Biomedical subjects

E Schäfer

Publications and source records attributed to E Schäfer.

At least 19 recordsLinked to original sources

PubMed2007

[Tonsillectomy technique: bipolar scissors vs raspatory: results of a case control study in 138 patients].

BACKGROUND: Postoperative bleeding is the major complication in tonsillectomy, and pain the most common side effect. The use of bipolar scissors versus blunt dissection tonsillectomy were compared in this study in order to evaluate postoperative bleeding and pain, as well as operative time. METHODS: In this case control study, 138 patients with the diagnosis of chronic tonsillitis, mononucleosis or a peritonsillar abscess were divided into two groups. A total of 78 patients were operated using bipolar scissors while 60 patients underwent tonsillectomy by blunt dissection. Operating time, frequency of postoperative bleeding and the postoperative pain score were compared between these two groups. RESULTS: The average operating time in the bipolar scissor group showed a tendency to be shorter than in the blunt dissection group (mean 4.1 min), although this did not reach a level of statistical significance. No differences were seen in pain scores or in the incidence of postoperative bleeding. CONCLUSION: The data documented in this study show that tonsillectomy with bipolar scissors might represent a surgical option to reduce surgical time in a larger patient group. Postoperative pain and the incidence of postoperative bleeding did not show any statistical difference between the two surgical techniques.

Adolescent↗

PubMed2006

[Risk management--a new aspect of quality assessment in intensive care medicine: first results of an analysis of the DIVI's interdisciplinary quality assessment research group].

Patient security has become one of the major aspects of clinical management in recent years. The crucial point in research was focused on malpractice. In contradiction to the economic process in non medical fields, the analysis of errors during the in-patient treatment time was neglected. Patient risk management can be defined as a structured procedure in a clinical unit with the aim to reduce harmful events. A risk point model was created based on a Delphi process and founded on the DIVI data register. The risk point model was evaluated in clinically working ICU departments participating in the register data base. The results of the risk point evaluation will be integrated in the next data base update. This might be a step to improve the reliability of the register to measure quality assessment in the ICU.

Critical Care↗

PubMed2006

Comparative study on the shaping ability and cleaning efficiency of rotary Mtwo instruments. Part 1. Shaping ability in simulated curved canals.

AIM: To compare the shaping ability of Mtwo instruments with K3 and RaCe instruments. Part 1 of this two-part report describes the efficacy of these nickel-titanium instruments in simulated curved root canals. METHODOLOGY: Simulated canals with 28 degree and 35 degree curves in resin blocks were prepared with Mtwo instruments using a single length technique and with K3 and RaCe instruments using a crowndown preparation technique (n = 20 canals in each case). Pre- and post-instrumentation images were recorded and assessment of canal shape was completed with a computer image analysis program. Material removal was measured at 20 measuring points, beginning 1 mm from the endpoint of preparation. Incidence of canal aberrations, preparation time, changes of working length and instrument failures were also recorded. The data were analysed statistically using ANOVA and Student-Newman-Keuls test. RESULTS: On an average, canals prepared with Mtwo instruments remained better centred compared with those enlarged with K3 or RaCe instruments. Six RaCe instruments, four K3 files and none of the Mtwo instruments fractured during preparation (P > 0.05). In both of the canal types, Mtwo was significantly faster (P < 0.001). It was possible with all types of instruments to control working length as well. CONCLUSIONS: Mtwo instruments prepared curved canals rapidly, respected original canal curvature well and were safe to use.

Analysis of Variance↗

PubMed2006

Comparative study on the shaping ability and cleaning efficiency of rotary Mtwo instruments. Part 2. Cleaning effectiveness and shaping ability in severely curved root canals of extracted teeth.

