Short-term effects of initial, nonsurgical periodontal treatment (hygienic phase)

. Longitudinal studies have reported the effect of various modalities of periodontal surgery on pocket depth and attachment levels related to pretreatment measurements. However, possible changes in these measurements as a result of scaling, oral hygiene improvements and occlusal adjustment during the hygienic phase were not considered. The purpose of the present study was to examine the short-term effect of treatment of the hygienic phase in 90 patients with some pockets extending 4 mm or more apically to the CEJ. Pretreatment pocket depths and attachment levels related to the CEJ were measured by a thin probe in five sites at all 2,355 teeth in the sample. Scaling, root planing, instruction in oral hygiene and occlusal adjustment were completed during four to six sessions for each patient. Four weeks after completion of the hygienic phase, all variables were recorded. Mean measurements for pocket depths 1–3 mm, 4–6 mm. and ≥ 7 mm prior to treatment were compared to their posttreatment scores. Pocket depth decreased significantly for pockets extending 4 mm or more apically to the FGM. For pockets 4–6 mm there was a mean difference in pocket depth of 0.%± 0.47 mm ( P < .0001) between pretreatment and post-treatment observations. For pockets 7 mm or greater the mean difference was 2.22 ± 1.35 mm ( P < .0001). Reduction in depth of pocket and improvement in attachment levels were related to the initial level of severity. Pocket reduction was in part due to the improvement in attachment levels. This study has demonstrated that the clinical severity of periodontitis is reduced significantly 1 month following the hygienic phase of periodontal therapy, and that need for surgical pocket treatment cannot be assessed properly until completion of the hygienic phase of treatment.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72964/1/j.1600-051X.1980.tb01963.x.pd

Observation of Reduced Homeostatic Metabolic Activity and/or Coupling in White Matter Aging

BACKGROUND AND PURPOSE: Transvascular water exchange plays a key role in the functional integrity of the blood brain barrier (BBB). In white matter (WM), a variety of imaging modalities have demonstrated age-related changes in structure and metabolism, but the extent to which water exchange is altered remains unclear. Here, we investigated the cumulative effects of healthy aging on WM capillary water exchange. METHODS: 38 healthy adults (aged 36–80 years) were studied using 7T dynamic contrast enhanced MRI. Blood volume fraction (v(b)) and capillary water efflux rate constant (k(po)) were determined by fitting changes in the (1)H(2)O longitudinal relaxation rate constant (R(1)) during contrast agent bolus passage to a two-compartment exchange model. WM volume was determined by morphometric analysis of structural images. RESULTS: R(1) values and WM volume showed similar trajectories of age-related decline. Among all subjects, v(b) and k(po) averaged 1.7 (± 0.5) mL/100 g of tissue and 2.1 (± 1.1) s(−1), respectively. While v(b) showed minimal changes over the 40-year age span of participants, k(po) declined 0.06 s(−1) (ca. 3%) per year (r= −0.66; P< .0005), from near 4 s(−1) at age 30 to ca. 2 s(−1) at age 70. The association remained significant after controlling for WM volume. CONCLUSIONS: Previous studies have shown that k(po) tracks Na(+),K(+)-ATPase activity-dependent water exchange at the BBB and likely reflects neuro-glio-vascular unit (NGVU) coupled metabolic activity. The age-related decline in k(po) observed here is consistent with compromised NGVU metabolism in older individuals and the dysregulated cellular bioenergetics that accompany normal brain aging

Gradient nonlinearity effects on upper cervical spinal cord area measurement from 3D T-1-weighted brain MRI acquisitions

Purpose: To explore (i) the variability of upper cervical cord area (UCCA) measurements from volumetric brain 3D T1 -weighted scans related to gradient nonlinearity (GNL) and subject positioning; (ii) the effect of vendor-implemented GNL corrections; and (iii) easily applicable methods that can be used to retrospectively correct data. Methods: A multiple sclerosis patient was scanned at seven sites using 3T MRI scanners with the same 3D T1 -weighted protocol without GNL-distortion correction. Two healthy subjects and a phantom were additionally scanned at a single site with varying table positions. The 2D and 3D vendor-implemented GNL-correction algorithms and retrospective methods based on (i) phantom data fit, (ii) normalization with C2 vertebral body diameters, and (iii) the Jacobian determinant of nonlinear registrations to a template were tested. Results: Depending on the positioning of the subject, GNL introduced up to 15% variability in UCCA measurements from volumetric brain T1 -weighted scans when no distortion corrections were used. The 3D vendor-implemented correction methods and the three proposed methods reduced this variability to less than 3%. Conclusions: Our results raise awareness of the significant impact that GNL can have on quantitative UCCA studies, and point the way to prospectively and retrospectively managing GNL distortions in a variety of settings, including clinical environments. Magn Reson Med 79:1595-1601, 2018. © 2017 International Society for Magnetic Resonance in Medicine