Residual Debris Research Articles

Calculus Removal and Root Surface Roughness When Using the Er:YAG or Er,Cr:YSGG Laser Compared with Conventional Instrumentation Method: A Literature Review.

Objective: The purpose of this literature review was to evaluate the effectiveness of using Er:YAG (erbium-doped yttrium/aluminum/garnet) laser or Er,Cr:YSGG (erbium, chromium-doped yttrium/scandium/gallium/garnet) laser on calculus removal and their effect on the topography and roughness of root surface in comparison with the conventional instruments in the nonsurgical periodontal therapy. Background data: One of the most challenging problems in treatment of periodontal disease is the elimination of plaque and calculus, leaving a clean and smooth root surface to decrease plaque and calculus retention, and for good gingival reattachment. Materials and methods: PubMed and Google Scholar were searched for available literature. The electronic search was limited to articles published in the period between January 2007 and April 2017, in the English language. Results: A total of 47 publications fulfilled the inclusion criteria of this systematic review and screened according to the research questions. Calculus removal using the ultrasonic instrument showed remaining calculus compared with the hand instrument, whereas, on the contrary, erbium lasers revealed no remaining calculus or smaller amounts compared with the conventional instruments when used in appropriate settings. The results of this review showed that ultrasonic instrumentation produced effects on the root surface almost similar to that of hand instrumentation. Er:YAG laser and Er,Cr:YSGG laser clarify a little more surface roughness when compared with conventional instruments. Conclusions: The present systematic review indicates that a combination of scaling and root planing (SRP) using the erbium lasers as an adjunctive therapy at certain parameters can be appropriate to remove residual debris from the root surface and at the same time have little or no negative thermal effect on the root surface. The Er:YAG laser also seems to be the most suitable for nonsurgical periodontal therapy. Additional new good-designed studies are needed to evaluate the effectiveness of erbium lasers with SRP in nonsurgical periodontal therapy.

In vitro effect of XP-Endo finisher on the amount of residual debris and smear layer on the root canal walls

A successful endodontic treatment depends on efficient cleaning and shaping and effective irrigation of root canals. The irrigating solution may not be effective in some areas in the canal. The manufacturer of XP-Endo finisher claims that it can effectively clean the root canals with complex morphology. This study aimed to assess the effect of XP-Endo finisher on the amount of residual debris and smear layer on the root canal walls of mandibular second premolars. In this In vitro study Fifty extracted mandibular second premolars with a root curvature <20° were collected. Root canals were prepared using BioRaCe rotary system. The root canals were in contact with the file and different irrigating solutions for 1 min. The teeth were then randomly divided into four experimental (n = 10) and one positive control group as follows: (1) XPF + saline, (2) XPF + ethylenediaminetetraacetic acid (EDTA), (3) XPF + sodium hypochlorite (NaOCl), (4) XPF + EDTA + NaOCl and (control) EDTA + NaOCl. The teeth were longitudinally sectioned into two halves and the amount of debris and smear layer remaining in the coronal, middle, and apical thirds of the roots was quantified and scored under an electron microscope. The Kruskal-Wallis test was used to compare the groups, and P < 0.05 was considered statistically significant. The highest mean amount of residual debris (2.9 ± 1.13) was noted in XPF + saline group (P < 0.05). XPF + saline and XPF + NaOCl (3.8 ± 0.60) had the lowest efficacy for smear layer removal (P < 0.05) with no significant within-group difference. No significant difference was noted between Groups 2, 3, and 4 with the positive control group regarding debris removal. Groups 2 and 4 had no significant difference with the positive control group regarding smear layer removal. Use of XP-Endo finisher has no superiority to the standard protocol for the use of irrigating solutions (EDTA + NaOCl) for debris and smear layer removal, but in some cases, such as second appointment of regeneration treatment we cannot use NaOCl because of its destructive effects on stem cells; thus, we can benefit from the synergistic effects of XPF and EDTA for better smear layer removal.