AIM: To compare the cleaning effectiveness and shaping ability of Mtwo, K3, and RaCe nickel-titanium rotary instruments during the preparation of curved root canals in extracted human teeth. METHODOLOGY: A total of 60 root canals of mandibular and maxillary molars with curvatures ranging between 25 degrees and 35 degrees were divided into three groups of 20 canals. Based on radiographs taken prior to instrumentation with the initial instrument inserted into the canal, the groups were balanced with respect to the angle and the radius of canal curvature. Canals were prepared using a low-torque control motor. Using pre- and post-instrumentation radiographs, straightening of the canal curvatures was determined with a computer image analysis program. The amount of debris and smear layer was quantified on the basis of a numerical evaluation scale. The data established for scoring the debris and the smear layer was separately recorded and analysed statistically using the Kruskal-Wallis test. RESULTS: During preparation no instrument separated. Completely clean root canals were never observed. For debris removal Mtwo instruments achieved significantly better results (P < 0.001) than K3 and RaCe instruments. The results for remaining smear layer were similar and not significantly different (P > 0.05). Mtwo instruments maintained the original canal curvature significantly better (P < 0.05) than the other instruments. Instrumentation with Mtwo files was significantly faster than with K3 or RaCe instruments (P < 0.05). CONCLUSIONS: Under the conditions of this study, Mtwo instruments resulted in good cleaning and maintained the original curvature significantly better than K3 or RaCe files.

Analysis of Variance↗

PubMed2006

A comparative study of selected properties of ProRoot mineral trioxide aggregate and two Portland cements.

AIM: To compare solubility, microhardness and radiopacity of ProRoot mineral trioxide aggregate (MTA) with two Portland cements (PC: CEM I and CEM II). METHODOLOGY: Solubility: for standardized samples (n = 12/group) ring moulds were filled with the cements. These samples were immersed in double-distilled water for 1 min, 10 min, 1 h, 24 h, 72 h, and 28 days. Mean loss of weight was determined. Microhardness: five samples of each cement were produced. All samples were loaded with a diamond indenter point with a weight of 100 g for 30 s. Radiopacity: five samples per cement were produced. These samples were tested according to the ISO standards to compare their radiodensity to that of an aluminium step wedge (1-9 mm). Differences between the three materials with respect to their solubility, microhardness and radiopacity were analysed using ANOVA and Student-Newman-Keuls. RESULTS: After 28 days MTA was of low solubility (0.78%) compared with CEM I (31.38%) and CEM II (33.33%). At exposure times >1 min the two PCs were significantly more soluble than MTA (P < 0.05). The microhardness for MTA was significantly higher (39.99 HV; P < 0.001) compared with the two PC (CEM I: 16.32 HV; CEM II: 13.51 HV). MTA was significantly more radiopaque (5.34 mm Al) than CEM I (3.32 mm Al) and CEM II (2.52 mm Al) (P < 0.05), whereas CEM I was significantly more radiopaque than CEM II (P < 0.05). CONCLUSIONS: Mineral trioxide aggregate displayed superior material properties than both Portland cements.

Aluminum Compounds↗

PubMed2006

The influence of various automated devices on the shaping ability of Mtwo rotary nickel-titanium instruments.

AIM: To compare the shaping ability of Mtwo rotary nickel-titanium instruments in simulated curved canals and in curved canals of extracted teeth when set into permanent rotation with two different torque-limited automated devices. METHODOLOGY: Root canal instrumentation was performed with two different torque-limited automated devices (Mtwo direct handpiece and Endo IT motor) using Mtwo rotary nickel-titanium instruments up to size 35. Simulated canals: 28 degrees and 35 degrees curved canals in resin blocks (n = 20 canals in each group) were prepared. Pre- and post-instrumentation images were recorded and assessment of canal shape was completed with a computer image analysis program. Extracted teeth: a total of 40 curved root canals were divided into two groups, which were balanced with respect to the angle and the radius of canal curvature. Straightening of the canal curvatures was determined with a computer image analysis program. Incidence of canal aberrations, preparation time, changes of working length and instrument failures were recorded both in simulated and real canals and were analysed using the t-test and a chi-square test. RESULTS: In simulated canals, instrumentation with Endo IT was significantly faster than with Mtwo direct (P < 0.05). No significant differences between the two devices were noted when all other parameters were assessed (P > 0.05). Only one instrument separated (Mtwo direct) during the enlargement of 28 degrees curved simulated canals. All systems maintained working distance well. CONCLUSIONS: Both systems respected original root canal curvature well and were safe, indicating that the Mtwo direct handpiece is suitable for preparing curved root canals with the Mtwo instruments.

