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Results for “Tooth Apex”

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At least 577 records · Page 32Linked to original sources

PubMed2006

A 1-year follow-up study on leakage of single-cone fillings with RoekoRSA sealer.

OBJECTIVE: The aim of this study was to measure long-term leakage along single cone (SC) fillings. STUDY DESIGN: Two groups of canines (n = 30) were prepared and a size 55 file was the apical master file. Step-back was performed using files of sizes 60, 70, and 80. The canals were filled by the single cone technique using RoekoRSA as sealer. To place sealer into each canal, a bidirectional spiral was used in 1 group, whereas a gutta-percha cone was used in the other group. Immediately after root filling, the coronal portion of root filling was removed by postspace preparation. Leakage along the 4 mm remaining apical root filling was measured after 1 week and again after 1 year using a fluid transport model. Ten additional canine roots were prepared and filled with gutta-percha cones without sealer, serving as positive controls. Occurrence of apical extrusion of materials was recorded. RESULTS: The apical root filling in all 60 canine roots did not show leakage either at 1 week or at 1 year. All 10 positive controls showed gross leakage (>20 muL/h). In no case gutta-percha extruded through the apical foramen. Sealer extruded apically in 88% of the roots where a gutta-percha cone was used to introduce sealer, whereas in 28% of the roots where a bidirectional spiral was used to introduce sealer (by chi-square test, P < .05). CONCLUSION: In wide and straight canals, SC fillings with RoekoRSA sealer prevented fluid transport for 1 year. Using bidirectional spiral to place sealer reduced sealer extrusion under the conditions of this experiment.

Cuspid↗

PubMed2005

Epithelium and bacteria in periapical lesions.

OBJECTIVE: The purpose of this study was to evaluate 50 human periapical lesions for bacteria and epithelium in a case study in dental practice. STUDY DESIGN: Specimens were obtained from the extraction of 50 untreated teeth that had lesions attached to their apices. The specimens were histologically evaluated using serial sections. RESULTS: Bacteria were found in all teeth, colonizing necrotic tissue in the main canal, dentinal tubules, or apical ramifications, and in the body of the periapical lesion in 18 abscesses or cysts. Twenty-one lesions were epithelialized; 14 abscesses, 20 granulomas, and 16 cysts were distinguished. In 18 root canals inflamed tissue was found in the apical part of the canal. A single foramen was present in 13 cases while apical ramifications were found in 37 cases. CONCLUSIONS: Granulomas were most common, and most epithelialized lesions were cysts. Bacteria were only detected periapically in abscesses or cysts. Inflamed tissue was present in the apical root canal in one third of cases.

Adolescent↗

PubMed2006

A clinical method to determine the optimal apical preparation size. Part I.

OBJECTIVE: To establish a new approach for determination of the optimal apical preparation size (APS). STUDY DESIGN: After preflaring 212 root canals from 80 extracted molars, electronic working length (WL) was measured to establish where the apical preparation size (APS) should be determined. Subsequently, nontapered, noncutting special instruments were used to reach WL. The diameter of the largest special instrument (SI) width that had to overcome some resistance to advance to WL was defined as d(SI). After sectioning the roots apically, the diameter of a potential rotary instrument was determined for each section, allowing a complete cutting of the root canal wall. The estimation of APS was related to d(SI). RESULTS: Theoretically, individual APS of d(SI) + 0.60 mm yielded circumferential apical preparations in 98% of the cases. When shaping palatal/distal root canals of molars to d(SI) + 0.40 mm, and mesiobuccal/mesiolingual/distobuccal root canals of molars to d(SI) + 0.30 mm, complete preparations of root canal walls resulted in 78% (95% CI, 69%-87%) and 72% (95% CI, 65%-80%) of canals, respectively. CONCLUSION: The described approach allowed evaluation of the APS for most root canals. Root canals should be shaped to larger sizes than normally recommended.

Algorithms↗

PubMed2006

Extended apical enlargement with hand files versus rotary NiTi files. Part II.

OBJECTIVE: The objective of this study was to compare 2 preparation techniques performed under simulated clinical conditions with extended apical enlargement following determination of the optimal apical preparation size (APS). STUDY DESIGN: After preflaring 240 root canals, APS was evaluated as outlined in Part I. The apical portion was shaped to APS either with rotary NiTi Lightspeed instruments (LS) or NiTi hand instruments (HA) using the balanced force technique in a phantom head. After sectioning the apical area at 3 levels, every cross section was analyzed microscopically for circumferential removal of canal wall dentine. Loss of working length, instrument separation, and perforation were additionally recorded. RESULTS: In 70% (LS) and 69% (HA) of the root canals, 2 of 3 levels demonstrated that the root canal dentin was cut circumferentially. Neither loss of working length nor perforation occurred in both groups. Four LS instruments separated. CONCLUSIONS: APS frequently results in a nearly complete apical preparation regardless of the preparation techniques. In a few cases apical enlargement to APS does not achieve complete cutting of the canal walls. There was a rather slight risk of serious procedural errors.

