A small molecule, odanacatib, inhibits inflammation and bone loss caused by endodontic disease.

Periapical disease, an inflammatory disease mainly caused by dental caries, is one of the most prevalent infectious diseases of humans, affecting both children and adults. The infection travels through the root, leading to inflammation, bone destruction, and severe pain for the patient. Therefore, the development of a new class of anti-periapical disease therapies is necessary and critical for treatment and prevention. A small molecule, odanacatib (ODN), which is a cathepsin K (Ctsk) inhibitor, was investigated to determine its ability to treat this disease in a mouse model of periapical disease. While Ctsk was originally found in osteoclasts as an osteoclast-specific lysosomal protease, we were surprised to find that ODN can suppress the bacterium-induced immune response as well as bone destruction in the lesion area. X rays and microcomputed tomography (micro-CT) showed that ODN treatment had significant bone protection effects at different time points. Immunohistochemical and immunofluorescent staining show that ODN treatment dramatically decreased F4/80+ macrophages and CD3+ T cells in the lesion areas 42 days after infection. Consistent with these findings, quantitative real-time PCR (qRT-PCR) and enzyme-linked immunosorbent assay (ELISA) analysis showed low levels of proinflammatory mRNAs (for tumor necrosis factor alpha, interleukin 6, and interleukin 23α) and corresponding cytokine expression in the ODN-treated disease group. The levels of mRNA for Toll-like receptors 4, 5, and 9 also largely decreased in the ODN-treated disease group. Our results demonstrated that ODN can inhibit endodontic disease development, bone erosion, and immune response. These results indicate that application of this small molecule offers a new opportunity to design effective therapies that could prevent periapical inflammation and revolutionize current treatment options.

A residual granuloma in association with a dental implant.

At times, dental implants are placed into sites with a history of periapical pathology. Sometimes the infection is active, and other times the tooth may have been extracted years before implant placement. In either case, the possibility exists for long-term residual cysts or infections that can negatively impact the prognosis of the implant. In this case report, an implant is placed into a healed mandibular ridge several months after extraction of the tooth. A radiolucency was noted on routine radiographic examination 2 years later. Surgical inspection and histology revealed a periapical granuloma with acute and chronic inflammatory cells. After surgical curettage of the site, the patient healed without complication. Implants may develop apical pathology as a result of a preexisting long-term residual infection.

Comparison of the amount of transportation when using a precurved instrument in a sonic handpiece vs. nickel-titanium rotary files.

Three-dimensional cleaning of the root canal system along its basic shape is one of the main goals in endodontics. A sonic handpiece is a helpful adjunct that can aid in accomplishing this goal; however, its use has been limited due to the risk of transporting the apices' original position. Precurving sonic files may reduce transportation. For this study, 35 plastic blocks were randomly assigned to two groups, one of which (n = 16) was instrumented by nickel-titanium rotary files (to a size 40), while the second group (n = 18) was instrumented by a sonic handpiece with precurved files. Similar blocks were instrumented with noncurved sonic files and used as controls. Radiographs taken before and after instrumentation were compared. Of the 18 apices instrumented by the sonic handpiece with precurved files, seven were not transported. By comparison, 8 of the 16 apices instrumented by nickel-titanium files did not transport. When transportation did occur, it was less than 0.5 mm for either technique. The control blocks instrumented by the sonic handpiece with straight files were transported significantly. An ANOVA with a post hoc Tukey's test showed no statistically significant difference between the file systems. Based on the results, precurving sonic files to match the canal contour may allow for efficient cleaning without undue transportation.

Comparison of the success of root canal therapy in HIV/AIDS patients and non-infected controls.

This study compared the rate of successful endodontic treatments between two cohorts of patients with similar teeth, one group with HIV/AIDS and one without. A retrospective chart review was performed on two cohorts, with 50 teeth in each cohort. There was no statistically significant difference in endodontic success between the two groups. The failure groups were small, with no significant trends.

The effect of preoperative acetaminophen or a combination of acetaminophen and Ibuprofen on the success of inferior alveolar nerve block for teeth with irreversible pulpitis.