Chi-Square Distribution↗

PubMed2006

Multiple giant leiomyomas of the esophagus and stomach.

Leiomyomas are rare esophageal disorders, although among the benign esophageal neoplasms, they are the most common. Multiple leiomyomas are distinguished from esophageal leiomyomatosis, an extremely rare condition, which is associated with Alport syndrome, showing deletions and rearrangements of the COL4A5/COL4A6 gene. There are only a few reports of diffuse multilocular lesions. A 19-year-old man presented with upper gastrointestinal bleeding and diffuse abdominal pain. On endoscopy multiple nodules covered with intact mucosa were present, the largest tumor arising from the gastro-esophageal border infiltrating the cardia. Barium swallow demonstrated narrowing of the middle and lower esophagus with the upper third of the stomach filled by the tumor. Thorax and abdominal CT scans revealed infiltration of almost the total aboral esophagus by the tumor with compression of left and right bronchi. The infiltration reached the whole lesser curvature of the stomach. Endosonography showed multiple encapsulated nodules. Due to the extended tumor growth with infiltration of the upper third of the stomach, a total esophago-gastrectomy with reconstruction by colon interposition was performed. On histopathological examination multiple esophageal leiomyomas with infiltration of the proximal third of the stomach was shown. Immunohistochemically the tumor stained positive for desmin and sm-actin and negative for CD34 and c-kit. Genetic analysis ruled out a deletion of the COL4A5/COL4A6 locus on chromosome X that is linked with Alport syndrome-diffuse leiomyomatosis. Extended mutations in the COL4A5 gene, associated with Alport syndrome, to the COL4A6 gene, are required for the development of leiomyomatosis. In young patients with diffuse multinodular infiltration by encapsulated tumors, esophageal leiomyomatosis should be considered. If the proximal third of the stomach is infiltrated by the tumor an extended resection is necessary. Reconstruction procedures include colon interposition.

Adult↗

PubMed2006

Reaction of rat pulp tissue to Carisolv 'new gel'--a histocytological evaluation.

BACKGROUND: This study was an histological examination of pulp tissue exposed to Carisolv 'new gel' after 1 to 28 days. METHODS: An occlusal cavity was prepared in 64 caries-free molar teeth of 16 Wistar rats. The roofs of the pulp chambers were perforated and Carisolv 'new gel' solution was placed onto the exposed pulps of 32 molar teeth for 20 minutes. Thirty-two contralateral molar teeth served as controls and were coated with an inert liquid containing isotonic saline solution and carmellose for 20 minutes as well. The pulps of all teeth were capped with Ca(OH)2 and the cavities were filled with a flowable composite in combination with a self-etching dentine adhesive. The animals were sacrificed after 1, 3, 7 and 28 days. Eight teeth per group and the time period were histologically examined, scored, and statistically evaluated (Wilcoxon-test). RESULTS: The results showed no statistically significant differences between the Carisolv group and the control group (p > 0.05). The observed pulp reaction was essentially the same as those reported in the past being typical for the effect of calcium hydroxide as a direct pulp capping agent. CONCLUSION: Compared to Ca(OH)2, Carisolv 'new gel' did not cause any different or additional pulp reaction in healthy teeth.

Animals↗

PubMed2005

Influence of different types of automated devices on the shaping ability of rotary nickel-titanium FlexMaster instruments.

