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The overexpression of the prostate cancer antigen 3 (PCA3) gene is well-defined as a marker for prostate cancer (PCa) diagnosis. Although widely used in clinical research, PCA3 molecular mechanisms remain unknown. Herein we used phage display technology to identify putative molecules that bind to the promoter region of PCA3 gene and regulate its expression. The most frequent peptide PCA3p1 (80%) was similar to the Rho GTPase activating protein 21 (ARHGAP21) and its binding affinity was confirmed using Phage Bead ELISA. We showed that ARHGAP21 silencing in LNCaP prostate cancer cells decreased PCA3 and androgen receptor (AR) transcriptional levels and increased prune homolog 2 (PRUNE2) coding gene expression, indicating effective involvement of ARHGAP21 in androgen-dependent tumor pathway. Chromatin immunoprecipitation assay confirmed the interaction between PCA3 promoter region and ARHGAP21. This is the first study that described the role of ARHGAP21 in regulating the PCA3 gene under the androgenic pathway, standing out as a new mechanism of gene regulatory control during prostatic oncogenesis.

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The overexpression of the prostate cancer antigen 3 (PCA3) gene is well-defined as a marker for prostate cancer (PCa) diagnosis. Although widely used in clinical research, PCA3 molecular mechanisms remain unknown. Herein we used phage display technology to identify putative molecules that bind to the promoter region of PCA3 gene and regulate its expression. The most frequent peptide PCA3p1 (80%) was similar to the Rho GTPase activating protein 21 (ARHGAP21) and its binding affinity was confirmed using Phage Bead ELISA. We showed that ARHGAP21 silencing in LNCaP prostate cancer cells decreased PCA3 and androgen receptor (AR) transcriptional levels and increased prune homolog 2 (PRUNE2) coding gene expression, indicating effective involvement of ARHGAP21 in androgen-dependent tumor pathway. Chromatin immunoprecipitation assay confirmed the interaction between PCA3 promoter region and ARHGAP21. This is the first study that described the role of ARHGAP21 in regulating the PCA3 gene under the androgenic pathway, standing out as a new mechanism of gene regulatory control during prostatic oncogenesis.

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Leishmaniasis is an anthropozoonosis transmitted by vectors, with dogs being the main domestic reservoirs. Brazil is one of the countries most affected by this disease, and it has been described in humans and dogs in every region in the country. In the northern region leishmaniasis cases in humans have been described in more than 100 municipalities in the State, including the capital, Belém. This study involves two cases of canine visceral leishmaniasis in which the animals developed clinical signs compatible with the disease in urban areas in Belém, the Pará state capital. The diagnosis was confirmed via polymerase chain reaction (PCR) to detect SSUr-rDNA and kDNA of Leishmania sp. and Leishmania infantum, respectively. In one of the cases the animal died and in the other the animal underwent treatment with medicines prescribed for dogs. Through this treatment, parasitemia in the second animal has been kept under control and is being monitored through molecular tests. Previously, no canine cases had been notified from urban neighborhoods in the city of Belém, but only on the island of Cotijuba, at a distance of 29 kilometers from the city. Cases of canine and human leishmaniasis have been recorded close to the capital, Belém, which has areas of conserved vegetation and where the presence of disease vectors has been described. Thus, as has been done in several other Brazilian cities, this study uses clinical and laboratory findings to confirm the presence of autochthonous cases of canine visceral leishmaniasis in the city of Belém.

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The acidity of a solution is associated with the concentration of Brønsted acids. This work proposes a new non-titrimetric potentiometric method using citrate buffer for the determination of vinegar acidity. The difference between the pH values before and after the addition of a diluted vinegar sample to 10 mmol L-1 citrate buffer (pH 5.5) was related to the acetic acid concentration. The dynamic range of the quadratic analytical curve was from 3.5 to 20 mmol L-1 (R2 = 0.998). The repeatability was 0.8% for acetic acid at 0.01 mol L-1. Comparison with the conventional titration method showed an error between 0.7% and 4.64% (n = 9) for analysis of commercial vinegar samples The behaviour of the system could be explained using the buffering function.

