Comparison of thermoplasticized gutta-percha root canal obturation technique to the lateral condensation

Exercise tolerance in postcardiac transplantation patients versus healthy controls was studied at different intervals after the surgery using bicycle ergometry. Being low after the transplantation, exercise tolerance in the patients increased throughout the rehabilitation period but still did not reach the values characteristic for healthy subjects. Initial heart rate in the above patients was higher, while chronotropic and inotropic reserves of the transplanted heart appeared lower than in the controls. The data obtained help objectively assess the condition of the patients with transplanted heart.     

An in vitro comparison of thermoplasticised gutta-percha obturation techniques with cold lateral condensation

This study compared the apical sealing ability, obturation time and extrusion of gutta-percha and sealer when root canals were obturated using either cold lateral condensation or one of the three methods using thermoplasticised gutta-percha (Alpha Seal, Thermafil or JS Quick Fill) in vitro. One hundred and thirty-one root canals from 78 extracted human teeth were used; 116 canals were divided into five groups so that they were balanced with respect to prepared canal anatomy, and the remaining 15 canals were used as positive and negative controls. The canals in the first four groups were prepared with hand files using the step-down technique to a standard apical size and flare. The last group was prepared using engine-driven rotary nickel-titanium files (McSpadden) to a similar apical size and flare. One of the four obturating techniques was used to fill the canals in each of the first four groups. The fifth group was obturated using the Alpha Seal technique. The roots were immersed in india ink, demineralised and rendered transparent to assess the extent of maximum lincar dye penetration. The Alpha Seal groups had the highest number of specimens without any leakage. There was a significant difference in the proportions of specimens that did not leak when the Alpha Seal (P < 0.01) and cold lateral condensation groups (P < 0.05) were compared with JS Quick Fill. Cold lateral condensation had a higher proportion of specimens with leakage in canals with curvature greater than 20 degrees than in canals with curvatures less than 20 degrees (P < 0.05). The curvature of canals had no effect on the sealing ability of the other techniques. The method of canal preparation had no effect on the sealing ability of Alpha Seal. Alpha Seal, Thermafil and JS Quick Fill were significantly quicker to perform than cold lateral condensation.     

Area-metric analysis of dye leakage for evaluation of sealing ability of root canal obturation techniques

Root canal sealing ability of obturation techniques has been assessed in vitro with various methods. The majority of the methods employ microleakage tracers and particularly dyes. In vitro measurements of dye penetration are either linear or volumetric. Area-metric analysis is a three dimensional registration method of dye leakage. The purpose of the present study was to evaluate in cleared teeth area-metric analysis as opposed to linear analysis of dye penetration. Forty freshly extracted single rooted human teeth were used. Instrumentation was carried out using Hedstroem files with a step back technique. The root canals were obturated using Roth sealer and qutta-percha cones and lateral condensation technique. The roots were then subjected to dye leakage tests under vacuum of 50 mmHg for 20 min. India ink was used as the tracer. The roots were randomly divided in two groups. In Group A the roots were cleared and linear measurements of the dye penetration were recorded The roots in Group B were ground stepwise transversally and subjected to area metric analysis. The results showed that area-metric analysis enabled sufficient recordings of the dye leakage patterns and the volume of the dye penetration could also be calculated.     

Scanning electron microscopic evaluation of two compaction techniques using a composite resin as a root canal filling material

The canals of 20 human dental roots were instrumented using a a step- back technique. The smear layer was removed, and the canals were obturated with composite resin. Two different techniques of compaction were used: either vertical or lateral motions were used to condense composite resin inside the root canal that was then photopolymerized layer by layer using the argon laser (488 nm). The beam was delivered into the root canal by means of an optical fiber 320 micrometers in diameter. Longitudinal and cross-sections of the samples and resin replicas of the root canals were examined using a light and scanning electron microscope. Scanning electron microscopic examination revealed that laterally compacted resin fillings showed fewer voids than those obtained by vertical compaction. In both experimental groups, adhesion of the resin to the dentin walls, pulled-out resin tags, microfailure, and resin fracture, leaving a layer of resin associated with the wall surface were observed.     

