Presence and leaching of bisphenol a (BPA) from dental materials

<p>BPA has been reported to leach from some resin based dental restorative materials and materials used for orthodontic treatment. To confirm and update previous findings, especially in light of the new temporary lower threshold value for tolerable daily BPA intake, we have investigated the leaching of BPA from 4 composite filling materials, 3 sealants and 2 orthodontic bonding materials. The materials were either uncured and dissolved in methanol or cured. The cured materials were kept in deionized water for 24 hours or 2 weeks. Samples were subsequently analyzed by ultra-performance liquid chromatography coupled to mass spectrometry (UPLC-MS-MS). The composite filling material Tetric EvoFlow^® and the fissure sealant DELTON^® showed significantly higher levels of BPA leaching compared to control samples for all test conditions (uncured, 24 h leaching and 2 weeks leaching). There were no significant differences in amount of leached BPA for any of the tested materials after 24 hours compared to 2 weeks. These results show that BPA is still released from some dental materials despite the general concern about potential adverse effects of BPA. However, the amounts of BPA were relatively low and most likely represent a very small contribution to the total BPA exposure.</p

Blood 25-hydroxyvitamin D and percent mammographic density (%MD).

<p>¹Adjusted by age (continuous), BMI (continuous), calcium and energy intake (continuous) (estimated from diet including supplements).</p><p>Blood 25-hydroxyvitamin D and percent mammographic density (%MD).</p

Month the mammogram was taken and percent mammographic density (%MD) by geographic region of usual area of residence.

<p>¹Usual residence, South, i.e., Akershus and Hordaland counties 60°N and North, i.e., Nordland county 67°N</p><p>²n = 268 missing values on month the mammogram was taken(season)</p><p>³Least square means adjusted for age (continuous), body mass index (continuous), estrogen and progestin therapy (never, past and current), parity (0, 1,2 or ≥3),</p><p>Educational level (≤10 years, 11–14 years and ≥15 years) and study year (0 = 2004 or 1 = 2006/07).</p><p>Month the mammogram was taken and percent mammographic density (%MD) by geographic region of usual area of residence.</p

Percent mammographic density (%MD) by quartiles of vitamin D, calcium and energy intakes, stratified by month the mammogram was taken.

<p>¹The majority of the mammograms in 2004 were taken in October-December. Because there were so few mammograms in June-August we added September to this category</p><p>²Total = diet plus supplements</p><p>³Least square means adjusted for age (continuous), body mass index (continuous), estrogen and progestin therapy (never, past and current), parity (0, 1,2 or ≥3),</p><p>Educational level (≤10 years, 11–14 years and ≥15 years) and study year (0 = 2004 or 1 = 2006/07) energy with supplements (continuous), vitamin D with supplements and calcium (where appropriate).</p><p>Percent mammographic density (%MD) by quartiles of vitamin D, calcium and energy intakes, stratified by month the mammogram was taken.</p

Percent mammographic density (%MD) by total vitamin D intake (quartiles), stratified by total calcium intake (quartiles) (N = 3114).

<p>¹Total = diet plus supplements</p><p>²Least square means adjusted for age (continuous), body mass index (continuous), estrogen and progestin therapy (never, past and current), parity (0, 1,2 or ≥3)</p><p>Educational level (≥10 years, 11–14 years and 15+ years), study year (0 = 2004 or 1 = 2006/07), calcium with supplements (continuous), and energy with supplements (continuous).</p><p>Percent mammographic density (%MD) by total vitamin D intake (quartiles), stratified by total calcium intake (quartiles) (N = 3114).</p

Mammographic percent density (%MD) by month the mammogram was taken, vitamin D intake (quartiles), and calcium intake (quartiles) in women overall, <55 and > = 55 years at mammography.

<p>¹Least square means mutually adjusted (for age (continuous), body mass index (continuous), estrogen and progestin therapy (never, past and current), parity (0, 1,2 or ≥3), educational level (≤10 years, 11–14 years and ≥15 years) and study year (0 = 2004 or 1 = 2006/07)</p><p>Calcium and energy (continuous) (estimated from diet including supplements)</p><p>²Total = diet plus supplements</p><p>³Likelihood ratio test is done on a nested model including variables as described in ¹ compared to a model including sinusoidal function on month the mammogram was taken.</p><p>Mammographic percent density (%MD) by month the mammogram was taken, vitamin D intake (quartiles), and calcium intake (quartiles) in women overall, <55 and > = 55 years at mammography.</p