Scielo RSS <![CDATA[Brazilian Oral Research]]> vol. 31 num. lang. en <![CDATA[SciELO Logo]]> <![CDATA[Accuracy of mandibular measurements of sexual dimorphism using stabilizer equipment]]> Abstract The objective of this investigation was to compare the accuracy of mandibular measurements using a stabilizer (MS) with gold standard computed tomography (GS) images. Sixty mandibles were studied. Werth TomoScope HV Compact® was used to obtain CT images (GS), and the MS was also used. Analysis of the CT scans was performed using the VG Studio Max software® (Volume Graphics GmbH, Heidelberg, Germany), and MS was used after the proper positioning of the mandible. Descriptive and paired t test measures were used, and a ROC curve was calculated, as well as sensibility and specificity. MedCalc and STATA 13.0® were used (95% level of significance). Bicondylar breadth, bicoronoid breadth and minimum ramus breadth reached the highest concordance correlation coefficients at 0.99 (0.99-1.00), 0.99 (0.99–1.00) and 1.00 (0.99–1.00), respectively. Comparing observers with GS, the lowest accuracy was noted for the maximum mandibular length [0.59 (0.45–0.69), 0.64 (0.51–0.74)], the breadth of the right (0.14 (0.04–0.23), 0.14 (0.004–0.24)) and left mandibular body [0.14 (0.03–0.24), 0.16 (0.05-0.26)], and the right [0.58 (0.45–0.69), 0.63 (0.51–0.73) and left (0.59 (0.45–0.70), 0.59 (0.46–0.69)] mandibular angle. Various measurements exhibited good sensibility for males using MS: maximum mandibular length (78.12), bicondylar breadth (78.12), left mandibular notch breadth (84.37), and the left height of the mandibular body at the mental foramen (75.00). High specificity in discriminating females was observed for the left maximal ramus height (85.19), mandibular length (85.71), bicoronoid breadth (96.43), right height of the mandibular body at the mental foramen (82.19), bimental breadth (78.57), breadth right (92.86) and left (96.43) mandibular body, minimum ramus breadth (89.29), and left mandibular angle (85.71). MS was able to discriminate sexual dimorphism. <![CDATA[Antimicrobial activity of ozone and NaF-chlorhexidine on early childhood caries]]> Abstract An early childhood carie (ECC) is an extremely destructive form of tooth decay. The aim of this study was to investigate the action of ozone (O3), and the association of sodium fluoride (NaF) with chlorhexidine (CHX) on bacteria related to ECC. Overnight culture of the bacteria was performed. On exponential phase the suspension was adjusted (101-108 CFU/mL). A drop (10μL) of each concentration of bacteria was applied on sheep blood agar plates and treated with O3 (2, 20, 200, and 2,000 ppm); after 18 hours, recovery analysis of CFU verified the reduction of bacterial activity. For NaF-CHX, sterile 96-well plates were prepared and divided into groups: G1 (150 µL TSB); G2 (20 µL of bacteria + 25 µL CHX + 25 µL NaF); and G3 (150 µL TSB + 20 µL of bacteria + 50 µL water). The plates were verified by analysis of the optical density (0, 12, 14, 16, and 18 hours). The data from O3 test were submitted to ANOVA and Tukey’s test (p &lt; 0.05). For the data from NaF-CHX, the ANOVA 2-way and Bonferroni’s test (p &lt; 0.05) were used. The number of CFU/mL showed death &gt; 3log10 (99.9%) for all bacteria (ozone ≥ 20ppm), while the combination of NaF-CHX was more effective (p &lt; 0.001) compared to each substance tested alone and the control group. The antimicrobial agents tested were able to inhibit all bacteria tested; O3 seemed to be a good alternative for controlling progression of carious lesions, while the association of NaF-CHX showed to be a good antimicrobial with easy and inexpensive application. <![CDATA[Evaluation of dentin hypersensitivity treatment with glass ionomer cements: A randomized clinical trial]]> Abstract A randomized, double-blind, split-mouth clinical trial was performed compared the desensitizing efficacy of the resin-modified glass ionomer cement (GIC) ClinproTM XT (3M ESPE, Minnesota, USA) and the conventional GIC Vidrion R (SS White, Gloucester, UK) in a 6-month follow-up. Subjects were required to have at least two teeth with dentin hypersensitivity. Teeth were divided at random into 2 groups, one group received Clinpro XT and the other conventional GIC Vidrion R. Treatments were assessed by tactile and air blast tests using Visual Analogue Scale (VAS) at baseline, after 20 