Resumo em Inglês:

AIM: To evaluate and compare the perception of parents of children with and without disabilities about the occurrence of local and systemic manifestations during the eruption of primary teeth and to investigate the parents' practices used to alleviate teething disturbances. METHODS: A cross-sectional study was conducted in a sample of parents of children without disabilities (GI) and parents of children with disabilities (GII) treated at a University Pediatric Dentistry Clinic. Data from GI and GII were collected using a structured questionnaire applied during an interview with the parents, and were analyzed using descriptive statistics. Mann-Whitney and Wilcoxon tests were employed and the level of significance was set at p<0.05. RESULTS: The questionnaires were filled out by 86 parents, being 45 in GI and 41 in GII. For GI, the most frequent local manifestations were edema around the tooth (84.44%) and increased suction (75.56%); and for GII were edema and erythema around the tooth (78.05% and 70.73%, respectively). The most frequent systemic manifestations, according to parents of both groups, were irritability and fever. There was no statistically significant difference between groups (p<0.05). It was observed that 46.66% and 68.3% of parents of GI and GII, respectively, adopted different practices to alleviate teething disturbances. CONCLUSIONS: During primary teeth eruption, local and systemic manifestations may occur and different practices were adopted by the Interviewed parents, mainly those with children with disabilities.

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AIM: To biomechanically analyze two fixation techniques in polyurethane hemi-mandibular body fractures, using a universal testing machine. METHODS: The study employed 10 polyurethane hemi-mandible replicas, which simulated simple fractures of the mandibular body, divided into two groups: one group comprised 5 hemi-mandibles with two 2.0 mm system plates in the tension and compression zones, while the other group contained 5 hemi-mandibles with an Erich bar and a 2.0 mm system plate in the tension and neutral zones, respectively. Data were analyzed statistically by the Student's t-test (α=0.05) RESULTS: The test results indicated that the fixation using 2.0 mm system plates offered significantly more resistance to the loads and presented significantly larger displacement compared to the fixation using just one 2.0 mm system plate and the Erich bar. CONCLUSIONS: It may be concluded that the use of two plates in the 2.0 mm system had greater mechanical strength than a single 2.0 mm plate combined with an Erich bar. Clinically, it is known that both techniques can provide good results, but patients receiving the combination of Erich bar and one plate are required to be more cooperative during the postoperative period, especially with respect to the prescribed diet in order to avoid failures in this system.

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AIM: To evaluate the influence of plaster condition, dry or not, on the amount of residual monomer in heat-cured acrylic resin. METHODS: Thirty acrylic resin specimens (65x10x3 mm) were fabricated and randomly assigned to 5 groups (n=6). The evaluated resins were heat-cured acrylic resins by conventional or microwave polymerization techniques and the plaster was previously dried in microwave oven in two groups. Each specimen was individually immersed in a test tube containing methanol (7 days) for surface analysis. In the groups for which internal monomer was evaluated, the specimens were fragmented and the small fragments were weighed prior to immersion in methanol. The analysis was made by high performance liquid chromatography (HPLC). Data were analyzed by ANOVA and Tukey test (p<5%) RESULTS: showed statistical differences among the groups. CONCLUSIONS: The previous plaster drying influenced the residual monomer amount showing a decrease of these levels.

Resumo em Inglês:

AIM: To evaluate the cytotoxicity of several storage media (coconut water, whole milk, isotonic solution, Hank´s Balanced Salt Solution and tap water) using a multiparametric cytotoxicity analysis employing 3T3 cells. METHODS: Plates containing confluent 3T3 fibroblasts were exposed to the various media for 24h, at 37°C with 5% CO2, and cell viability was evaluated by a multiparametric assay assessing sequentially, on the same cells, mitochondrial activity (XTT), membrane integrity (neutral red test), and total cell density (crystal violet dye exclusion test). Results from each test were compared by one-way analysis of variance (ANOVA). RESULTS: Statistical analysis showed that whole milk and HBSS were the most effective media in maintaining cell viability at all tested times (p<0.05). Isotonic and tap water showed the highest cytotoxicity effects. CONCLUSIONS: This study shows that whole milk and HBSS are more efficient in maintaining the viability of 3T3 fibroblasts as demonstrated by three different cell viability tests.

