Scielo RSS <![CDATA[Brazilian Oral Research]]> vol. 26 num. 4 lang. en <![CDATA[SciELO Logo]]> <![CDATA[<b>Challenges of managing a public university</b>]]> <![CDATA[<b>The influence of interdental spacing on the detection of proximal caries lesions in primary teeth</b>]]> The aim of this study was to investigate the influence of interdental spacing on the performance of proximal caries detection methods in primary molars. In addition, aspects related to temporary tooth separation with orthodontic separators were evaluated. The proximal spaces between the posterior primary teeth (n = 344) of 76 children (4-12 years old) were evaluated before and after temporary separation. Stainless steel strips with different standardized thicknesses were used to measure the presence of biological spacing and the spacing obtained after temporary separation with orthodontic rubber rings. First, the presence of proximal caries lesions was assessed by visual inspection, bitewing radiographs and a pen-type laser fluorescence device (DIAGNOdent pen). Visual inspection after temporary separation with separators was the reference standard method in checking the actual presence of caries. Multilevel analyses were performed considering different outcomes: the performance of the methods in detecting caries lesions and the spacing after temporary separation. The spacing did not influence the performance of the caries detection methods. The maximum spacing obtained with temporary tooth separation was 0.80 mm (mean ± standard deviation = 0.46 ± 0.13 mm). The temporary separation was more effective in the upper arch and less effective when an initial biological interdental spacing was present. The biological interdental spacing does not influence the performance of proximal caries detection methods in primary molars, and temporary tooth separation provides spacing narrower than 1.0 mm. <![CDATA[<b>The effect of iron on <i>Streptococcus mutans</i> biofilm and on enamel demineralization</b>]]> Iron (Fe) may have an anticaries effect by specific inhibition of glycosyltransferase (GTF) enzymes of Streptococcus mutans, but this hypothesis has not yet been clarified. In this study, S. mutans biofilms were formed on blocks of bovine dental enamel of a predetermined surface hardness (SH). These biofilms were exposed eight times/day to 10% sucrose, and two times/day they were subjected to one of the following treatments: G1, 0.9% NaCl as a negative control; G2, 0.12% chlorhexidine digluconate (CHX) as a positive antibacterial control; G3, 0.05% NaF (225 ppm F) as a positive anticaries control; G4, G5, and G6, ferrous sulfate (Fe2+) at concentrations of 1.0, 10.0, and 100.0 µg Fe/mL, respectively. The experiment was performed in triplicate and was repeated three times (n = 9). The pH of the culture medium was determined every 24 h as an indicator of the biofilm's acidogenicity. The biofilm formed on each block was collected for determination of the viable bacteria and concentration of extracellular polysaccharides (EPS). Enamel SH was again determined and the percentage of SH loss (%SHL) was calculated as an indicator of demineralization. Iron treatment reduced the number of viable bacteria formed in the S. mutans biofilm (p = 0.04), in a dose-dependent manner, and also reduced the enamel's %SHL (p = 0.005). At 100 µg/mL, Fe reduced enamel demineralization as effectively as CHX and NaF (p < 0.05), but it did not inhibit EPS production. In conclusion, the data suggest that the anticaries mechanism of action of Fe may not involve the oxidative inhibition of GTFs. <![CDATA[<b>Eroded dentin does not jeopardize the bond strength of adhesive restorative materials</b>]]> This in vitro study evaluated the bond strength of adhesive restorative materials to sound and eroded dentin. Thirty-six bovine incisors were embedded in acrylic resin and ground to obtain flat buccal dentin surfaces. Specimens were randomly allocated in 2 groups: sound dentin (immersion in artificial saliva) and eroded dentin (pH cycling model - 3× / cola drink for 7 days). Specimens were then reassigned according to restorative material: glass ionomer cement (KetacTM Molar Easy Mix), resin-modified glass ionomer cement (VitremerTM) or adhesive system with resin composite (Adper Single Bond 2 + Filtek Z250). Polyethylene tubes with an internal diameter of 0.76 mm were placed over the dentin and filled with the material. The microshear bond test was performed after 24 h of water storage