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At least 397 records · Page 22Linked to original sources
PubMed2000

Canal shapes produced sequentially during instrumentation with Quantec LX rotary nickel-titanium instruments: a study in simulated canals.

AIM: The aim of this study was to determine the shaping ability of Quantec LX nickel-titanium rotary instruments in simulated root canals. METHODOLOGY: Forty simulated canals consisting of four different shapes in terms of angle and position of curvature were prepared with Quantec LX instruments. Sequential still images were taken of the canals using a video camera attached to a computer with image analysis software. Images were taken preoperatively; after, instrument 7 (Size 25, 0.05 taper), instrument 8 (size 25, 0.06 taper), and instrument 10 (size 45, 0.02 taper) were taken to length. Each sequential postoperative image was superimposed individually over the preoperative image in order to highlight the amount and position of material removed during preparation. Intra-canal impressions after preparation to size 10 were taken to evaluate three-dimensional canal form. RESULTS: Overall, the mean preparation time to size 10 was 4.7 min; canal shape did not have a significant effect on speed of preparation. No instruments fractured within the canal, but 7 instruments separated from the latch grip, and a further 3 instruments deformed. All canals remained patent. Following preparation to size 10, 29 canals (72%) retained their length, 7 (17%) lost length, and 4 gained length; the magnitude of the change in length was always below 1 mm. Zips were created in 3 canals (7%) after use of size 10 instruments, but no perforations or danger zones were produced. Excess removal of material along the outer aspect of the curve between the beginning of the curve and the end-point (outer widening) was found in 22 canals (55%) after instrument 7, in 30 (75%) canals after size 8 and in 35 canals (88%) after size 10. There was a significant difference (P < 0.0001) between canal shapes for the incidence of this aberration at all sizes. CONCLUSIONS: Under the conditions of the study, Quantec LX instruments tended to remove excess material from the outside of the curve between the beginning of the curve and the end-point. These aberrations increased in prevalence and severity following the use of larger instruments when they were taken to length. Size 8, 9 and 10 Quantec LX instruments should be used with care and short of length, especially in severely curved canals.

Analysis of Variance↗
PubMed2000

An in vitro comparison of canal preparation using two automated rotary nickel-titanium instrumentation techniques.

AIM: The aim of this study was to compare the efficacy of root canal preparation using two automated rotary nickel-titanium instrumentation techniques with a double flared balanced forces hand preparation technique, using stainless steel files in extracted human teeth. METHODOLOGY: Sixty root canals in extracted human teeth were matched for curvature, length and diameter and divided evenly between three groups (group 1 = double flare using Flexofiles, group 2 = rotary nickel-titanium using McXIM instruments and group 3 = rotary nickel-titanium using Profile .04 Taper Series 29 instruments). The instruments were used according to the manufacturer's instructions in a torque controlled motor and handpiece (groups 2 and 3) and according to a predetermined procedure in group 1. A standardized radiographic technique using mercury as a contrast medium was used to evaluate the canal shape before and after preparation in the plane of maximum curvature. The pre- and postoperative radiographic images were compared against each other and with a predicted 'ideal preparation' calculated from a projection of the final instrument dimensions. The outcome measures were changes in canal dimensions as quantified by measuring the changes in the position of the inner and outer wall at 1 mm intervals. Alteration in canal curvature could be inferred by comparison with the ideal preparation. RESULTS: The degree of canal curvature did not influence the effectiveness of any of the techniques. The results showed no statistically significant differences in the outcome measures between the groups (two-way ANOVA). There were no significant differences in canal wall position changes at any level except the apical three, where significantly less change occurred in all groups (P = 1%). Instruments fractured in three canals, with acute curves in groups 2 and 3. CONCLUSIONS: Canal curvatures were equally and well maintained following preparation in all the groups, as long as the instrument did not fracture.

Analysis of Variance↗
PubMed2001

Effect of access cavity location and design on degree and distribution of instrumented root canal surface in maxillary anterior teeth.