Effectiveness of two rotary instrumentation techniques for cleaning the root canal

An in vitro study was undertaken to compare the efficiency of two rotary endodontic devices for cleaning the root canal wall(s). Only mesial roots of mandibular first molar were used. Forty roots were classified into two equal groups. Group (I) was instrumented using the Canal Finder system, Group (II) was instrumented using Nickel Titanium files. In both groups half of the specimens received a final flush of 17% EDTA and 5.25% NaOCl solutions. Roots were sectioned longitudinally and Scanning Electron Micrographs were taken at three levels (Coronal, Middle and Apical) of each section of the prepared roots. Statistical analysis of the results showed that the Canal Finder system produced a clean canal surface when 17% EDTA and 5.25% NaOCL were used as an irrigating solutions, while Nickel Titanium files had a superior cleaning efficiency than the Canal Finder with either irrigating solution.     

Thermographic assessment of root canal obturation using thermomechanical compaction

The potential interaction is described between caffeine and antipyrine, two drugs with a high probability of being concomitantly administered for the evaluation of liver metabolism. In order to determine the influence of antipyrine on the elimination of caffeine, salivary caffeine clearance was measured in six healthy volunteers prior to and 2 and 5 days after the administration of a single oral dose of 1000 mg of antipyrine. Total caffeine clearance increased on average by 24% (from 1.65 to 2.05 ml/min, P = 0.1) 2 days after antipyrine dosing, and 25% (from 1.65 to 2.06 ml/min, P < 0.01) 5 days after the administration of antipyrine, whereas the half-life decreased by around 24% (from 5.3 to 4 h, P = 0.09) after 2 days and 26% (from 5.3 to 3.9 h, P = 0.05) after 5 days. The apparent volume of distribution did not change. These results suggest that antipyrine is able to increase the elimination of caffeine, probably by means of inducing its hepatic metabolism. When both drugs are used sequentially in the same patient to assess the drug metabolizing activity of the liver, the caffeine test should be performed first.     

Comparative study of two filling techniques using glass-ionomer (Ketac-endo) root canal cement on fracture resistance of endodontically treated roots (in vitro)

Forty freshly single rooted teeth were selected for this study. The coronal part of teeth were decapitated and the root canals were prepared by modified step-back technique with K-flex files to size 35# at the apex, five ml of 5.25% NaOCl was used as irrigating solution. According to the dentin thickness at the mesio-distal direction of the prepared roots, roots were divided into two groups: Group (I), dentin and cementum thickness from 1.5-2 mm, and Group (II), dentin and cementum thickness 1 mm. According to the filling technique used the teeth were subdivided into four subgroups each of five teeth; Subgroup (A) single gutta-percha cone and Ketac-endo root canal sealer, Subgroup (B) lateral condensation technique with gutta-percha and Ketac-endo sealer, Subgroup (C) laterally condensed gutta-percha with Roth 801 cement and Subgroup (D) teeth left unfilled as negative controls. The prepared roots were placed into acrylic resin so that 10 mm of the root was exposed. A slowly increasing force was applied vertically using a blunt punch with 1 mm tip thickness attached to Instron testing machine. The results showed that group (I) with 1.5-2mm dentin thickness required greater force to fracture in all experimental groups, than that of group (II) with 1 mm dentin thickness. So the amount of remaining dentin thickness significantly affected the resistance to fracture of the prepared roots.     

