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At least 271 records · Page 15Linked to original sources
PubMed1998

A photoelastimetric analysis of stress induced by root-end resection.

The aim of this study was to place into perspective some factors that played an important role in the healing of periapical lesions after surgical endodontic procedures. Root-ends were sectioned at different angulations on models and analyzed by photoelastimetry. Results showed that a section of the root-end through a plane perpendicular to the long axis of the tooth offers a better distribution of the stresses exerted on the apical region that the use of an inclined plane. The biological implications of these results have led the authors to propose a plan of resection that is perpendicular to the long axis of the tooth instead of the inclined plane commonly used.

Birefringence↗
PubMed1999

In vitro sealing ability of dentin bonding agents and cavity varnish with amalgam as retrofills.

The aim of this study was to test the effect on the seal produced by an amalgam retrofill of two dentin bonding agents (Amalgambond and All-Bond) and a cavity varnish (Copalite). The three materials were tested when placed before the retrofill (group I) and before and after the retrofill (group II). Ninety teeth distributed into three groups were prepared for the retrofilling. Each group was divided into subgroups of I and II. Linear apical leakage was measured by a stereomicroscope after 1 month in dye. All materials permitted dye leakage around the retrofill, regardless of the application type. No statistical difference was found between the Amalgambond subgroups or between the All-Bond subgroups. There was less leakage in varnish group I than group II. Amalgambond group I leaked significantly less than All-Bond group I.

Analysis of Variance↗
PubMed1999

Clinical applications of mineral trioxide aggregate.

An experimental material, mineral trioxide aggregate (MTA), has recently been investigated as a potential alternative restorative material to the presently used materials in endodontics. Several in vitro and in vivo studies have shown that MTA prevents microleakage, is biocompatible, and promotes regeneration of the original tissues when it is placed in contact with the dental pulp or periradicular tissues. This article describes the clinical procedures for application of MTA in capping of pulps with reversible pulpitis, apexification, repair of root perforations nonsurgically and surgically, as well as its use as a root-end filling material.

Aluminum Compounds↗
PubMed1999

Cytotoxic evaluation of root-end filling materials in cultures of human osteoblast-like cells and periodontal ligament cells.

The cytotoxicity of three root-end filling materials (amalgam, IRM, and Super-EBA) was evaluated in cultures of human periodontal ligament cells and human osteoblast-like cells. Ten-millimeter-long plastic test tubes were filled with 3 mm of freshly mixed root-end filling materials at one end (1.5 mm diameter). The opposite end was sealed and attached by heat to a 35-mm cell culture dish. Human periodontal ligament cells and human osteoblast-like cells were seeded in the dishes. The size of cell-free zones around the root-end filling materials and the total cell number per dish were calculated after 3 and 7 days. Empty test tubes used as controls did not influence the growth and distribution of the cultured cells. Cell density increased in all groups in the test period. Amalgam had a larger cell-free zone, compared with IRM and Super-EBA and showed a reduction in total cell number per dish for both tested cell types. IRM and Super-EBA also had a cell-free inhibition zone for both cell types, but no significant reduction in total cell number per dish. This study showed that amalgam had a higher cell toxicity to human periodontal ligament cells and human osteoblast-like cells than IRM and Super-EBA.

Analysis of Variance↗
PubMed1999

Results of endodontic retreatment: a randomized clinical study comparing surgical and nonsurgical procedures.

Information of "success" rates after surgical or nonsurgical endodontic retreatment is abundant but inconclusive. Reported healing frequencies vary between 45% and 90%. The present study was designed to find any systematic difference between the methods. Nonsurgical and surgical retreatment was randomly assigned to 95 endodontically "failed" cases. The outcome of the procedures was clinically and radiographically recorded, and followed for 4 years. At the 12-month recall, a statistically significant (p < 0.05) higher healing rate was observed for cases surgically retreated. At the final 48-month examination, no such difference was found. These findings may be explained by (a) slower healing dynamics in the nonsurgical group and (b) the event of late "failures" in the surgical group. Within the latter category, four cases classified as healed after 1 yr failed at the final follow-up. Conclusively, this study failed to show any systematic difference in the outcome of surgical and nonsurgical endodontic retreatment. Surgical retreatment seems to result in more rapid periapical bone fill, but also may imply a higher risk of "late failures." From a scientific point of view, the length of the follow-up period is very important and may strongly influence the conclusions made.

