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Results for “Tooth Apex”

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At least 721 records · Page 40Linked to original sources

PubMed2005

In-vitro evaluation of microleakage of an orthograde apical plug of mineral trioxide aggregate in permanent teeth with simulated immature apices.

This in vitro study evaluated the seal created by varying depths of mineral trioxide aggregate (MTA) plugs placed in an orthograde fashion in five groups of 10 teeth. One group received a 2 mm thick orthograde apical plug of MTA, the second group a 5 mm apical MTA plug, and the third group a 2 mm apical MTA plug with a second 2 mm increment, 24 h later. The remaining portion of the canal in these groups was left unfilled. Group four received a 2 mm MTA plug that set for 24 h and the canal was then back-filled with gutta-percha and eugenol based sealer. Group five was a positive control without an MTA plug. The apical seal was tested using a bacterial leakage model of Actinomyces viscosus. Results showed a statistically significant difference in only the 5 mm apical plug, which completely prevented bacterial leakage.

Actinomyces viscosus↗

PubMed2005

The influence of a manual glide path on the separation rate of NiTi rotary instruments.

The dual purpose of this study was, to evaluate the fracture rate of Ni-Ti rotary instruments when following a manual glide path and using stainless steel hand files before carrying out instrumentation by means of rotary files and, to compare the results in this study with those obtained in two previous analyses, in which the glide path technique was not used. A total of 208 canals obtained from a pool of freshly extracted human mandibular and maxillary molars was divided into three groups corresponding to; K3, ProFile and ProTaper. The coronal 2/3 of each tooth were used. In all three groups the apical portion of the samples was prepared with size 10-20 stainless steel K-type hand files. The apical stops were prepared using K3, ProFile and ProTaper rotary instruments. Logistic regression model analysis indicated that breakage was significantly associated with the angle of curvature of the canal (OR = 1.078; 95% CI = 1.032-1.12; p = 0.001), and with the number of clinical uses (files used more than eight times broke more frequently that those used 1 or 2 times; OR: 22.686; 95% CI: 2.6-191.3; p = 0.004). The breakage rate obtained in the present study is significantly lower than in our previous studies, in which the angle of curvature was also greater than 30 degrees and rotational speed a constant 350 rpm, but in which the canals were not first prepared with hand files (25/205 = 12% versus 16/61 = 26%, p = 0.007). Based on the results of this study, we recommend the use of stainless steel hand files to prepare the apical 1/3 of curved canals before introducing rotary files.

Dental Alloys↗

PubMed2005

Quality of gutta-percha root canal fillings using differently tapered gutta-percha master points.

The aim of this study was to evaluate the quality and adaptability of gutta-percha root canal fillings to the root canal walls when two different tapered gutta-percha master points (GPMP) were used to fill a split-tooth model. A maxillary central incisor was prepared for the split-tooth model and 10 fillings for group A (ISO .02 GPMP) and group B (ISO .10 GPMP) were carried out. The System B and the Obtura II were used to fill the split-tooth model and replication of round artificial depressions, voids within the gutta-percha (GP) and spaces between the GP and the root canal walls were evaluated and scored. Individual scores of each parameter evaluated were compared between the two groups and statistically analyzed using the Mann-Whitney U test. Group A showed statistically significant better scores (p < 0.05) for the replication of the artificial round depressions and spaces between the GP and the root canal walls. No statistically significant differences were found between the two groups for internal voids. It is concluded that the location of the GPMP binding point and the greater mass of the .10-Tapered GPMP may affect the quality and adaptation of the root canal filling in the important apical part of the canal.

Gutta-Percha↗

PubMed2005

An in vitro comparison of the sealing ability of three endodontic sealers used in canals with iatrogenic enlargement of the apical constriction.

In cases of disrupted apical constriction effort is made to create an apical stop and subsequently instrument and obturate the canal up to this point. The aim of this study was to in vitro evaluate the sealing ability of three root canal sealers used with the lateral compaction technique in teeth with enlarged constriction. Thirty-six single rooted premolars with straight canals were instrumented up to the apical constriction using a step-back technique. The constriction was enlarged and root canal instrumentation 1.5 mm short of the original working length was performed, to create a new apical stop. Teeth were obturated using lateral compaction technique with either Topseal, Roth 811, or Apexit. Teeth were subjected to area-metric analysis of dye penetration in transverse root sections, up to the most coronal extend of the dye. Sections were studied under the stereomicroscope, digital images were processed and leakage area was estimated. Statistical analysis was performed using Student's t test and Wilcoxon matched-pairs signed-rank test. No gutta-percha was extruded into the space between the apical constriction and the new iatrogenically created constriction. Topseal showed statistical significant less leakage. No significant difference was found between Apexit and Roth 811 (t = 0.99; p = 0.75).