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Leishmaniasis is an anthropozoonosis transmitted by vectors, with dogs being the main domestic reservoirs. Brazil is one of the countries most affected by this disease, and it has been described in humans and dogs in every region in the country. In the northern region leishmaniasis cases in humans have been described in more than 100 municipalities in the State, including the capital, Belém. This study involves two cases of canine visceral leishmaniasis in which the animals developed clinical signs compatible with the disease in urban areas in Belém, the Pará state capital. The diagnosis was confirmed via polymerase chain reaction (PCR) to detect SSUr-rDNA and kDNA of Leishmania sp. and Leishmania infantum, respectively. In one of the cases the animal died and in the other the animal underwent treatment with medicines prescribed for dogs. Through this treatment, parasitemia in the second animal has been kept under control and is being monitored through molecular tests. Previously, no canine cases had been notified from urban neighborhoods in the city of Belém, but only on the island of Cotijuba, at a distance of 29 kilometers from the city. Cases of canine and human leishmaniasis have been recorded close to the capital, Belém, which has areas of conserved vegetation and where the presence of disease vectors has been described. Thus, as has been done in several other Brazilian cities, this study uses clinical and laboratory findings to confirm the presence of autochthonous cases of canine visceral leishmaniasis in the city of Belém.

A leishmaniose é uma antropozoonose transmitida por vetores, sendo os cães os principais reservatórios domésticos. O Brasil é um dos países mais acometidos por esta doença, sendo descrita em humanos e cães em todas as regiões do país. Na região norte casos de leishmaniose em humanos foram descritos em mais de 100 municípios do Estado, incluindo a capital, Belém. Este estudo envolve dois casos de leishmaniose visceral canina em que os animais desenvolveram sinais clínicos compatíveis com a doença em áreas urbanas de Belém, capital do estado do Pará. O diagnóstico foi confirmado pela reação em cadeia da polimerase (PCR) para detectar o SSUr-rDNA e kDNA de Leishmania sp e Leishmania infantum, respectivamente. Em um dos casos o animal veio a óbito e no outro o animal foi submetido a tratamento com medicamentos prescritos para cães. Por meio desse tratamento, a parasitemia no segundo animal foi mantida sob controle e está sendo monitorada por meio de testes moleculares. Anteriormente, nenhum caso canino havia sido notificado em bairros urbanos da cidade de Belém, apenas na ilha de Cotijuba, distante 29 quilômetros da cidade. Casos de leishmaniose canina e humana foram registrados próximo à capital, Belém, que possui áreas de vegetação conservada e onde foi descrita a presença de vetores de doenças. Assim, como tem sido registrado em várias outras cidades brasileiras, este estudo utiliza achados clínicos e laboratoriais para confirmar a presença de casos autóctones de leishmaniose visceral canina na cidade de Belém.

