Preload and Removal Torque of Two Different Prosthetic Screw Coatings-A Laboratory Study.

This study aimed to evaluate the effect of two coating materials, a silicone sealing gel and a polytetrafluoroethylene (PTFE) tape, on the screw preload and removal torque value (RTV) to develop strategies to prevent prosthetic screw loosening. We examined 45 complexes comprising an implant, abutment, and prosthetic screw, of which 15 samples were uncoated, 15 were coated with GapSeal® (Hager & Werken GmbH & Co., Duisburg, Germany), and 15 were coated with PTFE tape (MIARCO®, Valencia, Spain). The screws were tightened to register the preload and then untightened to register the RTV. The preload values showed a statistically significant difference only in the PTFE group, suggesting that this lubricant negatively affects the preload. The RTVs showed statistically significant differences among all groups, with the GapSeal® group and PTFE group showing the highest and lowest values, respectively. It can be concluded that the application of the PTFE tape on the screw significantly reduced the preload and RTV. The silicone sealing gel did not affect the preload but increased the RTV. Therefore, the use of GapSeal® should be considered to prevent prosthetic screw loosening, while the use of PTFE tape should be avoided.

Osseodensification vs. Conventional Osteotomy: A Case Series with Cone Beam Computed Tomography.

Introduction: Osseodensification is a non-extraction technique using specially designed drills to increase bone density while extending an osteotomy, allowing bone to be preserved and condensed by compacting autograft during osteotomy preparation, increasing bone density around implants, and improving mechanical stability. Aim: The objective of this study is to compare conventional osteotomy and osseodensification protocols in implant placement and analyze whether there are differences in bone density. Materials and Methods: Study variables were defined, namely, osseodensification technique, conventional osteotomy technique, bone density, sex, area of location, implant dimensions, implant dimensions, and implant stability. Eligibility and exclusion criteria were defined. A step-by-step surgical protocol was developed. The surgeon and radiologist underwent intra-examiner calibration. A total of 15 patients were selected according to the eligibility criteria, and a total of 41 implants were inserted, 20 implants by conventional osteotomy and 21 by osseodensification. A cone beam computed tomography was performed one year after prosthetic rehabilitation to estimate bone density. Data were collected and recorded, and in the analysis of the association of variables, non-parametric tests were applied. Results: Significant statistical results were found in bone density values, with higher values being obtained with the osseodensification technique, that is, median density values of 1020, and median density values of 732 for the bone drilling technique. The results of the correlation between bone density in both techniques and sex, primary implant stability, implant dimensions and location area were statistically non-significant. Conclusions: Within the limitations of this study, there are differences in bone density between conventional osteotomy and osseodensification protocols. Bone density is increased with osseodensification over a study period of one year.

SEM Analysis and Micro-CT Evaluation of Four Dental Implants after Three Different Mechanical Requests-In Vitro Study.

STATEMENT OF PROBLEM: Implant-supported rehabilitations are an increasingly frequent practice to replace lost teeth. Before clinical application, all implant components should demonstrate suitable durability in laboratory studies, through fatigue tests. OBJECTIVE: The purpose of this in vitro study was to evaluate the integrity and wear of implant components using SEM, and to assess the axial displacement of the implant-abutment assembly by Micro-CT, in different implant connections, after three distinct mechanical requests. MATERIALS AND METHODS: Four KLOCKNER implants (external connection SK2 and KL; and internal connection VEGA and ESSENTIAL) were submitted to three different mechanical requests: single tightening, multiple tightening, and multiple tightening and cyclic loading (500 N × 100 cycles). A total of 16 samples were evaluated by SEM, by the X-ray Bragg-Brentano method to obtain residual stresses, and scratch tests were realized for each surface and Micro-CT (4 control samples; 4 single tightening; 4 multiple tightening; 4 multiple tightening and cyclic loading). All dental implants were fabricated with commercially pure titanium (grade 3 titanium). Surface topography and axial displacement of abutment into the implant, from each group, were evaluated by SEM and Micro-CT. RESULTS: In the manufacturing state, implants and abutments revealed minor structural changes and minimal damage from the machining process. The application of the tightening torque and loading was decisive in the appearance and increase in contact marks on the faces of the hexagon of the abutment and the implant. Vega has the maximum compressive residual stress and, as a consequence, higher scratch force. The abutment-implant distances in SK2 and KL samples did not show statistically significant differences, for any of the mechanical demands analyzed. In contrast, statistically significant differences were observed in abutment-implant distance in the internal connection implants Vega and Essential. CONCLUSIONS: The application of mechanical compression loads caused deformation and contact marks in all models tested. Only internal connection implants revealed an axial displacement of the abutment into the implant, but at a general level, a clear intrusion of the abutment into the implant could only be confirmed in the Essential model, which obtained its maximal axial displacement with cyclic loading.

