Scaling and root planing with and without periodontal flap surgery

. Complete removal of calculus is a primary part of achieving a “biologically acceptable” tooth surface in the treatment of periodontitis. Rabbani et al. reported that a single episode of scaling did not completely remove subgingival calculus and that the deeper the periodontal pocket, the less complete the calculus removal. The purpose of the present study was to evaluate the effectiveness of scaling relative to calculus removal following reflection of a periodontal flap. Each of 21 patients who required multiple extractions had 2 teeth scaled, 2 teeth scaled following the reflection of a periodontal flap, and 2 teeth serve as controls. Local anesthesia was used. Following extraction, the % of subgingival tooth surfaces free of calculus was determined using the method described by Rabbani with a stereomicroscope. Results showed that while scaling only (SO) and scaling with a flap (SF) increased the % of root surface without calculus, scaling following the reflection of a flap aided calculus removal in pockets 4 mm and deeper. Comparison of SO versus SF at various pocket depths for % of tooth surfaces completely free of calculus showed 1 to 3 mm pockets to be 86% versus 86%, 4 to 6 mm pockets to be 43% versus 76% and >6 mm pockets to be 32% versus 50%. The extent of residual calculus was directly related to pocket depth, was greater following scaling only, and was greatest at the CEJ or in association with grooves, fossae or furcations. No differences were noted between anterior and posterior teeth or between different tooth surfaces.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73823/1/j.1600-051X.1986.tb01461.x.pd

Extravascular lung water assessed by transpulmonary single thermodilution and postmortem gravimetry in sheep

INTRODUCTION: Acute lung injury is associated with accumulation of extravascular lung water (EVLW). The aim of the present study was to compare two methods for quantification of EVLW: transpulmonary single thermodilution (EVLW(ST)) and postmortem gravimetric (EVLW(G)). METHODS: Eighteen instrumented and awake sheep were randomly assigned to one of three groups. All groups received Ringer's lactate (5 ml/kg per hour intravenously). To induce lung injury of different severities, sheep received Escherichia coli lipopolysaccharide 15 ng/kg per min intravenously for 6 hours (n = 7) or oleic acid 0.06 ml/kg intravenously over 30 min (n = 7). A third group (n = 4) was subjected to sham operation. Haemodynamic variables, including EVLW(ST), were measured using a PiCCOplus monitor (Pulsion Medical Systems, Munich, Germany), and the last measurement of EVLW(ST )was compared with EVLW(G). RESULTS: At the end of experiment, values for EVLW(ST )(mean ± standard error) were 8.9 ± 0.6, 11.8 ± 1.0 and 18.2 ± 0.9 ml/kg in the sham-operated, lipopolysaccharide and oleic acid groups, respectively (P < 0.05). The corresponding values for EVLWI(G )were 6.2 ± 0.3, 7.1 ± 0.6 and 11.8 ± 0.7 ml/kg (P < 0.05). Ranges of EVLWI(ST )and EVLWI(G )values were 7.5–21.0 and 4.9–14.5 ml/kg. Regression analysis between in vivo EVLW(ST )and postmortem EVLW(G )yielded the following relation: EVLW(ST )= 1.30 × EVLW(G )+ 2.32 (n = 18, r = 0.85, P < 0.0001). The mean bias ± 2 standard deviations between EVLW(ST )and EVLW(G )was 4.9 ± 5.1 ml/kg (P < 0.001). CONCLUSION: In sheep, EVLW determined using transpulmonary single thermodilution correlates closely with gravimetric measurements over a wide range of changes. However, transpulmonary single thermodilution overestimates EVLW as compared with postmortem gravimetry

Recombinant human activated protein C ameliorates oleic acid-induced lung injury in awake sheep