Algorithms↗

PubMed1999

Photoelastic stress analysis of load transfer to implants and natural teeth comparing rigid and semirigid connectors.

STATEMENT OF PROBLEM: Controversy exists regarding the connection of implants to natural teeth. PURPOSE: This simulation study measured photoelastically the biologic behavior of implants. Stress transfer patterns with variable implant support and simulated natural teeth through rigid and nonrigid connection were examined under simulated functional loads. MATERIAL AND METHODS: A photoelastic model of a human left mandible edentulous distal to first premolar was fabricated having 2 screw type implants (3.75x13 mm) embedded within the edentulous area. Two fixed prosthetic restorations were fabricated with either a nonsplinted proximal contact or a soldered proximal contact, and cast precision dowel attachment between implant areas and simulated tooth. Simulated vertical occlusal loads were applied at fixed locations on the restorations. Stresses, which developed in the supporting structure, were monitored photoelastically and recorded photographically. RESULTS: The rigid connector in the 1 implant situation caused only slightly higher stresses in the supporting structure than the nonrigid connector. The distally loaded 1 and 2 implant-supported restoration produced the highest apical stresses, which occurred at the distal implant. The rigid connector demonstrated the greatest stress transfer in the 2 implant-supported restoration. CONCLUSIONS: Lower stresses apical to the tooth or implant occurred with forces applied further from the supporting abutment. Although the least stress was observed when using a nonrigid connector, the rigid connector in particular situations caused only slightly higher stresses in the supporting structure. The rigid connector demonstrated more widespread stress transfer in the 2 implant-supported restoration. Recommendations for selection of connector design should be based on sound clinical periodontal health of a tooth and the support provided by implants.

Adult↗

PubMed1997

Glycoproteins expression in apical pathologic tissues: clinical incidences.

Indirect immunofluorescence was used for the localization of the primary collagens, fibronectin and laminin. Specimens were extracted from untreated teeth with periapical lesions from patients 20 to 30 years of age. An histological examination enabled the differentiation of granulomas and cysts, and 5 microns sections were used for the indirect immunofluorescence procedure. Antibodies against Type I, Type III, and Type V collagen and for fibronectin and laminin were obtained from glycoproteins of human cells. The antibody against Type IV collagen was prepared from Type IV collagen of beef retina. All the glycoproteins investigated were expressed in apical lesions. The intensity of the immunostaining appeared more positive at the external area compared with the center of the lesion. The type IV collagen was specific for the basement membrane of cysts. The immunofluorescence reactions of fibronectin and of laminin were similar in intensity in both granulomas and cysts.

Adult↗

PubMed1975

The effect of preparation procedures on original canal shape and on apical foramen shape.

With the use of clear casting resin, simulated curved canals were created so that canal preparation procedures could be directly visualized and compared. Regardless of the type of enlarging instrument or the technique used, undesirable characteristics were produced in all preparations that would make canal filling difficult. To modify the typical preparations, alteration of the enlarging flutes, use of rasping rather than rotation of the instruments, and a flaring technique are recommended.

Dental Pulp Cavity↗

PubMed1975

A comparative study of apical leakage with endodontic implant stabilizers.

The apical seals of 75 extracted teeth that were treated with three methods of endodontic implant stabilizers were compared with the seals of 25 teeth filled with silver cones and 25 teeth filled with laterally condensed gutta-percha. Apical leakage was measured with the use of methylene blue dye solution. Statistical analysis showed that there were significant differences between the apical leakage obtained from the teeth treated with endodontic implant stabilizers and those teeth filled with silver cones and with laterally condensed gutta-percha.

Dental Implantation, Endosseous, Endodontic↗

PubMed1996

A comparison of pulpectomy alone versus pulpectomy with trephination for the relief of pain.