Osseodensification: An Alternative to Conventional Osteotomy in Implant Site Preparation: A Systematic Review.

Osseodensification is an innovative method of preparing the implant osteotomy using drills that promote bone self-compaction. The main objective of this technique is to promote peri-implant bone densification and compaction of autologous bone and to increase the primary stability of the implant due to the viscoelastic characteristics of the alveolar bone using Densah® burs in a counterclockwise direction at a speed of 800 to 1500 rpm. The objective of this review is the analysis of the scientific literature regarding the applicability of the osseodensification technique in oral implantology. The Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines were used and registered at PROSPERO. The search strategy included electronic databases from 2016 to 2023 and was performed by two independent reviewers. The results demonstrate the advantage of the osseodensification technique in relation to conventional drilling, allowing an increase in the bone density and primary stability of the implant, bone density, and bone-implant contact. The osseodensification technique can be applied in different clinical situations: sub-antral bone grafts, narrow alveolar bone crests, low-density bone areas, and immediate implant placement in post-extraction sockets.

Influence of Popular Beverages on the Fracture Resistance of Implant-Supported Bis-Acrylic Resin Provisional Crowns: An In Vitro Study.

Implant-supported provisional restorations are critical for improving the esthetics and shaping of the peri-implant tissue. The mechanical properties of these provisional materials can be influenced by saliva, food, beverages, and interactions between these materials in the oral environment. Therefore, the integrity of provisional restorations should be preserved throughout the treatment period. This study aimed to evaluate the fracture strength of implant-supported polymethyl methacrylate (PMMA) provisional restorations made of computer-aided design and computer-aided manufacturing when immersed in different solutions at a controlled temperature of 37 °C for 7 days. Each analog-pillar-crown set was submerged in different liquids: 10 pieces were placed in distilled water then in tea, coffee, red wine, and Coca Cola® for 1 week at a controlled oral temperature of 37 °C. The samples were then subjected to fracture forces. The moment of fracture of the crown was recorded and compared with those of the other samples. Specimens immersed in distilled water (control group) had the highest fracture resistance (mean [M] = 1331.00 ± 296.74 N), while those immersed in tea had the lowest mean resistance to fracture (mean [M] = 967.00 ± 281.86 N). Nutritional deficiency and inappropriate eating habits influence the fracture strength of temporary crowns, thereby rendering them more elastic or less resistant to fractures.

The Influence of Cleaning Solutions on the Retention of Overdenture Attachment Systems.

Dental-implant-supported reconstructions provide comfort and improvements in prosthetic function, adaptation, and stability over conventional treatment options. The objective of this study was to evaluate the effect of different denture cleansing solutions and their influence on the deterioration and loss of retention of overdenture attachments in a 12-month clinical-use simulation. In this way, ten specimens each of different brands of retentive caps made of Teflon (OT Equator® (Rhein83, Bologna, Italy), Locator® (Zest Anchors, Escondido, CA, USA), Kerator® (KJ Meditech, Gwangiu, Republic of Korea), and Locator R-Tx® (Zest Anchors, Escondido, CA, USA)) were immersed in five different cleaning solutions (Kukident® (P&G Tech, Oxford Parkway, UK), Benfix® (Laboratorios URGO S.L., Guipúzcoa, Spain), Corega® (Stafford Miller, Waterford, Ireland), and Protefix® (Neuhofer Weiche, Parchim, Germany)), and tap water was used as the control group, in a simulation that lasted 12 months. Data were analyzed using two-way ANOVA and a Tukey HSD. Furthermore, a Levene Test and Shapiro-Wilk tests were performed to assess the validation of the ANOVA assumptions. The statistical analysis was performed using R version 4.2.2 software with the significance level set to p < 0.05. There were significant statistical differences between the different manufacturers regarding the retention forces of the attachment's retentive caps (F = 322.066, p < 0.001). For the cleaning solution groups, different statistical results between Kukident® (P&G Tech, Oxford Parkway, UK) (p < 0.05) and Benfix® (Laboratorios URGO S.L., Guipúzcoa, Spain) (p < 0.05) were observed. There were no significant statistical differences between Corega® (Stafford Miller, Ireland), Protefix® (Neuhofer Weiche, Parchim, Germany), and tap water, even though the retention forces decreased in all of them.

