RESUMO
Osteoporosis is considered a risk factor for osseointegration during implant treatment. Photofunctionalization of titanium has been shown to improve bone-based cell adhesion, proliferation, and functional expression, increasing the bone-implant contact rate and bone-implant integration strength. This study aimed to test the hypothesis that photofunctionalization is effective for implant fixation using an osteoporosis rat model. In the biomechanical push-in test, the bone-implant integration strength of the photofunctionalization treatment group was 1.53 times that of the control group (p<0.05). These values implied that photofunctionalization restored the ovariectomy-induced low bone-implant integration strength to normal states. In the micro-CT analysis, the BV/TV of the photofunctionalization treatment group was 1.32 times that of the control group (p<0.05). These values implied that photofunctionalization restored the ovariectomy-induced low peri-implant bone formation to normal states. These results indicate that photofunctionalization treatment increased peri-implant bone formation and bone-implant integration strength in ovariectomized rats.
Assuntos
Osteoporose , Titânio , Feminino , Ratos , Animais , Ratos Sprague-Dawley , Titânio/farmacologia , Osseointegração , OsteogêneseRESUMO
PURPOSE: To investigate the effect of prosthodontic treatment on the ingestible food profile in adult Japanese outpatients, and to identify the related risk factors that can deteriorate the profile. METHODS: The participants were 277 outpatients who visited university-based specialty clinics in Japan for prosthodontic treatment. The demographic data, number of present teeth assessed via intraoral examination, and oral health-related quality of life assessed by the total Oral Health Impact Profile (OHIP-J54) scores of all participants were recorded before treatment. Ingestible food profile score (IFS) was recorded using a validated food intake questionnaire. Eligible participants who answered the questionnaire before and after treatment were categorized into five groups based on the prosthodontic treatments they received (i.e., crowns, bridges, removable partial dentures, removable complete dentures, and removable complete and partial dentures). RESULTS: Multivariate analysis of covariance revealed a statistically significant main effect of prosthodontic intervention (time course: before and after treatment) on mean IFS (P=0.035, F=4.526), even after adjusting for covariates (age, number of present teeth, and treatment modality). Multiple linear regression analysis revealed that the low number of present teeth (r=0.427, P<0.001) and a high OHIP-J54 total score (r=-0.519, P<0.001) of the patients at the baseline were significantly associated with their baseline IFSs, even after adjusting for confounding variables. CONCLUSIONS: The findings of this multicenter follow-up study indicate the importance of prosthodontic rehabilitation in improving patients' ingestible food profiles.
Assuntos
Prótese Parcial Removível , Qualidade de Vida , Adulto , Humanos , População do Leste Asiático , Seguimentos , Saúde Bucal , Pacientes Ambulatoriais , Prostodontia , Alimentos , DietaRESUMO
The aim of this study was to evaluate the NaOCl-mediated biofunctionalization of titanium surfaces. Titanium disks stored for 2 weeks were immersed in 5% NaOCl solution for 24 h. A disk immersed in distilled water for 24 h was used as a control. X-ray photoelectron spectrometer assay of the titanium surface after NaOCl treatment demonstrated that organic contaminants containing carbon and nitrogen were removed and the number of hydroxyl groups increased. The NaOCl treatment substantially converted the titanium surface to superhydrophilic status (θ<5°), which resulted in an increased number of attached cells and enhanced cell spreading on the NaOCl-treated surfaces. These results indicate that biofunctionalization of the biologically degraded titanium surfaces can be achieved by chemical surface treatment with 5% NaOCl. The mechanism for desorption of strongly adsorbed organic molecules with polar groups such as amino and aldehyde groups from titanium surfaces by ClO- was elucidated.
