Abstract in English:Aim: The aim of this in vitro study was to investigate the synergistic effect of chemical degradation (erosion) and three-body abrasion (mechanical degradation) on the surface roughness (Ra) and hardness (KHN) of two nanorestorative materials and two conventional materials. Methods: Disc-shaped specimens (5 mm in diameter, 2 mm thick) of Filtek Z350TM and TPH SpectrumTM composites and Ketac NanoTM and VitremerTM light-curing glass ionomer cements, nanomaterials and conventional materials were prepared according to the manufacturer's instructions. After 24 h, polishing procedures were performed and initial measurements of Ra and KHN were taken in all specimens. The specimens were divided into 12 groups (n = 10) according to material and storage media: artificial saliva, orange juice, and Coca-Cola(r). After 30 days of storage, the specimens were submitted to mechanical degradation and re-evaluated for Ra and KHN. Data were tested for significant differences by repeated-measure three-way ANOVA and Tukey's tests (p<0.05). Results: Erosion and abrasion wear significantly decreased hardness of all materials. Only Filtek Z350 roughness, however, was not affected by erosion and abrasion. All materials showed a significant increase in surface roughness after erosion and abrasion, except for Filtek Z350. After chemical and mechanical degradation, the KHN of all samples had decreased significantly. After mechanical degradation, the acidic drinks (Coca-Cola(r) and orange juice) were more aggressive than artificial saliva to all materials. Conclusions: A synergistic effect was observed by the increase in roughness for all materials, except for Filtek Z350; hardness values decrease for all materials, regardless of whether they were nanofilled or not. The RMGICs were more susceptible to degradation than the composites, considering both hardness and roughness surface parameters.
Abstract in English:Aim: To evaluate the involvement of Th2 cells in different periods of the active phase of experimental periodontal disease and expression of the R1 subunit of the receptor for IFN-γ during the early and advanced progression of the disease. Methods: Experimental periodontitis was induced in 30 male Wistar rats by placing cotton ligatures around the mandibular first molars. The rats were then randomly assigned into two groups: G1=15 and G2=15, in group G1, ligatures were maintained for 2 days, a period that corresponds to the initial stage of periodontal disease in rats, in G2 ligatures were left for 15 days, a period that corresponds to the advanced stage of periodontal disease. The contra-lateral teeth served as controls (unligated). An immunohistochemical investigation of the gingival tissue was performed to detect the presence of the Th2 specific transcription factor (GATA3). Results: Light microscopy analysis revealed a decreased expression of GATA-3-positive cells when bone loss progressed. IFN-γ R1 was detected at an early stage during the active phase of disease, but the expression of positive cells remained unaltered during the remaining period of the study. Conclusions: These results indicate that the Th2 response may have a protective role during the pathogenesis of experimental periodontal disease, and that the IFN-γ R1 subunit may not be associated with periodontal disease progression.
Abstract in English:Aim: To evaluate the increase of pharyngeal airway space (PAS) in patients undergoing mandibular advancement. Methods: A retrospective cross-sectional study was performed in thirteen patients who underwent mandibular advancement and were evaluated by cephalometric tracing in pre and postoperative lateral radiographs. In cephalometric tracing, the PAS was assessed by measuring the distance from the lower portion of the soft palate to the posterior pharyngeal wall (UP-PHW) and from the tongue base to the posterior pharyngeal wall (TB-PHW). Results: Patients' age ranged from 22 to 42 years with an average of 28.54 ± 2.23 years. A preoperative mean of 9.20 ± 4.56 mm in the UP-PHW measure and 10.53 ± 5.84 mm in the TB-PHW measure were obtained. The mean values found for those measurements in the postoperative period were 11.61 mm and 13.95 mm, respectively. There was an average increase of 2.4 mm in the UP-PHW and of 2.95 mm in the TB-PHW. The mean mandibular advancement in evaluated patients was 5 mm. There was no statistical correlation between PAS increase and the amount of mandibular advancement for UP-PHW (p=0.058) and TB-PHW (p=0.53), as there was no such correlation either between PAS increase and the age of patients for UP-PHW (p=0.16) and TB-PHW (p=0.26). A greater effect of the retrolingual dimension in mandibular advancement was observed, with an average increase of 24.52% while in the retropalatal dimension an average increase of 20.75% was obtained. Conclusions: Surgical advancement of the mandible increases the size of the pharyngeal airway space.