The Influence of Saliva pH on the Fracture Resistance of Two Types of Implant-Supported Bis-Acrylic Resin Provisional Crowns-An In Vitro Study.

Temporary restorations play a fundamental role in oral rehabilitation. A properly adapted implant-supported provisional restoration implies better esthetics, contouring and architectural modeling of the upper peri-implant tissue. This study aimed to evaluate the influence of oral pH on the fracture resistance of implant-supported provisional restorations made with two brands of bis-acrylic resin (LuxaCrown® and Protemp™ 4) and to compare the fracture resistance of these two materials. Twenty crowns (ten manufactured using each brand) served as a control, and another forty crowns (twenty of each brand) were aged using artificial saliva with pHs of 4 or 7, for 7 days at 37 °C, in an attempt to simulate the behavior of these materials inside the oral cavity. Subsequently, all crowns were subjected to the application of a force at a constant speed, in a universal testing machine, until fracture was achieved. The LuxaCrown® brand showed greater resistance to fracture than the Protemp™ 4 brand. Salivary pH did not influence the fracture resistance of provisional LuxaCrown® crowns but did influence the fracture resistance of provisional Protemp™ 4 crowns.

Fracture Resistance of CAD/CAM Implant-Supported 3Y-TZP-Zirconia Cantilevers: An In Vitro Study.

(1) Introduction: Implant-supported fixed complete dentures are mostly composed of cantilevers. The purpose of this work was to evaluate the fracture resistance of zirconia (Prettau®, second generation, or Ice Zirkon Translucent, first generation) with cantilever lengths of 6 and 10 mm, and zirconia's fracture resistance in relation to an average bite force of 250 N. (2) Materials and methods: Forty structures were created in CAD/CAM and divided into four groups: group A (6 mm cantilever in IZT), group B (10 mm cantilever in IZT), group C (6 mm cantilever in Pz), and group D (10 mm cantilever in pz). The study consisted of a traditional "load-to-failure" test. (3) Results: A statistically significant result was found for the effect of cantilever length, t(38) = 16.23 (p < 0.001), with this having a large effect size, d = 4.68. The 6 mm cantilever length (M = 442.30, sd = 47.49) was associated with a higher mean force at break than the 10 mm length (M = 215.18, sd = 40.74). No significant effect was found for the type of zirconia: t(38) = 0.31 (p = 0.757), and d = 0.10. (4) Conclusions: All the components with cantilever lengths of 6 mm broke under forces higher than 250 N. Cantilevers larger than 10 mm should be avoided.

In Vitro Comparison of Three Intraoral Scanners for Implant-Supported Dental Prostheses.