minutes, and at 7, 15, 21, 30, 90 and 180 days post-treatment. Twenty subjects (152 teeth) were included. Both tests (tactile and air blast) showed a significant reduction of dentin hypersensitivity immediately after the application of Vidrion R and Clinpro XT (20 min). VAS scores obtained along the 6-month follow-up were statistically lower when compared to initial rates (p &lt; 0.05). Both GIC were able to reduce dentin hypersensitivity up to 6-month post-treatment period without statistically significant differences among them (p &gt; 0.05). Both cements provided satisfactory results in long-term dental sensitivity reduction. <![CDATA[One-year aging effects on microtensile bond strengths of composite and repairs with different surface treatments]]> Abstract The present study aimed to evaluate effects of different surface treatments and aging of composite cylinders on bond strength of composite resin repair. Thirty-two composite cylinders were produced and divided into four groups according to type of surface treatment and storage time of composite cylinder and repair. Cylinder surface of control group (Gcontrol) received no treatment before composite repair. Other groups were sandblasted with aluminum oxide (GAl2O3), followed by silane (GAl2O3sil) or adhesive (GAl2O3ad). Composite cylinders were stored in artificial saliva for either 24 hours or 1 year. Repairs were performed and stored in artificial saliva for 24 hours or 1 year and repair strength was evaluated using microtensile bond strength test. Data were submitted to Student’s t test, two-way ANOVA, and post hoc test for storage time and treatment (α = 0.05). Gcontrol group showed lower values of aging of composite cylinder and storage time of repair (24 hours or 1 year for both) compared with other groups (p &lt; 0.05). GAl2O3ad and GAl2O3sil groups did not exhibit decreased microtensile bond strength with aged repairs (1 year; p &gt; 0.05). Polymer degradation was significant for composite cylinders during the first year of storage in Gcontrol, GAl2O3, and GAl2O3ad groups (p &lt; 0.05). In GAl2O3sil group, storage time of composite cylinders was not significant (p &gt; 0.05). Aging of composite resin influenced bond strength of restoration repair for up to 1 year. Sandblasting with Al2O3, followed by application of silane layer, produced high bond strength after composite or repair aging. <![CDATA[The efficacy of low-level 940 nm laser therapy with different energy intensities on bone healing]]> Abstract The aim of this study was to evaluate the efficacy of low-level 940 nm laser therapy with energy intensities of 5, 10 and 20 J/cm2 on bone healing in an animal model. A total of 48 female adult Wistar rats underwent surgery to create bone defects in the right tibias. Low-level laser therapy (LLLT) was applied immediately after surgery and on post-operative days 2, 4, 6, 8, 10 and 12 in three study groups with energy intensities of 5 J/cm2, 10 J/cm2 and 20 J/cm2 using a 940 nm Gallium-Aluminium-Arsenide (Ga-Al-As) laser, while one control group underwent only the tibia defect surgery. All animals were sacrificed 4 or 8 weeks post-surgery. Fibroblasts, osteoblasts, osteocytes, osteoclasts and newly formed vessels were evaluated by a histological examination. No significant change was observed in the number of osteocytes, osteoblasts, osteoclasts and newly formed vessels at either time period across all laser groups. Although LLLT with the 10 J/cm2 energy density increased fibroblast activity at the 4th week in comparison with the 5 and 20 J/cm2 groups, no significant change was observed between the laser groups and the control group. These results indicate that low-level 940 nm laser with different energy intensities may not have marked effects on the bone healing process in both phases of bone formation. <![CDATA[Association between the clinical severity of oral lichen planus and anti-TPO level in thyroid patients]]> Abstract This study considered a possible relationship between the severity of oral lichen planus (OLP), serum anti-TPO autoantibodies (TPOAb) titer and thyroid disease in OLP patients. Forty-six OLP patients with positive TPOAb results (&gt; 35 IU/ml) who had also been diagnosed with thyroid disease were included in the study group. The control group consisted of 46OLP patients with no thyroid disease. The study and control groups (92) were divided to two subgroups