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Single tooth orange discoloration secondary to root canal calcification occurs as a consequence of dental trauma, orthodontic treatment, or for unknown rea- sons. A correct case history must be compiled and a CBCT study carried out in order to establish the diag- nosis and define the best treatment plan in each case. The aim of the present study was to offer a therapeutic protocol involving a clinical decision-making tree dia- gram based on the presence or absence of apical dis- ease and the degree of canal calcification. Dental bleaching and the use of ceramic veneers allow es- thetic restoration in such cases.
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Tomografia Computadorizada de Feixe Cônico , Clareamento Dental , Descoloração de Dente , Humanos , Tomografia Computadorizada de Feixe Cônico/métodos , Calcificações da Polpa Dentária/diagnóstico por imagem , Calcificações da Polpa Dentária/etiologia , Facetas Dentárias , Clareamento Dental/métodos , Descoloração de Dente/etiologia , Descoloração de Dente/terapiaRESUMO
The digital workflow for designing and fabricating a magnetically retained and stackable additively manufactured implant surgical guide is described. The technique should improve the stability of the stackable surgical guide and the accuracy of implant placement.
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Implantes Dentários , Desenho Assistido por Computador , Prótese Dentária Fixada por Implante/métodos , Fluxo de TrabalhoRESUMO
OBJECTIVE: The main objective of this study aimed to evaluate the response to treatment in implants with peri-implantitis regarding the presence or absence of keratinized mucosa. MATERIALS AND METHODS: One hundred implants with peri-implantitis were treated non-surgically at the Prosthodontics and Occlusion Teaching Unit of the University of Valencia. Records were registered at day zero (recession, bleeding on probing, suppuration, probing depth, bone loss and plaque index), at 1, 3 and 6 months. RESULTS: In both groups, a slight increase in recession and disappearance of suppuration took place, and no bone loss was observed during the following 6 months. However, after an initial reduction, probing depth, bleeding on probing and plaque index increased again in the group without keratinized mucosa (KM). CONCLUSIONS: Implants with KM presented better results after non-surgical treatment as well as in their medium-term evolution, although it would be advisable to increase the number of samples in order to achieve greater scientific evidence and standardization in the treatment protocol. CLINICAL RELEVANCE: The role of keratinized mucosa in the development of peri-implantitis has been mentioned in many publications, but less has been emphasized regarding its influence on the success of the treatment of this pathology. The presence of keratinized mucosa has been found to play a key role in the evolution of the non-surgical treatment of peri-implantitis. The amount of keratinized mucosa should be considered in the treatment of peri-implantitis, as well as when planning connective tissue grafts accompanying the decontamination of implants in the absence of keratinized mucosa.
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STATEMENT OF PROBLEM: Anterior veneered zirconia partial fixed dental prostheses (FDPs) have substituted for metal-ceramic to improve esthetics and biocompatibility. However, the material is susceptible to aging or hydrothermal degradation and to chipping of the feldspathic veneer. Whether these susceptibilities limit the clinical performance of anterior veneered zirconia FPDs is unclear. PURPOSE: The purpose of this prospective clinical study was to analyze the mechanical and biologic behavior of zirconia partial FDPs in the anterior region over a 12-year follow-up period. MATERIAL AND METHODS: Twenty-seven 3- to 6-unit FDPs fabricated from zirconia veneered with feldspathic porcelain were placed in the anterior region and examined clinically at 1 month, 6 months, and then annually for 12 years, recording mechanical and biologic outcomes. Raw complication rates and time-to-event Kaplan-Meier analysis was conducted and compared as per the partial fixed dental prosthesis type. RESULTS: Five FDPs had biologic complications (3 with secondary caries, 1 with periapical pathology, 1 with periodontal disease) and 9 had mechanical complications (7 with chipping and 2 with decementation). Chipping was the most prevalent complication and increasingly found with longer-span fixed partial prostheses (P=.007). Five FDPs had to be replaced because of complete failure, the most frequent cause of failure being secondary caries (P=.003). The mean survival rate (no failures) was 11 years 4 months (95% confidence interval, 10.3-12.7). CONCLUSIONS: Zirconia FDPs had an 81.5% survival rate over 12 years. A higher incidence of complications took place during the first 3 years, the most common being chipping.