Abstract in English:A previous Nigerian study had reported high incidence of periodontal disease in young Nigerians though global studies show the contrary. Aim: To determine the periodontal status and treatment needs of adolescents attending private and public secondary schools in Ibadan, south-western Nigeria. Methods: One thousand, five hundred and twenty two secondary school children in Ibadan were assessed. Sociodemographic data was obtained using a data extraction form. Intraoral examination was performed on all participants. Oral cleanliness was assessed using the plaque index of Silness and Loe, while periodontal health status and treatment needs were assessed using the Community Periodontal Index of Treatment Needs (CPITN). Data were analyzed with the Statistical Package for Social Sciences (SPSS) version 22. Statistical significance was set at p<0.05. Results: Only eight participants (0.5%) had healthy component of periodontal status. The mean plaque index was 1.12±0.41. The CPITN scores varied significantly with the gender of participants (p<0.001). Number of sextants affected by periodontal diseases varied significantly with the socioeconomic status (p=0.02). Conclusions: Gingival ill-health is prevalent among adolescent Nigerians with a great need for oral hygiene instructions and professional cleaning. There is need for oral health education among this sub-population of Nigerian children and provision of mobile dental clinics to help meet their treatment needs.
Abstract in English:Aim: To assess the effect of different torque values on cyclic fatigue resistance of K3 rotary nickel-titanium (NiTi) files. Methods: Eighty K3 files, size 25 mm, taper 0.04 were divided in 4 groups according to different torques (0.5, 1, 2 and 6 Ncm) and were submitted to a cyclic fatigue test. This test was performed with a device that allowed the file to rotate inside a stainless steel artificial curved canal, simulating the pecking motion. Files rotated until fracture occurred and time to failure was recorded in seconds with a stopwatch. Data were analyzed by ANOVA and Tukey tests (p<0.05). Results: All groups were compared and only the group of 6 N.cm showed statistically significant difference (p=0.0002). Conclusions: For #25.04 K3 files, the evaluated torques up to 2 N.cm had no influence on cyclic fatigue resistance. Using 6 N.cm torque value resulted in lower resistance to cyclic fatigue.
Abstract in English:Aim: To analyze the influence of exposure and time of exposure to phosphate buffered saline (PBS) on the push-out bond strength (BS) of Biodentine to dentine. Methods: Eighty 2-mm-thick dentin discs were obtained from transversal sections of human teeth roots. The space of the canal was enlarged using #2-#5 Gates-Glidden burs to obtain 1.3-mm-diameter standardized cavities. The discs were immersed in 17% EDTA followed by 1% NaOCl and dried. The spaces of the canals were filled with Biodentine and the samples were divided into 2 groups (n=40) according to the storage: G1: exposure to moistened cotton pellet; G2: exposure to PBS. After 30 min, 1, 3 and 28 days, 10 samples of each group were subjected to the push-out test. Data were analyzed using ANOVA and Tukey test (p < 0.05). Results: The specimens exposed to PBS had lower BS (p < 0.05), except for the 1-day period (p = 0.6017). In specimens of Group 1 the BS increased up to 3 days (p < 0.05). In specimens in Group 2, the BS increased from 30 min to 1 day (p < 0.0001) and remained stable up to 3 days (p = 0.9876). At 28 days, a significant decrease was observed in the BS values of both groups (p < 0.05). Conclusions: The exposure of Biodentine to PBS led to lower BS values. In general, the BS increased gradually up to 3 days and reduced at 28 days.
Abstract in English:Aim: To evaluate the correlation between the maxillary molar rotation center and the direction of the maximum tooth movement according to the force direction using three-dimensional finite element analysis (3D-FEA). Methods: Computed tomography of a human tooth was used to build a finite element model, which comprised the cancellous and cortical bones, the periodontal ligament and the tooth. After applying lateral and posterior boundary conditions, a 1 N force was applied to the mesial and lingual faces of the maxillary molar to simulate buccal and distal tipping forces on the tooth. Results: The initial displacement of the maxillary first molar was greater for distal tipping than for buccal tipping. The rotation axis for distal tipping in this simulation was located on the furcation of the first molar. For buccal tipping this axis was on the cervical and middle third of the buccal roots of the maxillary first molar. Conclusions: The applied movement interferes in molars Cres location. Higher molar tipping is expected when distal movement is applied rather than buccal movement thanks to the close distance between Cres and location of the force applied to this movement.