of erosive OLP (EOLP) and non-erosive OLP (NEOLP). Serum TPOAb levels and IL-8 (to measure OLP severity) were evaluated using the independent t-test, chi-square and conditional logistic regression analysis (α = 0.05). A significant positive correlation was found between serum IL-8 and TPOAb levels in the study group (r = 0.783; p = 0.001). The positive blood levels of TPOAb were significantly associated with an increased risk of EOLP (OR = 4.02 at 95%CI; 1.21–13.4; p = 0.023). It is possible to used positive serum TPOAb levels in patients with OLP as in indicator of possible undetected thyroid disorders in those patients. Because erosive OLP has been associated with TPOAb in thyroid patients, it may be useful to determine TPOAb levels of such patients to diagnose a possible undetected thyroid disorders and follow-up for malignancy. <![CDATA[BPI-fold (BPIF) containing/plunc protein expression in human fetal major and minor salivary glands]]> Abstract The aim of this study was to determine expression, not previously described, of PLUNC (palate, lung, and nasal epithelium clone) (BPI-fold containing) proteins in major and minor salivary glands from very early fetal tissue to the end of the second trimester and thus gain further insight into the function of these proteins. Early fetal heads, and major and minor salivary glands were collected retrospectively and glands were classified according to morphodifferentiation stage. Expression of BPI-fold containing proteins was localized through immunohistochemistry. BPIFA2, the major BPI-fold containing protein in adult salivary glands, was detected only in the laryngeal pharynx; the lack of staining in salivary glands suggested salivary expression is either very late in development or is only in adult tissues. Early expression of BPIFA1 was seen in the trachea and nasal cavity with salivary gland expression only seen in late morphodifferentiation stages. BPIFB1 was seen in early neural tissue and at later stages in submandibular and sublingual glands. BPIFA1 is significantly expressed in early fetal oral tissue but BPIFB1 has extremely limited expression and the major salivary BPIF protein (BPIFA2) is not produced in fetal development. Further studies, with more sensitive techniques, will confirm the expression pattern and enable a better understanding of embryonic BPIF protein function. <![CDATA[Effects of periodontal treatment on primary sjȫgren’s syndrome symptoms]]> Abstract The aim of this longitudinal prospective study was to evaluate the effects of periodontal treatment on the clinical, microbiological and immunological periodontal parameters, and on the systemic activity (ESSDAI) and subjective (ESSPRI) indexes in patients with primary Sjögren’s Syndrome (pSS). Twenty-eight female patients were divided into four groups: pSS patients with or without chronic periodontitis (SCP, SC, respectively), and systemically healthy patients with or without chronic periodontitis (CP, C, respectively). Periodontal clinical examination and immunological and microbiological sample collection were performed at baseline, 30 and 90 days after nonsurgical periodontal treatment (NSPT). Levels of interleukin IL-1β, IL-8 and IL-10 in saliva and gingival crevicular fluid (GCF) were evaluated by ELISA, as well as the expression of Porphyromonas gingivalis (Pg), Aggregatibacter actinomycetemcomitans, (Aa) Tannerella forsythia (Tf), and Treponema denticola (Td), by qPCR. Systemic activity and pSS symptoms were evaluated by ESSDAI and ESSPRI. NSPT resulted in improved periodontal clinical parameters in both SCP and CP groups (p&gt;0.05). Pg, Aa, and Tf levels decreased after NSPT only in CP patients (p&lt;0.05). Significantly greater levels of IL-10 in GCF were verified in both SCP and CP groups (p&lt;0.05). SCP patients showed increased salivary flow rates and decreased ESSPRI scores after NSPT. In conclusion, NSPT in pSS patients resulted in improved clinical and immunological parameters, with no significant effects on microbiological status. pSS patients also showed increased salivary flow and lower ESSPRI scores after therapy. Therefore, it can be suggested that NSPT may improve the quality of life of pSS patients. <![CDATA[IL-6 and IL-10 gene polymorphisms in patients with aggressive periodontitis: effects on GCF, serum and clinic parameters]]> Abstract Genetic variations observed in cytokines affect