Francesco Mannocci

Detection of periapical bone defects in human jaws using cone beam computed tomography and intraoral radiography

AIM To compare the diagnostic accuracy of intraoral digital periapical radiography with that of cone beam computed tomography (CBCT) for the detection of artificial periapical bone defects in dry human jaws. METHODOLOGY Small and large artificial periapical lesions were prepared in the periapical region of the distal root of six molar teeth in human mandibles. Scans and radiographs were taken with a charged couple device (CCD) digital radiography system and a CBCT scanner before and after each periapical lesion had been created. Sensitivity, specificity, positive predictive values, negative predictive values and Receiver Operator Characteristic (ROC) curves as well as the reproducibility of each technique were determined. RESULTS The overall sensitivity was 0.248 and 1.0 for intraoral radiography and CBCT respectively, i.e. these techniques correctly identified periapical lesions in 24.8% and 100% of cases, respectively. Both imaging techniques had specificity values of 1.0. The ROC Az values were 0.791 and 1.000 for intraoral radiography and CBCT, respectively. CONCLUSIONS With intraoral radiography, external factors (i.e. anatomical noise and poor irradiation geometry), which are not in the clinicians control, hinder the detection of periapical lesions. CBCT removes these external factors. In addition, it allows the clinician to select the most relevant views of the area of interest resulting in improved detection of the presence and absence of artificial periapical lesions.

Diagnostic accuracy of small volume cone beam computed tomography and intraoral periapical radiography for the detection of simulated external inflammatory root resorption

AIM To compare in an ex vivo model the ability of digital intraoral radiography and cone beam computed tomography (CBCT) to detect simulated external inflammatory root resorption lesions, and to investigate the effect of altering the degree of rotation of the CBCT scanners X-ray source and imaging detector on the ability to detect the same lesions. METHODOLOGY Small and large simulated external inflammatory resorption (EIR) lesions were created on the roots of 10 mandibular incisor teeth from three human mandibles. Small volume CBCT scans with 180° and 360° of X-ray source rotation and periapical radiographs, using a digital photostimulable phosphor plate system, were taken prior to and after the creation of the EIR lesions. The teeth were relocated in their original sockets during imaging. Receiver operator characteristic (ROC) analysis and kappa tests of the reproducibility of the imaging techniques were carried out and sensitivity, specificity, positive and negative predictive values (PPV and NPV) were also determined for each technique. RESULTS The overall area under the ROC curve (Az value) for intraoral radiography was 0.665, compared to Az values of 0.984 and 0.990 for 180° and 360° CBCT, respectively (P<0.001). The sensitivity and specificity of 180° and 360° CBCT were significantly better than intraoral radiography (P<0.001). CBCT, regardless of the degree of rotation, had superior NPVs (P<0.01) and PPVs (P<0.001) to periapical radiography. The intra- and inter-examiner agreement was significantly better for CBCT than it was for intraoral radiography (P<0.001). The ability of small volume CBCT to detect simulated EIR was the same regardless of whether 180° or 360° scans were taken. Examiners were significantly better able to identify the exact location of the artificial resorption lesions with CBCT than they were with periapical radiographs (P<0.001). CONCLUSION CBCT is a reliable and valid method of detecting simulated EIR and performs significantly better than intraoral periapical radiography. Small volume CBCT operating with 360° of rotation of the X-ray source and detector is no better at detecting small, artificially created EIR cavities than the same device operating with 180° of rotation.

Three-point bending test of fiber posts

Five different types of fiber posts (carbon fiber Composipost radio-opaque, quartz fiber Aestheti-Plus, carbon fiber Carbotech, glass fiber Light post, and silica fiber Snowpost) were submitted to a three-point bending test after being stored for 1 yr under three different conditions: dry storage at room temperature, storage in 37 degrees C water, and storage in bovine teeth that were endodontically treated and restored with composite resin. The posts were observed before and during the test by confocal microscopy. More voids were found within the Composipost radio-opaque than in other posts. Posts of all groups that were stored in water showed flexural strength values lower than posts that were stored dry. In all storage conditions, Carbotech posts showed higher flexural strength values than Composiposts and Snowposts, and Aestheti-Plus posts showed higher flexural strength values than Snowposts. Posts that were stored in bovine teeth showed flexural strength values similar to those of posts that were stored dry. It was concluded that fiber posts must not be in contact with oral fluids and that during the 1-yr storage in bovine teeth, they were sufficiently protected from this contact by the apical root canal filling and by the coronal composite resin filling.