AIM: To compare the shaping ability of rotary FlexMaster nickel-titanium instruments in simulated curved canals and in curved canals of extracted teeth when set into permanent rotation with three different torque-limited automated devices. METHODOLOGY: Root canal instrumentation was performed with three different torque-limited automated devices (ENDOadvance, SIRONiTi and Endo IT motor) by FlexMaster nickel-titanium instruments up to size 35. Simulated canals: 28 degree and 35 degree curved canals in resin blocks (n = 20 canals in each group) were prepared. Pre- and post-instrumentation images were recorded and assessment of canal shape was completed with a computer image analysis program. Extracted teeth: A total of 60 curved root canals were divided into three groups, which were balanced with respect to the angle and the radius of canal curvature. Straightening of the canal curvatures was determined with a computer image analysis program. Incidence of canal aberrations, preparation time, changes of working length and instrument failures were recorded both in simulated and real canals. RESULTS: In simulated and real canals, instrumentation with Endo IT was significantly faster than with SIRONiTi (P < 0.05). With respect to canal aberrations in simulated canals, there were no significant differences between the devices (P > 0.05), even though more aberrations were created with ENDOadvance and SIRONiTi. In real canals, the Endo IT motor resulted in significantly less straightening during instrumentation (P < 0.05) than SIRONiTi. A total of three instruments separated (one file in each group) during the enlargement of 35 degree curved simulated canals. All systems maintained working distance well. CONCLUSIONS: All systems respected original root canal curvature well and were safe, indicating that torque-limited rotation handpieces are suitable for preparing curved root canals.

Dental Alloys↗

PubMed2004

Comparative investigation of two rotary nickel-titanium instruments: ProTaper versus RaCe. Part 2. Cleaning effectiveness and shaping ability in severely curved root canals of extracted teeth.

AIM: To determine the cleaning effectiveness and shaping ability of ProTaper and RaCe nickel-titanium rotary instruments during the preparation of curved root canals in extracted human teeth. METHODOLOGY: A total of 48 root canals of mandibular and maxillary molars with curvatures ranging between 25 degrees and 35 degrees were divided into two groups of 24 canals each. Based on radiographs taken prior to instrumentation with the initial instrument inserted into the canal, the groups were balanced with respect to the angle and the radius of canal curvature. Canals were prepared using a crown-down preparation technique. After each instrument, the root canals were flushed with a 2.5% NaOCl solution and at the end of instrumentation with NaCl. Using pre- and post-instrumentation radiographs, straightening of the canal curvatures was determined with a computer image analysis program. After splitting the roots longitudinally, the amount of debris and smear layer was quantified on the basis of a numerical evaluation scale, using a scanning electron microscope (SEM). The data established for scoring the debris and the smear layer were separately recorded and analysed statistically using the Wilcoxon test. RESULTS: Two ProTaper and three RaCe instruments fractured; there was no significant difference between instrument types (P > 0.05). Completely clean root canals were never observed. For debris removal, RaCe files achieved significantly better results (P < 0.001) than ProTaper instruments. The results for remaining smear layer were similar and not significantly different (P > 0.05). RaCe instruments maintained the original canal curvature significantly better (P < 0.05) than ProTaper instruments. No significant differences were detected between the instruments (P > 0.05) for the time taken to prepare the canals. CONCLUSIONS: Under the conditions of this study, RaCe instruments resulted in relatively good cleaning and maintained the original curvature significantly better than ProTaper did.

Chelating Agents↗

PubMed2004

Comparative investigation of two rotary nickel-titanium instruments: ProTaper versus RaCe. Part 1. Shaping ability in simulated curved canals.

