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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↗

[Apical thickness of root fillings in upper premolars. A comparison of orthograde-filled, apicoectomized and retrograde-filled teeth].

The objective of this study was to compare the apical leakage in root canal filled, apicectomised and retrogradely filled maxillary single rooted premolars with two canals of type II configuration. For this purpose the root canals of 51 maxillary type II premolars were shaped to size ISO #55, followed by a step-back preparation to size ISO #80. Subsequently, all teeth were obturated by means of lateral condensation and randomly divided into three groups, 17 teeth each. Group I was used as a control, whereas in group II and III an apicoectomy was performed. Retrograde glass ionomer restorations (Ketac Fil) were placed additionally in group III. The specimens were exposed to methylene blue for 24 hours, then cross-sectioned, and the deepness of dye penetration was measured. Data were analyzed and tested for significant differences between the various groups (Mann-Whitney test; alpha = 0.05). The teeth in group II showed the lowest mean dye penetration. The differences were statistically significant, if compared to group I (p < 0.001) and group III (p < 0.001). The dye penetration in group I was significantly lower than in group III (p = 0.024). In teeth with lateral canals, the mean dye penetration was higher (3,557 microns +/- 1,337 microns) than in teeth without lateral canals (3,096 microns +/- 1,931 microns). The teeth in group III showed a circular dye penetration in nearly all cases. For clinical purposes, the application of retrograde glass ionomer fillings must be considered very critically.

Apicoectomy↗

Comparison of the sealing capabilities of Ketac-silver and extra high copper alloy amalgam when used as retrograde root canal filling.

Apical microleakage following reverse retrograde root filling with extra high copper amalgam alloy was compared with that following a silver-glass ionomer retrofilling. The root canals of 56 extracted, single-rooted anterior human teeth were instrumented and obturated with laterally condensed gutta-percha and zinc oxide-eugenol sealer. Each tooth was apically resected at 45 degrees to its long axis and the root surface isolated with nail varnish. Teeth were divided into three groups. The first group received extra high copper amalgam retrograde fillings, the second group was retrofilled with a silver-glass ionomer, and the control group had no retrograde root filling placed. Following immersion in 1% methylene blue dye at 37 degrees C, the roots were sectioned and dye penetration was measured using an image analyzer. The sealing effectiveness of these materials was determined by their ability to inhibit dye penetration at 24 and 48 h. The results of this study show that a silver glass-ionomer is just as effective as extra high copper amalgam in terms of sealing capability. There was no statistically significant difference between the two materials.

Cermet Cements↗

Cyanoacrylate as a retrofilling material.

The sealing ability of cyanoacrylate as a retrograde root canal filling material was evaluated in vitro. Fifty roots were cleansed, shaped, and assigned to five groups of ten roots each. The root canals were obturated with gutta-percha and Grossman's sealer. The apical 2 mm of each root in the five groups was resected. In groups I, II, and III, retrofilling preparation was made and filled with amalgam, varnish and then amalgam, and cyanoacrylate, respectively. In group IV, a hot instrument was used to seal the gutta-percha, and in group V, a cold burnisher was used for the same purpose. All of the teeth were immersed in 1% methylene blue dye for 24 hours and sectional longitudinally; dye penetration was then measured. One-way analysis of variance performed on the means of the groups indicated that group III had the least amount of leakage (p less than 0.05). This study indicates that cyanocrylate may have potential as a retrograde filling material.

Apicoectomy↗

Biocompatibility of retrograde filling materials in the ferret canine. Amalgam and IRM.

Periapical tissue response to retrograde fillings of amalgam and IRM were compared in the mandibular canine of the adult male ferret. Teeth were cleaned and shaped with a standard technique and obturated with gutta-percha. The root apex was then exposed and retrofillings were placed. The animals were grouped according to observation periods of 5, 10, and 15 weeks. At the proper time the animals were killed and the lower canine tooth along with the surrounding bone was removed. The tissue blocks were examined clinically, radiographed, and prepared for histologic examination. The clinical and radiographic examination indicated both materials to be well tolerated by periapical tissues. Microscopic examination of amalgam specimens showed a decrease in inflammation and the formation of a fibrous capsule over the 15-week period. IRM specimens showed persistent inflammation and slower healing potential.