Apical sealing using two thermoplasticized gutta-percha techniques compared with lateral condensation

This study was conducted to compare the apical sealing capacity of three filling techniques, a multiphase gutta-percha obturation technique, JS Quickfill, and lateral gutta-percha condensation. A four-stage stepback preparation was executed with circumferential filing in a total of 70 recently extracted permanent maxillary incisors and canines. Three experimental groups (20 teeth in each group) and two control groups (5 teeth in each group) were formed at random. Each experimental group was obturated with a different technique. The positive control group was not obturated. In the negative control group, the whole root was covered with two full nail varnish layers. Teeth were immersed in India ink for 48 h, demineralized, cleared with methyl salicylate, and examined with a stereomicroscope. None of the specimens obturated with the multiphase gutta-percha obturation system showed any penetration of India ink beyond the end of the preparation. In the groups of teeth obturated by JS Quickfill or lateral gutta-percha condensation, leakage was detected in one specimen from each group. No statistically significant differences were seen among groups. We conclude that the newer thermoplasticized filling techniques can be used successfully to obturate root canals in large, straight roots.     

Comparative neurotoxic effects of root canal filling materials on rat sciatic nerve

The neurotoxic effects of the root canal filling materials--Endomethasone, N2 Universal, Traitement SPAD, Sealapex, and Calciobiotic Root Canal Sealer (CRCS)--were investigated on isolated rat sciatic nerves after local application. All of the canal filling materials reversibly inhibited the compound action potential (cAP) amplitudes. N2 Universal produced a 50% inhibition in 4.2 +/- 0.2 min. Traitement SPAD, Endomethasone, and CRCS produced the same inhibition in 6.4 +/- 0.3, 6.5 +/- 0.2, and 6.6 +/- 1.1 min, and Sealapex in 9.2 +/- 2.0 min. The inhibitory effect of Sealapex decreased fastest, and 43% recovery of cAP amplitude was observed in 60 to 70 min. The inhibitory effects of Endomethasone, CRCS, and N2 Universal were more pronounced, and 10 to 20% recovery in cAP amplitudes were observed in 2 h. The inhibitory effect of Traitement SPAD was more persistent with 4% recovery in 2.5 h.     

The use of a Hydroxyapol-containing zinc-eugenol paste for the filling of dental canals in treating periodontitis

Comparative assessment of the efficacy of two-staged treatment of patients with chronic apical periodontitis by hydroxyapol-containing paste and zink-eugenol paste demonstrated the desirability of adding hydroxyapol powder in the radical paste for the treatment of apical periodontitis.     

Root canal treatment of a mandibular first molar with three mesial root canals

A phlebotomist with nosocomially acquired human immunodeficiency virus infection developed tuberculosis 10 months after exposure to multidrug-resistant Mycobacterium tuberculosis during a nosocomial outbreak. Healthcare workers with immunosuppression are at increased risk of tuberculosis if infected and, if exposed, should be considered for preventive therapy regardless of tuberculin skin-test status.     

Prevalence of teaching apical patency and various instrumentation and obturation techniques in United States dental schools

Maintaining an open apex beyond the apical constriction with an endodontic file during canal instrumentation is a concept that has been advocated by several authors and clinicians. To ascertain the prevalence of teaching the patency concept as well as various instrumentation and obturation techniques in the United States dental schools, a survey was conducted. Forty-eight out of a total of 53 dental schools (91%) responded to the survey. Results indicate that 50% of the schools surveyed teach the concept of patency to their undergraduates or graduates or both; 83% teach a step-back instrumentation technique; and 89.6% teach lateral condensation of gutta percha as their primary obturation technique.     

An in vitro comparison of apical microleakage after obturation with JS Quick-Fill or lateral condensation

In order to investigate the blood supply of osteo-periosteal flap of lateral inferior part of tibia, 40 lower limbs of adult cadavers were observed. The result showed that the superior malleolar branch was the biggest branch on the lateral inferior part of tibia and served as the main blood supply to the above area. It originated from the anterior tibial artery, 3.1 +/- 0.8 cm above the intermalleolar line. During its way to the anterior border of the tibia, it gave out the ascending and descending branches. The ascending branch was along the anterior border upward and anastomosed with the musculo-periosteol branch of the anterior tibial artery at the level of 6.3 +/- 1.3 cm above the intermalleolar line. The decending branch was anastomosed with the anterior medial malleolar artery. For the anastomosis between the superior malleolar branch with the peripheral vessels, the osteo-periosteol flap could be designed at the lateral side of the lower part of tibia in size of 8-10 cm x 4-6 cm. This was a new donor area of osteo-periosteol flap for repair of non-union of bone in lower end of tibia or arthrodesis of the ankle joint.     