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Produtos Biológicos , Cárie Dentária , Cárie Dentária/etiologia , Materiais Dentários , Porcelana Dentária/uso terapêutico , Falha de Restauração Dentária , Facetas Dentárias , Prótese Parcial Fixa , Estética Dentária , Humanos , Estudos Prospectivos , Zircônio/uso terapêuticoRESUMO
OBJECTIVE: To evaluate the influence of implant length on marginal bone loss, comparing implants of 4 mm, 6 mm, and >8 mm, supporting two splinted crowns after 36-month functional loading. MATERIALS AND METHODS: this retrospective clinical trial evaluated the peri-implant behavior of splinted crowns (two per case) on pairs of implants of the same length placed in the posterior maxilla (molar area). Implants were divided into three groups according to length (Group 1: extra-short 4 mm; Group 2: short 6 mm; Group 3: conventional length >8 mm). Marginal bone loss was analyzed using standardized periapical radiographs at the time of loading and 36 months later. RESULTS: 24 patients (19 women and 5 men) were divided into three groups, eight rehabilitations per group, in the position of the maxillary first and second molars. The 48 Straumann® Standard Plus (Regular Neck (RN)/Wide Neck (WN)) implants were examined after 36 months of functional loading. Statistical analysis found no significant differences in bone loss between the three groups (p = 0.421). No implant suffered biological complications or implant loss. Long implants were associated with less radiographic bone loss. CONCLUSIONS: extra-short (4 mm); short (6 mm); and conventional length (>8 mm) implants in the posterior maxilla present similar peri-implant bone loss and 100% survival rates in rehabilitation, by means of two splinted crowns after 36 months of functional loading. Implants placed in posterior positions present better bone loss results than implants placed in anterior positions, regardless of the interproximal area where bone loss is measured. Conventional length (>8 mm) implants show better behavior in terms of distal bone loss than short (6 mm) and extra-short (4 mm) implants.
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Perda do Osso Alveolar/diagnóstico , Coroas , Implantes Dentários/classificação , Dente Molar , Falha de Restauração Dentária , Feminino , Seguimentos , Humanos , Masculino , Estudos Retrospectivos , Resultado do TratamentoRESUMO
Short implants are an increasingly common alternative to other surgical techniques in areas where bone availability is reduced. Despite the advantages they offer, a variety of biological repercussions have been described in the literature that can even lead to the loss of these. The aim of this systematic review and meta-analysis was to analyze the impact of the use of short implants on their survival and on peri-implant bone loss, evaluating the influence that length, diameter, and crown-to-implant ratio (C/I) have on these parameters. This systematic review was based on guidelines proposed by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). An electronic search was conducted using terms related to the use of short implants in partially or totally edentulous patients. A total of five databases were consulted in the literature search: PubMed, Embase, Cochrane, Scopus, and Web of Science. After eliminating the duplicate articles and assessing which ones met the inclusion criteria, 15 articles were included for the qualitative analysis and 14 for the quantitative study. Through meta-analysis, the percentage of implant loss and peri-implant bone loss was estimated. Relating these parameters to length, diameter, and C/I ratio, no significant differences have been found for implant loss (values of p = 0.06, 0.10, and 0.9, respectively for length, diameter, and C/I ratio), nor for peri-implant bone loss (values of p = 0.71, 0.72, and 0.36, respectively for length, diameter, and C/I ratio). In conclusion, the use of short implants does not seem to have a significant influence on marginal bone loss or the survival rate of implants.
