Scielo RSS <![CDATA[Journal of Applied Oral Science]]> http://www.scielo.br/rss.php?pid=1678-775720160005&lang=en vol. 24 num. 5 lang. en <![CDATA[SciELO Logo]]> http://www.scielo.br/img/en/fbpelogp.gif http://www.scielo.br <![CDATA[Sustained drug-delivery system: a promising therapy for denture stomatitis?]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1678-77572016000500420&lng=en&nrm=iso&tlng=en <![CDATA[The effect of <em>hippophae rhamnoides</em> extract on oral mucositis induced in rats with methotrexate]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1678-77572016000500423&lng=en&nrm=iso&tlng=en ABSTRACT Objective: To investigate the effect of HRE (Hippophae rhamnoides extract) on oral mucositis induced in rats with MTX. Material and Methods: Experimental animals were divided into groups as healthy (HG), HRE+MTX (HMTX), and control group, which received MTX (MTXC). HMTX group received 50 mg/kg HRE while MTXC and HG groups received equivolume distilled water with gavage once a day. After one hour of HRE and distilled water administration, HMTX and MTXC groups received a single dose of oral MTX 5 mg/ kg. This procedure was repeated for one month. Results: The levels of MDA, IL-1β, and TNF-α were found to be significantly higher in the cheek, lower lip, and tongue tissue of the animals receiving MTX, compared with HG and HMTX groups; however, these parameters were lower in the cheek and low lip tissue, and a milder damage ocurred in these tissues, compared with the tongue tissue in MTXC group. No histopathologic damage was observed in the cheek, lower lip, and tongue tissues of the rats treated with HRE. Conclusion: This findings indicate that HRE as a natural product is an important advantage compared with synthetic drugs for prophylaxis of oral mucositis developed due to MTX. <![CDATA[Factors influencing orthodontic treatment time for non-surgical Class III malocclusion]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1678-77572016000500431&lng=en&nrm=iso&tlng=en ABSTRACT To improve orthodontic treatment efficiency, orthodontists must know which variables could interfere with orthodontic treatment time. Objective: To identify variables and their effect size on orthodontic treatment time of Class III malocclusion. Material and Methods: Forty-five Class III malocclusion cases were selected from 2008 patients’ records. Clinical charts, cephalometric radiographs, and pre and posttreatment dental casts were evaluated. Age, sex, PAR index at T1 and T2, overjet, missing teeth, extractions, number of treatment phases, missed appointments, appliance breakages, and cephalometric variables SNA, SNB, ANB, Wits, SnGoGn, CoA, CoGn, IMPA, 1.PP were investigated by multiple linear regression analysis and stepwise method at p&lt;0.05. The sample was also divided into two groups: Group 0-2 (patients who had missed two clinical appointments or less) and Group &gt;2 (patients who missed more than 2 appointments), to detect the influence of this data on treatment time and the quality of the treatment (PAR T2). Results: Average treatment time was 30.27 months. Multiple regression analysis showed that missed appointment (R2=0.4345) and appliance breakages (R2=0.0596) are the only variables able to significantly predict treatment duration. Treatment time for patients who missed more than 2 appointments was nearly one year longer. However, no significant influence on PAR T2 was observed for those patients. Conclusion: Orthodontic treatment duration in Class III patients is mainly influenced by factors related to patient compliance. Patients who missed more appointments did not show worse orthodontic finishing, but longer treatment. No occlusal, cephalometric, or demographic variable obtained before treatment was able to give some significant prediction about treatment time in Class III patients. <![CDATA[Effects of the application techniques of self-adhesive resin cements on the interfacial integrity and bond strength of fiber posts to dentin]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1678-77572016000500437&lng=en&nrm=iso&tlng=en ABSTRACT Objective: To evaluate the influence of an application technique of a glass-fiber post using self-adhesive resin cements on the push-out bond strength and the presence of bubbles in the root thirds. The cements were either applied according to the manufacturer's instruction or using a commercial delivering system (Centrix), at which the cement pastes were collected and applied after manipulation. Material and Methods: Self-adhesive resin cements (RelyX U200/3M ESPE-U200; Maxcem Elite/Kerr-MAX; Clearfil SA Cement/Kuraray-CSA) and