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Sample records for all-ceramic dental restorations

  1. Adhesion of oral streptococci to all-ceramics dental restorative materials in vitro.

    PubMed

    Meier, R; Hauser-Gerspach, I; Lüthy, H; Meyer, J

    2008-10-01

    In recent years, patients have benefited from the development of better and more esthetic materials, including all-ceramics dental restorative materials. Dental plaque formation on teeth and restorative materials plays an important role in the pathogenesis of oral diseases. This study investigates initial adhesion of stationary phase streptococcal species to different all-ceramics dental restorative materials. The saliva-coated materials were incubated with the bacteria for 1 h in an in vitro flow chamber which mimics environmental conditions in the oral cavity. Number and vitality of adhering bacteria were determined microscopically after staining. Surface roughness and the composition of the materials had no distinctive influence on bacterial adhesion. However, S. mutans and S. sobrinus adhered about tenfold less numerous to all materials than the other streptococcal species. Further, there was a correlation between bacterial vitality and materials' glass content. The results showed that early plaque formation was influenced predominantly by the presence of the salivary pellicle rather than by material dependent parameters whereas the composition of the all-ceramics appeared to have influenced the percentage of viable cells during the adhesion process. This presented in vitro technique may provide a useful model to study the influence of different parameters on adherence of oral streptococcal species.

  2. Optimizing the design of bio-inspired functionally graded material (FGM) layer in all-ceramic dental restorations.

    PubMed

    Cui, Chang; Sun, Jian

    2014-01-01

    Due to elastic modulus mismatch between the different layers in all-ceramic dental restorations, high tensile stress concentrates at the interface between the ceramic core and cement. In natural tooth structure, stress concentration is reduced by the functionally graded structure of dentin-enamel junction (DEJ) which interconnects enamel and dentin. Inspired by DEJ, the aim of this study was to explore the optimum design of a bio-inspired functionally graded material (FGM) layer in all-ceramic dental restorations to achieve excellent stress reduction and distribution. Three-dimensional finite element model of a multi-layer structure was developed, which comprised bilayered ceramic, bio-inspired FGM layer, cement, and dentin. Finite element method and first-order optimization technique were used to realize the optimal bio-inspired FGM layer design. The bio-inspired FGM layer significantly reduced stress concentration at the interface between the crown and cement, and stresses were evenly distributed in FGM layer. With the optimal design, an elastic modulus distribution similar to that in DEJ occurred in the FGM layer.

  3. Advancements in all-ceramics for dental restorations and their effect on the wear of opposing dentition

    PubMed Central

    Rashid, Haroon; Sheikh, Zeeshan; Misbahuddin, Syed; Kazmi, Murtaza Raza; Qureshi, Sameer; Uddin, Muhammad Zuhaib

    2016-01-01

    Tooth wear is a process that is usually a result of tooth to tooth and/or tooth and restoration contact. The process of wear essentially becomes accelerated by the introduction of restorations inside the oral cavity, especially in case of opposing ceramic restorations. The newest materials have vastly contributed toward the interest in esthetic dental restorations and have been extensively studied in laboratories. However, despite the recent technological advancements, there has not been a valid in vivo method of evaluation involving clinical wear caused due to ceramics upon restored teeth and natural dentition. The aim of this paper is to review the latest advancements in all-ceramic materials, and their effect on the wear of opposing dentition. The descriptive review has been written after a thorough MEDLINE/PubMed search by the authors. It is imperative that clinicians are aware of recent advancements and that they should always consider the type of ceramic restorative materials used to maintain a stable occlusal relation. The ceramic restorations should be adequately finished and polished after the chair-side adjustment process of occlusal surfaces. PMID:28042280

  4. Techniques used to fabricate all-ceramic restorations in the dental practice.

    PubMed

    Puri, Sameer

    2005-07-01

    Porcelain is an increasingly popular material to use for restorations. This article will discuss the 3 main ways to fabricate porcelain restorations. The first method involves waxing up the restoration to the proper form and casting it in molten porcelain similar to the lost wax technique for gold. The second technique requires the use of porcelain in a powder form to be stacked on top of a refractory die or a platinum foil and then fired in the oven. The third main technique is the use of a CAD/CAM system to mill the porcelain restoration from a solid block of porcelain. All 3 techniques are valid and the clinician should have a thorough understanding of which techniques are appropriate in various clinical situations.

  5. Enhanced aesthetics with all ceramics restoration

    PubMed Central

    Nayar, Sanjna; Aruna, U.; Bhat, Wasim Manzoor

    2015-01-01

    The demand for the dentist to achieve excellence in esthetics and function has driven modern advances in materials and restoration fabrication. The development of various casting alloys and precise casting systems has contributed to the successful use of metal-based restorations. However, patient requests for more aesthetic and biologically “safe” materials that have led to an increased demand for metal-free restorations. The following case presentation illustrates a successful aesthetic and functional application of this exciting computer-aided design/computer-aided manufacturing-digital zirconia-based system for a natural smile. PMID:26015733

  6. Restoration of Endodontically Treated Molars Using All Ceramic Endocrowns

    PubMed Central

    Carlos, Roopak Bose; Thomas Nainan, Mohan; Pradhan, Shamina; Roshni Sharma; Benjamin, Shiny; Rose, Rajani

    2013-01-01

    Clinical success of endodontically treated posterior teeth is determined by the postendodontic restoration. Several options have been proposed to restore endodontically treated teeth. Endocrowns represent a conservative and esthetic restorative alternative to full coverage crowns. The preparation consists of a circular equigingival butt-joint margin and central retention cavity into the entire pulp chamber constructing both the crown and the core as a single unit. The case reports discussed here are moderately damaged endodontically treated molars restored using all ceramic endocrowns fabricated using two different systems, namely, CAD/CAM and pressed ceramic. PMID:24455318

  7. Fracture Rates and Lifetime Estimations of CAD/CAM All-ceramic Restorations.

    PubMed

    Belli, R; Petschelt, A; Hofner, B; Hajtó, J; Scherrer, S S; Lohbauer, U

    2016-01-01

    The gathering of clinical data on fractures of dental restorations through prospective clinical trials is a labor- and time-consuming enterprise. Here, we propose an unconventional approach for collecting large datasets, from which clinical information on indirect restorations can be retrospectively analyzed. The authors accessed the database of an industry-scale machining center in Germany and obtained information on 34,911 computer-aided design (CAD)/computer-aided manufacturing (CAM) all-ceramic posterior restorations. The fractures of bridges, crowns, onlays, and inlays fabricated from different all-ceramic systems over a period of 3.5 y were reported by dentists and entered in the database. Survival analyses and estimations of future life revealed differences in performance among ZrO2-based restorations and lithium disilicate and leucite-reinforced glass-ceramics.

  8. Recent Advances in Materials for All-Ceramic Restorations

    PubMed Central

    Griggs, Jason A.

    2010-01-01

    SYNOPSIS The past three years of research on materials for all-ceramic veneers, inlays, onlays, single-unit crowns, and multi-unit restorations are reviewed. The primary changes in the field were the proliferation of zirconia-based frameworks and computer-aided fabrication of prostheses, as well as, a trend toward more clinically relevant in vitro test methods. This report includes an overview of ceramic fabrication methods, suggestions for critical assessment of material property data, and a summary of clinical longevity for prostheses constructed of various materials. PMID:17586152

  9. Recent advances in materials for all-ceramic restorations.

    PubMed

    Griggs, Jason A

    2007-07-01

    The past 3 years of research on materials for all-ceramic veneers, inlays, onlays, single-unit crowns, and multi-unit restorations are reviewed in this article. The primary changes in the field were the proliferation of zirconia-based frameworks and computer-aided fabrication of prostheses, and a trend toward more clinically relevant in vitro test methods. This article includes an overview of ceramic fabrication methods, suggestions for critical assessment of material property data, and a summary of clinical longevity for prostheses constructed of various materials.

  10. Design for minimizing fracture risk of all-ceramic cantilever dental bridge.

    PubMed

    Zhang, Zhongpu; Zhou, Shiwei; Li, Eric; Li, Wei; Swain, Michael V; Li, Qing

    2015-01-01

    Minimization of the peak stresses and fracture incidence induced by mastication function is considered critical in design of all-ceramic dental restorations, especially for cantilever fixed partial dentures (FPDs). The focus of this study is on developing a mechanically-sound optimal design for all-ceramic cantilever dental bridge in a posterior region. The topology optimization procedure in association with Extended Finite Element Method (XFEM) is implemented here to search for the best possible distribution of porcelain and zirconia materials in the bridge structure. The designs with different volume fractions of zirconia are considered. The results show that this new methodology is capable of improving FPD design by minimizing incidence of crack in comparison with the initial design. Potentially, it provides dental technicians with a new design tool to develop mechanically sound cantilever fixed partial dentures for more complicated clinical situation.

  11. New nano-sized Al2O3-BN coating 3Y-TZP ceramic composites for CAD/CAM-produced all-ceramic dental restorations. Part I. Fabrication of powders.

    PubMed

    Yang, Se Fei; Yang, Li Qiang; Jin, Zhi Hao; Guo, Tian Wen; Wang, Lei; Liu, Hong Chen

    2009-06-01

    Partially sintered 3 mol % yttria-stabilized tetragonal zirconium dioxide (ZrO(2), zirconia) polycrystal (3Y-TZP) ceramics are used in dental posterior restorations with computer-aided design-computer-aided manufacturing (CAD/CAM) techniques. High strength is acquired after sintering, but shape distortion of preshaped compacts during their sintering is inevitable. The aim of this study is to fabricate new machinable ceramic composites with strong mechanical properties that are fit for all-ceramic dental restorations. Aluminum oxide (Al(2)O(3))-coated 3Y-TZP powders were first prepared by the heterogeneous precipitation method starting with 3Y-TZP, Al(NO(3))(3) . 9H(2)O, and ammonia, then amorphous boron nitride (BN) was produced and the as-received composite powders were coated via in situ reaction with boric acid and urea. Transmission electron microscopy (TEM) and X-ray diffraction (XRD) were used to analyze the status of Al(2)O(3)-BN on the surface of the 3Y-TZP particles. TEM micrographs show an abundance of Al(2)O(3) particles and amorphous BN appearing uniformly on the surface of the 3Y-TZP particles after the coating process. The size of the Al(2)O(3) particles is about 20 nm. The XRD pattern shows clearly the peak of amorphous BN among the peaks of ZrO(2).

  12. A comparison of all-ceramic restorative systems: Part 2.

    PubMed

    Giordano, R

    2000-01-01

    Overall, any of these systems can provide well-fitting, natural looking restorations as long as care is taken during the preparation and fabrication procedures. A key to successful use of all-ceramic materials is proper selection based on the clinical conditions involved in specific restorative procedures (see table). All systems have limitations on their use and when we try to stretch those limits, success rates may fall drastically. High stress areas should shift selection to high strength, clinically documented materials. Low stress areas requiring high translucency may be restored successfully using the lower strength castable glasses. Intermediate areas may shift selection to higher strength yet still translucent materials such as In-Ceram Spinell or Empress 2. Posterior regions might best be addressed with the use of In-Ceram Alumina or Procera. The case of posterior bridges would lock the selection into In-Ceram Zirconia. Finally, it is important for each of us to continually educate ourselves and to examine the evidence in order to make an informed decision and maximize clinical success.

  13. Topological design of all-ceramic dental bridges for enhancing fracture resistance.

    PubMed

    Zhang, Zhongpu; Chen, Junning; Li, Eric; Li, Wei; Swain, Michael; Li, Qing

    2016-06-01

    Layered all-ceramic systems have been increasingly adopted in major dental prostheses. However, ceramics are inherently brittle, and they often subject to premature failure under high occlusion forces especially in the posterior region. This study aimed to develop mechanically sound novel topological designs for all-ceramic dental bridges by minimizing the fracture incidence under given loading conditions. A bi-directional evolutionary structural optimization (BESO) technique is implemented within the extended finite element method (XFEM) framework. Extended finite element method allows modeling crack initiation and propagation inside all-ceramic restoration systems. Following this, BESO searches the optimum distribution of two different ceramic materials, namely porcelain and zirconia, for minimizing fracture incidence. A performance index, as per a ratio of peak tensile stress to material strength, is used as a design objective. In this study, the novel XFEM based BESO topology optimization significantly improved structural strength by minimizing performance index for suppressing fracture incidence in the structures. As expected, the fracture resistance and factor of safety of fixed partial dentures structure increased upon redistributing zirconia and porcelain in the optimal topological configuration. Dental CAD/CAM systems and the emerging 3D printing technology were commercially available to facilitate implementation of such a computational design, exhibiting considerable potential for clinical application in the future. Copyright © 2015 John Wiley & Sons, Ltd.

  14. The Importance of the Lifelike Esthetic Appearance of All-Ceramic Restorations on Anterior Teeth

    PubMed Central

    dos Santos, Daniela Micheline; Moreno, Amália; Vechiato-Filho, Aljomar José; Bonatto, Liliane da Rocha; Pesqueira, Aldiéris Alves; Laurindo Júnior, Murilo César Bento; de Medeiros, Rodrigo Antonio; da Silva, Emily Vivianne Freitas; Goiato, Marcelo Coelho

    2015-01-01

    The success of rehabilitation will not depend on just clinical procedures. A proper dental technique (ceramist) is required as well as the respect for some biomimetic principles to obtain the desired final result. This study has the purpose of describing a prosthetic rehabilitation with laminate veneers and all-ceramic crowns of a patient unsatisfied with a previous esthetic treatment because of the negligence of some biomimetic principles. A 45-year-old female patient was admitted to the dental clinic complaining about the lifelike appearance of her all-ceramic restorations. Before the fabrication of new restorations, a mock-up was conducted to verify the patient's satisfaction. A ceramist conducted all the fabrication process so that surface characterizations could be visually verified and the lifelike appearance of natural tooth could be reproduced. After the cementation procedure, the patient reported being satisfied with the lifelike appearance of the new restorations. Based on the clinical findings of the present case report, it can be concluded that the reproduction of the lifelike esthetic appearance of natural teeth and the visualization of the final results before definitive procedures are essential to obtain the clinical success. PMID:25705525

  15. Illuminating light-dependent color shifts in core and veneer layers of dental all-ceramics.

    PubMed

    Lee, Yong-Keun; Cha, Hyun-Suk; Yu, Bin

    2014-09-01

    The color of an object is perceived differently depending on the ambient light conditions. Since dental all-ceramic restorations are fabricated by building up several layers to reproduce the tooth shade, the optical properties of each layer should be optimized for successful shade reproduction. This study aimed to determine the separate contributions of the color shifts in each of the core and veneer layers of all-ceramics by switching the illuminating lights on the color shifts of layered ceramics. Specimens of seven kinds of core ceramics and the corresponding veneer ceramics for each core were fabricated with a layered thickness of 1.5 mm. A sintering ceramic was used as a reference core material. The Commission Internationale de l’Eclairage (CIE) color coordinates of core, veneer, and layered specimens were measured with a spectroradiometer under the CIE illuminant D65 (daylight), A (incandescent lamp), and F9 (fluorescent lamp) simulating lights. Color shifts of the layered specimens were primarily determined by the CIE a shifts (D65 to A switch) or by the CIE b shifts (D65 to F9 switch) of the veneer layer. The color coordinates shifts in the constituent layers differentially influenced those of the layered specimens by the kind of switched lights. Therefore, the optical properties of the constituent layers of all-ceramics should be controlled to reflect these findings.