Assuntos
Titânio , Propriedades de SuperfícieRESUMO
PURPOSE: To examine the bioactivity of differently aged titanium (Ti) disks and to determine whether ultraviolet (UV) light treatment reverses the possible adverse effects of Ti aging. MATERIALS AND METHODS: Ti disks with three different surface topographies were prepared: machined, acid-etched, and sandblasted. The disks were divided into three groups: disks tested for biologic capacity immediately after processing (fresh surfaces), disks stored under dark ambient conditions for 4 weeks, and disks stored for 4 weeks and treated with UV light. The protein adsorption capacity of Ti was examined using albumin and fibronectin. Cell attraction to Ti was evaluated by examining migration, attachment, and spreading behaviors of human osteoblasts on Ti disks. Osteoblast differentiation was evaluated by examining alkaline phosphatase activity, the expression of bone-related genes, and mineralized nodule area in the culture. RESULTS: Four-week-old Ti disks showed = or < 50% protein adsorption after 6 hours of incubation compared with fresh disks, regardless of surface topography. Total protein adsorption for 4-week-old surfaces did not reach the level of fresh surfaces, even after 24 hours of incubation. Fifty percent fewer human osteoblasts migrated and attached to 4-week-old surfaces compared with fresh surfaces. Alkaline phosphatase activity, gene expression, and mineralized nodule area were substantially reduced on the 4-week-old surfaces. The reduction of these biologic parameters was associated with the conversion of Ti disks from superhydrophilicity to hydrophobicity during storage for 4 weeks. UV-treated 4-week-old disks showed even higher protein adsorption, osteoblast migration, attachment, differentiation, and mineralization than fresh surfaces, and were associated with regenerated superhydrophilicity. CONCLUSIONS: Time-related degradation of Ti bioactivity is substantial and impairs the recruitment and function of human osteoblasts as compared to freshly prepared Ti surfaces, suggesting a "biologic aging"-like change of Ti. UV treatment of aged Ti, however, restores and even enhances bioactivity, exceeding its innate levels.
Assuntos
Materiais Biocompatíveis , Osteoblastos/citologia , Titânio/química , Titânio/efeitos da radiação , Raios Ultravioleta , Adsorção/efeitos da radiação , Animais , Materiais Biocompatíveis/química , Materiais Biocompatíveis/efeitos da radiação , Bovinos , Adesão Celular , Movimento Celular , Células Cultivadas , Fibronectinas/química , Humanos , Osseointegração , Osteoblastos/metabolismo , Osteoblastos/fisiologia , Osteocalcina/biossíntese , Osteopontina/biossíntese , Albumina Sérica/química , Propriedades de Superfície , Fatores de Tempo , MolhabilidadeRESUMO
OBJECTIVES: The aim of this study was to investigate whether the newly developed artificial dental plaque (A-DP) is useful as an educational tool for denture care of dental hygienist that compared it with conventional artificial dental plaque from the viewpoint of practical skills. MATERIAL AND METHODS: The 125 dental hygienist school students and 26 dental hygienists who had clinical experience were subjected a practical training of denture plaque control using the conventional denture plaque (C-DP) and the A-DP. The questionnaires based on the semantic differential method were used to survey whether the A-DP is similar to the real denture plaque (R-DP). Factor analysis by rotation of promax was carried out. RESULTS: In the results of the factor analysis, the two factors could be detected in students and three factors in dental hygienists. The total score of each denture plaque was calculated for each factor, and correlation coefficient was examined. There was significant correlation between the A-DP and the R-DP at the first factors, both students and dental hygienists. C-DP was not similar to R-DP in all factors. CONCLUSIONS: These results suggested that A-DP resembles R-DP better than C-DP. It was concluded that the A-DP was similar to the R-DP and could be a potent educational tool for practical denture care.
Assuntos
Assistência Odontológica/métodos , Higienistas Dentários/educação , Placa Dentária/terapia , Dentaduras/microbiologia , Modelos Dentários , Higienistas Dentários/estatística & dados numéricos , Dentaduras/efeitos adversos , Feminino , Humanos , Estudantes/estatística & dados numéricosRESUMO
The aim of this study was to improve the cytocompatibility and differentiation of human bone marrow-derived mesenchymal stem cells on the surface of titanium implants by immobilizing biofunctional molecules on their surface. Gly-Arg-Gly-Asp-Ser (GRGDS) peptides, human plasma fibronectin (pFN), or type I collagen from calf skin (Col) was covalently immobilized on the titanium surfaces. Twice as many cells attached to the Col- and pFN-immobilized titanium surfaces than attached to the as-polished surface control. The ALP activity of the cells, as well as the mineralized nodule formation, was significantly higher on the Col- and pFN-immobilized titanium surfaces than on the as-polished surfaces. These results indicate that the immobilization of biofunctional molecules such as Col and pFN on titanium surfaces enhances the attachment, spreading, proliferation, and differentiation of human bone marrow-derived mesenchymal stem cells, which may lead to a more rapid bone-titanium integration.