at 37ºC. The failure mode was evaluated using a stereomicroscope (400×). Bond strength data were analyzed with two-way ANOVA and Tukey's post hoc tests (α = 0.05). Eroded dentin showed bond strength values similar to those for sound dentin for all materials. The adhesive system showed the highest bond strength values, regardless of the substrate (p < 0.0001). For all groups, the adhesive/mixed failure prevailed. In conclusion, adhesive materials may be used in eroded dentin without jeopardizing the bonding quality. It is preferable to use an etch-and-rinse adhesive system because it shows the highest bond strength values compared with the glass ionomer cements tested. <![CDATA[<b><i>In vitro</i></b><b> analysis of the influence of surface treatment of dental implants on primary stability</b>]]> Surface treatment interferes with the primary stability of dental implants because it promotes a chemical and micromorphological change on the surface and thus stimulates osseointegration. This study aimed to evaluate the effects of different surface treatments on primary stability by analyzing insertion torque (IT) and pullout force (PF). Eight samples of implants with different surface treatments (TS - external hexagon with acid surface treatment; and MS - external hexagon, machined surface), all 3.75 mm in diameter X 11.5 mm in length, were inserted into segments of artificial bones. The IT of each sample was measured by an electronic torquemeter, and then the pullout test was done with a universal testing machine. The results were subjected to ANOVA (p < 0.05), followed by Tukey's test (p < 0.05). The IT results showed no statistically significant difference, since the sizes of the implants used were very similar, and the bone used was not highly resistant. The PF values (N) were, respectively, TS = 403.75 ± 189.80 and MS = 276.38 ± 110.05. The implants were shown to be different in terms of the variables of maximum force (F = 4.401, p = 0.0120), elasticity in maximum flexion (F = 3.672, p = 0.024), and relative stiffness (F = 4.60, p = 0.01). In this study, external hexagonal implants with acid surface treatment showed the highest values of pullout strength and better stability, which provide greater indication for their use. <![CDATA[<b>Assessment of ion diffusion from a calcium hydroxide-propolis paste through dentin</b>]]> This study evaluated the ability of ions from a non-alcoholic calcium hydroxide-propolis paste to diffuse through dentinal tubules. Thirty-six single-rooted bovine teeth were used. The tooth crowns were removed, and the root canals were instrumented and divided into 3 groups: Group 1 - calcium hydroxide-propylene glycol paste; Group 2 - calcium hydroxide-saline solution paste; Group 3 - calcium hydroxide-propolis paste. After the root canal dressings were applied, the teeth were sealed and placed in containers with deionized water. The pH of the water was measured after 3, 24, 72 and 168 hours to determine the diffusion of calcium hydroxide ions through the dentinal tubules. All of the pastes studied promoted the diffusion of calcium hydroxide ions through the dentinal tubules. Associating propolis to calcium hydroxide resulted in a pH increase, which occurred with greater intensity after 72 hours. The calcium hydroxide-propolis paste was able to diffuse in dentin. <![CDATA[<b>Influence of prior 810-nm-diode intracanal laser irradiation on hydrophilic resin-based sealer obturation</b>]]> Dentin wall structural changes caused by 810-nm-diode laser irradiation can influence the sealing ability of endodontic sealers. The objective of this study was to evaluate the apical leakage of AH Plus and RealSeal resin-based sealers with and without prior diode laser irradiation. Fifty-two single-rooted mandibular premolars were prepared and divided into 4 groups, according to the endodontic sealer used and the use or non-use of laser irradiation. The protocol for laser irradiation was 2.5W, continuous wave in scanning mode, with 4 exposures per tooth. After sample preparation, apical leakage of 50% ammoniacal silver nitrate impregnation was analyzed. When the teeth were not exposed to irradiation, the RealSeal sealer achieved the highest scores, showing the least leakage, with significant differences at the 5% level (Kruskal-Wallis test, p = 0.0004), compared with AH Plus. When the teeth were exposed to the 810-nm-diode laser irradiation, the sealing ability of AH Plus sealer was improved (p = 0282). In the