The detection of periapical pathosis using periapical radiography and cone beam computed tomography - Part 1: pre-operative status

AIM Part 1 of this 2 part study aims to compare the prevalence of periapical lesions on individual roots viewed with intraoral (periapical) radiographs and cone-beam computed tomography (CBCT) of teeth treatment planned for endodontic treatment. METHODOLOGY Diagnostic periapical radiographs and CBCT scans were taken of 151 teeth in 132 patients diagnosed with primary endodontic disease. The presence or absence of periapical lesions was assessed by a consensus panel consisting of two calibrated examiners, a consensus agreement was reached if there was any disagreement. The panel viewed the images under standardised conditions. Part 2 will compare the radiographic outcome 1 year after completion of primary root canal treatment. RESULTS Two hundred and seventy-three paired roots were assessed with both radiological systems, periapical lesions were present in 55 (20%) and absent in 218 (80%) roots assessed with periapical radiographs. When the same 273 sets of roots were assessed with CBCT, lesions were present in 130 (48%) and absent in 143 (52%) roots. Seventy-five additional roots were detected with CBCT. CONCLUSION The limitations of periapical radiographs which may hinder the detection of periapical lesions are overcome with CBCT. This results in firstly, more roots being assessed, and secondly, more periapical lesions being detected with CBCT.

Density of dentinal tubules affects the tensile strength of root dentin

OBJECTIVES The aim of this study is to count the dentinal tubules in the coronal and middle-apical third of root dentin of teeth extracted due to the progression of periodontal disease, and to compare the Ultimate Tensile Strength (UTS) of the same areas. The research hypothesis was that root dentin areas with different densities of dentinal tubules would also show different UTS values. METHODS From 10 caries free maxillary central, lateral incisors and canines, extracted for periodontal reasons from three patients, cylindrical specimens approximately 10 mm long were prepared parallel to the long axis of the root and then divided into two parts using a low speed diamond saw one from the coronal third of the root, (Group 1) and one from the middle-apical third of the root (Group 2). The density of the dentinal tubules of the specimens of the two groups was measured by means of a scanning electron microscope and the UTS of the specimens was measured by a microtensile test. One way ANOVA was used to assess the effect of specimen location (coronal specimens vs. middle-apical specimens) on UTS. The differences in the density of dentinal tubules between coronal and middle-apical specimens were also subjected to statistical analysis using one-way ANOVA. RESULTS UTS values of middle-apical specimens were found to be significantly (p < 0.05) higher than those of coronal specimens. The results of the one-way analysis of variance showed that the number of dentinal tubules of the samples from the coronal part of the root groups was significantly higher than that of samples from the middle-apical part (p < 0.05). SIGNIFICANCE These results suggest that high values of tensile strength of the dentin are associated with low densities of dentinal tubules and that apical areas of root dentin are more resistant to tension than coronal ones.

Apical seal of roots obturated with laterally condensed gutta-percha, epoxy resin cement, and dentin bonding agent.

The apical seal of roots obturated with either of two kinds of dentin bonding agent, gutta-percha and epoxy-resin-based root canal sealer, was compared by a die leakage test with that of an epoxy resin root canal sealer and gutta-percha without a bonding agent. Thirty-two roots were prepared chemomechanically and divided into three experimental groups. Group 1 was filled with gutta-percha, epoxy-resin sealer, and All-Bond 2 Adhesive. Group 2 was filled with gutta-percha, epoxy-resin sealer, and Scotchbond Multi-Purpose Plus adhesive. Group 3 was filled with gutta-percha and epoxy resin sealer. The teeth were immersed in 2% methylene blue solution. Groups 1 and 2 leaked significantly less than group 3. The materials most frequently observed at the apex were in group 1 dental adhesive and in group 2 gutta-percha. The interface between dentin and the adhesive materials in groups 1 and 2 was examined by scanning electron microscope and showed a hybrid-like layer.

Micropermeability of current self-etching and etch-and-rinse adhesives bonded to deep dentine: a comparison study using a double-staining/confocal microscopy technique

Water sorption decreases the mechanical properties and the bond strengths of resin-bonded dentine. The aim of this study was to evaluate the micropermeability of several self-etching and etch-and-rinse adhesives. Optibond FL, Silorane, Scotchbond 1XT, G-Bond, and DC-Bond were bonded under simulated pulpal pressure. A 10 wt% solution of ammoniacal silver nitrate and a 1 wt% solution of rhodamine B were injected into the pulp chamber at 20 cm of water pressure. The dentine-adhesive interfaces were examined using a confocal scanning microscope. Micropermeability was detected in all the adhesives. DC-Bond, G-Bond, and Scotchbond 1XT showed voids along the resin-bonded interface. Silorane and Optibond FL showed an adhesive layer that was free from water trees and micropermeability. The double staining technique is a method that gives accurate results in the study of the resin-dentine micropermeability. Each class of adhesive has a different distribution of micropermeability. The higher the micropermeability, the higher the risk of defects at the resin-dentine interface, which may represent the pathway for hydrolytic and enzymatic degradation of resin-dentine bonds over time.