AIM: To compare the shaping ability of ProTaper with Reamer with Alternating Cutting Edges (RaCe) instruments. Part 1 of this two-part report describes the efficacy of these two nickel-titanium instruments in simulated curved root canals. METHODOLOGY: Simulated canals with 28 degrees and 35 degrees curves in resin blocks were prepared with ProTaper and RaCe instruments using a crown-down preparation technique (n = 24 canals in each case). Pre- and postinstrumentation images were recorded, and assessment of canal shape was completed with a computer image analysis program. Material removal was measured at 20 measuring points, beginning 1 mm from the apex. Incidence of canal aberrations, preparation time, changes of working length and instrument failures were also recorded. The data were analysed statistically using the Mann-Whitney U-test or the chi-square test. RESULTS: On average, canals prepared with RaCe instruments remained better centred compared with those enlarged with ProTaper files. Three RaCe instruments and two ProTaper files fractured during preparation (P > 0.05). Between both the canal types, RaCe was significantly faster (P < 0.001) than ProTaper and maintained working length significantly better (P < 0.05). CONCLUSION: Both instruments prepared curved canals rapidly and were relatively safe. RaCe respected original canal curvature better than ProTaper, which tended to transport towards the outer aspect of the curve.

Chi-Square Distribution↗

PubMed2003

Efficiency of rotary nickel-titanium K3 instruments compared with stainless steel hand K-Flexofile. Part 1. Shaping ability in simulated curved canals.

AIM: To compare the shaping ability of K3 rotary nickel-titanium instruments with stainless steel K-Flexofiles manipulated by hand. Part 1 of this two-part report describes the efficiency of these two instruments in simulated curved root canals. METHODOLOGY: Simulated canals with 28 degrees and 35 degrees curves in resin blocks were prepared by K3 instruments with a rotational speed of 250 r.p.m. using a crown-down preparation technique, or by K-Flexofiles using a reaming motion -i = 24 canals in each case). All canals were prepared up to size 35 at the end-point of preparation. Pre- and postinstrumentation images were recorded, and assessment of canal shape was completed with a computer image analysis program. Material removal was measured at 20 measuring points, beginning 1 mm from the apex. Incidence of canal aberrations, preparation time, changes of working length and instrument failures were also recorded. RESULTS: In comparison with stainless steel K-Flexofiles, rotary K3 instruments achieved better canal geometry and showed significantly less canal transportation (P < 0.05) Eleven K3 instruments and none of the K-Flexofiles fractured during preparation (P < 0.05). Between both the canal types, K3 was significantly faster (P < 0.001) than K-Flexofiles. Both instruments maintained a good working distance. CONCLUSIONS: K3 instruments prepared curved canals rapidly and with minimal transportation towards the outer aspect of the curve. Fractures occurred significantly more often with K3.

Acrylic Resins↗

PubMed2003

Efficiency of rotary nickel-titanium K3 instruments compared with stainless steel hand K-Flexofile. Part 2. Cleaning effectiveness and shaping ability in severely curved root canals of extracted teeth.

AIM: To determine the cleaning effectiveness and the shaping ability of K3 nickel-titanium rotary instruments and stainless steel hand K-Flexofiles during the preparation of curved root canals in extracted human teeth. METHODOLOGY: A total of 60 root canals of mandibular and maxillary molars with curvatures ranging between 25 degrees and 35 degrees were divided into two groups of 30 canals. Based on radiographs taken prior to instrumentation with the initial instrument inserted into the canal, the groups were balanced with respect to the angle and the radius of canal curvature. Canals were prepared by K3 instruments using a crown-down preparation technique or by K-Flexofiles using a reaming motion up to size 35. After each instrument, the root canals were flushed with 5 mL of a 2.5% NaOCl solution and at the end of instrumentation with 5 mL of saline. Using pre- and post-instrumentation radiographs, straightening of the canal curvatures was determined with a computer image analysis program. After splitting the roots longitudinally, the amount of debris and smear layer were quantified on the basis of a numerical evaluation scale, using a scanning electron microscope. The data established for scoring the debris and the smear layer were separately recorded and analysed statistically using the Wilcox-on's test. RESULTS: None of the stainless steel K-Flexofiles but 5 K3 nickel-titanium instruments separated. Completely clean root canals were never observed. For debris removal, K-Flexofiles achieved significantly better results (P < 0.001) than K3 instruments. The results for remaining smear layer were similar (P > 0.05). K3 instruments maintained the original canal curvature significantly better (P < 0.0001) than K-Flexofiles. No significant differences were detected between the instruments (P > 0.05) for the time taken to prepare the canals. CONCLUSIONS: Under the conditions of this study, K-Flexofiles allowed significantly better removal of debris than K3 instruments. K3 files maintained the original curvature significantly better. A number of K3 instruments fractured.