Assuntos
Células-Tronco Mesenquimais , Adesão Celular , Diferenciação Celular , Proliferação de Células , Células Cultivadas , Colágeno Tipo I , Humanos , Osteoblastos , Osteogênese , Propriedades de Superfície , TitânioRESUMO
PURPOSE: The Japan Prosthodontic Society developed a multi-axis assessment protocol to evaluate the complex variations in patients who need prosthodontic care, and to classify the level of treatment difficulty. A previous report found the protocol to be sufficiently reliable. The purpose of this multi-center cohort study was to evaluate the validity of this multi-axis assessment protocol. METHODS: The treatment difficulty was evaluated using the multi-axis assessment protocol before starting prosthodontic treatment. The time required for active prosthodontic treatment, medical resources such as treatment cost, and changes in the oral health-related QOL before and after treatment, were evaluated after treatment completion. The construct validity of this protocol was assessed by the correlation between the dentist's pre-operative subjective assessment of the treatment difficulty, and the level of difficulty determined by this protocol. The predictive validity was assessed estimating the correlations between a "comprehensive level of treatment difficulty" based on the four axes of this protocol and total treatment cost, total treatment time, and changes in the oral health-related QOL before and after treatment. RESULTS: The construct validity of this protocol was well documented except for psychological assessment. Regarding the predictive validity, the comprehensive level of treatment difficulty assessed before treatment was significantly correlated with the three surrogate endpoints known to be related to the treatment difficulty (total treatment cost, treatment time, and improvement in the oral health-related QOL). To further clarify the validity of the protocol according to patients' oral condition, a subgroup analysis by defects was performed. Analyses revealed that treatment difficulty assessment before treatment was significantly related to one or two surrogate endpoints in the fully edentulous patients and the partially edentulous patients. No significant relationship was observed in the patients with mixture of full/partial edentulism and the patients with teeth problems, possibly due to the small sample size in these groups. CONCLUSION: This study revealed that the multi-axis assessment protocol was sufficiently valid to predict the level of treatment difficulty in prosthodontic care in patients with fully edentulous defects and with partially edentulous defects.
Assuntos
Boca Edêntula/reabilitação , Avaliação de Processos em Cuidados de Saúde/métodos , Prostodontia , Sociedades Odontológicas/organização & administração , Estudos de Coortes , Previsões , Humanos , Japão , Boca Edêntula/psicologia , Saúde Bucal , Prostodontia/economia , Prostodontia/métodos , Prostodontia/organização & administração , Qualidade de Vida , Fatores de TempoRESUMO
PURPOSE: The Japan Prosthodontic Society (JPS) has proposed a new diagnostic nomenclature system (DNS), based on pathogenesis and etiology, to facilitate and improve prosthodontic treatment. This system specifies patient disability and the causative factor (i.e. "B (disability) caused by A (causative factor)"). The purpose of this study was to examine the reliability and validity of this DNS. STUDY SELECTION: The JPS Clinical Guideline Committee assessed mock patient charts and formulated disease names using the new DNS. Fifty validators, comprising prosthodontic specialists and dental residents, made diagnoses using the same patient charts. Reliability was evaluated as the consistency of the disease names among the validators, and validity was evaluated using the concordance rate of the disease names with the reference disease names. RESULTS: Krippendorff's α was 0.378 among all validators, 0.370 among prosthodontic specialists, and 0.401 among dental hospital residents. Krippendorff's α for 10 validators (3 specialists and 7 residents) with higher concordance rates was 0.524. Two validators (1 specialist and 1 resident) with the highest concordance rates had a Krippendorff's α of 0.648. Common disease names had higher concordance rates, while uncommon disease names showed lower concordance rates. These rates did not show correlation with clinical experience of the validator or time taken to devise the disease name. CONCLUSIONS: High reliability was not found among all validators; however, validators with higher concordance rates showed better reliability. Furthermore, common disease names had higher concordance rates. These findings indicate that the new DNS for prosthodontic dentistry exhibits clinically acceptable reliability and validity.