This study compared preoperative administration of acetaminophen or a combination of acetaminophen and ibuprofen versus placebo for potential increased effectiveness of inferior alveolar nerve (IAN) block anesthesia. There were 40 patients with irreversible pulpitis randomly assigned to a drug or placebo group. Thirty minutes after ingestion of medication, an IAN block was administered. A cold test was done 15 minutes after the block, and if the patients had no sensitivity, endodontic therapy was initiated. If the patient had no pain on access, the IAN was recorded as successful. If the patient had sensitivity to cold or to the access procedure, it was recorded as a failure. Overall success was 60% for all three groups. Success was 71.4% for the acetaminophen group, 75.9% for the acetaminophen and ibuprofen group, and 46.2% for the placebo group. There was no significant difference between the groups; however, there was a trend toward higher success in the medication groups.

16S Ribosomal RNA Gene Sequencing to Evaluate the Effects of 6 Commonly Prescribed Antibiotics.

INTRODUCTION: The rapid antibiotic sensitivity test (RAST) is a novel in-office culture and sensitivity system for endodontic infections. The purpose of this research was to validate the RAST system as a viable, in-office alternative to antibiotic sensitivity testing using turbidity to determine antibiotic sensitivities of endodontic infections. METHODS: Aspirates were taken from the root canals of 9 necrotic human teeth at the initiation of root canal therapy. These samples were cultured in the RAST medium, and antibiotic sensitivity to 6 antibiotics was tested. Further analysis was performed using 16S ribosomal RNA (rRNA) gene sequencing. RESULTS: Thirty-one bacterial phyla were identified as well as 2 phyla of the kingdom Archaea. Augmentin (Dr. Reddy's Laboratories Ltd, Hyderabad, India) and ampicillin performed identically at 24 hours, inhibiting turbidity in 100% of the samples. At 48 hours in anaerobic conditions, Augmentin outperformed ampicillin by 13%. Ciprofloxacin was the least efficacious antibiotic. At 48 hours, only 22% of anaerobic ciprofloxacin cultures affectively inhibited bacterial growth. CONCLUSIONS: The RAST medium is a viable in-office alternative to antibiotic susceptibility testing in an off-site laboratory. It is able to support the growth of a wide variety of microorganisms in both aerobic and anaerobic environments, and, in combination with 16S rRNA gene sequencing, it led to the identification of a new archaebacterial phylum, Crenarchaeota, as part of the endodontic infection microbiome.

Bacterial count comparisons on examination gloves from freshly opened boxes versus nearly empty boxes and from examination gloves before treatment versus after dental dam isolation.

Use of gloves in dentistry is primarily for protection of the healthcare worker, yet little information is available regarding potential patient issues such as microbial contamination of gloves before and during use. The purposes of this study were to compare gloves from newly opened boxes with those from boxes that had been in dental operatories until they were nearly empty and to determine if gloves are contaminated though diagnostic procedures and rubber dam placement. Eight endodontic residents provided samples by streaking gloved fingers on nutrient agar plates. Results showed no statistically significant difference between counts from new boxes versus nearly empty boxes (n = 32, p < 0.6216). Gloves after rubber dam placement yielded a mean colony count of 158 versus a 1.5 mean of fresh gloves (n = 64, p < 0.0001). These results suggest that the use of new gloves before opening a tooth for endodontic therapy may be warranted.

Cytotoxicity of a new root canal filling material on human gingival fibroblasts.

This study evaluated the cytotoxicity of the root canal sealing materials Resilon and Epiphany versus gutta-percha, Grossman's sealer, Thermaseal, and Sealapex. Using human gingival fibroblasts the fibroblasts cultures were incubated for either 1 or 24 h to test the cytotoxicity after freshly mixing or after 24 h of setting. Fibroblasts were then stained with trypan blue, to determine number of dead cells. Data were analyzed using ANOVA and t tests. Resilon was similar to gutta-percha and the control. Epiphany was less cytotoxic than Grossman's sealer at both the 1 and 24 h time periods. Epiphany was more cytotoxic than Sealapex at the 1-h time period but less cytotoxic at the 24 h time period. These results indicated that Resilon had a lower cytotoxicity and that Epiphany was more cytotoxic than conventional materials.

Elemental analysis of crystal precipitate from gray and white MTA.