AIM: The null hypothesis tested in this study was that in single-rooted anterior teeth with simple root canal anatomy, different access cavity designs ('lingual cingulum', 'lingual conventional', 'incisal straight-line') do not influence the ability of endodontic files to plane the walls of the root canals. METHODOLOGY: Thirty extracted human maxillary anterior teeth were divided randomly into three groups for each access cavity. The access cavities were prepared according to predefined criteria and the roots embedded in individual polyvinyl-siloxane putty matrices. The matrices allowed these teeth to be split into buccal and palatal halves and to be reassembled. The split teeth enabled removal of pulpal remnants from the root canal system and the walls to be stained with an even layer of permanent black ink. Once dried, the split roots were reassembled in the putty matrices and a step-back filing technique was used to prepare the canals with water irrigation. The canal walls were examined for residual ink staining and scored by three independent assessors using an index devised for the purpose. RESULTS: There was good agreement between the assessors. None of the access cavities allowed file contact with the entire root canal wall. The overall (palatal and buccal sections) scores showed significant differences (P < 0.01) between the access cavity groups in the extent to which the canal walls could be filed. The straight-line incisal access cavity had the greatest proportion of instrumented root canal surface. The lingual cingulum access cavity was the worst in this respect. The differences in residual ink scores between the access cavity types were significant for the buccal halves (P < 0.01) but not for the palatal halves (P > 0.05). CONCLUSIONS: The null hypothesis was proven. Regardless of access cavity design, mechanical preparation did not allow instrumentation of the entire root canal wall. Straight-line access allowed the greatest proportion of the root canal wall to be instrumented and the lingual cingulum access the least.

Chi-Square Distribution↗
PubMed2001

The standardized-taper root canal preparation--Part 3. GT file technique in large root canals with small apical diameters.

AIM: To describe the preparation of Large Root canals with small apical diameters by the GT file technique. SUMMARY: Large Root canals with small apical diameters can usually be prepared with one to three GT files; one to nine clinical steps, and one to five minutes of clinical time. Following proper access, pulp tissue should be removed, and lubricant applied to prevent pulp compaction and blockage. Initial crown-down enlargement is accomplished with up to three standard GT rotary files 0.10, 0.08 and 0.06 taper, running at 300 r.p.m., and with light touch. Care should be taken not to overload instruments, and they should be withdrawn, cleaned and inspected whenever they bind. Sometimes, the shaping objective is achieved with a single instrument; often waves of instrumentation are required before the shaping objective file cuts to length. Prior to cone-fit, the apical resistance form is confirmed with conventional files, employed as feeler gauges of the tapering form created at the canal terminus. Regardless of the shaping time, canals should be soaked with sodium hypochlorite solution for at least 30 min for effective cleaning. KEY LEARNING POINTS: Large Root canals with small apical diameters should be prepared to shaping objectives 0.08 or 0.10 taper. Compacted pulp tissue causes many canal blockages. It should be removed early, and canals should be well lubricated. Large Root canals with small apical diameters should be prepared in crown-down sequence, with recapitulation of steps until the shaping objective is achieved. Apical resistance form should always be confirmed before cone-fit. Canals should be exposed to sodium hypochlorite for at least 30 min for effective cleaning.

Dental Pulp Cavity↗
PubMed2001

The standardized-taper root canal preparation--part 5. GT file technique in small root canals.

AIM: To describe the shaping of Small Root canals with GT files. SUMMARY: Small Roots are lower incisors, two and three canal bicuspids, buccal roots of upper molars, and mesial roots of lower molars. The Shaping Objective instrument for such cases is usually a 0.08 or 0.06 taper GT file. After proper access, pulp tissue should be removed to prevent its compaction and canal blockage. Orifice shaping and smoothing is then achieved with a 35-0.12 accessory GT File, running at full slow-speed r.p.m. (5-20K).Crown-down preparation commences with the 0.10 GT file, followed by the 0.08 and 0.06 tapers as needed. Occasionally, a 20-0.04 Profile is required to reach length. Files are rotated at 300 r.p.m. with steady, light pressure, and withdrawn frequently for cleaning and inspection. Once one of these files has cut to length, the canal terminus is enlarged to Shaping Objective. If difficulty is encountered, be willing to accept a 0.06 instead of the original 0.08 taper Shaping Objective. If the terminal diameter is 0.2 mm you will have plenty of apical resistance form in a tortuous canal with the 0.06 taper preparation. It is definitely better to end up with a smaller shape than originally planned, than to experience the heartache of separation. KEY LEARNING POINTS: Small Root canals should be prepared to a Shaping Objective 0.08 or 0.06 taper. Pulp tissue should be removed before preparation to prevent compaction and blockage. Preparation follows in a crown-down sequence, and may occasionally require the use of small Profiles. Final apical shaping is easily achieved when root length is reached.