Alveolar Process↗

Sealing ability of cermet ionomer cement as a retrograde filling material.

An in vitro dye leakage study was performed to compare the sealing ability of high copper amalgam with cavity varnish and cermet ionomer cement with and without varnish when used as retrofilling materials. The root canals of 54 maxillary anterior teeth were instrumented and obturated with gutta-percha and sealer. The apical 3 mm of the roots were resected and apical class I cavity preparations were made. The roots were then randomly divided into three groups and retrofilled with one of the experimental materials. After 72 h of immersion in India ink, the roots were cleared and evaluated for leakage with a stereomicroscope. Statistical analysis indicated that the cermet ionomer cement with varnish group had significantly less leakage than the amalgam group (P < 0.0014) and the cermet ionomer cement without varnish group (P < 0.001). There was no significant difference between the other two groups (P > 0.05).

Cermet Cements↗

Sealing ability of amalgam, super EBA cement, and MTA when used as retrograde filling materials.

OBJECTIVE: To compare apical microleakage of MTA following reverse retrograde root filling with that following amalgam and EBA retrofilling. DESIGN: Prospective random control trial. SETTING: It was conducted at the University of Jordan in 1998. MATERIALS AND METHODS: The root canals of 79 extracted teeth were instrumented and obturated with vertically condensed gutta-percha. Each tooth was apically resected and the apex was prepared ultrasonically to 3 mm depth and the root surface isolated with nail varnish. Teeth were divided randomly into three groups of 25 teeth each. First group was retrofilled with amalgam, second group with EBA and the third group with MTA. Following immersion in 1% methylene blue dye for 72 hours, the roots were sectioned and the depth of dye penetration was evaluated by a stereomicroscope at x10 magnification. INTERVENTIONS: Super EBA is a reinforced zinc oxide cement based on a mixture of 32% eugenol and 68% ethoxy benzoic acid (EBA). MTA is a mineral trioxide aggregate cement (MTA) based on a mixture of sterile water. MAIN OUTCOME MEASURES: The sealing effectiveness of the retrograde filling materials used in this study was determined by their ability to inhibit dye penetration. RESULTS: 56% of the group filled with amalgam and 20% of the group filled with EBA showed dye leakage beyond the retrofilling material whereas the MTA group showed none, two samples from MTA group were eliminated because of their fractured roots. The chi-squared test revealed a statistically significant difference among all three groups (P < 0.05). CONCLUSION: MTA cement provides a better seal than amalgam and EBA cement when used as retrograde filling, but the extrapolation of this result into a clinical practice may be questionable.

Aluminum Compounds↗

Silver glass ionomer cement as a retrograde filling material: a study in vitro.

Comparison was made of the apical microleakage of retrograde fillings with amalgam and with silver glass ionomer cements using a modified dye penetration method. Forty instrumented human teeth were divided into four groups. Each group was characterized by a different retrograde filling material or technique: Group 1--silver glass ionomer (SGI); group 2--SGI with previous acid wash of the cavity; group 3--SGI in a previously acid washed cavity, protected with varnish; and group 4--zinc-free amalgam. A paper cone for dye adsorption analysis was placed in contact with retrofill and the main canal was obturated with thermoplasticized gutta-percha. All teeth were coated, immersed in methylene blue dye, and evacuated to assure complete penetration of the dye in any possible void. Later the teeth were cleared and evaluated under stereomicroscope. Statistical analysis showed that group 1 had the least microleakage of all. In addition, the biocompatibility of the SGI and varnish was compared with that of amalgam using the 51Cr release evaluation method. The results showed that SGI and varnish were less cytotoxic than amalgam. It was concluded that SGI cement can be considered an alternative retrograde filling material.

