Abstract in English:The aim of the present study was to evaluate two dental curricula at a school of dentistry in southern Brazil. The study population included dentists trained in the last two classes of the institution's old curriculum (n = 98) and graduates of the first two classes of the new curriculum (n = 56). A questionnaire with open and closed questions was used for an overall evaluation of different aspects of the curricula, such as study methods, importance given to basic sciences, quality of theoretical and clinical guidance, perception about skills needed to perform different dental procedures, professional goals and an overall assessment. Students in the new curriculum reported more frequent use of the internet (69.6%) and scientific articles (50.0%). More importance was given to the basic sciences in the new curriculum. Graduates of the old curriculum alleged themselves to be more capable of both performing conventional (99%) and complex amalgam restorations (68.4%), as well as three-unit fixed prostheses (62.2%). Graduates of the new curriculum alleged higher capability with periodontal surgeries (48.2%), treatment of temporomandibular joint (TMJ) disorders (58.1%) and public health planning (78.6%). Regarding professional goals, the new curriculum was associated with an increase in the graduates' willingness to work in the public health system and to pursue an academic career. New curriculum graduates reported higher overall assessments regarding their educational, as well as theoretical and clinical, outcomes. A new curricular approach was associated with several changes from the perspective of the students.
Abstract in English:The purpose of the present study was to assess the bond strength of composite resin repairs subjected to different surface treatments and accelerated artificial aging. 192 cylindrical samples (CSs) were prepared and divided into 24 groups (n = 8). Half of the CSs were stored in water for 24 h, and the other half were subjected to C-UV accelerated aging for non-metallic specimens. The treatments were phosphoric acid + silane + adhesive (PSA); phosphoric acid + adhesive (PA); diamond bur + phosphoric acid + silane + adhesive (DPSA); diamond bur + phosphoric acid + adhesive (DPA); air abrasion + phosphoric acid + silane + adhesive (APSA); and air abrasion + phosphoric acid + adhesive (APA). The repair was performed and the specimens were again aged as described above. A control group (n = 8) was established and did not receive any type of aging or surface treatment. The specimens were loaded to failure in shear mode with a crosshead speed of 0.5 mm/min until fracture. Data were analyzed by one-way ANOVA/Tukey's test (p < 0.05). No statistically significant differences were found among DPSA, DPA, APSA, APA, and the control group. The aged PSA and PA achieved low bonding values and were statistically different from the control group, whereas the non-aged PSA and PA presented no statistically significant difference from the control group. Repairs with the proposed surface treatments were viable on both recent and aged restorations; however, phosphoric acid + adhesive alone were effective only on recent restorations.
Abstract in English:Cordless retraction paste material for gingival retraction in implant dentistry has recently become of interest to the clinician. However, few studies have been conducted on the use of retraction pastes and their possible interaction with implant surfaces. This in vitro study evaluated the effect of a cordless retraction paste material, Expasyl® (Acteon), on TiUnite® (Nobel Biocare) implant surfaces. Three areas of the fixtures were evaluated before and after contact with the retraction paste using scanning electron microscopy to evaluate changes in surface topography and energy-dispersive spectroscopy to identify any surface chemistry modifications. Alteration of the initial surface after exposure to Expasyl® was identified, with the implant collar showing the most changes.
Abstract in English:Mononuclear cells play an important role in the modulation of healing. The characteristics of implant surface topography may alter the production of signaling molecules such as cytokines. The aim of this in vitro study was to evaluate the effects of commercially available titanium surface treatments on both cell viability and the secretion of the antagonist cytokines, IL1β and TGFβ1. Human mononuclear cells were cultured on 10 mm diameter commercially pure titanium (cpTi) disks that were prepared using a turning procedure (control=machined surface) and either acid etched or bio-anodized for 1-7 days. Adhered cells were investigated with respect to cell viability using an MTT assay, and cytokine production was verified using an ELISA assay. The results indicate that surface characteristics did not alter the cell viability at days 1 and 4, although the machined surface presented the highest absorbance values at day 7 (p = 0.0084). Cell viability was reduced throughout the time course for all analyzed surfaces (p < 0.05). On day 4, IL1β levels were significantly higher on bio-anodized compared to acid etched surfaces (p = 0.0097). TGFβ1 did not show differences among the surfaces at days 1 and 4. The responses of non-stimulated mononuclear cells to titanium surfaces suggest only modest effects of the surface treatment and roughness on pro-inflammatory cytokine (IL1β) release.
