Brazilian oral research最新文献

This study aimed to assess the biomechanical behavior of reinforcement materials [cobalt chromium alloy (CoCr) and carbon fiber-reinforced polyether ether ketone (CFR-PEEK)] and their extensions (short: 15 mm and long: 25 mm) of single implant-retained mandibular overdentures (MO-1) by 3D finite element analysis (FEA), comparing them with MO-1 without a framework. Five models (CoCr-Short, CFR-PEEK-Short, CoCr-Long, CFR-PEEK-Long, and no framework) were created using the McNeel Rhinoceros 3D software, version 7.0. Stress distribution analysis by FEA was performed using the Optstruct solver, and a 30° oblique load (100 N) was applied in the anterior region (50 N on each central incisor). Biomechanical behavior was analyzed by overdenture displacement, maximum (MaxP) and minimum principal (MinP) stress, and von Mises stress. The MO-1 model 'without a framework' produced the largest dislocation, MinP stress on the mucosa, and MaxP stress in the cortical bone. Regardless of the extension of the framework, CFR-PEEK had minor MinP stress in the mucosa and lower overdenture displacement. The 'CoCr-Long' and 'CFR-PEEK-Long' models had higher von Mises stress on the implant housing, and MaxP stress on the O'ring nylon conventional implant and overdenture. The 'CoCr-Short' and ' CFR-PEEK-Short' models showed a greater tendency for tension concentration solely in the framework. The incorporation of a framework into MO-1 decreased stress concentration on the overdenture, resulting in lower stress on the attachment, mucosa, implant, and peri-implant bone, irrespective of the material used. The short framework, however, performed better biomechanically in MO-1, and it is therefore the most recommended option. CFR-PEEK showed favorable biomechanical outcomes, and is suggested for reinforcement of MO-1.

This study evaluated the microtensile bond strength (μTBS) and fracture pattern of direct composite resin reinforced with polyethylene fiber (Ribbond®) on dentin substrate after thermomechanical cycling (TMC). Dentin blocks (dentin thickness=2 mm) were obtained from forty human third molars and randomly divided into four groups (n=10) according to type of restoration (composite resin with or without Ribbond®) and to whether they were or were not subjected to TMC (100,000 cycles of 50 N / 2 Hz / 1-minute baths of 5 and 55ºC). The 1-mm-thick square-shaped specimens were submitted to μTBS testing in a universal testing machine at 0.5 mm/min. The fracture patterns were assessed by stereoscopic magnifying glass (30X magnification). The μTBS (in MPa) and failure pattern data were subjected to the generalized linear model and G tests (a=0.05). Neither the polyethylene fiber nor TMC had any statistically significant effect (p=0.196 and p=0.136, respectively) on the μTBS of the composite resin to dentin. Adhesive failures were more prevalent in the composite resin group compared with the Ribbond-containing group when subjected to TMC. Additionally, the composite resin containing Ribbond® showed a higher proportion of cohesive failures in composite resin than the resin groups not containing this fiber, irrespective of TMC. It was concluded that reinforcing the direct layer of composite resin with Ribbond® polyethylene fiber did not influence the adhesive resistance to dentin, even when subjected to TMC. However, its incorporation did result in a higher frequency of cohesive failures in resin after TMC.

This study carried out a critical review of the principles of radioprotection, including the ALARA, ALADA, and ALADAIP principles. The Google Scholar and PubMed databases were the search resources, and the following keywords were searched: Linear No-Threshold (LNT); Biologic Effects of Ionizing Radiation (BEIR VII); As Low As Reasonably Achievable (ALARA); As Low As Diagnostically Acceptable (ALADA); As Low As Diagnostically Acceptable, being Indication-oriented and Patient-specific (ALADAIP). This critical review included studies with historical references, reviews, position papers, and clinical and experimental studies. Regarding data extraction, only original articles were selected after the screening process. Much of the current evolution of X-ray machines and radioprotection protocols has stemmed from legitimate concerns about this topic. This development has grown out of the relevant work of organizations like ICRP, UNSCEAR, and other renowned international organizations. Low doses of radiation, such as those used for diagnosis, also occur naturally and are present in everyday life. Although there is no agreement on the actual risk involving low doses, the recommendations of ALARA, ALADA, and ALADAIP prevail, in line with the trend to uphold principles that balance the importance of X-ray diagnostic imaging with the intention of keeping the doses as low as possible. The benefits of X-ray exams, when justified, tend to outweigh the low risks attributed to them.