  16. A new classification system for all-ceramic and ceramic-like restorative materials.

    PubMed

    Gracis, Stefano; Thompson, Van P; Ferencz, Jonathan L; Silva, Nelson R F A; Bonfante, Estevam A

    2015-01-01

    Classification systems for all-ceramic materials are useful for communication and educational purposes and warrant continuous revisions and updates to incorporate new materials. This article proposes a classification system for ceramic and ceramic-like restorative materials in an attempt to systematize and include a new class of materials. This new classification system categorizes ceramic restorative materials into three families: (1) glass-matrix ceramics, (2) polycrystalline ceramics, and (3) resin-matrix ceramics. Subfamilies are described in each group along with their composition, allowing for newly developed materials to be placed into the already existing main families. The criteria used to differentiate ceramic materials are based on the phase or phases present in their chemical composition. Thus, an all-ceramic material is classified according to whether a glass-matrix phase is present (glass-matrix ceramics) or absent (polycrystalline ceramics) or whether the material contains an organic matrix highly filled with ceramic particles (resin-matrix ceramics). Also presented are the manufacturers' clinical indications for the different materials and an overview of the different fabrication methods and whether they are used as framework materials or monolithic solutions. Current developments in ceramic materials not yet available to the dental market are discussed.

  17. Fracture resistance of teeth restored with all-ceramic inlays and onlays: an in vitro study.

    PubMed

    Saridag, S; Sevimay, M; Pekkan, G

    2013-01-01

    Fracture resistance of inlays and onlays may be influenced by the quantity of the dental structure removed and the restorative materials used. The purpose of this in vitro study was to evaluate the effects of two different cavity preparation designs and all-ceramic restorative materials on the fracture resistance of the tooth-restoration complex. Fifty mandibular third molar teeth were randomly divided into the following five groups: group 1: intact teeth (control); group 2: inlay preparations, lithium-disilicate glass-ceramic (IPS e.max Press, Ivoclar Vivadent AG, Schaan, Liechtenstein); group 3: inlay preparations, zirconia ceramic (ICE Zirkon, Zirkonzahn SRL, Gais, Italy); group 4: onlay preparations, lithium-disilicate glass-ceramic (IPS e.max Press); and group 5: onlay preparations, zirconia ceramic (ICE Zirkon). The inlay and onlay restorations were adhesively cemented with dual polymerizing resin cement (Variolink II, Ivoclar Vivadent AG). After thermal cycling (5° to 55°C × 5000 cycles), specimens were subjected to a compressive load until fracture at a crosshead speed of 0.5 mm/min. Statistical analyses were performed using one-way analysis of variance and Tukey HSD tests. The fracture strength values were significantly higher in the inlay group (2646.7 ± 360.4) restored with lithium-disilicate glass-ceramic than those of the onlay group (1673.6 ± 677) restored with lithium-disilicate glass-ceramic. The fracture strength values of teeth restored with inlays using zirconia ceramic (2849 ± 328) and onlays with zirconia ceramic (2796.3 ± 337.3) were similar to those of the intact teeth (2905.3 ± 398.8). In the IPS e.max Press groups, as the preparation amount was increased (from inlay to onlay preparation), the fracture resistance was decreased. In the ICE Zirkon ceramic groups, the preparation type did not affect the fracture resistance results.

  18. Addition of a pontic to all-ceramic Turkom-Cera fixed partial denture restorations

    PubMed Central

    Uludag, Bulent; Tokar, Emre; Polat, Serdar

    2013-01-01

    High-strength all-ceramic materials are commonly used in dentistry. When complications occur in an all-ceramic restoration, the restoration is usually replaced. This article describes the time-saving ability and cost-effectiveness of this novel technique for the addition of a pontic in two complicated clinical cases. Turkom-Cera™ [Turkom-Ceramic (M) Sdn. Bhd.] with aluminum oxide (99.98%) is an all-ceramic system that offers the option of addition of a new pontic to the sintered framework. The new pontic was cut off from an alumina blank [Turkom-Ceramic (M) Sdn. Bhd.], moistened, and attached to the framework using alumina gel [Turkom-Ceramic (M) Sdn. Bhd.]. The framework was veneered with veneering porcelain (Vita VM 7; VITA Zahnfabrik). The two cases presented here involving the addition of a pontic to sintered framework were followed up for at least 1 year. No complication was detected or reported by the patients. Alumina- and zirconia-based ceramics are particularly suitable for for all-ceramic restorations in high-stress bearing areas. However, replacement of a failed all-ceramic restoration is not the most practical solution, considering both cost and tooth-related factors. This attractive feature of the Turkom-Cera allows the repair of a fractured ceramic coping or the addition of a new pontic to restorations. PMID:24883033

  19. CAD/CAM fabricated single-unit all-ceramic post–core–crown restoration

    PubMed Central

    Vinothkumar, Thilla Sekar; Kandaswamy, Deivanayagam; Chanana, Pallavi

    2011-01-01

    This case report explains about an innovative treatment strategy for the management of damaged anterior teeth with reduced incisal clearance by means of a single-unit all-ceramic post–core–crown zirconia ceramic restoration fabricated by Computer-aided designing and computer-aided manufacturing (CAD/CAM) technology. The reinforced zirconia ceramics allow fabrication of durable esthetic restorations in cases with high functional loading and the unification of the post, core, and crown in a single unit decreases the frequency of failure by creating a monobloc effect. In addition, the use of CAD/CAM technology for designing and fabricating ceramic restorations offers the option of expeditiously preparing these high-strength all-ceramic restorations. PMID:21691515

  20. Bonding All-Ceramic Restorations with Two Resins Cement Techniques: A Clinical Report of Three-Year Follow-Up

    PubMed Central

    Anchieta, Rodolfo Bruniera; Rocha, Eduardo Passos; de Almeida, Erika Oliveira; Junior, Amilcar Chagas Freitas; Martini, Ana Paula

    2011-01-01

    Ceramics have been widely used for esthetic and functional improvements. The resin cement is the material of choice for bonding ceramics to dental substrate and it can also dictate the final esthetic appearance and strength of the restoration. The correct use of the wide spectrum of resin luting agents available depends on the dental tooth substrate. This article presents three-year clinical results of a 41 years old female patient B.H.C complaining about her unattractive smile. Two all-ceramic crowns and two laminates veneers were placed in the maxillary incisors and cemented with a self-adhesive resin luting cement and conventional resin luting cement, respectively. After a three-year follow-up, the restorations and cement/teeth interface were clinically perfect with no chipping, fractures or discoloration. Proper use of different resin luting cements shows clinical appropriate behavior after a three-year follow-up. Self-adhesive resin luting cement may be used for cementing all-ceramic crowns with high predictability of success, mainly if there is a large dentin surface available for bonding and no enamel at the finish line. Otherwise, conventional resin luting agent should be used for achieving an adequate bonding strength to enamel. PMID:21912505

  1. All-ceramic restorative system for esthetic implant-supported crowns: in vitro evaluations and clinical case report.

    PubMed

    Castellon, Paulino; Potiket, Narong; Soltys, James L; Johnson, James; Zavala, Julio

    2003-09-01

    Patient demands for improved esthetics have prompted the development of all-ceramic restorative systems for dental implants, but material strength and restorative costs have presented clinical challenges. Therefore, a new restorative system with tooth-shaped ceramic copings for the anterior and premolar jaw regions has been introduced to address these problems. Fatigue and 17o. compression tests were conducted in vitro to assess the mechanical strength of the 6 tooth-shaped copings and several luting agents of the system. A case report on the clinical use of the components is presented. All 6 tooth-shaped copings significantly exceeded the range of forces associated with restoration in the anterior jaw. Crown-endurance limits for fatigue and 17o. compression were 70% higher and 46% higher, respectively, than the established minimum-fatigue-endurance limits in those categories. In clinical evaluation, the ceramic restorative system performed well and produced excellent results; it has potential for implant restorations in the anterior and premolar regions of the jaw.

  2. Conservative restorative treatment using a single-visit, all-ceramic CAD/CAM system.

    PubMed

    Benk, Joel

    2007-01-01

    Computer-aided design/computer-aided manufacturing (CAD/CAM) continues to radically change the way in which the dental team plans, prepares, and fabricates a patient's restoration. This advancing technology offers the clinician the ability to scan the patient's failing dentition and then designs a long-lasting, reliable restoration based on this data. CAD/CAM systems also permit efficient, single-visit placement of the restoration while preserving much of the natural tooth structure. This article discusses how a chairside CAD/CAM system can be used to provide such a restoration in the posterior region in a single-visit.

  3. Influence of Interlayer Design on Residual Thermal Stresses in Trilayered and Graded All-Ceramic Restorations

    PubMed Central

    Henriques, Bruno; Fabris, Douglas; Souza, Júlio C. M.; Silva, Filipe S.; Mesquita-Guimarães, Joana; Zhang, Yu; Fredel, Márcio

    2017-01-01

    Residual thermal stresses are formed in dental restorations during cooling from high temperature processing. The aim of this study was to evaluate the influence of constructive design variables (composition and interlayer thickness) on residual stresses in alumina- and zirconia-graded restorations. Restorations' real-like cooling conditions were simulated using finite elements method and temperature-dependent material properties were used. Three different designs were evaluated: a bilayered restoration (sharp transition between materials); a trilayered restoration with a homogenous interlayer between core and veneer; and a trilayered restoration with a graded interlayer. The interlayer thickness and composition were varied. Zirconia restorations presented overall higher thermal stress values than alumina ones. Thermal stresses were significantly reduced by the presence of a homogeneous interlayer. The composition of the interlayer showed great influence on the thermal stresses, with the best results for homogeneous interlayers being observed for porcelain contents in the composite ranging between 30%-50% (vol.%), for both alumina and zirconia restorations. The interlayer's thickness showed a minor contribution in the thermal stress reduction. The graded interlayer showed an optimized reduction in restorations' thermal stresses. The use of graded interlayer, favoring enhanced thermal stress distributions and lower magnitude is expected to reduce the risk of catastrophic failure. PMID:27987657

  4. Load-bearing capacity of all-ceramic posterior inlay-retained fixed dental prostheses.

    PubMed

    Puschmann, Djamila; Wolfart, Stefan; Ludwig, Klaus; Kern, Matthias

    2009-06-01

    The purpose of this in vitro study was to compare the quasi-static load-bearing capacity of all-ceramic resin-bonded three-unit inlay-retained fixed dental prostheses (IRFDPs) made from computer-aided design/computer-aided manufacturing (CAD/CAM)-manufactured yttria-stabilized tetragonal zirconia polycrystals (Y-TZP) frameworks with two different connector dimensions, with and without fatigue loading. Twelve IRFDPs each were made with connector dimensions 3 x 3 mm(2) (width x height) (control group) and 3 x 2 mm(2) (test group). Inlay-retained fixed dental prostheses were adhesively cemented on identical metal-models using composite resin cement. Subgroups of six specimens each were fatigued with maximal 1,200,000 loading cycles in a chewing simulator with a weight load of 25 kg and a load frequency of 1.5 Hz. The load-bearing capacity was tested in a universal testing machine for IRFDPs without fatigue loading and for IRFDPs that had not already fractured during fatigue loading. During fatigue testing one IRFDP (17%) of the test group failed. Under both loading conditions, IRFDPs of the control group exhibited statistically significantly higher load-bearing capacities than the test group. Fatigue loading reduced the load-bearing capacity in both groups. Considering the maximum chewing forces in the molar region, it seems possible to use zirconia ceramic as a core material for IRFDPs with a minimum connector dimension of 9 mm(2). A further reduction of the connector dimensions to 6 mm(2) results in a significant reduction of the load-bearing capacity.

  5. Esthetic restoration of infra-occluded retained primary mandibular incisors with all-ceramic crowns in adult dentition.

    PubMed

    Hsu, Kuang-Wei; Shen, Yu-Fu

    2004-12-01

    The prevalence of hypodontia is reported to be between 1.5% to 10% in the permanent dentition. In the anterior teeth, maxillary lateral incisors and mandibular central incisors are the most frequently involved teeth. This causes esthetic problems for the patient. Several reports have focused on restoration of retained maxillary primary anterior teeth, but none have described restoration of retained mandibular primary incisors. This clinical report describes the restoration of infra-occluded retained primary mandibular central incisors of a 17 year-old girl diagnosed with hypodontia. All-ceramic crowns made with computer-aided design/ computer-aided manufacturing technology were used to restore the teeth incisally and interproximally. Due to a relatively short root length and inadequate crown-root ratio, the primary mandibular central incisors were splinted and adjusted to distribute the protrusive force evenly across the maxillary and mandibular incisors. Functional and esthetic results were achieved.

