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At least 685 records · Page 38Linked to original sources

PubMed2000

Leakage along apical root fillings in curved root canals. Part I: effects of apical transportation on seal of root fillings.

Occurrence of apical transportation (AT) may complicate the root filling procedure and result in a compromised seal. In part I of this study, human mandibular premolars with single, curved (21 to 39 degrees), or straight canals were prepared by Lightspeed or a step-back hand filing technique. An AT index was determined using a double exposure radiographic technique. The prepared canals were obturated using lateral condensation of gutta-percha. Leakage along the apical 3 mm of root filling was measured with a fluid transport model. After hand filing, AT and perforation occurred in 87% of the curved canals. The AT indices were > or = 0.4 mm. After Lightspeed preparation, AT occurred in only 19% of the curved canals. The hand filing/curved group leaked statistically significantly more than the hand filing/straight and Lightspeed/curved groups (p = 0.002). We conclude that occurrence of AT is a factor that negatively influences the apical seal when curved canals are obturated by lateral condensation of gutta-percha.

Bicuspid↗

PubMed2000

Retrograde seal in ultrasonically prepared canals.

The sealing ability of various retrofilling materials was compared. The root canals of 85 single-rooted teeth were cleansed and obturated with gutta-percha without sealer using lateral condensation. The apical 3 mm of the roots were resected and divided into positive control, negative control, and five experimental groups. The experimental teeth received root-end cavity preparation to 3 mm depth using an ultrasonic retroprep tip. The retrocavities were dried and divided into five groups to receive the following materials: amalgam with varnish, amalgam with Clearfil Liner Bond II, thermoplasticized gutta-percha (TGP) with sealer, Ketac-fil, and Super-EBA. After immersion in India ink for 7 days, the roots were demineralized, cleared, and evaluated for dye leakage under a stereomicroscope. Statistical analysis showed that Super-EBA, Ketac-fil, and TGP with sealer demonstrated less leakage than amalgam with varnish and amalgam with Clearfil Liner Bond II (p < 0.05). Super-EBA also leaked significantly less than Ketac-fil or TGP sealer (p < 0.05). No significant difference was found between Ketac-fil and TGP or between the two groups filled with amalgam (p > 0.05).

Dental Amalgam↗

PubMed2000

A comparative scanning electron microscopic investigation of the efficacy of manual and automated instrumentation of root canals.

The cleaning effectiveness of automated and manual root canal instrumentation was investigated with the aid of a scanning electron microscope. Hand instrumentation was performed with K-Flexofiles used in a reaming working motion and according to the step-back technique and with Hedstrom files used in a filing motion. Automated preparation was performed with the KaVo-Endo Flash device featuring torque-limited rotation using K-Flexofiles, as well as with the mechanical ProFile system using rotary nickel-titanium instruments. Twelve teeth each with either straight or curved root canals were instrumented to size 40. After cracking the roots longitudinally (n = 120), the amount of debris and smear layer were quantified on the basis of a numerical evaluation scale (1 through 5). Comparison of manual instrumentation with the automated KaVo-Endo Flash resulted in an equivalent degree of canal cleaning. Complete cleanliness was not achieved by any of the techniques and devices investigated. Best instrumentation results, especially in curved canals, were obtained with rotary ProFile instruments.

Automation↗

PubMed2001

Comparing apical preparations of root canals shaped by nickel-titanium rotary instruments and nickel-titanium hand instruments.

This study measured displacement of canal centers in extracted human teeth after preparation by Lightspeed and nickel-titanium K-files. The specimens were divided into two groups (n = 11), after radiographing the roots from the buccolingual and mesiodistal planes with pathfinding files in situ. More strongly and less strongly curved canals were, respectively, assigned to the Lightspeed and nickel-titanium K-file groups. Using a reassembly technique, cross-sections at 1.25 mm, 3.25 mm, and 5.25 mm from the apices were made of the experimental roots embedded in clear plastic. Stereomicroscopic 35-mm slides were taken of the uninstrumented sectioned canals. The sections were reassembled and then prepared to size 50 Master Apical Rotary and size 40 Master Apical Files, for the Lightspeed and K-file groups, respectively. Similar 35-mm slides of the instrumented canals were taken and electronically superimposed over their uninstrumented counterparts. Displacements of root canal centers after preparation and increases in cross-sectional areas of the prepared root canals were evaluated at specific levels. No significant differences in displacement of canal centers or between the mean cross-sectional areas of the instrumented root canals were recorded between the Lightspeed and K-file groups. Both types of instruments produced similar displacement of canal centers after preparation.

