Renata de Castro Martins

Flexibility and Torsional Strength of ProTaper and ProTaper Universal Rotary Instruments Assessed by Mechanical Tests

The purpose of this study was to assess how the geometric and dimensional changes made on ProTaper Universal (PTU) instruments in comparison with ProTaper (PT) instruments affected their flexibility and torsional strength. Two groups (n = 12) of each type of shaping (S1 and S2) and finishing (F1, F2, and F3) for both PT and PTU instruments were employed. Tip angle, instrument diameter at each millimeter, and cross-sectional area at 3 mm from the tip were the dimensional parameters measured. Flexibility and torsional strength of each instrument (n = 12) were assessed according to specification ISO 3630-1. Data were analyzed using analysis of variance (alpha = 0.05). Flexibility increased for S1 and F1 PTU instruments and decreased for F2 and F3, whereas torsional resistance increased for S2, F2, and F3. Changes in tip angle were accompanied by variation of tip geometry in all instruments.

Assessment of the cytotoxicity of a mineral trioxide aggregate-based sealer with respect to macrophage activity.

AIM To assess the influence of co-culture with mineral trioxide aggregate (MTA) and MTA Fillapex (FLPX) on the viability, adherence, and phagocytosis activity of peritoneal macrophages from two mouse strains. METHODOLOGY Cellular viability, adherence, and phagocytosis of Saccharomyces boulardii were assayed in the presence of capillaries containing MTA and MTA Fillapex. The data were analyzed using parametric (Students t) and non-parametric (Mann-Whitney) tests. RESULTS FLPX was severely cytotoxic and decreased cell viability, adherence, and phagocytic activity of both macrophage subtypes. Cells that were treated with MTA Fillapex remained viable (>80%) for only 4 h after stimulation. Macrophages from C57BL/6 mice presented higher adherence and higher phagocytic activity compared with macrophages from BALB/c mice. CONCLUSION Comparison of MTA and FLPX effects upon macrophages indicates that FLPX may impair macrophage activity and viability, while MTA seems to increase phagocytic activity.

Relationship between Primary and Secondary Dental Care in Public Health Services in Brazil

This cross-sectional study evaluated the relationship between primary and secondary oral health care in Brazil. For this purpose, data from the National Program for Improving Access and Quality of Primary Care were used. Dentists from 12,403 oral health teams (OHTs) answered a structured questionnaire in 2012. The data were analyzed descriptively and by cluster analysis. Of the 12,387 (99.9%) OHTs that answered all the questions, 62.2% reported the existence of Dental Specialties Centers (DSCs) to which they could refer patients. The specialties with the highest frequencies were endodontics (68.4%), minor oral surgery (65.8%), periodontics (63.0%), radiology (46.8%), oral medicine (40.2%), orthodontics (20.5%) and implantology (6.2%). In all percentiles, the shortest wait time for secondary care was for radiology, followed by oral medicine and the other specialties. In the 50th percentile, the wait for endodontics, periodontics, minor oral surgery and orthodontics was 30 days, while for implantology, the wait was 60 days. Finally, in the 75th percentile, the wait for endodontics, orthodontics and implantology was 90 days or more. Two clusters, with different frequencies of OHT access to specialties, were identified. Cluster 1 (n = 7,913) included the OHTs with lower frequencies in all specialties except orthodontics and implantology compared with Cluster 2 (n = 4,474). Of the Brazilian regions, the South and Southeast regions had the highest frequencies for Cluster 2, with better rates for the relationship between primary and secondary care. This study suggests certain difficulties in the relationship between primary and secondary care in specific specialties in oral health, with a great number of OHTs with limited access to DSCs, in addition to different performance in terms of OHT access to DSCs across Brazilian regions.

The effects of a mineral trioxide aggregate-based sealer on the production of reactive oxygen species, nitrogen species and cytokines by two macrophage subtypes.

AIM To test the effects of a mineral trioxide aggregate-based sealer (MTA Fillapex(®)) and MTA (MTA-Ângelus(®)) on viability and on the production of cytokines, reactive oxygen species (ROS) and nitrogen species (NO) by M1 and M2 inflammatory macrophages. METHODOLOGY M1 (from C57BL/6 mice) and M2 (from BALB/c mice) peritoneal inflammatory macrophages were obtained and cultured in vitro in the presence of original and diluted extracts of MTA and MTA Fillapex (FLPX). The cell viability, ROS release and the release of tumour necrosis factor-a, interleukin (IL)-12, IL-10 and NO in response to stimulation with interferon-γ and Fusobacterium nucleatum or Peptostreptococcus anaerobius were evaluated. The data were analysed using the Mann-Whitney test and Students t-test. RESULTS Fillapex was cytotoxic at the highest concentrations (1:1;1:2) and decreased the viability (P < 0.05) of both macrophage types (<20%). MTA did not interfere with cellular viability. FLPX inhibited the release of ROS and decreased NO release in F. nucleatum and P. anaerobius -stimulated M1 and M2 macrophages (≤25 μ mol L(-1)). F. nucleatum-stimulated M2 macrophage cultures released lower levels of TNF-α when FLPX was added (≤1 ng mL(-1)). M2 macrophages released higher (>5 ng mL(-1)) levels of IL-10 than M1 macrophages. Only M1 macrophage cultures produced IL-12p70. CONCLUSIONS Fillapex impaired effector immune responses during inflammation (M1 macrophages), as well as during healing (M2 macrophages) responses.