With continuing technological developments, there have been advances in the field of fixed prosthetics, particularly in impression-taking techniques. These technological advances mean that a wide variety of diagnostic and/or rehabilitation possibilities can be explored without the need for physical models. The aim of this study was to evaluate the accuracy of three intraoral scanners used in oral implant rehabilitation using an extraoral scanner as a reference and varying the scanning area. Three models representing different clinical scenarios were scanned 15 times by each intraoral scanner and three times by the extraoral scanner. The readings were analyzed and overlaid using engineering software (Geomagic® Control X software (Artec Europe, Luxembourg)). Statistically significant differences in accuracy were found between the three intraoral scanners, iTero® (Align Technology Inc., San Jose, CA, USA), Medit® (Medit®: Seoul, Korea), and Planmeca® (Planmeca®: Helsinki, Finland). In all clinical scenarios, the iTero® scanner had the best trueness (24.4 µm), followed by the Medit® (26.4 µm) and Planmeca® (42.1 µm). The Medit® showed the best precision (18.00 µm) followed by the iTero® (19.20 µm) and Planmeca® (34.30 µm). We concluded that the iTero® scanner had the highest reproducibility and accuracy in the clinical setting.

Retention Capacity of Original Denture Adhesives and White Brands for Conventional Complete Dentures: An In Vitro Study.

(1) Introduction: Denture adhesives (DAs) promote stability, chewing ability, and quality of life. The objective of this study was to compare the effectiveness of original brand DAs and white brands in their retention of conventional complete dentures. (2) Methods: This study followed the recommendations of the international standard ISO 10873. Three original brands of DA (Corega® Fixação 3D, GlaxoSmithKline®, Stafford Miller Ltd., Dungarvan Co. Waterford, Ireland), KuKident® Pro Procter & Gamble Technical Centres®, Ltd., Whitehal Lane, Germany and Elgydium® Fix, Laboratórios URGO® SL, Florida, Spain) were compared to three white brands (Fixação Extra Forte Pingo Doce®, Laboratórios Cosmodent®, Cantabria, Spain), Fixador de Próteses (Continente®, Propack®,Gmbh, Ladenburg, Germany) and Creme Fixador de Próteses (Auchan®, Ellipse®, Roubaix, France). Their retention capacities were analyzed using a mechanical test device. (3) Results: The mean retentive ability of original brand adhesives (M = 11.16, SD = 5.27) was significantly higher (t(298) = 11.88; p < 0.001) than that of the white brands (M = 5.92, SD = 1.18). When comparing all brands, statistically significant differences were also observed, F(5.294) = 707.68 (p < 0.001). The generic adhesive results were more homogeneous. The generic brands from Continente® (M = 5.24, SD = 0.94) and Auchan® (M = 5.80, SD = 0.79) were not significantly different, while the Pingo Doce® brand obtained significantly higher mean retention results (M = 6.71, SD = 1.28). (4) Conclusions: The original brands of DA have a significantly higher retentive ability than the white brands. Elygidim® Fix had the worst result of the three original brands, and the product from Pingo Doce® had the best result among the three white brands.

Comparison of Mechanical Resistance to Maximal Torsion Stress in Original and Nonoriginal or Compatible Prosthetic Implant Screws: An In Vitro Study.

Micromovements of the implant-abutment connection influence peri-implant bone preservation. The maximal torque after a cycle of implant prosthetic screw tightening using original components of different manufacturers and replicas produced by other companies is evaluated and quantified in this study. A total of 30 Mis Seven® standard platform implants and 30 interfaces were used, and 30 standard platform screws were tested, 10 Mis®, 10 Iconekt®, and 10 Exaktus®. The screws were tightened with an MIS® torquemeter until their respective fracture, and the fracture point was measured through the equipment's load cell, CS-Dental Testing Machine®. The screws were analyzed under an Olympus® SZ61 microscope. The fracture points were recorded and compared among all samples. To compare the mean values of the fracture torques, t-tests were performed using the reference values associated with each brand and the sample results. The variable "Place of Fracture" between the original Mis® brand and the Exaktus® replica compared to the Iconekt® replica presented a statistically significant difference (p < 0.001). When analyzing the variable "Fracture Torque," although it was verified that the replica screws (Iconekt® and Exaktus®) had a lower maximum torque, 65.11 Nm and 62.89 Nm, respectively, compared to the original Mis® brand (70 Nm and 69 Nm), there were no statistically significant differences p > 0.05. Nonoriginal screws did not present different fracture resistances compared to the original Mis® brand screws. The fracture site of Iconekt® screws showed a different pattern compared to the other brands.

The Effect of Different Dietary and Therapeutic Solutions on the Color Stability of Resin-Matrix Composites Used in Dentistry: An In Vitro Study.