Assuntos
Diagnóstico Bucal/métodos , Prostodontia/métodos , Humanos , Japão , Reprodutibilidade dos TestesRESUMO
Although the localization of the proteoglycan/glycosaminoglycan (GAG) complex at the bone-titanium implant interface has been implied, the role of proteoglycans on the establishment of bone-titanium integration is unknown. The hypothesis to be tested was that proteoglycans play an important role in establishing bone-titanium interfacial adhesion. The objective of this study is to investigate the effect of proteoglycan knockdown by GAG enzymatic degradation on the interfacial strength between mineralized tissue and titanium having different surface topographies. Rat bone marrow-derived osteoblastic cells were cultured on either a machined titanium disk or an acid-etched titanium disk. At day 21 of culture, one of the three following GAG degradation enzymes was added into the culture; chondroitinase AC, chondroitinase B, or keratanase. After 3 days of incubation (at day 24 of culture), the laser spallation technique was applied to the samples in order to assess the tissue-titanium interfacial strength. In this technique, a laser-generated stress wave is used to separate the tissue-titanium interface, and the interfacial strength is determined interferometrically by recording the transient free surface velocity of the tissue. Mineralized tissue cultured on the acid-etched titanium showed 20-30% higher tissue interfacial strength than that cultured on the machined titanium (p < 0.0001). For both the machined and acid-etched surface cultures, administration of the enzyme reduced the interfacial strength by 25-30% compared with the untreated control cultures (p < 0.0001). There were no differences in the effect among the three different enzymes tested. A nanoindentation study revealed that the enzyme treatment did not affect the elastic modulus of the mineralized tissue. Scanning electron microscopic and energy dispersive spectroscopic analyses revealed less post-spallation tissue remnant on the titanium substrates when treated with the enzymes. The tissue remnant was greater in amount on the acid-etched surface than on the machined surface. The results suggest that there exists not only mechanical interlocking but also biological interfacial adhesion between the mineralized tissue and titanium, in which the proteoglycan/GAG complex is involved.
Assuntos
Materiais Biocompatíveis , Glicosaminoglicanos/metabolismo , Titânio , Animais , Masculino , Osteoblastos , Ratos , Ratos Sprague-DawleyRESUMO
PURPOSE: Dentists may encounter patients who present with a sense of a malocclusion but in whom no objective findings can be detected. For the patient who insists that there is occlusal discomfort, in the absence of evidence some dentists elect to perform an occlusal adjustment that not only fails to alleviate symptoms, and may, in fact, exacerbate the discomfort. The patient-dentist relationship is then likely compromised because of a lack of trust. STUDY SELECTION: In 2011, the Clinical Practice Guidelines Committee of the Japan Prosthodontic Society formulated guidelines for the management of occlusal discomfort. When formulating clinical practice guidelines, the committee bases their recommendations on information derived from scientific evidence. For "occlusal dysesthesia," however, there are an insufficient number of high-quality papers related to the subject. Therefore, a consensus meeting was convened by the Japan Prosthodontic Society to examine evidence in the Japanese- and English-language literature and generate a multi-center survey to create an appropriate appellation for this condition. RESULTS: As a result of the consensus meeting and survey findings, this condition may be justifiably termed "occlusal discomfort syndrome." CONCLUSIONS: The Japan Prosthodontics Society believes that identification of an umbrella term for occlusal discomfort might serve as a useful guide to formulating clinical practice guidelines in the future. This position paper represents summary findings in the literature combined with the results of a multicenter survey focused on dental occlusal treatment and the condition of patients who present with occlusal discomfort syndrome.
Assuntos
Má Oclusão/psicologia , Má Oclusão/terapia , Ajuste Oclusal/efeitos adversos , Guias de Prática Clínica como Assunto , Prostodontia/organização & administração , Sensação , Adulto , Idoso , Progressão da Doença , Feminino , Humanos , Japão , Masculino , Pessoa de Meia-Idade , SíndromeRESUMO
UNLABELLED: This study revealed that osteoblasts generate harder, stiffer, and more delamination-resistant mineralized tissue on titanium than on the tissue culture polystyrene, associated with modulated gene expression, uniform mineralization, well-crystallized interfacial calcium-phosphate layer, and intensive collagen deposition. Knowledge of this titanium-induced alteration of osteogenic potential leading to enhanced intrinsic biomechanical properties of mineralized tissue provides novel opportunities and implications for understanding and improving bone-titanium integration and engineering physiomechanically tolerant bone. INTRODUCTION: Bone-titanium integration is a biological phenomenon characterized by continuous generation and preservation of peri-implant bone and serves as endosseous anchors against endogenous and exogenous loading, of which mechanisms are poorly understood. This study determines the intrinsic biomechanical properties and interfacial strength of cultured mineralized tissue on titanium and characterizes the tissue structure as possible contributing factors in biomechanical modulation. MATERIALS AND METHODS: Rat bone marrow-derived osteoblastic cells were cultured either on a