Propionibacterium acnes and Staphylococcus epidermidis Isolated from Refractory Endodontic Lesions Are Opportunistic Pathogens

ABSTRACT The predominant cultivable microbiota from 20 refractory endodontic lesions (9 with abscesses and 11 without abscesses) were determined, and Propionibacterium acnes and Staphylococcus epidermidis were among the most predominant organisms. The number of species identified from lesions with abscesses (14.1 ± 2.6) was significantly greater (P < 0.001) than the number from lesions without abscesses (7.4 ± 5.9). Comparison of perioral isolates using repetitive extragenic palindromic PCR of the same species from the same subjects demonstrated that the endodontic and skin populations were significantly different. The P. acnes isolates were typed on the basis of recA gene sequence comparison, and only three types (types I, II, and III) were identified among 125 isolates examined. However, we found that type I (type IA and IB) isolates were primarily isolated from the skin, while types II and III were significantly more likely to be isolated from the endodontic lesions (P < 10−10). We found that the robustness of the recA phylotypes was not strong by comparing the partial gene sequences of six putative virulence determinants, PAmce, PAp60, PA-25957, PA-5541, PA-21293, and PA-4687. The resulting neighbor-joining trees were incongruent, and significant (phi test; P = 2.2 × 10−7) evidence of recombination was demonstrated, with significant phylogenetic heterogeneity being apparent within the clusters. P. acnes and S. epidermidis isolated from refractory endodontic infections, with or without periapical abscesses, are likely to be nosocomial infections.

Two-Photon Laser Confocal Microscopy of Micropermeability of Resin-Dentin Bonds Made With Water or Ethanol Wet Bonding

This study evaluated the micropermeability of six etch-and-rinse adhesives bonded to dentin. There were two principal groups: wet bonding with water or wet bonding with absolute ethyl alcohol. After bonding and the creation of composite build-ups, the pulp chambers were filled with 0.1% lucifer yellow. The contents of the pulp chamber were kept under 20 cm H(2)O pressure to simulate pulpal pressure for 3 h. The specimens were vertically sectioned into multiple 0.5-mm thick slabs that were polished and then examined using a two-photon confocal laser scanning microscope (TPCLSM). The results showed that specimens bonded with adhesives using the water wet-bonding condition all showed tracer taken up uniformly by the hybrid layer. This uptake of fluorescent tracer into the hybrid layer was quantified by computer software. The most hydrophobic experimental resins showed the highest fluorescent tracer uptake (ca. 1800 +/- 160 arbitrary fluorescent units/std. surface area). The most hydrophilic experimental resins showed the lowest tracer uptake into water-saturated hybrid layers. When ethanol wet-bonding was used, significantly less fluorescent tracer was seen in hybrid layers. The most hydrophilic experimental resins and Single Bond Plus showed little micropermeability. Clearly, ethanol wet-bonding seals dentin significantly better than water-wet dentin regardless of the adhesive in etch-and-rinse systems.

The effectiveness of passive ultrasonic irrigation on intraradicular Enterococcus faecalis biofilms in extracted single‐rooted human teeth

AIM To compare the efficacy of passive ultrasonic irrigation with 1% sodium hypochlorite, with that of conventional syringe irrigation with 1% sodium hypochlorite, on intraradicular Enterococcus faecalis biofilms in extracted single-rooted human teeth. METHODOLOGY Biofilms of E. faecalis (strain OMGS 3202) were grown on the prepared root canal walls of 48 standardized root halves which had been longitudinally sectioned. Following reapproximation, the roots were divided into four groups of twelve. The two experimental groups were treated with conventional syringe irrigation with 1% sodium hypochlorite solution (experimental group A) and passive ultrasonic irrigation with 1% sodium hypochlorite solution (experimental group B). Of the two control groups, the first was treated with conventional syringe irrigation with sterile saline solution (control group C), whilst the second control group (D) received no irrigation. The root halves were processed for scanning electron microscopy. Three images (x 700), coronal, middle and apical, were taken of the twelve root halves in each of the four groups, using a standardized protocol. The images were randomized and biofilm coverage assessed independently by three calibrated examiners, using a four-point scoring system. RESULTS There were no significant differences in the scores for remaining biofilm coverage between group A (conventional syringe irrigation with 1% sodium hypochlorite) and group B (passive ultrasonic irrigation with 1% sodium hypochlorite) at the three observed levels. There was a significant difference between both experimental groups (groups A and B) and group C (conventional syringe irrigation with sterile saline solution) (P < 0.001) at all three observed levels. CONCLUSIONS Both conventional syringe irrigation and passive ultrasonic irrigation with 1% sodium hypochlorite were effective at completely removing intraradicular E. faecalis biofilms. Conventional syringe irrigation with sterile saline solution was only partially effective at removing the biofilms.