Occurrence of torus palatinus and mandibularis among women of different ethnic groups.

PURPOSE: To detect the presence of tori in women of different ethnic groups residing in the metropolitan area of Washington, D.C., USA. MATERIALS AND METHODS: 448 females between the ages of 18-88 years participated in the study. There were 302 African Americans, 62 Caucasians, 43 Hispanics, 36 Asians, and 5 Native Americans. RESULTS: Tori were detected in 107 African Americans (35.4%), 20 Caucasians (32.3%), 13 Hispanics (30.2%), 14 Asians (38.9%), and 1 of the 5 Native American (20%), (P = 0.328). Torus palatinus were found in 69.7% of women from all ethnic groups (P = 0.107). Slightly higher percentage was seen in the Hispanics, then the African Americans, with the least in the Caucasians. Torus mandibularis were found only in 38.7% of all subjects (P< 0.05), were more common among Caucasians, and were usually bilateral. The presence of both tori was only detected in 8.4% of the participants. There was no relationship between age and the presence of torus mandibularis (r = 0.074) or palatinus (r = 0.008).

Microleakage evaluation of two newly introduced hybrid glass ionomer cements.

This study evaluated the microleakage of Photac-Fil Aplicap (ESPE) and Fuji II LC (GC) glass ionomer cements. Polished Class V restorations were compared with non-polished restorations. No measurable microleakage was detected after thermocycling and staining in India ink dye. Polishing the restorations had no effect on the degree of microleakage.

Comparison of thermoplasticized gutta-percha root canal obturation technique to the lateral condensation.

This in vitro study compared the quality of filling the root canal by the conventional lateral condensation technique to the fill by the commercially available thermoplasticized gutta-percha method. Subjective radiographic evaluation of density, presence of voids, and extent of fill were made for each of the 20 freshly extracted maxillary central incisors used for this study. Voids were noted in 10% of the laterally condensed canals, versus 40% of those obturated with the thermoplasticized gutta-percha. The mean time (in seconds) to obturate the canals with lateral condensation was 387 (s = 112); of the experimental was 145 (s = 23). We conclude that thermoplastisizing and injecting the gutta-percha into the root canal was a fast and a relatively easy technique, but the resultant filling was no more dense, and was shorter apically than the laterally condensed gutta-percha.

Evaluation of the apical condensation of gutta-percha by a tapered/calibrated spreader/plugger.

This study compared a tapered, calibrated spreader/plugger instrument (M-series) to noncalibrated spreaders and pluggers in achieving apical condensation of gutta-percha in 20 single-rooted human teeth. The distances between the tip of the instruments and the tip of the master gutta-percha were measured. Results showed no significant difference in apical penetration between the D-11 spreader and finger plugger, also no difference between the M-spreader and M-plugger. The mean distance was significantly larger for the D-11 spreader than that for the M-spreader or M-plugger at 99% confidence level. The mean distance of the finger pluggers was significantly higher than that for the M-spreader at the 95% confidence level. Microleakage evaluation of the obturated teeth did not show a statistically significant difference between all four instruments used in this in vitro study.

Microleakage comparison of apical seal of plastic versus metal Thermafil root canal obturators.

This study compared the apical seal of plastic versus metal Thermafil obturators in extracted human teeth. The obturated teeth were evaluated radiographically for the extent and adaptation of the filling obturator. No difference was seen between plastic and metal for over- or underfilling. Voids were seen more often in smaller sizes of both plastic and metal obturators. Obturated teeth were stained in India ink, decalcified, and cleared. Microleakage evaluation of the transparent teeth showed no statistical difference between metal and plastic obturators.

Microleakage comparison of dentin bonding systems with glass ionomer.

Glass-ionomer cements have been suggested as substitutes for dentin-bonded composites. This investigation was designed to compare microleakage of glass-ionomer restorations with that of dentin-bonded composite restorations. Eighty extracted human molars were used in this study. Class V cavities were prepared on the mesial and distal surfaces of each tooth. The distal cavities were restored with Ketac-Fil Glass Ionomer (ESPE). The mesial cavities were divided into four groups and treated with four different dentin bonding systems: Gluma (Columbus Dental), Tenure (two-part powder system; second version, Den-Mat), Scotchbond 2 (3M), and an experimental ferric oxalate system. The commercial materials were placed according to the manufacturers' instructions. The teeth were then thermocycled 3800 cycles between 5 degrees C and 55 degrees C, subjected to silver nitrate staining, and sectioned for microleakage evaluation by three evaluators on a scale of 0 to 4. The ferric oxalate system exhibited significantly less microleakage (median score = 1; Wilcoxon paired testing, p = 0.01) than the glass ionomer (median score = 3). The other dentin bonding systems were similar in microleakage to the glass ionomer (median score = 3).

Comparison of conventional root canal obturation techniques with Thermafil obturators.