Introduction: Acute lung injury (ALI) may arise both after sepsis and non-septic inflammatory conditions and is often associated with the release of fatty acids, including oleic acid (OA). Infusion of OA has been used extensively to mimic ALI. Recent research has revealed that intravenously administered recombinant human activated protein C (rhAPC) is able to counteract ALI. Our aim was to find out whether rhAPC dampens OA-induced ALI in sheep. Methods: Twenty-two yearling sheep underwent instrumentation. After 2 days of recovery, animals were randomly assigned to one of three groups: (a) an OA+rhAPC group (n = 8) receiving OA 0.06 mL/kg infused over the course of 30 minutes in parallel with an intravenous infusion of rhAPC 24 mg/kg per hour over the course of 2 hours, (b) an OA group (n = 8) receiving OA as above, or (c) a sham-operated group (n = 6). After 2 hours, sheep were sacrificed. Hemodynamics was assessed by catheters in the pulmonary artery and the aorta, and extravascular lung water index (EVLWI) was determined with the single transpulmonary thermodilution technique. Gas exchange was evaluated at baseline and at cessation of the experiment. Data were analyzed by analysis of variance; a P value of less than 0.05 was regarded as statistically significant. Results: OA induced profound hypoxemia, increased right atrial and pulmonary artery pressures and EVLWI markedly, and decreased cardiac index. rhAPC counteracted the OA-induced changes in EVLWI and arterial oxygenation and reduced the OA-induced increments in right atrial and pulmonary artery pressures. Conclusions: In ovine OA-induced lung injury, rhAPC dampens the increase in pulmonary artery pressure and counteracts the development of lung edema and the derangement of arterial oxygenation

Inhaled aerosolised recombinant human activated protein C ameliorates endotoxin-induced lung injury in anaesthetised sheep

Introduction We recently demonstrated that intravenously infused recombinant human activated protein C (APC) attenuates ovine lipopolysaccharide (LPS)-induced lung injury. In this study, our aim was to find out whether treatment with inhaled aerosolised APC (inhAPC) prevents formation of increased lung densities and oedema and derangement of oxygenation during exposure to LPS. Methods: Sheep were anaesthetised during placement of intravascular introducers. After one to four days of recovery from instrumentation, the animals were re-anaesthetised, endotracheally intubated and mechanically ventilated throughout a six-hour experiment where the sheep underwent quantitative lung computed tomography. Sheep were randomly assigned to one of three groups: a sham-operated group (n = 8) receiving inhaled aerosolised saline from two hours after the start of the experiment; a LPS group (n = 8) receiving an intravenous infusion of LPS 20 ng/kg per hour and, after two hours, inhaled aerosolised saline over the next four hours; a LPS+inhAPC group (n = 8) receiving an intravenous infusion of LPS 20 ng/kg per hour and, after two hours, aerosolised APC 48 µg/kg per hour inhaled throughout the experiment. Data were analysed with analysis of variance; P less than 0.05 was regarded as significant. Results: An infusion of LPS was associated with a reduction of well-aerated lung volume and a rapid fall in arterial oxygenation that were both significantly antagonised by inhaled APC. Pulmonary vascular pressures and extravascular lung water index increased significantly during exposure to LPS, but inhaled APC had no effect on these changes. Conclusions: Inhalation of aerosolised APC attenuates LPSinduced lung injury in sheep by preventing a decline in the volume of aerated lung tissue and improving oxygenation

Recombinant human activated protein C attenuates endotoxin-induced lung injury in awake sheep

Introduction: Acute lung injury often complicates severe sepsis. In Gram-negative sepsis, bacterial endotoxin activates both coagulation and inflammation. Enhanced lung vascular pressures and permeability, increased extravascular lung water content and deteriorated gas exchange characterize ovine endotoxin-induced lung injury, a frequently used model of acute lung injury. Recombinant human activated protein C (rhAPC), with its anticoagulant, anti-inflammatory, fibrinolytic and antiapoptotic effects, reportedly reduces the respiratordependent days and the mortality of patients with severe sepsis. We speculate whether rhAPC antagonizes endotoxin-induced lung injury in sheep. Methods: Two groups of sheep were exposed to Escherichia coli endotoxin (lipopolysaccharide) 15 ng/kg/minute intravenously from 0 to 24 hours; one group received only lipopolysaccharide throughout (n = 8), and the other group received lipopolysaccharide in combination with rhAPC 24 μg/ kg/hour from 4 to 24 hours (n = 9). In addition, one group received rhAPC as above as the only intervention (n = 4), and four sham-operated sheep were used for determination of the α and ε isoforms of protein kinase C in pulmonary tissue. Data were assessed by one-way analysis of variance for repeated measurements. Biochemical data were analyzed using Student's t test, or using the Mann–Whitney U test when appropriate. Results: Infusion of endotoxin caused lung injury, manifested by increments in pulmonary artery pressure, in pulmonary microocclusion pressure, in pulmonary vascular downstream resistance, in pulmonary vascular permeability index, in extravascular lung water index and in deterioration of oxygenation that were all attenuated by infusion of rhAPC. Endotoxemia led to changes in inflammation and coagulation, including pulmonary neutrophil accumulation paralleled by increased TNFα and decreased protein C and fibrinogen in animal plasma, which all improved following infusion of rhAPC. Moreover, rhAPC prevented the translocation of protein kinase C α and ε isoforms from the cytosolic fraction of lung tissue extracts. Conclusion: In awake sheep, rhAPC alleviates endotoxininduced lung injury – as characterized by improvements of oxygenation, coagulation and inflammation, as well as by reversal of pulmonary hemodynamic and volumetric changes

