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At least 1,513 records · Page 84Linked to original sources
PubMed2005

SEM observations of nickel-titanium rotary endodontic instruments that fractured during clinical Use.

Numerous discarded ProFile GT, ProFile, and ProTaper nickel-titanium rotary instruments obtained from two graduate endodontic clinics were examined by scanning electron microscopy. These instruments had an unknown history of clinical use and had fractured or experienced considerable permanent torsional deformation without complete separation. The failure processes generally exhibited substantial ductile character, evidenced by a dimpled rupture fracture surface. Crack propagation at grain boundaries and cleavage surfaces indicative of transgranular fracture were observed for some specimens. It appeared that oxide particles from the manufacturing process served as nucleating sites for the microvoids, leading to dimpled rupture. A previously unreported fracture mode also was observed, in which crack propagation, approximately parallel to the local flute orientation, connected pitted regions on the surface. Combining present and previous scanning electron microscopy observations of clinically failed instruments, suggestions are offered for improving their fracture resistance.

Dental Alloys↗
PubMed2004

Levels of evidence for the outcome of endodontic retreatment.

The purpose of this investigation was 2-fold: (a) to complete a thorough search of published literature related to clinical studies on the success and failure of nonsurgical retreatment, and (b) to assign levels of evidence to these publications. Clinical studies related to success and failure of retreatment since 1970 were identified using both electronic and manual literature searches. After identification of pertinent literature, each article received a level of evidence (LOE) from one (high) to five (low). Thirty-one clinical studies and six review articles related to this subject were identified. There was no LOE 1 Randomized Control Trials (RCT). There were three LOE 2 RCTs, one LOE 2 Cohort, and two LOE 3 Case Control Studies. Thirteen Case Series (LOE 4), which comprise the most highly quoted success and failure data, were found. Twelve Case Reports (LOE 5) and six review articles (LOE 5) were found. Based on these findings, it appears that few high level studies have been published in the past 34 yr related to the success and failure of endodontic retreatment.

Dental Restoration Failure↗
PubMed2005

Endodontic management of dens evaginatus of maxillary central incisors: a rare case report.

Dens evaginatus is a disturbance in tooth development that produces a tubercle of hard tissue on the surface of the tooth. While prophylactic pulp capping is recommended for vital teeth, teeth with necrotic pulps require endodontic therapy or extraction. This rare case of a 24-yr-old Indian male with affected maxillary central incisors demonstrates the clinical consequences of dens evaginatus.

Adult↗
PubMed2005

A 5 yr clinical investigation of second mesiobuccal canals in endodontically treated and retreated maxillary molars.

An examination of 5616 endodontically treated and retreated maxillary first and second molars was made in an attempt to determine the percentage of MB2 canals that could be located routinely, and evaluate if there were any significant differences between initial treatments and retreatments. The teeth examined were 3578 first molars and 2038 second molars treated consecutively over a 5-yr period by six endodontists. Overall the MB2 canal was found in 2133 (60%) first molars, and 712 (35%) second molars. The incidence of a MB2 canal in first molar retreatments was 66% compared to a 58% incidence in initial treatments. Whereas in second molars the retreatment incidence was 40% compared to 34% in initial treatments. The significant difference in the incidence of a MB2 canal between initial treatments and retreatments suggests that failure to find and treat existing MB2 canals will decrease the long-term prognosis.

Chi-Square Distribution↗
PubMed2005

The susceptibility of starved, stationary phase, and growing cells of Enterococcus faecalis to endodontic medicaments.

The purpose of this investigation was to compare the susceptibility of cells of Enterococcus faecalis during exponential growth, stationary phase and starvation phase to three endodontic medicaments. E. faecalis strains VP3-80 and A197A in different growth phases were exposed to saturated calcium hydroxide solution, 0.05% chlorhexidine digluconate and 0.0001% sodium hypochlorite. Cells in the exponential growth phase were the most sensitive to all three medicaments and were killed between 3 s and 10 min. Cells in stationary phase were more resistant and living cells could be recovered at 10 min. However, cells in starvation phase were the most resistant and were not totally eliminated by the medicaments during the 10-min test period. Number of surviving cells of E. faecalis cells to the tested medicaments increased 1000- to 10,000-folds in aging cultures.

