Quantitative assessment of dentin bridge formation following pulp-capping in miniature swine.

A quantitative assessment of dentin bridges was conducted on sections prepared from teeth capped with four pulp-capping agents (Bioglass, Life, Demineralized Dentin Matrix, and Teflon) in a micro-swine model. The degree of mineralization of the dentin bridges relative to the adjacent primary dentin was measured using a computer-based image analysis of microradiographs prepared from the sections. The rate of formation of the dentin bridge was measured from fluorescent bands formed in the same sections by a Demeclocycline dentin marker. There were no statistically significant differences in the relative mineral densities of the dentin bridges and the rate of dentin bridge formation under the four pulp-capping agents. These findings support the suggestion that components of the extracellular matrix rather than pulp-capping agents may be important in the formation and mineralization of dentin bridges in repairing dental pulps.

Effect of rotational speed on nickel-titanium file distortion.

Separation of instruments while performing root canals is something that has plagued all practitioners. The purpose of this study was to evaluate the effect of rotational speed on nickel-titanium file distortion and separation. Forty extracted human molars were instrumented with Profile (Dentsply Tulsa Dental Products, Tulsa, OK) ISO .04 rotary nickel-titanium instruments at 166.67 or 333.33 rpm. The instruments were evaluated after instrumentation for separation and/or distortion. The results of this study were statistically significant and indicate that file distortion and/or separation is four times as likely to occur at 333.33 rpm vs. 166.67 rpm.

Comparison of diagnostic accuracy of digital imaging by using CCD and CMOS-APS sensors with E-speed film in the detection of periapical bony lesions.

OBJECTIVE: The purpose of this study was to compare E-speed Plus film and digital imaging with a charge-coupled device (CCD) sensor and a complementary metal-oxide semiconductor active pixel sensor (CMOS-APS) in the detection of periapical bone lesions. STUDY DESIGN: Periapical lesions were created in the cortical and trabecular bone of 10 dried human mandibles. Seventy radio-graphic images and 140 digital images were evaluated by 6 endodontists and 2 radiologists. Receiver operating characteristics curves and analysis of variance were used for statistical analysis.Results. No statistically significant differences were found between film, CCD, and CMOS-APS systems. Lesion detection occurred with significantly greater accuracy in cortical bone than in trabecular bone, as well as when the cortical plate was involved. CONCLUSIONS: That no differences were found between the two sensors lends support for the use of CMOS-APS sensors, which require less system power and may have longer life spans than CCD sensors. Digital imaging required 50% less radiation than film to obtain the same diagnostic information.

Perceived trends in operative dentistry skills: a 10-year comparison.

In this study a random sample of 357 members of dental examiner boards in the United States was surveyed to determine the perceptions of candidate ability on examinations for dental licensure. A response rate of 82% was achieved. Data from this survey were compared to a similar survey conducted 10 years ago. Analysis and comparison of these two surveys indicate that candidate ability in operative dentistry has continued to decline as perceived by dental examiners in the United States over the past decade.

The effect of a training program on the reliability of examiners evaluating amalgam restorations.

There have been long-term problems in establishing agreement among clinical and preclinical examiners in dentistry. The purpose of this study was to develop a training program and study its effect on examiner agreement when judging the clinical service ability of amalgam restorations. Ten examiners with varying backgrounds, levels of experience, and no previous training with methods to standardize clinical evaluation evaluated 44 amalgam restorations in 17 patients before and after a brief training session. The restorations were judged as either acceptable (leave alone), or unacceptable (replacement or alteration required). The training program was brief and consisted of the introduction of a rating scale with descriptive criteria, followed by a clinical session where the examiners practiced using the rating scale and criteria to arrive at operational decisions. Intraexaminer and intraexaminer agreement were calculated for both evaluation sessions. The training program improved the reliability of the examiners evaluating the clinical service ability of the amalgam restorations. Although the gain was not to the level commonly accepted in the literature, it clearly demonstrates a step in the right direction.

Decisions of practitioners regarding placement of amalgam and composite restorations in general practice settings.