Geometric and dimensional characteristics of simulated curved canals prepared with proTaper instruments

Objective This study identified which regions of ProTaper instruments work during curved root canal instrumentation. Material and methods Twelve ProTaper instruments of each type, S1, S2, F1, and F2, were assessed morphometrically by measuring tip angle, tip length, tip diameter, length of each pitch along the cutting blades, and instrument diameter at each millimeter from the tip. Curved canals in resin blocks were explored with manual stainless steel files and prepared with ProTaper instruments until the apical end following four distinct sequences of instrumentation: S1; S1 and S2; S1, S2, and F1; S1, S2, F1, and F2. Image analysis was employed for measuring canal diameters. The diameters of the canals and diameters of the instruments were compared. Data were analyzed by one-way ANOVA and Tukey’s test. Results No statistically significant difference was found between the canals and instrument diameters (p>0.05). The largest diameters in the end-point of the instrumented canals were obtained with F1 and F2 instruments and in the initial and middle thirds with S1 and S2 instruments. Conclusions All instruments worked at the tip and along their cutting blades, being susceptible to fail by torsion, fatigue, or the combination of these two mechanisms.

Patients’ Perceptions of Endodontic Treatment as Part of Public Health Services: A Qualitative Study

Evaluations by patients constitute an important part of the process of improving health services. This study examined patients’ perceptions of secondary dental care in three cities in Minas Gerais, Brazil based on the endodontic treatment received. Data were collected using semi-structured interviews (addressing access, treatment and results) and a field diary (direct observations and report of professionals). The interviews were audiotaped, fully transcribed, and analyzed using content analysis. Two principal themes were identified: access to service and quality of service. The difficulties in accessing service were associated with the insufficient number of professionals to meet the high demand for endodontic treatment, problems in referring from primary to secondary care and geographic barriers. Service quality was related to the presence/absence of pain and anxiety that patients experienced, the time and number of sessions required to complete treatment, how patients were treated by dentists, and whether those patients would recommend the service to other patients. Access to endodontic treatment was a problem emphasized by users, and satisfaction with the quality of the service was more related to how patients were treated than to the technical competence of the dentist.

Current Evidence About Relationships Among Prosthodontic Planning and Temporomandibular Disorders and/or Bruxism

ARTICLE TITLE AND BIBLIOGRAPHIC INFORMATION Prosthodontic planning in patients with temporomandibular disorders and/or bruxism: A systematic review. Manfredini D, Poggio CE. J Prosthet Dent. 2017;117(5):606‐13. SOURCE OF FUNDING Information not available. TYPE OF STUDY/DESIGN Review.

Evidence-Based Support for Sleep Bruxism Treatment Other Than Oral Appliances Remains Insufficient

ARTICLE TITLE AND BIBLIOGRAPHIC INFORMATION Management of sleep bruxism in adults: A qualitative systematic literature review. Manfredini D, Ahlberg J, Winocur E, Lobbezoo F. J Oral Rehab 2015;42:862–74. SOURCE OF FUNDING The authors declare that they did not receive any financial support for this article TYPE OF STUDY/DESIGN Systematic review

Dental Procedures in Primary Health Care of the Brazilian National Health System

The aim of this study was to examine the procedures of primary dental health care performed by oral health teams (OHTs) adhering to the second cycle of the ‘National Programme for Improving Access and Quality of Primary Care’ (PMAQ-AB) in Brazil. A cross-sectional descriptive analysis was performed, across 23 dental procedures comprising preventive, restorative/prosthetic, surgical, endodontic and oral cancer monitoring. Descriptive analysis shows that most of the oral health teams carry out basic dental procedures. However, most of the time, they do not keep adequate records of suspected cases of oral cancer, diagnosis tests or follow-ups, and do not perform dental prosthetic procedures. Data also showed disparities in the average number of procedures performed in each Brazilian geographical region in 2013–2014, ranging from 13.9 in the northern to 16.5 in the southern and south-eastern regions, reinforcing the great social disparities between them. Brazilian regions with the highest volume of dental need deliver the lowest number of dental procedures. The need to tackle inequalities and further shape the supply of appropriate primary health care (PHC) is evident.

The influence of cyclic straining in torsion on fatigue resistance and torsional properties of ProTaper NiTi endodontic instruments

This study evaluated the influence of cyclic straining in torsion on fatigue resistance and torsional properties of ProTaper (S1, S2, F1, F2, F3) NiTi instruments. The mechanical behavior was evaluated by means of torsion and bending tests, performed according to ISO 3630-1 specification, while the fatigue resistance was evaluated using a bench test device employing an artificial canal with 5mm curvature radius and angle of curvature of 45º. The dimensional aspects, diameter (D3) and cross-sectional area (A3) at 3mm from the tip of the instruments were determined by means of image analysis of optical and scanning electron microscopy (SEM). The surface characteristics of instruments before and after they were submitted to cyclic straining in torsion and the morphological aspects of the fractured surfaces were analyzed by SEM. The maximum torque and the bending moment at 45º were higher for instruments with larger D3 and A3. The F1 and F2 instruments followed the Coffin-Manson’s relation, i.e., their number of cycles to failure (NCF) varied inversely with the strain amplitude. With the exception of S1 and S2 instruments, there was a tendency of decreasing the maximum torque after the instruments have been submitted to cyclic straining in torsion. With the exception of S1 instruments, there was a tendency of decreasing the NCF after torsional cycling. The analyses by SEM showed the presence of longitudinal cracks on the instruments previously cycled in torsion. The morphological aspects of the fractured surfaces of instruments tested in torsion or flexural fatigue did not changed by the cyclic straining in torsion. These changes in mechanical properties with torsional cycling can be related to the generation of imperfections such as longitudinal cracks on the instruments.