Bicuspid↗
PubMed2001

The standardized-taper root canal preparation--part 6. GT file technique in abruptly curved canals.

AIM: To describe the application of GT files in roots with abrupt curvatures. SUMMARY: Most dentists interpret obstructions to instrument progress as calcification, rather than abrupt curvature. Basically, there are not any apically calcified canals, only clinicians who are not clever enough or patient enough to sneak to patency. Dentists should be on their guard and sensitive to the 'rubber band' sensation of residual pulp tissue, and the 'loose resistance' sensation of the curved or ledged canal. Residual pulp tissue should be removed and the canal lubricated. The ledged or curved canal will only be helped by file bending. The size 10 file test is the key to identify canals requiring pre-bent instruments. The canal should first be flared short of the obstruction, before shaping the canal after it with regular, pre-bent K-files. Pre-bent GT hand-files can then be used with care to blend the apical and more coronal regions for final shape. Cone-fit may then require chilling and pre-bending GP cones (pre-bend more than one), before packing the canal. KEY LEARNING POINTS: Root canals do not calcify apically. File progress is prevented by pulp tissue, abrupt curvatures or ledging. Loose resistance to the passage of a size 10 file shows the canals that require instrument pre-bending. This test should be repeated at intervals during the preparation. Even NiTi GT files can be pre-bent for use in abrupt curves. Gutta percha cones can be pre-bent after chilling.

Dental Pulp Cavity↗
PubMed2002

Periapical changes following root-canal treatment observed 20-27 years postoperatively.

AIM: The aim of the present study was to identify periapical changes 20-27 years after root-canal treatment. METHODOLOGY: The periapical condition of 265 roots filled by undergraduate students was evaluated in two series of intraoral radiographs taken 10-17 and 20-27 years after treatment. Roots (72) not recorded with a normal periapical situation on both occasions by two observers, were re-evaluated by other two examiners, separately and jointly. Final decisions about diagnoses were made by all four examiners. A strict definition was used for the identification of cases with an unfavourable outcome. RESULTS: Favourable outcomes were observed in 6.4% of the roots that had radiolucencies at the 10-17-year follow-up. Periapical radiolucencies after 20-27 years appeared in 1.5% of all other roots. The radiographic failure frequency for the total material was 4.9%. The percentage of cases with normal periapical findings at the final follow-up was 86.4%, whilst 8.7% were recorded with increased width of the apical periodontal space. Delayed healing owing to surplus root-filling material explained nearly all of the cases with favourable outcome assessed many years after treatment. CONCLUSIONS: Late periapical changes, with more successes than failures, were recorded when a 10-17-year follow-up period after root-canal treatment was extended for another 10 years.

Follow-Up Studies↗
PubMed2003

Preliminary in vitro evaluation of Carisolv as a root canal irrigant.

AIM: To test the null hypothesis that Carisolv is no better than PBS in removing organic debris from uninstrumented root canals. METHODOLOGY: The pulps of two uniform groups of 36 immature, sheep mandibular incisors were grossly removed with barbed broaches immediately prior to the study. Roots in group 1 were irrigated with phosphate buffered saline (PBS), strong sodium hypochlorite (4.5%) or Carisolv without ultrasonic agitation, whilst in group 2 the same irrigants were activated with ultrasound. Canal walls were exposed to irrigants for 10, 20 or 30 min at 37 degree C. In group 2, ultrasound was applied for 30 s at 2, 5 and 7 min within each 10 min incubation period. After washing irrigants free and immersion in fixative, all teeth were split longitudinally, critical point dried and sputter coated for SEM analysis. SEM photomicrographs were recorded of representative areas in the coronal, middle and apical canal thirds and debris scored by a single assessor against a five-point scale. Intraobserver reliability was assessed by Cohens kappa scores and debris scores analysed by the non-parametric Kruskal-Wallis test at P < 0.05. RESULTS: Sodium hypochlorite was significantly better than Carisolv and PBS in cleaning root canals (P < 0.0001), whether or not ultrasound was applied. Carisolv was shown to clean canals better than PBS, again whether or not ultrasound was applied (P = 0.01). Both incubation time and ultrasound enhanced the action of Carisolv (P < 0.001) whilst the activity of PBS was not significantly improved by exposure time or the application of ultrasound. Kappa scores of 0.90-0.95 indicated excellent consistency in debris scoring. CONCLUSIONS: Within the limitations of this preliminary study (i). Carisolv cleaned root canals better than PBS and shows promise as an adjunct to root canal preparation; (ii). the action of Carisolv was enhanced by incubation times beyond 20 min whether or not ultrasound was applied; (iii). sodium hypochlorite solution remains the gold standard endodontic irrigant, provided that it is used with care and is contained in the canal system.