Abstract in English:The extent of separation between the maxillary and mandibular teeth in the fabrication of interocclusal splints designed to achieve efficiency and muscle relaxation is controversial and undefined in the literature. Based on this premise, the aim of this study was to evaluate the effect of interocclusal splint thicknesses of 3 and 6 millimeters on the electrical activity of the anterior temporal and masseter muscles during rest and dental clenching. Twenty asymptomatic individuals (10 males and 10 females) were selected using the Research Diagnostic Criteria (RDC). Electromyography (EMG) was performed both with and without the 3- and 6-mm splints using the Bio EMG software package, which recorded values given in microvolts (µV). The results, which were assessed using analysis of variance (ANOVA) to a 5% significance level (p < 0.05), showed increased electrical activity of the masticatory muscles during dental clenching compared with at rest, with greater activity in the masseter muscle. The electrical activity did not differ according to the thickness of the splints or between males and females. We can conclude that both splint thicknesses are effective in treating muscle hyperactivity given their similar clinical behavior for asymptomatic individuals.
Abstract in English:The aim of this study was to compare clinical staging and magnetic resonance imaging (MRI) staging for oral cancer, and to assess inter-observer agreement between oral and medical radiologists. A total of 10 patients diagnosed with oral cancer were assessed before treatment. A head and neck surgeon performed clinical TNM staging. Two medical radiologists and two oral radiologists performed a new staging assessment by interpreting MRI scans, without prior knowledge of the clinical staging. They evaluated the extent of the primary tumor (T), metastasis to regional lymph nodes (N) and grouping by stages. The data were analyzed using the Kappa Index. There was significant agreement (p < 0.05) between the clinical and MRI staging assessments made by one oral radiologist for N stage, and between those made by one medical radiologist for the T and N stages and for the grouping by stages. In the MRI assessment, there was significant agreement among all four observers for both T stage and grouping by stages. For the N stage, there was no significant agreement between one oral radiologist and one medical radiologist or between both medical radiologists. There was significant agreement among the remaining radiologists. There was no agreement between the clinical and MRI staging. These results indicate the importance of using MRI for the diagnosis of oral cancer. Training initiatives and calibration of medical and oral radiologists should be promoted to provide an improved multidisciplinary approach to oral cancer.
Abstract in English:Squamous cell carcinoma (SCC) is the most prevalent cancer of the oral cavity and the fifth most prevalent of all malignancies in males. Many researchers have attempted to develop new treatments that will improve the prognosis of SCC patients. Over 20% of the world's biodiversity is located within the Brazilian forests, but little is known about the chemical and/or pharmacological potential of these plants. Certain extracts obtained from Amazon and Atlantic Forest plants have previously been shown to have cytotoxic activity against various cancers. The aim of this study was to screen these extracts for cytotoxic activity against oral SCC cells. The extracts were analyzed for activity against the KB-ADL#12 cell line at various concentrations up to a maximum dose of 100 µg/mL. Comparisons with a control group were performed using one-way ANOVA. Significant cytotoxicity was induced by the extracts obtained from the aerial parts of Picrolemma sprucei (Simaroubaceae), from the leaves and stems of Laetia suaveolens (Salicaceae), from the aerial parts of Abarema auriculata (Fabaceae-Mimosoideae) and from the stem of A. auriculata.