Abstract in English:Aim: To detect the expression of molecules associated with Notch signaling pathway in stem cells from human exfoliated deciduous teeth (SHED) cultured in specific differentiation medium, namely, keratinocyte growth medium (KGM). Methods: RNA was extracted from SHED harvested on day 1, 3 and 7. RNA was reverse-transcribed to obtain the cDNA and then proceeded with PCR using specific primers for the Notch signaling pathway molecules (Notch1, Jagged-1, Jagged-2 and, Hes1) as well as stem cell marker (Nanog). PCR products were electrophoresed on a 2% agarose gel and stained with SYBR green. Results: Notch-1 was highly expressed in SHED cultured in KGM and showed increase in density as the days progressed, while Jagged-1 showed a decrease. Jagged-2 on the other hand, showed a slight increase on day 3 followed by a decrease on day 7. However, Hes-1 was not expressed in SHED cultured in KGM. Nanog showed expression only on day 3 and gradually increased in expression on day 7. Conclusions: Notch signaling pathway associated molecules; Notch-1, Jagged-1, Jagged-2, and stem cell marker Nanog are expressed in SHED cultured in KGM which may be involved in the differentiation into epithelial-like cells in human dental pulp tissues.
Abstract in English:Aim: To compare the qualitative and quantitative information yielded by imaging modalities on the evaluation of the relationship between the maxillary sinus and the apices of posterior teeth. Methods: Three oral radiologists examined 109 panoramic radiographs and cone-beam computed tomography (CBCT) images obtained from a digital archive. A total of 1,875 apices were classified according to their topographic relationship in both imaging modalities. Agreements between the two imaging techniques were examined statistically. The evaluation was repeated in 25% of the sample to statistically evaluate the intraobserver agreement, with a 30-day interval. Results: The values found in the Kappa test for qualitative assessment and the intraclass correlation coefficient (ICC) for quantitative assessment showed nearly perfect and excellent correlation, respectively. Regarding the correlation between the two images, the Kappa test in the quality assessment showed a slight correlation between the palatal roots of the right first molars and second molars. Moreover, the quantitative evaluation by ICC showed poor agreement for the palatal roots of the left first molar and second molar, as well as for the buccomesial of the right second molars and for the buccodistal of the left second molars. Conclusions: There is low correlation between panoramic radiography and CBCT when roots are in contact or above the maxillary sinus floor. A high level of agreement was observed when roots are below the maxillary sinus floor.
Abstract in English:Aim: To measure the agreement of methods for identification of Candida species in oral cavity samples, comparing the CHROMagar Candida, microculture, API 20C AUX and RAPD techniques. Methods: Ninety-one colonies of Candida were isolated and presumptively identified in CHROMagar Candida, submitted to microculture, API 20C AUX and RAPD techniques. After this, agreement among methods using Kappa test was performed. Results: Agreement rates between RAPD and CHROMagar Candida, showed significant accuracy for C. albicans, C. tropicalis, C. dubliniensis and C. krusei (Kappa: 0.760, 0.640, 0.416 and 0.360, respectively, p<0.05). Comparing RAPD results with microculture, the highest agreement was for C. albicans (Kappa: 0.851 - p<0.05) but no significant agreement for C. lusitaniae, C. krusei and C. guilliermondii was obtained (p>0.05). The agreement was significant for all identified species when RAPD (OPE-18) and API 20C AUX (p<0.05) were used. Critical levels of agreement between RAPD and microculture were observed when C. lusitaniae, C. krusei and C. guilliermondii were identified. Conclusions: API 20C AUX presented the best agreement with molecular random identification and CHROMagar showed good agreement for C. albicans, C. tropicalis, C. dubliniensis and C. krusei identification.
Abstract in English:Aim: To evaluate enamel microhardness and morphology after bleaching with hydrogen peroxide containing calcium in different concentrations. Methods: One hundred specimens of human teeth were ground and polished and had the initial microhardness evaluated. The specimens were randomly assigned into five groups (n=20): Group 1 - Control group (no treatment); Group 2 - Home Peroxide 6% (without calcium); Group 3 - Home Peroxide 7.5% (without calcium); Group 4 - White Class 6% (with calcium); Group 5 - White Class 7.5% (with calcium). For each group, the bleaching was performed according to the manufacturer's specifications. The specimens were bleached once a day for 5 days and subjected to pH cycling. Microhardness and scanning electron microscopy (SEM) analysis were performed before and after bleaching. Results: The results showed that groups submitted to bleaching treatment presented hardness loss compared to the control group. The group of 7.5% hydrogen peroxide with calcium showed a lower percentage of hardness loss in relation to other groups. Conclusion: Calcium in association with a higher hydrogen peroxide concentration may decrease microhardness changes on enamel.