Revascularization of the Periodontium After Tooth Grafting in Monkeys

In replanted and homo transplanted teeth a vascular network developed in the blood clot between the two parts of the torn periodontium, which allowed the grafted ligament to regain its vascularity. When dentoalveolar ankylosis developed, the periodontal vasculature was split into a number of vascular clusters. In homotransplants, a definite cellular immunologic response by the host was absent. An acrylic radicular obturator was used.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/67229/2/10.1177_00220345710500025101.pd

A short-term clinical study of marginal bone level change around microthreaded and platform-switched implants

PURPOSE: The marginal bone levels around implants following restoration are used as a reference for evaluating implant success and survival. Two design concepts that can reduce crestal bone resorption are the microthread and platform-switching concepts. The aims of this study were to analyze the placement of microthreaded and platform-switched implants and their short-term survival rate, as well as the level of bone around the implants. METHODS: The subjects of this study were 27 patients (79 implants) undergoing treatment with microthreaded and platform-switched implants between October 2008 and July 2009 in the Dental Hospital of Yonsei University Department of Periodontology. The patients received follow-up care more than 6 months after the final setting of the prosthesis, at which time periapical radiographs were taken. The marginal bone level was measured from the reference point to the lowest observed point of contact between the marginal bone and the fixture. Comparisons were made between radiographs taken at the time of fixture installation and those taken at the follow-up visit. RESULTS: During the study period (average of 11.8 months after fixture installation and 7.4 months after the prosthesis delivery), the short-term survival rate of microthreaded and platform-switched implants was 100% and the marginal bone loss around implants was 0.16±0.08 mm, the latter of which is lower than the previously reported values. CONCLUSIONS: This short-term clinical study has demonstrated the successful survival rates of a microthread and platform-switched implant system, and that this system is associated with reduced marginal bone loss.ope

Effects of Acrylic Restorations on the Periodontium of Monkeys

Replanted teeth that had an acrylic restoration in the middle third of their roots were studied from three days to six months after grafting. The study revealed that the acrylic obturator elicited epithelial proliferation, fibrous encapsulation, moderate chronic inflammation, and adjacent alveolar bone loss.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68162/2/10.1177_00220345720510052201.pd

Visualization and quantification of the oral hygiene effects of brushing, dentifrice use and brush wear using a tooth brushing simulator

Standardized, reproducible brushing regimes were applied to typodonts coated in simulated or biological plaques to assess the effects on tooth cleaning of toothbrush/dentifrice regimens. Replicated typodonts were coated with OccludeTM or GlogermTM indicators to simulate plaque, and brushed reproducibly using a mechanical brushing simulator to compare the cleaning of occlusal surfaces before and after brushing with water or a dentifrice. An in vitro model using salivary inocula to cultivate oral biofilms on typodont surfaces was then developed to evaluate removal of disclosed plaque by new toothbrushes in comparison to toothbrushes with wear equivalent to three months of use. Analyses of typodonts brushed under controlled conditions significantly (p < 0.01) distinguished between brushed and unbrushed surfaces and between the use of water versus dentifrice for the removal of simulated interproximal plaque (p < 0.05). New toothbrushes removed significantly (p < 0.05) more biological plaque from typodont surfaces than brushes that had been worn by repeated brushing. Through controlled and defined brushing of typodonts with simulated and biological plaques, the effectiveness of dental hygiene regimens was compared under reproducible conditions. Data indicate that the cleaning effectiveness of brushing was augmented by the addition of dentifrice and that new brushes were significantly more effective than brushes with substantial wear from previous use