Rex A. Couture

Cross-sectional Study of Vitamin D and Calcium Supplementation Effects on Chronic Periodontitis

BACKGROUND A low dietary intake of vitamin D and calcium hastens bone loss and osteoporosis. Because vitamin D metabolites may also alter the inflammatory response and have antimicrobial effects, we studied whether the use of vitamin D and calcium supplements affects periodontal disease status. METHODS A cohort of 51 subjects receiving periodontal maintenance therapy was recruited from two dental clinics; 23 were taking vitamin D (>or=400 IU/day) and calcium (>or=1,000 mg/day) supplementation, and 28 were not taking such supplementation. All subjects had at least two interproximal sites with >or=3 mm clinical attachment loss. Daily calcium and vitamin D intake (from food and supplements) were estimated by nutritional analysis. The following clinical parameters of periodontal disease were recorded for the mandibular posterior teeth: gingival index, probing depth, cemento-enamel junction-gingival margin distance (attachment loss), bleeding on probing, and furcation involvement. Posterior photostimulable-phosphor bitewing radiographs were taken to determine cemento-enamel junction-alveolar crest distances (alveolar crest height loss). Data were analyzed with a repeated-measures multivariate analysis of variance. RESULTS Compared to subjects who did not take vitamin D and calcium supplementation, supplement takers had shallower probing depths, fewer bleeding sites, lower gingival index values, fewer furcation involvements, less attachment loss, and less alveolar crest height loss. The repeated-measures analysis indicated that collectively these differences were borderline significant (P = 0.08). CONCLUSIONS In these subjects receiving periodontal maintenance therapy, there was a trend for better periodontal health with vitamin D and calcium supplementation. More expanded longitudinal studies are required to determine the potential of this relationship.

One-Year Effects of Vitamin D and Calcium Supplementation on Chronic Periodontitis

BACKGROUND A previous study reported by this group found that patients in periodontal maintenance programs taking vitamin D and calcium supplementation had a trend for better periodontal health compared to patients not taking supplementation. The objective of the present study is to determine, for the same cohort of subjects, whether such differences persist over a 1-year period. METHODS Fifty-one patients enrolled in maintenance programs from two dental clinics were recruited. Of these, 23 were taking vitamin D (≥400 IU/day) and calcium (≥1,000 mg/day) supplementation, and 28 were not. All subjects had at least two interproximal sites with ≥3 mm clinical attachment loss. For mandibular-posterior teeth, gingival index, plaque index, probing depth, attachment loss, bleeding on probing, calculus index, and furcation involvement were evaluated. Photostimulable-phosphor, posterior bitewing radiographs were taken to assess alveolar bone. Daily vitamin D and calcium intakes were estimated by nutritional analysis. Data were collected at baseline, 6 months, and 12 months. RESULTS Total daily calcium and vitamin D intakes were 1,769 mg (95% confidence interval, 1,606 to 1,933) and 1,049 IU (781 to 1,317) in the taker group, and 642 mg (505 to 779) and 156 IU (117 to 195) in the non-taker group, respectively (P <0.001 for both). Clinical parameters of periodontal health improved with time in both groups (P <0.001). When clinical measures were considered collectively, the differences between supplement takers and non-takers had the following P values: baseline (P = 0.061); 6 months (P = 0.049); and 12 months (P = 0.114). After adjusting for covariates, the P values for the effect of supplementation were as follows: baseline (P = 0.028); 6 months (P = 0.034); and 12 months (P = 0.058). CONCLUSIONS Calcium and vitamin D supplementation (≤1,000 IU/day) had a modest positive effect on periodontal health, and consistent dental care improved clinical parameters of periodontal disease regardless of such supplements. Our findings support the possibility that vitamin D may positively impact periodontal health and confirm the need for randomized clinical trials on the effects of vitamin D on periodontitis.

X-ray fluorescence analysis of silicate rocks using fused glass discs and a side-window Rh source tube: accuracy, precision and reproducibility☆

Abstract In this paper, we provide a detailed account of our sample fusion, calibration and instrumentation methods for major-element whole-rock analysis by XRF, and we discuss several aspects of sample preparation and instrument performance that are important considerations for accurate analysis. The fusion procedure involves moderate capital costs and is easy to apply, yielding flat, polished, homogeneous glass discs as cast. The calibration method utilizes a least-squares procedure that rigorously fits data according to both compositional and counting statistical uncertainties. We use a side-window Rh tube for analyzing major elements (including Na) and employ real-time testing for constant count rate to reject spurious results. The methods result in excellent analytical precision and reproducibility. The standards used for calibration lie within compositional and counting statistical uncertainties of best-fit straight lines. Analyses of replicate discs and repeated analyses of single discs show excellent long-term reproducibility over several months, approaching counting statistical uncertainties in several cases. Comparison with independent measurements made by other laboratories using instrumental neutron activation and X-ray fluorescence analyses shows excellent agreement with our results. A side-window Rh tube gives increased detection limits for most major elements, but otherwise shows little difference in precision compared to a Cr tube. This means that major and trace elements can be analyzed without changing X-ray sources, which provides saving in terms of time and money, as well as being a convenience to the analyst.

Calcium and vitamin D use among adults in periodontal disease maintenance programmes.

