minimal perceptible erythema (MPE) and MED. RESULTS: For all the subjects, the MEDs were measured in the 490~1,000 mJ/cm2 range. The average of the colorimetric values for the control skin were L*: 64.8, a*: 7.9 and b*: 19.8. Among them, the L* value and MED value were shown to be inversely correlated, and as the L* value was decreased, the MED was increased. For the MPE, the delta E, which was the color difference of the normal skin and the phototest area, was within the range of 1.5~3.0 in 17 of the 21 patients, and 4 patients were within the range of 1.0~1.5. For the MED, among the 21 patients, the delta E of 17 patients was within the range of 3.0~6.0, and 4 patients were within the range of 6.0~12.0. CONCLUSION: A spectrophotometer enables UV erythema to be assessed objectively and quantitatively, and this can compensate for the disadvantages of subjective gross interpretation when determining the MED. Delta E is a good novel and objective indicator for determining the MPE and MED. So, a spectrophotometer is a very useful instrument for developing a phototherapy protocol for psoriasis and other dermatoses and for making the diagnosis of photosensitivity disorders.

Comparative Study of the Gross Interpretation of Phototesting and Objective Measurement with Using a Spectrophotometer for Patients with Psoriasis and Vitiligo Treated with Narrow-band UVB

BACKGROUND:Determination of the minimal erythema dose (MED) is important for developing a phototherapy protocol and to diagnosis photosensitivity disorders. But obtaining a precise and reproducible MED is quite difficult because a phototest for erythema is based on subjective assessment. OBJECTIVE: The objective of our study was to compare the gross interpretation of a phototest and the objective measurement using a spectrophotometer for determining the parameters of cutaneous narrow-band UVB (NBUVB) therapy. METHODS: A total of 14 psoriasis and 10 vitiligo patients who receiving NBUVB phototherapy with skin types III and IV were selected for this study. To perform phototesting, ten sites on the skin of the back were vertically exposed to a series of 10 NBUVB doses among 14 doses between 340 and 1,400 mJ/cm2. We interpreted the gross findings of erythema and measured the L*a*b* values with using a spectrophotometer at each phototest spot and at the control skin. Also, we evaluate the relationship between the gross presentation and the spectrophotometric analysis by delta E for the assessment of the minimal perceptible erythema (MPE) and MED. RESULTS: For all the subjects, the MEDs were measured in the 490~1,000 mJ/cm2 range. The average of the colorimetric values for the control skin were L*: 64.8, a*: 7.9 and b*: 19.8. Among them, the L* value and MED value were shown to be inversely correlated, and as the L* value was decreased, the MED was increased. For the MPE, the delta E, which was the color difference of the normal skin and the phototest area, was within the range of 1.5~3.0 in 17 of the 21 patients, and 4 patients were within the range of 1.0~1.5. For the MED, among the 21 patients, the delta E of 17 patients was within the range of 3.0~6.0, and 4 patients were within the range of 6.0~12.0. CONCLUSION: A spectrophotometer enables UV erythema to be assessed objectively and quantitatively, and this can compensate for the disadvantages of subjective gross interpretation when determining the MED. Delta E is a good novel and objective indicator for determining the MPE and MED. So, a spectrophotometer is a very useful instrument for developing a phototherapy protocol for psoriasis and other dermatoses and for making the diagnosis of photosensitivity disorders.

The effect of various foods on the color stability of artificial teeth / 대한치과보철학회지

STATEMENT OF PROBLEM: Recently, as patients'expectation and interest for esthetics are increasing, concerns of esthetic restoration for removable dentures as well as fixed prosthodontics are also increasing. And the color stability of artificial teeth will affect a long term success rate of the denture. But the stain or discoloration of these artificial teeth as well as denture resin has caused esthetic problem. PURPOSE: This study was designed to evaluate the influence on color stability of artificial teeth when soy sauce, red pepper paste and coffee which many Koreans have eaten were applied. MATERIAL AND METHODS: For artificial teeth type (Endura Anterio(R), Physio Duracross(R), Trubyte Biotone(R)) selected for the study, 10 specimens each were soaked into individual beakers of soy sauce, red pepper paste, coffee and distilled water. And L*, a*, b* value were measured for evaluation of the color difference (delta E*) with spectrophotometer on the 1 day, 1 week, 2 weeks, 4 weeks and 8 weeks after immersion. RESULTS: 1. delta E* value of artificial teeth which were soaked in soy sauce and coffee was various according to soaking periods. However there was significant difference between Trubyte Biotone(R) and Physio Duracross(R) in red pepper paste regardless of soaking period (P < .05). 2. Except for 8 weeks of Endura Anterio(R), 4 weeks and 8 weeks of Physio Duracross(R), artificial teeth soaked in red pepper paste regardless of the type had significant difference of _E* value compared with other groups (P < .05). 3. a*, b* value of Endura Anterio(R) and Trubyte Biotone(R) which were soaked in red pepper paste had significant difference compared with the value of other group (P < .05). CONCLUSION: Red pepper paste had the greatest effect on color difference of artificial tooth. Physio Duracross(R) showed relatively less color difference than Trubyte Biotone(R) and Endura Anterio(R). But as delta E* difference were all less than 3.3, these artificial resin teeth seemed appropriate for clinical use.