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.

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.

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).

Colloid formation at waste plume fronts.

Highly saline and caustic tank waste solutions containing radionuclides and toxic metals have leaked into sediments at U.S. Department of Energy (DOE) facilities such as the Hanford Site (Washington state). Colloid transport is frequently invoked to explain migration of radionuclides and metals in the subsurface. To understand colloid formation during interactions between highly reactive fluids and sediments and its impact on contaminant transport, we simulated tank waste solution (TWS) leakage processes in laboratory columns at ambient and elevated (70 degrees C) temperatures. We found that maximum formation of mobile colloids occurred at the plume fronts (hundreds to thousands times higher than within the plume bodies or during later leaching). Concentrations of suspended solids were as high as 3 mass %, and their particle sizes ranged from tens of nanometers to a few micrometers. Calcium carbonate is always one of the dominant phases of the plume front colloids, while the other phases varied with solution pH and temperature. During infiltration of the leaked high-Na+ waste solution, rapid and completed Na+ replacement of exchangeable Ca2+ and Mg2+ from the sediment caused accumulation of these divalent cations at the moving plume front. Precipitation of supersaturated Ca2+/Mg2+-bearing minerals caused dramatic pH reduction atthe plume front. In turn, the reduced pH caused precipitation of other minerals. This understanding can help predict the behavior of contaminant trace elements carried by the tank waste solutions and could not have been obtained through conventional batch studies.

Visibility of trabecular structures in oral radiographs.

OBJECTIVES: To determine whether alveolar trabecular bone is visible and quantifiable in projection radiographs. Radiographic changes in oral trabecular bone have been studied as possible indications of bone loss, but in some previous studies, observed structures have been attributed entirely to the endosteal surface. METHODS: Computed radiography (CR) images of human mandibles in molar and pre-molar regions were compared with simulations calculated from high-resolution computed-tomography (CT) and micro-CT volumes. By digitally editing the CT volumes, the simulations were separated into trabecular and cortical components. High-pass-filtered CR images revealed structural details of cortical and trabecular bone. RESULTS: Trabecular bone constitutes as much as 38% of the total alveolar bone, and accounts for most of the observed alveolar fine structure. Several morphological types of fine structure can be distinguished. The noise in filtered images appears to be a meaningful measure of trabecular bone. CONCLUSION: Trabecular bone is highly visible in intraoral radiographs.

Comments on noise and resolution of the DenOptix radiography system.

OBJECTIVES: Relatively low signal/noise (S/N) ratios, which are not substantiated by the results reported here, have been reported for the DenOptix digital intraoral radiography system. Unexplained poor performance has also been reported for imaging of the gingival tissue. I sought to discover the probable sources of the discrepancies and to present data on the effects of pixel size and screen type on noise and resolution. Methods. S/N ratios were measured with an aluminum phantom, and noise was measured with a step-wedge. The radiographs were scanned with both default and special, manufacturer-supplied software to obtain 8-bit rescaled data and 16-bit raw data. The data were compared with previously published data for the DenOptix and Digora systems. RESULTS: The S/N ratios of up to 17 obtained here were much higher than previously reported. Previously reported low ratios and poor performance for the imaging of gingival tissue were likely caused by digital clipping of 8-bit images, which should not affect bony tissue images in normal clinical radiographs. With nonstandard white phosphor screens, S/N ratios of up to 18 were observed, with only a minor loss of resolution. For the smallest pixel size (42 micro m), resolutions of > or =10 line-pairs/mm and > or =8 line-pairs/mm were observed for standard blue and white phosphor screen types. If the smallest pixel size is selected, the noise increases by only 25%, which is much less than the theoretical increase. CONCLUSIONS: In terms of both noise and resolution, the DenOptix system compares favorably with the Digora system. S/N ratios for the DenOptix system are comparable with the best of 6 previously tested systems. With the DenOptix system, the smallest pixel size produces both the best resolution and the best noise characteristics. The selection of 16-bit images prevents digital clipping of 8-bit images.