Resumo em Inglês:

As far as the periimplant anatomy is considered, the question raised is whether or not healthy periimplant tissues present bleeding on probing (BOP). AIM: To assess if the criterion BOP is strictly related to periimplant disease (PID). METHODS: 134 patients were included in this study. All periimplant regions were clinically and radiographically evaluated. Patients were assigned to 3 groups based on radiographic and clinical aspects in the periimplant region: Group A (healthy-sites) - no signs of mucosal inflammation or bone loss; Group B (mucositis) - red and swollen mucosa, but no radiographic bone loss; Group C (periimplantitis) - radiographically confirmed pathological bone loss. After this classification, all periimplant sulci were probed at 4 sites (mesial, distal, buccal, lingual/palatal). Patients' mean age was 51.7±12.4 years, 77 women and 57 men, with a total of 486 osseointegrated endosseous implants. RESULTS: Groups A and C showed significant difference in age and implant region distribution (p=0.009 and p=0.008, respectively). After initial clinical and radiographic diagnosis of periimplant status, 33 (20.1%) regions showed BOP in group A. All regions in Group B presented BOP. In Group C, 41 (19.9%) regions showed no BOP. All groups differed significantly considering BOP as diagnosis parameter (p<0.0001). CONCLUSIONS: BOP was always present in inflamed mucosa, but it was not always absent in healthy mucosa. Not all periimplantitis regions showed BOP. Clinical and radiographic aspects must always be considered together for diagnosis of PID, even if BOP is absent.

Resumo em Inglês:

AIM: To compare marginal seal at tooth-material and material-material interfaces in the proximal box in combined amalgam/composite resin restorations. METHODS: Mesio-occlusal-distal (MOD) cavities were prepared in 35 premolars and permanent molars with carbide bur. The distal proximal box was restored with amalgam (Permite, SDI) until reaching the height of pulpal floor. Dental tissues were etched with 37% acid and a bonding agent (Bond 1-SF, Pentron) was applied and cured. Composite resin (Filtek Z250, 3M-ESPE) was placed in layers in the mesial proximal box and occlusally, and light cured. Marginal adaptation was evaluated at the following interfaces: amalgam-tooth (A), amalgam-composite resin (AC) and composite resin-tooth (C). Microleakage was evaluated by means of methylene blue infiltration after 7-day water storage and thermocycling regimen (1500 cycles). Microleakage was assessed as percentage depth of horizontal dye penetration. RESULTS: ANOVA showed statistically significant difference between A-AC and A-C (p<0.01). No statistically significant difference was found between AC-C interfaces (p>0.05). Mean microleakage values were A (73.529/28.71), AC (34.118/34.6) and C (40.435/34.965), according to Tukey's test. CONCLUSIONS: Although the bonding mechanism between amalgam and composite has not yet been completely explained, amalgam/composite resin interface exhibited the lowest microleakage scores. Since amalgam/composite resin restorations exhibited lower microleakage scores than composite resin on the cervical surface, combined restorations can be considered as a biological and aesthetic alternative to conventional Class II composite or amalgam restorations.