Dental Alloys↗

PubMed2003

Solubility of root-canal sealers in water and artificial saliva.

AIM: To compare the weight loss of eight different root-canal sealers in water and in artificial saliva with different pH values. METHODOLOGY: For standardized samples (n = 12 per group), ring moulds were filled with epoxy resin (AH 26, AH Plus)-, silicone (RSA RoekoSeal)-, calcium hydroxide (Apexit, Sealapex)-, zinc oxide-eugenol (Aptal-Harz)-, glass-ionomer (Ketac Endo)- and polyketone (Diaket)-based sealers. These samples were immersed in double-distilled water or artificial saliva with different pH values (7.0, 5.7 and 4.5) for 30 s, 1 min, 2 min, 5 min, 10 min, 20 min, 1 h, 2 h, 10 h, 24 h, 48 h, 72 h, 14 days and 28 days. Mean loss of weight was determined and analysed statistically using a one-way anova and Student-Newman-Keuls test for all pairwise comparisons. RESULTS: Most sealers were of low solubility, although Sealapex, Aptal-Harz and Ketac Endo showed a marked weight loss in all liquids. Even after 28 days of storage in water, AH 26, AH Plus, RSA RoekoSeal, and Diaket showed less than 3% weight loss. At exposure times greater than 14 days, Sealapex showed the significantly greatest weight loss of all sealers tested (P < 0.05). Aptal-Harz and Ketac Endo were significantly more soluble in saliva (pH 4.5) than in water (P < 0.05). CONCLUSIONS: Under the conditions of the present study, AH Plus showed the least weight loss of all sealers tested, independent of the solubility medium used. Sealapex, Aptal-Harz and Ketac Endo had a marked weight loss in all liquids.

Analysis of Variance↗

PubMed2002

Efficiency of rotary nickel-titanium FlexMaster instruments compared with stainless steel hand K-Flexofile--Part 1. Shaping ability in simulated curved canals.

AIM: The purpose of this study was to compare the shaping ability of FlexMaster rotary nickel-titanium instruments with stainless steel hand K-Flexofiles. This part of the two-part report describes the efficiency of these two instruments in simulated curved root canals. METHODOLOGY: Simulated 28 degree- and 35 degree-curved canals were prepared by the FlexMaster instruments with a rotational speed of 250 rpm using a crown-down preparation technique. and by the K-Flexofiles using a reaming motion (n = 24 canals in each case). All canals were prepared up to size 35. The pre- and post-instrumentation images were recorded and assessment of the canal shape was completed with a computer image analysis program. The material removal was measured at 20 measuring points, beginning 1 mm away from the apex. Incidence of canal aberrations, preparation time,changes of working length and instrument failures were also recorded. RESULTS: In comparison with stainless steel K-Flexofiles, the rotary FlexMaster instruments achieved bet-ter canal geometry, showed less canal transportation and created fewer canal aberrations in both the canal types. Two FlexMaster instruments were separated, and 15 FlexMaster instruments and 11 K-Flexofiles were permanently deformed during preparation. However, these differences were not significant (P > 0.05). Between both the canal types, FlexMaster was significantly faster (P < 0.001) than K-Flexofiles. Both instruments maintained a good working distance. CONCLUSIONS: FlexMaster instruments prepared curved canals rapidly, and with minimal transportation towards the outer aspect of the curve.

Dental Instruments↗

PubMed2002

Efficiency of rotary nickel-titanium FlexMaster instruments compared with stainless steel hand K-Flexofile--Part 2. Cleaning effectiveness and instrumentation results in severely curved root canals of extracted teeth.