Calcium Hydroxide↗
PubMed2005

The effect of endodontic solutions on resorcinol-formalin paste in teeth.

This study determined if any of six endodontic solutions would have a softening effect on resorcinol-formalin paste in extracted teeth, and if there were any differences in the solvent action between these solutions. Forty-nine single-rooted extracted teeth were decoronated 2 mm coronal to the CEJ, and the roots sectioned apically to a standard length of 15 mm. Canals were prepared to a 12 mm WL and a uniform size with a #7 Parapost drill. Teeth were then mounted in a cylinder ring with acrylic. The resorcinol-formalin mixture was placed into the canals and was allowed to set for 60 days in a humidor. The solutions tested were 0.9% sodium chloride, 5.25% sodium hypochlorite, chloroform, Endosolv R (Endosolv R), 3% hydrogen peroxide, and 70% isopropyl alcohol. Seven samples per solution were tested and seven samples using water served as controls. One drop of the solution was placed over the set mixture in the canal, and the depth of penetration of a 1.5-mm probe was measured at 2, 5, 10, and 20 min using a dial micrometer gauge. A repeated-measures ANOVA showed a difference in penetration between the solutions at 10 min (p = 0.04) and at 20 min (p = 0.0004). At 20 min, Endosolv R, had significantly greater penetration than 5.25% sodium hypochlorite (p = 0.0033) and chloroform (p = 0.0018); however, it was not significantly better than the control (p = 0.0812). Although Endosolv R, had statistically superior probe penetration at 20 min, the softening effect could not be detected clinically at this time.

2-Propanol↗
PubMed2005

Comparison of the antimicrobial activity of six irrigants on primary endodontic pathogens.

The purpose of this study was to compare the antimicrobial activities of 6% and 3% sodium hypochlorite (NaOCl), 2% and 0.12% chlorhexidine gluconate (CHX), and 0.01% and 0.005% doxycycline (Doxy) on four microorganisms associated with primary endodontic infections. The agar diffusion test was used to measure antimicrobial activities of these agents against Peptostreptococcus micros, Prevotella intermedia, Streptococcus sanguis, and Lactobacillus acidophilus. Minimum inhibitory concentration analysis was performed using the macrodilution method. For three of the four microorganisms, the general order of antimicrobial effectiveness was 0.01% Doxy >0.005% Doxy >6% NaOCl >3% NaOCl >2% CHX > 0.12% CHX. For L. acidophilus, the order of effectiveness was 6% NaOCl >3% NaOCl >2% CHX > 0.01% Doxy >0.005% Doxy >0.12% CHX. The 6% NaOCl showed significantly greater zones of inhibition than 3% NaOCl for all endopathogens tested.

Analysis of Variance↗
PubMed2005

Reducing surface tension in endodontic chelator solutions has no effect on their ability to remove calcium from instrumented root canals.

The aim of this study was to evaluate the effect of reducing surface tension in endodontic chelator solutions on their ability to remove calcium from instrumented root canals. Aqueous solutions containing 15.5% EDTA, 10% citric acid, or 18% 1- hydroxyethylidene-1, 1-bisphosphonate (HEBP) were prepared with and without 1% (wt/wt) polysorbate (Tween) 80 and 9% propylene glycol. Surface tension in these solutions was measured using the Wilhelmy method. Sixty-four extracted, single-rooted human teeth of similar length were instrumented and irrigated with a 1% sodium hypochlorite solution and then randomly assigned (n = 8 per group) to receive a final one-minute rinse with 5 ml of test solutions, water, or the pure aqueous Tween/propylene glycol solution. Calcium concentration in eluates was measured using atomic absorption spectrometry. Incorporation of wetting agents resulted in a reduction of surface tension values by approximately 50% in all tested solutions. However, none of the solutions with reduced surface tension chelated more calcium from canals than their pure counterparts (p > 0.05).

Analysis of Variance↗
PubMed2005

An in vitro evaluation of the cytotoxicity of various endodontic irrigants on human gingival fibroblasts.