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AIM: To identify the worldwide trends in scientific evidence and gaps in knowledge regarding molar incisor hypomineralisation (MIH) and deciduous molar hypomineralisation/hypomineralised second primary molars (DMH/HSPM), exploring the contribution of authors and countries, possible etiological factors and proposed treatments, in order to guide future research in the area. METHODS: Searches were conducted in MEDLINE, Scopus, Web of Science, Cochrane Library, Lilacs/BBO, Embase and Google Scholar. Studies employing the terms MIH, DMH/HSPM and their linguistic variations were included. The following data were extracted: title, authors, year and journal of publication and first author's affiliation country. Studies were categorized according to topic, dentition, study design, etiological factors and types of treatments. Categories were analysed in relation to their distribution, co-occurrence, cross-correlation and/or autocorrelation. RESULTS: Five hundred and three studies were included. The most published authors were Manton D (n = 47), de Souza JF (n = 22) and Ghanim A (n = 22) and four main collaboration clusters have been identified. Most of the studies were conducted on permanent dentition (MIH) (87.4%); with observational design (57.2%). The "European Archives of Paediatric Dentistry" was the most published journal (13.3%) and a significant increase in the number of publications was observed in the last decade. MIH was most studied in relation to prevalence/incidence, systemic factors involved in its aetiology and treatment with composite restorations, while a gap in knowledge was observed for extraction and sealants. Less studies were published on DMH/HSPM and most of them evaluated risk factors or prevalence/incidence. The gap of knowledge was observed in relation to treatments and patient's quality of life. CONCLUSIONS: This bibliometric review provided a comprehensive overview of research in MIH and DMH/HSPM over the past 19 years. Within the limitations of the present study, the following conclusions can be drawn: global trends point to an increasing peak of scientific publication, especially in the last decade, while there is a shortage of clinical studies on treatments, mainly evaluating tooth extractions. Finally the multifactorial nature should be further explored, considering environmental and systemic factors together.

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Liposomes containing magnetic nanoparticles (magnetoliposomes) have been extensively explored for targeted drug delivery. However, the magnetic effect of nanoparticles movement is also an attractive choice for the conduction of signals in communication systems at the nanoscale level because of the simple manipulation and efficient control. Here, we propose a model for the transmission of electrical and luminous signals taking advantage of magnetophoresis. The study involved three steps. Firstly, magnetite was synthesized and incorporated into fusogenic large unilamellar vesicles (LUVs) previously associated with a fluorescent label. Secondly, the fluorescent magnetite-containing LUVs delivered their contents to the giant unilamellar vesicles (GUVs), which were corroborated by magnetophoresis and fluorescence microscopy. In the third step, magnetophoresis of magnetic vesicles was used for the conduction of the luminous signal from a capillary to an optical fibre connected to a fluorescence detector. Also, the magnetophoresis effects on subsequent transmission of the electrochemical signal were demonstrated using magnetite associated with CTAB micelles modified with ferrocene. We glimpse that these magnetic supramolecular systems can be applied in micro- and nanoscale communication systems.

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OBJECTIVE: To compare the acromegaly mortality rates with those expected for the general population from studies published before and after 2008. METHODS: We performed a systematic review and included observational studies in which the number of deaths observed in acromegaly was compared with the expected mortality for the general population mortality observed/expected (O/E). The following electronic databases were used as our data sources: EMBASE, MEDLINE and LILACS. From the observed and expected deaths, we recalculated all standardized mortality ratios (SMR) and their respective confidence intervals (95% CI), which were plotted in a meta-analysis using the software RevMan 5.3. RESULTS: We identified 2303 references, and 26 studies fulfilled our eligibility criteria. From the 17 studies published before 2008, the mortality in acromegaly was increased, while from the nine studies published after 2008, the mortality was not different from the general population (SMR: 1.35, CI: 0.99-1.85). In six studies where somatostatin analogs (SAs) were used as adjuvant treatment, acromegaly mortality was not increased (SMR: 0.98, CI: 0.83-1.15), whereas in series including only patients treated with surgery and/or radiotherapy, mortality was significantly higher (SMR: 2.11; CI: 1.54-2.91). In studies published before and after 2008, the mortality was not increased in patients who achieved biochemical control, while it was higher in those with active disease. Cancer has become a leader cause of deaths in acromegaly patients in the last decade, period in which life expectancy improved. CONCLUSION: Mortality in acromegaly is normalized with biochemical control and decreased in the last decade with the more frequent use of SAs as adjuvant therapy. Increased life expectancy has been associated with more deaths due to cancer.