AIM: To determine the cleaning effectiveness and the shaping ability of FlexMaster nickel-titanium rotary instruments and stainless steel hand K-Flexofiles during the preparation of curved root canals in extracted human teeth. METHODOLOGY: A total of 48 root canals with curvatures ranging between 25 degrees and 35 degrees were divided into two groups of 24 canals. Based on radiographs taken prior to the instrumentation with the initial instrument inserted into the canal, the groups were balanced with respect to the angle and the radius of canal curvature. Canals were prepared by FlexMaster instruments using a crown-down preparation technique or by K-Flexofiles using a reaming working motion up to size 35. After each instrument, the root canals were flushed with 5 mL of a 2.5% NaOCl solution and at the end of instrumentation with 5 mL of NaCl. Using the pre- and post-instrumentation radiographs, straightening of the canal curvatures was determined with a computer image analysis program. After splitting the roots longitudinally, the amount of debris and smear layer were quantified on the basis of a numerical evaluation scale, using a scanning electron microscope. RESULTS: Completely cleaned root canals were not found with any of the two instruments. In general, K-Flexofiles resulted in significantly less debris(P < 0.001) and less smear layer (P < 0.05) than Flex-Master instruments, but these differences were not significant in the apical third of the canals (P > 0.05). FlexMaster instruments maintained the original canal curvature significantly better (P < 0.0001) than K-Flexofiles. No significant differences were detected between the instruments (P > 0.05) for the time taken to prepare the canals. CONCLUSIONS: Under the conditions of this study, K-Flexofiles allowed significantly better canal cleaning than FlexMaster instruments. FlexMaster instruments maintained the original curvature significantly better.

Dental Instruments↗

PubMed2002

Effect of sterilization on the cutting efficiency of PVD-coated nickel-titanium endodontic instruments.

AIM: To investigate alterations in cutting efficiency when conventional and titanium nitride (TiN) coated nickel-titanium (NiTi) K-files were exposed to repeated sterilization using an autoclave. METHODOLOGY: A total of 96 NiTi K-files (size 35) were randomly divided into two groups (A and B) of 48 instruments each. Whilst the instruments of group B were exposed to physical vapour deposition (PVD) creating a coating of a TiN layer, the files of group A were not coated. The instruments of groups A and B were randomly divided into four subgroups of 12 instruments each. A.1/B.1: Instruments were exposed to five cycles of sterilization. A.2/B.2: Instruments were exposed to 10 cycles of sterilization. A.3/B.3: Instruments were immersed in NaOCl for 30 min, rinsed in water, and exposed to five cycles of sterilization. A.C/B.C: Instruments were not sterilized (controls). The cutting efficiency of all files was determined by means of a computer-driven testing device. Special plastic samples with cylindrical canals were used and the maximum penetration depth of the files into the lumen was assessed. RESULTS: The TiN-coated instruments of groups B.1, B.2 and B.3 showed no significant difference in comparison with the penetration depths of the controls (P> 0.05). The uncoated files of groups A.1, A.2 and A.3 displayed significantly lower maximum penetration depths (P< 0.05) when compared to the control files. CONCLUSIONS: Repeated sterilization under autoclave or exposure to sodium hypochlorite (NaOCl) prior to sterilization did not alter the cutting efficiency of PVD-coated NiTi K-files.

Analysis of Variance↗

PubMed2001

EID1, an F-box protein involved in phytochrome A-specific light signaling.

To perceive red and far-red light, plants have evolved specific photoreceptors called phytochromes. Even though the spectral properties of all phytochromes are very similar, they show a distinct mode of action. Here we describe EID1, a negatively acting component of the signaling cascade that shifts the responsiveness of the phytochrome A (phyA) signaling system associated with hypocotyl elongation from red to far-red wavelengths. EID1 is a novel nuclear F-box protein that contains a leucine zipper whose integrity is necessary for its biological function. EID1 most probably acts by targeting activated components of the phyA signaling pathway to ubiquitin-dependent proteolysis.

Alleles↗