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BACKGROUND: Calculus accumulation varies widely between individuals. Dental calculus has been associated with the principal periodontal diseases. The aim of this study was to analyze individual characteristics, and salivary and microbiological parameters among patients considered to be rapid calculus formers and patients who form calculus slowly. METHODS: Individual characteristics were recorded in a sample of 74 patients (age, sex, smoking, periodontal diagnosis, and dental crowding), as well as salivary parameters (unstimulated saliva flow, pH, and biochemical analysis of saliva) and microbiological parameters (by means of semi-quantitative polymerase chain reaction (PCR) analysis). RESULTS: A statistically significant association (p = 0.002) was found between the rate of calculus formation and the diagnosis of periodontal disease. A greater presence of dental crowding was observed among the group of rapid calculus formers. Urea and phosphorus levels were higher among rapid calculus formers. Regarding microbiological parameters, differences were found in Streptococcus mutans, this being higher in the group of slow formers. CONCLUSIONS: Rapid calculus formation appears to be linked to patients diagnosed with more severe periodontal diseases. Rapid calculus-forming patients present more dental crowding and a lower proportion of S. mutans.
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Background and objectives: To compare the medium- to long-term mechanical behavior of overdentures with two different retention systems: overdentures with Locator® axial retention, and vertical insertion overdentures with bar retention, used to rehabilitate edentulous maxillar. Material and Methods: This prospective study assessed patients presenting complete maxillary edentulism, rehabilitated by means of implant-supported overdentures (n = 20), 10 with Locator® axial retention (ODA group) and 10 with overdentures on bars (ODB group). Patients also completed a questionnaire to determine their satisfaction with treatment. Results: The mean follow-up time in both groups was 11.4 years, with follow-up times in both groups ranging from 5 to 14 years. The ODA group suffered mechanical complications such as retention loss, need for nylon retention insert changes, resin fracture, and need for relining. In the ODB group, prosthetic dental wear, screw loosening, and complete prosthetic failure were more common. A total of 19 implants failed (23.8%); of these, 11 were in the ODA group (failure rate = 27.5%) and eight in the ODB group (failure rate = 20%). The patient satisfaction questionnaire obtained a mean score of 7.9 out of 10 in the ODA group, and 9.75 in the ODB group. Conclusions: in rehabilitations of edentulous maxillar by means of implant-supported overdentures, both the systems assessed were shown to be effective in the medium to long term. Patients expressed a high level of satisfaction with the treatments received.
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Implantes Dentários/efeitos adversos , Retenção em Prótese Dentária/tendências , Revestimento de Dentadura/efeitos adversos , Boca Edêntula/reabilitação , Idoso , Estudos de Coortes , Implantes Dentários/psicologia , Retenção em Prótese Dentária/psicologia , Prótese Dentária Fixada por Implante/psicologia , Prótese Dentária Fixada por Implante/estatística & dados numéricos , Falha de Restauração Dentária/estatística & dados numéricos , Revestimento de Dentadura/psicologia , Feminino , Seguimentos , Humanos , Masculino , Fenômenos Mecânicos , Boca Edêntula/cirurgia , Satisfação do Paciente , Estudos Prospectivos , Inquéritos e Questionários/normas , Resultado do TratamentoRESUMO
STATEMENT OF PROBLEM: Because of market demand for innovation, new restoration materials have been introduced without adequate testing; clinical failure may be the consequence, and clinical studies are needed. PURPOSE: The purpose of this clinical study was to evaluate the biological and mechanical clinical behavior of implant-supported resin-modified ceramic crowns compared with that of metal-ceramic crowns. MATERIAL AND METHODS: Forty-two participants aged between 35 and 65 years received single implants in posterior edentulous sites. After the osseointegration period, half of the implants (selected randomly) (n=25) were restored with metal-ceramic crowns (MC group) and the other half with resin-modified ceramic crowns (RMC group) bonded with dual-polymerized resin cement onto titanium abutments. The biomechanical state of the restorations and implants was analyzed. RESULTS: Mean peri-implant bone loss after 5 years of functional life was 0.3 ±0.6 mm. The implant clinical survival rate was 98%. RMC crowns had a survival rate of 70%, whereas MC crowns had a 100% survival rate. RMC crowns had more mechanical complications than the MC group (P<.001). Peri-implant bone loss showed no significant differences between crown type (P=.175). CONCLUSIONS: All peri-implant bone loss values were within the range considered acceptable. Metal-ceramic crowns showed better mechanical behavior than resin-modified ceramic crowns. Biological responses of peri-implant tissue would appear to be independent of the type of cemented crown.