Investigation of Post-Fire Debris Flows in Montecito

Debris flows in a burned area, post-fire debris flows, are considered as one of the most dangerous geo-hazards due to their high velocity, long run-out distance, and huge destruction to infrastructures. The rainfall threshold to trigger such hazards is often reduced compared with normal debris flow because ashes generated by mountain fires reduce the permeability of the top soil layer, thus increasing surface runoff. At the same time, burnt material and residual debris have very poor geo-mechanical characteristics, e.g., their internal friction angle and cohesion are typically low, and thus an intense rainfall can easily trigger some debris flows. Studying post-fire debris flow enables us to get a deeper understanding of disaster management. In this paper, the debris flow that occurred in Montecito, California, USA, and was affected by the Thomas Fire was used as a case study. Five major watersheds were extracted based on the digital elevation model (DEM). Remote sensing images were used to analyze the wildfire process, the extent of the burned areas, and the burn severity. The hypsometric integral (HI) and short-duration rainfall records of the watersheds around Montecito when the post-fire debris flows occurred were analyzed. Steep terrain, loose and abundant deposits, and sufficient water supply are the important conditions affecting the formation of debris flows. Taking watersheds as the research objects, HI was used to describe the geomorphic and topographic features, open-access rainfall data was used to represent the water supply, and burn severity represented the abundance of material sources. An occurrence probability model of post-fire debris flow based on HI, short-duration heavy rainfall, and burn severity was developed by using a logistic regression model in post-fire areas. By using this model, the occurrence probability of the post-fire debris flow in different watersheds around Montecito was analyzed based on the precipitation with time. Especially, the change characteristics of occurrence probability of debris flows over time based on the model bring a new perspective to observe the obvious change of the danger of post-fire debris flows and it is very useful for early warning of post-fire debris flows.

Application of the Chinese Aircraft-shaped Sleeve system in the treatment of tibial shaft fractures using a suprapatellar approach for tibial intramedullary nailing: a randomised controlled trial

BackgroundThe use of the suprapatellar approach for intramedullary nailing has recently become popular for the treatment of tibial fractures. This study aimed to investigate the effectiveness of using the Chinese Aircraft-shaped Sleeve (CASS) system on the clinical outcomes of tibial intermedullary nailing using a suprapatellar approach for the treatment of tibial fractures in a cohort of adult Chinese patients.MethodsMagnetic resonance images (MRI) of the knee joints of 212 healthy adults with normal lower limb function from May 2011 to May 2015 were obtained from a level I Chinese regional trauma centre. Sixty inpatients at the same trauma centre who underwent treatment for tibial shaft fractures from June 2015 to June 2018 were enrolled. Tibial intramedullary nailing fixation of tibial shaft fractures via the suprapatellar approach was performed with either a CASS system or a conventional sleeve. The measurements of patellofemoral joint anatomy, the surgical time, the assessments of the patellofemoral joint cartilage conditions, and information of residual debris based on arthroscopic analysis were subsequently collected.ResultsThe mean patellar angle (PA), sulcus angle (SA), sulcus width (SW) and sulcus depth (SD) were 135.40 ± 6.20°, 142.37 ± 5.33°, 33.37 ± 2.73 mm, and 4.29 ± 0.63 mm, respectively. The surgical time until entry reaming commencement and the irrigation time were significantly lower in the CASS group (P < 0.001). The difference in cartilage damage rate between groups was statistically significant (P = 0.031); the difference in residual debris conditions was not statistically significant (P = 0.1967).ConclusionThe use of the CASS system could improve clinical outcomes of intramedullary nailing via suprapatellar approach for patients with a small patellofemoral joint space.

