Richard M. Zillich

Root canal morphology of mandibular first and second premolars

Abstract A total of 1,393 first and 938 second mandibular premolars were radiographically examined and mechanically probed to determine the percentage of these teeth which had more than one root canal. A second or third canal existed in at least 23.1 per cent of the first mandibular premolars and in at least 12.1 per cent of the second mandibular premolars.

The influence of the major and minor foramen diameters on apical electronic probe measurements

There have been conflicting reports on the accuracy of electronic devices used for determining working length. The influence of the major and minor diameters on electronic probe measurements were evaluated to ascertain whether anatomical features of the apical portion of the canal might be responsible for these discrepancies. Forty-seven nonrestorable teeth selected from 22 patients were studied. Conventional access was made. A Kerr file was placed to a position 0.5 mm from the major foramen as registered by the Neosono-D apex locator. The electronic probe length was then measured. After the tooth was extracted, the file was fixed with autopolymerizing composite in the canal. A Buehler Isomet lapadary saw was used to prepare specimens to a thickness of 500 microns. A Bioquant II Image Analysis System was used to measure and record distances. It was found that as the width of the major foramen increased, the discrepancy between the electronic probe tip length induction and the actual position of the major foramen increased.

Average maximum post lengths in endodontically treated teeth

T here is a controversy in regard to recommended post lengths for endodontically treated teeth. Varying lengths have been advocated without comparing them with limits set by root canal therapy or anatomic lengths. A comparison of advocated post length with tooth length and the obturated root canal allows the establishment of broad clinical guidelines for the dentist. Paladino’ suggests that a post longer than 5 mm may be adequate to reduce dentinal stresses. Other authors suggest post lengths that are (1) equal to or greater than the length of the clinical crown,2-4 (2) equal to the length of the anatomic crown,’ (3) half to two thirds of

Silver point retreatment: Review and case report

Silver point removal techniques are reviewed. A case report using an ultrasonic scaler as an aid in silver point retreatment is presented. The limitations and uses of this technique are discussed.

Evaluation of internal sealing ability of three materials

Thirty-six maxillary central incisors were prepared in a manner similar to nonvital bleaching procedures. They were examined with respect to the degree of procion green dye penetration of dentin with and without heating. Cavit, IRM, and zinc phosphate cement were used to evaluate their sealing ability. Cavit and IRM provided better internal sealing of the dentin than did zinc phosphate cement.

Maxillary lateral incisor with two roots and dens formation: a case report.

Summary A case report is given to increase the practitioners awareness of aberrations in tooth morphology of maxillary lateral incisors.

Apical sealing ability of thermafil following immediate and delayed post space preparations

Sixty extracted human teeth were prepared in a step-back flare method. Forty-five were obturated with plastic Thermafil and 15 were filled with lateral condensation. The Thermafil filled teeth were divided into three groups consisting of no post preparation, immediate post preparation, or delayed post preparation. Post preparations were not performed (controls) on the laterally condensed specimens. After 10 days of exposure to methylene blue dye, the specimens were decalcified in nitric acid for 72 h. A volumetric analysis measuring absorbance was then performed on each specimen. Within the testing parameters, no significant differences in leakage were observed among the tested groups.

Endodontic access to maxillary lateral incisors

One hundred thirty-one maxillary lateral incisors were radiographed from a mesiodistal vantage point. Projections of the buccal and lingual walls onto the incisal showed that 16 percent opened to the buccal of the incisal edge; 32.9 percent were buccal and inclusive of the incisal edge, 43.5 percent were buccal and lingual to the incisal edge, 6.9 percent were inclusive of the lingual to the incisal edge, and 0.8 percent were entirely to the lingual of the incisal edge. Theoretically, the highest success rate that could be achieved for that portion of endodontic therapy that depends upon canal débridement would be gained by having the occlusal access opening in the most direct path to the long axis of the root canal. In this study it has been shown that, for maxillary lateral incisors, that path would necessitate that out occlusal opening be made inclusive of and slightly buccal to the incisal edge.

A model system for the evaluation of techniques for destaining teeth containing tetracyclines

A model system was developed and tested to simulate tetracycline-stained teeth. There is now a valid model system available on which objective results can be obtained for improvements in clinical treatment of patients.

Ceramic implants--a clinical caution.

A case is presented which emphasizes that clinical as well as roentgenographic criteria must be considered when evaluating the success of the hydroxylapatite materials.