  6. Evaluation of the color reproducibility of all-ceramic restorations fabricated by the digital veneering method

    PubMed Central

    Kim, Jae-Hong; Kim, Ki-Baek; Kim, Woong-Chul; Kim, Hae-Young

    2014-01-01

    PURPOSE The objective of this study was to evaluate the clinical acceptability of all-ceramic crowns fabricated by the digital veneering method vis-à-vis the traditional method. MATERIALS AND METHODS Zirconia specimens manufactures by two different manufacturing method, conventional vs digital veneering, with three different thickness (0.3 mm, 0.5 mm, 0.7 mm) were prepared for analysis. Color measurement was performed using a spectrophotometer for the prepared specimens. The differences in shade in relation to the build-up method were calculated by quantifying ΔE* (mean color difference), with the use of color difference equations representing the distance from the measured values L*, a*, and b*, to the three-dimensional space of two colors. Two-way analysis of variance (ANOVA) combined with a Tukey multiple-range test was used to analyze the data (α=0.05). RESULTS In comparing means and standard deviations of L*, a*, and b* color values there was no significant difference by the manufacturing method and zirconia core thickness according to a two-way ANOVA. The color differences between two manufacturing methods were in a clinically acceptable range less than or equal to 3.7 in all the specimens. CONCLUSION Based on the results of this study, a carefully consideration is necessary while selecting upper porcelain materials, even if it is performed on a small scale. However, because the color reproducibility of the digital veneering system was within the clinically acceptable range when comparing with conventional layering system, it was possible to estimate the possibility of successful aesthetic prostheses in the latest technology. PMID:24843390

  7. [All-ceramic restorations in the esthetic zone--the problem of choice].

    PubMed

    Devigus, Alessandro

    2011-01-01

    The restoration of anterior teeth even for the experienced practitioner remains a challenge. Although there are different full-ceramic materials available on the market, the reproduction of optical properties in natural teeth is not easy at all. In this article, the author presents a simplified classification of teeth to be restored, in relation to the optical properties of actual ceramic systems, which helps to make the natural reproduction more predictable. For the dentist it's important to know about the optical properties of the teeth to be restored and the ceramic material used. Without this, the clinical success of restorations in the anterior segment of may not be predictable at all. For implant retained-and bridge-work there are additional parameters that need to be taken into consideration which are not addressed in this article. Ceramic materials with a high light transmission allow, in combination with adhesive bonding, the fabrication of esthetic restorations. High strength ceramics block the light more and therefore are not indicated for this type of reconstruction. They may be used to mask discolored substructures. The communication between dentist and lab technician plays an important role to be clinically successful.

  8. Fracture resistance of endodontically treated canines restored with different sizes of fiber post and all-ceramic crowns

    PubMed Central

    Alkumru, Hasan Necdet; Akalin, Buket

    2016-01-01

    PURPOSE The aim of this study was to determine the fracture resistance and the mode of fracture of endodontically treated teeth restored with different fiber posts and all-ceramic crowns. MATERIALS AND METHODS Two glass fiber reinforced post systems in two different sizes and polyethylene fiber ribbon in two different thicknesses (n=10) were used. The specimens, restored with all-ceramic crowns, were subjected to a compressive load (in N) delivered at a 130-degree angle to the long axis until a fracture could be noted. The results were analyzed statistically with a One-Way ANOVA test (P<.05). RESULTS Statistically significant differences were observed between the mean fracture resistance values of Postec, Snowlight, and Kerr Connect thin specimens (P<.0095). The Postec results (395.70 N) were found to be significantly higher than the others. No statistical difference was observed among the thick specimens (P<.2657). The mean fracture resistance values of the Snowlight thick samples were found to be higher than those of the Snowlight thin samples. The specimens were always fractured around the cemento-enamel junction at the palatinal side. No post fracture was observed for the thin Snowlight and Kerr Connect specimens or for the thick Postec and Kerr Connect specimens. Among the common failure types of the specimens, the worst was observed to be the root fracture failure. The highest post dislodgement failure result (80%) was obtained from the thin Kerr Connect specimen. CONCLUSION In terms of optimizing fracture resistance, the fiber post size selection should be done according to the forces applied to the restored teeth. PMID:27141261

  9. Longevity of Single-Tooth All-Ceramic CAD/CAM Restorations: A Meta-Analysis

    DTIC Science & Technology

    2013-07-01

    12     system. The cost of this system is approximately $116,000. The iTero system incorporates both a laser and a light emitting diode (LED...Altschuler, B. (1977). Laser holography in dentistry . Journal of Prosthetic Dentistry , 38 (2), 216-225. Zimmer S, Gohlich O, Ruttermann S, Lang H, Raab W...A thesis submitted to the Faculty of the Comprehensive Dentistry Graduate Program Naval Postgraduate Dental School Uniformed Services

  10. Standards of teeth preparations for anterior resin bonded all-ceramic crowns in private dental practice in Jordan

    PubMed Central

    AL-DWAIRI, Ziad Nawaf; AL-HIYASAT, Ahmad Saleh; ABOUD, Haitham

    2011-01-01

    Objectives To investigate if general dental practitioners (GDPs) in private practice in Jordan follow universal guidelines for preparation of anterior teeth for resin bonded all-ceramic crowns (RBCs). Material and Methods A sample (n=100) of laboratory models containing 208 tooth preparations for IPS Empress and In Ceram, featuring work from different GDPs, was obtained from 8 commercial dental laboratories. Aspects of preparations were quantified and compared with accepted criteria defined following a review of the literature and recommendations of the manufactures' guidelines. Results Subgingival margins on the buccal aspect were noticed in 36% of the preparations, 54% demonstrated overpreparation with a tendency to overprepare the teeth on the mesiodistal plane more than buccolingual plane. Twenty percent of samples presented a shoulder finish line while a chamfer margin design was noticed in 39%. Twenty-nine percent and 12% of samples had either a feathered or no clear margin design respectively. Incisal under preparation was observed in 18% of dies of each type. Only 17% of all preparations were found to follow the recommended anatomical labial preparations while 29% of the RBC preparations were found to have the recommended axial convergence angle. In total, 43% of preparations were found to have the recommended depth of the finish line. Conclusions It was found that relevant guidelines for RBC preparations were not being fully adhered to in private practice in Jordan. PMID:21710098

  11. Effect of abutment shade, ceramic thickness, and coping type on the final shade of zirconia all-ceramic restorations: in vitro study of color masking ability

    PubMed Central

    Oh, Seon-Hee

    2015-01-01

    PURPOSE The aim of the study was to evaluate the effect of abutment shade, ceramic thickness, and coping type on the final shade of zirconia all-ceramic restorations. MATERIALS AND METHODS Three different types of disk-shaped zirconia coping specimens (Lava, Cercon, Zirkonzahn: ø10 mm × 0.4 mm) were fabricated and veneered with IPS e.max Press Ceram (shade A2), for total thicknesses of 1 and 1.5 mm. A total of sixty zirconia restoration specimens were divided into six groups based on their coping types and thicknesses. The abutment specimens (ø10 mm × 7 mm) were prepared with gold alloy, base metal (nickel-chromium) alloy, and four different shades (A1, A2, A3, A4) of composite resins. The average L*, a*, b* values of the zirconia specimens on the six abutment specimens were measured with a dental colorimeter, and the statistical significance in the effects of three variables was analyzed by using repeated measures analysis of variance (α=.05).The average shade difference (ΔE) values of the zirconia specimens between the A2 composite resin abutment and other abutments were also evaluated. RESULTS The effects of zirconia specimen thickness (P<.001), abutment shade (P<.001), and type of zirconia copings (P<.003) on the final shade of the zirconia restorations were significant. The average ΔE value of Lava specimens (1 mm) between the A2 composite resin and gold alloy abutments was higher (close to the acceptability threshold of 5.5 ΔE) than th ose between the A2 composite resin and other abutments. CONCLUSION This in-vitro study demonstrated that abutment shade, ceramic thickness, and coping type affected the resulting shade of zirconia restorations. PMID:26576252

  12. All-ceramic crowns.

    PubMed

    Lehner, C R; Schärer, P

    1992-06-01

    Despite the good appearance and biocompatibility of dental porcelains, failures are still of considerable concern because of some limited properties common to all-ceramic crown systems. As in the years before, pertinent scientific articles published between November 1990 and December 1991 focused on strengthening mechanisms and compared fracture toughness for different ceramic systems by using various test methods. Some evaluated the clinical implications thereon for seating and loading crowns and measured wear against different ceramic surface conditions. Recently introduced with pleasing aesthetic qualities, IPS-Empress (Ivoclar, Schaan, Liechtenstein), a new European leucite-reinforced glass-ceramic, has finally drawn attention in some journals and has been reviewed with promising in vitro test results. Using a simple press-molding technique, well-fitting crowns, inlays, and veneers can be fabricated without an additional ceramming procedure. Again, only long-term clinical trials will validate achievements compared with other all-ceramic systems and with well-established metal ceramics.

  13. Prospective clinical split-mouth study of pressed and CAD/CAM all-ceramic partial-coverage restorations: 7-year results.

    PubMed

    Guess, Petra C; Selz, Christian F; Steinhart, Yann-Niclas; Stampf, Susanne; Strub, Joerg R

    2013-01-01

    The aim of this prospective clinical split-mouth study was to investigate the longterm performance of pressed and computer-aided design/computer-assisted manufacture (CAD/CAM) all-ceramic partial-coverage restorations (PCRs). Twentyfive patients were restored with 40 lithium disilicate pressed PCRs (IPS e.max-Press, Ivoclar Vivadent) and 40 leucite-reinforced glass-ceramic CAD/CAM PCRs (ProCAD, Ivoclar Vivadent). All restorations were placed in vital first or second molars. The 7-year Kaplan-Meier survival rate was 100% for pressed PCRs and 97% for CAD/ CAM PCRs. Both systems showed significant deterioration over time in all modified United States Public Health Service criteria. Increased surface roughness and impaired color match were significantly more prevalent with pressed PCRs. Based on the 7-year data, both all-ceramic systems can be considered reliable treatment options for posterior PCRs.

  14. Influence of sodalite zeolite infiltration on the coefficient of thermal expansion and bond strength of all-ceramic dental prostheses.

    PubMed

    Naji, Ghassan Abdul-Hamid; Omar, Ros Anita; Yahya, Rosiyah

    2017-03-01

    In all-ceramic systems, a high incidence of veneer chip-off has been reported in clinical studies. Coefficient of thermal expansion (CTE) behaviour is one of the factors that may increase residual stress in the interface and influence the veneer/core bond strength. Therefore, this study aimed to evaluate the effect of sodalite zeolite-infiltration on the CTE behaviour and bond strength of different all-ceramic prostheses. The case-study groups were synthesized sodalite zeolite-infiltrated alumina (IA-SOD) and synthesized sodalite zeolite-infiltrated zirconia-toughened alumina (ZTA) (IZ-SOD), while the control groups were glass-infiltrated alumina (IA-glass) and glass-infiltrated ZTA (IZ-glass). Forty cylindrical-shaped samples measuring 5 mm in diameter and 10 mm in height were tested for CTE using a thermo-mechanical analyser machine, and forty disc-shaped ceramic samples measuring 12 mm in diameter and 1.2 ± 0.2 mm in thickness were prepared using specially designed stainless steel split mould and veneered by cylinder-shaped (2 mm high × 2 mm diameter) low-fusing porcelain (Vita VM7). The veneer/core samples were sintered and tested for shear bond strength using a high precision universal testing machine. Scanning electron microscope, stereo microscope, atomic force microscope, and energy-dispersive X-ray spectroscopy were used to investigate the structural characteristics of samples at the fracture surface. The collected data were analyzed with a one-way ANOVA and Tukey HSD test (α=.05). IZ-SOD revealed highest CTE and shear bond strength values, while the IA-glass revealed the lowest values than the other groups. There was no significant difference in CTE and bond strength among IZ-SOD, IA-SOD and IZ-glass samples (p>0.05). The experimental SOD zeolite-infiltrated samples revealed higher CTE mismatch and bond strength along with a more favourable mode of failure than did the commercial glass-infiltrated samples. Sandblast technique is considered as effective

  15. A novel method for creating endodontic access preparations through all-ceramic restorations: air abrasion and its effect relative to diamond and carbide bur use.

    PubMed

    Sabourin, Christopher R; Flinn, Brian D; Pitts, David L; Gatten, Timothy L; Johnson, James D

    2005-08-01

    Access through porcelain restorations is a technically delicate and stressful procedure. Although this is a common dilemma in endodontics, little research has explored alternatives in cutting through porcelain. The purpose of this study was to compare the use of a carbide bur plus water, diamond bur plus water, and air abrasion to access through porcelain. All-ceramic samples were accessed using the different techniques. Samples were evaluated using two transillumination methods, white light, and fluorescent liquid penetrant described by the American Society for Testing and Materials. Edge chipping, microcracking, and catastrophic fracture of porcelain caused by the techniques were statistically compared. Fluorescent liquid penetrant was a more sensitive method for microcrack detection. There were significant differences between the preparation techniques. Air abrasion was significantly less destructive, and caused no catastrophic fractures, edge chipping or microcracks. Preparation by air abrasion took longer to complete.

  16. In Vitro Effect of Porcelain Firing Cycle and Different Thicknesses of IPS E.max CAD Core on Marginal Accuracy of All-Ceramic Restorations

    PubMed Central

    Jalalian, Ezatollah; Zarbakhsh, Arash; Mohtashamrad, Zahra; Nourbakhsh, Nazanin; Jafarpour, Esmat

    2015-01-01

    Objectives: Marginal adaptation is important for long-term success of full-coverage restorations. The aim of this study was to determine the effect of porcelain firing cycle and different thicknesses of IPS e.max core on marginal accuracy of all-ceramic restorations. Materials and Methods: A standard stainless steel die with 0.8 mm classic chamfer finish line and 10° taper was used in this in vitro study. An impression was taken from the stainless steel die to fabricate 20 epoxy resin dies, which were then scanned and IPS e.max CAD cores were fabricated using computer-aided design/computer-aided manufacturing (CAD/CAM) technique in two groups of 10 with 0.7 mm (group A) and 0.4mm (group B) core thickness. Copings were then placed on their respective dies and randomly numbered. The amount of marginal gap was measured in 10 points under a stereomicroscope (×90 magnification) before and after porcelain veneering. Results: The mean gap in 0.7mm and 0.4mm core thicknesses was 15.62±2.55μm and 19.68±3.09μm before porcelain firing and 32.01±3.19μm and 35.24±3.8μm after porcelain firing. The difference in marginal gap between the two thicknesses was significant before porcelain firing but not significant after veneering. Significant differences were also found in the marginal gap before and after porcelain veneering in each group. Conclusion: The porcelain firing cycle increases marginal gap in IPS e.max CAD restorations; 0.3 mm decrease in core thickness slightly increased marginal discrepancy, however it was not significant. PMID:27507992

  17. Contemporary all-ceramic materials, part-1.

    PubMed

    Pilathadka, Shriharsha; Vahalova, Dagmar

    2007-01-01

    Over the past 35 years, multiple types of all-ceramic materials have been introduced as an ideal alternative for metal-fused to ceramic. This review covers state-of-the-art development of all-ceramic systems in terms of history, material composition, fabrication technologies, and structural and strength properties. These materials are proved to be ideal in terms of mechanical properties and biocompatibility, making metal-free ceramic restorations a realistic clinical alternative for conventional metal-fused-to ceramic.