Cermet Cements↗

Utilization of gutta-percha for retrograde root fillings.

Just as gutta-percha used with a root canal sealer is a recommended material for orthograde root fillings, it could similarly be the material of choice for retrograde fillings. Unfortunately, clinical accessibility and visibility do not always facilitate such a technique. The aim of this article is to present a new technique which enables retrograde fillings to be achieved with gutta-percha and a sealer. After the apex had been resected, a hole was drilled perpendicular to the plane of section of the apex about 1 mm coronally. The bucco-lingual depth required to reach the main canal was calculated. The cavity was then dried, coated with the sealer, and obturated with gutta-percha in accordance with thermo-mechanical compaction techniques. After excess filling material had been removed, the gutta-percha was cold burnished and the angles of the root were smoothed. Clinical cases illustrating healing of the periapical tissues are shown.

Apicoectomy↗

Ultrasonic preparation and obturation of root-end cavities.

This study evaluated the preparation of root-end cavities using an ultrasonically activated file, and the obturation of such cavities. In the first part, the root canals of 40 extracted teeth were prepared to size 40 and irrigated with NaOCl and EDTA. The root ends were resected and the teeth inoculated with Enterococcus faecalis, incubated for 10 days and divided into four groups: control; saline; irrigation; hand instrumentation performed via a retrograde approach up to size 50 using saline irrigant; ultrasonic instrumentation with prebent size 40 K-flex file inserted into a Piezon Master using saline irrigant. The teeth were fixed, sectioned longitudinally and viewed under scanning electron microscopy. Bacterial and smear layer scores were obtained at 1, 3, and 5 mm from the resected end. The bacterial scores for control and saline groups were similar; the scores for each instrumentation group were significantly lower than the control group (P<0.001). In addition, there were significantly fewer bacteria in the ultrasonic group compared with the hand instrument group (P<0.001). The smear layer scores for control and saline groups were similar, and significantly lower than in either instrumentation group (P<0.001). In the second part, root-end cavities were ultrasonically prepared in 20 extracted teeth. Ten cavities were filled with amalgam, and 10 with thermoplasticized gutta-percha and Grossman's sealer. After 24-h storage, the root ends were immersed in dye for 48 h. Cross-sectional slices of the obturated part of the root were evaluated using both light and confocal microscopy for dye leakage along the interface of filling material and dentine. There were no statistical differences between the leakage of amalgam and gutta-percha root-end fillings, nor between the two methods of microscopy.

Dental Alloys↗

Incidence of root face alteration after ultrasonic retrograde cavity preparation.

PROBLEM: Ultrasonic root end preparation is now a recognized clinical procedure. Advantages claimed include improved access to the surgical site (because of reduced root end bevel), and faster more conservative preparation of the root end cavity. However, cracking of the root face has been reported after preparation. OBJECTIVES: The aim of this study was to determine the incidence of root end cracking at varying ultrasonic power levels with a replica technique and scanning electron microscopy. STUDY DESIGN: The root canals of 55 single-rooted teeth were prepared to size 40 apically and obturated with laterally condensed gutta perch and sealer. Root ends were resected at 90 degrees 3 mm from the apex. Class 1 cavities (n = 5) were prepared with retro tips in a Neosonic handpiece with different power settings. Time of preparation and load applied were constant. Another experimental group (n = 5) was prepared with a no. 1 rotary bur. A replica technique with addition-cured silicone impression material and epoxy resin was used to prevent drying artefacts. Specimens were viewed under scanning electron microscope for alterations of the root face. RESULTS: Results showed no root face cracking across the full range of instrument power settings, although chipping of the retrograde cavity margins was observed. No cracking was noted in bur-prepared teeth.

Analysis of Variance↗

Orthograde retreatment and apexification after unsuccessful endodontic treatment, retreatment and apicectomy.