The purpose of this study was to measure the cytotoxicity of six endodontic irrigants on cultured gingival fibroblasts using the CyQuant assay. Human gingival fibroblasts were grown in Dulbecco's Modified Eagle Medium (DMEM) containing 10% fetal bovine serum at 37 degrees C and 5% CO(2). At confluence, cells were split, plated in 96-well plates and incubated for 24-h to allow attachment. The following irrigants were tested at various concentrations: Sodium hypochlorite (NaOCl); iodine potassium-iodide (IKI); Betadine scrub (BS); calcium hydroxide [Ca(OH)2]; chlorine dioxide (SCD) and DMEM (positive control). Experimental groups were compared by the logarithmic difference between the clinical and LD50 concentrations of a particular irrigant. The results showed that IKI and Ca(OH)2 were significantly less cytotoxic than SCD, NaOCl, and BS. In conclusion, IKI and Ca(OH)2 are well tolerated by human gingival fibroblasts.

Analysis of Variance↗
PubMed2005

A novel method for creating endodontic access preparations through all-ceramic restorations: air abrasion and its effect relative to diamond and carbide bur use.

Access through porcelain restorations is a technically delicate and stressful procedure. Although this is a common dilemma in endodontics, little research has explored alternatives in cutting through porcelain. The purpose of this study was to compare the use of a carbide bur plus water, diamond bur plus water, and air abrasion to access through porcelain. All-ceramic samples were accessed using the different techniques. Samples were evaluated using two transillumination methods, white light, and fluorescent liquid penetrant described by the American Society for Testing and Materials. Edge chipping, microcracking, and catastrophic fracture of porcelain caused by the techniques were statistically compared. Fluorescent liquid penetrant was a more sensitive method for microcrack detection. There were significant differences between the preparation techniques. Air abrasion was significantly less destructive, and caused no catastrophic fractures, edge chipping or microcracks. Preparation by air abrasion took longer to complete.

Air Abrasion, Dental↗
PubMed2005

The impact of instrument fracture on outcome of endodontic treatment.

Adoption of rotary nickel-titanium instruments has renewed concerns regarding instrument fracture and its consequences. The frequency of instrument fracture and its impact on treatment outcome were determined from an analysis of specialist endodontic practice records involving 8460 cases. A case-control study of treatment outcomes was conducted on a subset of 146 teeth with a retained instrument fragment (plus 146 matched controls), for which clinical and radiographic follow-up of at least 1 year was available. Masked radiographs were assessed by two calibrated examiners. Overall prevalence of retained fractured instruments was 3.3% of treated teeth. In the case-control study, overall healing rates were 91.8% for cases with a fractured instrument and 94.5% for matched controls (p > 0.05, Fisher's exact test). Healing in both groups was lower in teeth with a preoperative periapical radiolucency (86.7% versus 92.9%, p > 0.05). In the hands of skilled endodontists prognosis was not significantly affected by the presence of a retained fractured instrument.

Case-Control Studies↗
PubMed2005

A comparison of the machining efficiency of two brands of stainless steel endodontic hand files.

The purpose of this study was to compare the machining efficiency of a flexible stainless steel K-type hand file recently introduced by Brasseler USA ("F-Style files"), with that of a well-studied Endodontic instrument ("Flex-o-files," Maillefer Dentsply), that has been on the market for more than 20 years. The comparison of machining efficiencies of these two brands of files was conducted on both dentin and plexiglas substrates, using an apparatus that allowed a constant force to be applied from each file being tested. The results indicated that the Brasseler instruments had poorer machining efficiency than those of the Maillefer files.

Dental Alloys↗
PubMed2005

Endodontic treatment of a large cyst-like periradicular lesion using a combination of antibiotic drugs: a case report.

This case report describes the endodontic treatment of a large cyst-like periradicular lesion using a combination of antibiotic drugs. A 15-yr-old boy with a large cyst-like lesion from the apices of his teeth 29 to 31. Conservative root canal treatment was performed (tooth #30). During treatment procedure, 2.5% sodium hypochlorite solution was used for irrigation and a combination of antibiotic drugs was used for the intracanal dressing. Periapical healing was observed 3-month after initial treatment and continued at the 7-month review.

Adolescent↗
PubMed2005

The application of tissue engineering to regeneration of pulp and dentin in endodontics.