Comparison of two endodontic handpieces during the preparation of simulated root canals

The objective of this in vitro study was to compare and assess two endodontic handpieces during the preparation of simulated root canals. One hundred and sixty simulated root canals in clear resin blocks, of two angles and positions of curvature, were prepared using either Shaper files activated by the MM1500 Sonic Air handpiece (Micro-Mega, Besan?on, France) or Excalibur files activated by the W & H Excalibur 969 handpiece (W & H, Bürmoos, Austria). Files of 21-mm or 25-mm length were used. When preparing the canals, the files were used either in line with or perpendicular to the canal curvature. Preparation of the canals was carried out using a technique described in the manufacturers' literature. A variety of parameters were used to compare the handpieces, including an assessment of the canal preparation time, the deformation or fracture of instruments, loss of canal length, weight loss from the resin blocks and the overall postpreparation canal shape. Both handpieces provided an efficient and easy method of preparing and shaping the root canal with little operator fatigue. The MM1500 Sonic Air handpiece took significantly more time (P < 0.001) to prepare the canals and was associated with both more loss of working length (P < 0.05) and more loss of weight (P < 0.001). Both handpieces created a high percentage of aberrations in the shapes of prepared canals. The MM1500 Sonic Air handpiece created significantly more aberrations than the Excalibur handpiece (P < 0.05 for zip and elbow, P < 0.05 for danger zone and coronal narrow). The effects of the variables, canal curvature, file length and the plane of use of the file, on the performance of the handpieces, were also assessed.     

Restoration of external auditory canal by filling mastoid cavity with carbon pellet

Percutaneous suspension plasty, using Eickenberg's double-needle applicator, is a further development of the semi-open endoscopic method suggested by Stamey for precluding urinary incontinence in women. The operative technique is outlined, and the follow-up results in 53 patients are analyzes. This is a contribution to the broadening scope of endourologic and percutaneous operative technique.     

In vivo model for assessing the functional efficacy of endodontic filling materials and techniques

Endodontic fillings were challenged with bacterial ingress in mandibular premolars of 4 beagle dogs. Groups 1, 2, and 3 (n = 9), had canals filled with gutta-percha and sealer, gutta-percha alone, and sealer alone, respectively. After 2 wk, pulp chambers were inoculated with plaque. Group 4 (n = 9) and group 5 (n = 5) had canals either filled as in groups 1 to 3 or unfilled, respectively, but not inoculated. Group 6 (n = 5) had canals unfilled and inoculated. Teeth were radiographed periodically for 14 wk, dogs terminated, and jaw blocks retrieved and processed for light microscopic examination. Rarefying osteitis appeared in group 6 at 3 wk and in groups 2, 3, and 5 at 11 wk. Periradicular inflammation was none, mild, or severe. Occurrence of severe inflammation in groups 1 to 6 was 0, 11%, 33%, 0, 60%, and 100%, respectively. Groups 1 to 3 combined differed significantly from group 4 (repeated-measures ANOVA, p < 0.05). This model could be used to assess the functional efficacy of endodontic fillings in vivo.     

大直径深孔侧向崩矿充填采矿法底部结构优选

保山金厂河矿主矿体ZnV3为缓倾斜中厚矿体,矿岩界线明显,属中等稳固类型,采用大直径深孔侧向崩矿充填采矿法开采的比例为78％,底部结构的选择成为制约该采矿方法能否成功应用于该矿体开采的关键.根据开采技术条件,提出了V型堑沟受矿和平底受矿2种底部结构,对比分析了2种底部结构的工程量、工作效率、经济性及安全性,最终得出V型...