The purpose of this study was to evaluate the color stability of aesthetic restorative resin-matrix materials after their immersion in different dietary and therapeutic solutions. Thirty disc-shaped specimens (10 × 2 mm) were prepared from three different types of resin-matrix composites used in dentistry (BE, FS, AF). The color coordinates (L*a*b*, ΔL*, Δa*, Δa*, Δb* and ΔE*) were measured using a VITA Easyshade 3D-Master (VITA Zahnfabrik, Bad Säckingen, Germany) before and after the immersion of the specimens in coffee, red wine, Coca-Cola®, Eludril Care®, and distilled water solutions for 40 h. The color change (ΔE*) was calculated and analyzed by the Kolmogorov -Smirnov test and the Kruskal -Wallis multiple-comparison test. All the restorative materials showed significant color (ΔE*) changes after their exposure to red wine, followed by coffee and Coca-Cola®; however, one nanohybrid resin-matrix composite showed a high color stability in such colored test solutions. The chemical composition and content of the organic matrix played a key role in the color stability of the resin-matrix composites. Clinicians should advise their patients about the chemical interaction between dietary substances and different resin-matrix composites.

Survival Rates of Anterior-Region Resin-Bonded Fixed Dental Prostheses: An Integrative Review.

This study aimed to review clinical publications involving anterior-region resin-bonded fixed partial dentures to evaluate their survival rates vis-à-vis their materials and design. An electronic search was conducted using PubMed/MEDLINE to identify articles that reported on the longevity of anterior resin-bonded fixed dental prostheses published between 2000 and 2020. Only primary clinical studies that involved a follow-up after at least 3 years were included in this review. A statistical analysis was performed to evaluate resin-bonded fixed dental prostheses' survival rates in relation to their materials and design. This review ultimately included 23 clinical publications, comprising prospective studies, retrospective studies, and randomized controlled trials. Its statistical analysis estimated the studied prostheses' 5-year survival rate at 86.2% for metal-framed prostheses, 87.9% for zirconia prostheses, 93.3% for alumina prostheses, 100% for glass or ceramic prostheses, and 81.7% for fiber-reinforced composite restorations. Failure rates did not significantly differ between the different material groups or between the single- and double-retainer groups. Resin-bonded fixed dental prostheses present excellent 5-year clinical longevity in the anterior sector and a favorable benefit/risk/cost ratio. Currently, no consensus has been established on an ideal material for these restorations. Cantilever design tends to limit constraints on the prostheses' retainers and, thus, increases their survival time. All-ceramic cantilever fixed partial dentures can be considered as a definitive therapy, given their high success and survival rates. They are an optimal solution for adolescents or young adults facing potentially continuous growth.

Environment Actors Confronting a Post Climate-Related Disaster Scenario: A Feasibility Study of an Action-Based Intervention Aiming to Promote Climate Action.

(1) A climate change awareness-action gap still prevails in our society, with individuals showing significant social inertia regarding environmental issues. The communication on climate change is pointed out as one of the causes of the social inertia; (2) Following an action-oriented transformation research, the main goal of this study was to ascertain the feasibility of an action-based communication intervention, based on the participants' exposure to a post climate-related disaster scenario. The feasibility of the action-based communication intervention was assessed in a focus group meeting, whose content was qualitatively analysed; (3) The results of this study demonstrate that action-based communication interventions are feasible to trigger an attitude transformation, catalysed by the experiential processing of climate change and by the affect arousal; (4) This study comes to contribute to a transformation of the climate change communication praxis, by highlighting the urgency to shift the for a new paradigm of communicating climate change, in which the affect and the experiential processing should account for conveying environment-related information in order to promote society's climate action.

Comparison of Fracture Resistance in Thermal and Self-Curing Acrylic Resins-An In Vitro Study.