Crystal growth and elemental dissolution characteristics of gray Mineral Trioxide Aggregate (GMTA), white MTA (WMTA), and an experimental material, Dentalcrete, were compared. For part A, comparing amount and composition of surface crystal growth, twelve cylinders of each material were suspended in Phosphate Buffered Saline (PBS) solution without Ca. The crystals were analyzed by Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), and Inductively Coupled Plasma--Atomic Emission Spectroscopy (ICP-AES). For part B, three cylinders of each material were suspended in distilled, deionized water. The water was analyzed by ICP-AES for Ca content at 24 h, 72 h, and 5, 7, 10, and 14 days. Data were analyzed using one-way ANOVA and Tukey test. Both MTA materials released more Ca initially, followed by a decline and then rise in elution. GMTA produced the most surface crystal, which may be clinically significant. The crystals on GMTA and WMTA were chemically and structurally similar to hydroxyapatite (HA).

Techniques and materials used by general dentists during endodontic treatment procedures: Findings from The National Dental Practice-Based Research Network.

BACKGROUND: Little is known about which materials and techniques general dentists (GDs) use during endodontic procedures. The objectives were to quantify GDs' use of specific endodontic tools, quantify inappropriate use, and ascertain whether inappropriate use is associated with GDs' practice characteristics. METHODS: GDs in The National Dental Practice-Based Research Network reported in a questionnaire materials and techniques they use during endodontic procedures. RESULTS: Among eligible GDs, 1,490 (87%) participated. Most (93%; n = 1,383) used sodium hypochlorite to irrigate. The most commonly used sealers were zinc oxide eugenol (43%) and resin (40%), followed by calcium hydroxide (26%). Most (62%; n = 920) used a compaction obturation technique; 36% (n = 534) used a carrier-based method. Most (96%; n = 1,423) used gutta-percha as a filler; 5% used paste fillers. Few used irrigants (n = 46), techniques (n = 49), or fillers (n = 10) that investigators classified as inappropriate. CONCLUSIONS: GDs use a broad range of endodontic techniques and materials, often adapting to newer technologies as they become available. Few GDs use tools that the investigators classified as inappropriate. PRACTICAL IMPLICATIONS: GDs use many types of endodontic techniques and materials, but only a small percentage of them are inappropriate.

A comparison of torque required to fracture rotary files with tips bound in simulated curved canal.

The purpose of this study was to compare torque force and rotation needed to fracture three types of nickel titanium alloy rotary instruments in a simulated curved root canal space that were bound at the file tip. Files of similar size tips were studied. The files studied were ProFiles with 0.04 taper diameters of 15, 20, 25, 30, 35, 40, 45; 0.04 ProFile GT sizes 20, 30, 40; and ProTaper files sizes S1, S2, F1, F2, and F3. All files were 25 mm in length. Unwinding was defined as the rotation in degrees it took for a file to fracture after the first evidence of permanent deformation. All files exhibited permanent deformation before breaking, with the ProFile GT files demonstrating the greatest unwinding. The #45 0.04 ProFile withstood the most force while the #20 ProFile GT required the least amount of force before beginning to exhibit permanent deformation. The S1 and S2 ProTaper files fractured with so little rotation that no extended data were recorded. Generally, as the file diameter increased, the force needed to begin unwinding also increased. Also, as the file diameter increased, the force needed to fracture also increased.

Analysis of heat generation using ultrasonic vibration for post removal.

This study measured the temperature of the root surface and post during the application of ultrasonic vibration to cemented posts to simulate post removal procedure. Root canal therapy was performed on ten extracted maxillary incisors. A stainless steel Parapost was cemented into each prepared post space. Ultrasonic vibration was applied to the post and temperatures were recorded at the coronal post and the cervical root surface. Data were analyzed with ANOVA using the independent variables of (a) time of ultrasonic application (15, 30, 45 and 60 s) and 2) location (post and root surface). Greater temperature increase was observed at the post (52.6 degrees C, SD 11.1; 82.6 degrees C, SD 20.1; 111.0 degrees C, SD 29.1; 125.3 degrees C, SD 33.2) compared to the root surface (9.5 degrees C, SD 4.6; 17.5 degrees C, SD 4.8; 25.4 degrees C, SD 7.3; 32.2 degrees C, SD 8.1) for each time period, P < 0.001. Ultrasonic application to the post for longer than 15 s generates high temperature on the root surface.

Discordance between presumed standard of care and actual clinical practice: the example of rubber dam use during root canal treatment in the National Dental Practice-Based Research Network.