Abstract in English:Aim: To determine the relationship between the chemical composition of saliva, periodontal disease and dental calculus. Methods: An observational analytical cross-sectional study was conducted with patients over 55 years of age. Ethical principles of autonomy and risk protection were applied according to the international standards. Sociodemographic and diagnosis variables (presence of dental calculus and periodontal status) were considered to measure salivary concentrations of glucose (by the glucose oxidase/peroxidase method, amylase (by the colorimetric test), urea (by the amount of indophenol), total protein (by the Bradford method) and albumin (by the nephelometric method). Patients chewed a sterile rubber band and 3 mL of stimulated saliva were collected. The samples were stored at -5 °C, centrifuged at 2,800 rpm for 10 min, and the supernatant was removed and stored at -20 °C. Data were presented as frequencies and proportions for qualitative variables and measures of central tendency and dispersion for quantitative variables. Data were analyzed by either analysis of variance or Kruskal Wallis test . A p value <0.05 was considered statistically significant. Results: Significant relationships were observed between the concentration of salivary urea and periodontal status (p = 0.03) and the presence of dental calculus and urea (p = 0.04) was demonstrated. Conclusions: A relationship between the salivary urea concentration and the presence of periodontal disease and dental calculus is suggested.
Abstract in English:Despite the increasing demand for fiber-reinforced composite (FRC) posts, their bonding to root canals is still subject to debate. Endodontic sealers may affect the bond strength between fiber posts and root canal dentin. Aim: To compare the effects of different sealers on fiber post bond strength. Methods: Sixty teeth were divided into 4 groups according to obturation method: GI, gutta-percha without any sealers; GII, gutta-percha and AH26 resin-based sealer; GIII, RealSeal point and RealSeal resin-based sealer, GIV, Guttaflow. Fiber posts were cemented into root canals. Specimens were sectioned, and the bond strength was measured in the middle area. The failure mode was evaluated. Data were analyzed by one-way ANOVA and post hoc test. Results: The highest bond strength was observed in the control group (2.95±1.12), and the least was in the Guttaflow group (1.15±0.78). There was a significant difference between bond strengths of the control and Guttaflow groups and between AH26 and Guttaflow groups (p<0.05). The failure mode was mainly adhesive between dentin and resin cement in all groups. Conclusions: Sealers may have a negative effect on the bond strength of fiber posts to root canal dentin.
Abstract in English:Jobs that require great responsibility can cause serious damage to the body such as stress and its consequences. Stress can be one of the triggers of disease systemic and oral diseases in different professionals. Aim: To associate emotional stress with the systemic and oral alterations in the nurses of public referral hospital. Methods: All 60 nurses of both genders, with higher education level, different ethnicities and ages were invited to join this study. Nurses filled out the Inventory of Stress Symptoms for Adults (ISSL) and questionnaire of diseases/psychosomatic symptoms. Next, they were subjected to a stomatological examination of the oral cavity, according to the Boraks (1996) criteria. Stress was associated with most outstanding psychosomatic and oral variables by the Fisher's exact test for calculating the p value (0.05). Results: The sample was comprised of 37 nurses, most of them female (91.9%), young (83.7% are less than 36-years old), full range 22-50 years old, white ethnicity (86.5%). The level of stress in level II (resistance) and III (exhaustion) was observed in 51.3% of the nurses. Symptoms of headache and gain of body weight lately were present in 48.6% of the nurses. With regard to oral alterations, 32.4% reported cold sore sometimes and 59.5% nibbled mucosa always. There was no significant association between the stress and psychosomatic and oral variables. Conclusions: Based on the results of this study it may be concluded that the nursing profession can lead to emotional stress, although no significant association between stress and disease/psychosomatic and oral symptoms was found. Future studies should be performed to evaluate this association.
Abstract in English:Aim: To compare the electromyographic activity and the asymmetry index among degrees of severity of temporomandibular disorders (TMD). Methods: Surface electromyography (EMG) of the right and left masseter and temporalis muscles was performed in 126 undergraduate students at rest and at maximal voluntary contraction. Three measurements were performed for five seconds of maximal contraction and mandibular rest. The degree of temporomandibular dysfunction was identified according to the Fonseca anamnestic index. The analysis of the asymmetry index for two pairs of muscles during maximal voluntary contraction was based on the asymmetry index proposed by Naeije, McCarrol and Weijs (1989). Results: 48.41% of the sample had mild TMD, followed by volunteers without TMD (26.98%), moderate TMD (19.05%) and severe (5.56%). The survey results show absence of correlation between the Fonseca anamnestic index and electromyographic activity at rest and at maximal voluntary contraction in undergraduate students in both muscles (p>0.05) and the asymmetry index did not differ between the analyzed groups. Conclusions: For the population of undergraduate students, there is no evidence that the presence and severity of TMD influence the EMG activity of masseter and temporalis muscles and the muscle asymmetry index at rest and maximal voluntary contraction.