  18. Fractographic features of glass-ceramic and zirconia-based dental restorations fractured during clinical function.

    PubMed

    Oilo, Marit; Hardang, Anne D; Ulsund, Amanda H; Gjerdet, Nils R

    2014-06-01

    Fractures during clinical function have been reported as the major concern associated with all-ceramic dental restorations. The aim of this study was to analyze the fracture features of glass-ceramic and zirconia-based restorations fractured during clinical use. Twenty-seven crowns and onlays were supplied by dentists and dental technicians with information about type of cement and time in function, if available. Fourteen lithium disilicate glass-ceramic restorations and 13 zirconia-based restorations were retrieved and analyzed. Fractographic features were examined using optical microscopy to determine crack initiation and crack propagation of the restorations. The material comprised fractured restorations from one canine, 10 incisors, four premolars, and 11 molars. One crown was not categorized because of difficulty in orientation of the fragments. The results revealed that all core and veneer fractures initiated in the cervical margin and usually from the approximal area close to the most coronally placed curvature of the margin. Three cases of occlusal chipping were found. The margin of dental all-ceramic single-tooth restorations was the area of fracture origin. The fracture features were similar for zirconia, glass-ceramic, and alumina single-tooth restorations. Design features seem to be of great importance for fracture initiation.

  19. Fractographic features of glass-ceramic and zirconia-based dental restorations fractured during clinical function

    PubMed Central

    Øilo, Marit; Hardang, Anne D; Ulsund, Amanda H; Gjerdet, Nils R

    2014-01-01

    Fractures during clinical function have been reported as the major concern associated with all-ceramic dental restorations. The aim of this study was to analyze the fracture features of glass-ceramic and zirconia-based restorations fractured during clinical use. Twenty-seven crowns and onlays were supplied by dentists and dental technicians with information about type of cement and time in function, if available. Fourteen lithium disilicate glass-ceramic restorations and 13 zirconia-based restorations were retrieved and analyzed. Fractographic features were examined using optical microscopy to determine crack initiation and crack propagation of the restorations. The material comprised fractured restorations from one canine, 10 incisors, four premolars, and 11 molars. One crown was not categorized because of difficulty in orientation of the fragments. The results revealed that all core and veneer fractures initiated in the cervical margin and usually from the approximal area close to the most coronally placed curvature of the margin. Three cases of occlusal chipping were found. The margin of dental all-ceramic single-tooth restorations was the area of fracture origin. The fracture features were similar for zirconia, glass-ceramic, and alumina single-tooth restorations. Design features seem to be of great importance for fracture initiation. PMID:24698173

  20. CAD/CAM generated all-ceramic primary telescopic prostheses.

    PubMed

    Kurbad, A; Ganz, S; Kurbad, S

    2012-01-01

    Computer-aided design and manufacturing (CAD/CAM) systems have proven effective not only for the manufacture of crown and bridge frameworks, inlays, onlays and veneers, but also for the generation of all-ceramic primary telescopic prostheses in more than 10 years of use in dental technology. The new InLab 4.0 software generation makes it possible to design and mill primary telescopic prostheses with CAD/CAM technology. The computer-generated raw crowns for these restorations require very little manual adaptation. The secondary crowns are manufactured by electroforming and bonded onto the tertiary structure or framework.

  1. Ceramics as biomaterials for dental restoration.

    PubMed

    Höland, Wolfram; Schweiger, Marcel; Watzke, Ronny; Peschke, Arnd; Kappert, Heinrich

    2008-11-01

    Sintered ceramics and glass-ceramics are widely used as biomaterials for dental restoration, especially as dental inlays, onlays, veneers, crowns or bridges. Biomaterials were developed either to veneer metal frameworks or to produce metal-free dental restorations. Different types of glass-ceramics and ceramics are available and necessary today to fulfill customers' needs (patients, dentists and dental technicians) regarding the properties of the biomaterials and the processing of the products. All of these different types of biomaterials already cover the entire range of indications of dental restorations. Today, patients are increasingly interested in metal-free restoration. Glass-ceramics are particularly suitable for fabricating inlays, crowns and small bridges, as these materials achieve very strong, esthetic results. High-strength ceramics are preferred in situations where the material is exposed to high masticatory forces.

  2. Costing dental restorations in public sector dental clinics.

    PubMed

    Khairiyah, Abdul Muttalib; Razak, Ishak Abdul; Raja-Latifah, Raja Jalludin; Tan, Bee Siew; Norain, Abu Talib; Noor-Aliyah, Ismail; Natifah, Che Salleh; Rauzi, Ismail

    2009-04-01

    The objective of this study is to share cost analysis methodology and to obtain cost estimates for posterior restorations in public sector dental clinics. Two urban and 2 rural dental clinics in Selangor state were selected. Only cases of 1 posterior restoration per visit by dental officers were included over 6 months. One capsulated amalgam type, 1 capsulated tooth-colored, and 1 non-capsulated tooth-colored material were selected. A clinical pathway form was formulated to collect data per patient. Annual capital and recurrent expenditures were collected per clinic. The mean cost of an amalgam restoration was RM 30.96 (sdRM 7.86); and tooth-colored restorations ranged from RM 33.00 (sdRM 8.43) to RM 41.10 (sdRM 10.61). Wherein 1 USD = RM 2.8. Restoration costs were 35% to 55% higher in clinics in rural areas than in urban areas. The findings demonstrate economy of scale for clinic operation and restoration costs with higher patient load. Costs per restoration were higher in rural than in urban dental clinics. More studies are recommended to address the dearth of dental costs data in Malaysia.

  3. [Prosthetic rehabilitation of partially edentulous patients: fixed - removable - combined? Metal - ceramics - all - ceramics? Implants? Anything goes! Part 1: two example cases of a combined fixed-removable restoration].

    PubMed

    Schnabl, Dagmar

    2015-01-01

    After a careful diagnosis, treatment planning and pretreatment, two partially edentulous patients were restored partly by onlays, crowns and bridges, partly by removable prostheses. According to esthetic and functional demands all- and/or metal-ceramic restorations were used as well as cast frame prostheses with clasps or extracoronal attachments.

  4. Low-shrink monomers for dental restorations.

    PubMed

    Palin, W M; Fleming, G J P

    2003-04-01

    The main disadvantages of resin-based composites (RBCs) for use in load-bearing posterior restorations include the polymerization shrinkage following curing and inadequate wear resistance in service. These properties are largely influenced by the monomer system and research is currently being undertaken to decrease polymerization shrinkage and improve resin wear characteristics in an attempt to increase RBC restoration longevity. The scope of the current review will identify the development of resin-based restoratives, indicating the reported advantages and disadvantages of resin types routinely used in dental practice today and review the most recent advancements in resin technology.

  5. Direct Tensile Strength and Characteristics of Dentin Restored with All-Ceramic, Resin-Composite, and Cast Metal Prostheses Cemented with Resin Adhesives

    PubMed Central

    Piemjai, Morakot; Nakabayashi, Nobuo

    2015-01-01

    A dentin-cement-prosthesis complex restored with either all-porcelain, cured resin-composite, or cast base metal alloy and cemented with either of the different resin cements was trimmed into a mini-dumbbell shape for tensile testing. The fractured surfaces and characterization of the dentin-cement interface of bonded specimens were investigated using a Scanning Electron Microscope. A significantly higher tensile strength of all-porcelain (12.5 ± 2.2 MPa) than that of cast metal (9.2 ± 3.5 MPa) restorations was revealed with cohesive failure in the cement and failure at the prosthesis-cement interface in Super-Bond C&B group. No significant difference in tensile strength was found among the types of restorations using the other three cements with adhesive failure on the dentin side and cohesive failure in the cured resin. SEM micrographs demonstrated the consistent hybridized dentin in Super-Bond C&B specimens that could resist degradation when immersed in hydrochloric acid followed by NaOCl solutions whereas a detached and degraded interfacial layer was found for the other cements. The results suggest that when complete hybridization of resin into dentin occurs tensile strength at the dentin-cement is higher than at the cement-prosthesis interfaces. The impermeable hybridized dentin can protect the underlying dentin and pulp from acid demineralization, even if detachment of the prosthesis has occurred. PMID:26539520

  6. Information system analysis of an e-learning system used for dental restorations simulation.

    PubMed

    Bogdan, Crenguţa M; Popovici, Dorin M

    2012-09-01

    The goal of using virtual and augmented reality technologies in therapeutic interventions simulation, in the fixed prosthodontics (VirDenT) project, is to increase the quality of the educational process in dental faculties, by assisting students in learning how to prepare teeth for all-ceramic restorations. Its main component is an e-learning virtual reality-based software system that will be used for the developing skills in grinding teeth, needed in all-ceramic restorations. The complexity of the domain problem that the software system dealt with made the analysis of the information system supported by VirDenT necessary. The analysis contains the following activities: identification and classification of the system stakeholders, description of the business processes, formulation of the business rules, and modelling of business objects. During this stage, we constructed the context diagram, the business use case diagram, the activity diagrams and the class diagram of the domain model. These models are useful for the further development of the software system that implements the VirDenT information system.

  7. Interactions of liposomes with dental restorative materials.

    PubMed

    Nguyen, Sanko; Adamczak, Malgorzata; Hiorth, Marianne; Smistad, Gro; Kopperud, Hilde Molvig

    2015-12-01

    The in vitro adsorption and retention of liposomes onto four common types of dental restorative materials (conventional and silorane-based resin composites as well as conventional and resin-modified glass ionomer cements (GIC)) have been investigated due to their potential use in the oral cavity. Uncoated liposomes (positively and negatively charged) and pectin (low- and high-methoxylated) coated liposomes were prepared and characterized in terms of particle size and zeta potential. The adsorption of liposomes was performed by immersion, quantified by fluorescence detection, and visualized by fluorescence imaging and atomic force microscopy. Positive liposomes demonstrated the highest adsorption on all four types of materials likely due to their attractive surface charge. They also retained well (minimum 40% after 60 min) on both conventional resin composite and GIC even when exposed to simulated salivary flow. Although an intermediate initial level of adsorption was found for the pectin coated liposomes, at least 70% high methoxylated-pectin coated liposomes still remained on the conventional resin composite after 60 min flow exposure. This indicates significant contribution of hydrophobic interactions in the prolonged binding of liposomes to resin composites. Based on these results, the present paper suggests two new possible applications of liposomes in the preservation of dental restorations.

  8. [Prosthetic rehabilitation of partially edentulous patients: fixed - removable - combined? Metal - ceramics - all - ceramics? Implants? Anything goes! Part 2: two case studies represent the fixed, respectively the combined fixed-removable prosthetic restoration by utilization of implants].

    PubMed

    Schnabl, Dagmar

    2015-01-01

    The prosthetic rehabilitation of two partially edentulous patients is presented: one Patient was restored by permanent crowns and bridges attached to natural teeth and to implants, the second was treated by crowns attached to natural teeth and removable implant- supported prostheses. Depending on esthetic requirements and the localization of preparation margins all- or metal-ceramics were used for single crowns, metal-ceramics was used for bridges. In general, a well coordinated cooperation of dentist, surgeon and dental technician in treatment planning and realization is required for a successful prosthetic rehabilitation.

  9. Fracture toughness of dental restorative materials.

    PubMed

    Ilie, Nicoleta; Hickel, Reinhard; Valceanu, Anca Silvia; Huth, Karin Christine

    2012-04-01

    The ability of a restorative material to withstand fracture is of crucial importance especially in stress-bearing area. Therefore, the study aims to analyse the fracture toughness of a large number of dental restorative materials categories. The fracture toughness (K(IC)) of 69 restorative materials belonging to ten materials categories-micro-hybrid, nanofilled, microfilled, packable, ormocer-based, and flowable resin-based composites (RBC), compomers and flowable compomers, as well as glass ionomer cements (GIC) and resin-modified GIC was measured by means of the single-edge notched-beam method after storing the samples (n = 8) for 24 h in distilled water. Data were analyzed with the one-way analysis of variance (ANOVA) followed by the Tukey's test and partial eta-squared statistics (p < 0.05). Large variations between the tested materials within a material category were found. The lowest fracture toughness was reached in the GIC group, followed by the microfilled RBCs, resin-modified GIC, and flowable compomers, which do not differ significantly among each other as a material group. The ormocer-based, packable, and micro-hybrid RBCs performed statistically similar, reaching the highest fracture toughness values. Between the two categories of flowables-composites and compomers-no differences were measured. The correlation between K(IC) and filler volume (0.34) and respective filler weight (0.40) was low. K(IC) increased with the volume fraction of fillers until a critical value of 57%, following with a plateau, with constant values until ca. 65% volume fraction. Above this value, K(IC) decreased slightly. Due to the very large variability of the fracture toughness within a material type, the selection of a suitable restorative material should have not been done with respect to a specific material category, especially in stress-bearing areas, but by considering the individual measured material properties.

  10. Anterior all-ceramic superstructures: chance or risk?

    PubMed

    Rinke, Sven

    2015-03-01

    The use of zirconia abutments for single-tooth restorations is well documented and supported by clinical studies with observational periods of up to 5 years. However, data for fixed partial dentures (FPDs) on all-ceramic abutments are lacking. Therefore, this indication cannot yet be generally recommended. Based on the available clinical studies, it can be assumed that the treatment results for anterior restorations can be improved by using all-ceramic abutments, especially in situations with a reduced thickness of the peri-implant soft tissues (< 2 mm). Zirconia abutments for single-tooth restorations can be restored with glass-ceramic crowns on a lithium-disilicate base or crowns with oxide-ceramic structures (alumina or zirconia). If the restorations are cemented adhesively, then all of the cement residues must be carefully removed. Superstructures based on zirconia ceramics can be removed to a certain degree if they are cemented temporarily or screwfixed with directly veneered abutments. However, prior to providing a general recommendation for temporary cementation or screw-fixation of all-ceramic superstructures, additional clinical data are needed.