tissue culture-grade polystyrene dish or titanium-coated polystyrene dish having comparable surface topography. Nano-indentation and nano-scratch tests were undertaken on mineralized tissues cultured for 28 days to evaluate its hardness, elastic modulus, and critical load (force required to delaminate tissue). Gene expression was analyzed using RT-PCR. The tissue structural properties were examined by scanning electron microscopy (SEM), collagen colorimetry and localization with Sirius red stain, mineral quantification, and localization with von Kossa stain and transmission electron microscopy (TEM). RESULTS: Hardness and elastic modulus of mineralized tissue on titanium were three and two times greater, respectively, than those on the polystyrene. Three times greater force was required to delaminate the tissue on titanium than that on the polystyrene. SEM of the polystyrene culture displayed a porous structure consisting of fibrous and globular components, whereas the titanium tissue culture appeared to be uniformly solid. Cell proliferation was remarkably reduced on titanium. Microscopic observations revealed that the mineralized tissue on titanium was composed of uniform collagen-supported mineralization from the titanium interface to the outer surface, with intensive collagen deposition at tissue-titanium interface. In contrast, tissue on the polystyrene was characterized by collagen-deficient mineralization at the polystyrene interface and calcium-free collagenous matrix formation in the outer tissue area. Such characteristic microstructure of titanium-associated tissue was corresponded with upregulated gene expression of collagen I and III, osteopontin, and osteocalcin mRNA. Cross-sectional TEM revealed the apposition of a high-contrast and well-crystallized calcium phosphate layer at the titanium interface but not at the polystyrene interface. CONCLUSIONS: Culturing osteoblasts on titanium, compared with polystyrene, enhances the hardness, elastic modulus, and interfacial strength of mineralized tissue to a higher degree. Titanium per se possesses an ability to alter cellular phenotypes and tissue micro- and ultrastructure that result in enhanced intrinsic biomechanical properties of mineralized tissue.
Assuntos
Calcificação Fisiológica/fisiologia , Osseointegração/fisiologia , Osteoblastos/citologia , Poliestirenos/química , Titânio/química , Animais , Fenômenos Biomecânicos , Osso e Ossos/química , Osso e Ossos/citologia , Osso e Ossos/fisiologia , Cálcio/metabolismo , Técnicas de Cultura de Células , Proliferação de Células , Colágeno/genética , Colágeno/metabolismo , Elasticidade , Microanálise por Sonda Eletrônica , Matriz Extracelular/ultraestrutura , Expressão Gênica/genética , Dureza , Masculino , Microscopia de Força Atômica , Microscopia Eletrônica de Varredura , Nanotecnologia , Osteoblastos/metabolismo , Próteses e Implantes , Ratos , Ratos Sprague-Dawley , Propriedades de SuperfícieRESUMO
The critical load determined by the scratch test is regarded to be a representative measure of coating adhesion in the field of engineering. This study aimed to evaluate the method for its usefulness for assessing the mineralized tissue-titanium interface strength. Osteoblastic cells derived from rat bone marrow were cultured on polystyrene, titanium-coated polystyrene, and titanium disks with either a machined or dual-acid etched surface. Nano-scratch testing was performed on mineralized tissue specimens at culture day 28. The scratch path was monitored by light microscopy until complete delamination of mineralized tissue from the substrate occurred, and the required force was recorded as the critical load. Energy-dispersive spectroscopic analysis was used to verify the delamination. The mean critical load values (+/- standard deviations) were as follows: polystyrene 31 mN (+/-1), titanium-coated polystyrene 67 mN (+/-4), machined titanium 76 mN (+/-4), DAE titanium 107 mN (+/-3), with statistical differences (P < 0.05; ANOVA). No elemental calcium and phosphorous were observed in the delaminated areas. The nano-scratch test applied to cultured mineralized tissue differentiated the critical load from various culture conditions: polystyrene vs. titanium; titanium with different surface topographies. Culturing mineralized tissue on titanium, especially on roughened surfaces, increased the tissue critical load. The nano-scratch test may be useful to evaluate mineralized tissue adhesion properties in titanium cultures.
Assuntos
Calcificação Fisiológica , Poliestirenos , Titânio , Animais , Células Cultivadas , Nanotecnologia , Osteoblastos/citologia , Ratos , Ratos Sprague-Dawley , Propriedades de SuperfícieRESUMO
The aim of this study was to examine the effect of NaOCl pretreatment on the biomechanical fixation of implant at the early healing stage of a rat model. Polished titanium cylindrical implants and disks were prepared, and one-half of these samples were dual acidetched. Then, one-half of both surfaces were chemically-cleaned by pretreatment with 5% NaOCl solution for 24 h. Morphological analyses showed that there was no significant difference between before and after NaOCl treatment. The wettability measurement demonstrated that NaOCl treatment secondarily converted both titanium surfaces from hydrophobic to superhydrophilic, accompanied by the removal of hydrocarbons from the titanium surfaces. Biomechanical push-in test indicated that the bone-titanium integration strength of the NaOCl-treated implants were significantly greater than that of the untreated implants (p<0.05). These results showed that NaOCl pretreatment enhanced the osseointegration capability of titanium, indicating its potential for a simple chemical chair-side pretreatment method.