Anatomy, Cross-Sectional↗

PubMed2001

Lack of correlation among three methods for evaluation of apical leakage.

The purpose of this study was to compare three methods of evaluation of the apical seal. Thirty-six teeth were prepared with a ProFile device and filled according to three filling methods: Thermafil (n = 12), warm vertical condensation (n = 12), and the single cone technique (n = 2). The apical seal was recorded with three methods, each successively used on the same teeth: a fluid filtration method, an electrochemical method, and a dye penetration study. The three methods of evaluation did not rank the apical leakage of the three filling techniques in the same order. The fluid filtration method showed that the vertical condensation was superior to Thermafil, which was in turn superior to the single cone technique (p = 0.04). The dye penetration study showed that the Thermafil was a better technique than the vertical condensation and the single cone technique (p = 0.005). The electrochemical method showed no statistical difference among the three filling techniques. No correlation was found among the results obtained with the three methods of evaluation. This study shows that several studies are necessary before comparing the apical seal obtained with various filling techniques.

Analysis of Variance↗

PubMed2001

Effect of removal of the smear layer on apical microleakage.

It has been shown previously that the smear layer created during instrumentation of the root canal promotes apical microleakage. The purpose of the present study was to investigate the effect of removal of the smear layer on apical microleakage, using the fluid filtration method. Thirty-six single-rooted human premolar teeth were used. Six of the teeth were selected randomly as controls, and the remaining 30 teeth were randomly divided into two groups of 15 teeth each. For the first group (group 1) teeth were irrigated with NaOCl only (smear layer not removed). In the second group (group 2) the teeth were irrigated with 15% EDTA, followed by NaOCl to remove the smear layer. Both groups were filled with thermoplasticized gutta-percha (Obtura II) using glass-ionomer cement as sealer. All teeth were stored at 37 degrees C and 100% humidity for 2 days. Apical microleakage of the filled root canal was measured by the fluid filtration technique. Hydraulic conductance was measured by the movement of an air bubble in a capillary tube after a pressure of 200 mm Hg was applied to the system. The mean microleakage rate of group 1 and group 2 were 13.0 (SD +/- 5.1) and 16.9 (SD +/- 15.3) nl/s, respectively. Removal of the smear layer caused significantly more apical microleakage (p < 0.05, Student's t test) than when the smear layer was left intact.

Bicuspid↗

PubMed2001

Effect of apical trephination on postoperative pain and swelling in symptomatic necrotic teeth.

The purpose of this prospective, randomized, blinded study was to determine the effect of apical trephination on postoperative pain and swelling in symptomatic necrotic teeth. Fifty emergency patients participated, and each had a clinical diagnosis of a symptomatic necrotic tooth with associated periapical radiolucency. After endodontic treatment, patients randomly received either an apical trephination or mock trephination procedure. The trephination procedure used a Stabident perforator to provide an initial opening in the cortical bone that was enlarged with files (#25 through #120) and an endodontic spoon. Postoperatively, each patient received: ibuprofen; acetaminophen with codeine (30 mg); and a 7-day diary to record pain, percussion pain, swelling, and number and type of pain medication taken. Results demonstrated the use of an apical trephination procedure did not significantly (p > 0.05) reduce pain, percussion pain, swelling, or number of ibuprofen tablets taken in symptomatic necrotic teeth with periapical radiolucencies. The trephination procedure did significantly (p < 0.05) reduce the use of acetaminophen with codeine overall for the 7 days. In conclusion, because there was not a significant reduction in pain, percussion pain, or swelling we cannot recommend the routine use of an apical trephination procedure, as used in this study, in symptomatic necrotic teeth with radiolucencies.