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Implantes Dentários , Falha de Restauração Dentária , Cerâmica , Coroas , Dente Suporte , Porcelana Dentária , Prótese Dentária Fixada por Implante , Metais , Estudos Prospectivos , ZircônioRESUMO
PURPOSE: To analyze peri-implant bone loss around six different types of implant-prosthetic connections over a 2-year follow-up period. MATERIALS AND METHODS: A total of 120 implants were divided into six groups (n = 20), three with crestally and three with supracrestally placed implants, with different internal connections, placed in posterior sectors (molar and premolar), and bearing one-piece CAD/CAM restorations screwed directly to each implant's prosthetic platform. Bone height was measured from parallelized periapical radiographs taken at the moment of loading and 2 years later. RESULTS: The patient sample included 61 subjects, 36 men and 25 women. Significant differences were found in bone loss between groups, the implant with internal hex and convergent transmucosal collar showing the least bone loss (P < .001) in comparison with the other designs. Supracrestally placed implants underwent less bone loss than crestally placed implants (P = .025). CONCLUSION: Peri-implant bone loss is influenced by the level of implant placement in relation to the bone crest (crestal or supracrestal) and by the morphology of the prosthetic platform.
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Perda do Osso Alveolar , Implantes Dentários , Dente Pré-Molar , Implantação Dentária Endóssea , Planejamento de Prótese Dentária , Feminino , Seguimentos , Humanos , Masculino , Estudos ProspectivosRESUMO
BACKGROUND: To evaluate color changes to composite resins used to restore extracted teeth compared with composite discs after whitening with two agents: hydrogen peroxide (HP) and carbamide peroxide (CP). MATERIAL AND METHODS: Ten human molars with class V vestibular and palatine cavity preparation obturated with Vita hybrid nanocomposite were hemisected to obtain 20 specimens assigned randomly to two groups: O1 and O2. Twenty composite discs were divided into two groups: D1 and D2. The groups O1 and D1 were treated with 16% CP, while groups =2 and D2 were treated with 37.5 % HP. Chromaticity coordinates L*, a* and b* were registered using a spectrophotometer. RESULTS: Statistically significant differences were found in O1 for L* and a*, in O2 for all three coordinates, and in D1 and D2 only for L*. Comparisons between groups found significant differences in ΔEe (end of treatment) between O1 and O2, between O2 and D2, and between D1 and O1. CONCLUSIONS: Both whitening agents produced significant decreases in the three-color components of composites used for dental restorations, while color changes to composite discs were limited to changes in luminosity. HP produced a greater color change to composite dental restorations than to composite discs. Key words:In vitro study, whitening agents, hydrogen peroxide, and carbamide peroxide, dental restorations.
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Background: The aim of this study was to compare a conventional technique (elastomeric impression material - EIM) and a digital technique (scanner digital model - SDM) on a six-analog master model (MM) to determine which was the most exact. Material and Methods: Twenty impressions were taken of a master model (EIM) and twenty scanned impressions (SDM) (True Definition). A coordinate measuring machine (CMM) was used to measure the distances between adjacent analogues (1-2, 2-3, 3-4, 4-5, 5-6), intermittently positioned analogues (1-4, 3-6) and the most distal (1-6). Reference values were established from the master model, which were compared with the two impression techniques. The significance level was established as 5% (p<0.05). Results: The precision of each technique was compared with MM. For adjacent analogues (1-2), no significant differences were found between EIM-MM (p=0,146). For intermittently positioned analogues (1-4), SDM did not show significant differences with MM (p=0.255). For the distance between distal analogues (1-6), significant differences were found between both tecniques and MM (p=0.001). Conclusions: In a clinical situation with < three implants, EIM is more exact than SDM, but in cases of four implants SDM is more exact. For rehabilitations (> four implants), neither technique can be considered accurate although error falls within the tolerance limits established in the literature (30-150μm)
No disponible
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Humanos , Implantação Dentária Endóssea/métodos , Técnica de Moldagem Odontológica , Planejamento de Prótese Dentária/métodos , Elastômeros , Técnicas In Vitro/métodos , Modelos Anatômicos , Arco Dental/diagnóstico por imagemRESUMO
