David L. Pitts

Diagnosis and treatment of vertical root fractures

The characteristics of vertical root fractures are discussed along with various factors useful in detection and determination of their extent. Treatment alternatives which depend upon the location and extent of the fractures are presented.

Further investigation of spreader loads required to cause vertical root fracture during lateral condensation

The roots of 54 extracted human mandibular incisorswere instrumented, measured, and then filled with gutta-percha by lateral condensation on an Instron testing machine until vertical root fracture occurred. A spreader load as small as 1.5 kg (3.3 lb) produced a fracture, and 13% of the sample fractured at a load of 3.5 kg (7.7 lb) or less. Computer bivariate correlation analysis revealed significant positive linear correlations (p

An in vitro study of spreader loads required tocause vertical root fracture during lateral condensation

Forty-four extracted human maxillary central incisors, maxillary canines, and mandibular canines were filled with gutta-percha by lateral condensation on an instron testing machine until vertical root fracture occurred. A spreader load as small as 7.2 kg produced a fracture in a maxillary central incisor. Sixteen percent of the sample fractured at a load of less than 10 kg. No statistically significant correlation was found between fracture load and root dimensions. However, a statistically significant linear correlation did exist between the fracture load and the load rate at fracture (p

Investigation of the role of endotoxin in periapical inflammation

Abstract Dental pulps in two dogs were removed and the canals shaped in six matched pairs of roots. Canals on the experimental side were injected with Salmonella minnesota R-595 endotoxin and canals on the contralateral control side were injected with saline solution at weekly intervals. Radiographic examinations were performed weekly, and histologic evaluations were made at four to five weeks. Periapical radiographic changes occurred sooner and to a more severe degree with the roots containing endotoxin than with the roots containing saline solution. Histologic evaluation showed greater periapical bone destruction and a more marked inflammatory response. Polymorphonuclear leukocytes were the predominating cells. The results of this study indicate that endotoxins may have a role in periapical inflammation and bone destruction.

A histological comparison of calcium hydroxide plugs and dentin plugs used for the control of gutta-percha root canal filling material**

Apical foramina of 36 vital maxillary and mandibular canines in nine mature cats were enlarged with a size 50 K file worked 1 to 11/2 mm beyond the radiographic apex. One side was randomly selected to receive a calcium hydroxide powder plug packed into the apical canal and the contralateral side received a dentin filing plug. The canals were then filled with gutta-percha and sealer using a formed cone with lateral condensation technique. At 1, 3, and 9 months, three animals were sacrificed and histological evaluation of the teeth and periapical tissues performed. Calcium hydroxide and dentin plugs worked equally well to control the filling material. However, the calcium hydroxide plugs tended to wash out of the canals quickly, whereas the dentin plugs were intact at 9 months. Both plugs resulted in significant calcification at the foramen, but the onset, pattern, and extent differed. The calcifications associated with the dentin plugs were more complete than those observed with calcium hydroxide plugs. The appearance of the calcifications was consistent with that of cellular cementum. No significant difference in periapical inflammation was noted after 1 month and no significant difference in periapical healing was observed. By 1 month, no inflammation was associated with calcium hydroxide particles or dentin filings present in the periapical tissues.

A radiographic comparison of two root canal instrumentation techniques

The ability of two instrumentation techniques to negotiate and enlarge small curved canals was com-compared radiographically. Fifty canals in extracted human molar teeth were instrumented by the progressive enlargement (PE) technique, a form of step-back preparation using standard K files, or by the balanced force (BF) technique using K files whose tips had been specially modified. By using drawings and projected radiographic images of the files, the position of the largest file used in the apical preparation, #30 or #35 for the PE technique and #45 for the BF technique, was compared with the position of a small file placed in the canal before instrumentation. The PE and BF techniques were equally capable of instrumenting small curved canals to their respective largest apical preparation sizes. However, at sizes equivalent to the largest apical preparation sizes used in the PE technique, the BF technique produced significantly less deviation from the center of the original canal.

Evaluation of the apical seal produced by the McSpadden Compactor and by lateral condensation with a chloroform-softened primary cone

One hundred seventy single-rooted teeth were tested in vitro to evaluate the apical seal produced by the McSpadden Compactor and lateral condensation with a chloroform-softened primary cone. The obturated teeth were centrifuged in India ink, decalcified, and cleared. The degree of ink penetration into the canal provided a measure of the apical seal. Teeth filled with gutta-percha and Grossmans sealer using the McSpadden Compactor had statistically less apical leakage than teeth filled with a chloroform-softened primary cone and sealer using lateral condensation (p

A case of talon cusp associated with other odontogenic abnormalities

This report presents a case of talon cusp associated with several other odontogenic abnormalities. It also notes several cases which indicate that pulp horns may be absent in talon cusps and that primary teeth may demonstrate talon cusp formation.

Determination of impedance changes at varying frequencies in relation to root canal file position and irrigant.

This study was conducted on 10 anterior and premolar teeth that were scheduled for endodontic treatment. After length of tooth determination, a series of test K-file handles were locked at lengths varying from 3 mm short to 0.5 mm long of the foramen. Samples of impedance were taken at each length with a digital signal processor at six different frequencies and for each of seven different irrigants or canal conditions. A total of five different root canal irrigants were used in each tooth (RC Prep, 70% isopropyl alcohol, 14.45% EDTA sodium solution, normal saline, and 5.25% NaOCl), along with two variations of a dry canal. The greatest impedance changes occurred +/- 0.25 mm from the foramen. No significant difference was noted in prediction error at different frequencies (p > 0.05); however, prediction error was significant with respect to different irrigants (p < 0.02). Conductive irrigants demonstrated less change of electrical characteristics with length than nonconductive irrigants, thus allowing a greater prediction of file position in relation to the foramen using electrically nonconductive irrigants.

An investigation into the feasibility of photobleaching tetracycline-stained teeth

Aqueous solutions of tetracyline hydrochloride (TC) were irradiated with two different sources of high-intensity UV light through quartz and through methacrylate spectrophotometric cuvets to determine the most effective wavelengths for photobleaching discolored TC. Hydrogen peroxide was also added to discolored TC solution. Results were determined spectrophotometrically. Sprague-Dawley rats were given daily intraperitoneal injections of two times the usual human dose of TC. Samples of discolored dentin from the mandibular incisors of these rats were irradiated with the two UV light sources. Results were recorded photographically using stained and nonstained control tooth segments for comparison. The two sources of relatively intense shortwave UV light (200 to 300 nm) successfully photobleached the TC-stained rat dentin within 12 to 24 h. Shortwave UV light appeared to be more efficient for photobleaching of discolored aqueous TC solutions than longer wavelength light. Hydrogen peroxide was seen to bleach discolored aqueous TC solution.