a conventional cement (RelyX ARC/3M ESPE-ARC) were used to cement a post and applied either based on the manufacturer's instructions or using a Centrix syringe to deliver the cements directly onto the post of choice, or directly into canal. The roots were scanned with a micro-computed tomography (μCT) and then sectioned into nine 1-mm thick slices for a push-out bond strength test. The μCT images showed the percentage of bubbles in the root thirds (cervical, medium, and apical). Data were analyzed with three-way ANOVA/Tukey (α=0.05). Results: Triple interaction was not significant (p&gt;0.05). The interaction “material” vs “root third” was not significant. A significant interaction was observed between “material” vs “application technique” (p&lt;0.05). For ARC, U200, and MAX, significantly lower percentages of bubbles were observed when the Centrix syringe delivered the cements. Equivalent percentages of voids were observed for CSA, irrespective of the application technique (p&gt;0.05). Significantly higher bond strength was observed when the self-adhesive resin cements were applied using the Centrix delivery system, in comparison with the manufacturer's instructions (p&lt;0.05). Bond strength varied with the root third: cervical&gt;medium&gt;apical (p&lt;0.05). No correlations were found between the bond strength and voids. Conclusions: Bond strength and voids are negatively influenced by the conventional application technique for luting fiber posts. The delivery system (Centrix) seems to produce better results when cementing fiber posts. <![CDATA[Reliability, failure probability, and strength of resin-based materials for CAD/CAM restorations]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1678-77572016000500447&lng=en&nrm=iso&tlng=en ABSTRACT Objective: This study investigated the Weibull parameters and 5% fracture probability of direct, indirect composites, and CAD/CAM composites. Material and Methods: Discshaped (12 mm diameter x 1 mm thick) specimens were prepared for a direct composite [Z100 (ZO), 3M-ESPE], an indirect laboratory composite [Ceramage (CM), Shofu], and two CAD/CAM composites [Lava Ultimate (LU), 3M ESPE; Vita Enamic (VE), Vita Zahnfabrik] restorations (n=30 for each group). The specimens were polished, stored in distilled water for 24 hours at 37°C. Weibull parameters (m= modulus of Weibull, σ0= characteristic strength) and flexural strength for 5% fracture probability (σ5%) were determined using a piston-on-three-balls device at 1 MPa/s in distilled water. Statistical analysis for biaxial flexural strength analysis were performed either by both one-way ANOVA and Tukey's post hoc (α=0.05) or by Pearson's correlation test. Results: Ranking of m was: VE (19.5), LU (14.5), CM (11.7), and ZO (9.6). Ranking of σ0 (MPa) was: LU (218.1), ZO (210.4), CM (209.0), and VE (126.5). σ5% (MPa) was 177.9 for LU, 163.2 for CM, 154.7 for Z0, and 108.7 for VE. There was no significant difference in the m for ZO, CM, and LU. VE presented the highest m value and significantly higher than ZO. For σ0 and σ5%, ZO, CM, and LU were similar but higher than VE. Conclusion: The strength characteristics of CAD/ CAM composites vary according to their composition and microstructure. VE presented the lowest strength and highest Weibull modulus among the materials. <![CDATA[Porosity of temporary denture soft liners containing antifungal agents]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1678-77572016000500453&lng=en&nrm=iso&tlng=en ABSTRACT Incorporation of antifungals in temporary denture soft liners has been recommended for denture stomatitis treatment; however, it may affect their properties. Objective: To evaluate the porosity of a tissue conditioner (Softone) and a temporary resilient liner (Trusoft) modified by minimum inhibitory concentrations (MICs) of antifungal agents for Candida albicans biofilm. Material and Methods: The porosity was measured by water absorption, based on exclusion of the plasticizer effect. Initially, it was determined by sorption isotherms that the adequate storage solution for specimens (65×10×3.3 mm) of both materials was 50% anhydrous calcium chloride (S50). Then, the porosity factor (PF) was calculated for the study groups (n=10) formed by specimens without (control) or with drug incorporation at MICs (nystatin: Ny-0.032 g, chlorhexidine diacetate: Chx-0.064 g, or ketoconazole: Ke-0.128 g each per gram of soft liner powder) after storage in distilled water or S50 for 24 h, seven and 14 d. Data were statistically analyzed by 4-way repeated measures ANOVA and Tukey's test (α=.05). Results: Ke resulted in no significant changes in PF