An evaluation of bacterial contamination of barriers used in periapical tissue regeneration: Part 2--Bacterial penetration.

OBJECTIVE: To compare the relative penetration of Prevotella melaninogenica and Enterococcus faecalis through 3 guided tissue regeneration membranes: Atrisorb, Lambone, and OsseoQuest. It was hypothesized that OsseoQuest would show increased bacterial penetration when compared to Lambone and Atrisorb. METHOD AND MATERIALS: Centrifuge tubes containing trypticase soy broth were sealed with circular sections of membranes and placed in test tubes containing culture media. The bacterial penetration was assessed by passage of bacteria from the outer tube culture media to the inner centrifuge tube media through the membrane. After incubation for 4 and 48 hours, the media from the outer and inner tubes were compared for bacterial count. RESULTS: P melaninogenica exhibited 91% penetration for Lambone in 2 days, while OsseoQuest displayed 87% penetration with E faecalis in the same time. Atrisorb displayed a minimal penetration with both bacteria (2%). CONCLUSION: Atrisorb displayed the least bacterial penetration, which may be attributed to membrane structure, chemical configuration, hydrophobicity, and porosity of tested membranes.

An evaluation of bacterial contamination of barriers used in periapical tissue regeneration: Part 1--Bacterial adherence.

OBJECTIVE: To compare the adherence of Prevotella melaninogenica and Enterococcus faecalis to 3 guided tissue regeneration membranes: Atrisorb, Lambone, and OsseoQuest. It was hypothesized that OsseoQuest would show increased bacterial adherence compared to Lambone and Atrisorb. METHOD AND MATERIALS: The barriers were suspended in trypticase soy broth containing an inoculum of either P melaninogenica or E faecalis. The samples were incubated under appropriate conditions for 6, 24, and 48 hours. Following incubation, each membrane was mixed in fresh media in a vortex machine to dislodge adherent bacteria. The vortexed media was quantitatively assessed using serial dilutions for viable cell count. RESULTS: E faecalis exhibited higher adherence compared to P melaninogenica with time. Of the membranes tested, Lambone displayed the least bacterial adherence. CONCLUSION: An analysis of the results indicated that bacterial adherence was time-dependent for all membranes. Membrane structure, chemical configuration, hydrophobicity, and bacterial cell surface structure were suggested as factors contributing to variance in bacterial adherence.

Intracanal assessment of mineral trioxide aggregate setting and sealing properties.

This study sought to assess setting time and sealing properties of intracanal mineral trioxide aggregate (MTA). Eighty-three extracted single-rooted human teeth were decoronated and instrumented using the crown-down technique. The apical 3.0 mm of each tooth was resected. After MTA was placed, the coronal openings of the canals were sealed with moist cotton pellets. Root samples were divided into three groups according to setting time periods of four hours, two days, or one week. Within each group, 15 samples were kept in wet gauze to provide a moist apical environment (WA) while the remaining 10 were kept in a dry apical environment (DA). After respective incubation periods, 20 samples per group (10 WA, 10 DA) were mounted in an apical broth turbidity determination chamber and incubated for 30 days. The remaining five teeth per group (WA-h) were sectioned into 3.0 mm slices and compared for MTA setting hardness using the Shore-D Hardness test. Remaining teeth served as negative and positive controls. Each sample was inoculated coronally with Enterococcus faecalis and checked daily for turbidity in apical broth. Microbial leakage was reduced significantly as setting time increased from four hours to two days or one week. There was no significant reduction in leakage when setting time was increased from two days to one week. Over the first 20 days, the DA samples showed a higher rate of leakage compared to the WA samples. The Shore-D hardness test correlated with leakage results; 93% of total setting hardness was reported at two days and one week compared to only 75% for the four-hour group. Results suggest that apical moisture may affect MTA setting time or sealing ability initially and that intracanal MTA may take up to two days to set completely.

The role of apical size determination and enlargement in the reduction of intracanal bacteria.

The master apical preparation size in root canal therapy is debatable despite considerable research. The present study compared file sizes that bind at the apex before and during crown-down preparation and assessed the relation between apical size and extent of intracanal bacterial load. There were 100 single-rooted teeth biomechanically prepared after inoculation with Enterococcus faecalis. Canals were preflared, and apical size was ascertained by the first file to bind (FAB) at the working length (WL). During crown-down preparation, the first crown-down file to reach the apex during instrumentation was noted (CDF). Teeth were then divided into three master apical file size groups of CDF + 1, CDF + 2, and CDF + 3. Positive controls were inoculated postinstrumentation, whereas negative controls were instrumented without inoculation (n = 5). The samples were then cultured for intracanal bacterial counts. Fifteen samples and four controls were analyzed under SEM. The data were analyzed using ANOVA, Student's t-test, and chi(2) tests. The CDF was demonstrated to be an average of four file sizes larger than the FAB (p < 0.05). There was a significant increase in the number of samples with negative cultures from CDF + 1 to CDF + 3. SEM observation revealed bacteria on dentinal walls and in tubules even in most negative canal cultures.

An analysis of current analgesic preferences for endodontic pain management.