Abstract in English:The aims of this study were to determine and compare frictional resistance obtained by low-friction and conventional elastomeric ligatures in the presence of artificial saliva, and observe whether this variable changed after 21 days. Super Slick® low-friction elastomeric ligatures and conventional ligatures of the brands TP conventional® and Unitek® were placed on standard edgewise maxillary central incisor metal brackets, slot .022" × .028" tying rectangular orthodontic wires .018" × .025". Three experimental groups were arranged according to the type of ligature and a control group in which no wires were used. The friction values obtained between the bracket/wire/ligature set were measured using a Universal Test Machine at a speed of 20 mm/minute, at two experimental time intervals: T0 - immediately after specimen fabrication; and T1 - 21 days after fabrication and immersion in artificial saliva at 37 ºC. Conventional Unitek ligatures and the low-friction ligature (Super Slick) showed the lowest friction values at T0. After 21 days (T1), however, conventional Unitek ligatures presented the lowest value. All groups assessed from T0 to T1 showed a numerical reduction in friction values, suggesting that time, heat and humidity may cause elastic degradation, however this was not verified statistically (P > 0.05).
Abstract in English:This cross-sectional study assessed the impact of Developmental Enamel Defects (DED) on Child Oral Health-Related Quality of Life (COHRQoL). A sample of 944 11- to 14-year-old Brazilian schoolchildren was examined for the prevalence and severity of DED. The children completed the Child Perceptions Questionnaire (CPQ11-14), and socioeconomic status was also collected using a questionnaire. Poisson regression models were used to assess the association between DED and overall and domain-specific CPQ11-14 scores. The prevalence of DED was 19.7%. In general, children with DED did not indicate any decrease in self-perception. However, this condition was associated with an impact on the functional limitation domain. The presence of DED may cause negative impacts on a child's perception of oral health and on their daily performance.
Abstract in English:The purpose of this study was to morphometrically evaluate the influence of different durations of ovariectomy-induced estrogen deficiency on alveolar bone loss associated with ligature-induced bone loss in rats. Sixty female Wistar rats were randomly assigned to ovariectomy (OVX test group) or sham operation (SHAM control group). The OVX and SHAM groups were each distributed into three subgroups of ten rats each according to the duration of estrogen deficiency (30, 60 and 90 postoperative days). In all groups, for the last 30 days of the experimental period, cotton ligatures were placed around the cervix of the right upper second molar; the contralateral tooth was left unligated to serve as a control. The maxillary bones were removed, and the alveolar bone loss was analyzed by measuring the distance between the cementoenamel junction and the alveolar bone crest at the buccal site of the right upper second molar. A comparison between the ligated and unligated groups verified the presence of ligature-induced alveolar bone loss (p < 0.05). No significant differences were observed among the unligated groups (p > 0.05). A significant increase in bone loss was observed when ligation occurred 90 days after ovariectomy compared with the sham group (p < 0.05). These results demonstrate that long-term estrogen deficiency affects ligature-induced alveolar bone loss.
Abstract in English:Leukemia has been associated with oral manifestations. However, the available literature on this topic consists of mostly reports of cases, without data about the periodontal parameters that may be under the influence of hematologic factors. The aim of this cross-sectional study was to assess the correlation between the Gingival Index and Bleeding on Probing with the platelet count in patients with leukemia. Patients with diagnosis of any kind of leukemia, at any stage of treatment, having a minimum age of 14 years, treated at the Department of Hematology-Oncology of the University Hospital of Santa Maria, Brazil, between December 2009 and March 2010, were assessed. Excluded patients were: edentulous, with orthodontic appliances, with psychomotor disturbances, requiring antibiotic prophylaxis for the examinations, or those using medications associated with gingival swelling. Two trained and calibrated examiners evaluated the Plaque Index, Gingival Index (GI), Probing depth, Bleeding on Probing (BOP), and Clinical Attachment Loss. Hematologic data were collected from a blood test performed on the same day as the periodontal examination. Thirty-seven patients (26 males), aged between 15 and 80 years (mean age 41.7 ± 18.31) were evaluated. Correlation between platelet count and BOP (p > 0.05), or between platelet count and GI (p > 0.05), were both weak (Pearson's correlation coefficient r = 0.171 and r = -0.003, respectively) and not statistically significant. It can be concluded from the preliminary results that the low platelet count was not correlated with the higher prevalence of gingival and periodontal bleeding in patients with leukemia.