Patients who when initially seen have pain of endodontic origin have a higher incidence of posttreatment pain than those who are pain-free pretreatment. The purpose of this study was to compare two methods of treatment--pulpectomy alone or pulpectomy with trephination--for the reduction of posttreatment pain in patients presenting with acute periradicular pain of pulpal origin. Seventeen patients with pretreatment pain were studied. Eleven received a pulpectomy to the radiographically determined working length. Six patients received a pulpectomy and trephination using a #4 round bur through a vertical incision. Visual analog scales were used preoperatively to measure pain intensity and unpleasantness, and postoperatively to measure intensity, unpleasantness, and pain relief at 4, 8, 16, 24, 48, 72, and 96 h. Analysis of preoperative data showed no difference between control and experimental groups. Posttreatment, at 4 h, the trephination group reported significantly more pain intensity and unpleasantness and less pain relief than the control group. Pulpectomy alone provided significantly better postoperative pain relief at 4 h compared with pulpectomy with trephination. At no time interval did the trephination group have less pain than the group without trephination.

Decompression, Surgical↗

PubMed1997

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.

Carbon↗

PubMed1997

Linear dye penetration of a calcium phosphate cement apical barrier.

Linear dye penetration was evaluated in teeth with open apices in which calcium phosphate cement was used as an apical barrier to facilitate obturation. The apical foramens of 42 extracted single-rooted human teeth were opened to a size 90 file. Half the teeth received apical barriers consisting of calcium phosphate cement (CPC) followed by obturation using a customized gutta-percha cone/ lateral condensation technique. The other half were obturated without benefit of apical barriers. Linear dye penetration was measured after 48 h exposure to India ink. The teeth receiving apical CPC barriers before obturation had significantly less dye penetration than teeth without apical barriers. Based on its proven biocompatibility and osteconductive potential, calcium phosphate cement may serve well as a replacement for calcium hydroxide in a single-visit immediate apical barrier apexification technique.

Calcium Phosphates↗

PubMed1997

Calcium hydroxide root canal sealers--histopathologic evaluation of apical and periapical repair after endodontic treatment.

Eighty root canals of the premolars of 4 dogs, with vital pulp, were instrumented and filled during the same session with the Sealapex, CRCS, Sealer 26, and Apexit sealers. The animals were sacrificed 180 days after root canal filling and their maxillae and mandibles were removed and fixed in 10% formalin. After routine histologic processing, the sections were stained with hematoxylin-eosin and Mallory trichrome. Histopathologic analysis showed that Sealapex was the sealer that best permitted the deposition of mineralized tissue at the apical level and was the only sealer that provided complete sealing (37.5% of cases). With the use of Sealapex, no inflammatory infiltrate occurred and there was no reabsorption of mineralized tissues. In contrast, partial sealing and a moderate inflammatory infiltrate occurred with the use of CRCS. When Apexit and Sealer 26 were used the absence of sealing was frequent and active reabsorption of mineralized tissues occurred in most cases. The inflammatory infiltrate predominating with the use of Apexit was of the severe type, whereas with the use of Sealer 26 the inflammatory infiltrate was mild or absent.

Animals↗

PubMed1997

Histological evaluation of the effectiveness of five instrumentation techniques for cleaning the apical third of root canals.

The efficacy of five instrumentation techniques for cleaning the apical third of curved root canals was assessed by histological examination. Mesial root canals of freshly extracted human mandibular molars were prepared by the following instrumentation methods: step-back technique using stainless steel files; step-back technique using nickel-titanium files; ultrasonic technique; balanced force technique; and Canal Master U technique and instruments. The apical portion of the root was histologically processed, and cross-sections were examined for remaining soft tissue, predentin, and debris. The results showed no significant differences among the techniques. Although the five instrumentation methods were effective in removal of major amounts of tissue from the canals, none totally debrided the entire root canal system, especially when variations in the internal anatomy were present.

Dental Alloys↗

PubMed1997

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

Thirty extracted human single-root teeth were instrumented to #45 file size while creating a continuous coronal taper. Canals were obturated with Roth 801 sealer and either JS Quick-Fill or lateral condensation of gutta-percha. Mean apical linear microleakage of India Ink was evaluated in cleared teeth using a stereomicroscope. Significantly less leakage (p < 0.1) occurred with lateral condensation than with JS Quick-Fill.

Carbon↗

PubMed1998

Shaping ability of Mity Roto 360 degrees and Naviflex rotary nickel-titanium instruments in simulated root canals. Part 1.