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AIM: To test the hypothesis that polyacrylic acid-based and calcium silicate materials are able to increase mineral density of artificially demineralized dentine produced by a microcosm model for caries formation. METHODOLOGY: Forty-five dentine cavities were prepared in nine sound human third molars (five in each tooth). Specimens received a bacterial inoculum and were incubated in BHI plus 5% of sucrose for 96 h to allow biofilm formation. After that, the specimens were scanned in a high energy micro-CT (baseline stack) and then, each cavity was filled with different cements: zinc polycarboxylate (Poly Zinc™, Prevest DenPro, Jammu, India), conventional glass-ionomer (Ketac Molar, 3M ESPE, Seefeld, Germany) and two calcium silicate-based materials (MTA, Angelus, Londrina, Brazil and Biodentine™, Septodont, Saint Maur des Fosses, France) whilst the central cavity was filled with utility wax (negative control). Specimens were kept for 45 days under simulated intrapulpal pressure using simulated body fluid and after, they were again scanned (treated stacks). Reconstruction of the acquired projections was accomplished using standardized parameters, and the percentage mineral density change was calculated around each cavity. Data were tested for normality using the Shapiro-Wilk test, followed by nonparametric methods. RESULTS: A microcosm artificial caries model was able to cause dentine demineralization (±90% related to sound dentine). Significant increases in dentine mineral density were achieved using MTA or Poly Zinc™ (43.56% and 41.64% remineralization), followed by Biodentine™ (36.40%) and Ketac Molar (32.54%), P < 0.05. CONCLUSION: All cements increased mineral density in demineralized dentine, but zinc polycarboxylate cement and MTA had greater bioactive potential. Micro-CT proved to be an effective method to evaluate changes in mineral density within dentine in contact with bioactive materials.

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AIM: To evaluate the effects of progressive apical enlargement on the amount of unprepared root canal surface area and remaining dentine thickness. METHODOLOGY: The root canals of 30 extracted mandibular incisors with Vertucci's type I configuration were instrumented with rotary HyFlex CM instruments (Coltene-Whaledent, Altstätten, Switzerland) up to 4 instruments larger than the first one that bound at the working length (WL). Teeth were scanned in a micro-computed tomography (micro-CT) device before canal preparation and after instrumentation with the 2nd, 3rd and 4th larger instruments. The amount of unprepared surface area in the full canal or in the apical 4 mm as well as the remaining dentine thickness at 10 mm from the WL were calculated and compared. The general linear model for repeated measures adjusted by Bonferroni's post hoc test was used for statistic analysis. RESULTS: There was a significant reduction in the amount of unprepared areas after each increase in preparation size (P < 0.01). This was observed for both the full canal length and the 4-mm apical segment. The amount of remaining dentine was also significantly reduced after each file size (P < 0.01). However, dentine thickness always remained greater than 1 mm, even after using the largest instrument. CONCLUSION: Apical preparations up to 4 instruments larger than the first one to bind at the WL caused a significant progressive reduction in the unprepared canal area.

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OBJECTIVE: the aim of this study was to evaluate the marginal misfit at the interface between a ceramic coping and its abutment. METHODS: Twenty-four specimens were made with solid abutments. The specimens were divided into 3 groups according to the ceramic system (n = 8): Lava (zirconia), IPS e.max Press (lithium disilicate), and IPS Empress Esthetic (leucite). All copings were cemented with resin luting agent (RelyX U200) and the marginal misfit were evaluated at 3 different times: initial, after cementation, and after mechanical cycling using a linear measuring microscope (Measuring Microscope STM-Olympus) at a magnification of 40x. All specimens were subjected to mechanical cycling (1 million cycles) by an universal testing machine (Instron 8800). The results were statistically analyzed using Analysis of Variance and Student's t-test (α = 0.05). RESULTS: all groups showed an increase in the marginal misfit after cementation. The lithium disilicate group demonstrated the lowest interacial gap values at each evaluation (p = 0.001). The zirconia and leucite groups showed similar interfacial gap values (initial, p = 0.244; and post cementation, p = 0.751). CONCLUSIONS: the cementation increase the marginal misfit, but the mechanical cycling did not influence the marginal misfit of the ceramics systems evaluated.