Study on transformation rate of sources to debris flows in meizoseismal area

Since "5.12″ Wenchuan earthquake, a series of debris flows disasters was triggered under precipitation condition, such as "9.26″, "8.14, “7.03” and “7.10” debris flows. In order to study the relationship between the residual sources and debris flows running-outs volume, it was particularly important to study the transformation rate of sources to debris flows, which indicate the eroding degree of sources, and mobilizing into debris flows. According to field reconnaissance of sources and statistical analysis of erosion volume of sources, found out that the transformation rate of sources to debris flows was related to the had occurrences times of debris flows, the drainage area of debris flow gullies, the reserve volume of sources, etc. And the transformation rate of sources has an exponential decay relationship with the occurred times of debris flows. According to error analysis of transformation rate model discovering the error rate ranged from 0 to 0.23%, and according to the verification of transformation rate model, the error value of transformation rate ranged from 0 to 5%.

Influence of size and taper of basic root canal preparation on root canal cleanliness: a scanning electron microscopy study.

To investigate whether a minimally invasive basic root canal preparation technique has an influence on root canal cleanliness in extracted mandibular molar teeth. A total of 80 root canals (40 mesio-buccal and 40 mesio-lingual) from 40 mandibular molars were included. The teeth were divided equally into four different experimental groups depending on the subsequently root canal preparation technique: Group 1: a basic preparation was performed up to size 20, .04 taper; Group 2: a basic preparation was performed up to size 2, .06 taper; Group 3: a basic preparation was performed up to size 25, .04 taper; and Group 4: a basic preparation was performed up to size 25, .06 taper. After the use of each instrument, each root canal was irrigated with 2.5mL of 6% sodium hypochlorite for 30s. Then, 1mL NaOCl was activated for 20s using an EDDY sonic tip. Final irrigation was performed using a total of 5mL of 17% EDTA solution. The roots were then split longitudinally and all root canal thirds were observed through scanning electron microscopy (SEM) to evaluate the presence of superficial debris and smear layer using a scoring system. Data were statistically analysed using the Kruskal-Wallis and Bonferroni tests with a level of significance set at P<0.05. In all groups, there was significantly more residual debris and smear layer in the apical third (P<0.05), with no differences between the middle and coronal thirds (P>0.05). For both the parameters analysed, there was no difference amongst the groups in the middle and coronal thirds (P>0.05), whilst in the apical third significantly less debris and smear layer was found in specimens from groups 3 and 4 than for groups 1 and 2 (P<0.05). All basic root canal preparation techniques were associated with less debris and smear layer on the canal walls in the middle and coronal thirds, without differences among them. Even though debris and smear layer were always present in the apical third, an apical size of 25 resulted in significantly cleaner canals walls compared to a size 20.

Safety evaluation of two α-amylase enzyme preparations derived from Bacillus licheniformis expressing an α-amylase gene from Cytophaga species

A safety assessment was conducted for a symthetic variant Cytophaga sp. α-amylase enzyme expressed in Bacillus licheniformis and formulated into two distinct product formats: whole broth (a preparation in which the production organism is completely inactivated, but containing residual cell debris) and clarified preparation (from which the production organism is completely removed). The enzyme was improved via modern biotechnology techniques for use in the endohydrolysis of starch, glycogen, related polysaccharides and oligosaccharides. Applications range from carbohydrate processing, including the manufacture of sweeteners, fermentation to produce organic acids, amino acids and their salts, and potable or fuel alcohol, with resulting co-products (distillers' grains and corn gluten feed/meal) destined for use in animal feed. The toxicological studies summarized in this article (90-day rodent oral gavage and in vitro genotoxicity studies) noted no test article-related adverse effects and thus substantiate the safety of the α-amylase in not only the clarified form but also as a whole-broth preparation. Consistent with the decision tree analysis for enzymes produced with modern biotechnology techniques, this paper provides supporting information that this variant amylase with homology to an amylase from a potentially pathogenic organism (Cytophaga sp.) can be safely produced in an expression host that belongs to a Safe Strain Lineage, for safe use as processing aid to manufacture human and animal food.

Scanning Electron Microscopy Evaluation of Root Surfaces After Instrumentation With Two Piezoelectric Devices.