periodontitis susceptibility. The aim of this study was to investigate interleukin(IL)-6(-174) and IL-10(-597) gene polymorphisms in generalized aggressive periodontitis (GAgP) patients. Also, we aimed to evaluate the effects of IL-6 and IL-10 gene polymorphisms on the clinical outcomes of non-surgical periodontal therapy and cytokine levels in gingival crevicular fluid(GCF) and serum. Fifty-three patients with GAgP and 50 periodontally healthy individuals were included in this study. Clinical parameters, GCF and blood samples were collected at baseline and at 6-week. Non-surgical periodontal therapy was performed in patients with GAgP. Gene analysis were determined by PCR-RFLP(polymerase chain reaction-restriction fragment length polymorphism) and cytokine levels were determined by enzyme-linked immunosorbent assay(ELISA).GAgP patients showed significant improvement on clinical parameters after periodontal therapy(p&lt;0.05). In the GAgP group, IL-6 GG genotype and G allele frequency were higher than in the control group. GCF IL-6 level was also significantly lower at 6-week in the GAgP group. Higher GCF IL-10 levelswere observed in patients carrying the IL-6 GG genotype than in those carrying the GC+CC genotype at baseline. In conclusion, IL-6(-174) and IL-10(-597) gene polymorphisms were found to be associated with GAgP and genotype distribution did not affect the outcome of non-surgical periodontal therapy, while patients with IL-6(-174) GG genotype had higher levels of GCF IL-10 levels. <![CDATA[Factors for determining dental anxiety in preschool children with severe dental caries]]> Abstract The aim of this study was to assess the clinical and socioeconomic indicators associated with dental anxiety in preschool children with severe dental caries. A total of 100 children between 3 and 5 years of age were selected during a dental screening procedure. The selection criteria were having at least one tooth with dental caries and a visible pulpal involvement, ulceration, fistula, and abscess (PUFA) index of ≥1 in primary teeth. Before the clinical examination or any treatment procedure was performed, we evaluated the children’s dental anxiety using the Facial Image Scale (FIS). Parents completed a questionnaire on socioeconomic conditions, which included the family structure, number of siblings, parental level of education, and family income. A dentist blinded to FIS and socioeconomic data performed the clinical examination. Poisson regressions associate clinical and socioeconomic conditions with the outcome. Most of the children (53%) experienced extensive dental caries (dmf-t ≥ 6), and all children had severe caries lesions, with a PUFA index of ≥1 in 41% and that of ≥2 in 59%. The multivariate adjusted model showed that older children (4–5-year old) experienced lower dental anxiety levels compared with younger children (3-year old) (RR = 0.35; 95%CI: 0.17–0.72 and RR = 0.18; 95%CI: 0.04–0.76, respectively), and children with three or more siblings were associated with higher levels of dental anxiety (RR = 2.27; 95%CI: 1.06–4.87). Older age is associated with low dental anxiety, and more number of siblings is associated with high dental anxiety in preschool children, whereas the severity or extent of dental caries is not associated with dental anxiety. <![CDATA[Risk factors, hyposalivation and impact of xerostomia on oral health-related quality of life]]> Abstract To determine xerostomia-related frequency, factors, salivary flow rates and Oral Health-Related Quality of Life (OHRQoL) of patients attending the Universidad Andrés Bello Dental School Clinic, in the city of Viña del Mar, Chile. The study involved 566 patients assessed with xerostomia, based on a single standardized questionnaire. The severity and impact of xerostomia on OHRQoL was assessed using a visual analogue scale (VAS) and the short version of the Oral Health Impact Profile Questionnaire (OHIP-14sp), respectively. Stimulated and non-stimulated salivary flow rates were obtained from a sample of patients. Xerostomia was reported in 61 patients (10.8%), comprising 50 women (83.3%) and 11 men (16.7%) (p &lt; 0.013). The prevalence was 13% among the women and 6.1% among the men. Gender, age and medication were found to be independent risk factors for the development of xerostomia. Hyposalivation was found in 10 of the 35 patients with xerostomia (28.6%) and in 2 patients