for both liners in water over 14 days (p&gt;0.05). Compared with the controls, Softone and Trusoft PFs were increased at 14-day water immersion only after addition of Ny and Chx, and Chx, respectively (p&lt;0.05). Both materials showed no significant changes in PF in up to 14 days of S50 immersion, compared with the controls (p&gt;0.05). In all experimental conditions, Softone and Trusoft PFs were significantly lower when immersed in S50 compared with distilled water (p&lt;0.05). Conclusions: The addition of antifungals at MICs resulted in no harmful effects for the porosity of both temporary soft liners in different periods of water immersion, except for Chx and Ny in Softone and Chx in Trusoft at 14 days. No deleterious effect was observed for the porosity of both soft liners modified by the drugs at MICs over 14 days of S50 immersion. <![CDATA[Occurrence and antimicrobial susceptibility of enteric rods and pseudomonads isolated from the dental prostheses biofilm]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1678-77572016000500462&lng=en&nrm=iso&tlng=en ABSTRACT Aspiration of oral bacteria leads to cardiac and respiratory infectious diseases and dentures can act as a reservoir for pathogenic microorganisms. Objective: To determine the occurrence and the in vitro antimicrobial susceptibility of enteric rods and pseudomonads from the denture biofilm of 52 subjects at the Center for Dental Specialties of Sobral/ Ceara, Brazil. Material and Methods: Denture biofilm was collected and samples plated on MacConkey agar. The isolated bacterial colonies were identified using the BBL Crystal enteric/non-fermenter system. Antibiotic bacterial susceptibility was assessed by the disc diffusion method of amoxicillin, amoxicillin/clavulanic acid, doxycycline, tetracycline, tobramycin, imipenem, cefotaxime, and ciprofloxacin. The Minimum Inhibitory Concentration (MIC) of cefotaxime, tobramycin, doxycycline, imipenem, and ciprofloxacin was determined for 40 species by E-test. Results: 34 subjects (65.4%) harbored enteric rods in their prostheses. Klebsiella pneumoniae (26.5%), Escherichia coli (23.5%), and Enterobacter aerogenes (23.5%) were the most prevalent species. All organisms were susceptible to ciprofloxacin and most species were resistant to amoxicillin or amoxicillin/clavulanic acid, demonstrating variable sensitivity patterns to other antimicrobials. However, the MIC showed the emergence of strains with reduced sensitivity to ciprofloxacin (MIC90≥3 μg/ mL) and cefotaxime (MIC90≥2 μg/mL). Conclusion: The findings show high prevalence of nosocomial diseases-related bacterial species and low susceptibility to antimicrobial drugs. Therefore, these results imply caution against the indiscriminate use of broad spectrum antibiotics in dental practice. <![CDATA[Analysis of speech and tongue motion in normal and post-glossectomy speaker using cine MRI]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1678-77572016000500472&lng=en&nrm=iso&tlng=en ABSTRACT Objective Since the tongue is the oral structure responsible for mastication, pronunciation, and swallowing functions, patients who undergo glossectomy can be affected in various aspects of these functions. The vowel /i/ uses the tongue shape, whereas /u/ uses tongue and lip shapes. The purpose of this study is to investigate the morphological changes of the tongue and the adaptation of pronunciation using cine MRI for speech of patients who undergo glossectomy. Material and Methods Twenty-three controls (11 males and 12 females) and 13 patients (eight males and five females) volunteered to participate in the experiment. The patients underwent glossectomy surgery for T1 or T2 lateral lingual tumors. The speech tasks “a souk” and “a geese” were spoken by all subjects providing data for the vowels /u/ and /i/. Cine MRI and speech acoustics were recorded and measured to compare the changes in the tongue with vowel acoustics after surgery. 