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AIM: To evaluate, using a novel micro-CT approach, the solubility and dimensional changes of an MTA-based sealer inside the root canal system after a solubility challenge. The MTA-based material (MTA Fillapex) was compared to a gold standard epoxy-based endodontic sealer (AH Plus). METHODOLOGY: Ten human mandibular premolars with a single canal were divided randomly into two groups (n = 5) according to the sealer used. The canals were instrumented using the Reciproc System (VDW) with a R40 file and filled with R40 gutta-percha cones and one of the sealers. The filled canals were immediately scanned in a micro-CT, and after that, the teeth were immersed in 20 mL phosphate-buffered saline (PBS) at 37 °C for 7 days, when they were removed and rescanned. Final image stacks were registered against the initial stacks and the numerical difference between the initial and final volume of the filling material was obtained. Calculations were performed to identify dimensional changes of the filling material. All image stacks were 3D rendered to disclose areas of dislocation of the filling material inside or outside the root canal. The Shapiro-Wilk's test revealed that data were normally distributed; thus, the Student's t-test was used to detect statistically significant changes, assuming a 5% α-error. RESULTS: No significant changes were seen for the percentage volume of material lost after the solubility challenge for both AH Plus and MTA Fillapex groups (1.44% and 1.16%, respectively). A significant difference was, however, found for the volume of filling material which revealed dimensional changes after the solubility test (6.68% for MTA Fillapex and 1.09% for AH Plus). In fact, observation of 3D models disclosed that MTA Fillapex was associated with material extrusion through the foramen in all but one sample. In AH Plus filled samples, no material extrusion was detected. CONCLUSIONS: Although the solubility of both sealers was similar using this novel micro-CT approach, MTA Fillapex was associated with significant dimensional changes related to material extrusion through the apex after PBS storage compared to AH Plus.

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AIM: To evaluate the effect of depth of insertion of an irrigation needle tip on the removal of hard-tissue debris using micro-computed tomographic (micro-CT) imaging. METHODOLOGY: Twenty isthmus-containing mesial roots of mandibular molars were anatomically matched based on similar morphological dimensions using micro-CT evaluation and assigned to two groups (n = 10), according to the depth of the irrigation needle tip during biomechanical preparation: 1 or 5 mm short of the working length (WL). The preparation was performed with Reciproc R25 file (tip size 25, .08 taper) and 5.25% NaOCl as irrigant. The final rinse was 17% EDTA followed by bidistilled water. Then, specimens were scanned again, and the matched images of the canals, before and after preparation, were examined to quantify the amount of hard-tissue debris, expressed as the percentage volume of the initial root canal volume. Data were compared statistically using the Mann-Whitney U-test. RESULTS: None of the tested needle insertion depths yielded root canals completely free from hard-tissue debris. The insertion depth exerted a significant influence on debris removal, with a significant reduction in the percentage volume of hard-tissue debris when the needle was inserted 1 mm short of the WL (P < 0.05). CONCLUSIONS: The insertion depth of irrigation needles significantly influenced the removal of hard-tissue debris. A needle tip positioned 1 mm short of the WL resulted in percentage levels of hard-tissue debris removal almost three times higher than when positioned 5 mm from the WL.