This study compared microleakage of Thermafil Obturators to the single cone technique in Lexan blocks simulating root canals (n = 20) stained with Prussian blue dye. The microleakage of Thermafil and laterally condensed extracted human teeth was also investigated after the teeth were stained with India ink or Prussian blue dye over 1- or 2-wk dye immersion periods. In Lexan blocks there was no statistical difference in mean leakage between the single cone technique and Thermafil. Teeth with Thermafil Obturators exhibited greater leakage than those with the lateral condensation. Greater leakage was also seen where India ink was used. Dye immersion time did not have a significant influence on leakage scores. The combination of India ink with Thermafil demonstrated the greatest average leakage. This study demonstrated that Lexan canal simulating blocks do not mimic extracted human teeth for evaluating microleakage.

Pulpal response to tricalcium phosphate as a capping agent.

The purpose of this study was to evaluate tricalcium phosphate (TCP) as a pulp-capping agent. Two adult male beagle dogs were used for this investigation. Class I cavities were prepared in the posterior teeth and Class V cavities in the anterior teeth. With the use of a rubber dam and high speed with water coolant, minimal pulp exposures were created in both the experimental and control teeth, by means of a 1/2 round bur. Zinc oxide-eugenol was the temporary filling material used to restore all cavities. In each dog, five teeth served as control and were capped with the use of calcium hydroxide. In one dog, 10 teeth from two quadrants were capped with the tested material (TCP). In the other dog, 11 teeth were capped with TCP. Four teeth from the fourth quadrant in each dog were capped with a mixture of calcium hydroxide and TCP in a ratio of 1:1 by weight (50/50 group.) The two dogs were killed after 70 days. The histologic evaluation of the response to the capping agents and at the exposure site was recorded. A total of 39 teeth were evaluated in this study. It was found that TCP as a capping agent precipitated the highest mean inflammatory response and also demonstrated the highest percentage of reparative dentin formation.

Comparison of microleakage of experimental and selected commercially available bonding system.

The microleakages of composite restorations bonded with two commercial and two experimental systems were observed. A high-viscosity condensable composite and a low-viscosity composite were used as the restorative materials. The bonding systems used were two widely accepted commercial brands and two experimental systems, one containing ferric oxalate and the other aluminum oxalate. Restorations were placed in cavities prepared in extracted human teeth and treated with the various bonding systems. These restorations were stored in 37 degrees C water for 24 hours and then polished. The restored teeth were subjected to seven days of thermocycling (5 degrees C-55 degrees C for 540 cycles per day). Microleakage was detected and scored from 0-4 according to the degree of stain penetration. The experimental systems had lower scores than the commercial systems. The high-viscosity composite restorations had microleakage scores higher than those of the lower-viscosity composite restorations.

Bonding to tooth structure: clinical and biological considerations.

Marginal leakage of tooth restorations is a problem well known to dental practitioners and researchers. The development of agents that provide strong and stable adhesive bonds to both dentine and enamel in the oral environment is a challenge to scientists. The critical area in resin restorations is at the gingival margin where the resin is in apposition to dentine and/or cementum. Therefore, investigations into dentine bonding have been undertaken over the past 20 years. The evaluation of bonding agents includes studies in vitro to investigate their ability to aid the control of microleakage. The biological safety of bonding agents is also very important. Pulpal response to these agents is useful in biological evaluation. Animal studies on the pulpal response of available bonding agents have been reported recently. Precise evaluation criteria have been employed on a limited basis. Long-term clinical studies are now necessary to evaluate the stability of the commercially available bonding agents that have been histologically and biologically evaluated.

Dilaceration of permanent upper lateral incisors: frequency, direction, and endodontic treatment implications.

A sample of 480 extracted permanent upper lateral incisors was visually examined and the direction of dilaceration was recorded. It was found that 52.1 percent of the roots of these teeth were distolabially dilacerated. Analysis of radiographs of another sample of 442 endodontically treated teeth revealed that distolabial dilaceration occurred in 52 percent of the cases. It is proposed that oversight of the distolabial direction of root dilaceration of upper lateral incisors can be a contributing factor in the failure of endodontic treatment of these teeth.

Effective surface sterilization of gutta-percha points.

A bacteriologic investigation was conducted to determine the sterilizing effectiveness of various germicidal endodontic irrigants on gutta-percha points. It was found that most effective in surface sterilization was a 5-minute treatment using sodium hypochlorite, Zephiran, and hydrogen peroxide in concentrations of 4.50 percent, 0.53 percent, and 3.00 percent, respectively. These agents were potent against gram-positive and gram-negative bacteria as well as endospore-forming microorganisms. Fungal spores were killed only by the first two but not by the latter germicidal agents. On the other hand, ethanol, chloroform, eugenol, betadine, and Gram's iodine solution were found not to be effective for surface sterilization.