OBJECTIVES: Use of a rubber dam during root canal treatment is considered the standard of care because it enhances patient safety and optimises the odds of successful treatment. Nonetheless, not all dentists use a rubber dam, creating disconnect between presumed standard of care and what is actually done in clinical practice. Little is known about dentists' attitudes towards use of the rubber dam in their practices. The objectives were to: (1) quantify these attitudes and (2) test the hypothesis that specific attitudes are significantly associated with rubber dam use. SETTING: National Dental Practice-Based Research Network (NationalDentalPBRN.org). PARTICIPANTS: 1490 network dentists. OUTCOME MEASURES: Dentists completed a questionnaire about their attitudes towards rubber dam use during root canal treatment. Three attitude scales comprised 33 items that used a 5-point ordinal scale to measure beliefs about effectiveness, inconvenience, ease of placement, comparison to other isolation techniques and patient factors. Factor analysis, cluster analysis and multivariable logistic regression analysed the relationship between attitudes and rubber dam use. RESULTS: All items had responses at each point on the 5-point scale, with an overall pattern of substantial variation across dentists. Five attitudinal factors (rubber dam effectiveness; inconvenient/time-consuming; ease of placement; effectiveness compared to Isolite; patient factors) and 4 clusters of practitioners were identified. Each factor and cluster was independently and strongly associated with rubber dam use. CONCLUSIONS: General dentists have substantial variation in attitudes about rubber dam use. Beliefs that rubber dam use is not effective, inconvenient, time-consuming, not easy to place or affected by patient factors, were independently and significantly associated with lower rubber dam use. These attitudes explain why there is substantial discordance between presumed standard of care and actual practice.

General Dentists' Use of Isolation Techniques during Root Canal Treatment: From the National Dental Practice-based Research Network.

INTRODUCTION: A preliminary study done by a National Dental Practice-Based Research Network precursor observed that 44% of general dentists (GDs) reported always using a rubber dam (RD) during root canal treatment (RCT). This full-scale study quantified the use of all isolation techniques, including RD use. METHODS: Network practitioners completed a questionnaire about isolation techniques used during RCT. Network enrollment questionnaire data provided practitioner characteristics. RESULTS: One thousand four hundred ninety of 1716 eligible GDs participated (87%); 697 (47%) reported always using an RD. This percentage varied by tooth type. These GDs were more likely to always use an RD, do not own a private practice, perform less than 10 RCTs/month, and have postgraduate training. CONCLUSIONS: Most GDs do not use an RD all the time. Ironically, RDs are used more frequently by GDs who do not perform molar RCT. RD use varies with tooth type and certain dentist, practice, and patient characteristics.

Evaluation of ciprofloxacin and metronidazole encapsulated biomimetic nanomatrix gel on Enterococcus faecalis and Treponema denticola.

BACKGROUND: A triple antibiotic mixture (ciprofloxacin; CF, metronidazole; MN, and minocycline; MC) has been used for dental root canal medicaments in pulp regeneration therapy. However, tooth discolorations, cervical root fractures, and inadequate pulp-dentin formation have been reported due to the triple antibiotic regimen. Therefore, an antibiotic encapsulated biomimetic nanomatrix gel was developed to minimize the clinical limitations and maximize a natural healing process in root canal infections. In this study, minimal bacterial concentrations (MBC) of the selected antibiotics (CF and MN) were tested in 14 representative endodontic bacterial species. Then MBC of each CF and MN were separately encapsulated within the injectable self-assembled biomimetic nanomatrix gel to evaluate antibacterial level on Enterococcus faecalis and Treponema denticola. RESULTS: Antibiotic concentrations lower than 0.2 µg/mL of CF and MN demonstrated antibacterial activity on the 14 endodontic species. Furthermore, 6 different concentrations of CF and MN separately encapsulated with the injectable self-assembled biomimetic nanomatrix gel demonstrated antibacterial activity on Enterococcus faecalis and Treponema denticola at the lowest tested concentration of 0.0625 µg/mL. CONCLUSIONS: These results suggest that each CF and MN encapsulated within the injectable self-assembled biomimetic nanomatrix gel demonstrated antibacterial effects, which could be effective for the root canal disinfection while eliminating MC. In the long term, the antibiotic encapsulated injectable self-assembled biomimetic nanomatrix gel can provide a multifunctional antibiotic delivery method with potential root regeneration. Further studies are currently underway to evaluate the effects of combined CF and MN encapsulated within the injectable self-assembled biomimetic nanomatrix gel on clinical samples.

Objective measurement of patient's dental anxiety by galvanic skin reaction.