Bicuspid↗

PubMed2005

Comparison of generated forces and apical microleakage using nickel-titanium and stainless steel finger spreaders in curved canals.

The purpose of this study was to compare (a) forces generated during lateral compaction and (b) apical microleakage for nickel-titanium (NiTi) and stainless steel (SS) finger spreaders. Twenty-eight extracted human teeth were instrumented using a standardized rotary instrumentation technique. NiTi and SS #30 spreaders were used to obturate molar roots while the forces generated during obturation were measured on a Universal testing machine. Apical microleakage was determined using a fluid filtration method. There was no significant difference in microleakage between spreaders. NiTi spreaders produced significantly less force than SS spreaders in all specimens (p < 0.001).

Dental Alloys↗

PubMed2005

The shaping effects of three nickel-titanium rotary instruments in simulated S-shaped canals.

The purpose of this study was to compare the shaping effects of three nickel-titanium rotary instruments, ProTaper, K3, and RaCe, with emphasis on canal transportation. Simulated canals with an S-shaped curvature in clear resin blocks were prepared with a torque-control, low-speed engine. Canals were prepared using the crown-down technique to the size of #30. Canal aberrations were assessed by comparing the pre- and postinstrumentation images under a stereomicroscope. ProTaper instruments caused greater widening of canals compared to K3 or RaCe. Furthermore, ProTaper files showed a tendency to ledge or zip formation at the end-point of preparation. These canal aberrations may be caused by ProTaper finishing files, which appear to be less flexible than other files of the same tip-size, because of their greater taper-size. These results suggest that nickel-titanium file systems including less tapered, more flexible instruments, like K3 and RaCe should be used in the apical preparation of canals with a complicated curvature.

Dental Alloys↗

PubMed2005

Preliminary evaluation of BMP-2 expression and histological characteristics during apexification with calcium hydroxide and mineral trioxide aggregate.

Histological characteristics and bone morphogenetic protein-2 (BMP-2) expression were evaluated in apexification procedures using calcium hydroxide [Ca (OH)2] and mineral trioxide aggregate (MTA). In three of four quadrants of the mouth, monkey (Macaca fascicularis) teeth were infected by pulpal exposure to saliva. After 90 days, each group was treated with Ca (OH)2 or MTA. Infected, untreated teeth were used as negative controls and normally developing teeth were used as positive controls. Areas within the apical region of each sample were scored based upon histological findings and BMP-2 expression. Overall, BMP-2 expression in all areas was similar in the Ca (OH)2, MTA, and infection/no treatment groups, which tended to be more immunoreactive for BMP-2 than the untreated group. Use of MTA in combination with Ca (OH)2 may initiate regeneration of the periodontium more quickly than either material used alone, but further studies involving MTA use in apical closure are indicated.

Aluminum Compounds↗

PubMed2005

Disinfection of immature teeth with a triple antibiotic paste.

This study assessed the efficacy of a triple antibiotic paste in the disinfection of immature dog teeth with apical periodontitis. The canals were sampled before (S1) and after (S2) irrigation with 1.25% NaOCL and after dressing with a triple antibiotic paste (S3), consisting of metronidazole, ciprofloxacin, and minocycline. At S1, 100% of the samples cultured positive for bacteria with a mean CFU count of 1.7 x 10. At S2, 10% of the samples cultured bacteria-free with a mean CFU count of 1.4 x 10. At S3, 70% of the samples cultured bacteria-free with a mean CFU count of only 26. Reductions in mean CFU counts between S1 and S2 (p < 0.0001) as well as between S2 and S3 (p < 0.0001) were statistically significant. These results indicate the effectiveness of a triple antibiotic paste in the disinfection of immature teeth with apical periodontitis.

Animals↗

PubMed2005

Remaining dentin thickness in the apical 4 mm following four cleaning and shaping techniques.

The aim of this study was to determine the remaining dentin thickness (RDT) in the apical 4 mm following four cleaning and shaping techniques. Sixty human adult extracted mandibular incisors and 60 mesial buccal canals of mandibular molars were assigned to five groups of 12 teeth for each tooth type: Step-down stainless steel hand instrumentation, Lightspeed, Profile GT and 0.4 taper, K3 "g pack," control group. After instrumentation the teeth were sectioned at 0.5, 1.5, 2.5, and 3.5 mm short of working length (WL) and evaluated for the minimum RDT at each level. ANOVA of RDT showed significant differences among levels and techniques. For incisors, no technique yielded greater RDT than the other techniques (p < 0.0001). For molars, K3 had greater RDT than the other techniques (p = 0.0006) at the 1.5, 2.5, and 3.5 mm levels. While there were significant statistical differences in RDT among techniques at different levels, further study would be required to determine any significant clinical difference in RDT.