Caries, pulpitis, and apical periodontitis increase health care costs and attendant loss of economic productivity. They ultimately result in premature tooth loss and therefore diminishing the quality of life. Advances in vital pulp therapy with pulp stem/progenitor cells might give impetus to regenerate dentin-pulp complex without the removal of the whole pulp. Tissue engineering is the science of design and manufacture of new tissues to replace lost parts because of diseases including cancer and trauma. The three key ingredients for tissue engineering are signals for morphogenesis, stem cells for responding to morphogens and the scaffold of extracellular matrix. In preclinical studies cell therapy and gene therapy have been developed for many tissues and organs such as bone, heart, liver, and kidney as a means of delivering growth factors, cytokines, or morphogens with stem/progenitor cells in a scaffold to the sites of tissue injury to accelerate and/or induce a natural biological regeneration. The pulp tissue contains stem/progenitor cells that potentially differentiate into odontoblasts in response to bone morphogenetic proteins (BMPs). There are two strategies to regenerate dentin. First, is in vivo therapy, where BMP proteins or BMP genes are directly applied to the exposed or amputated pulp. Second is ex vivo therapy and consists of isolation of stem/progenitor cells from pulp tissue, differentiation into odontoblasts with recombinant BMPs or BMP genes and finally transplanted autogenously to regenerate dentin. This review is focused on the recent progress in this area and discusses the barriers and challenges for clinical utility in endodontics.

Animals↗
PubMed2004

Endodontic treatment of dens invaginatus type III with three root canals and open apical foramen.

AIM: To describe the conservative endodontic treatment and the 1-year follow-up of a permanent maxillary lateral incisor with dens invaginatus. SUMMARY: Frequently, the root canal treatment of invaginated teeth is challenging because of problems associated with gaining access to the root canals and with variations of canal morphology associated with this type of malformation. The present case describes the complex root canal treatment of dens invaginatus in a maxillary lateral incisor with three root canals (Oehler type III), incomplete apex formation, necrotic pulp and abscess formation. After gaining access to two root canals and the invagination with the help of a dental operating-microscope, the canals and the invagination were instrumented and calcium hydroxide dressing was applied for 6 months. Apexification and osseous bone repair were achieved, and the canals were filled with gutta-percha. A follow-up after 1 year showed that the tooth was free of any clinical symptoms and the periapical condition was normal. KEY LEARNING POINTS: The present case demonstrated that conservative root canal treatment can be performed successfully even in sever cases of dens invaginatus. The use of a dental operating microscope can help in the management of complicated cases of invaginated teeth through conventional root canal treatment.

Child↗
PubMed2004

Toxicity of concentrated sodium hypochlorite used as an endodontic irrigant.

AIM: To present a clinical case that illustrates the toxicity of concentrated sodium hypochlorite (NaOCl) on vital tissues. SUMMARY: The severe clinical consequences of extruding concentrated NaOCl into the periradicular tissues during root canal irrigation are described. After diagnosis of external resorption in tooth 34, endodontic treatment was initiated. Following irrigation with a concentrated NaOCl solution, a rapidly developing swelling and haematoma were visible. During the next few days, an extensive bruise and local necrosis of the oral mucosa developed. After healing of the involved tissues, the canal was prepared and obturated. At this time, no clinical symptoms remained. KEY LEARNING POINTS: * The use of concentrated NaOCl as a root canal irrigant might cause severe clinical problems when extruded into vital tissues. * The present report confirms the known toxicity of NaOCl to soft tissues following inadvertent extrusion. * To avoid extrusion, it is always prudent to confirm the length and integrity of the root canal system before irrigating with concentrated solutions.

Dental Pulp Cavity↗
PubMed1989

Oscillatory pattern of sonically powered endodontic files.

When operated in air, the sonic endodontic instrument produced a movement at the driver head which resulted in a large elliptical oscillation of the file. This motion had similar properties to ultrasonically operated files in that there was a distinct variability in the magnitude of the vibratory motion between files of different design, length and thickness. When the sonic file was loaded, the elliptical motion was eliminated leaving a pure longitudinal file oscillation. This mode of vibration was particularly efficient as it was largely unaffected by loading, with the displacement amplitude being similar for different types of file used. The oscillatory pattern of the sonic file may offer a useful mode of mechanically assisted root canal preparation.

Root Canal Therapy↗