Thermal and self-curing acrylic resins are frequently and versatilely used in dental medicine since they are biocompatible, have no flavor or odor, have satisfactory thermal qualities and polishing capacity, and are easy and fast. Thus, given their widespread use, their fracture resistance behavior is especially important. In this research work, we comparatively analyzed the fracture resistance capacity of thermo and self-curing acrylic resins in vitro. Materials and Methods: Five prosthesis bases were created for each of the following acrylic resins: Lucitone®, ProBase®, and Megacryl®, which were submitted to different forces through the use of the CS® Dental Testing Machine, usually mobilized in the context of fatigue tests. To this end, a point was defined in the center of the anterior edge of the aforementioned acrylic resin bases, for which the peak tended until a fracture occurred. Thermosetting resins were, on average, more resistant to fracture than self-curable resins, although the difference was not statistically significant. The thermosetting resins of the Lucitone® and Probase® brands demonstrated behavior that was more resistant to fracture than the self-curing homologues, although the difference was not statistically significant. Thermosetting resins tended to be, on average, more resistant to fracture and exhibited the maximum values for impact strength, compressive strength, tensile strength, hardness, and dimensional accuracy than self-curing resins, regardless of brand.

Clinical evaluation of the implant survival rate in patients subjected to immediate implant loading protocols.

BACKGROUND: In the past 20 years, several studies and clinical trials have reported similar results for transmucosal implants as compared to submerged implants. Several advantages of immediate loading have been pointed out, such as the reduction of treatment time, trauma reduction, and immediate esthetic and functional improvements. OBJECTIVES: The main objective of this study was to clinically evaluate the implant survival rate in patients with total rehabilitation via implants that underwent immediate loading in the past 5 years. MATERIAL AND METHODS: A cross-sectional, descriptive, observational analysis was conducted. The implant survival rate for an edentulous maxilla or mandible was assessed with regard to the loading protocol by means of a questionnaire and clinical observation. The study included 103 patients with edentulous jaws rehabilitated with fixed prostheses on implants. Each patient received 4-6 implants. In total, 474 implants were placed. Factors such as the implant survival rate as well as biological and prosthetic complications were evaluated and analyzed statistically. RESULTS: Of the 474 implants initially placed, 458 were considered osteointegrated and 16 were considered lost, which corresponds to a 96.62% implant survival rate. The most common types of failure were prosthetic fractures (46.2%), peri-implantitis (23.1%) and unscrewing (11.5%) in the first 5 years. CONCLUSIONS: The rate of osseointegration for implants placed under immediate loading was extremely high, in accordance with the previously published studies, which led us to conclude that currently, this is a surgical procedure with a high rate of success and high predictability.

The Influence of Saliva pH on the Fracture Resistance of Three Complete Denture Base Acrylic Resins.

METHODS: Ten prosthesis bases prepared with each brand of resin were subjected to neutral and low pH conditions (pH 7 and pH 4) by submerging them in artificial saliva for 30 days. After exposure, the fatigue resistance of the resins was tested using a Dental CS® Testing Machine. Statistical Analysis Test. The data sets were described quantitatively in terms of mean (M) and standard deviation (SD). Shapiro-Wilk tests and unilateral analysis of variance (ANOVA) were performed and complemented by Tukey's multiple comparison tests. The effect size (η2), whose cohort points followed Cohen's recommendations: 0.01 (low), 0.06 (medium), and 0.14 (high), was calculated. The results were considered significant if p < 0.05 and marginally significant if p < 0.10. RESULTS: One-way ANOVA showed that Megacryl® had the highest fracture resistance at pH 7 (52.23 Kgf), compared with Triplex Hot® (p < 0.001) and RS Vertex® (p=0.034). Two-way ANOVA confirmed the interaction between brand and pH (p=0.022), also revealing that brands comparison is significant or marginally significant, when pH is not considered (Megacryl® versus Triplex Hot®, p < 0.001, and RS Vertex®, p=0.058; Triplex Hot® versus RS Vertex®, p=0.051), and pH 7 results were significantly higher (p=0.003), even when brands are not considered. Hence, Megacryl® at pH 7 was found to have the highest fracture resistance, detached from other brands and pH values. CONCLUSION: It can be concluded within the limitations of this study that there are differences in the fracture resistance among the three brands of acrylic resin. Megacryl® was found to have the highest fracture resistance, and Triplex Hot® was the lowest. The results also show that exposure to a low pH environment decreases the fracture resistance of the Megacryl® and RS Vertex® resins.