Acetaminophen↗

PubMed2001

A comparison of apical sealing and extrusion between Thermafil and lateral condensation techniques.

Forty curved canals from 20 mesial roots of extracted human mandibular molars were instrumented (Profile .04) using a crown-down technique and divided into two groups. The experimental group was obturated using the Thermafil technique and the control group was obturated using the lateral condensation technique. Topseal sealer was used in both groups. Apical extrusion was recorded. Two molars were used as control teeth. All specimens were stored in 100% humidity for 1 wk, coated with nail polish, except for the apical 2 mm, and were suspended in black India ink for 48 h. Molars were decalcified, rendered transparent, and linear dye penetration was measured. Linear dye leakage and apical extrusion between the techniques were not statistically different (Mann-Whitney U test).

Carbon↗

PubMed2001

The effect of maintaining apical patency on periapical extrusion.

Thirty-three human maxillary incisors were secured in the openings of a glass vial. Root canals were instrumented to the apical constriction with a step-back technique and a patency file was not used throughout the root canal preparation. The irrigant, 1% NaOCl, was delivered by means of a plastic syringe with a 23-gauge needle and the overflow was suctioned with an aspirator. The total volume of irrigant used was 10 ml. Apically extruded debris and NaOCl were measured. The apical constriction was then deliberately enlarged. With a step-back technique a new 'apical constriction' was created, coronally to the original one. A patency file was again not used, and irrigation was identical to the that used during the initial root canal preparation. Extruded debris and NaOCl in each bottle were again measured. Results indicated that there was significant difference in the amounts of extruded material before and after the enlargement of the apical constriction with greater extrusion when the constriction remained intact.

Anti-Infective Agents, Local↗

PubMed2001

Effect on the healing of periapical perforations in dogs of the addition of growth factors to calcium hydroxide.

The purpose of this study was to investigate the effect of the addition of platelet-derived growth factor-BB and insulin-like growth factor-I to calcium hydroxide in the repair of apical perforations in dogs. Fifty-one premolar teeth of four beagle dogs were used. After developing periapical lesions root apices were artificially perforated. The teeth were divided into the three groups: group 1, the apical perforations were not sealed; group 2, the perforated areas were obturated with calcium hydroxide; and group 3, calcium hydroxide plus growth factors was applied to the sites of perforation. All canals were filled by a lateral condensation technique. Animals were killed 12 wk later, and sections were hematoxylin & eosin-stained and immunostained for osteonectin. The amount of inflammation was evaluated histomorphologically. The one-way ANOVA test demonstrated that the three groups were significantly different from one another. In group 3 there was no inflammatory reaction of apical tissue, and the connective tissue adjacent to the newly formed hard tissue was strongly immunostained for osteonectin. Most sections in group 1 showed no apical healing. Moderate healing was found in group 2. In conclusion the combination of platelet-derived growth factor-BB and insulin-like growth factor-I with calcium hydroxide improved healing of apical perforation in dogs.

Alveolar Bone Loss↗

PubMed2002

Apexification: an interesting case.

This case of total pulpal necrosis and infection illustrates a relatively unexpected apexification outcome that morphologically closely resembled normal root end formation.

Calcification, Physiologic↗

PubMed2002

Hemostatic efficacy and cardiovascular effects of agents used during endodontic surgery.

The hemostatic efficacy, as well as the cardiovascular effects, of two hemostatic agents currently used during endodontic surgery was examined. The hemostatic agents used were epinephrine pellets (Racellet pellets) or 20% ferric sulfate (Viscostat). Patients were assigned to one of two experimental groups. Blood pressure and pulse rate were recorded pre- and postoperatively and at three additional times during the surgery (root-end resection, root-end preparation, and filling). The adequacy of hemostasis was rated by the surgical operator. Results indicated that there is no significant change in cardiovascular effects when using either of these hemostatic agents. Except in one case where ferric sulfate was the agent, both agents produced surgical hemostasis that allowed for a dry field for root-end filling.