2D measurements were made of the interlip distance, tongue-palate distance, tongue position (anterior-posterior and superior-inferior), tongue height on the left and right sides, and pharynx size. Vowel formants Fl, F2, and F3 were measured. Results The patients had significantly lower F2/Fl ratios (F=5.911, p=0.018), and lower F3/F1 ratios that approached significance. This was seen primarily in the /u/ data. Patients had flatter tongue shapes than controls with a greater effect seen in /u/ than /i/. Conclusion The patients showed complex adaptation motion in order to preserve the acoustic integrity of the vowels, and the tongue modified cavity size relationships to maintain the value of the formant frequencies. <![CDATA[Interaction of dental pulp stem cells with Biodentine and MTA after exposure to different environments]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1678-77572016000500481&lng=en&nrm=iso&tlng=en ABSTRACT Objective: The aim of the present study was to evaluate and compare the cytotoxic effects of Biodentine and MTA on dental pulp stem cells (DPSCs) and to assess cell viability and adherence after material exposure to an acidic environment. Material and Methods: DPSCs were cultured either alone or in contact with either: Biodentine; MTA set for 1 hour; or MTA set for 24 hours. After 4 and 7 days, cell viability was measured using the MTT assay. Biodentine and MTA were also prepared and packed into standardized bovine dentin disks and divided into three groups according to the storage media (n=6/group): freshly mixed materials without storage medium (Group A); materials stored in saline (Group B); materials stored in citric acid buffered at pH 5.4 (Group C). After 24 hours, DPSCs were introduced in the wells and cell adherence, viability, and cellular morphology were observed via confocal microscopy after three days of culture. Cell viability was analyzed using repeated-measures analysis of variance test with Tukey's post hoc tests (α=0.05). Results: Biodentine expressed significantly higher cell viability compared with all other groups after 4 days, with no differences after 7 days. Notably, cell viability was significantly greater in 24-hour set MTA compared with 1-hour set MTA and control groups after 7 days. Material exposure to an acidic environment showed an increase in cell adherence and viability in both groups. Conclusions: Biodentine induced a significantly accelerated cell proliferation compared with MTA. Setting of these materials in the presence of citric acid enhanced DPSC viability and adherence. <![CDATA[Exopolysaccharide dispelled by calcium hydroxide with volatile vehicles related to bactericidal effect for root canal medication]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1678-77572016000500487&lng=en&nrm=iso&tlng=en ABSTRACT Objective: Enterococcus faecalis is the dominant microbial species responsible for persistent apical periodontitis with ability to deeply penetrate into the dentin. Exopolysaccharides (EPS) contribute to the pathogenicity and antibiotic resistance of E. faecalis. Our aim was to investigate the antimicrobial activity of calcium hydroxide (CH), camphorated parachlorophenol (CMCP), and chlorhexidine (CHX) against E. faecalis in dentinal tubules. Material and Methods: Decoronated single-canal human teeth and semicylindrical dentin blocks were incubated with E. faecalis for 3 weeks. Samples were randomly assigned to six medication groups for 1 week (n=10 per group): CH + 40% glycerin-water solution (1:1, wt/vol); CMCP; 2% CHX; CH + CMCP (1:1, wt/vol); CH + CMCP (2:3, wt/vol); and saline. Bacterial samples were collected and assayed for colony-forming units. After dentin blocks were split longitudinally, confocal laser scanning microscopy was used to assess the proportion of viable bacteria and EPS production in dentin. Results: CMCP exhibited the best antimicrobial activity, while CH was the least sensitive against E. faecalis (p&lt;0.05). CHX showed similar antimicrobial properties to CH + CMCP (1:1, wt/vol) (p&gt;0.05). CH combined with CMCP inhibited EPS synthesis by E. faecalis, which sensitized biofilms to antibacterial substances. Moreover, increasing concentrations of CMCP decreased EPS matrix formation, which effectively sensitized biofilms to disinfection agents. Conclusion: The EPS matrix dispelled by CH paste with CMCP may be related to its bactericidal effect; the visualization and analysis of EPS formation and microbial colonization in dentin may be a useful approach to verify medicaments for antimicrobial therapy. <![CDATA[Evaluation of the force generated by gradual deflection of orthodontic wires in conventional metallic, esthetic, and self-ligating brackets]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1678-77572016000500496&lng=en&nrm=iso&tlng=en ABSTRACT Objective: The purpose of this study was to evaluate the deflection forces of Nitinol orthodontic wires placed in different types of brackets: metallic, reinforced polycarbonate with metallic slots, sapphire, passive and active self-ligating, by assessing strength values variation according to gradual increase in wire diameter and deflection and comparing different combinations in the different deflections. Material and Methods: Specimens were set in a clinical simulation model and evaluated in a Universal Testing