The role of media between expert and lay knowledge: A study of Iberian media coverage on climate change.

Individuals play a crucial role in combating climate change, but high levels of acknowledgment and engagement are needed to lead to changes toward more sustainable behaviours. In this aspect, media plays an important role in shaping individuals' awareness about climate change. This study aims to analyse Iberian media coverage about climate change to further discuss its influence on the public's engagement with the subject. A total of 449 news were collected from Iberian newspapers. Their characteristics were analysed through quantitative content analysis. Data shows important journalistic bias toward a national framing, mainly focusing on drought and its impact on agriculture. The debate is focused on technological and political discourses. The gaps found on the Iberian media coverage may contribute to public's low levels of acknowledgement and engagement, not enhancing the possibility of change in individuals' behaviours for more sustainable actions.

Multicenter study of patients' preferences and concerns regarding the origin of bone grafts utilized in dentistry.

PURPOSE: Bone graft materials can be obtained from the patient's own body (autologous graft), animals (xenograft), human cadavers (allograft) and synthetic materials (alloplastic bone graft). Patients may have ethical, religious or medical concerns about the origin of bone grafts, which could lead them to reject the use of certain types of bone graft in their treatments. The aim of this multicenter study, which surveyed patients from five university clinics in Portugal, France, Italy, Spain and Chile, was to analyze patients' opinions regarding the source of bone grafts. PATIENTS AND METHODS: A survey composed of ten questions was translated into local languages and validated. Patients were asked about the degree of acceptance/rejection of each graft and the reasons for rejection. A chi-squared test was used to analyze statistically significant differences. RESULTS: Three hundred thirty patients were surveyed. The grafts that elicited the highest percentage of refusal were allograft (40.4%), autologous bone graft from an extraoral donor site (34%) and xenograft (32.7%). The grafts with the lowest rate of refusal were alloplastic (6.3%) and autologous bone grafts from an intraoral donor site (24.5%). The main reason for autologous bone rejection was the fear of pain and discomfort, for xenograft it was the fear of disease transmission and the rejection of use of animals for human benefit, and for allograft it was ethical/moral motivations and the fear of disease transmission. Religious affiliation influenced patient's preferences. CONCLUSION: The origin of bone grafts is still conflictive for a high percentage of patients.

Implicações bioéticas para o licenciamento ambiental de grandes empreendimentos no Brasil / Bioethical implications in the environmental licensing of large enterprises in Brazil

Resumo O processo de licenciamento ambiental de refinarias de petróleo no Brasil tem sido criticado pela ausência do cuidado com relação aos efeitos decorrentes do empreendimento sobre a saúde. Por isso, este trabalho busca identificar ferramentas da bioética que contribuam para a proteção da saúde nesse processo. Amparado numa revisão integrativa da literatura científica e no método desconstrutivo proposto por Derrida, justifica-se a pertinência e legitimidade do uso da bioética para fundamentar a relação entre as consequências para a saúde dos indivíduos, populações e dos ecossistemas e a conflituosidade envolvida. Conclui-se que a bioética pode contribuir como ferramenta teórica e prática por meio da descrição, avaliação dos conflitos e dilemas morais envolvendo a licença para implantação de processos produtivos, servindo para processos de crítica, justificação e de estabelecimento de medidas moralmente aceitáveis para a proteção da saúde humana e dos demais seres vivos do ecossistema.

Abstract Brazilian oil refineries' environmental licensing process have been criticised for lack of healthcare aspects. Therefore, this paper aims to identify elements of bioethics that contribute to healthcare in this process. Based on an integrative review of scientific literature and on the deconstructive method proposed by Derrida, the relevance and legitimacy of bioethics to justify the relationship between morality and the consequences for individual's, populations's and ecosystems's health is justified. We conclude that bioethics may contribute as a theoretical and practical tool to solve conflicts by describing existing struggles and moral dilemmas, through processes of criticism and justification and the establishment of morally acceptable measures for the protection of humans and environmental health.