A direct comparison of quantitative microradiography and microhardness profiles was made using artificial caries-like lesions in human enamel. Tooth crowns with lesions were cut in half through the center of the lesions and opposing halves were assessed by one of the techniques, from the anatomical surface, across the lesion, and into the underlying enamel. A linear relationship was found between volume percent mineral determined by microradiography and the square root of the Knoop Hardness Number assessed by microhardness testing in the mineral range of 40–90 volume percent. The relationship also holds for sound dentine. It is concluded that either technique can be used to measure mineral profiles through carious lesions as a result of demineralization and presumably remineralization.

BackgroundThe objective of this study was to translate and to test the reliability and validity of the 12-item General Health Questionnaire (GHQ-12) in Iran.MethodsUsing a standard 'forward-backward' translation procedure, the English language version of the questionnaire was translated into Persian (Iranian language). Then a sample of young people aged 18 to 25 years old completed the questionnaire. In addition, a short questionnaire containing demographic questions and a single measure of global quality of life was administered. To test reliability the internal consistency was assessed by Cronbach's alpha coefficient. Validity was performed using convergent validity. Finally, the factor structure of the questionnaire was extracted by performing principal component analysis using oblique factor solution.ResultsIn all 748 young people entered into the study. The mean age of respondents was 21.1 (SD = 2.1) years. Employing the recommended method of scoring (ranging from 0 to 12), the mean GHQ score was 3.7 (SD = 3.5). Reliability analysis showed satisfactory result (Cronbach's alpha coefficient = 0.87). Convergent validity indicated a significant negative correlation between the GHQ-12 and global quality of life scores as expected (r = -0.56, P < 0.0001). The principal component analysis with oblique rotation solution showed that the GHQ-12 was a measure of psychological morbidity with two-factor structure that jointly accounted for 51% of the variance.ConclusionThe study findings showed that the Iranian version of the GHQ-12 has a good structural characteristic and is a reliable and valid instrument that can be used for measuring psychological well being in Iran.

The anti-caries activity of fluoride is contributed to in several ways. Two major aspects of fluoride action are (i) the inhibition of demineralization at the crystal surfaces within the tooth, and (ii) the enhancement of subsurface remineralization resulting in arrestment or reversal of caries lesions. Fluoride present in the aqueous phase at the apatite crystal surface may play a determining role in the inhibition of enamel or dentin demineralization. In one part of the present study, the initial dissolution rate of synthetic carbonated-apatite in acetate buffers was measured with fluoride present in the buffer in the 0-2.6 mmol/L (0-50 ppm) range. Inhibition of demineralization was shown to be a logarithmic function of the fluoride concentration in solution. In the second part of the present study, an in vitro pH-cycling model was used for determination of the effect on net de/remineralization of enamel by treatment solutions containing fluoride in the 0-26 mmol/L (0-500 ppm) range. The net mineral loss was shown to be negatively related to the logarithm of the fluoride concentration. These studies have demonstrated an exponential quantitative relationship between fluoride concentration and inhibition of apatite demineralization or enhancement of remineralization. The clinical implications are (i) that simply increasing fluoride concentration may not necessarily give increased cariostatic benefit, and (ii) that improving the means of delivery of relatively low fluoride concentrations for longer times should be more appropriate for enhancing clinical efficacy.

BackgroundOcular biometric parameters can be influenced by race, ethnicity, and genetics; their differences across different populations can probably explain differences in refractive errors in these populations. The aim of this study is to determine the normal range of axial length, anterior chamber depth, lens thickness, and vitreous chamber depth in the population of Shahroud in the north of Iran.MethodsIn the first phase of Shahroud Eye Cohort Study, the 40–64 year old population were sampled cross-sectionally; 6311 were invited and 5190 (82.2%) participated in the study. Biometric examinations were done using the LENSTAR/BioGraph (WaveLight AG, Erlangen, Germany) after vision tests and before cycloplegic refraction tests. Any type of eye surgery, extensive pterygium, and lack of cooperation were used as exclusion criteria, and analyses were done with data from 4869 eyes.ResultsWe found a mean axial length of 23.14 mm (95% confidence interval [CI], 23.11-23.17), mean anterior chamber depth of 2.62 mm (95% CI, 2.60-2.63), mean lens thickness of 4.28 mm (95% CI, 4.27-4.29), and the mean vitreous chamber depth was 15.72 mm (95% CI, 15.70-15.75).Kolmogorov-Smirnov tests showed that the distribution of axial length, anterior chamber depth, lens thickness, and vitreous chamber depth significantly differed from normal; axial length and vitreous chamber depth demonstrated a leptokurtic distribution as well.Axial length, anterior chamber depth, and vitreous chamber depth significantly decreased with age, and lens thickness significantly increased with age (p < 0.001). All indices were significantly higher in men.ConclusionsThe distributions of axial length, vitreous chamber depth, and lens thickness are reported for the first time in an Iranian adult population. Compared to other studies, axial length was in the mid range, nonetheless, studying axial length components showed that the Iranian population had smaller anterior chamber depth and lens thickness. Age and gender were significantly associated with all indices assessed in this study.

Background: An earthquake measuring 6.3 on the Richter scale struck the city of Bam in Iran on the 26th of December 2003 at 5.26 A.M. It was devastating, and left over 40,000 dead and around 30,000 injured. The profound tragedy of thousands killed has caused emotional and psychological trauma for tens of thousands of people who have survived. A study was carried out to assess psychological distress among Bam earthquake survivors and factors associated with severe mental health in those who survived the tragedy.