Machine (INSTRON 3342), using the ISO 15841 protocol. Data were subjected to One-way ANOVA, followed by Tukey tests (p&lt;0.05). Results: Self-ligating brackets presented the most similar behavior to each other. For conventional brackets there was no consistent behavior for any of the deflections studied. Conclusions: Self-ligating brackets presented the most consistent and predictable results while conventional brackets, as esthetic brackets, showed very different patterns of forces. Self-ligating brackets showed higher strength in all deflections when compared with the others, in 0.020-inch wires. <![CDATA[The effect of various kinematics on postoperative pain after instrumentation: a prospective, randomized clinical study]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1678-77572016000500503&lng=en&nrm=iso&tlng=en ABSTRACT Objective: To evaluate various kinematic movements on postoperative pain using a Reciproc system. Material and Methods: Fifty-six molar teeth were divided into four groups according to kinematics as follows: continuous rotation, 360° CCW – 30° CW, 270° CCW – 30° CW, and 150° CCW – 30° CW. Preoperative and postoperative pain levels using visual analogue scale (VAS), percussion pain, and analgesic intake were recorded for each subject. Postoperative pain levels at 1, 3, 5, and 7 d were evaluated. Data were analyzed statistically using the Kruskal-Walis, Mann-Whitney-U, one-way analysis of variance, and chi-square tests (p=0.05). Results: Continuous rotation resulted in more pain at Day 1 when compared with the reciprocating groups (360° CCW – 30° CW and 270° CCW – 30° C) (p&lt;0.05). Conclusions: Continuous rotation resulted in more postoperative pain at Day 1 than in reciprocating groups, and thereafter no significant pain was found among the groups. <![CDATA[Inflammatory response of human dental pulp to at-home and in-office tooth bleaching]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1678-77572016000500509&lng=en&nrm=iso&tlng=en ABSTRACT Tooth bleaching is a technique of choice to obtain a harmonious smile, but bleaching agents may damage the dental pulp. Objective: This study evaluated the inflammatory responses of human dental pulp after the use of two bleaching techniques. Material and Methods: Pulp samples were collected from human third molars extracted for orthodontic reasons and divided into three groups: control - no tooth bleaching (CG) (n=7); at-home bleaching with 15% carbamide peroxide (AH) (n = 10), and in-office bleaching with 38% hydrogen peroxide (IO) (n=12). Pulps were removed and stained with hematoxylin-eosin for microscopic analysis of inflammation intensity, collagen degradation, and pulp tissue organization. Immunohistochemistry was used to detect mast cells (tryptase+), blood vessels (CD31+), and macrophages (CD68+). Chi-square, Kruskal-Wallis, and Mann Whitney tests were used for statistical analysis. The level of significance was set at p&lt;.05. Results: The inflammation intensity and the number of macrophages were significantly greater in IO than in AH and CG (p&lt;0.05). The results of CD31+ (blood vessels per mm2) were similar in CG (61.39±20.03), AH (52.29±27.62), and IO (57.43±8.69) groups (p&gt;0.05). No mast cells were found in the pulp samples analyzed. Conclusion: In-office bleaching with 38% hydrogen peroxide resulted in more intense inflammation, higher macrophages migration, and greater pulp damage then at-home bleaching with 15% carbamide peroxide, however, these bleaching techniques did not induce migration of mast cells and increased the number of blood vessels. <![CDATA[Fragile X syndrome: panoramic radiographic evaluation of dental anomalies, dental mineralization stage, and mandibular angle]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1678-77572016000500518&lng=en&nrm=iso&tlng=en ABSTRACT Fragile X syndrome (FXS) is a disorder linked to the chromosome X long arm (Xq27.3), which is identified by a constriction named fragile site. It determines various changes, such as behavioral or emotional problems, learning difficulties, and intellectual disabilities. Craniofacial abnormalities such as elongated and narrow face, prominent forehead, broad nose, large and prominent ear pavilions, strabismus, and myopia are frequent characteristics. Regarding the oral aspects, deep and high-arched palate, mandibular prognathism, and malocclusion are also observed. Objective: The purpose of this study was to evaluate the dental radiographic characteristics as described in 40 records of patients with panoramic radiography. Material and Methods: The patients were in the range of 6–17 years old, and