  11. Comparison of Dental School and Practicing Dentists' Restorative Treatment Recommendations.

    ERIC Educational Resources Information Center

    Bader, James D.; And Others

    1995-01-01

    Comparison and analysis of the restorative treatment recommendations made by dentists and dental school students for 63 patients found about 85% agreement on treatment plans. It is observed that the results provide some basis on which to assess how well dental school treatments reflect mainstream practice. (MSE)

  12. Loss of Alloy in Cast Restorations Fabricated by Dental Students.

    ERIC Educational Resources Information Center

    Soh, George

    1991-01-01

    A study investigated the quantity of alloy lost in the fabrication of three types of cast restoration by dental students, and identified the proportion of loss at each of the four principal stages of the fabrication process. Suggestions for reducing metal loss and related costs in dental schools are offered. (MSE)

  13. The demand for preventive and restorative dental services.

    PubMed

    Meyerhoefer, Chad D; Zuvekas, Samuel H; Manski, Richard

    2014-01-01

    Chronic tooth decay is the most common chronic condition in the United States among children ages 5-17 and also affects a large percentage of adults. Oral health conditions are preventable, but less than half of the US population uses dental services annually. We seek to examine the extent to which limited dental coverage and high out-of-pocket costs reduce dental service use by the nonelderly privately insured and uninsured. Using data from the 2001-2006 Medical Expenditure Panel Survey and an American Dental Association survey of dental procedure prices, we jointly estimate the probability of using preventive and both basic and major restorative services through a correlated random effects specification that controls for endogeneity. We found that dental coverage increased the probability of preventive care use by 19% and the use of restorative services 11% to 16%. Both conditional and unconditional on dental coverage, the use of dental services was not sensitive to out-of-pocket costs. We conclude that dental coverage is an important determinant of preventive dental service use, but other nonprice factors related to consumer preferences, especially education, are equal if not stronger determinants.

  14. Nanotechnology-based restorative materials for dental caries management

    PubMed Central

    Melo, Mary A.S.; Guedes, Sarah F.F.; Xu, Hockin H.K.; Rodrigues, Lidiany K.A.

    2013-01-01

    Nanotechnology has been applied to dental materials as an innovative concept for the development of materials with better properties and anticaries potential. In this review we discuss the current progress and future applications of functional nanoparticles incorporated in dental restorative materials as useful strategies to dental caries management. We also overview proposed antimicrobial and remineralizing mechanisms. Nanomaterials have great potential to decrease biofilm accumulation, inhibit the demineralization process, to be used for remineralizing tooth structure, and to combat caries-related bacteria. These results are encouraging and open the doors to future clinical studies that will allow the therapeutic value of nanotechnology-based restorative materials to be established. PMID:23810638

  15. Finite element calculation of residual stress in dental restorative material

    NASA Astrophysics Data System (ADS)

    Grassia, Luigi; D'Amore, Alberto

    2012-07-01

    A finite element methodology for residual stresses calculation in dental restorative materials is proposed. The material under concern is a multifunctional methacrylate-based composite for dental restorations, activated by visible light. Reaction kinetics, curing shrinkage, and viscoelastic relaxation functions were required as input data on a structural finite element solver. Post cure effects were considered in order to quantify the residual stresses coming out from natural contraction with respect to those debited to the chemical shrinkage. The analysis showed for a given test case that residual stresses frozen in the dental restoration at uniform temperature of 37°C are of the same order of magnitude of the strength of the dental composite material per se.

  16. Zirconium dioxide based dental restorations. Studies on clinical performance and fracture behaviour.

    PubMed

    Larsson, Christel

    2011-01-01

    Loss of teeth can affect a person's appearance and functions such as eating and speaking. There is thus a need for prosthetic rehabilitation to improve quality of life. For many patients, a fixed dental restoration is preferred, and a common restoration is a porcelain-fused-to-metal bridge retained by teeth or implants. Metal-based restorations can potentially cause adverse reactions though, and this is cause for the search for alternative materials. All-ceramic materials are characterized by strong atomic bonds that make them reluctant to react with the environment, and thus unlikely to cause adverse reactions. All-ceramic materials have other attractive material properties and excellent aesthetic properties and have been successfully used in dentistry, mostly for smaller anterior restorations. Ceramics, however, do not withstand tensile forces as well as metals, and are susceptible to brittle fractures with the connector area being especially prone to fracture. More recently, a new type of ceramic material, based on zirconium dioxide, has been developed. Yttria-stabilized tetragonal zirconia polycrystal, Y-TZP, has a unique ability to resist crack propagation by being able to transform from one crystalline phase to another, and the resultant volume increase stops the crack and prevents it from propagating. This material has the potential to be used for larger restorations and in the molar area. Not enough information, however, is available on clinical follow-up of zirconia-based restorations, especially long-term, and information about all-ceramic restorations supported by implants is lacking. The aim of this thesis was to evaluate designs of zirconia-based restorations in relation to achieving increased fracture resistance and evaluate the clinical performance of implant-supported zirconia-based restorations. In paper I implant-supported all-ceramic fixed partial dentures of two different ceramic materials were compared; a zirconia-toughened alumina material

  17. Effect of Industry Sponsorship on Dental Restorative Trials.

    PubMed

    Schwendicke, F; Tu, Y-K; Blunck, U; Paris, S; Göstemeyer, G

    2016-01-01

    Industry sponsorship was found to potentially introduce bias into clinical trials. We assessed the effects of industry sponsorship on the design, comparator choice, and findings of randomized controlled trials on dental restorative materials. A systematic review was performed via MEDLINE, CENTRAL, and EMBASE. Randomized trials on dental restorative and adhesive materials published 2005 to 2015 were included. The design of sponsored and nonsponsored trials was compared statistically (risk of bias, treatment indication, setting, transferability, sample size). Comparator choice and network geometry of sponsored and nonsponsored trials were assessed via network analysis. Material performance rankings in different trial types were estimated via Bayesian network meta-analysis. Overall, 114 studies were included (15,321 restorations in 5,232 patients). We found 21 and 41 (18% and 36%) trials being clearly or possibly industry sponsored, respectively. Trial design of sponsored and nonsponsored trials did not significantly differ for most assessed items. Sponsored trials evaluated restorations of load-bearing cavities significantly more often than nonsponsored trials, had longer follow-up periods, and showed significantly increased risk of detection bias. Regardless of sponsorship status, comparisons were mainly performed within material classes. The proportion of trials comparing against gold standard restorative or adhesive materials did not differ between trial types. If ranked for performance according to the need to re-treat (best: least re-treatments), most material combinations were ranked similarly in sponsored and nonsponsored trials. The effect of industry sponsorship on dental restorative trials seems limited.

  18. Various Effects of Sandblasting of Dental Restorative Materials

    PubMed Central

    Nishigawa, Goro; Maruo, Yukinori; Irie, Masao; Maeda, Naoto; Yoshihara, Kumiko; Nagaoka, Noriyuki; Matsumoto, Takuya; Minagi, Shogo

    2016-01-01

    Background Sandblasting particles which remain on the surfaces of dental restorations are removed prior to cementation. It is probable that adhesive strength between luting material and sandblasting particle remnants might exceed that with restorative material. If that being the case, blasting particles adhere to sandblasted material surface could be instrumental to increasing adhesive strength like underlying bonding mechanism between luting material and silanized particles of tribochemical silica coating-treated surface. We hypothesize that ultrasonic cleaning of bonding surfaces, which were pretreated with sandblasting, may affect adhesive strength of a resin luting material to dental restorative materials. Methods We therefore observed adhesive strength of resin luting material to aluminum oxide was greater than those to zirconia ceramic and cobalt-chromium alloy beforehand. To measure the shear bond strengths of resin luting material to zirconia ceramic and cobalt-chromium alloy, forty specimens of each restorative material were prepared. Bonding surfaces were polished with silicon abrasive paper and then treated with sandblasting. For each restorative material, 40 sandblasted specimens were equally divided into two groups: ultrasonic cleaning (USC) group and non-ultrasonic cleaning (NUSC) group. After resin luting material was polymerized on bonding surface, shear test was performed to evaluate effect of ultrasonic cleaning of bonding surfaces pretreated with sandblasting on bond strength. Results For both zirconia ceramic and cobalt-chromium alloy, NUSC group showed significantly higher shear bond strength than USC group. Conclusions Ultrasonic cleaning of dental restorations after sandblasting should be avoided to retain improved bonding between these materials. PMID:26764913

  19. The Decim system for the production of dental restorations.

    PubMed

    Sjölin, R; Sundh, A; Bergman, M

    1999-07-01

    The general background to the development of CAD/CAM is presented in short. Specific problems when using this technique for the manufacturing of dental restorations are emphasized, and then the reverse engineering and CAD/CAM process that have been implemented in the Decim (Dentronic AB, Skellefteå, Sweden) system are presented. The system is organized in the following way: 1. The measurement process is encapsulated in a product called Decim Reader. 2. The design functionality is provided by software running on a conventional personal computer. This unit is called Decim Designer. 3. The CAM calculation is done by a dedicated personal computer, the Decim Calculator, that does not require any user interaction. 4. The actual manufacturing of the restorations is performed in the Decim Producer that works with a grinding technique. These components communicate via a local computer network or, when a distributed solution is desired, via internet. The Decim System is presently used for the production of dental ceramic restorations, and it is the only system which can be used for manufacturing inlays of yttria-stabilized zirconia. This ceramic material is CE-approved under the brand name Denzir (Dentronic AB, Skellefteå, Sweden). Due to its favorable mechanical properties, it may be an alternative to dental amalgam, and is therefore of topical interest in dentistry. The use of computer-based techniques for manufacturing dental restorations is briefly outlined and commented on.

  20. Regression of oral lichenoid lesions after replacement of dental restorations.

    PubMed

    Mårell, L; Tillberg, A; Widman, L; Bergdahl, J; Berglund, A

    2014-05-01

    The aim of the study was to determine the prognosis and to evaluate the regression of lichenoid contact reactions (LCR) and oral lichen planus (OLP) after replacement of dental restorative materials suspected as causing the lesions. Forty-four referred patients with oral lesions participated in a follow-up study that was initiated an average of 6 years after the first examination at the Department of Odontology, i.e. the baseline examination. The patients underwent odontological clinical examination and answered a questionnaire with questions regarding dental health, medical and psychological health, and treatments undertaken from baseline to follow-up. After exchange of dental materials, regression of oral lesions was significantly higher among patients with LCR than with OLP. As no cases with OLP regressed after an exchange of materials, a proper diagnosis has to be made to avoid unnecessary exchanges of intact restorations on patients with OLP.

  1. Confined compression of dental composites for Class I restorations

    PubMed Central

    Patki, Amol S.; Vural, Murat; Gosz, Mike

    2011-01-01

    This study focuses on the mechanical response of a particle-reinforced restorative dental composite (Renew™) under proportional transverse confinement to understand the effects of stress multiaxiality on its mechanical and failure behaviors. We describe the confining ring technique as an experimental tool to introduce multiaxial compressive stress states in dental composites that realistically mimic three-dimensional stress states commonly experienced by dental restorations in the oral cavity. Effect of initial radial misfit between confining ring and specimen is analyzed through computational finite element simulations, and an analytical treatment of problem is also provided to compute the confining stress during elasto-plastic expansion of confining ring. Experimental results suggest that inelastic response of Renew composite is significantly influenced by hydrostatic stress component, and pressure-dependent yield functions are required to analyze plastic deformations and internal damage accumulation process. PMID:21857744

  2. Recent advances and developments in composite dental restorative materials.

    PubMed

    Cramer, N B; Stansbury, J W; Bowman, C N

    2011-04-01

    Composite dental restorations represent a unique class of biomaterials with severe restrictions on biocompatibility, curing behavior, esthetics, and ultimate material properties. These materials are presently limited by shrinkage and polymerization-induced shrinkage stress, limited toughness, the presence of unreacted monomer that remains following the polymerization, and several other factors. Fortunately, these materials have been the focus of a great deal of research in recent years with the goal of improving restoration performance by changing the initiation system, monomers, and fillers and their coupling agents, and by developing novel polymerization strategies. Here, we review the general characteristics of the polymerization reaction and recent approaches that have been taken to improve composite restorative performance.

  3. Early failure of Class II resin composite versus Class II amalgam restorations placed by dental students.

    PubMed

    Overton, J D; Sullivan, Diane J

    2012-03-01

    Using the information from remake request slips in a dental school's predoctoral clinic, we examined the short-term survival of Class II resin composite restorations versus Class II dental amalgam restorations. In the student clinic, resin composite is used in approximately 58 percent of Class II restorations placed, and dental amalgam is used in the remaining 42 percent. In the period examined, Class II resin composite restorations were ten times more likely to be replaced at no cost to the patient than Class II dental amalgam restorations. A total of eighty-four resin composite restorations and six amalgam restorations were replaced due to an identified failure.

  4. What constitutes an ideal dental restorative material?

    PubMed

    Rekow, E D; Bayne, S C; Carvalho, R M; Steele, J G

    2013-11-01

    Intense environmental concerns recently have prompted dentistry to evaluate the performance and environmental impact of existing restoration materials. Doing so entices us to explore the 'what if?' innovation in materials science to create more ideal restorative materials. Articulating a specification for our design and evaluation methods is proving to be more complicated than originally anticipated. Challenges exist not only in specifying how the material should be manipulated and perform clinically but also in understanding and incorporating implications of the skill of the operator placing the restoration, economic considerations, expectations patients have for their investment, cost-effectiveness, influences of the health care system on how and for whom restorations are to be placed, and global challenges that limit the types of materials available in different areas of the world. The quandary is to find ways to actively engage multiple stakeholders to agree on priorities and future actions to focus future directions on the creation of more ideal restorative materials that can be available throughout the world.

  5. Clinical Evaluation of Dental Restorative Materials

    DTIC Science & Technology

    1988-08-01

    of Nonprecious Alloys for Use with Porcelain Veneers . Part One, Physical Properties, J. Prosth Dent, 30: 424-431, 1973. Page 13...manufacturer (Jelenko and Company, Armonk, New York) recommends the use of their "thermotrol" casting set up. Attempt to cast this alloy with this piece of ...Nielsen, J.P. and Tuccillo, J’.J.: Calculations of Interfacial Stress in Dental Porcelain Bonded to Gold Alloy Substrate

  6. A panorama of dental CAD/CAM restorative systems.

    PubMed

    Liu, Perng-Ru

    2005-07-01

    In the last 2 decades, exciting new developments in dental materials and computer technology have led to the success of contemporary dental computer-aided design/computer-aided manufacturing (CAD/CAM) technology. Several highly sophisticated chairside and laboratory CAD/CAM systems have been introduced or are under development. This article provides an overview of the development of various CAD/CAM systems. Operational components, methodologies, and restorative materials used with common CAD/CAM systems are discussed. Research data and clinical studies are presented to substantiate the clinical performance of these systems.