Animals↗
PubMed2003

Percentage of filled canal area in mandibular molars after conventional root-canal instrumentation and after a noninstrumentation technique (NIT).

AIM: To compare the percentage of filled canal area in mandibular molar roots after using conventional root-canal hand instrumentation or after a noninstrumentation technique (NIT). METHODOLOGY: Forty mandibular molars were used shortly after extraction. The root canals of 20 molars in the manual group were conventionally prepared using hand instruments and then filled with warm vertical compaction of gutta-percha. The 20 teeth in the second group were cleaned and obturated by NIT. In each case, the entire molar, including the crown and the roots, was embedded in an acrylic resin cylinder before NIT. Horizontal sections were cut at 2, 4, 6 and 8 mm from the apex. Images of the sections were taken using a microscope at x40 magnification and a digital camera; the images were scanned as Tagged Image File Format (TIFF) images into a PC. The cross-sectional area of the canal with the filling materials was measured using an image analysis programme. The percentage of filled area was calculated. The difference in the percentage of filled canal area between the two groups was analysed using a Student's t-test. RESULTS: At all levels, 93-100% of the canal area was filled in both groups. No significant difference was found between the manual technique and the NIT technique at any level (P>0.05). CONCLUSIONS: Within the limitations of this study, following the cleaning and filling of root canals using NIT, the percentage of filled root canal was similar to that using warm vertical compaction of gutta-percha after conventional root-canal instrumentation.

Adult↗
PubMed2003

Catalase activity in human healthy and inflamed dental pulps.

AIM: To examine the catalase activity in clinically healthy and symptomatic human dental pulps to verify if an active defence system against oxidizing agents is present as a response to bacterial invasion. METHODOLOGY: Thirty-three systemically healthy patients, 18 females and 15 males (ages: 11.0-25.9 years; mean 18.8 +/- 3.6), were the source of the pulp tissue. The condition of the pulps was assessed using clinical and radiographic evaluations. The specimens were recovered by longitudinally grooving and splitting the teeth (if extracted) or during endodontic treatment, and were matched for age and sex between the healthy and inflamed specimen groups. Catalase activity was determined through spectrophotometric methods. RESULTS: Enzymatic activity was 1126 +/- 343 and 3074 +/- 698 mU mL(-1) x mg of total protein in the healthy and inflamed pulp tissue specimens, respectively. This difference was statistically significant (P<0.01). CONCLUSIONS: These results indicate a role for catalase during dental pulp inflammation in humans, and may represent an inherent biological defence system against reactive oxidants of this tissue.

Adolescent↗
PubMed2003

A combined radiographic and computerized scanning method to evaluate remaining dentine thickness in mandibular incisors after various intracanal procedures.

AIM: To develop a computerized model to evaluate remaining dentine thickness after various intracanal procedures. METHODOLOGY: A three-step model was developed, in which injection of radiopaque solution into the root-canal space of 20 extracted mandibular incisors, exposure of periapical radiographs from two directions, and computerized scanning and printing of the image were combined. Following root-canal preparation and preparation of post space, evaluation of remaining dentine thickness was completed using appropriate software. RESULTS: Remaining dentine thickness was significantly affected (P < 0.01) by place (mesial-distal more than buccal-lingual), stage (root-canal preparation more than post space) and location (coronal more than middle and apical). CONCLUSIONS: This in vitro study confirmed that in an oval root-canal space, the mesial and distal aspects are mainly affected by intraradicular procedures. The three-step method is a useful tool to evaluate root-canal instrumentation as the root or tooth can remain intact during the procedure.