Assuntos
Interface Osso-Implante , Materiais Dentários , Hipoclorito de Sódio/farmacologia , Titânio , Animais , Fenômenos Biomecânicos , Implantes Dentários , Osseointegração , Osteogênese , RatosRESUMO
This study examined the effect of photofunctionalization on bioactivity and osteoconductivity of titanium alloy Ti6Al4V. We also tested a hypothesis that the effect of photofunctionalization is as substantial as the one of surface roughening. Two different surface morphology, a roughened surface (sandblasted and acid-etched surface) and relatively smooth surface (machined surface), was tested. Ti6Al4V samples were photofunctionalized with UV light for 15 min using a photo device. Photofunctionalization converted Ti6Al4V surfaces from hydrophobic to superhydrophilic. The attachment, spread, proliferation, and the expression of functional phenotype of bone marrow-derived osteoblasts were promoted on photofunctionalized Ti6Al4V surfaces. The strength of bone-implant integration examined using a biomechanical push-in test in a rat femur model was at least 100% greater for photofunctionalized implants than for untreated implants. These effects were seen on both surface types. The strength of bone-implant integration for photofunctionalized machined implants was greater than that for untreated roughened implants, indicating that the impact of photofunctionalization may be greater than that of surface roughening. Newly prepared Ti alloy was hydrophilic, whereas the hydrophilic status degraded with time and was converted to hydrophobic in 4 weeks. This finding uncovered biological aging of Ti alloy and allowed us to consider photofunctionalization as a countermeasure for aging. These results suggest that photofunctionalization accelerates and enhances bone-implant integration of Ti6Al4V regardless of smooth and roughened surface features, supporting photofunctionalization as an effective and viable measure for improving efficacy of a wide range of Ti6Al4V-based materials used in dental and orthopedic medicine.
Assuntos
Regeneração Óssea/efeitos da radiação , Titânio/farmacologia , Titânio/efeitos da radiação , Raios Ultravioleta , Fosfatase Alcalina/metabolismo , Ligas , Animais , Cálcio/metabolismo , Adesão Celular/efeitos dos fármacos , Interações Hidrofóbicas e Hidrofílicas/efeitos dos fármacos , Implantes Experimentais , Masculino , Microscopia Eletrônica de Varredura , Osseointegração/efeitos dos fármacos , Osteoblastos/citologia , Osteoblastos/efeitos dos fármacos , Osteoblastos/enzimologia , Osteoblastos/efeitos da radiação , Fenótipo , Ratos Sprague-Dawley , Espectrometria por Raios X , Propriedades de Superfície , Fatores de TempoRESUMO
This position paper reviews physical and mechanical properties of thermoplastic resin used for non-metal clasp dentures, and describes feature of each thermoplastic resin in clinical application of non-metal clasp dentures and complications based on clinical experience of expert panels. Since products of thermoplastic resin have great variability in physical and mechanical properties, clinicians should utilize them with careful consideration of the specific properties of each product. In general, thermoplastic resin has lower color-stability and higher risk for fracture than polymethyl methacrylate. Additionally, the surface of thermoplastic resin becomes roughened more easily than polymethyl methacrylate. Studies related to material properties of thermoplastic resin, treatment efficacy and follow-up are insufficient to provide definitive conclusions at this time. Therefore, this position paper should be revised based on future studies and a clinical guideline should be provided.
Assuntos
Materiais Dentários , Prótese Parcial Removível , Resinas Sintéticas , Resinas Acrílicas , Humanos , Fenômenos Mecânicos , Metais , Nylons , Fenômenos Físicos , Cimento de Policarboxilato , Poliésteres , Polímeros , Polimetil Metacrilato , Polipropilenos , SulfonasRESUMO
This position paper proposes a definition and naming standard for removable partial dentures (RPDs) using thermoplastic resin, and presents a guideline for clinical application. A panel of 14 experts having broad experience with clinical application of RPDs using thermoplastic resin was selected from members of the Japan Prosthodontic Society. At a meeting of the panel, "non-metal clasp denture" was referred as the generic name of RPDs with retentive elements (resin clasps) made of thermoplastic resin. The panel classified non-metal clasp dentures into two types: one with a flexible structure that lacks a metal framework and the other having a rigid structure that includes a metal framework. According to current prosthetic principles, flexible non-metal clasp dentures are not recommended as definitive dentures, except for limited cases such as patients with a metal allergy. Rigid non-metal clasp dentures are recommended in cases where patients will not accept metal clasps for esthetic reasons. Non-metal clasp dentures should follow the same design principles as conventional RPDs using metal clasps.