Purpose: The objective of this prospective randomized clinical trial (RCT) was to analyze and compare the clinical behavior of three types of prosthesis supported by single implants in the posterior region after three years of functional loading. Materials and methods: Seventy-five implants were divided into three groups according to the type of prosthetic restoration: screw-retained crown (group GS); cemented crown without finishing line (biologically oriented preparation technique) (group GBOPT); and conventional cemented crown with finishing line (group GCC). After three years in function, clinical parameters (presence of keratinized mucosa, probing depths, bleeding on probing, and radiographic bone loss) were compared between the three experimental groups. The possible correlation between soft tissue clinical parameters and bone loss was also analyzed. Results: Statistical analysis found significant differences in clinical parameters between the different types of crown, with the cemented restoration without finishing line (BOPT) presenting fewer complications and better peri-implant health outcomes including: significantly different KMW data (mm), with significant differences between groups GBOPT and GCC (p < 0.001, Kruskal-Wallis test), with GBOPT obtaining larger quantities of keratinized mucosa (KM); statistically significant differences in probing depth (PD) values between groups GBOPT and GCC (p = 0.010, Kruskal-Wallis test); significant differences in bleeding on probing (BOP) between groups GBOPT and GCC (p = 0.018, Chi2 test) in favor of GBOPT. Conclusions: Soft tissue behavior around implants is related to the type of prosthetic restoration used, with cemented prostheses with BOPT presenting better peri-implant soft tissue behavior.
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A patient of 58 years of age without medical problems came to the clinic due to missing teeth in the upper posterior region and to change the partial fixed prosthesis in the upper anterior area. Proposed treatment: surgical phase of three conical shape tapering implants with prosthetic platform in occlusal direction with mechanize collar tissue level with fixtures to place implant-supported metal-ceramic restorations. In the anterior area, a zirconium oxide fixed partial prosthesis was vertical preparation of the tooth's. When preparing teeth to receive fixed prostheses, the definition and shape of finish lines has been a subject of endless discussion, modification, and change ever since the beginnings of restorative prosthetic dentistry. The BOPT technique (biologically oriented preparation technique) was first described in the context of tooth-supported restorations but has recently been applied to dental implants with the aim of ensuring healthy peri-implant tissue and creating the possibility of modeling the peri-implant sulcus by modifying prosthetic emergence profiles. Vertical preparation of teeth and abutments without finish line on implants is a technique which was found to be adequate for ensuring the remodeling and stability of peri-implant tissues. Key words:Peri-implant tissue health, shoulderless abutments.
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The aim of this work was to observe the behavior of osteoblast cells cultured in vitro on titanium discs in relation to disc surface roughness and the addition of melatonin to the culture medium. MG63 osteoblast cells were cultivated on 120 Grade 5 Ti divided into three groups: Group E, treated with dual acid etch; Group EP, treated with dual acid etch and calcium phosphate; and Group M, machined. Surface roughness was examined under a laser scanning confocal microscope (CLSM) and scanning electron microscopy (SEM). The proliferation and morphology of cells were determined under fluorescence microscopy and SEM. Messenger ribonucleic acid (mRNA) of different genes related to osteoblastic differentiation was quantified by means of real-time quantitative polymerase chain reaction (RT-PCR) assay. The greatest surface roughness was found in Group EP (Ra 0.354 µm), followed by Group E (Ra 0.266 µm), and Group M (Ra 0.131 µm), with statistically significant differences between the groups (p < 0.001). In the presence of melatonin a trend to a higher cell proliferation was observed in all groups although significant differences were only found in Group M (p = 0.0079). Among the genes studied, a significant increase in phosphate-regulating neutral endopeptidase, X-linked (PHEX) expression was observed in cells cultured on EP discs. The addition of melatonin increased osteoblast cell proliferation and differentiation, and may favor the osseointegration of dental implants.