RealSeal groups, the intracanal laser irradiation did not interfere with the leakage index, showing similar results in the GRS and GRSd groups (p = 0.1009). <![CDATA[<b>Analysis of 153 cases of odontogenic cysts in a South Indian sample population</b>: <b>a retrospective study over a decade</b>]]> The purpose of this study was to determine the prevalence of odontogenic cysts and to identify their clinico-pathological features among patients by studying biopsy specimens obtained from the archives of the Department of Oral and Maxillofacial Pathology, College of Dental Sciences, Davangere, Karnataka, India, during the past 10 years. Data for the study were retrieved from the case records of patients fitting the histological classification of the World Health Organization (1992). Analyzed clinical variables included age, gender, anatomical location, and histological diagnosis. Of the 2275 biopsy reports analyzed, 194 cases (8.5%) were jaw cysts, including odontogenic (6.7%) and nonodontogenic cysts (0.25%). Odontogenic cysts included 69.3% radicular, 20.3% dentigerous, 5.2% keratinizing odontogenic, 3.3% residual, and 1.9% other cysts, such as lateral periodontal, botryoid odontogenic, and gingival cysts. The most frequent clinical manifestation was swelling, followed by a combination of pain and swelling. Age, gender, and location were related to the etiopathologic characteristics of the cyst type. A definitive diagnosis can be made on the basis of clinical, radiological, and histological findings, which makes a good interdepartmental relationship between the clinicians and pathologists essential. Knowledge of the biological and histological behavior of the odontogenic cysts is required for their early detection and treatment. <![CDATA[<b>Inflammatory root resorption in primary molars: prevalence and associated factors</b>]]> This study aimed at determining the prevalence of inflammatory root resorption and associated factors in 1068 primary mandibular molars in 453 children 3 to 12 years of age. Age, dental history and medical history were recorded using a questionnaire administered to the children's parents/caregivers. Previously trained and calibrated examiners assessed radiographic images of the primary molars by direct observation, with the aid of a viewing box. Root resorption (physiological or inflammatory), dental crown status (healthy, carious with no pulp involvement, carious with pulp involvement and evidence of restoration), and pulpotomy or pulpectomy were determined. Data analysis involved descriptive statistics, the chi-square test and a multiple logistic regression (p < 0.05). The prevalence of inflammatory root resorption was 16.2% (n = 173). The male gender (OR: 1.4; 95% CI), the 3-to-7-years age bracket (OR: 1.5; 95% CI), an unhealthy dental crown (OR: 8.7; 95% CI), caries with pulp involvement (OR: 7.4; 95% CI), pulpotomy (OR: 3.1; 95% CI), and pulpectomy (OR: 5.4; 95% CI) were risk factors for the occurrence of inflammatory root resorption in primary molars. In conclusion, the prevalence of inflammatory root resorption in the present sample was 16.2%. Gender, age, an unhealthy tooth, caries with pulp involvement, pulpotomy, pulpectomy, and the absence of a restoration were associated with a higher occurrence of inflammatory root resorption in primary molars. <![CDATA[<b>Detection of simulated incipient furcation involvement by CBCT</b>: <b>an <i>in vitro</i> study using pig mandibles</b>]]> The aim of the present study was to test the reproducibility, sensitivity, and specificity of cone-beam computed tomography (CBCT) in detecting incipient furcation involvement. Fifteen macerated pig mandibles, with intact second molar teeth and preserved adjacent cortical areas, were used. Simulated lesions were created in the furcation region of these teeth by applying 70% perchloric acid in up to four possible buccal/lingual sites in the right/left sides of each mandible. The mandibles were then submitted to a CBCT scan. Two blinded and calibrated experienced oral and maxillofacial radiologists interpreted the exams. Furcation involvement was also assessed in the regions without simulated lesions. CBCT showed high levels of accuracy, ranging from 78% to 88%. The variations in Kappa values for intra- and inter-observer agreement (0.41-0.59) were considered moderate. CBCT can be considered a reliable and accurate method for detecting incipient furcation involvement. <![CDATA[<b>Effects of temporal muscle