Scanning electron microscopy evaluation of root surfaces after ultrasonic instrumentation was performed with 2 different metallic tips on piezoelectric devices. Fresh extracted teeth were collected for experimental observation and randomly divided into 2 groups: Test Group, where the root surfaces were treated using an iron, rough, double nano-structural coated (T-Black), corindone-treated tip, and Control Group where the root surfaces were treated with a conventional iron smooth tip. A scanning electronic microscope analysis was performed and the surface roughness and the amount of residual debris were evaluated. Descriptive and inferential statistics were performed. Twenty specimens were analyzed, 10 per group and a total of 21.4 × 10 μm has been observed. On treated area percentage of debris after ultrasonic scaling in Test Group was 1.9 ± 1.8%, while in Control Group it was 5.7 ± 4.3%. Within the limits of the study, it seems that the efficacy of the novel iron, rough, double nano-structural coated (T-Black), corindone-treated structure tip showed greater performance in terms of root surface debridement than the conventional iron smooth tip. The possibility to use a single tool (ultrasonic device with a specific tip) for the root planing procedure within the nonsurgical mechanical therapy may represent a significant advantage for the clinicians. The tested novel tip seems to be able to show the requested ideal characteristics. However, further clinical studies are needed to demonstrate the in vitro results.

Incidence and Clinical Significance of Positional Downbeat Nystagmus in Posterior Canal Benign Paroxysmal Positional Vertigo.

Background and PurposeThe aim of this study was to determine the incidence and clinical significance of positional downbeat nystagmus (pDBN) after treatment of posterior canal (PC) benign paroxysmal positional vertigo (BPPV).MethodsWe recruited 77 patients with a diagnosis of PC BPPV, and assessed the presence of pDBN during follow-up positional tests after performing the Epley maneuver.ResultsAn immediate response to the Epley maneuver was exhibited by 57 of the 77 patients, with resolution of their positional torsional upbeat nystagmus (pT-UBN). Twenty-two (39%) of them exhibited pDBN during follow-up tests performed 1 hour later. The latency and duration of pDBN were 3.2±2.0 and 12.0±10.0 s (mean±SD), respectively. The maximum slowphase velocity of pDBN was 5.1±2.5 degrees, and ranged from 2.0 to 12.2 degrees. A torsional component was also observed in six patients. The patients with pDBN were much more likely to develop a typical form of PC BPPV again at a 1-week follow-up (5/22, 23%) compared to those without pDBN (1/31, 3%; p=0.036). pDBN disappeared in all patients within 6 months.ConclusionsOur study found transient pDBN in 40% of patients with PC BPPV after the immediate resolution of positional vertigo and pT-UBN. pDBN may be attributed to residual debris in the distal portion of the PC, which can move toward the ampulla producing an ampullopetal flow of endolymph during positioning.

Sa1361 CHOLANGIOSCOPY-GUIDED HOLMIUM LASER LITHOTRIPSY IN THE TREATMENT OF DIFFICULT BILE DUCT STONES- A SINGLE CENTER EXPERIENCE