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Diferenciação Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Melatonina/farmacologia , Titânio/química , Adesão Celular/efeitos dos fármacos , Linhagem Celular , Humanos , Microscopia Confocal , Microscopia Eletrônica de Varredura , Osteoblastos/citologia , Osteoblastos/efeitos dos fármacos , Osteoblastos/metabolismo , RNA Mensageiro/metabolismo , Propriedades de SuperfícieRESUMO
PURPOSE: To compare the effectiveness of different methods of fractured screw fragment retrieval from dental implants, comparing a conventional method (use of an exploration probe and ultrasonic tips) with two mechanical retrieval kits. MATERIALS AND METHODS: One hundred thirty-five screws in implant internal connections were fractured to test fragment retrieval comparing three methods: conventional method with the use of an explorer probe and ultrasonic tips (group CE), extraction with a mechanical kit with a guide cylinder (group MK1), and extraction with a mechanical kit without a guide cylinder (group MK2). Extraction success and retrieval times for each method, as well as success and retrieval times in relation to fracture depth-coronal, middle, or apical-were analyzed by means of chi-square, Fisher exact, Kruskal-Wallis, and Mann-Whitney tests (P < .05). The integrity of implant internal threads was also analyzed. RESULTS: The extraction success rates for groups MK2, CE, and MK1 were 93.3%, 73.3%, and 20%, respectively. The mean ± SD extraction times were 2 minutes, 56 seconds ± 2 minutes, 9 seconds; 3 minutes, 15 seconds ± 1 minute, 48 seconds; and 13 minutes, 34 seconds ± 7 minutes, 25 seconds for groups MK2, CE, and MK1, respectively. Statistically significant differences were found in the number of fractured screws extracted and in the retrieval time. No significant differences were found for retrieval time or extraction success in relation to the depth of the fracture. CONCLUSION: The mechanical kit without the guide cylinder achieved the best results with respect to the number of screw fragments retrieved, retrieval time, and preservation of implant internal threads.
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BACKGROUND: Cytokines and chemokines have been analysed in patients with oral squamous cell carcinoma and potentially malignant disorders. We selected interleukin-6 (IL-6) because it is a multifunctional interleukin reported to be altered in potentially malignant oral disorders and in malignant lesions. To date, this has not been evaluated or tested in proliferative verrucous leukoplakia (PVL), however. OBJECTIVES: This study aimed to analyse the differences in serum and saliva IL-6 levels among patients with PVL, oral squamous cell carcinoma (OSCC) and healthy controls and to examine the relationship between salivary IL-6 levels and the extent of the verrucous area. METHODS: Using an enzyme-linked immunosorbent assay, we determined the serum and saliva IL-6 levels in three groups: 20 patients with PVL, 20 with OSCC and 20 healthy controls. RESULTS: There were significant (p < 0.01) differences in the serum and saliva IL-6 levels among the three groups and among the three grades of extent of the verrucous areas (p = 0.01). In the OSCC group, there was a significant difference in the saliva IL-6 levels between patients with and without lymph node metastasis at diagnosis (p = 0.02). CONCLUSIONS: We found that patients with OSCC had the highest salivary and serum IL-6 levels, while PVL had lower values than OSCC, but higher than the controls, and these altered levels were associated with the extent of the verrucous areas. CLINICAL RELEVANCE: Salivary and plasma IL-6 are altered in patients with PVL, with more extensive verrucous areas being associated to the highest IL-6 levels. This could be a significant tool for monitoring patients with PVL, their progression to more advances stages and their recurrences.