Assuntos
Grampos Dentários , Planejamento de Dentadura , Prótese Parcial Removível , Resinas Sintéticas , Contraindicações , Retenção de Dentadura , Humanos , Metais/efeitos adversosRESUMO
Titanium surfaces with micro-nano hybrid topography (nanoscale nodules in microscale pits) have been recently demonstrated to show higher biological capability than those with microtopography alone. On the other hand, UV treatment of titanium surfaces, which is called UV photofunctionalization, has recently been introduced to substantially increase the biological capability and osteoconductivity of titanium surfaces. However, synergistic effects of these two advanced surface modification technologies and regulatory factors to potentially modulate the mutual effects have never been addressed. In this study, utilization of a recently discovered controllable self-assembly of TiO(2) nanonodules has enabled the exploration of the relative contribution of different sizes of nanostructures to determine the biological capability of titanium surfaces and their relative responsiveness to UV photofunctionalization. Rat bone marrow-derived osteoblasts were cultured on titanium disks with either micropits alone, micropits with 100-nm nodules, micropits with 300-nm nodules, or micropits with 500-nm nodules, with or without UV treatment. Although UV treatment increased the attachment, spread, proliferation, and mineralization of these cells on all titanium surfaces, these effects were more accentuated (3-5 times) on nanonodular surfaces than on surfaces with micropits alone and were disproportionate depending on nanonodule sizes. For instance, on UV-treated micro-nano hybrid surfaces, cell attachment correlated with nanonodule sizes in a quadratic approximation with its peak for 300-nm nodules followed by a decline for 500-nm nodules, while cell attachment exponentially correlated with surface roughness with its plateau achieved for 300-nm nodules without a subsequent decline. Moreover, cell attachment increased in a linear correlation with the surface area, while no significant effect of the inter-irregularities space or degree of hydrophilicity was observed on cell attachment. These results suggest that the effect of UV photofunctionalization can be multiplied on micro-nano hybrid titanium surfaces compared with the surfaces with micropits alone. This multiplication is disproportionately regulated by a selected set of topographical parameters of the titanium surfaces. Among the nanonodules tested in this study, 300-nm nodules seemed to create the most effective morphological environment for responding to UV photofunctionalization. The data provide a systematic platform to effectively optimize nanostructures on titanium surfaces in order to enhance their biological capability as well as their susceptibility to UV photofunctionalization.
Assuntos
Nanoestruturas/química , Fotoquímica/métodos , Titânio/química , Raios Ultravioleta , Animais , Células da Medula Óssea/citologia , Células da Medula Óssea/fisiologia , Masculino , Teste de Materiais , Nanoestruturas/ultraestrutura , Ratos , Ratos Sprague-Dawley , Propriedades de SuperfícieRESUMO
This study examines the cytotoxicity of bone cement extract to osteoblasts and the potential detoxification and restoration of osteoblastic function by an antioxidant amino acid, N-acetyl cysteine (NAC). The osteoblastic cells derived from rat femurs were cultured with extract from polymethyl methacrylate (PMMA)-based bone cement. The calcein and ethidium homodimer staining of the cells after 24-h incubation showed that 23.0% of the cells were dead in the culture with bone cement extract, while the addition of 5 mM NAC into the culture reduced the percentage to 4.3%. Annexin V and propidium iodide-based flow cytometric analysis also revealed that the apoptotic cells present at 15.8% in the culture with bone cement extract was reduced to 2.4% in the culture cotreated with bone cement extract and NAC. Severely suppressed alkaline phosphatase activity and matrix mineralization in the culture with bone cement extract (reduced to 10% and 5%, respectively, compared with the control culture) were restored to a normal level when treated with 5 mM NAC. The bone cement extract-induced, downregulated expression of osteoblastic genes, such as alkaline phosphatase, collagen I, and osteocalcin, was also restored to the baseline level by cotreatment with NAC. The data indicated that the addition of NAC into acrylic bone cement extract remarkably ameliorated the cytotoxicity to osteoblasts and restored their phenotype and function to a biologically significant degree, suggesting the potential usefulness of NAC in developing more biocompatible acrylic bone cement.