Using standard techniques, the treatment of bile duct stones is highly effective in 85-90% of cases. In 5-15% the stones are classified as “difficult” due to their size, location, form, calcification or altered anatomy. For these situations alternative treatment options are needed. Cholangioscopy- guided laser- or electrohydraulic lithotripsy increases the success rate of the bile duct stones treatment up to 100%. To evaluate the efficacy, safety and cost- effectiveness of the cholangioscopy guided laser lithotripsy for the treatment of difficult bile duct stones in the context of complications, price and mean procedure time. Data was collected retrospectively from January 2016 to September 2017. All the patients had previous single-session ERCP, sphincterotomy with or without large balloon dilation and plastic stenting performed and bile duct stones were characterized as “difficult” after attempts for extraction using standard techniques or after detection of anatomical abnormalities of the biliary system /strictures/. Patients were scheduled for cholangioscopy with the SpyGlass DS system (Boston Scientific, Marlborough, MA, USA). A 200 μm single use laser fiber (Cook Medical, Bloomington, IN, USA) was positioned close to the stone and lithotripsy was performed until complete fragmentation has been achieved (Settings- 1,2 mJ, 8Hz). The procedure was followed by balloon- or basket extraction of fragments. CBD clearance was confirmed by cholangioscopy. Further interventions were rescheduled if needed. For the period a total of 16 cholangioscopy- guided holmium laser lithotripsies were performed in 14 patients. 2 complications were documented- hemobilia caused discontinuation of the procedure in a patient with essential thrombocitopaenia and a case of mild cholangitis treated with i.v. antibiotic for 5 days. Nasobiliary drainage was left for 24 hours in 2 patients, 2 patients received temporary plastic stents for cholangitis- profilaxis due to residual debris . No serious adverse events requiring surgery, blood transfusions or ICU admission were noted. Cholangioscopy guided Holmium laser lithotripsy is a safe and effective option to treat difficult bile duct stones. The early implementation avoids multiple ERCP- sessions, surgery and related complications in patients, unsuitable for standard endoscopic treatment. Carefull patient selection is needed in relation with the cost- effectiveness and procedure duration.Table 1ResultsNumber of patients14Impacted CBD stones6/14 (42,8%)CBD stones8/14 (57%)Stones in the common hepatic duct2/14 (14,2%)Intrahepatic stones3/14 (21,4%)Stones in the cystic duct1/14 (7,1%)Size of the stones10-35 mmNumber of sessions until complete clearance1,14Duration of the procedure90-180 min.Complications2/14 (14,2%) Open table in a new tab

Sa1366 ENDOSCOPIC PLACEMENT OF A PLASTIC SPIRAL STENT FOR SHORT-TERM BILIARY DRAINAGE IN PATIENTS WITH CHOLELITHIASIS.

There are no guidelines addressing whether a routine drainage should be performed after endoscopic stone extraction in patients with cholelithiasis. However, many endoscopists tend to insert a nasobiliary tube or a biliary stent for prevention of post-ERCP complications. The main concern is that potential residual debris or ampullary edema caused by repeated endoscopic manipulations may disturb normal biliary drainage. Considering the shortcomings of nasobiliary tube and regular stent,we designed a novel plastic spiral stent, which can be expelled in the help of intestinal peristalsis, avoiding repeated duodenoscopy for stent removal, as well as the discomfort caused by nasobiliary catheter. Evaluate the efficacy of a plastic spiral stent for short-term biliary drainage and whether it expelled automatically. : Over a 1-year period, 12 spiral stents were placed for short-term biliary drainage in 12 patients with cholelithiasis who underwent stones extraction by using of endoscopic sphincterotomy, endoscopic papillary balloon dilatation and/or mechanical lithotripsy. No post-ERCP pancreatitis or bleeding occurred, as well as stent related intestinal injuries. All biliary drainages were effective, and all inserted spiral stents were expelled automatically when the patients moved bowels. The median duration from stent placement to expulsion was 4 days (range 2 to 30). Endoscopic placement of a plastic spiral stent for short-term biliary drainage seems a promising therapy in selected patients.Table 1Patient characteristics.Patient numberSexAge, yearsStone numberStone size, cmEndoscopic interventionDuration from stent placement to expulsion, daysHospital stay after stent placement, days1F43Multiple1.6EST+EPBD222M78Single1.0EST+EPBD+ML373F63Multiple1.5EPBD324M60Multiple1.0EST+EPBD435M56Multiple0.9EST+ML436M80Multiple1.2EST+EPBD+ML437F53Multiple1.2EPBD+ML498F79Single0.7EST+ML1149F80Multiple1.4EST+EPBD+ML21*1010M79Multiple1.5EST+EPBD30*811F76Multiple1.6EST+EPBD+ML30*312F74Multiple1.5ML30*3F, female; M, male; EST, endoscopic sphincterotomy; EPBD, endoscopic papillary balloon dilatation; ML, mechanical lithotripsy; *Patient 8-12 did not notice the expelled spiral stents, the absence of which were proved by radiology. Open table in a new tab

Is retained bone debris in cannulated orthopedic instruments sterile after autoclaving?