The purpose of this study was to determine if anxiety can be measured objectively by skin conductance of a weak electric current. Three measurements were taken. First, a standardized dental-anxiety questionnaire was given to determine anxiety. Second, galvanic skin conductance was measured. Third, polygraph responses were recorded to three key questions from the questionnaire. Questionnaire scores of these key questions were used to create two groups: anxious and not-anxious. The three key questions were subjected to polygraph verification. In the first analysis patients were excluded if the polygraph test disclosed lying on any of the three key questions. The second analysis excluded liars on a question-by-question basis. The third analysis disregarded the polygraph. A statistically significant correlation was found between skin conductance and dental anxiety in all cases. Data seem to indicate that fear of injection is the most anxiety-producing aspect of modern dentistry.

Effect of a separated instrument on bacterial penetration of obturated root canals.

The aim of this study was to determine the effect a separated instrument has on the time required for bacterial penetration of obturated root canals. Twenty-six extracted human mandibular premolars with single canals were used in the study. Group 1 consisted of teeth that contained a separated size 40 Profile rotary file and were obturated with gutta-percha and zinc oxide eugenol sealer to the level of the separated file. Group 2 consisted of teeth that were similarly obturated, but without a separated file. The negative control canals were obturated and had the entire root surface sealed with nail polish. The positive controls were obturated without sealer. Streptococcus sanguis was placed in the access chamber daily, and penetration was determined when turbidity was noted in the culture broth. The results showed no significant difference between the two experimental groups.

The effect of three commonly used endodontic materials on the strength and hardness of root dentin.

The purpose of this study was to determine if calcium hydroxide, mineral trioxide aggregate, or sodium hypochlorite caused a change in the force required to fracture root dentin. Ten bovine central and lateral incisors were machined using various saws and drills to produce a cylinder of dentin with a 6.0-mm outer diameter 3.5-mm inner diameter and a length of 10 mm. The cylinders were cut lengthwise into four symmetrical pieces. The canal sides of the sections were then placed into Petri dishes containing a 1-mm depth of calcium hydroxide, mineral trioxide aggregate, sodium hypochlorite, or physiologic saline (control). The samples remained in the dishes for 5 weeks and were then shear tested by using an Instron machine. Data were analyzed using an ANOVA test for comparison of the groups as a whole, and a t test was used to compare each quarter section with its control from the same tooth. A 32% mean decrease in strength was discovered for calcium hydroxide, a 33% decrease in strength for mineral trioxide aggregate, and a 59% decrease for sodium hypochlorite. All decreases in strength were statistically significant: p < 0.001 for calcium hydroxide, p = 0.027 for mineral trioxide aggregate, and p < 0.001 for sodium hypochlorite. Results indicated that root dentin was weakened after 5 weeks of exposure to calcium hydroxide, mineral trioxide aggregate, or sodium hypochlorite.

A comparison of torque required to fracture three different nickel-titanium rotary instruments around curves of the same angle but of different radius when bound at the tip.

Instrument fracture is an unfortunate but possible sequela of instrumentation of canals, especially when the instrument is bound at the tip. The purpose of this study was to compare the torque required to fracture three file sizes of three different rotary file types around two simulated canal curvatures, gradual or acute, when the tip of the working end of the file was bound. Profile Series 29 0.04 and 0.06 taper and Profile 0.06 ISO rotary files were placed passively into simulated canal curvatures of the same angle but of different radii. The file tips were bound 2 mm from the working end and a measurable torque was applied until fracture. ANOVA with Tamhane post-hoc comparison showed that the 0.06 Series 29 did not differ from the ISO 0.06 taper or the 0.04 Series 29 but there was statistical difference (p < 0.01) showing that the 0.04 Series 29 broke with less force than did the 0.06 ISO files. Statistical tests (p < 0.01) also showed smaller files failed with less torque, as did files in more acute canal curvatures.

Comparison of endodontist versus generalist regarding preference for postendodontic use of cotton pellets in pulp chamber.

A degree of uncertainty exists about the use of cotton pellets in the pulp chamber after canal obturation. The purpose of this study was to poll practicing endodontists and generalists regarding their preference. Forty-six endodontists and an equal number of general dentists were polled in a mail survey regarding their preferences for the use of a cotton pellet in the pulp chamber after canal obturation. Eighty-seven percent of the endodontists and 54% of the generalists responded. Of the endodontists, 62.5% said they thought that the general dentist wanted a cotton pellet, contrasted to 80% of the generalists. The difference in proportions was not statistically significant.