The aim of this study was to assess the impact of orthodontic treatment with orthodontic aligners (OAs) and fixed appliances (FAs) on oral health-related quality of life (OHRQoL). This parallel randomized clinical trial included 40 male and female patients aged 13 to 35 years diagnosed with Angle's Class I malocclusion. Participants were assigned to two groups: OA (n = 20) and FA (n = 20). OHRQoL was assessed using the Brazilian OHIP-14, which was administered before treatment (T0), at 1 month (T1), 6 months (T2), and 12 months (T3) after treatment initiation. Data were analyzed using the independent t test, the chi-square test, the Mann-Whitney test, and Friedman test (p < 0.05). FAs had a significantly (p < 0.05) higher impact on OHRQoL at T1 in terms of functional limitation, physical pain, psychological discomfort, physical disability, psychological disability, and overall score. Within-group comparison showed higher scores for the FA group in comparison to the OA group. Functional limitation scores were higher at T1 than at T0 (p = 0.034), while physical pain scores were higher at T1 compared to T0 (p = 0.034) and T2 (p = 0.010). Psychological discomfort scores were higher at T1 than at T2 (p = 0.015). Physical disability scores were higher at T1 compared to T0 (p = 0.008). Overall scores were higher at T1 than at T2 (p = 0.003). No significant changes were observed in the OA within-group comparison. Patients treated with OAs had less impact on OHRQoL compared to those treated with FAs in the first month. There was no difference between the groups at the 6-month follow-up.

The study objective was to analyze dimensional change, flexural strength, surface hardness, wear profile, and conversion degree of different additive splint materials under various post-polymerization conditions of time and artificial aging. Two additive manufacturing systems (Cara Print 4.0, Dima Print Ortho, Kulzer; SprintRay Pro, SprintRay Splint, SprintRay), and a thermally activated resin control (Clássico) were evaluated in artificial aging (deionized water or saliva; 28 or 84 days at 37°C), with recommended or doubled post-polymerization cycles. Dimensional change (surface metrology), flexural strength (ISO 20795-1:2013), fractography (SEM), Knoop hardness, two-body wear profilometry (150,000 cycles; 3mmØ; 20N; 2.1Hz), and conversion degree (FTIR spectroscopy) were assessed. Two-way ANOVA and post-hoc Tukey tests were used for parametric data, and Kruskal-Wallis and post-hoc Dunn tests, for non-parametric data (α = 0.05). Results indicated no statistically significant differences in dimensional change or flexural strength among the materials. Recommended post-polymerization cycles resulted in lower hardness for additive resins than the thermally activated control. Doubling post-polymerization time significantly increased flexural strength and hardness of Dima Print Ortho, but decreased flexural strength of SprintRay Splint, and did not affect wear resistance. Dima Print Ortho demonstrated the highest wear resistance. Artificial aging did not affect flexural strength, surface wear, or dimensional change, but negatively impacted the hardness of all materials except Dima Print Ortho. The conversion degree was unaffected by post-polymerization time, and no significant differences were found among the materials. Overall, additive materials exhibited mechanical and dimensional properties comparable to thermally activated resin, with doubling post-polymerization time positively influencing the properties.

The aim of this study was to compare the esthetic, functional, and psychosocial impact of mandibular crowding and maxillary midline diastema in black adolescents. A cross-sectional study was conducted with 420 black (brown and black, distinguished according to Brazilian Institute of Geography and Statistics - IBGE) adolescents aged 12 with normal occlusal relationships. Esthetic (OASIS) and functional/psychosocial (OHIP-14) impact related to the need for orthodontic treatment in groups with mandibular crowding and maxillary midline diastema, and those without these conditions: G1, without crowding and diastema (n 113); G2, without crowding and with diastema (n 67); G3, with crowding and without diastema (n 202); and G4, diastema, and crowding (n 38) were evaluated. Generalized linear models were estimated for the effects of diastema, crowding, and the interaction between them, with a significance level of 5%. There was no significant influence of crowding and diastema on the OHIP-14 (p>0.05). However, the groups with diastema had higher OASIS scores, irrespective of crowding (p<0.05). The maxillary midline diastema influenced the esthetic perception of black adolescents.

The objective of this study was to evaluate the occlusion potential of in-office desensitizing agents, and characterize the human dentin elements after acid exposure. Twelve human dentin discs were sectioned into four specimens each, and randomized into treatments (n = 20): no treatment (negative control); no treatment and 6% citric acid exposure (positive control); application of Gluma desensitizer (Heraeus Kulzer) or PRG Barrier Coat (Shofu), followed by 6% citric acid exposure. Occlusion and dentin surface characteristics were determined by scanning electron microscopy (SEM, n = 10), and elemental composition (at%), by energy-dispersive X-ray spectroscopy (EDS, n = 10). Three calibrated, blinded evaluators used SEM to categorize the occlusion potential: 1 = occluded, 2 = partially unoccluded, 3 = equally occluded/unoccluded, 4 = partially occluded, 5 = unoccluded. Data were analyzed by weighted kappa, Friedman, and Nemenyi tests (α = 0.05). For SEM, mean occlusion scores were higher for the PRG Barrier Coat than the positive control (p = 0.0235). Most specimens in the controls scored 4 or 5. The most frequent scores for PRG Barrier Coat were 1(60%) and 2(20%), while 30% of Gluma specimens scored 1 and 2. Gluma showed intratubular precipitation, while PRG Barrier Coat covered dentinal tubules totally or partially. For EDS, the K% was lower for Gluma than the negative control (p = 0.0046), with Si peaks in dentin treated with PRG Barrier Coat. The bioactive in-office desensitizing agent with S-PRG filler (PRG Barrier Coat) promoted dentin tubule occlusion, and persisted after exposure to acid.