Adult↗

PubMed2005

Sealer penetration and apical microleakage in smear-free dentin after a final rinse with either 70% isopropyl alcohol or Peridex.

Tensioactive agents may alter dentinal wettability allowing increased sealer penetration into dentinal tubules. This may improve the apical seal and better entomb remaining bacteria. The purpose of this study was to determine if a final rinse with either 70% isopropyl alcohol or Peridex in instrumented, smear-free canals would affect apical microleakage or Roth's 801 sealer penetration into dentinal tubules. Sixty root segments were instrumented followed by smear layer removal. The segments were randomly divided into three groups receiving a final rinse with 6% sodium hypochlorite (NaOCl), 70% isopropyl alcohol or Peridex. Obturation was completed using lateral compaction and Roth's 801 sealer pigmented with carbon black. Microleakage was measured by fluid filtration. Sealer penetration was measured using light microscopy. No significant differences were found between groups for microleakage or sealer penetration. Although a final rinse with either 70% isopropyl alcohol or Peridex did not increase sealer penetration, neither significantly affected apical microleakage compared to NaOCl.

2-Propanol↗

PubMed2005

Ultrastructural evaluation of the apical seal in roots filled with a polycaprolactone-based root canal filling material.

This in vitro study compared the ultrastructural quality of the apical seal achieved with Resilon/Epiphany and gutta-percha/AH Plus. Single-rooted extracted human teeth were prepared using a crown-down technique, debrided with NaOCl and EDTA, and obturated with either Resilon/Epiphany or gutta-percha/AH Plus. They were examined for gaps along canal walls using SEM, and for apical leakage using a transmission electron microscopy (TEM). SEM revealed both gap-free regions, and gap-containing regions in canals filled with both materials. TEM revealed the presence of silver deposits along the sealer-hybrid layer interface in Resilon/Epiphany, and between the sealer and gutta-percha in the controls. It is concluded that a complete hermetic apical seal cannot be achieved with either root filling materials.

Dental Leakage↗

PubMed2005

Effect of root canal filling/sealer systems on apical endotoxin penetration: a coronal leakage evaluation.

Endotoxin, elaborated by gram-negative organisms, is an important factor in apical periodontitis. The objective of this study was to evaluate the magnitude of endotoxin penetration through root canal treated teeth using a dual chamber model system. Forty-four maxillary anterior teeth were prepared endodontically and canals filled either by lateral condensation or a warm thermoplasticized technique in combination with either Roth's 801 or AH 26 sealer. Teeth were suspended in the model system with a mixed anaerobic bacterial suspension in the upper chamber and HBSS in the lower chamber. The QCL-1000 LAL assay was used to measure endotoxin at 0, 1, 7, 14, and 21 days. Response feature analysis using trapezoidal area under the curve was performed; the four treatment groups were compared using nonparametric methods. Groups differed (p = 0.028), with thermoplasticized root canal filling/Roth's 801 sealer permitting the least apical endotoxin penetration. Results suggest that Roth's 801 sealer may have a role in inhibiting endotoxin penetration.

Analysis of Variance↗

PubMed2005

Properties of a new root-end filling material.

The purposes of this investigation were 2-fold: to study the physical properties and sealing ability of Viscosity Enhanced Root Repair Material (VERRM); and, to compare them with Mineral Trioxide Aggregate (MTA). VERRM has a composition similar to mineral trioxide aggregate, with handling characteristics and consistency similar to commercially available materials such as IRM and Super EBA. The pH, setting times, solubility, radiopacity, dimensional change upon setting, and apical sealing ability of VERRM were evaluated and compared to that of ProRoot MTA (GMTA) and ProRoot MTA (Tooth Colored Formula) (WMTA). The results showed that VERRM had physical properties similar to WMTA. VERRM and WMTA showed significantly greater dye penetration than GMTA (p < 0.05) when used as a root-end filling material. There was no significant difference in depth of dye penetration between VERRM and WMTA. Further development of VERRM is indicated to produce a biocompatible root-end filling material with superior handling characteristics.

Aluminum Compounds↗

PubMed2005

An in vitro model to investigate filling of lateral canals.

