Mahmoud E. ElDeeb

Adhesion of sealer cements to dentin with and without the smear layer

The influence of a smear layer on the adhesion of sealer cements to dentin was assessed in recently extracted human anterior teeth. A total of 120 samples was tested, 40 per sealer; 20 each with and without the smear layer. The teeth were split longitudinally, and the internal surfaces were ground flat. One-half of each tooth was left with the smear layer intact, while the other half had the smear removed by washing for 3 min with 17% EDTA followed by 5.25% NaOCI. Evidence of the ability to remove the smear layer was verified by scanning electron microscopy. Using a specially designed jig, the sealer was placed into a 4-mm wide x 4 mm deep well which was then set onto the tooth.

An evaluation of the use of amalgam, Cavit, and calcium hydroxide in the repair of furcation perforations.

The purpose of this study was to compare the clinical, radiographic, and histo[ogic changes that occur in response to three of the most commonly used materials to repair furcation perforations. The results of the experiment showed that amalgam was superior to Cavit and calcium hydroxide as a sealing material of furcation perforations. The most severe reactions occurred in the control group where the perforations were not filled.

The sealing ability of the Thermafil obturation technique.

Forty straight canals of maxillary canines and 40 curved canals in 20 mesial roots of mandibular molars were instrumented and randomly assigned to two groups of 40 canals each. For the experimental group, the canals were obturated using the Thermafil obturation technique. Lateral condensation was used for the obturation of the control group. Kerr pulp canal sealer was used in both group. The specimens were stored in 100% humidity for 1 wk. All teeth were suspended in black India ink for 14 days and decalcified in 5% nitric acid over a 2-day period. The teeth were then dehydrated in a graded series of alcohol to 100%. Methyl salycilate was used to clear and store the teeth for 48 h. Linear dye leakage measurements showed that canines obturated with the lateral condensation technique leaked significantly less than those obturated using the Thermafil technique (p = 0.02). The difference was not statistically significant in the molar roots.

The use of a dentinal bonding agent as a root canal sealer

The quality of the apical seal obtained with laterally condensed gutta-percha and an experimental sealer (Scotchbond) as compared with a commonly used sealer (Tubliseal) was assessed in 40 recently extracted maxillary canines. By using 2% methylene blue dye as a tracer, the quality of the apical seals was assessed by measuring the linear dye penetration. Canals obturated with gutta-percha and Scotchbond leaked significantly less than when gutta-percha and Tubliseal were used.

An in vitro assessment of the quality of apical seal of thermomechanically obturated canals with and without sealer

The quality of the apical seal obtained with laterally condensed gutta-percha with sealer, and thermomechanically condensed gutta-percha with and without sealer was assessed in 60 recently extracted maxillary central incisors and canines. Using 2% methylene blue dye as a tracer, the quality of the apical seals was assessed by measuring dye leakage linearly and quantitatively via a spectrophotometric method. No statistically significant difference in leakage was observed between the lateral condensation and thermomechanical condensation groups providing sealer was used. When sealer was not used in association with thermomechanical condensation of gutta-percha, leakage increased 5- to 20-fold.

Removal of canal obstructions with the endo extractor

This report describes a series of clinical cases demonstrating the use of the Endo Extractor to remove canal obstructions. Each of the obstructions was removed with the new technique after conventional methods had failed. Preoperative, working, and postoperative radiographs are shown.

Hand versus ultrasonic instrumentation: Its effect on canal shape and instrumentation time

The resulting root canal shape after using ultrasonic and hand instrumentation techniques as well as the instrumentation time was studied in 63 extracted human mandibular first and second molars. The mesial canals were instrumented alternating the techniques between the buccal and lingual canals. After instrumentation, the roots were sectioned horizontally, in the, apical, middle, and coronal thirds and evaluated for shape and location. The mean hand instrumentation time, 8 min, was significantly less than the mean ultrasonic instrumentation time, 11 min (p

Apical sealing ability of metal versus plastic carrier thermafil obturators

Sixty straight maxillary canines, 40 straight mandibular incisors, and 40 curved mesial canals of 27 mandibular molars were instrumented and randomly assigned to one of seven groups of 20 canals. Experimental groups were obturated with metal or plastic carrier Thermafil obturators. Control groups were obturated using the lateral condensation technique. An additional group of 20 unobturated curved molar canals served as positive controls. Kerr Pulp Canal Sealer was used in all obturation groups. The presence or absence of apical extrusion of gutta-percha was recorded. Teeth were suspended in black India ink for 2 wk, cleared, and then examined under a dissecting microscope at x20 magnification. No leakage was found in any of the obturated canals, whereas unobturated controls showed total dye penetration. Plastic carrier Thermafil and metal carrier Thermafil groups produced a significantly greater incidence of apical extrusion of gutta-percha compared with lateral condensation groups (p < 0.001). Extrusion for Thermafil groups occurred significantly more frequently in straight compared with curved canals (p = 0.002). The Thermafil groups showed a higher frequency of filled lateral and accessory canals than in the lateral condensation group; however, this was statistically insignificant (p = 0.48).

Removal of hard paste fillings from the root canal by ultrasonic instrumentation

A technique for removing hard pastes from the root canal is presented and supported by two cases. This technique was found to be safe and effective. It allowed the retreatment of the involved teeth without the need for surgical intervention and may be considered by other clinicians.

Evaluation of the repair of mechanical furcation perforations using amalgam, gutta-percha, or indium foil

The response of supporting tissues to the repair of furcation perforations using amalgam, gutta-percha, or indium foil was investigated. Forty-eight maxillary posterior teeth in eight adult mongrel dogs were treated endodontically. Immediately thereafter, mechanical perforations were created in the furcations and promptly filled with the three test materials. The coronal openings were all filled with amalgam. The animals were divided into a 2-month group and a 6-month group. Based on clinical, radiographic, and histological findings, amalgam and gutta-percha showed significantly better results than indium foil. No significant differences existed between amalgam and gutta-percha.