An association between bruxism and musculoskeletal disorders, such as neck pain, has been established. This study investigated the association of possible sleep bruxism (PSB) activities, including grinding, bracing, and thrusting, with smartphone use, smartphone-induced neck pain, and sleep features. This cross-sectional study involved 403 Brazilian adolescents aged 11 to 19 years. A self-administered questionnaire was used to assess the severity of PSB, smartphone use, smartphone-induced neck pain, and sleep features (sleep duration and quality and history of nightmares). Sociodemographic factors, as well as snoring and drooling on the pillow, were considered potential confounders and were assessed based on reports from parents/caregivers. Participants were selected using multiple-stage sampling. Descriptive analysis and multinomial regression were performed (p ≤ 0.05). Adolescents reporting nightmares at least once a month (OR = 3.402; 95%CI: 1.315-8.802) and sometimes experiencing smartphone-induced neck pain (OR: 3.697, 95%CI: 1.103-12.388) were more likely to report moderate/severe grinding. Drooling on the pillow (OR = 3.105, 95%CI: 1.316-7.329), poor/fairly good sleep quality (OR = 2.717, 95%CI: 1.279-5.770), and smartphone-induced neck pain (OR = 3.227, 95%CI: 1.121-9.285) were associated with mild bracing. Adolescents experiencing nightmares once a week (OR = 3.209, 95% CI: 1.202- 8.565) had a higher prevalence of mild thrusting. Self-reported smartphone-induced neck pain, nightmares, poor/fairly good sleep quality, and drooling on the pillow were associated with a higher prevalence of PSB activities among Brazilian adolescents. Clinicians and researchers are encouraged to include assessments of smartphone use and sleep features in anamnesis, promoting a comprehensive approach to PSB, from diagnosis to treatment.

The aim of this study was to assess the oral condition of individuals diagnosed with COVID-19 and its impact on their quality of life. The cross-sectional study participants were patients with or without a diagnosis of COVID-19, on room air, and conscious, admitted to the ICUs and wards of Public Hospital Units in São Luís, Maranhão, Brazil. The data collected included: demographic information, length of stay, comorbidities, and type of diet, obtained from medical records; Oral Health-Related Quality of Life (OHRQoL) [Oral Health Impact Profile (OHIP-14)]questions patients were asked; oral health (measured by the Bedside Oral Exam Scale); oral hygiene status (assessed by the Oral Hygiene Index - Simplified and lingual: degree of lingual coating); and salivary flow. The prevalence of COVID-19 was associated with gender (p = 0.038), with a higher incidence observed in male patients (61.9%). Moreover, there was a correlation between the hospitalization sector (p = 0.037) and the frequency of ICU admissions (53.7%). The prevalence of comorbidities was comparable between the two groups. Relative to oral health, 53% of individuals with confirmed COVID-19 had moderate oral health, while 9% exhibited poor oral health. The prevalence of hyposalivation was higher in the group with a confirmed diagnosis of COVID-19. The quality of life of individuals with confirmed COVID-19 was most significantly impacted by moderate to severe oral health concerns. The most significant alteration in oral health was a reduction in salivary flow, negatively impacting the quality of life of individuals hospitalized for COVID-19 complications.

Objectives: Cone beam computed tomography (CBCT) is an imaging exam used increasingly in various fields of dentistry, and a greater number of endodontists are progressively gaining access to this technology. This study focused on applying an artifact suppression algorithm featured in CBCT software, and designed specifically to address artifacts related to root canal filling materials.

Method: The sample consisted of eighty-four mandibular molars, with mesial root canals endodontically treated by using the lateral condensation technique. Four root canal sealers were applied: G1 - Sealapex®, G2 - AH Plus®, G3 - Endofill®, and G4 - Bio-C Sealer. CBCT scans were taken using PreXion 3D Elite®. Initially, the diameter of the root canal filling (in the mesiodistal and buccolingual directions) was measured using a digital micrometer (control). Next, these diameters were reevaluated in the CBCT images using the blooming artifact reduction (BAR) tool of the e-Vol DX software. The Van der Waerden nonparametric analysis of variance was performed, followed by applying the Tukey test to the normalized data. The significance level was set at α = 5%.

Results: There were no statistically significant differences (p>0.05) in the measurement of original root canal filling materials obtained by the micrometer versus the e-Vol DX software in the mesiodistal and buccolingual directions.

Conclusions: The tested software algorithm effectively suppressed artifacts resulting from obturation materials.