Cannulated surgical instruments may retain biologic debris after routine cleaning and sterilization. Residual debris after cleaning is assumed to be sterile; however, there is no experimental basis for this assumption. The purpose of this study was to determine the sterility of retained biodebris found within cannulated surgical instruments after autoclave sterilization. Fifteen cannulated drill bits were used to drill pig scapulae to create a plug of bone that was exposed to a mixture of Bacillus cereus, Pseudomonas aeruginosa, and methicillin-resistant Staphylococcus aureus for 60, 120, or 180 minutes prior to sterilization. The drill bits were autoclave sterilized using standard settings. The "sterilized" bone cores were then incubated in solution and streak-plated on blood agar. All 3 positive controls were positive for the experimental bacteria. Two negative controls were positive for contaminant bacteria. A B. cereus strain was recovered from 1 of the experimental group drill bits in the 180-minute group. Pulsed-field gel electrophoresis confirmed that the recovered B. cereus strain was identical to the experimental inoculate. Retained biodebris in cannulated drills may not be sterile after standard autoclave sterilization. In addition, delay of surgical instrument reprocessing may increase the risk of resistant contamination.

Variable responses of non-native and native ants to coarse woody debris removal following forest bioenergy harvests

Timber harvests may facilitate ant invasions of forested landscapes, fostering interactions between non-native and native ants. Harvests that include removal of low-value woody biomass as forest bioenergy feedstock may reduce residual coarse woody debris, thereby altering food and cover resources for ant species. We manipulated: (1) volume and distribution of coarse woody debris in stand-scale treatments ranging from intensive coarse woody debris removal to no coarse woody debris removal; and (2) coarse woody debris availability at microsite locations within stand-scale treatments, including piles of hardwood stems, piles of conifer stems, and no pile locations in North Carolina, USA and windrows (i.e., long, linear piles of harvest residues) and no windrows in Georgia, USA, in recently clearcut pine plantations (n = 4 per state). We captured ants in regenerating stands and tested treatment- and location-level effects on non-native and native ant relative abundances. Invasive ants represented 19% of ant taxa richness, but comprised 94% of total ant captures. Red imported fire ant (Solenopsis invicta Buren, hereafter “RIFA”) dominated the ant community in young plantations. RIFA avoided windrows, but its relative abundance did not differ among stand-scale treatments. Coarse woody debris retention in stand-scale treatments and at microsite locations favored non-RIFA ants, including Asian needle ant (Brachyponera chinensis Emery) and several native ant species. Dual invasions of RIFA and Asian needle ant in young plantations of the eastern United States may commonly occur because the two species may not compete for resources on the forest floor. Reduction of coarse woody debris via intensified woody biomass harvesting may negatively affect non-RIFA ant species and promote RIFA colonization, thereby indirectly increasing deleterious effects of RIFA on other wildlife.

Micromachining of optical fiber its fabrication technologies of liquid-assisted femtosecond laser

ABSTRACTFemtosecond (fs) laser has the advantages of good beam quality and high precision, which is one of the best methods for processing optical fiber mini-sensors, but residual debris on the surface of the machined fiber structure will affect the sensor performance. In this paper, the laser parameters of laser pulses and translation speed were investigated for the quality of fiber micro-cavities contrast in the air and the water, it was proved the effectiveness of using liquid-assisted to improve the quality of laser micromachining.

Histopathological evaluation of aortic coarctation after conventional balloon angioplasty in neonates.