Objectives To determine the level of calcium and vitamin D oral supplementation in patients in periodontal disease maintenance programmes.Design Convenience survey.Setting St. Louis Metropolitan region.Subjects and methods Patients (n = 228) in two university-based, periodontal disease maintenance programmes.Main outcome measures Reported amounts of oral calcium and vitamin D supplementation were tested for differences based on gender and race.Results The last published recommended daily intakes from the United States (US) Food and Nutrition Board (FNB) for adults >50 years of age are 1,200 mg calcium and 400 IU vitamin D (or 600 IU if over 70). The mean age of the 228 patients (125 females and 103 males) was 63.6 ± 11.0 years (standard deviation). Of the 228 patients surveyed: (1) 204 (89%) were >50 years of age and of these, only 15 (7%) met the US FNBs recommended intakes of calcium and vitamin D from supplementation; (2) 138 (66%) reported that they took no oral supplementation, with significantly more males (n = 82) than females (n = 56) not taking supplementation (p = 0.03); (3) 88 (39%) took calcium supplementation, with females (947 ± 511 mg/day) taking significantly (p <0.001) more than males (632 ± 907 mg/day); and (4) 66 (29%) took vitamin D supplementation, with females(420 ± 227 IU/day) taking approximately the same amount as males (443 ± 317 IU/day, p >0.05). The amounts of oral supplementation did not vary with race (p >0.05).Conclusion The use of calcium and vitamin D supplementation has been promoted for years, yet the numbers of adults taking supplements remains low and the level of supplementation varies greatly. Knowledge of the benefits of supplementation needs to be better disseminated and research needs to be conducted to determine optimal levels of calcium and vitamin D supplementation.

A reexamination of absorption and enhancement effects in X-ray fluorescence trace element analysis

Abstract In this paper, sample mass-absorption corrections for X-ray fluorescence trace element analysis are reexamined and a new approach is presented that is more accurate and more versatile than current methods. A method based on Compton scattering of a tube line is widely used because it is simple and does not require knowledge of the complete sample composition. The equivalent-wavelength method is sometimes used instead, especially if there is a major element absorption edge between the wavelengths of the Compton peak and the characteristic analyte radiation. Both methods suffer from difficulties in correcting for absorption edges and for enhancement by secondary fluorescence. In addition, the necessary assumption that the ratio of mass-absorption coefficients of any two elements is approximately independent of wavelength is surprisingly inaccurate. A series of examples demonstrates that in some cases large analytical errors may result. Methods based on the new approach completely and automatically correct for absorption edges and secondary fluorescence, without introducing such errors. In contrast to current methods, a complete major element analysis is not necessary. Thus, rapid determination of concentration ratios, such as Cr/Fe and V/Fe in oxide ores, Ba/Fe in Fe-rich hydrothermal deposits, and Sr/Ca in carbonates, is possible. In an experimental test, accuracy of better than 1% was demonstrated for analysis of V in Fe-rich samples. A proposed coefficient approximation was shown to give accuracy of 2% or better (excluding experimental errors) for Rb, Ni, Ba, and Cr over an extremely wide range of sample compositions.

Quantitative dental radiography with a new photostimulable phosphor system

OBJECTIVE The purposes of this report are to present a quantitative model for digital oral radiography and to evaluate a new photostimulable phosphor system for bone mass measurements. STUDY DESIGN Noise, linearity, and precision were measured from stepwedge images and blank images through use of a special least-squares calibration method. The model was used to estimate lower limits of detection for observing small changes in bone mineral content. RESULTS The response was virtually linear, and the noise level of 2% to 3% is less than that of digitized film images. The precision of measurements averaged over a region of interest was generally better than 0.5%. CONCLUSIONS If the scatter fraction is measured for each patient, bone loss can be measured by using only extraoral standards. Assuming a scatter fraction of 50% and considering only instrumental errors, the detection limit is <0.02 g/cm(2) for large image areas (> or =7 mm(2)) and <0.3 mg over areas of 1 mm(2) or smaller.

Alveolar bone measurement precision for phosphor-plate images

OBJECTIVES The aim was to demonstrate methods for determining measurement precision and to determine the precision of alveolar bone measurements made with a vacuum-coupled positioning device and phosphor plate images. STUDY DESIGN Subjects were rigidly attached to the x-ray tube by means of a vacuum coupling device and custom cross-arch bite plates. Original and repeat radiographs (taken within minutes of each other) were obtained of the mandibular posterior teeth of 51 subjects, and cementoenamel junction-alveolar crest (CEJ-AC) distances were measured on both sets of images. In addition, x-ray transmission (radiodensity) and AC height differences were determined by subtracting one image from the other. Image subtractions and measurements were performed twice. Based on duplicate measurements, the root mean square standard deviation (precision) and least significant change (LSC) were calculated. LSC is the magnitude of change in a measurement needed to indicate that a true biologic change has occurred. RESULTS The LSCs were 4% for x-ray transmission, 0.49 mm for CEJ-AC distance, and 0.06 mm for crest height. CONCLUSION The LSCs for our CEJ-AC and x-ray transmission measurements were similar to what has been previously reported. The LSC for AC height (determined with image subtraction) was <0.1 mm. Compared with findings from earlier studies, this represents a highly precise measurement of AC height. The methods demonstrated for calculating LSC can be used by investigators to determine how large changes in radiographic measurements need to be before the changes can be considered to be (with 95% confidence) true biologic changes and not noise (i.e., equipment/observer error).