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Interleucina-6/análise , Leucoplasia Oral/imunologia , Carcinoma de Células Escamosas , Estudos de Casos e Controles , Humanos , Leucoplasia , Neoplasias Bucais , Recidiva Local de Neoplasia , Saliva/químicaRESUMO
BACKGROUND: The aim of this in vitro study was to compare the mechanical failure behavior and to analyze fracture characteristics of metal ceramic crowns with two veneering systems - press-on metal (PoM) ceramic versus a conventional veneering system - subjected to static compressive loading. MATERIAL AND METHODS: Forty-six crowns were constructed and divided into two groups according to porcelain veneer manufacture. Group A: 23 metal copings with porcelain IPS-InLine veneering (conventional metal ceramic). Group B: 23 metal copings with IPS-InLine PoM veneering porcelain. After 120,000 fatigue cycles, the crowns were axially loaded to the moment of fracture with a universal testing machine. The fractured specimens were examined under optical stereomicroscopy and scanning electron microscope. RESULTS: Fracture resistance values showed statistically significant differences (Student's t-test) regarding the type of ceramic veneering technique (p=0.001): Group A (conventional metal ceramics) obtained a mean fracture resistance of 1933.17 N, and Group B 1325.74N (Press-on metal ceramics). The most common type of fracture was adhesive failure (with metal exposure) (p=0.000). Veneer porcelain fractured on the occlusal surface following a radial pattern. CONCLUSIONS: Metal ceramic crowns made of IPS InLine or IPS InLine PoM ceramics with different laboratory techniques all achieved above-average values for clinical survival in the oral environment according to ISO 6872. Crowns made with IPS InLine by conventional technique resisted fracture an average of 45% more than IPS InLine PoM fabricated with the press-on technique. Key words:Mechanical failure, conventional feldspathic, pressable ceramic, chewing simulator, thermocycling, compressive testing, fracture types, scanning electron microscope.
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STATEMENT OF PROBLEM: Because of the high mechanical strength of zirconium dioxide, the metal in fixed partial prostheses can now be replaced. However, the material is susceptible to aging or hydrothermal degradation and to chipping of the feldspathic veneer. PURPOSE: The purpose of this prospective study was to evaluate the survival (without failure) and success (survival without any complication or failure) rate and clinical efficacy of anterior zirconia partial fixed dental prostheses. MATERIAL AND METHODS: Twenty-seven anterior partial fixed dental prostheses of 3 to 6 units were fabricated. All participants were examined after 1 month and 6 months, then annually for 7 years. RESULTS: Three partial fixed dental prostheses failed and had to be removed: 2 because of secondary caries, which increased failure significantly (P=.001) and 1 because of severe chipping. Six partial fixed dental prostheses had complications: 2 debonded, 3 had chipping, and 1 had periapical pathology. All veneer porcelain fractures occurred in 6-unit fixed partial prostheses (P=.002). The clinical success rate was 88.8% after the 7-year follow-up. CONCLUSIONS: The clinical behavior of partial fixed dental prostheses with a zirconium dioxide core in the anterior region provides an adequate medium-term survival rate. The main cause of failure was secondary caries. The most frequent complication was chipping, which was directly related to the number of units of the prosthesis.
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Materiais Dentários/química , Prótese Parcial Fixa , Zircônio/química , Adulto , Idoso , Desenho Assistido por Computador , Cárie Dentária/etiologia , Porcelana Dentária/química , Falha de Restauração Dentária , Facetas Dentárias , Planejamento de Dentadura , Retenção de Dentadura , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Doenças Periapicais/etiologia , Estudos Prospectivos , Recidiva , Propriedades de Superfície , Análise de Sobrevida , Resultado do TratamentoRESUMO
OBJECTIVES: To observe human osteoblast behavior cultured in vitro on titanium discs (Ti) in relation to surface roughness and melatonin application. Study DESIGN: Human osteoblasts (MG-63) were cultured on 60 Ti6Al4V discs divided into three groups: GroupI: discs treated with dual acid etching; Group II dual acid etching and blasting with calcium phosphate particles; Group III (control) machined discs. Surface roughness and topography of the discs were examined with scanning electron microscope (SEM) and confocal laser scanning electron microscope( CLSM).Osteoblast adhesion, proliferation and cell morphology were determined by means of fluorescence microscopy with Image-Pro Plus software and SEM. RESULTS: Group II presented the roughest discs, while the least rough were Group III. Cell adhesion was greatest in Group II. The addition of melatonin improved cell proliferation. CONCLUSIONS: 1. Surface treatments (dual acid etching, calcium phosphate impaction) increase surface roughness in comparison with machined titanium.2. Greater surface roughness tends to favor cell adhesion after 24-hour cell culture.3. The addition of melatonin tends to favor osteoblast proliferation