The aim of this study was to determine the shaping ability of Mity Roto 360 degrees and Naviflex nickel-titanium rotary instruments in simulated root canals. In all, 80 canals consisting of four different shapes in terms of angle and position of curvature were prepared by Mity Roto 360 degrees and Naviflex instruments using the techniques recommended by the manufacturers. This study describes the efficacy of the instruments in terms of preparation time, instrument failure, canal blockages, change in canal length, and three-dimensional canal form. Overall, the mean preparation time for canals prepared using Mity instruments was 5.99 min and 5.81 min when using Naviflex instruments. Canal shape had no significant effect on the speed of preparation with either instrument. No instruments separated during the study; however, 14 Naviflex and 2 Mity instruments were deformed. Canal type did not influence significantly the tendency of either instrument to deform. None of the canals became blocked with debris during preparation. The majority of canals prepared by both instruments retained their original working length, and there was no significant difference between the canal shapes in terms of the mean loss of distance or category of distance change for either instrument. Apical stops as judged from intracanal impressions were present in 29 (72%) of the canals prepared with Mity instruments and in 33 (82%) of those prepared with Naviflex instruments. However, the majority were judged to be of poor quality. Significant differences (p < 0.05) were noted in the quality of apical stops between the canal types using Mity instruments. Canals prepared with Mity and Naviflex instruments were found to be smooth in the apical half of the canal in approximately one-half of the specimens and coronally in nearly all canals. Neither instrument produced horizontal or longitudinal grooves. Favorable flow characteristics were apparent in over one-half of the canals prepared with Mity Roto instruments; however, nearly all specimens had poor taper. Flow and taper were generally poor in the specimens prepared with Naviflex instruments. Under the conditions of this study, Mity Roto 360 degrees and Naviflex instruments prepared canals rapidly, with no separations, canal blockages, and with minimal change in working length. Although, flow was adequate using Mity Roto 360 degrees instruments, the taper characteristics were less than ideal compromising the three-dimensional form of the canals. Naviflex instruments, while creating better taper, produced poorer flow characteristics. The results suggest that when using Mity Roto 360 degrees or Naviflex instruments, the stepdown sequence should be modified to improve canal flow and taper. Alternatively, an instrument with increased taper should be used to complete preparation before obturation.

Dental Instruments↗

PubMed1998

Risk assessment of the toxicity of solvents of gutta-percha used in endodontic retreatment.

Three randomly assigned groups of single-canaled extracted teeth obturated with gutta-percha were retreated using controlled application of one of three organic solvents: chloroform, xylene, or halothane. Two additional groups of teeth served as positive and negative controls. Residual volume of solvent expressed through the apical foramen during retreatment was determined by the difference of pretreatment and posttreatment weights of hermetically sealed receptacles attached to the root surface of the teeth. Results indicate that the amount of solvent that has been determined to have leached out through the apical foramen is several orders of magnitude below the permissible toxic dose. Thus, it is proposed that the use of any of the aforementioned solvents used in the retreatment of root canals would pose negligible risk to the patient.

Chloroform↗

PubMed1998

Histopathological study of the use of freeze-dried allogenic dentin powder and True Bone Ceramic as apical barrier materials.

The biocompatibility of freeze-dried allogenic dentin powder and True Bone Ceramics (TBC), the latter prepared by incineration of bovine bone, as apical barrier materials was evaluated histopathologically in dogs. After pulpectomy, 80 root canals of 53 dog premolar teeth were prepared, and each material was tightly packed to the apical stop area. The remainder of the canal was filled with guttapercha by the lateral condensation method. Control teeth were filled by the lateral condensation method using gutta-percha without constructing apical barriers. In both the teeth filled with the dentin powder and those filled with TBC, multinucleate giant cells appeared on the bone resorption surface and the surface of the root canal wall, and marked bone resorption and positive tartrate-resistant acid phosphate staining were observed. Hard tissue had formed on the root canal wall and the filling material after 3 months. These findings suggest that the test materials are nonirritative and compatible with periapical tissue, and that they may be useful and clinically applicable as apical barrier materials.

Animals↗

PubMed1998

Effect of masticatory cycles on apical leakage of obturated teeth.

This study investigated the effect of apical leakage due to masticatory cycles on root canal treatment. Twenty upper maxillary molars were first obturated using the warm vertical compaction technique. Four maxillary casts were then built, with each holding four of the sample molars. The molars were embedded in resin with the roots separated from the resin by means of a light silicon. The four remaining teeth served as controls and were not submitted to occlusal forces. A mechanical device to simulate masticatory cycles subjected the teeth to 0.5 x 10(6) cycles (group A), 10(6) cycles (group B), 2 x 10(6) cycles (group C), and 3 x 10(6) cycles (group D); the control was group E. The roots were placed in 2% methylene blue dye solution for 72 h and then sectioned longitudinally so that dye penetration could be measured. The mean values of dye penetration were: 3.70 +/- 0.69 mm, group A; 5.00 +/- 1.14 mm, group B; 6.00 +/- 1.01 mm, group C; 7.23 +/- 0.66 mm, group D; and 2.74 +/- 0.75 mm, group E. The value of dye penetration increased in correlation with the number of masticatory cycles. This in vitro study suggests the significant effect of masticatory loads on apical leakage.

Bite Force↗