Administration, Topical↗

PubMed2002

Apical leakage of five root canal sealers after one year of storage.

A fluid transport model study was used to compare the sealing ability of five root canal sealers (AH26, AH Plus, Apexit, Diaket, and Ketac-Endo) on 60 single-rooted teeth after 1 yr of storage. The root canals were prepared with Gates Glidden drills by using a step-back technique before lateral condensation of gutta-percha with the tested sealers. The specimens were stored in saline solution for 1 yr at 37 degrees C. The leakage was measured by the movement of an air bubble in a capillary glass tube connected to the experimental root section. Apexit (0.490 microl) leaked significantly more than AH Plus (0.378 microl) and Ketac-Endo (0.357 microl), whereas AH26 (0.390 microl) and Diaket (0.429 microl) showed no significant difference from either Apexit or from AH Plus and Keto-Endo.

Bismuth↗

PubMed2002

Effect of three different sealers on the sealing ability of both thermafil obturators and cold laterally compacted Gutta-Percha.

The purpose of this study was to assess the seal obtained in straight and curved root canals filled with either laterally compacted gutta-percha or Thermafil obturators. Each technique was used in combination with three different sealers (RSA RoekoSeal, AH Plus, AH 26). Thermafil obturators were also used without sealer, resulting in a total of 14 test groups of 16 teeth each. Sixty teeth served as positive or negative controls. Included in the study were 142 extracted teeth with straight and 142 with curved root canals. All canals were enlarged up to size 40. After obturation, all roots were placed in India ink for 48 h and rendered transparent to measure the maximum linear dye penetration. Canals filled with Thermafil obturators had significantly more extrusion of filling material than canals filled by lateral compaction (p < 0.01). Thermafil without sealer showed significantly greater dye penetration compared with all other groups both in straight and in curved canals (p < 0.05). As long as a sealer was used, the seal obturated with Thermafil was equivalent in terms of dye penetration to lateral compaction. There were no statistical differences in the mean apical dye penetration among the three sealers. The differences between the dye penetration in straight and in curved canals were insignificant for all groups (p > 0.05). Under the conditions of this study, Thermafil obturators achieved seals comparable to lateral compaction, as long as a sealer was used.

Analysis of Variance↗

PubMed2002

Effect of sonic and ultrasonic retrograde cavity preparation on the integrity of root apices of freshly extracted human teeth: scanning electron microscopy analysis.

Sonic and ultrasonic root-end preparation devices permit the preparation of conservative and straight cavities. However, microfractures and marginal chipping can occur due to the vibratory action of such instruments. The purpose of this study was to evaluate the effect of retrograde preparations by using sonic and ultrasonic tips on the integrity of root-end surfaces. Eighty, human anterior teeth were grouped according to size and treated as follows: treatment 1: root-end resection (RR) and root-end cavity preparation (RP) with KIS ultrasonic retrotip; treatment 2: RR and RP with Satelec S12/90 (no diamond coating) ultrasonic retrotip; treatment 3: RR and RP with a diamond-coated retrotip attached to a sonic device (Sonics); treatment 4: RR and RP with Satelec S12/90D (diamond coated) ultrasonic retrotip. The root-end surface topographies were assayed by means of polyvinylsiloxane impressions and epoxy resin replicas. SEM pictures of each sample were taken before and after preparation, and the images were evaluated by using an image processing and analysis system. The parameters evaluated were shape quality, presence of cracks, and marginal chipping. The results showed no statistically significant differences among anatomic groups, treatments, or tooth sizes (p > 0.05). Because treatment 3 removed more dental structure than the others did, its use on small teeth is inadvisable.

Apicoectomy↗

PubMed2002

The quality of apical canal preparation using hand and rotary instruments with specific criteria for enlargement based on initial apical file size.