Assuntos
Acetilcisteína/farmacologia , Cimentos Ósseos/farmacologia , Osteoblastos/citologia , Osteoblastos/efeitos dos fármacos , Polimetil Metacrilato/farmacologia , Fosfatase Alcalina/metabolismo , Animais , Calcificação Fisiológica/efeitos dos fármacos , Caspases/metabolismo , Contagem de Células , Morte Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Regulação da Expressão Gênica/efeitos dos fármacos , Glutationa/metabolismo , Masculino , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Osteoblastos/enzimologia , Ratos , Ratos Sprague-Dawley , Transdução de Sinais/efeitos dos fármacosRESUMO
Titanium implants are used as a reconstructive anchor in orthopedic and dental diseases and problems. Recently, ultraviolet (UV) light-induced photocatalytic activity of titanium has earned considerable and broad interest in environmental and clean-energy sciences. This study determines whether UV treatment of titanium enhances its osteoconductive capacity. Machined and acid-etched titanium samples were treated with UV for various time periods up to 48h. For both surfaces, UV treatment increased the rates of attachment, spread, proliferation and differentiation of rat bone marrow-derived osteoblasts, as well as the capacity of protein adsorption, by up to threefold. In vivo histomorphometry in the rat model revealed that new bone formation occurred extensively on UV-treated implants with virtually no intervention by soft tissue, maximizing bone-implant contact up to nearly 100% at week 4 of healing. An implant biomechanical test revealed that UV treatment accelerated the establishment of implant fixation 4 times. The rates of protein adsorption and cell attachment strongly correlated with the UV dose-responsive atomic percentage of carbon on TiO2, but not with the hydrophilic status. The data indicated that UV light pretreatment of titanium substantially enhances its osteoconductive capacity, in association with UV-catalytic progressive removal of hydrocarbons from the TiO2 surface, suggesting a photofunctionalization of titanium enabling more rapid and complete establishment of bone-titanium integration.
Assuntos
Osseointegração/efeitos dos fármacos , Osseointegração/efeitos da radiação , Titânio/farmacologia , Titânio/efeitos da radiação , Raios Ultravioleta , Adsorção/efeitos dos fármacos , Adsorção/efeitos da radiação , Animais , Carbono , Bovinos , Adesão Celular/efeitos dos fármacos , Adesão Celular/efeitos da radiação , Movimento Celular/efeitos dos fármacos , Movimento Celular/efeitos da radiação , Proliferação de Células/efeitos dos fármacos , Proliferação de Células/efeitos da radiação , Relação Dose-Resposta à Radiação , Fibronectinas/metabolismo , Implantes Experimentais , Masculino , Osteoblastos/citologia , Osteoblastos/efeitos dos fármacos , Osteoblastos/efeitos da radiação , Osteogênese/efeitos dos fármacos , Osteogênese/efeitos da radiação , Fenótipo , Ratos , Ratos Sprague-Dawley , Soroalbumina Bovina/metabolismoRESUMO
Improving the osteoconductive potential of titanium implants has been of continuing interest in the fields of dentistry and orthopedic surgery. This study determined the bioactivity of ultraviolet (UV) light-treated titanium. Human mesenchymal stem cells (MSCs) were cultured on acid-etched microtopographical titanium surfaces with and without 48h pretreatment with UVA (peak wavelength of 360n m) or UVC (peak wavelength of 250 nm). The number of cells that migrated to the UVC-treated surface during the first 3h of incubation was eight times higher than those that migrated to the untreated surface. After 24h of incubation, the number of cells attached to the UVC-treated surface was over three times more than those attached to the untreated surface. On the UVC-treated surface, the cellular spread was expedited with an extensive and intensive expression of the focal adhesion protein vinculin. The cells on the UVC-treated surface exhibited a threefold higher bromodeoxyuridine incorporation, a doubling of the alkaline phosphatase-positive area and the up-regulated expression of bone-related genes, indicating the accelerated proliferation and differentiation. The UVC-treated surface did not adversely affect the viability of the cells. These biological effects were not seen after UVA treatment, despite the generation of superhydrophilicity. Thus, we discovered a novel photofunctionalization of titanium dioxide that substantially enhances its bioactivity in human MSCs. Further studies are required to investigate the universal effectiveness of this surface modification for different titanium-containing materials, with varying chemistries and textures, as well as to understand its significance in enhancing in vivo osteoconductivity.