Resumo em Inglês:

AIM: To investigate the association between palatally impacted maxillary canines (PIC) and idiopathic osteosclerosis. METHODS: A sample of 54 subjects (28 females and 26 males, mean age of 12.98±1.59 years) with PIC was selected from the records of 1,650 orthodontic patients treated at the Discipline of Orthodontics clinics at the Dental School of the Pontifical Catholic University of Paraná (PUCPR), in Curitiba, PR, Brazil. A control group of 54 subjects with normally erupted canines was also selected from the same files (mean age of 12.93±1.58 years). Panoramic, lateral skull, postero-anterior skull, periapical and occlusal radiographs, as well as stone casts of the patients were examined. The Kolmogorov-Smirnov test revealed a normal distribution of gender and age in the groups. The results were analyzed with the Chi-square test (α=0.05). RESULTS: There were no statistically significant differences (p>0.05) between the groups. Four patients from each group had idiopathic osteosclerosis (7.41%), a rate that falls in the prevalence range reported in the literature. CONCLUSIONS: No correlation was observed between palatally impacted maxillary canines and idiopathic osteosclerosis.

Resumo em Inglês:

Dentists' incorrect behavior with regards to Oral Radiology, as reported in the literature, has been related to inadequate training of undergraduates. AIM: This study assessed dental undergraduates' knowledge of Oral Radiology. METHODS: A questionnaire containing 30 questions pertaining to three domains - General Principles, Radiobiology/Radioprotection and Technique/Interpretation - was used as data collection instrument. A total of 195 students answered the questionnaires. RESULTS: No statistically significant differences were found between second-, third- and fourth-year students (p>0.05) when the whole questionnaire and the General Principles domain (p>0.05) were considered. The Technique/Interpretation domain presented a borderline statistical significance level (p=0.051), with more correct answers attributed to second-year students. A statistically significant difference (p<0.05) was seen for the Radiobiology/Radioprotection domain, in which the fourth-year students performed better. CONCLUSIONS: Dental undergraduates' knowledge of Oral Radiology did not increase or decrease significantly comparing the undergraduate years. However, with the exception of the Technique/Interpretation domain, students of more advanced undergraduate years answered more correctly the questions. Nevertheless, the Technique/Interpretation domain should be reinforced throughout the undergraduate course.

Resumo em Inglês:

AIM: To evaluate the human enamel permeability after different external bleaching techniques. METHODS: The coronal portions of 20 maxillary human incisors were covered with an acid resistant varnish, except the labial surface, to prevent dye penetration of silver nitrate. The specimens were divided randomly into four groups (n=5) according to the bleaching treatments: Group 1 (G1) - without bleaching agent (control group), Group 2 (G2) - 35% hydrogen peroxide (HP) - one session of three 10-min applications, Group 3 (G3) - 35% HP - 2 sessions of three 10-min applications, and Group 4 (G4) - 6% HP - 14 days (1h/day). G1 was exposed to artificial saliva only and in the other groups the bleaching agents were applied following the manufacturers' recommendations. After bleaching, teeth were immersed in a 50% silver nitrate solution for 2 h and photodeveloped for 16 h. Then, three longitudinal slices of each tooth were photographed by an optical microscope (100x). The degree of dye penetration was analyzed in the middle third of the dental crowns using a 0 to 4 score system (0= no dye penetration, 1= less than half the enamel thickness, 2= half of the enamel thickness, 3= full extent of enamel without reaching the dentin, and 4= tracer agent reaching dentin). The data were analyzed statistically by the Kruskal-Wallis and Dunn tests (α=0.05). RESULTS: The median (1st/3rd interquartiles) ranges were: G1: 0(0/0), G2: 2(2/3), G3: 3(3/3) and G4: 3(3/3). G2, G3 and G4 showed significantly higher dye penetration compared with G1 (p=0.0017). CONCLUSIONS: The use of bleaching agents increased dental enamel permeability, regardless of the bleaching technique.