detachment and coronoidotomy on facial growth in young rats</b>]]> This study analyzed the effects of unilateral detachment of the temporal muscle and coronoidotomy on facial growth in young rats. Thirty one-month-old Wistar rats were distributed into three groups: detachment, coronoidotomy and sham-operated. Under general anesthesia, unilateral detachment of the temporal muscle was performed for the detachment group, unilateral coronoidotomy was performed for the coronoidotomy group, and only surgical access was performed for the sham-operated group. The animals were sacrificed at three months of age. Their soft tissues were removed, and the mandible was disarticulated. Radiographic projections-axial views of the skulls and lateral views of hemimandibles-were taken. Cephalometric evaluations were performed, and the values obtained were submitted to statistical analyses. There was a significant homolateral difference in the length of the premaxilla, height of the mandibular ramus and body, and the length of the mandible in all three groups. However, comparisons among the groups revealed no significant differences between the detachment and coronoidotomy groups for most measurements. It was concluded that both experimental detachment of the temporal muscle and coronoidotomy during the growth period in rats induced asymmetry of the mandible and affected the premaxilla. <![CDATA[<b>Evaluation of the cell block technique as an auxiliary method of diagnosing jawbone lesions</b>]]> This study investigated the viability of the cell block technique as an auxiliary method of diagnosing jawbone lesions. Thirty-three clinically diagnosed jawbone lesions with a cystic appearance were subjected to aspiration. The aspirated material was processed by the cell block technique, and the lesions were biopsied and treated. Cytological findings (cell block) and histopathology analyses (gold standard) were compared by the chi-square test. There were associations between cysts and cholesterol crystal clefts, between keratocystic odontogenic tumors (KOT) and epithelial cells, and between KOT and parakeratin. The occurrence of cholesterol crystal clefts in cell block slides was correlated with cystic lesions, and the parakeratin presence was a KOT indicator. The cell block technique proved to be fast, easy-to-handle, and low-cost, making it an attractive auxiliary method for the preliminary diagnosis of jawbone lesions. <![CDATA[<b>Randomized clinical controlled trial on the effectiveness of conventional and orthodontic manual toothbrushes</b>]]> The objective of this study was to compare the effectiveness of two manual toothbrushes (conventional and orthodontic). The following clinical parameters were used: VPI (visible plaque index) and GBI (gingival bleeding index). Patients, 64 total (30 males and 34 females), in the permanent dentition, with a mean age of 17.8 years, were randomly selected from a practice specializing in orthodontics. Each participant received audio-visual instructions on oral hygiene as well as a kit of materials containing two manual toothbrushes (orthodontic and conventional). Each toothbrush was randomly allocated to one side of the mouth (split-mouth design) and used for a period of approximately 4 weeks. The VPI and GBI were measured by a single calibrated examiner before (T0) and after (T1) the implementation of interventions. The Mann-Whitney test was used to compare the VPI values between the groups, and the Student t-test for independent samples was used to compare GBI values. The level of significance was set at 5%. No statistically significant difference was observed between the groups at T0 for both VPI and GBI, and at T1 for the GBI. The manual orthodontic toothbrush produced a statistically lower VPI (P < 0.05) at T1, but this did not seem to be of clinical importance. <![CDATA[<b>Effect of non-surgical periodontal treatment on the subgingival microbiota of patients with chronic kidney disease</b>]]> This study investigated the effect of non-surgical periodontal therapy on the composition of subgingival microbiota of patients with chronic kidney disease (CKD). Sixteen CKD pre-dialysis individuals (CKD) and 14 individuals without clinical evidence of kidney disease (C) presenting chronic periodontitis were treated by scaling and root planing. Subgingival samples were collected from each patient and analyzed for their composition by checkerboard at baseline and 3 months post-therapy. Significant