  7. Panorama of dental CAD/CAM restorative systems.

    PubMed

    Liu, Perng-Ru; Essig, Milton E

    2008-10-01

    In the past two decades, exciting new developments in dental materials and computer technology have led to the success of contemporary dental computer-aided design/computer-aided manufacture (CAD/CAM) technology. Several highly sophisticated in-office and laboratory CAD/CAM systems have been introduced or are under development. This article provides an overview of the development of various CAD/CAM systems. Operational components, methodologies, and restorative materials used with common CAD/CAM systems are discussed. Research data and clinical studies are presented to substantiate the clinical performance of these systems.

  8. Backscattering from dental restorations and splint materials during therapeutic radiation

    SciTech Connect

    Farman, A.G.; Sharma, S.; George, D.I.; Wilson, D.; Dodd, D.; Figa, R.; Haskell, B.

    1985-08-01

    Models were constructed to simulate as closely as possible the human oral cavity. Radiation absorbed doses were determined for controls and various test situations involving the presence of dental restorative and splint materials during cobalt-60 irradiation of the models. Adjacent gold full crowns and adjacent solid dental silver amalgam cores both increased the dose to the interproximal gingivae by 20%. Use of orthodontic full bands for splinting the jaws increased the dose to the buccal tissues by an average of 10%. Augmentation of dose through backscatter radiation was determined to be only slight for intracoronal amalgam fillings and stainless steel or plastic bracket splints.

  9. Detecting margin leakage of dental composite restorations

    SciTech Connect

    Wu, W.; Cobb, E.; Dermann, K.; Rupp, N.W.

    1983-01-01

    The degree of microleakage between a restoration and the cavity wall is difficult to quantify objectively. A silver-staining method is used and compared to the radioisotope method with results that indicate a superior definition and more accurate evaluation of microleakage. In addition to the accuracy, two advantages are presented: (1) scoring of the leakage can be refined and divided into more precise numbers, and (2) teeth can be observed directly in a microscope without resorting to the indirect interpretation of film or photograph.

  10. Recent Advances and Developments in Composite Dental Restorative Materials

    PubMed Central

    Cramer, N.B.; Stansbury, J.W.; Bowman, C.N.

    2011-01-01

    Composite dental restorations represent a unique class of biomaterials with severe restrictions on biocompatibility, curing behavior, esthetics, and ultimate material properties. These materials are presently limited by shrinkage and polymerization-induced shrinkage stress, limited toughness, the presence of unreacted monomer that remains following the polymerization, and several other factors. Fortunately, these materials have been the focus of a great deal of research in recent years with the goal of improving restoration performance by changing the initiation system, monomers, and fillers and their coupling agents, and by developing novel polymerization strategies. Here, we review the general characteristics of the polymerization reaction and recent approaches that have been taken to improve composite restorative performance. PMID:20924063

  11. A Review of Developments in Computer-Based Systems to Image Teeth and Produce Dental Restorations

    PubMed Central

    Rekow, E. Dianne; Erdman, Arthur G.; Speidel, T. Michael

    1987-01-01

    Computer-aided design and manufacturing (CAD/CAM) make it possible to automate the creation of dental restorations. Currently practiced techniques are described. Three automated systems currently under development are described and compared. Advances in computer-aided design and computer-aided manufacturing (CAD/CAM) provide a new option for dentistry, creating an alternative technique for producing dental restorations. It is possible to create dental restorations that are automatically produced and meet or exceed current requirements for fit and occlusion.

  12. Comparative study of mechanical properties of dental restorative materials and dental hard tissues in compressive loads

    PubMed Central

    Lee, Jong Yeop

    2014-01-01

    There are two objectives. One is to show the differences in the mechanical properties of various dental restorative materials compared to those of enamel and dentin. The other is to ascertain which dental restorative materials are more suitable for clinical treatments. Amalgam, dental ceramic, gold alloy, dental resin, zirconia, and titanium alloy were processed as dental restorative material specimens. The specimens (width, height, and length of 1.2, 1.2, and 3.0 mm, respectively) were compressed at a constant loading speed of 0.1 mm/min. The maximum stress (115.0 ± 40.6, 55.0 ± 24.8, 291.2 ± 45.3, 274.6 ± 52.2, 2206.0 ± 522.9, and 953.4 ± 132.1 MPa), maximum strain (7.8% ± 0.5%, 4.0% ± 0.1%, 12.7% ± 0.8%, 32.8% ± 0.5%, 63.5% ± 14.0%, and 45.3% ± 7.4%), and elastic modulus (1437.5 ± 507.2, 1548.4 ± 583.5, 2323.4 ± 322.4, 833.1 ± 92.4, 3895.2 ± 202.9, and 2222.7 ± 277.6 MPa) were evident for amalgam, dental ceramic, gold alloy, dental resin, zirconia, and titanium alloy, respectively. The reference hardness value of amalgam, dental ceramic, gold alloy, dental resin, zirconia, and titanium alloy was 90, 420, 130–135, 86.6–124.2, 1250, and 349, respectively. Since enamel grinds food, its abrasion resistance is important. Therefore, hardness value should be prioritized for enamel. Since dentin absorbs bite forces, mechanical properties should be prioritized for dentin. The results suggest that gold alloy simultaneously has a hardness value lower than enamel (74.8 ± 18.1), which is important in the wear of the opposing natural teeth, and higher maximum stress, maximum strain, and elastic modulus than dentin (193.7 ± 30.6 MPa, 11.9% ± 0.1%, 1653.7 ± 277.9 MPa, respectively), which are important considering the rigidity to absorb bite forces. PMID:25352921

  13. Rubber dam may increase the survival time of dental restorations.

    PubMed

    Keys, William; Carson, Susan J

    2017-03-01

    Data sourcesCochrane Oral Health's Trials Register, Cochrane Central Register of Controlled Trials (CENTRAL), Medline, Embase, LILACS, SciELO, Chinese BioMedical Literature Database, VIP, China National Knowledge Infrastructure, ClinicalTrials.gov, World Health Organization International Clinical Trials Registry Platform, OpenGrey and Sciencepaper Online databases. Handsearches in a number of journals.Study selectionRandomised controlled trials, including split-mouth studies assessing the effects of rubber dam isolation for restorative treatments in dental patients.Data extraction and synthesisTwo review authors independently screened the results of the electronic searches, extracted data and assessed the risk of bias of the included studies.ResultsFour studies involving a total of 1,270 patients were included. The studies were at high risk of bias. One trial was excluded from the analysis due to inconsistencies in the presented data. Restorations had a significantly higher survival rate in the rubber dam isolation group compared to the cotton roll isolation group at six months in participants receiving composite restorative treatment of non-carious cervical lesions (risk ratio (RR) 1.19, 95% confidence interval (CI) 1.04 to 1.37, very low-quality evidence). The rubber dam group had a lower risk of failure at two years in children undergoing proximal atraumatic restorative treatment in primary molars (hazard ratio (HR) 0.80, 95% CI 0.66 to 0.97, very low-quality evidence). One trial reported limited data showing that rubber dam usage during fissure sealing might shorten the treatment time. None of the included studies mentioned adverse effects or reported the direct cost of the treatment, or the level of patient acceptance/satisfaction. There was also no evidence evaluating the effects of rubber dam usage on the quality of the restorations.ConclusionsWe found some very low-quality evidence, from single studies, suggesting that rubber dam usage in dental direct

  14. Scattering and Absorption Properties of Biomaterials for Dental Restorative Applications

    NASA Astrophysics Data System (ADS)

    Fernandez-Oliveras, A.; Rubiño, M.; Pérez, M. M.

    2013-08-01

    The physical understanding of the optical properties of dental biomaterials is mandatory for their final success in restorative applications.Light propagation in biological media is characterized by the absorption coefficient, the scattering coefficient, the scattering phase function,the refractive index, and the surface conditions (roughness). We have employed the inverse adding-doubling (IAD) method to combine transmittance and reflectance measurements performed using an integrating-sphere setup with the results of the previous scattering-anisotropygoniometric measurements. This has led to the determination of the absorption and the scattering coefficients. The aim was to optically characterize two different dental-resin composites (nanocomposite and hybrid) and one type of zirconia ceramic, and comparatively study them. The experimental procedure was conducted under repeatability conditions of measurement in order to determine the uncertainty associated to the optical properties of the biomaterials. Spectral variations of the refraction index and the scattering anisotropy factor were also considered. The whole experimental procedure fulfilled all the necessary requirements to provide optical-property values with lower associated uncertainties. The effective transport coefficient presented a similar spectral behavior for the two composites but completely different for the zirconia ceramic. The results demonstrated that the scattering anisotropy exerted a clearly distinct impact on the optical properties of the zirconia ceramic compared with those of the dental-resin composites.

  15. Outcomes of implants and restorations placed in general dental practices

    PubMed Central

    Da Silva, John D.; Kazimiroff, Julie; Papas, Athena; Curro, Frederick A.; Thompson, Van P.; Vena, Donald A.; Wu, Hongyu; Collie, Damon; Craig, Ronald G.

    2017-01-01

    implants, 20 (2.2 percent) had restorations replaced or judged as needing to be replaced. The majority of P-Is and patients were satisfied with the esthetic outcomes for both the implant and restoration. Conclusions These results suggest that implant survival and success rates in general dental practices may be lower than those reported in studies conducted in academic or specialty settings. Practical Implications The results of this study, generated in the private general practice setting, add to the evidence base to facilitate implant treatment planning. PMID:24982276

  16. A silver staining technique for investigating wear of restorative dental composites

    SciTech Connect

    Wu, W.; Cobb, E.N.

    1981-05-01

    A silver staining technique was developed to demonstrate microdefects in dental restorative composites. Fine silver particles were preferentially introduced into the damaged region to provide optical contrast between the damaged and the undamaged regions. The amount of silver deposition determined with an electron probe microanalyzer, provided an indication of the extent of damage within the dental composites. Examples to demonstrate this technique were given with one clinically worn dental composite restoration and one in vitro worn composite sample.

  17. Fracture strength of all-ceramic restorations after fatigue loading

    NASA Astrophysics Data System (ADS)

    Baladhandayutham, Balasudha

    Fracture strength of monolithic and bilayered LAVA and e. max lower molar crowns after load cycling was measured and compared. The study included three groups (n = 8) from LAVA zirconia and three groups from e. max lithium disilicate to compare influences of different layers, thicknesses and manufacturing techniques. Prefabricated anatomically designed crowns were cemented to dies made from Z 100 composite resin using Rely X Luting Plus resin modified glass ionomer cement. Cemented crowns were stored at 37° C for 24 hours then cyclic loaded to test fatigue properties. The crowns were loaded to 200,000 cycles at 25N at a rate of 40 cycles / minute to simulate oral function. Subsequently, fracture properties for each group were measured using an Instron Universal Testing machine. Microscopic evaluation of the surface of fatigued samples did not reveal micro-cracks at the end of 50,000 cycles but minor wear facets were observed at the site of contact from the steatite ball antagonist. Crowns from LAVA bilayered groups showed step by step fractures while crowns from all other groups fractured as a single event as observed by the high speed camera. Zirconia bilayered crowns showed the highest loads to fracture while lithium disilicate monolithic crowns showed the lowest, within the limitations of the study. The study also showed that monolithic zirconia crowns of 0.6mm thickness resulted in relatively high magnitude for forces at fracture.

  18. Marginal Integrity of Glass Ionomer and All Ceramic Restorations

    DTIC Science & Technology

    2015-06-01

    irregular microstructure of the glass matrix infused with fillers, they do not possess fracture resistance comparable to natural teeth. This limited ACRs...content and lower glass content, these ceramics have greater fracture resistance. These improved ceramics can be used in areas with significant lateral...Reitz, 1999). The polycrystalline structure has a much 3 higher resistance to fracture than the less dense and irregular composition of glass

  19. Mechanical performance of novel bioactive glass containing dental restorative composites

    PubMed Central

    Khvostenko, D.; Mitchell, J. C.; Hilton, T. J.; Ferracane, J. L.; Kruzic, J. J.

    2013-01-01

    Objectives Bioactive glass (BAG) is known to possess antimicrobial properties and release ions needed for remineralization of tooth tissue, and therefore may be a strategic additive for dental restorative materials. The objective of this study was to develop BAG containing dental restorative composites with adequate mechanical properties comparable to successful commercially available composites, and to confirm the stability of these materials when exposed to a biologically challenging environment. Methods Composites with 72 wt.% total filler content were prepared while substituting 0–15% of the filler with ground BAG. Flexural strength, fracture toughness, and fatigue crack growth tests were performed after several different soaking treatments: 24 hours in DI water (all experiments), two months in brain-heart infusion (BHI) media+S. mutans bacteria (all experiments) and two months in BHI media (only for flexural strength). Mechanical properties of new BAG composites were compared along with the commercial composite Heliomolar by two-way ANOVA and Tukey’s multiple comparison test (p≤0.05). Results Flexural strength, fracture toughness, and fatigue crack growth resistance for the BAG containing composites were unaffected by increasing BAG content up to 15% and were superior to Heliomolar after all post cure treatments. The flexural strength of the BAG composites was unaffected by two months exposure to aqueous media and a bacterial challenge, while some decreases in fracture toughness and fatigue resistance were observed. The favorable mechanical properties compared to Heliomolar were attributed to higher filler content and a microstructure morphology that better promoted the toughening mechanisms of crack deflection and bridging. Significance Overall, the BAG containing composites developed in this study demonstrated adequate and stable mechanical properties relative to successful commercial composites. PMID:24050766

  20. Phase identification in dental porcelains for ceramo-metallic restorations.

    PubMed

    Barreiro, M M; Riesgo, O; Vicente, E E

    1989-01-01

    Most commercial dental porcelains designed for ceramo-metallic restorations are partially crystallized feldspathic glasses (glass-ceramics) that consist of low (tetragonal) leucite (K2O.Al2O3.4SiO2) crystals embedded in a glassy matrix. In this work, we have identified the crystalline phases in eight commercial dental porcelains (four enamels and four dentin bodies) in both powder (unfired) and sintered forms, by x-ray diffraction, emission spectroscopy analysis, reflection optical microscopy, and scanning electron microscopy. Besides low leucite and glass, we have found a second crystalline phase in the sintered and slow-cooled porcelains that we propose to be potash feldspar (K2O.Al2O3.6SiO2). It was impossible to ascertain whether these synthetic crystals may be sanidine, orthoclase, or microcline. The precipitation of feldspar during cooling is explained in terms of the crystallization behavior of typical body compositions in the ternary-phase diagram K2O-Al2O3-SiO2. Ceramography confirms the martensitic (displacive) nature of the transformation from high (cubic) to low (tetragonal) leucite upon cooling.