Resumo em Inglês:

AIM: To evaluate the leakage on Er,Cr:YSGG laser- and bur- prepared Class V cavities restored with a silorane-based composite resin using different insertion techniques METHODS: 40 cavities were outlined according to: the type of instrument [Er,Cr:YSGG laser (3.0 W power, energy per pulse of 150 mJ, fluence of 53.57J/cm², pulse duration of 140-200 ∝s, 20 Hz repetition rate and 55/65% air/water spray) or diamond bur]; and the type of filling technique (bulk increment or incremental). Four experimental groups were obtained (n=10): G1- diamond bur (DB) and incremental (I); G2- DB and bulk increment (BI); G3- Er,Cr:YSGG and I; and G4- Er,Cr:YSGG and BI. Specimens were restored with a silorane-based composite resin (Filtek P90, 3M/ESPE), subjected to 500 thermal cycles, sealed, infiltrated with 2% (w/v) methylene blue and sectioned in halves. Specimen analysis was scored based on a scale. Statistical analyses were done using the Kruskal-Wallis and Student Newman-Keuls tests (α=0.05). RESULTS: Statistically significant differences were observed between G2 and G4 (p=0.003) and between G1 and G2 (p=0.028). The filling technique did not influence the pattern of dye leakage in the cavity walls (p=0.151). CONCLUSIONS: Less leakage was observed when Er,Cr:YSGG cavities were restored with silorane-based composite resin, using the bulk increment technique. Nevertheless, cavities done using diamond bur have less leakage only when incrementally restored.

Resumo em Inglês:

AIM: To evaluate the oral conditions of patients with chronic kidney disease undergoing dialysis and to determine the influence of dialysis duration and bone metabolism on the prevalence and severity of the alterations found. METHODS: The simplified oral hygiene index (OHI-S), prevalence of dental caries (decayed, missing filled teeth index, DMFT), and the periodontal screening and recording (PSR) index were evaluated in 154 patients. Parathyroid hormone (PTH), calcium, phosphorus and urea measurements, as well as panoramic radiographs, were obtained from all patients. To evaluate the effect of duration of dialysis treatment on oral health, the patients were divided into two groups: (1) <5 years and (2) > 5 years. Regarding blood levels of PTH, patients were divided into three groups: (1) 0-149 pg/mL, (2) 150-584 pg/mL, and (3) >585 pg/mL. The OHI-S identified the accumulation of biofilm and calculus around the teeth. RESULTS: Gingival inflammation was found in 100% of dentate patients, with 2 being the predominant PSR score (72.3%). The DMFT index was high (17.52). Dental calculus was the most common radiographic finding (70.8%). No significant correlation was observed between dialysis duration, biochemical alterations, and oral health. CONCLUSIONS: Most patients undergoing dialysis presented precarious oral hygiene, periodontal inflammation, and bone alterations. However, these manifestations were not influenced by the duration of dialysis or bone metabolism.

Resumo em Inglês:

AIM: The primary aim of this longitudinal study was to evaluate additional effects of 4-week chlorhexidine digluconate (CHX) gel treatments to control Aggregatibacter actinomycetemcomitans counts in children after professional dental prophylaxis. Porphyromonas gingivalis and Streptococcus mutans counts were also determined to evaluate the secondary effects of anti-plaque treatments on microbial shifts. METHODS: Twenty-six children with A. actinomycetemcomitans counts >4 log10/mL of saliva and/or Quigley-Hein plaque index >3.0 were enrolled in this study. Patients were randomly assigned to groups GI (placebo gel), GII (0.5% CHX gel), GIII (1% CHX gel), and GIV (2% CHX gel). Four sessions of treatment were performed during 4 weeks after a session of professional dental prophylaxis. Real-Time polymerase chain reaction (PCR) was used to determine viable microorganism counts in non-stimulated whole saliva samples collected at baseline, one week, one month and three months after interruption of treatments. RESULTS: A reduction of all bacterial counts was detected after the 3-month follow-up in all groups. Lower counts of P. gingivalis were achieved from 1 week on after treatments. The 2% CHX concentration seemed to contribute to lower A. actinomycetemcomitans levels and increase S. mutans levels. CONCLUSIONS: Professional dental prophylaxis was effective to control salivary levels of A. actinomycetemcomitans, P. gingivalis and S. mutans. Additional antimicrobial effects, however, were not observed by the combination of professional dental prophylaxis and 4-week chlorhexidine gel treatments.