were divided into two groups (20 subjects who were compatible with the normality standard and 20 individuals diagnosed with the FXS), which were matched for gender and age. Analysis of the panoramic radiographic examination involved the evaluation of dental mineralization stage, mandibular angle size, and presence of dental anomalies in both deciduous and permanent dentitions. Results: The results of radiographic evaluation demonstrated that the chronology of tooth eruption of all third and second lower molars is anticipated in individuals with FXS (p&lt;0.05). In this group, supernumerary deciduous teeth (2.83%), giroversion of permanent teeth (2.31%), and partial anodontia (1.82%) were the most frequent dental anomalies. In addition, an increase was observed in the mandibular angle size in the FXS group (p&lt;0.05). Conclusion: We conclude that knowledge of dental radiographic changes is of great importance for dental surgeons to plan the treatment of these individuals. <![CDATA[Prevalence, severity, and risk indicators of gingival inflammation in a multi-center study on South American adults: a cross sectional study]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1678-77572016000500524&lng=en&nrm=iso&tlng=en ABSTRACT Objectives: The aim of this study is to investigate the prevalence and severity of gingival inflammation and associated risk indicators in South American adults. Material and Methods: Multi-stage samples totaling 1,650 adults from Porto Alegre (Brazil), Tucumán (Argentina), and Santiago (Chile) were assessed. The sampling procedure consisted of a 4-stage process. Examinations were performed in mobile dental units by calibrated examiners. A multivariable logistic regression model was utilized for associating variables as indicators of gingival inflammation (GI) (Gingival Index ≥0.5). Statistical significance was set at 0.05. Results: A total of 96.5% of the adults have GI. Regarding the severity of GI, 22.5% of participants examined have mild GI, 74.0% have moderate GI, and 3.6% have severe GI. The multivariate analyses identify the main risk indicators for GI as adults with higher mean of Calculus Index (OR=18.59); with a Visible Plaque Index ≥30% (OR=14.56); living in Santiago (OR=7.17); having ≤12 years of schooling (OR=2.18), and females (OR=1.93). Conclusions: This study shows a high prevalence and severity of gingival inflammation, being the first one performed in adult populations in three cities of South America. <![CDATA[Prevalence and morphometric analysis of three-rooted mandibular first molars in a Brazilian subpopulation]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1678-77572016000500535&lng=en&nrm=iso&tlng=en ABSTRACT The knowledge of the internal anatomy of three-rooted mandibular molars may help clinicians to diagnose and plan the root canal treatment in order to provide adequate therapy when this variation is present. Objectives: To determine the prevalence of three-rooted mandibular molars in a Brazilian population using cone beam computed tomography (CBCT) and to analyze the anatomy of mandibular first molars with three roots through micro-CT. Material and Methods: CBCT images of 116 patients were reviewed to determine the prevalence of three-rooted first mandibular molars in a Brazilian subpopulation. Furthermore, with the use of micro-CT, 55 extracted three-rooted mandibular first molars were scanned and reconstructed to assess root length, distance between canal orifices, apical diameter, Vertucci's classification, presence of apical delta, number of foramina and furcations, lateral and accessory canals. The distance between the orifice on the pulp chamber floor and the beginning of the curvature and the angle of canal curvature were analyzed in the distolingual root. Data were compared using the Kruskal-Wallis test (α=0.05). Results: The prevalence of three-rooted mandibular first molars was of 2.58%. Mesial roots showed complex distribution of the root canal system in comparison to the distal roots. The median of major diameters of mesiobuccal, mesiolingual and single mesial canals were: 0.34, 0.41 and 0.60 mm, respectively. The higher values of major diameters were found in the distobuccal canals (0.56 mm) and the lower diameters in the distolingual canals (0.29 mm). The lowest orifice distance was found between the mesial canals (MB-ML) and the highest distance between the distal root canals (DB-DL). Almost all distal roots had one root canal and one apical foramen with few accessory canals. Conclusions: Distolingual root generally has short length, severe curvature and a single root canal with low apical diameter.