AIM: To describe a case where a second orthograde retreatment was successful in the management of an infected mandibular right first molar that previously had received both orthograde and retrograde treatments. SUMMARY: Periapical surgery is unlikely to be successful unless the root canal system has been adequately debrided and sealed. A case is described where orthograde endodontic treatment, retreatment and apicectomy were unsuccessful in the management of and infected mandibular right first molar. The periapical radiolucency eventually disappeared following a second orthograde retreatment. Teh second retreatment included 12 months of intracanal calcium hydroxide placement to promote apexification, thus allowing subsequent controlled obturation with gutta percha and AH26. At a 5-year review following completion of treatment, the tooth remained asymptomatic and was in normal function. KEY LEARNING POINTS: Orthograde retreatment is a treatment option to manage refractory lesions in teeth that have previously received endodontic treatment, retreatment and apicectomy. Orthograde retreatment using long-term intracanal calcium hydroxide can help promote root-end closure of a resected apex.

Apicoectomy↗

Evaluation of three silicone-based materials as potential retrograde fillings in surgical endodontics.

Endodontic therapy has played an important role in maintaining the integrity of the natural dentition as a fully functional and esthetic masticatory apparatus. Although the sealing of the root canal system is usually accomplished by the conservative endodontic approach, cases which have failed or which involve perforations, broken instruments, or post-crown restorations are almost always treated surgically by using zinc-free amalgam as a retrograde filling material. However, the literature is controversial concerning the health risks and benefits of this material. For this reason, the study presented here was initiated to evaluate the potential of (a) a medical grade silicone-titanium mesh compound; (b) Endo-Fill (Lee Pharmaceuticals, El Monte, CA); and (c) an experimental expanding Endo-Fill (Lee Pharmaceuticals) as alternatives to amalgam. The three silicone-based materials and amalgam were compared for linear apical dye leakage. The leakage study involved 80 teeth which were instrumented, obturated, and prepared surgically for one of the four test materials. Either the teeth were placed immediately into 1% methylene blue dye or the material was allowed to set for 24 h before placement into the dye. Endo-Fill showed significantly less leakage than did the other materials in both the immediately placed and the 24-h set groups. On the other extreme, the experimental expanding Endo-Fill allowed significantly more dye penetration than did amalgam and the other silicone variations.

Bicuspid↗

Managing the difficult airway: a survey of residency directors and a call for change.

This study examines airway management issues in Emergency Medicine residency programs (EMRP) including; airway adjunct availability and frequency of use, number of pediatric intubations, approach to trauma airways, and teaching methods. Surveys were distributed to all accredited EM program directors, who were asked about these issues. Availability of airway adjuncts among respondents included: cricothyrotomy kits (94.9%), fiberoptic scopes (76.3%), Bougies (69.5%), LMAs (66.1%), intubating LMAs (61.0%), lighted stylets (54.2%), retrograde intubation kits (49.2%), Combitube (45.8%), and esophageal obturator airways (15.3%). Responses indicated that 93.6% of airways were orotracheal intubations. A small percentage of intubations used airway adjuncts. Programs use didactics, mannequins, cadavers, direct care and operating rooms for airway training. Emergency Physicians (EPs) are responsible for trauma airways in 89.9% of programs. Most programs have multiple airway adjuncts available, but they are rarely utilized. EPs must become proficient with airway adjuncts. EMRPs must increase resident exposure by using airway adjuncts during routine intubations.

Child↗

[Technique, difficulties and results of endoscopic retrograde cholangio-pancreatography (ERCP)].

Endoscopic retrograde cholangio-pancreatography belongs to the diagnostical equipment of gallduct obstruction and obturation. ERCP is indicated if any doubts arise with the usual clinical diagnostic methods, laboratory, or x-ray studies. This paper presents the technique of ERCP and the several steps in its operation: pylorus passage, description and evaluation of the papilla of Vater and insertion of the papilla. Daily practice and patience produce successful work without complications. Rate of complication in 604 ERCP procedures = 2%. No lethal outcome was observed.

Cholangiography↗