The aim of this study was to compare the quality of apical enlargement of mesiobuccal canals of mandibular molars using conventional stainless steel hand files (K files) and nickel-titanium (Ni-Ti) rotary instruments (LightSpeed). Thirty freshly extracted mandibular molars were randomly assigned to three equal groups (n = 10 each group). The mesiobuccal canals were instrumented with K file using step-back technique without coronal flaring (control; group 1), K file using step-back technique after coronal flaring (group 2), and LightSpeed instrumentation (group 3). Specific criteria for apical enlargement based on initial apical size were used. For step-back techniques, the master apical file sizes were based on the Grossman criterion of three sizes larger than the first file that bound at working length, without coronal flaring (group 1) and with flaring (group 2). For the LightSpeed (LS) group, the master apical rotary sizes were based on the manufacturer's recommendation. Canal cleanliness, canal transportation, and final canal shapes were determined histologically at 1-mm and 3-mm levels short of the working length. Canals were prepared to significantly larger sizes using LS instrumentation than with either hand instrumentation techniques (15-17 ISO units, p < 0.001). LS instrumentation allowed greater apical enlargement with significantly cleaner canals, less apical transportation, and better canal shape than both hand instrumentation groups at both levels (p < 0.05). None of the three techniques was totally effective in cleaning the apical canal space. It was concluded that greater apical enlargement using LS rotary instruments is beneficial as an attempt to further debride the apical third region in mesiobuccal canals of mandibular molars. Instrument designs, alloy properties, and canal curvature are important factors that determine the feasibility of greater apical enlargement in narrow canals.

Analysis of Variance↗

PubMed2002

Radiographic evaluation of the effect of endotoxin (LPS) plus calcium hydroxide on apical and periapical tissues of dogs.

The aim of this study was the radiographic evaluation of the apical and periapical region of dog teeth submitted to intracanal bacterial endotoxin (lipopolysaccharide, LPS), associated or not with calcium hydroxide. After removal of the pulp, 60 premolars were divided into four groups and were filled with bacterial endotoxin (group 1), bacterial endotoxin plus calcium hydroxide (group 2), saline solution (group 3), or periapical lesions were induced with no treatment (group 4), for a period of 30 days. Similar periapical lesions were observed in groups 1 and 4. The lamina dura was intact in groups 2 and 3. Bacterial endotoxin (LPS) caused radiographically visible periapical lesions, but when associated with calcium hydroxide, this endotoxin was detoxified.

Animals↗

PubMed2002

Comparison of the apical seal obtained by a dual-cure resin based cement or an epoxy resin sealer with or without the use of an acidic primer.

This study compared the apical leakage of roots obturated with gutta-percha using either a dual-cure resin based cement (Panavia F) or an epoxy-resin sealer (Thermaseal plus) with or without the application of an acidic primer (ED Primer). Eighty-six single rooted canine teeth were decoronated, cleaned, and shaped by using hand and rotary instruments, randomly divided into four groups, and obturated as follows: group A (n = 20): ED Primer applied followed by thermoplastized obturation with gutta-percha and Thermaseal Plus sealer; group B (n = 20): thermoplastized obturation with gutta-percha and Thermaseal Plus; group C (n = 20): ED primer applied followed by thermoplastized obturation with gutta-percha and Panavia F; group D (n = 20): thermoplastized obturation with gutta-percha and Panavia F. Both a negative control (n = 3; entire root coated with wax) and a positive control (n = 3; obturated with only a fitted master cone) were included in the study. Groups A, B, C, D, and the controls were immersed in molten sticky wax, leaving the apical 2-mm exposed, and quickly chilled. All teeth were immersed in 1% methylene blue dye solution for 10 days, rinsed, and sectioned longitudinally. Apical dye penetration was measured stereomicroscopically at 10-fold magnification. The analysis of variance and Duncan Multiple Range were used for result analysis. The specimens obturated with gutta-percha and an epoxy-resin sealer (with or without an acidic primer) demonstrated significantly less linear dye penetration than specimens obturated with gutta-percha and the dual-cure, resin-based cement (with or without an acidic primer).

Analysis of Variance↗