  1. Embryotoxicity assays for leached components from dental restorative materials

    PubMed Central

    2011-01-01

    Background Currently, there are no suitable assays available to evaluate the embryotoxicity of leached components from restorative dental materials. Methods The effect of the medium conditioned by composites and amalgam on mouse blastocysts in vitro was tested. The materials were also subcutaneously implanted, and the effect of the medium supplemented with serum from the host blood was evaluated in the embryotoxicity assay. The embryo implantation rate in the material-transplanted mothers was also evaluated. Results The results show that while the culture in media conditioned by amalgams did not affect blastocyst development, the medium conditioned by composites caused blastocyst degeneration and apoptosis. The development of blastocysts in a medium containing serum obtained from animals after transplantation was, however, without effect. Finally, inconsistent reduction in the implantation rate in transplanted mothers was observed. Conclusions In this study, we provide examples of in vitro and in vivo tests that may be used to evaluate embryotoxicity for dental materials. Our results show that leached components from our composite-material induced embryotoxicity in vitro, however, no toxicity was observed when subcutaneously implanted in vivo. This highlights the necessity of integrated in vitro and in vivo tests for valuable predictive estimation of embryotoxicity for complex materials. PMID:21978455

  2. [Atraumatic restorative treatment in relation to pain, discomfort and dental treatment anxiety].

    PubMed

    Frencken, J E F M; Flohil, K A; de Baat, C

    2014-01-01

    Dental treatment anxiety usually develops during childhood due to a bad experience and the dental drill as well as the injection needle are the most common causes. The Atraumatic Restorative Treatment provides the opportunity to provoke little or no dental treatment anxiety because only hand instruments are used and local anaesthesia is seldom required. Several scientific studies have indicated that the Atraumatic Restorative Treatment causes less pain, discomfort and anxiety by comparison with conventional treatments. Therefore, the Atraumatic Restorative Treatment is considered to be promising for the treatment of carious lesions in anxious children and adults, and potentially also for patients suffering from dental treatment phobia. Furthermore, the Atraumatic Restorative Treatment may be indicated as the primary treatment method in children to prevent dental treatment anxiety and treatment under general anaesthesia. These conclusions must still be confirmed with responsible scientific research.

  3. Understanding dental CAD/CAM for restorations - dental milling machines from a mechanical engineering viewpoint. Part A: chairside milling machines.

    PubMed

    Lebon, Nicolas; Tapie, Laurent; Duret, Francois; Attal, Jean-Pierre

    2016-01-01

    The dental milling machine is an important device in the dental CAD/CAM chain. Nowadays, dental numerical controlled (NC) milling machines are available for dental surgeries (chairside solution). This article provides a mechanical engineering approach to NC milling machines to help dentists understand the involvement of technology in digital dentistry practice. First, some technical concepts and definitions associated with NC milling machines are described from a mechanical engineering viewpoint. The technical and economic criteria of four chairside dental NC milling machines that are available on the market are then described. The technical criteria are focused on the capacities of the embedded technologies of these milling machines to mill both prosthetic materials and types of shape restorations. The economic criteria are focused on investment costs and interoperability with third-party software. The clinical relevance of the technology is assessed in terms of the accuracy and integrity of the restoration.

  4. Cluster Effects in a National Dental PBRN Restorative Study

    PubMed Central

    Litaker, M.S.; Gordan, V.V.; Rindal, D.B.; Fellows, J.L.; Gilbert, G.H.

    2013-01-01

    Items in clusters, such as patients of the same clinician or teeth within the same patient, tend to be more similar than items from different groups. This within-group similarity, represented by the intraclass correlation coefficient (ICC), reduces precision, yielding less statistical power and wider confidence intervals, compared with non-clustered samples of the same size. This must be considered in the design of studies including clusters. We present ICC estimates from a study of 7,826 restorations placed in previously unrestored tooth surfaces of 4,672 patients by 222 clinicians in the National Dental Practice-Based Research Network, as a resource for sample size planning in restorative studies. Our findings suggest that magnitudes of ICCs in practice-based research can be substantial. These can have large effects on precision and the power to detect treatment effects. Generally, we found relatively large ICCs for characteristics that are influenced by clinician choice (e.g., 0.36 for rubber dam use). ICCs for outcomes within individual patients, such as tooth surfaces affected by a caries lesion, tended to be smaller (from 0.03 to 0.15), but were still sufficiently large to substantially affect statistical power. Clustering should be taken into account in the design of oral health studies and derivation of statistical power estimates for these studies (ClinicalTrials.gov, NCT00847470). PMID:23857643

  5. Evaluation of efficacy of restorative dental treatment provided under general anesthesia at hospitalized pediatric dental patients of Isfahan

    PubMed Central

    Eshghi, Alireza; Samani, Mahdi Jafarzadeh; Najafi, Naghme Feyzi; Hajiahmadi, Maryam

    2012-01-01

    Background: General anesthesia (GA) allows dental treatment to be rendered under optimal conditions, theoretically ensuring ideal outcomes. The aim of this study was to determine the efficacy of restorative dental procedures performed under GA. Materials and Methods: In this cross-sectional retrospective study, 305 pediatric patients who had been treated under GA 6 to 24 months before our survey at Isfahan's hospitalized dentistry center were examined. The examination was performed on dental chair with oral mirror and dental probe. The results were recorded in a special form for each patient for statistical analysis and evaluation of restorations to be successful or failed. Statistical analysis was performed by chi-square and fisher exact tests for comparison between success rates of restorations and Kendall's tau-b test for evaluating the effect of time on success rates of them (P < 0.05). Results: Stainless steel crown restorations had significantly better results vs class I and class II amalgam and class I and class II tooth color restorations. All types of posterior tooth color restorations had statistically same results with amalgam restorations. Anterior composite resin build-up represented significantly low success rates. The failure rates of stainless steel crown and anterior composite resin build-up restorations did not correlate with the time of follow-up (P = 0.344 and P = 0.091, respectively). Conclusion: Stainless steel crown restorations had significantly better results vs other posterior restorations. The failure rates of stainless steel crown and anterior composite resin build-up restorations did not correlate with the time of follow-up in comparison of other restorations. PMID:23162592

  6. Antibacterial activity of restorative dental biomaterials in vitro.

    PubMed

    Boeckh, Clemens; Schumacher, Eliane; Podbielski, Andreas; Haller, Bernd

    2002-01-01

    This study investigated the antibacterial effects against Streptococcus mutans of a fine-hybrid resin composite (FH-RC; Tetric ceram), an ion-releasing resin composite (Ariston pHc), a self-curing glass ionomer cement (SC-GIC; Ketac-Molar), a resin-modified GIC (RM-GIC; Photac-Fil), and a zinc oxide eugenol cement (ZOE; IRM). In a novel assay, bacterial suspensions were placed into narrow 20-microl conical cavities within the materials. After 0, 4, 8, 24, 48 h and 1 week of incubation, the suspensions were removed from the restoratives and the numbers of viable bacteria were determined. After incubation periods of 8 h or more, all restorative materials except the FH-RC showed significant growth inhibition when compared with controls. The strongest antibacterial activity was observed with ZOE. The inhibitory effect of Ariston pHc was similar to that of the SC-GIC and the RM-GIC. In the second assay, growth inhibition was evaluated in liquid cultures by incubating eluates of the materials with suspensions of S. mutans. Bacterial growth was determined up to 6 h by measuring absorption at 600 nm. The most marked inhibitory effect was again observed with ZOE. The SC-GIC caused a significant inhibition at all time intervals but the FH-RC, the RM-GIC and Ariston pHc exhibited no significant antibacterial effects. It is recommended to employ more than one method for assessing the antibacterial potential of restorative materials. Long-term clinical trials are necessary to determine whether the antimicrobial effects of dental materials are able to reduce the risk of secondary caries formation.

  7. A useful and non-invasive microanalysis method for dental restoration materials

    NASA Astrophysics Data System (ADS)

    Hosoki, M.; Satsuma, T.; Nishigawa, K.; Takeuchi, H.; Asaoka, K.

    2012-12-01

    The elemental analysis of intraoral dental restorations provides considerable information for the treatment of dental metal allergy. Elemental analyses require specific instruments and complicated procedures, so this examination is not commonly carried out in private dental clinics. We describe a novel, simple and useful micro-analytical method for dental metal restorations. Micro metal dust was obtained by polishing the surface of restorative metal material with an unused silicone point (SUPER-SNAP). The metal dust on the silicone point was then rubbed onto adhesive tape, and this tape was covered with polyethylene film. The amount of metal dust material was <20 μg. An energy dispersive X-ray fluorescence spectrometer was used to carry out the elementary analysis of the metal dust on the polyethylene film. Three types of dental metal alloy materials of known components were examined. The results of elementary analyses were compared with the specifications provided by the manufacturer. The same procedure was carried out for three dental metal restorations of an adult female volunteer in vivo. The results of elemental analyses for five alloy materials exactly matched the product specification. Three metal samples obtained from intraoral restoration were also available for elemental analyses. The distinct advantage of this method is that it enables sample extraction without an invasive effect for the restoration. The metal sample is in a polyethylene film, so it is easy to mail it for inspection at specialist institutes yet it can be also be used in general dental clinics.

  8. Influence of gag reflex on dental attendance, dental anxiety, self-reported temporomandibular disorders and prosthetic restorations.

    PubMed

    Akarslan, Z Z; Yıldırım Biçer, A Z

    2013-12-01

    To assess the influence of gag reflex severity, assessed according to the short form of the patient part of Gagging Problem Assessment Questionnaire (GPA-pa SF), on the dental attendance, dental anxiety, self-reported temporomandibular disorder (TMD) symptoms and presence of prosthetic restorations among patients requiring prosthodontic treatment in Turkey. A total of 505 patients (305 women; mean age: 46·35 years, SD: 28·2 years) undergoing dental examination were administered a questionnaire containing questions regarding their age, gender, education level, dental attendance, TMD symptoms (limitation in jaw opening, muscle pain, pain/sounds in the temporomandibular jaw), the Turkish version of the Modified Dental Anxiety Scale (MDAS) and the GPA-pa SF. Subsequently, any prosthetic restoration was recorded by a dentist. Descriptive statistics, one-way analysis of variance (anova) and the chi-square test were used for statistical analysis. Differences were found between GPA-pa SF scores 0, 1 and 2 for education level (P = 0·001), MDAS scores (P = 0·003), self-reported TMD (P = 0·000) and prosthesis wear (P = 0·000), but not for attendance patterns (P = 0·826). Patients with gag reflex had lower education levels, higher levels of dental anxiety, more self-reported TMD symptoms and fewer fixed or removable prosthetic restorations than patients without gag reflex. Gag reflex has impacts on dental anxiety, self-reported TMD and prosthetic restorations, but not on dental attendance patterns, according to the results of the GPA-pa SF.

  9. Machinable glass-ceramics forming as a restorative dental material.

    PubMed

    Chaysuwan, Duangrudee; Sirinukunwattana, Krongkarn; Kanchanatawewat, Kanchana; Heness, Greg; Yamashita, Kimihiro

    2011-01-01

    MgO, SiO(2), Al(2)O(3), MgF(2), CaF(2), CaCO(3), SrCO(3), and P(2)O(5) were used to prepare glass-ceramics for restorative dental materials. Thermal properties, phases, microstructures and hardness were characterized by DTA, XRD, SEM and Vickers microhardness. Three-point bending strength and fracture toughness were applied by UTM according to ISO 6872: 1997(E). XRD showed that the glass crystallized at 892°C (second crystallization temperature+20°C) for 3 hrs consisted mainly of calcium-mica and fluorapatite crystalline phases. Average hardness (3.70 GPa) closely matched human enamel (3.20 GPa). The higher fracture toughness (2.04 MPa√m) combined with the hardness to give a lower brittleness index (1.81 µm(-1/2)) which indicates that they have exceptional machinability. Bending strength results (176.61 MPa) were analyzed by Weibull analysis to determine modulus value (m=17.80). Machinability of the calcium mica-fluorapatite glass-ceramic was demonstrated by fabricating with CAD/CAM.

  10. Biofilm formation on dental restorative and implant materials.

    PubMed

    Busscher, H J; Rinastiti, M; Siswomihardjo, W; van der Mei, H C

    2010-07-01

    Biomaterials for the restoration of oral function are prone to biofilm formation, affecting oral health. Oral bacteria adhere to hydrophobic and hydrophilic surfaces, but due to fluctuating shear, little biofilm accumulates on hydrophobic surfaces in vivo. More biofilm accumulates on rough than on smooth surfaces. Oral biofilms mostly consist of multiple bacterial strains, but Candida species are found on acrylic dentures. Biofilms on gold and amalgam in vivo are thick and fully covering, but barely viable. Biofilms on ceramics are thin and highly viable. Biofilms on composites and glass-ionomer cements cause surface deterioration, which enhances biofilm formation again. Residual monomer release from composites influences biofilm growth in vitro, but effects in vivo are less pronounced, probably due to the large volume of saliva into which compounds are released and its continuous refreshment. Similarly, conflicting results have been reported on effects of fluoride release from glass-ionomer cements. Finally, biomaterial-associated infection of implants and devices elsewhere in the body is compared with oral biofilm formation. Biomaterial modifications to discourage biofilm formation on implants and devices are critically discussed for possible applications in dentistry. It is concluded that, for dental applications, antimicrobial coatings killing bacteria upon contact are more promising than antimicrobial-releasing coatings.