without it (p &lt; 0.011). Patients with xerostomia had a reduced OHRQoL, compared with patients without xerostomia, as shown by the total OHIP-14sp score (p &lt; 0.001). Xerostomia was a common, potentially debilitating condition with a major impact on the OHRQoL of a patient population attending a university-based dental clinic. Hyposalivation was present in almost 30% of the patients who complained of xerostomia. It is important that general dentists be aware of this condition, so that they can provide patients with a good diagnosis, treatment and follow-up. <![CDATA[Influence of solvents on the bond strength of resin sealer to intraradicular dentin after retreatment]]> Abstract This study evaluated the removal of filling material with ProTaper Universal Rotary Retreatment system (PTR) combined with solvents and the influence of solvents on the bond strength (PBS) of sealer to intraradicular dentin after canal reobturation. Roots were endodontically treated and distributed to five groups (n = 12). The control group was not retreated. In the four experimental groups, canals were retreated with PTR alone or in combination with xylol, orange oil, and eucalyptol. After filling material removal, two specimens of each group were analysed by SEM and µCT to verify the presence of filling remnants on root canal walls. The other roots were reobturated and sectioned in 1-mm-thick dentin slices that were subjected to the push-out test. Data were analysed by two-way ANOVA and Tukey’s test (α = 0.05). SEM and µCT analysis revealed that all retreatment techniques left filling remnants on canal walls. The control group (3.47 ± 1.21) presented significantly higher (p &lt; 0.05) PBS than the experimental groups. The groups retreated with PTR alone (2.59 ± 0.99) or combined with xylol (2.54 ± 0.77) and orange oil (2.32 ± 0.93) presented similar bond strength (p &gt; 0.05), and differed significantly from the group with eucalyptol (1.89 ± 0.63). The solvents reduced the PBS of the sealer to dentin and no retreatment technique promoted complete removal of filling material. <![CDATA[Effects of platelet-rich fibrin on healing of intra-bony defects treated with anorganic bovine bone mineral]]> Abstract Anorganic bovine bone mineral (ABBM) is extensively used in the treatment of intra-bony defects. Platelet-rich fibrin (PRF) is a new-generation platelet concentrate with a simplified technique. Although certain studies have reported the use of PRF in the treatment of intra-bony defects, to date, none of them have evaluated its additive effects with ABBM. Therefore, a randomised, split-mouth clinical trial was conducted to compare healing of intra-bony defects treated with an ABBM-PRF combination with healing of those treated with ABBM alone. By using a split-mouth design, 15 paired intra-bony defects were randomly treated with either ABBM alone (control group) or ABBM-PRF combination (test group). Following clinical parameters and radiographical measurements were recorded at baseline and 6 months after treatment: plaque index (PI), gingival index (GI), probing depth (PD), gingival recession (GR), clinical attachment level (CAL), vertical bone loss, depth of defect and defect angle. Preoperative clinical and radiographical measurements were similar for the test and control groups. Statistically significant reductions in GI, PD, CAL, vertical bone loss, depth of intra-bony defect and widening of defect angle were detected after treatment in both groups. With respect to inter-group analysis, gain in CAL was significantly greater in the test group than in the control group, whereas no inter-group differences were observed in any other parameter. The results of this study indicate that both therapies are effective in the treatment of intra-bony defects. <![CDATA[PAR-2 expression in the gingival crevicular fluid reflects chronic periodontitis severity]]> Abstract Recent studies investigating protease-activated receptor type 2 (PAR-2) suggest an association between the receptor and periodontal inflammation. It is known that gingipain, a bacterial protease secreted by the important periodontopathogen Porphyromonas gingivalis can activate PAR-2. Previous studies by our group found that PAR-2 is overexpressed in the gingival crevicular fluid (GCF) of patients with moderate chronic periodontitis (MP). The present study aimed at evaluating whether PAR-2 expression