Abstract in English:Salivary IgA can serve as a first line of defense against pathogens that colonize and invade mucosal surfaces and may be protective against periodontal disease. The aim of this study was to assess salivary immunoglobulin A levels in diabetic and non-diabetic patients with different periodontal treatment needs. The Periodontal Screening & Recording (PSR) system was used to evaluate the periodontal treatment needs of 41 diabetic and 42 non-diabetic patients. Unstimulated whole saliva was collected from each patient immediately before clinical examination and stored at -20 °C until analysis. Salivary immunoglobulin A (s-IgA) levels were determined using an enzyme-linked immunosorbent assay, and values were expressed as optical density. Diabetic and non-diabetic patients were compared using clinical and laboratory data. PSR data indicated that periodontal disease was more frequent and more severe in diabetic patients. A higher prevalence of codes 3 and 4 was observed in diabetics as compared with non-diabetics (odds ratio = 2, P < 0.05). Furthermore, non-diabetic patients had more healthy sextants (code 0) than did diabetic patients. Over half of diabetic patients (∼54%) presented with s-IgA levels that were lower than the normal range (optical density from 0.4 nm to 0.6 nm; P < 0.05). In addition, diabetic patients showed a higher variability in s-IgA levels as compared with non-diabetic patients. In conclusion, diabetic individuals had lower s-IgA levels, more-frequent and more-severe periodontal disease, and a greater need for periodontal treatment as compared with non-diabetic patients.
Abstract in English:Dental biofilm control represents a basic procedure to prevent caries and the occurrence of periodontal diseases. Currently, toothbrushes and dentifrices are used almost universally, and the employment of good oral hygiene allows for appropriate biofilm removal by both mechanical and chemical control. The aim of this study was to evaluate the effectiveness of adding vegetable or mineral oil to a commercially available dentifrice in dental biofilm control. A comparison using the Oral Hygiene Index Simplified (OHI-S) was performed in 30 individuals who were randomly divided into three groups. Group 1 (G1) received a commercially available dentifrice; the composition of this dentifrice was modified by addition of mineral oil (Nujol®) for group 2 (G2) or a vegetable oil (Alpha Care®) for group 3 (G3) at 10% of the total volume, respectively. The two-way repeated-measures analysis of variance (two-way ANOVA) was used to test the effect of group (G1, G2 and G3) or time (baseline, 45 days and 90 days) on the OHI-S index scores. Statistical analysis revealed a significant reduction in the OHI-S at day 90 in G2 (p < 0.05) and G3 (p < 0.0001) in comparison to G1. Therefore, the addition of a vegetable or a mineral oil to a commercially available dentifrice improved dental biofilm control, suggesting that these oils may aid in the prevention and/or control of caries and periodontal disease.
Abstract in English:Acid erosion is a superficial loss of enamel caused by chemical processes that do not involve bacteria. Intrinsic and extrinsic factors, such as the presence of acid substances in the oral cavity, may cause a pH reduction, thus potentially increasing acid erosion. The aim of this study was to evaluate the microhardness of bleached and unbleached bovine enamel after immersion in a soda beverage, artificial powder juice and hydrochloric acid. The results obtained for the variables of exposure time, acid solution and substrate condition (bleached or unbleached enamel) were statistically analyzed by the ANOVA and Tukey tests. It was concluded that a decrease in microhardness renders dental structures more susceptible to erosion and mineral loss, and that teeth left unbleached show higher values of microhardness compared to bleached teeth.