Optimal management strategy for native aortic coarctation in neonates and young infants is still a matter of debate. The surgical procedure, histopathologic research, and clinical outcome in 15 neonates who underwent surgery after successful balloon angioplasty is the basis of this study. Between 01 October, 2014 and 01 August, 2017, we enrolled 15 patients with native aortic coarctation for this study. These patients had complications regarding recoarctation, following balloon angioplasty intervention at our institute and other centres. Surgically extracted parts were examined histopathologically and patient's data were collected retrospectively.ResultThe reasons for recurrence of recoarctation after balloon angioplasty are as follows: patients with higher preoperative echocardiographic gradients had recoarctation earlier, neointimal proliferation, aortic intimal fibrosis at the region of ductal insertion, and ductal residual tissue debris after balloon angioplasty. No repeat intervention was required in the 15 patients who underwent surgery followed by balloon angioplasty. Early mortality was seen in one patient after surgery. Postoperative complication in the surgical group occurred in the form of chylothorax in one patient. In centres in which the neonatal ICU is inexperienced, balloon angioplasty is particularly recommended. In developing neonatal clinics, balloon angioplasty, when performed on patients at their earliest possible age, delays actual corrective operation to a later date, which in turn provides less risky surgical outcomes in infants who are gaining weight, growing, and do not have any haemodynamic complaints.

Evaluation of Effectiveness of Two Different Endodontic Retreatment Systems in Removal of Gutta-percha: Anin vitroStudy

To determine the effectiveness of two different endodontic retreatment systems for the removal of laterally compacted gutta-percha (GP). Sixty-three freshly extracted human maxillary central incisors were used for the study. The teeth were instrumented with K-flex files and obturated using lateral condensation technique with GP and AH Plus sealer. The teeth were divided into three retreatment groups, each group consisting of 21 teeth. Group I: D-RaCe desobturation files (D-RaCe); group II: ProTaper Universal retreatment files (PTUR); group III: Hedstrom files (H-file). After removal of GP, the teeth were split longitudinally and divided into three equal parts: Cervical, middle, and apical third. The middle and apical thirds of all root halves were examined using scanning electron microscope (SEM). The total surface area covered by the residual debris was evaluated using Motic Image plus 2.0 software. Statistical analysis was done by one-way analysis of variance (ANOVA) test with a p-value <0.05 used to determine significance and Tukey's multiple post hoc tests used for comparison between the groups, and 't' test was done for comparison between the thirds within the same group. The PTUR retreatment files showed overall better performance compared with D-RaCe files and H-files. The PTUR files performed better at middle third compared with others. The PTUR files and D-RaCe files performed equally at apical third better than H-files. ProTaper retreatment files are better compared with D-RaCe files and H-files for the retreatment of the previously endodontically treated teeth. Highest efficacy for the removal of GP was shown by ProTaper Universal System followed by D-RaCe and H-file.

Retreatability of root canals filled with Gutta percha and a novel bioceramic sealer: A scanning electron microscopy study.

Aim:This study aimed to evaluate the residual filling material and the reestablishment of working length (WL) and apical patency after retreatment of BioRoot™ RCS, versus TotalFill® BC Sealer, and AH26, used in a single cone obturation technique.Materials and Methods:Sixty single-rooted permanent canines were instrumented up to size 40/.04 (Sendoline, Täby, Sweden). The samples were filled with GP/AH26 (Group 1), GP/TotalFill BC Sealer (Group 2), and GP/BioRoot RCS (Group 3). Eight teeth were used in the positive and negative control groups. Canals were retreated using the Protaper Universal retreatment files (Dentsply Maillefer, Ballaigues, Switzerland) and further instrumented up to size 50/.04 (Sendoline, Täby, Sweden). The ability to reestablish WL and apical patency was recorded. Furthermore, the samples were observed under a scanning electron microscope, in order to evaluate the residual filling material. Data were analyzed statistically with the Fisher's exact and the Kruskal–Wallis tests (P < 0.05).Results:There was no statistically significant difference in the WL and patency recovery among the groups. Neither the intragroup comparison among canal thirds nor the intergroup comparison in each canal third or in total canal area revealed any significant differences in the percentage of the remaining filling material after retreatment.Conclusion:Residual material debris was observed in all samples regardless of the sealer used. All the sealers were removed to a similar extent. The WL and patency were reestablished sufficiently in all groups.

