Continuous renal replacement therapy in the treatment of severe hyperkalemia: An in vitro study.

INTRODUCTION: Continuous renal replacement therapy is not presently recommended in the treatment of life-threatening hyperkalemia. There are no specific recommendations in hemodialysis to treat hyperkalemia. We hypothesized an in vitro model may provide valuable information on the usefulness of continuous renal replacement therapy to treat severe hyperkalemia. METHODS: A potassium-free solute was used instead of diluted blood for continuous renal replacement therapy with a simulated blood flowrate set at 200 mL/min. The mode of elimination included continuous filtration, continuous dialysis, and continuous diafiltration using a flowrate of 4000 mL/min for continuous filtration and continuous dialysis modes, and a ratio of 2500/1500 in the continuous diafiltration mode. RESULTS: The mean initial potassium in the central compartment was 10.1 ± 0.4 mmol/L. The clearances in the continuous diafiltration, continuous filtration, and continuous dialysis were 3.4 ± 0.5, 3.6 ± 0.1, and 3.7 ± 0.1 L/h, respectively, not significantly different. Continuous dialysis resulted in the lowest workload for staff. Increasing the continuous dialysis flowrates from 2000 to 8000 mL/h increased clearance from 2.3 ± 0.3 to 6.2 ± 0.8 L/h. The delays in decreasing the potassium concentration to 5.5 mmol/L dropped from 120 to 45 min, respectively. Potassium eliminated in the first hour increased from 18 to 38 mmol that compared favorably with hemodialysis. Decrease in simulated blood flowrate from 200 to 50 mL/min moderately but significantly decreased the clearance from 3.7 to 3.0 L/h. CONCLUSION: Hyperkalemia is efficiently treated by continuous renal replacement therapy using the dialysis mode. Caution is needed to prevent the onset of severe hypokalemia within 40 min after initiation of the session.

[Transplantation of impacted canines]. / Transplantations des canines incluses.

Techniques for dental transplantation today are taking better advantage of the potential for healing of the periodontal ligament than in the past and have reduced the risk of ankylosis and root resorption to below 1.5%. The resulting improvement in prognosis has made it possible to more confidently plan procedures that include orthodontic treatment. Transplantations can offer a good end result in certain clinical situations that would otherwise be difficult to manage: ectopic teeth, transpositions, tooth trauma sequellae, advanced decay or advanced periodontitis, implanted hard to treat impacted teeth, and idiopathic ankylosis. This article describes the biological principles for transplantation using double periodontal ligament stimulation, explains the surgical techniques and provides several examples to expand on the treatment of impacted canines, whether or not they present with idiopathic ankylosis. Dental ankylosis is the fusion of the bone with the root. The idiopathic type occurs spontaneously before the eruption of the affected tooth. The etiology is unknown. Because the tooth becomes part of the process of osseous remodeling, it is progressively resorbed and then replaced by bony tissue. This process takes place rather quickly and weakens the tooth. Additionally, an early diagnosis makes it possible to plan a transplantation under favorable circumstances, as that is the only way to halt the ankylosis and to achieve an adequate implantation. In rare cases, the location of the ankylosis is surgically accessible and can be eliminated before resuming orthodontic traction.

Idiopathic ankylosis-resorption: diagnosis and treatment.

Dental ankylosis involves the fusion of root to bone. The idiopathic form occurs spontaneously before the eruption of the tooth concerned. Etiology is unknown. As the tooth becomes part of the bone-remodeling process, it is gradually resorbed and is replaced by bony tissue. The process is quite rapid and weakens the tooth. Thus, early diagnosis makes it possible to perform a graft in optimal conditions, this being the only means of severing the ankylosis and achieving adequate eruption. In some rare cases, the ankylotic point of fusion can be reached surgically and can be eliminated before orthodontic traction is initiated.

Tissue-engineered ligament: implant constructs for tooth replacement.

AIM: A tissue-engineered periodontal ligament (PDL) around implants would represent an important new therapeutic tool to replace lost teeth. The PDL is the key to tooth anchoring; it connects tooth root and alveolar bone, and it sustains bone formation. MATERIALS AND METHODS: Cells were isolated from PDL and cultured in a bioreactor on titanium pins. After the formation of multiple cellular layers, pins were implanted in enlarged dental alveolae. MAIN OUTCOME MEASURES: Cell-covered implants integrated without adverse effects, and induced bone in their vicinity. RESULTS: A histological examination of a dog model revealed that cells were arranged in a typical ligament-like fashion. In human patients, product safety was ascertained for 6-60 months. Probing and motility assessments suggested that the implants were well integrated with mechanical properties similar to those of teeth. Radiographs demonstrated the regeneration of deficient alveolar bone, the development of a lamina dura adjacent to a mineral-devoid space around the implant and implant migration in an intact bone structure. CONCLUSIONS: New tissue consistent with PDL developed on the surface of dental implants after implantation. This proof-of-principal investigation demonstrates the application of ligament-anchored implants, which have potential advantages over osseointegrated oral implants.

Tooth auto-transplantation with double periodontal ligament stimulation to replace periodontally compromised teeth.

BACKGROUND: The healing process of autotransplantation puts 2 different tissues in competition: the ligament on the root surface and the bone tissue of the alveolus. This study shows the effects of a protocol with 2 surgical stages, which promote ligament repair, inhibit adhesion between bone and dental root, and reduce the occurrence of the ankylosis-root resorption phenomenon. METHODS: Forty-three patients, 33 to 73 years old, received 47 transplantations of mature teeth (including retained teeth) during a 5-year period. During the first surgical step, the transplanted tooth is extracted, measured, immediately replaced in its origin site, and maintained with an original suture technique. The alveolus to which the tooth will be transplanted is adapted after extraction of the periodontally compromised tooth. The second surgery occurs at day 14, when regeneration of periodontal ligament (PDL) is at a maximum (first stimulation). The tooth is transplanted in its new alveolus and retained using the same suture technique to avoid a rigid splint and to create mechanical stimulation of the PDL (second stimulation). RESULTS: The results were 95.75% positive with normal PDL, with a 4.25% failure rate (transplant loss) and no ankylosis. Mean probing reduction was 8.37 +/- 3.0 mm. Mean radiographic bone gain was 7.73 +/- 4.32 mm. CONCLUSIONS: This study suggests that auto-transplantation with double PDL stimulation can be a viable treatment in clinical practice, especially to replace teeth with large periodontal lesions, deep furcation defects, and/or root fractures. This study shows the high potential of stimulated PDL to regenerate alveolar bone and periodontal structures in severe destruction sites.