This study was undertaken to analyze the current reasons practitioners in general practice settings choose to place amalgam and composite restorations. Data were gathered on individual restorations in the clinical setting to provide information on reasons practitioners state that restorations are placed, the type of material most often placed in different restoration classifications, and the age of restorations at the time of replacement. The results of this study indicate that approximately one-half of all restorations, both amalgam and composite, were placed to treat primary caries. One-half of the remaining restorations placed, i.e., not including those with primary caries, were placed to treat recurrent caries. With respect to restorative materials, amalgam was most often placed in class 1 and class 2 situations (88.9% of the amalgam restorations reported), while composite was most often placed in class 3, 4, or 5 situations (77.4% of the composite restorations reported). From the total data set returned for replaced restorations, only 20% of the data forms reported on verified longevity of the restoration being replaced. Analysis of these data gave a calculated median longevity for amalgam and composite restorations of 10 years and 5 years respectively.

Trends in clinical dentistry skills observed by board examiners: a 15-year comparison.

This study compares and analyzes the clinical performance of recent dental graduates over a 15-year period. A majority of the 981 board examiners, cumulatively surveyed, observed an increase in diagnosis/treatment planning and periodontal skills, and a decrease in operative and prosthodontic skills, while many other skills were performed at approximately the same level.

The effect of three finishing systems on four esthetic restorative materials.

Previous studies have investigated the finishing and smoothness of composite and traditional glass-ionomer restorations, but few have included resin-modified glass-ionomer cements or more recent finishing systems. The results of using three different finishing systems (Sof-Lex, Enhance, finishing burs) on two composites (Silux, Prisma TPH), a traditional glass ionomer (Ketac-Fil), and a resin-modified glass ionomer (Fuji II LC) were studied. Sixty samples were condensed into sectioned acrylic tubes, covered with a Mylar matrix plus a glass slide at each surface, then cured as per the manufacturers' instructions. Samples were randomized to three groups of five for each material and testing with a Surfanalyzer 4000 of unfinished samples (cured with Mylar matrix) was done to obtain baseline average surface roughness (Ra). Samples were then finished as per the manufacturers' instructions using polishing disks, abrasive impregnated disks, and finishing burs before further surface testing. Samples finished with burs and with abrasive impregnated disks were further polished using polishing paste (Prisma Gloss) and again tested. Data were analyzed with ANOVA testing and Tukey's HSD pairwise comparison. Initial testing after randomization to groups showed no significant difference in surface roughness (P = 0.24). Two-factor analysis revealed no significant difference between materials (P = 0.34), a significant difference in method of finish (P < or = 0.00), with no significant interaction between type of material and method of finish (P = 0.11). Aluminum oxide disk and impregnated disk systems provided the best finish for microfilled composite and both glass-ionomer materials (P < or = 0.00). No significant difference in method of finish existed with the hybrid composite (P = 0.07). Overall, esthetic restorative material finishing is best accomplished using abrasive impregnated disks or aluminum oxide disks. Finishing burs gave a significantly rougher surface than the former methods.

Effect of light source position and bevel placement on facial margin adaptation of resin-based composite restorations.