is associated with chronic periodontitis severity. GCF samples and clinical parameters, including plaque and bleeding on probing indices, probing pocket depth and clinical attachment level, were collected from the control group (n = 19) at baseline, and from MP patients (n = 19) and severe chronic periodontitis (SP) (n = 19) patients before and 6 weeks after periodontal non-surgical treatment. PAR-2 and gingipain messenger RNA (mRNA) in the GCF of 4 periodontal sites per patient were evaluated by Reverse Transcription Polymerase Chain Reaction (RT-qPCR). PAR-2 and gingipain expressions were greater in periodontitis patients than in control group patients. In addition, the SP group presented increased PAR-2 and gingipain mRNA levels, compared with the MP group. Furthermore, periodontal treatment significantly reduced (p &lt;0.05) PAR-2 expression in patients with periodontitis. In conclusion, PAR-2 is associated with chronic periodontitis severity and with gingipain levels in the periodontal pocket, thus suggesting that PAR-2 expression in the GCF reflects the severity of destruction during periodontal infection. <![CDATA[Osteogenic potential of periodontal ligament stem cells are unaffected after exposure to lipopolysaccharides]]> Abstract Periodontitis develops as a result of a continuous interaction between host cells and subgingival pathogenic bacteria. The periodontium has a limited capacity for regeneration, probably due to changes in periodontal ligament stem cells (PDLSCs) phenotype. The aim of this study was to evaluate the effects of lipopolysaccharides from Porphyromonas gingivalis (PgLPS) on mesenchymal phenotype and osteoblast/cementoblast (O/C) potential of PDLSCs. PDLSCs were assessed for Toll-like receptor 2 (TLR2) expression by immunostaining technique. After, cells were exposed to PgLPS, and the following assays were carried out: (i) cell metabolic activity using MTS; (ii) gene expression for IL-1β, TNF-α and OCT-4 by real-time polymerase chain reaction (RT-qPCR); (iii) flow cytometry for STRO-1 and CD105, and (iv) osteogenic differentiation. PDLSCs were positive for TLR2. PgLPS promoted cell proliferation, produced IL-1β and TNF-α, and did not affect the expression of stem cell markers, STRO-1, CD105 and OCT-4. Under osteogenic condition, PDLSCs exposed to PgLPS showed a similar potential to differentiate toward osteoblast/cementoblast phenotype compared to control group as revealed by mineralized matrix deposition and levels of transcripts for RUNX2, ALP and OCN. These results provide evidence that PgLPS induces pro-inflammatory cytokines, but does not change the mesenchymal phenotype and osteoblast/cementoblast differentiation potential of PDLSCs. <![CDATA[Short implants to support mandibular complete dentures - photoelastic analysis]]> Abstract This study evaluated the stress behavior around short implants in edentulous atrophic mandibles. Six groups included implants with two diameters regular and wide (4 and 5 mm) and three lengths (5, 7 and 9 mm) as follows: Ci9 (9 x 4 mm), Ci7 (7 x 4 mm), Ci5 (5 x 4 mm), Wi9 (9 x 5 mm), Wi7 (7 x 5 mm) and Wi5 (5 x 5 mm). These groups were compared to the control group CG (11 x 4 mm). The analysis was performed with the photoelastic method (n = 6). Each model comprised 4 implants with the same length and diameter connected by a chromium-cobalt bar that simulates a fixed denture. A 0.15 kg force was applied at the end of the cantilever (15 mm), and the maximum shear stress was recorded around the distal and subsequent implants. The stress values were determined, and the quantitative data (Fringes®) were submitted to statistical analysis with one-way ANOVA and the Dunnett test (p &lt; 0.05). It was observed that the reduction in implant length increased stress values with a significant difference (p &lt; 0.05) between CG Ci7 and Ci5, while the increase in implant diameter reduced the stress values without any differences found between short and long implants. Implants with 5 and 7 mm with regular diameter increased stress levels while short implants with larger diameters experienced similar stress to that of longer implants. <![CDATA[Expression of E-cadherin and involucrin in leukoplakia and oral cancer: an immunocytochemical and immunohistochemical study]]> Abstract To assess the immunocytochemical and immunohistochemical correlation of adhesion (E-cadherin) and cell