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AIM: To evaluate the effect of 17% ethylenediaminetetraacetic acid (EDTA), 2.25% peracetic acid (PA) or 10% citric acid (CA) on the push-out bond strength of calcium silicate-based endodontic sealers [MTA Fillapex (Angelus, Londrina, Brazil) and Total Fill BC Sealer (FKG, La Chaux-de-Fonds, Switzerland)] to root dentine after different periods of immersion in phosphate-buffered saline (PBS). AH Plus (Dentsply DeTrey, Konstaz, Germany) was used as a reference material for comparison. METHODOLOGY: Thirty human maxillary incisors were selected and three 1-mm discs were obtained from the middle third of each root. On the axial surface of each disc, three 0.8-mm-diameter holes were drilled through the dentine. After standardized irrigation, each dentine disc from the same root was treated for smear-layer removal with one of the three tested chelating solutions: EDTA, PA or CA. After that, the holes were dried with paper points and filled with one of the three test root canal sealers. The filled dental slices were further immersed in PBS solution (pH 7.2) for 7 days (T1) or 30 days (T2) at 37 °C, before the push-out assay. Friedman, Kruskal-Wallis and Mann-Whitney tests were used respectively to estimate the impact of the independent variables (solutions, sealers and period of PBS immersion) on the push-out bond strength. The level for significance was set at α = 5% and data were further subjected to a Bonferroni correction. RESULTS: Solutions and periods of immersion did not significantly influence the displacement resistance (P = 0.285, and P = 0.104, respectively) of sealers to root dentine. On the other hand, the type of sealer significantly affected the push-out bond strength (P = 0.000). AH Plus was associated with greater resistance to dislodgment compared with Total Fill BC Sealer and MTA Fillapex (P = 0.000). MTA Fillapex resulted in the lowest push-out bond strength (P = 0.000). CONCLUSION: The use of different chelating agents did not influence the push-out bond strength of endodontic sealers. Calcium silicate-based sealers had lower push-out bond strength values compared with a conventional epoxy resin-based sealer (AH Plus).

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We analyzed 80 plants of the sugarcane (Saccharum spp) variety 'RB867515' in order to investigate its diversity and genetic structure at the molecular level. Four simple sequence repeat (SSR) loci (UGSM51, SMC1237, SEGMS1069, and UGSM38) and five expressed sequence tag (EST)-SSR loci (ESTA68, ESTB92, ESTB145, ESTC66, and ESTC84) were used as molecular markers. The polymorphic loci rate was 66.6%. A total of 17 alleles and an average of 1.88 alleles/locus were detected. The number of alleles in the EST-SSR loci was lower than the number of alleles in the SSRs of non-expressed loci. The mean observed heterozygosity among the nine SSR loci was 0.3291. Genetic structure analysis showed that 'RB867515' contains alleles from three ancestral groups (K = 3), but there is little admixing of alleles in the same plant (from 0.8 to 17.3%); only 1.88% of the plants shared alleles from two or three groups. ESTB92, ESTC84, and UGSM38 were monomorphic, but there was evidence of polymorphism in ESTA68, ESTB145, ESTC66, UGSM51, SMC1237, and SEGMS1069, indicating that 'RB867515' has variability at the molecular level and the potential to be used as a parent in breeding programs. The molecular variability observed in 'RB867515' indicates that the clone terminology that is used to identify this cultivar is inconsistent with the original meaning of "clone", which is defined as a sample of genetically identical plants.

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AIM: To evaluate the potential for electromagnetic interference (EMI) of electronic apex locators (EALs) and a gutta-percha heating device (HD) in patients with implantable cardiac pacemakers (ICPs) or cardioverter-defibrillators (ICDs). METHODOLOGY: Two types of EALs (Romiapex A-15 and Novapex) and a HD (Touch'n Heat) were tested in patients followed in an outpatient clinic for cardiac arrhythmias. The heart rhythm was monitored on a computer screen during all experimental phases. After baseline data collection, the patient held each appliance (turned on) for 30 s, simulating their clinical use. If background noise was detected on the cardiac monitor, the sensitivity of the ICP/ICD was lowered by the cardiologist to evaluate the intensity of the detected EMI. RESULTS: Twelve patients were evaluated (5 female and 7 male), and in nine instances, background noise in their cardiac devices related to the use of the endodontic devices was detected (6 patients). After lowering the sensitivity of the cardiac implants, three patients had more severe EMI in six instances, including pauses in ICP function. The presence of a symptomatic or asymptomatic pause was related to the patient's underlying heart rhythm. The HD device produced background noise more often compared to EALs. These were associated with more severe types of EMI. CONCLUSION: The EALs and gutta-percha HD were capable of causing background noise detection or pauses in cardiac implants in vivo. The use of electronic dental devices nearby patients with cardiac implants should be carefully considered in clinical practice.