Aims of this work were to examine lateral canals in extracted teeth, to propose a new technique to produce artificial lateral canals, and to compare two obturation techniques. Cleared roots were examined to record measure and shape of lateral canals. Artificial lateral canals were prepared on human demineralized teeth before final clearing. Specimens were divided in two groups: canals of group 1 were filled with Schilder's technique, canals of group 2 were filled with vertical compaction with apical backfilling. Stereomicroscopic analysis of lateral canal filling revealed lower filling rates in apical canals compared to coronal ones and higher filling rates with "vertical compaction with apical backfilling" compared to Schilder's group. The tested procedure appears to be a reliable technique to obtain standardized lateral canals and to compare filling procedures.

Decalcification Technique↗

PubMed2005

Apical leakage of resin based root canal sealers with a new computerized fluid filtration meter.

In this in vitro study, the apical leakage of three root-canal sealers: AH Plus, Diaket, and EndoREZ was evaluated using a new computerized fluid filtration meter. Forty-five extracted human premolar teeth with single root and canal were used. The coronal part of each tooth was removed and the root canals were prepared using GT Rotary files and crown-down technique. The roots were randomly divided into three groups of 15 samples, filled with one of the test materials and gutta-percha cones by the cold lateral condensation technique and were stored at 37 degrees C and 100% humidity for 7 days. One-week later, apical parts of roots of 10 +/- 0.05 mm were attached to computerized fluid filtration meter. Apical leakage quantity was determined as microl/cmH(2)O/min(-1). Statistical analysis indicated that root fillings with Diaket in combination with cold lateral condensation technique showed lower apical leakage than the others (p < 0.05). In addition, this new computerized fluid filtration meter allowed quantitative measurement of leakage easily. As it is a newly developed device to measure apical leakage of endodontic sealers, the reliability of it needed to be tested.

Bismuth↗

PubMed1996

Assessing apical deformation and transportation following the use of LightSpeed root-canal instruments.

The LightSpeed root canal instrument is similar in design to the Canal Master instrument with the exception of being engine driven and fabricated from nickel-titanium alloy. The purpose of the design of these instruments is to reduce apical transportation of the canal during cleansing and shaping procedures. Twenty extracted human molar teeth with roots of varying degrees of curvature were used in this study. A double exposure radiographic technique was used to assess the presence or absence of apical transportation resulting between the initial instrument and the final instrument, a size 50 LightSpeed. Only one of the 20 teeth examined exhibited apical transportation. Results of this study suggest that little or no apical canal transportation could be expected when curved canals are instrumented using the LightSpeed root canal instruments.

Dental Instruments↗

PubMed1996

Root-end cavity preparation using the MicroMega Sonic Retro-prep Tip. SEM analysis.

The objective of this laboratory study was to compare root-end cavities prepared with sonic Retro-prep tips in a MM1500 Sonic Air handpiece with those created by burs in a conventional handpiece. A total of 80 single-rooted extracted human teeth with mature apices and straight canals were included in the study. Four groups of 20 extracted teeth were prepared as follows: I, a 3-4 mm root-end resection perpendicular to the long axis of the root, with a size 40 sonic Retro-prep tip creating an apical cavity 3 mm into root canal system; II, a 45 degrees bevel of the root-face removing a 3-4 mm root segment and root-end preparation as per group I; III, root-end resection as per group I, with an apical cavity prepared using a size 010 inverted cone bur 3 mm down the long axis of the root; IV, resection as per group II, followed by an apical cavity preparation with a size 010 inverted cone bur 3 mm into the root canal system. The apical root portion and root-end cavities were replicated and prepared for SEM analysis at x 20 and x 80 magnification. The degree of chipping associated with the margin of the root-end cavities, as evaluated with a standard grading system, and the incidence of root-face cracks were noted. Marginal chipping of root-end cavities prepared using sonic instrumentation was significantly worse than that produced by burs (P < 0.001). Perpendicular root-end resections showed significantly better scores than bevelled root-end resections (P < 0.005). The incidence of root-face cracking was low with no significant difference between the experimental groups.

Dental Instruments↗

PubMed1996

The sealing ability of Thermafil obturators assessed by four different microleakage techniques.

An in vitro investigation was performed to assess the extent of apical dye leakage in relation to root fillings made by Thermafil obturators and the lateral condensation of gutta-percha in extracted human teeth under conditions of passive dye penetration, centrifugation, a vacuum technique and an increased air pressure technique. One hundred and twenty-eight extracted teeth were selected and prepared. The specimens were allocated into eight closely matched experimental groups. Four groups were obturated with Thermafil obturators and four with the lateral condensation technique. Microleakage was assessed after exposing one group of specimens from each of the obturation techniques to each of the four dye penetration systems using India ink as the leakage detector. The teeth were demineralized and cleared prior to examination and the maximum dye penetration for each specimen was recorded. The statistical analysis on transformed data revealed no significant differences between the four microleakage techniques and no differences between the two obturation techniques.

Analysis of Variance↗