Radiographic evaluation of marginal bone maintenance around tissue level implant and bone level implant: a randomised controlled trial. A 1‐year follow‐up

The etiologic factors associated with crestal bone loss have not been comprehensively clarified. Several theories exist as to the reason for the observed changes in crestal bone height following implant restoration. In the 1990s, the wide‐diameter implants were commercially introduced. Initially, the implants were restored with standard‐diameter abutments because of lack of matching prosthetic components. Long‐term radiographic follow‐up of these ‘platform‐switched’ restored wide‐diameter dental implants has demonstrated a smaller‐than‐expected vertical change in the crestal bone height around these implants that is typically observed around implants restored conventionally with prosthetic components of matching diameters. The aim of this randomised controlled study was to assess radiographically marginal bone level alterations in implants restored according to the platform‐switching concept compared with traditionally restored implants. Fifty‐four subjects to participate in this randomised controlled study were selected. Two groups were assigned at random: control group (56 implants were restored with standard matching‐diameter abutments) and test group (58 implants were restored with medialised abutments). X‐ray explorations were taken for peri‐implant bone level at the minute the last cementing of the prosthesis and at 1‐year follow‐up. NHI Image was used to digitally process and manipulate the radiographic images and perform the measurements. Mean of bone loss with platform‐switching implants was ?0·01 mm, and the mean of bone loss with standard platform implant was 0·42 mm. Outcomes of this study indicated that the platform‐switching design could preserve the crestal bone levels to 1‐year follow‐up. There was a statistically significant difference in marginal bone loss.     

Osseous metastases: drugs that enhance bone integrity and prevent adverse skeletal events

More than 400,000 cancer patients in the USA contend with bone metastases on an annual basis. These patients often suffer pain, a decline in quality of life, and a shortened survival. As a result, over the past several years, efforts to enhance bone integrity in patients with osseus metastases have become a major research priority. This review discusses the evolving role of bisphosphonates and their side effects, highlights other pharmacological interventions aimed at enhancing bone integrity, and reviews other pragmatic approaches to prevent worsening pain and fractures, as derived from a single institution case series of patients with problematic rib metastases.     

qMRI relaxometry of mandibular bone marrow: A monomodal distribution in sickle cell disease

Purpose:

To identify and characterize sickle cell disease (SCD)‐related changes in the composition of mandibular bone marrow using qMRI relaxometry histograms.

Materials and Methods:

Thirteen SCD patients and 17 controls underwent brain MR imaging with the mixed turbo spin‐echo (TSE) pulse sequence at 1.5T. The mandible was manually segmented and divided into body, angle, ramus, and condyle. T1 and T2 histograms of each mandible were modeled with Gaussian functions. The relaxation time histogram peaks were calculated, and the number of monomodal versus bimodal curves was compared.

Results:

SCD patients exhibited monomodal distributions on both T1 and T2 histograms, consistent with a composition of predominantly red hematopoietic marrow. Eighty‐eight percent of mandibles in control subjects exhibited a bimodal distribution in T1 and all showed a bimodal distribution in T2, indicating mixed but predominantly yellow marrow composition. The second peak in control subjects was shorter in T1 and longer in T2, consistent with yellow marrow composition.

Conclusion:

Instead of physiological fatty replacement, SCD patients exhibit red marrow persistence in the mandible, likely due to the increased demand for hematopoiesis. This phenomenon can be manifested by a monomodal curve in both T1 and T2 relaxometric histograms. J. Magn. Reson. Imaging 2013;37:1182–1188. © 2012 Wiley Periodicals, Inc.     

Effect of 1α-Hydroxyvitamin D3 on Cancellous Bone Matrix: An Experimental Study on Adult Rats

Two groups of adult male rats were treated perorally for 6 weeks with 0.1 μg and 1.0 μg of 1a-hydroxyvitamin D₃ (la-OH-D₃), respectively. The effect of the treatment on cancellous bone matrix was studied by chemical analysis and morphometric measurements. The effect of the 1.0 μg dose on the inorganic composition, and on the calcification of the cancellous bone matrix, was significantly more pronounced, decreasing the amount of glycosaminoglycans. The lower dose level, 0.1 μg of la-OH-D₃, increased the collagen metabolism, whereas the higher dose level did not. The amount of cancellous bone determined morphometrically increased significantly during treatment with both dose levels. 1a-OH-D₃, converted in the organism to the hormonal form 1.25 (OH)₂D₃, induces new bone formation, probably by direct influence on the cancellous bone tissue itself.     

Effects of air tourniquet on the antibiotics concentration,in bone marrow,injected just before the start of operation

Abstract

Infection is one of the most serious complications after artificial arthroplasty. In order to establish the effective prevention for after operative infection, we measured the serum and bone marrow blood cefmetazole (CMZ) concentration time dependently (1?g CMZ, one shot). Furthermore, we studied the effect of air tourniquet on CMZ transmit into bone marrow blood. Thirteen knees with total knee arthroplasty (TKA) were included in the study. As a control group, 11 hips with total hip arthroplasty (THA) were also included. In TKA, air tourniquet was used during operation in all cases. Just before the start of the operation, 1?g CMZ was injected intravenously (one shot). Subsequently we sampled peripheral blood and bone marrow blood time dependently. Cefmetazole concentration was measured with HPLC. In the THA group, serum and bone marrow blood CMZ concentration showed almost the same time-dependent change. On the other hand, in the TKA group we could not detect CMZ in bone marrow blood in cases where CMZ was injected within 8?min before starting use of an air tourniquet. If CMZ was injected more than 10?min before starting use of the air tourniquet, CMZ concentration in bone marrow blood was much lower than minimum inhibitory concentration (MIC) for Staphylococcus aureus; but after releasing the air tourniquet, CMZ concentration in bone marrow blood was higher than MIC for S. aureus. These data suggested that our injection method is effective for prevention of infection both during and just after operation in the THA but in the TKA, CMZ should be injected more than 10?min before starting to use the air tourniquet.     

The impact of proton pump inhibitors on bone regeneration and implant osseointegration

Abstract

Proton pump inhibitors (PPIs) have become known for the treatment of gastric-acid related disorders. Similar to any other drugs, PPIs have possible adverse reactions, being associated with bone fractures, infections, kidney disease, mineral deficiency, dementia, and pneumonia. Multiple analyses have stated that PPIs therapy may affect bone regeneration and osseointegration process, causing an increased risk of bone fracture, deterioration of bone metabolism and impaired bone healing. In this review, we emphasized the current literature regarding the influence of proton pump inhibitors in the bone regeneration process. Results from the studies suggest a link between PPIs intake and bone regeneration, but several concerns are raised regarding inadequate recipient bone, surgical trauma, limitations on the titanium surface, comorbidities or interference with other pharmacological agents. Further studies are needed to determine whether the impaired bone regeneration process is due to PPI or coexisting factors.