Adolescent↗
PubMed1999

Root deformation during root-end preparation.

Ultrasonic root-end preparation techniques have recently been introduced and revolutionized the field of endodontic surgery. However, several reports claimed that there was an increasing incidence of crack formation after ultrasonic root-end preparation. As yet, little work has focused on the root deformation during root-end preparation. Thus, the purpose of this investigation was to measure the amount of root deformation during root-end preparation with the use of microhandpiece and ultrasonic systems by using strain gauge methods, and simultaneously to detect any cracks with the aid of the stereomicroscope, stain, and an image processing system. The results demonstrated the ultrasonic instrumentation produced significantly greater strain on average than that generated with the microhandpiece system. From the viewpoint of fracture, any technique that could diminish the strain on the root would decrease the likelihood of fracture; however, no crack was observed on any resected surface of roots in this study.

Dental Instruments↗
PubMed1999

Evaluation of diamond-coated ultrasonic instruments for root-end preparation.

Ultrasonic instrumentation has been associated with cracking of the dentin in the area of the root-end preparation. The purpose of this study was to evaluate root-end preparations for cracking and to describe cavosurface morphology after the use of diamond-coated instruments. Forty teeth were inspected for intradentin cracks, incomplete canal cracks, and complete canal cracks before and after preparation with a stainless steel CT-5 ultrasonic instrument and again after root-end preparation with an S12D/90 degrees diamond-coated instrument. Six teeth had polyvinylsiloxane impressions taken of the root ends after preparation with the CT-5 and again after preparation with the diamond-coated instrument. Replicas were made, split, sputter-coated, and inspected using the scanning electron microscope. This study indicates that use of the diamond-coated instrument for root-end preparation does not result in significant root-end cracking and that it can remove cracks created by a prior instrument's use. The use of the diamond-coated instrument resulted in a heavily abraded, debris-covered cavosurface that may affect the apical seal.

Analysis of Variance↗
PubMed1999

Longitudinal microleakage evaluation of Super-EBA as a root-end sealing material.

This study evaluated the sealing ability of fast and regular set Super-EBA with different powder-to-liquid ratios as a root-end filling material. Fifty extracted maxillary central incisors were uniformly cleaned and shaped using a crown-down technique with Gates-Glidden drills and Profile series 29.04 taper rotary instruments. After root-end resection and ultrasonic preparation, 48 root sections were randomly assigned to 4 groups of 12 teeth each and filled with a thick or thin mix of fast or regular set Super-EBA. Fast and regular set Super-EBA were mixed to a thick (1 scoop powder:1 drop liquid) or a thin (1 scoop powder:2 drops liquid) consistency. Positive and negative controls were used. Microleakage was assessed at 24 h, 72 h, 1 wk, 2 wk, 4 wk, 6 wk, and 8 wk using a fluid filtration system. There were no significant differences in the microleakage measured for any group at any of the time points evaluated. These results suggest that either fast or regular set Super-EBA mixed to various consistencies may be acceptable for root-end filling.

Analysis of Variance↗
PubMed1999

A scanning electron microscopic study of in vivo ultrasonic root-end preparations.

The purpose of this in vivo study was to evaluate root-ends for cracks after root resection and again after ultrasonic root-end preparation in patients undergoing endodontic surgery. Endodontic surgery was performed on 25 roots from 20 patients. In vivo vinyl polysiloxane impressions were made after root resection and again after ultrasonic root-end preparations. Epoxy resin casts were made from the impressions and scanning electron micrographic examination of the root-end replicas was performed. There was no evidence of cracks after root resection. One incomplete canal crack was evident after ultrasonic root-end preparation.

Apicoectomy↗
PubMed1999

Histological study of periapical tissue healing in the rat molar after retrofilling with various materials.