Contrast Media↗
PubMed2001

Revascularization after cryopreservation and autotransplantation of immature and mature apicoectomized teeth.

Autotransplantation of immature teeth can have a success rate of almost 98% if the tooth is atraumatically transplanted from the donor site to a suitable acceptor site and the extraoral time is kept to a minimum. When the tooth cannot be transplanted immediately, cryopreservation and storage in a tooth bank offer new possibilities for autotransplantation. However, the effect of cryopreservation on the revascularization of transplanted teeth is still unknown. The purpose of this study was to examine revascularization in immature teeth that have an open apex and in mature teeth that have had the apex cut. The study was carried out on 16 teeth in 2 dogs; 8 teeth were removed and immediately transplanted to the contralateral position and 8 teeth were cryopreserved and transplanted 1 week later. The results show that: (1) teeth can revascularize after autotransplantation if the original pulp tissue is removed at the time of extraction, (2) there is no significant difference in the amount of revascularization between teeth stored in a tooth bank for 7 days and those immediately transplanted without freezing, and (3) there is no difference in the ingrowth of new pulpal tissue between mature apicoectomized teeth and immature teeth.

Angiography↗
PubMed2001

A comparison of Greater Taper files, ProFiles, and stainless steel files to shape curved root canals.

OBJECTIVE: The purpose of this study was to evaluate the ability of engine-driven nickel-titanium files to maintain the original curvature of root canals during canal preparation. STUDY DESIGN: A total of 36 simulated curved canals on resin blocks were instrumented with Greater Taper (GT) files, ProFiles, and stainless steel files. With the mounting device, which can reproduce the same position of the resin blocks and the camera, the unprepared and prepared canals were accurately compared by means of a double-exposure photographic technique. The analysis of variance test was used for the statistical analysis of data obtained. RESULTS: The canals prepared by means of a ProFile with a 6% taper up to the working length were excellent in taper and in maintaining the original curvature. The canals prepared with GT files were also found to be excellent in taper and in maintaining the original curvature; however, these canals showed a slight enlargement toward the inner side at the beginning of the curvature. The canals prepared with stainless steel files showed nontapered widening and severe transportation. CONCLUSION: The canals prepared with GT files and ProFiles were excellently tapered and maintained the original curvature of the canals in comparison with the ones prepared with stainless steel files.

Analysis of Variance↗
PubMedDate not supplied

Dental management of pediatric patients undergoing hematopoietic stem cell transplant.

This study was conducted to evaluate the outcomes of a dental management program the authors designed for pediatric patients receiving hematopoietic stem cell transplant (HSCT) for hematological malignancy. Thirty pediatric patients with hematological malignancies received dental management before HSCT. The outcomes of the dental management and any episode of odontogenic complication were retrospectively evaluated. The pretransplant oral examination showed one or more dental pathologies in 19 children (63.3%), and the remaining 11 patients showed no dental pathologies. Fifteen of the 19 children with dental pathologies received dental treatment, which included restoration, tooth-brushing instruction, scaling, endodontic therapy for permanent teeth, and extraction of primary teeth. No odontogenic infection occurred in any patient during the immunosuppressive period.

Adolescent↗
PubMed2000

Shaping ability of three ProFile rotary instrumentation techniques in simulated resin root canals.

The aim of this study was to compare the shaping ability of three ProFile rotary instrumentation techniques and a conventional step-back method in simulated root canals. Prevalence of canal aberrations, change in working length, and preparation time were measured. A total of 48 composite images were made from pre- and postcanal scanned images using Corel Photopaint 8.0 and then the amount of coronal substance the instruments removed was also calculated two-dimensionally on digitized images with the Brain C software to compare the enlarging efficiency. There were no significant differences between the three rotary groups in preparation time, change in working length, and the incidence of aberrations (p > 0.05). The amount of coronal substance the instruments removed in the ProFile .04 taper group was significantly smaller than the other three groups (p < 0.05).

Carbon↗