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The bovine papillomavirus (BPV) causes papillomas that regress spontaneously, but can also progress to malignancy. This study evaluated the role of BPV in oncogenesis. Twenty-four samples from uninfected calves and the papillomas of BPV infected cattle were subjected to molecular diagnosis, as well as histopathological and immunohistochemical analyses. The comet assay (CA) was used to evaluate the clastogenic potential of BPV. The results confirmed the presence of BPV-2, 3, 5, and 9 in infected samples. Histopathological analysis revealed acanthosis, koilocytosis, hypergranulosis, hyperkeratosis, and transformed fibroblasts.E7 and L1 BPV proteins were detected in the epithelium, as well as in the connective tissues, indicating productive infection at different sites. CA results showed that BPV-2, 5, and 9 exhibit the same level of clastogenicity. These findings support the oncogenic action of BPV in establishing a favorable microenvironment for oncogenesis.

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PURPOSE: To compare the clinical aspects and microbial profile of children with and without early childhood caries (ECC). STUDY DESIGN: 14 patients (7 without caries and 7 with ECC) were submitted to anamnesis, clinical exam and saliva collection for microbiological analyses. Counts of Streptococcus mutans, Lactobacillus spp. Candida spp., and total microorganisms were performed by culture methods. Microbial diversity was characterized by PCR-DGGE. Demographic/clinical data and salivary microbial counts were compared between groups. RESULTS: Habits of hygiene and breastfeeding presented no association with ECC. Use of pacifiers was associated with absence of caries (p=0.035). Counts of total microorganisms and Candida spp. did not differ between the groups. The ECC group presented larger quantity of S. mutans (p=0.026) and Lactobacillus spp. (p=0.002). There was no correlation between microorganisms and breastfeeding and pacifier use. The dmf-t of ECC Group was 10.5 ± 1.9 and the modified dmf-t was 11.3 ± 3.6. The DGGE demonstrated difference in the pattern of bands between the groups. CONCLUSION: Pacifiers usage was associated with the absence of ECC and microorganism number was higher in the caries group. The PCR-DGGE revealed a characteristic microbial diversity in the ECC Group, being an excellent tool for observing the dynamics of the salivary microbial community in these patients.

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AIM: To propose an automated image processing routine based on free software to quantify root canal preparation outcomes in pairs of sound and instrumented roots after micro-CT scanning procedures. METHODOLOGY: Seven mesial roots of human mandibular molars with different canal configuration systems were studied: (i) Vertucci's type 1, (ii) Vertucci's type 2, (iii) two individual canals, (iv) Vertucci's type 6, canals (v) with and (vi) without debris, and (vii) canal with visible pulp calcification. All teeth were instrumented with the BioRaCe system and scanned in a Skyscan 1173 micro-CT before and after canal preparation. After reconstruction, the instrumented stack of images (IS) was registered against the preoperative sound stack of images (SS). Image processing included contrast equalization and noise filtering. Sound canal volumes were obtained by a minimum threshold. For the IS, a fixed conservative threshold was chosen as the best compromise between instrumented canal and dentine whilst avoiding debris, resulting in instrumented canal plus empty spaces. Arithmetic and logical operations between sound and instrumented stacks were used to identify debris. Noninstrumented dentine was calculated using a minimum threshold in the IS and subtracting from the SS and total debris. Removed dentine volume was obtained by subtracting SS from IS. RESULTS: Quantitative data on total debris present in the root canal space after instrumentation, noninstrumented areas and removed dentine volume were obtained for each test case, as well as three-dimensional volume renderings. CONCLUSION: After standardization of acquisition, reconstruction and image processing micro-CT images, a quantitative approach for calculation of root canal biomechanical outcomes was achieved using free software.

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