differentiation (involucrin) molecules in oral leukoplakia and oral squamous cell carcinoma. Cytological samples and biopsies were obtained from male and female patients aged over 30 years with oral leukoplakia (n = 30) and oral squamous cell carcinoma (n = 22). Cell scrapings and the biopsy were performed at the site of the lesion and histological slides were prepared for the immunocytochemical analysis of exfoliated oral mucosal cells and for the immunohistochemical analysis of biopsy tissues using E-cadherin and involucrin. Spearman’s correlation and kappa coefficients were used to assess the correlation and level of agreement between the techniques. Immunostaining for E-cadherin and involucrin by both techniques was similar in the superficial layers of the histological sections compared with cell scrapings. However, there was no statistical correlation and agreement regarding the immunocytochemical and immunohistochemical expression of E-cadherin and involucrin in oral leukoplakia (R = 0.01, p = 0.958) (Kappa = 0.017, p = 0.92) or in oral squamous cell carcinoma (R = 0.26, p = 0.206) (Kappa = 0.36, p = 0.07). The immunoexpression of E-cadherin and involucrin in tissues is consistent with the expression patterns observed in exfoliated oral mucosal cells, despite the lack of a statistically significant correlation. There is an association of the histopathological characteristics of leukoplakia with the expression E-cadherin and of the microscopic aspects of oral squamous cell carcinoma with immunohistochemical expression of involucrin. <![CDATA[AmF/NaF/SnCl<sub>2</sub> solution reduces <em>in situ</em> enamel erosion – profilometry and cross-sectional nanoindentation analysis]]> Abstract This in situ study aimed to investigate the effect of a tin-containing fluoride solution in preventing enamel erosion. Also, its effects on the partly demineralized zone were assessed for the first time. Thirteen volunteers participated in this 2-phase study, wearing removable intra-oral appliances containing four sterilized bovine enamel slabs, for 8 days, where 2 treatment protocols were tested using samples in replicas (n = 13): CO - no treatment (negative control) and FL - AmF/NaF/SnCl2 solution (500 ppm F-, 800 ppm Sn2+, pH = 4.5). Samples were daily exposed to an erosive challenge (0.65% citric acid, pH 3.6, 4 min, 2x/day). In the 2nd phase, volunteers switched to the other treatment protocol. Samples were evaluated for surface loss using a profilometer (n = 13) and a cross-sectional nanohardness (CSNH) test (n = 13) was carried out in order to determine how deep the partly demineralized zone reaches below the erosive lesion. The data were statistically analyzed by two-way ANOVA. Erosive challenges lead to smaller enamel surface loss (p &lt; 0.001) in the FL group when compared to group CO. Data from CSNH showed that there was no significant difference in demineralized enamel zone underneath erosion lesions between the groups. An amorphous layer could be observed on the surface of enamel treated with tin-containing solution alone. Under the experimental conditions of this in situ study, it can be concluded that AmF/NaF/SnCl2 solution prevents enamel surface loss but does not change the hardness of the partly demineralized zone near-surface enamel. <![CDATA[Differentiation between palatal rugae patterns of twins by means of the Briñón method and an improved technique]]> Abstract Palatal rugae patterns are anatomic structures considered unique to each person. Monozygotic twins present similarities, however, Rugoscopy in particular, may contribute to their individualization for forensic purposes. The aims of this study were: to study the palatal rugae classifications of Briñón; to propose improvements to facilitate use of this method, if pertinent; and to characterize palatal rugae in a sample of Brazilian monozygotic twins and singletons. Precise reproducibility of the two methods of Briñón, from 1982 and 2011, was prevented by poor intra-examiner agreement (70% and 13% respectively). Our proposed improvements to these methods, although preliminary, were associated with better results. The most common palatal rugae patterns were types A, M, and Q. Palatal rugae were confirmed to be unique to each individual, even in monozygotic twins. Furthermore, twins did not exhibit any special patterns that might facilitate their differentiation from singletons.