differences between groups at baseline were sought by the Mann-Whitney and χ² tests. Changes over time were examined by the Wilcoxon test. At baseline, the CKD group had significantly lower counts of E. faecalis compared to the C group (p < 0.05). After treatment, the levels of a greater number of species were reduced in the C group. Higher levels of A. israelii, C. rectus, F. periodonticum, P. micra, P. nigrescens, T. forsythia, N. mucosa, and S. anginosus (p < 0.05) were found in the CKD group compared to the C group. Also, non-responsive sites in CKD individuals harbored significantly higher levels of pathogenic species (T. forsythia, P. gingivalis, T. denticola, Fusobacterium spp., D. pneumosintes, E. faecalis and S. aureus; p < 0.05) than sites that responded to therapy, as well as non-responsive sites in the C group. The periodontitis-associated subgingival microbiota of CKD and systemically healthy individuals was similar in composition. However, high levels of pathogenic species persisted in the subgingival microbiota of patients with CKD after treatment. <![CDATA[<b>Stromal myofibroblasts in focal reactive overgrowths of the gingiva</b>]]> Focal reactive overgrowths are among the most common oral mucosal lesions. The gingiva is a significant site affected by these lesions, when triggered by chronic inflammation in response to microorganisms in dental plaque. Myofibroblasts are differentiated fibroblasts that actively participate in diseases characterized by tissue fibrosis. The objective of this study was to evaluate the presence of stromal myofibroblasts in the main focal reactive overgrowths of the gingiva: focal fibrous hyperplasia (FFH), peripheral ossifying fibroma (POF), pyogenic granuloma (PG), and peripheral giant cell granuloma (PGCG). A total of 10 FFHs, 10 POFs, 10 PGs, and 10 PGCGs from archival specimens were evaluated. Samples of gingival mucosa were used as negative controls for stromal myofibroblasts. Oral squamous cell carcinoma samples, in which stromal myofibroblasts have been previously detected, were used as positive controls. Myofibroblasts were identified by immunohistochemical detection of alpha smooth muscle actin (α-sma). Myofibroblast immunostaining was qualitatively classified as negative, scanty, or dense. Differences in the presence of myofibroblasts among FFH, POF, PG, and PGCG were analyzed using the Kruskal-Wallis test. Stromal myofibroblasts were not detected in FFH, POF, PG, or PGCG. Consequently, no differences were observed in the presence of myofibroblasts among FFH, POF, PG, or PGCG (p > 0.05). In conclusion, stromal myofibroblasts were not detected in the focal reactive overgrowths of the gingiva that were evaluated, suggesting that these cells do not play a significant role in their pathogenesis. <![CDATA[<b>Influence of core-finishing intervals on tensile strength of cast posts-and-cores luted with zinc phosphate cement</b>]]> The core finishing of cast posts-and-cores after luting is routine in dental practice. However, the effects of the vibrations produced by the rotary cutting instruments over the luting cements are not well-documented. This study evaluated the influence of the time intervals that elapsed between the cementation and the core-finishing procedures on the tensile strength of cast posts-and-cores luted with zinc phosphate cement. Forty-eight bovine incisor roots were selected, endodontically treated, and divided into four groups (n = 12): GA, control (without finishing); GB, GC, and GD, subjected to finishing at 20 minutes, 60 minutes, and 24 hours after cementation, respectively. Root canals were molded, and the resin patterns were cast in copper-aluminum alloy. Cast posts-and-cores were luted with zinc phosphate cement, and the core-finishing procedures were applied according to the groups. The tensile tests were performed at a crosshead speed of 0.5 mm/min for all groups, 24 hours after the core-finishing procedures. The data were subjected to one-way analysis of variance (ANOVA) and Tukey's test (α = 0.05). No significant differences were observed in the tensile strengths between the control and experimental groups, regardless of the time interval that elapsed between the luting and finishing steps. Within the limitations of the present study, it was demonstrated that the core-finishing procedures and time intervals that elapsed after luting did not appear to affect the retention of cast posts-and-cores when zinc phosphate cement was used.