Resumo em Inglês:

AIM: To compare the effectiveness of different obturation techniques in surpassing the ledge formed in simulated curved root canals. METHODS: Eighty acrylic-resin blocks with curved canals were instrumented with Gates-Glidden drills to simulate a ledge formation. Then, a K-File #10 was used for trying to surpass the deviation, and the blocks that permitted surpassing were rejected. The remaining blocks were divided into 4 groups according to the obturation technique: lateral condensation, Tagger's Hybrid technique, Thermafil and System B. The blocks had their images digitalized using a scanner before and after the obturation procedures. The images were analyzed with Image Tool 3.0 software. Statistical analysis was performed by one-way ANOVA at a significant level of 5%. RESULTS: The System B resulted in the highest obturated area (p<0.001). There were no significant differences between the Tagger's Hybrid technique and Thermafil system regarding the effectiveness in surpassing ledge (p>0.05). The lateral condensation resulted in the worst ability in filling the ledge space (p<0.001). CONCLUSIONS: Within the limitations of this study, it was possible to conclude that techniques using heat condensation or gutta-percha thermoplastification were more effective in surpassing the ledge formed in curved canals than the lateral condensation.

Resumo em Inglês:

AIM: To evaluate the proliferative capacity of mesenchymal cells derived from human periodontal ligament on polished and plasma-treated titanium surfaces. METHODS: Eighteen titanium disks were polished and half of them (n=9) were submitted to plasma nitriding using the cathodic cage technique. Mesenchymal cells were isolated from periodontal ligament of impacted third molars (n=2) and cultured on titanium disks (polished and nitrided) and on a plastic surface as a positive control of cell proliferation. Cell proliferation was analyzed and growth curves were constructed for the different groups by determining the number of cells adhered to the different surfaces at 24, 48 and 72 h after plating. RESULTS: Higher cell number was observed for the nitrided surface at 24 and 48 h. However, no statistically significant difference in cell proliferation was observed between the two different surface treatments (p>0.05). CONCLUSIONS: We concluded that plasma nitriding produced surfaces that permitted the proliferation of human periodontal ligament mesenchymal cells. Associated to other physical and chemical properties, it is possible to assume the feasibility of plasma nitriding method and its positive effect on the early cellular events of osseointegration.

Resumo em Inglês:

AIM: This in vitro study evaluated the effect of using a dental hypersensitivity treatment on the bond strength to dentin of etch-and-rinse and self-etching simplified adhesive systems. METHODS: 40 healthy molars were used. The crowns of teeth were removed at the dentinoenamel junction, and remaining roots were sectioned in the mesiodistal direction along their long axis, separating the buccal and lingual/palatal halves. The segments obtained were ground, keeping the buccal or lingual/palatal face turned downwards in order to flatten the surface and produce a standardized smear layer. Prepared specimens were randomly distributed into 4 groups (n=10), according to the combination of surface treatment with the desensitizing dentifrice Colgate Sensitive Pro-Relief (Colgate Palmolive®) (test group - with dentifrice and control group - without dentifrice) and type of simplified bonding agent (etch-and-rinse and self-etching agents). Resin composite blocks were fabricated on the dentin surfaces, after application of bonding agents, and specimens were sectioned into rectangular stick-shaped specimens with cross-sectional area of approximately 0.8mm². For microtensile bond strength tests, 4 sticks were randomly selected from the central region of specimens, and fixed to a universal test machine. Data were analyzed statistically by the Mann-Whitney U test (a=0.05). RESULTS: The bond strength obtained in the group without desensitizer (control) + etch-and-rinse agent was significantly higher compared with the other groups. Under both experimental conditions, the self-etching agent showed weak bond strength to dentin. CONCLUSIONS: Change in the dentin substrate by obliteration of tubules in the process of relieving dentinal sensitivity could reduce the bond strength of simplified etch-and-rinse and self-etching bonding agents.