We histologically examined the effects on the periapical tissue of various dental filling materials applied as retrofillings in rats and compared them with those of amalgam. The 4-META-TBB resin Superbond and the light-cured composite resin produced the least severe inflammatory reaction, with the greatest amount of new bone. In these specimens, regeneration of a part of the periodontal ligament was also observed. These results indicate that these materials might be very biocompatible and thus foster the natural regeneration of the periapical tissue.

Animals↗
PubMed1996

Ultrasonic root-end preparation: clinical and radiographic evaluation of results.

PURPOSE: This study evaluated the results of periradicular surgery performed using ultrasonic root-end preparation. PATIENTS AND METHODS: The course of healing during observation periods ranging from 6 months to 3 years was examined in 157 teeth. RESULTS: One hundred forty-five teeth were successfully treated, for a success rate of 92.4%. CONCLUSION: It was concluded that the ultrasonic root-end preparation technique for periradicular surgery is a simple procedure that provides excellent results.

Adolescent↗
PubMed1999

Root-end cavity preparation after apicoectomy using a new type of sonic and diamond-surfaced retrotip: a 1-year follow-up study.

PURPOSE: This study evaluated the outcome of periradicular surgery using a new set of retrotips for root-end cavity preparation. PATIENTS AND METHODS: Forty-three patients who had 50 consecutively treated teeth with periradicular pathology were enrolled in this prospective study. After apicoectomy, root-end cavity preparation was performed, using diamond-surfaced retrotips driven by a sonic handpiece; EBA-cement was used as the root-end filling material. Healing assessment was based on clinical and radiographic criteria. RESULTS: At the 1-year follow-up, 82% of the reexamined surgical cases presented with successful healing. Fourteen percent of the treated teeth were deemed as improved (partial healing), and 4% were classified as failures. CONCLUSION: The new retrotips were found to be ideal for root-end cavity preparation. They simplify the surgical approach to root ends where the working space is limited by restricted access. Root-ends prepared with this new sonoabrasive technique yielded excellent results at the 1-year follow-up examination.

Adolescent↗
PubMed1987

Observer strategy and the radiographic classification of healing after endodontic surgery.

An observer strategy involving trained and experienced examiners was used in a large series of endodontic surgery cases, evaluated radiographically 1 year after the operation. The cases were grouped in 1 of the following 4 healing groups; complete healing, incomplete healing (scar tissue), uncertain healing and unsatisfactory healing (failures). The radiographs were first examined separately by an oral surgeon and an endodontist. Deviating cases were subjected to joint evaluation. The overall agreement before joint interpretation was satisfactory: 63% when corrected for chance agreement. Agreement after joint evaluation reached 94% of the total material. Disagreement and difficult borderline cases were judged by an oral radiologist. He was more pessimistic than the 2 main examiners. The identification of healed cases with apical bone which had not yet obtained normal radiopacity and structure was difficult. Altogether, the observer consistency was satisfactory; the selection of experts increased the chances of "true" diagnoses; the important screening function of the one-year control was confirmed. The applied strategy and the classification are recommended for follow-up studies.

Classification↗
PubMed1987

Glass-ionomer cement as retrograde filling material. An experimental investigation in monkeys.

The tissue reaction following the use of glass-ionomer and amalgam, as retrograde filling materials was investigated in an experimental study using 8 monkeys. After apicectomy of the upper central incisors, amalgam and glass-ionomer cement was used at random as retrograde filling material. 2 animals at a time were sacrificed after 2 weeks, 1, 3 and 6 months. Irrespective of the length of time, the tissue reactions were similar for the 2 materials. 2 weeks after surgery, a vascular granulation tissue containing lymphocytes, plasma cells and polymorpho-nucleated leukocytes was observed close to the retrograde fillings. 1 month after surgery, good healing was found, the granulation tissue being replaced by new osteoid or bone formation. After 3 and 6 months, there was complete healing with no inflammatory reaction and a mature alveolar bone surrounding the apicectomized roots.

Animals↗