PURPOSE: To evaluate the effect of direction of first cure and the presence or absence of a facial margin bevel on the adaptation of facial margins of Class III resin-based composite (RBC) restorations. MATERIALS AND METHODS: Custom polyvinyl siloxane (PVS) light shields were fabricated for both the mesial and distal surfaces of 20 extracted incisors. Class III cavities were prepared in the mesial and distal surfaces of the incisors. On the facial, lingual, and gingival margins of 20 of the preparations a 0.5 mm wide enamel bevel was placed. The lingual and gingival, but not the facial, margins were beveled on the other 20 preparations. The PVS light shield was adapted to the tooth and trimmed to allow 1-2 mm of the facial margin to be exposed on 10 of the beveled and 10 of the non-beveled preparations. For the remaining 20 preparations the PVS light shield was trimmed to allow access of the curing light only from the lingual. Teeth were restored with Prisma TPH RBC. Using the appropriate shield, restorations in the facial first cure group were cured first from the facial and then from the lingual. Restorations in the lingual first cure group were cured only from the lingual. Restorations were finished flush with enamel margins and thermocycled following storage. Samples were exposed to a 50% solution of silver nitrate followed by light exposure. Teeth were sectioned and microleakage was evaluated at three levels (incisal, middle, and cervical). Four evaluators (blinded to direction of cure) independently scored microleakage using a categorical evaluation scale. Statistical analysis included non-parametric descriptive statistics, Cohen's kappa, chi-square analysis, and Kruskal-Wallis ANOVA. RESULTS: Samples prepared without a facial bevel revealed significantly more (P = 0.01) microleakage than preparations with a facial bevel. At the most incisal level, restorations cured first from the facial revealed significantly more (P < 0.001) microleakage than restorations cured first from the lingual. At the middle and cervical levels, restorations cured first from the facial revealed significantly less (P < 0.001) microleakage than restorations cured first from the lingual. When a facial bevel was present, samples cured first from the facial showed significantly less (P < 0.001) microleakage than those cured only from the lingual.

An in vitro investigation of the apical seal produced by a new thermoplasticized gutta-percha obturation technique.

This investigation quantitatively analyzed apical leakage in teeth in which one of two new thermoplasticized gutta-percha obturating techniques were used. Apical leakage observed after use of the thermoplasticized techniques was compared to leakage found in teeth that had been obturated with conventional lateral condensation. Statistically significant differences (P less than 0.05) were found among the three groups. The lateral condensation group exhibited the least leakage, followed by the thermoplasticized group, and the thermoplasticized twist-off group exhibited the most apical leakage.

Sugar substitutes in dental caries prevention. Significance of sorbitol and xylitol.

To date, effective caries prevention largely relies on the regular use of fluoride and oral hygiene. The potential efficacy of basing caries prevention on nutritional modifications has been suggested a long time ago. Subsequently, a great number of laboratory, animal and clinical investigations have convincingly demonstrated that partial substitution of sugar by noncariogenic sweeteners offers considerable benefits for dental health. This article reviews scientific information on sorbitol and xylitol, two caloric sugar substitutes that have been extensively studied with regard to their noncariogenic properties.

Post preparation techniques and their effect on the apical seal.

It is accepted clinical procedure to extend post preparations to such a depth that 3 mm to 5 mm of gutta-percha remains at the apex of the tooth. Clinicians use numerous techniques to achieve this goal. This investigation quantitatively analyzed the effect of the method of gutta-percha removal on the apical seal and evaluated apical leakage in teeth with different levels of remaining gutta-percha. The methods evaluated included the GPX instrument, heated pluggers, and Gates-Glidden drills. Groups of 25 extracted teeth were prepared with each of the three methods leaving 3 mm or 5 mm of gutta-percha remaining apically. Spectrophotometry (optical density) was used to assess apical leakage. Significantly less leakage was observed with the heated plugger technique at the 3 mm and 5 mm levels when compared to the 3 mm and 5 mm levels in both the GPX and Gates-Glidden groups.

Postoperative pain incidence related to the type of emergency treatment of symptomatic pulpitis.

Some endodontic emergencies occur as a result of attempts to relieve symptoms of pulpitis. The aim of this study was to identify any predictor of postoperative pain in a patient population treated by dental students. Patients who reported for treatment of symptomatic pulpitis were subjected to three different emergency treatment regimens. Clinical data was collected on those patients who reported in the emergency service with severe postoperative pain within 24 hours of emergency endodontic treatment. Statistical analysis of these data suggested that the type of endodontic emergency procedure carried out was a significant predictor of severe postoperative pain.

The Cytobrush Plus cell collector in oral cytology.

The Cytobrush Plus cell collector (cytobrush) was compared with the wooden tongue depressor during oral exfoliative cytology. The degree of patient discomfort, the convenience to the clinician, and the quantity and distribution of epithelial cells collected were evaluated. Two-factor analysis of variance and parametric and nonparametric analyses were performed. Because of the favorable findings revealed in this study, we recommend that the cytobrush be considered for use when obtaining diagnostic cytologic smears from the oral mucosa.