A descriptive, cross sectional survey was developed to determine the preferences of endodontists when prescribing analgesics. Eleven clinical scenarios describing common endodontic diagnoses or procedures with specified severity of pain were provided. A survey was sent to 310 AAE members and 63 responded, providing a 20% response rate. Respondents were given various choices for analgesic prescription including various dosages of ibuprofen or acetaminophen (APAP), or combination narcotic medications. Data were analyzed by chi2 tests. Non-narcotics were preferred over narcotics for all clinical situations. Significantly more respondents selected ibuprofen 600 mg (4x a day) regardless of the severity of preoperative or postoperative pain (p<0.001). Educators and board-certified AAE members were less likely than nonboard certified AAE members to manage their patient's perceived severe pain with narcotic analgesics.

Electric pulp tester conductance through various interface media.

A conducting media is necessary when using an electric pulp tester (EPT). The objective of this study was to observe differences in conductance through various media. We hypothesized that variations in current conductance through different media exist. The pulp chamber of a freshly extracted premolar was exposed, and the cathode of a voltmeter was inserted into the pulpal tissue. The anode was coupled to the EPT handpiece. The measurement taken during dry (no interface media) EPT tip-to-tooth contact was 0 V, which served as negative control. EPT tip directly touching the cathode measured 3.9V and served as positive control. A number of media readily available in the dental office were tested. Data was analyzed using single factor ANOVA. Listerine (3.3) conducted the most voltage (p<0.5). Of nonliquids, K-Y Brand UltraGel and Crest Baking Soda & Peroxide Whitening Tartar Control toothpaste recorded significantly (p<0.05) higher voltage readings (1.4 V).

Endodontic treatment in an American Indian population: a 10-year retrospective study.

An epidemiological study of a regional population of Native Americans receiving treatment from 1991 to 2000 (n = 5460) was conducted via electronic survey. The objectives were to identify factors affecting the retention of endodontically treated teeth and to determine frequencies of endodontic care. Multiple factors were assessed. Analyses utilized chi(2) and frequency tests. The results indicated that endodontists tend to complete most posterior teeth and retreatment cases, while generalists tended to complete anterior teeth, primary endodontic therapy, and to restore immediately. Patients with multiple systemic diseases (p = 0.0225) and diabetes (p < 0.0001) experienced decreased retention of endodontically treated teeth and increased retreatment (p = 0.0109) by endodontists. Patients treated by general dentists experienced increased retention for female patients (p = 0.0066), immediate restoration of the treated tooth (p = 0.0212), and decreased retention with a history of hypertension (p = 0.0036) and diabetes (p = 0.0033). This study suggests that diabetes and/or hypertension, delayed or no restoration, and increasing age, may all contribute to decreased retention of endodontically treated teeth, but that immediate postendodontic restoration may enhance retention. In the early era, very few cases of molar endodontics were completed, and one could infer that there were greater numbers of posterior teeth extracted because of this fact. This demonstrates how a combination of providers can provide a broader range of clinical endodontic services, supporting an Indian Health Service goal of providing the highest level of oral health care possible.

Evaluation of cutting efficiency of ultrasonic tips used in orthograde endodontic treatment.

The purpose of the present study was to evaluate the cutting efficiency of the three different ultrasonic tips for orthograde endodontic treatment: stainless steel, zirconium nitride-coated, and diamond-coated tips. An ultrasonic handpiece was mounted on a custom-made automated balance, and each tip repeatedly penetrated dental stone blocks to a depth of 3 mm for 10 times. The amount of time taken to penetrate 3 mm of stone was measured. The diamond-coated tips showed significantly greater cutting efficiency than either stainless steel tips or zirconium-nitride coated tips. The stainless steel tips showed initial better cutting efficiency, but over time , there is no significant difference between the cutting efficiency of the stainless steel tips and the zirconium nitride coated tips. The diamond coated tips were the only group that showed breakage in this study.

Decolorization of malachite green and crystal violet by waterborne pathogenic mycobacteria.

Mycobacterium avium, Mycobacterium intracellulare, Mycobacterium scrofulaceum, Mycobacterium marinum, and Mycobacterium chelonae tolerate high concentrations of the dyes malachite green and crystal violet. Cells of strains of those species decolorized (reduced) both malachite green and crystal violet. Because decolorized malachite green lacked antimicrobial activity, the resistance of these mycobacteria could be due, in part, to their ability to decolorize the dyes. Small amounts of malachite green and its reduced, decolorized product were detected in the lipid fraction of M. avium strain A5 cells grown in the presence of malachite green, suggesting that a minor component of resistance could be due to sequestering the dyes in the extensive mycobacterial cell surface lipid. The membrane fraction of M. avium strain A5 had at least a fivefold-higher specific decolorization rate than did the crude extract, suggesting that the decolorization activity is membrane associated. The malachite green-decolorizing activity of the membrane fraction of M. avium strain A5 was abolished by either boiling or proteinase exposure, suggesting that the decolorizing activity was due to a protein. Decolorization activity of membrane fractions was stimulated by ferrous ion and inhibited by dinitrophenol and metyrapone.