Simulated-Use Polytetrafluorethylene Biofilm Model: Repeated Rounds of Complete Reprocessing Lead to Accumulation of Organic Debris and Viable Bacteria.

OBJECTIVE Biofilm has been implicated in bacterial persistence and survival after endoscope reprocessing. In this study, we assessed the impact of different methods of reprocessing on organic residues and viable bacteria after repeated rounds of biofilm formation when each was followed by full reprocessing. METHODS ATS-2015, an artificial test soil containing 5-8 Log10 colony-forming units (CFU) of Enterococcus faecalis and Pseudomonas aeruginosa, was used to form biofilm in polytetrafluroethylene channels overnight on 5 successive days. Each successive day, full pump-assisted cleaning using bristle brushes or pull-through devices in combination with enzymatic or nonenzymatic detergents followed by fully automated endoscope reprocessor disinfection using peracetic acid was performed. Residuals were visualized by scanning electron microscopy (SEM). Destructive testing was used to assess expected cutoffs for adenosine triphosphate (ATP; <200 relative light units), protein (<2 µg/cm2), and viable bacteria count (0 CFU). RESULTS Protein residuals were above 2 µg/cm2, but ATP residuals were <200 relative light units for all methods tested. Only when enzymatic cleaner was used for cleaning were there no viable bacteria detected after disinfection irrespective of whether bristle brushes or pull-through devices were used. SEM revealed that some residual debris remained after all reprocessing methods, but more residuals were detected when a nonenzymatic detergent was used. CONCLUSIONS Surviving E. faecalis and P. aeruginosa were only detected when the non-enzymatic detergent was used, emphasizing the importance of the detergent used for endoscope channel reprocessing. Preventing biofilm formation is critical because not all current reprocessing methods can reliably eliminate viable bacteria within the biofilm matrix. Infect Control Hosp Epidemiol 2017;38:1284-1290.

Green emission fluorophores in eyes with atrophic age-related macular degeneration: a colour fundus autofluorescence pilot study

Background/AimsTo investigate the presence of short-wave fluorophores within regions of age-related macular degeneration (AMD)-associated macular atrophy (MA) area.MethodsThis is a prospective, observational, cross-sectional case series. 25 eyes (18 patients) with...

Antimicrobial Efficacy of Contact Lens Care Solutions Against Neutrophil-Enhanced Bacterial Biofilms.

PurposeNeutrophil-derived extracellular debris has been shown to accelerate bacterial biofilm formation on hydrogel and silicone hydrogel contact lens surfaces compared to lenses inoculated with bacteria alone. The purpose of this study was to evaluate the disinfection efficacy of four standard commercial contact lens cleaning regimens against neutrophil-enhanced bacterial biofilms formed on silicone hydrogel contact lenses.MethodsFour reference strains were used: Pseudomonas aeruginosa, Serratia marcescens, Stenotrophomonas maltophilia, and Staphylococcus aureus. Human neutrophils were isolated from peripheral blood by venipuncture. Unworn Lotrafilcon B lenses were incubated overnight in each respective strain with stimulated neutrophils. Contact lenses were then cleaned using one of four contact lens care solutions according to manufacturer instructions. Bacterial viability was assessed by colony counts and confocal microscopy. Volume of residual debris on lens surfaces after cleaning was quantified using IMARIS software.ResultsAll four solutions tested showed effective antimicrobial activity against each bacterial strain; however, substantial amounts of nonviable bacteria and cellular debris remained on the lens surface despite concomitant digital cleaning.ConclusionsNecrotic cellular debris that accumulates under the posterior lens surface during wear of an inoculated contact lens is not fully removed during routine cleaning and disinfection.Translational RelevanceThe accumulation of residual cellular debris on the contact lens surface may contribute to new colonization of the lens and represents a significant risk factor for a contact lens–related adverse event. Additional studies are needed to correlate these findings with risk for corneal infiltrative and/or infectious events in a standard animal model.