  11. In situ reaction kinetic analysis of dental restorative materials

    NASA Astrophysics Data System (ADS)

    Younas, Basma; Samad Khan, Abdul; Muzaffar, Danish; Hussain, Ijaz; Chaudhry, Aqif Anwar; Rehman, Ihtesham Ur

    2013-12-01

    The objective of this study was to evaluate in situ structural and thermal changes of dental restorative materials at periodical time intervals. The commercial materials included zinc oxide eugenol (ZOE), zinc phosphate type I (ZnPO4), glass ionomer cement type II (GIC) and resin-based nano-omposite (Filtek Z350 XT). These materials were processed according to manufacturer's instructions. For the structural analysis Fourier transform infrared spectroscopy (FTIR) was used at high resolution. TGA was used to evaluate thermal weight-loss. The FTIR spectra were collected at periodic time intervals. FTIR spectra showed that with time passing all materials exhibited an increase in peak intensities and a new appearance of shoulders and shifting of peaks for example, ZnPO4 (P-O), ZOE (C═O, C═N, C-O-C), GIC (COO-, C-H, Si-OH), composites (C═O, C═C, C═N, C-N-H). The peaks were replaced by bands and these bands became broader with time interval. Composites showed a degree of conversion and new peaks corresponded to the cross-linking of polymer composites. TGA analysis showed that significant changes in weight loss of set materials were observed after 24 h, where ZOE showed continuous changes in thermal degradation. The spectral changes and thermal degradation with time interval elucidated in situ setting behaviour and understanding of their bonding compatibility with tooth structure and change in relation to time.

  12. Fracture Analysis of an All-Ceramic Bearing System

    DTIC Science & Technology

    1994-09-01

    APPLICATION Miniature all- ceramic (NBD-200 silicon nitride) gimbal and spin bearings were developed for a common IR seeker, Figure 1, to be employed in the...as both a free gyro and optics system for the seeker. The main driving force behind the development of the all- ceramic bearings was to increase bearing ...sufficient for this ceramic bearing application. 1) Develop a machining procedure specifically for the raceways. 2) Reduce the material removal rate

  13. Legislation and informed consent brochures for dental patients receiving amalgam restorations.

    PubMed

    Edlich, Richard F; Cochran, Amy A; Cross, Catherine L; Wack, Courtney A; Long, William B; Newkirk, Anthony T

    2008-01-01

    In 2008, Norway banned the use of mercury for amalgam restorations. Four states in the United States have developed Informed Consent Brochures for amalgam restorations that must be given to their dental patients. The authors describe a patient who had a large cavity in his left lower molar tooth no.18 that had to be removed by an oral surgeon. When the patient went to the oral surgeon, the surgeon told the patient that he would replace the carious tooth with a gold implant. He was not given an Informed Consent Brochure regarding dental restorative materials. The oral surgeon extracted the carious tooth, replacing the tooth with a supposed gold crown implant. On his yearly dental examination, his dentist took an x-ray of his dental implant and explained that the x-ray could not distinguish whether the implant contained either gold or mercury. Consequently, the dentist referred him to a dental clinic in which the dental implant could be removed without mercury contamination of the patient's neurologic system during the extraction of the implant from the root canal. During the removal of the dental restoration, the dentist found build up expanding into the root canal that had a black color. The crown and underlying tooth were sent to ALT BioScience for analysis. Elemental analysis of the crown and underlying tooth confirmed the presence of mercury in the restoration. The patient should have been given an Informed Consent Brochure by the dentist that described the dental restoration that was used in the dental implant.

  14. Reduction of load-bearing capacity of all-ceramic crowns due to cement aging.

    PubMed

    Lu, Chenglin; Wang, Raorao; Mao, Shuangshuang; Arola, Dwayne; Zhang, Dongsheng

    2013-01-01

    The purpose of this study was to investigate how water aging of the resin cement influences the stress distribution in all-ceramic crowns and if there is an increase in the propensity for crown failure. The failure of all-ceramic crowns attributed to cement degradation was explored using a combination of experimental and numerical methods. Sectioned all-ceramic crown specimens were fabricated of IPS e.max Ceram/e.max Press (CP) and Vita VM9/Cercon zirconia (VZ), and then stored in either air or distilled water for 30 days. Monotonic contact loads were applied to fracture near the buccal cusp ridge of each sample. Deformation within the crown layers during loading was analyzed by means of Digital Image Correlation (DIC). A 3D finite element model of the restoration including veneer, core, cement and tooth substrate was developed to evaluate the stress distribution in the crowns before and after cement degradation. There was a significant decrease (p<0.001) in the critical fracture load and a change in the fracture mode after cement water absorption in the CP crowns. In contrast, there was no significant influence of cement aging on fracture modes and fracture loads (p>0.05) in the VZ crowns. Finite element analysis showed that regardless of the crown types, the stress distribution is identical by degradation in Young's modulus of the cement. However, core/substrate debonding results in a change of the stress distribution and a significant increase in the magnitude. Water aging causes reduction of stiffness and bonding strength of cement agents. Degradation in bonding strength and stiffness could potentially lead to stress redistribution in the restored crown and reduce the load-bearing capacity of all-ceramic restorations after years of service.

  15. First Permanent Molar Restoration Differences between Those with or without Dental Sealants.

    ERIC Educational Resources Information Center

    Kuthy, Raymond A.; And Others

    1990-01-01

    The study examined differences in the number of restorations in permanent, posterior teeth for those children receiving dental sealants with cost sharing when compared to children who do not receive sealants. Results indicated a 51 percent reduction in restoration rates for each quadrant sealed. Findings have implications for cost savings and…

  16. Understanding dental CAD/CAM for restorations--the digital workflow from a mechanical engineering viewpoint.

    PubMed

    Tapie, L; Lebon, N; Mawussi, B; Fron Chabouis, H; Duret, F; Attal, J-P

    2015-01-01

    As digital technology infiltrates every area of daily life, including the field of medicine, so it is increasingly being introduced into dental practice. Apart from chairside practice, computer-aided design/computer-aided manufacturing (CAD/CAM) solutions are available for creating inlays, crowns, fixed partial dentures (FPDs), implant abutments, and other dental prostheses. CAD/CAM dental solutions can be considered a chain of digital devices and software for the almost automatic design and creation of dental restorations. However, dentists who want to use the technology often do not have the time or knowledge to understand it. A basic knowledge of the CAD/CAM digital workflow for dental restorations can help dentists to grasp the technology and purchase a CAM/CAM system that meets the needs of their office. This article provides a computer-science and mechanical-engineering approach to the CAD/CAM digital workflow to help dentists understand the technology.

  17. Compressive fatigue limit of four types of dental restorative materials.

    PubMed

    Chen, Song; Öhman, Caroline; Jefferies, Steven R; Gray, Holly; Xia, Wei; Engqvist, Håkan

    2016-08-01

    The purpose of this study was to evaluate the quasi-static compressive strength and the compressive fatigue limit of four different dental restorative materials, before and after aging in distilled water for 30 days. A conventional glass ionomer cement (Fuji IX GP; IG), a zinc-reinforced glass ionomer cement (Chemfil rock; CF), a light curable resin-reinforced glass ionomer cement (Fuji II LC; LC) and a resin-based composite (Quixfil; QF) were investigated. Cylindrical specimens (4mm in diameter and 6mm in height) were prepared according to the manufacturer׳s instructions. The compressive fatigue limit was obtained using the staircase method. Samples were tested in distilled water at 37°C, at a frequency of 10Hz with 10(5) cycles set as run-out. 17 fatigue samples were tested for each group. Two-way ANOVA and one-way ANOVA followed by Tukey׳s post-hoc test were used to analyze the results. Among the four types of materials, the resin-based composite exhibited the highest compressive strength (244±13.0MPa) and compressive fatigue limit (134±7.8MPa), followed by the light-cured resin reinforced glass ionomer cement (168±8.5MPa and 92±6.6MPa, respectively) after one day of storage in distilled water. After being stored for 30 days, all specimens showed an increase in compressive strength. Aging showed no effect on the compressive fatigue limit of the resin-based composite and the light-cured resin reinforced glass ionomer cement, however, the conventional glass ionomer cements showed a drastic decrease (37% for IG, 31% for CF) in compressive fatigue limit. In conclusion, in the present study, resin modified GIC and resin-based composite were found to have superior mechanical properties to conventional GIC.

  18. Complex layered dental restorations: Are they recognizable and do they survive extreme conditions?

    PubMed

    Soon, Alistair S; Bush, Mary A; Bush, Peter J

    2015-09-01

    Recent research has shown that restorative dental materials can be recognized by microscopy and elemental analysis (scanning electron microscopy/energy dispersive X-ray spectroscopy and X-ray fluorescence; SEM/EDS and XRF) and that this is possible even in extreme conditions, such as cremation. These analytical methods and databases of dental materials properties have proven useful in DVI (disaster victim identification) of a commercial plane crash in 2009, and in a number of other victim identification cases. Dental materials appear on the market with ever expanding frequency. With their advent, newer methods of restoration have been proposed and adopted in the dental office. Methods might include placing multiple layers of dental materials, where they have different properties including adhesion, viscosity, or working time. These different dental materials include filled adhesives, flowable resins, glass ionomer cements, composite resins, liners and sealants. With possible combinations of different materials in these restorations, the forensic odontologist is now confronted with a new difficulty; how to recognize each individual material. The question might be posed if it is even possible to perform this task. Furthermore, an odontologist might be called upon to identify a victim under difficult circumstances, such as when presented with fragmented or incinerated remains. In these circumstances the ability to identify specific dental materials could assist in the identification of the deceased. Key to use of this information is whether these new materials and methods are detailed in the dental chart. Visual or radiographic inspection may not reveal the presence of a restoration, let alone the possible complex nature of that restoration. This study demonstrates another scientific method in forensic dental identification.

  19. Urinary levels of nickel and chromium associated with dental restoration by nickel-chromium based alloys.

    PubMed

    Chen, Bo; Xia, Gang; Cao, Xin-Ming; Wang, Jue; Xu, Bi-Yao; Huang, Pu; Chen, Yue; Jiang, Qing-Wu

    2013-03-01

    This paper aims to investigate if the dental restoration of nickel-chromium based alloy (Ni-Cr) leads to the enhanced excretions of Ni and Cr in urine. Seven hundred and ninety-five patients in a dental hospital had single or multiple Ni-Cr alloy restoration recently and 198 controls were recruited to collect information on dental restoration by questionnaire and clinical examination. Urinary concentrations of Ni and Cr from each subject were measure by graphite furnace atomic absorption spectrometry. Compared to the control group, the urinary level of Ni was significantly higher in the patient group of <1 month of the restoration duration, among which higher Ni excretions were found in those with either a higher number of teeth replaced by dental alloys or a higher index of metal crown not covered with the porcelain. Urinary levels of Cr were significantly higher in the three patient groups of <1, 1 to <3 and 3 to <6 months, especially in those with a higher metal crown exposure index. Linear curve estimations showed better relationships between urinary Ni and Cr in patients within 6-month groups. Our data suggested significant increased excretions of urinary Ni and Cr after dental restoration. Potential short- and long-term effects of Ni-Cr alloy restoration need to be investigated.

  20. Effect of dental restorative materials on total antioxidant capacity and calcium concentration of unstimulated saliva

    PubMed Central

    Moghadam, Mona-Momeni; Garcia-Godoy, Franklin; Asatourian, Armen; Aminsobhani, Mohsen; Scarbecz, Mark; Sheibani, Nader

    2017-01-01

    Background To evaluate the effect of dental amalgam and composite restorations on total antioxidant capacity (TAC) and calcium (Ca) ion concentration of unstimulated saliva. Material and Methods Forty-eight children aged 6-10 years selected and divided into three groups of sixteen (8 males, 8 females). In group A and B, samples consisted of two class II dental composite or amalgam restorations, while in group C samples were caries-free (control group). Unstimulated saliva from all samples was collected and TAC was measured by spectrophotometry using an adaptation of 2, 2’-azino-di-(3-ethylbenzthiazoline-6-sulphonate) (ABTS) assay. The Ca ion level was estimated by an auto- analyzer. Data were analyzed with one- and two-way ANOVA test, at a p<.05 level of significance. Results Composite samples showed significantly higher TAC and lower Ca ion levels compared to amalgam and caries-free samples (p<.05). The TAC values showed only significant difference between groups (p<.05), while the Ca ion results showed significant differences within and between groups (p<.05). Conclusions Dental composite restorations increased TAC and decreased Ca ion levels more than amalgam restorations in saliva. Gender is an effective factor in changes induced in oral cavity as females showed more emphatic reaction to dental filling materials than males. Statement of Clinical Relevance Patients who have dental restorations, especially dental composites, should pay more attention to their dental hygiene, because dental restorations can increase oxidative stress and decrease Ca ion level in saliva, which might jeopardize remineralization process of tooth structures after demineralization. Key words:Amalgam, caries, composite, saliva, total antioxidant capacity. PMID:28149467

  1. In Vitro Evaluation and Comparison of the Translucency of Two Different All-Ceramic Systems

    PubMed Central

    Jurišić, Sanja; Jurišić, Gordan

    2015-01-01

    Objectives The aim of this study was to evaluate and compare the translucency of two different all-ceramic systems using Vita Easyshade digital shade matching device in an in vitro model. Materials and methods Translucency of lithium disilicate glass-ceramic (IPS e.max Press) and zirconia all-ceramic system (Ceramill ZI) were evaluated and compared. A total of 5 square-shaped specimens with 0.5 mm thickness were fabricated from each ceramic system in A1 shade according to Vitapan Classical shade tab. Specimens were then veneered and glazed with corresponding veneer ceramics recommended by each system manufacturer and the total thickness was set to 1.5 mm. Translucency was evaluated using VITA Easyshade in two stages: before and after veneering and glazing on black and white background. Translucency parameter (TP) was calculated. A one-way ANOVA and Bonferonni tests were used when appropriate (α=0.05). Results Lithium disilicate glass-ceramic was significantly more translucent than the zirconia system in both stages (P<0.05). Translucency of all specimens was significantly decreased after veneering and glazing in both all-ceramic systems (P<0.05). Conclusion The translucency of two different dental ceramics was significantly influenced by both material and stages of preparation. Within the limitations of the experiment, these results can be valuable and help the clinician to make appropriate esthetic decisions. PMID:27688403

  2. Telescopically retained removable partial dentures on CAD/CAM generated all-ceramic primary telescopes.

    PubMed

    Bär, C; Reich, S

    2008-01-01

    The provision of patients with removable partial dentures on all-ceramic primary crowns with electroplated gold secondary parts is described as an alternative worthy of consideration in dental journals, lectures and in further training courses. The mode of operation is based on a precise, frictionless, passive fit between female and male components. To guarantee this even over large spans, intraoral joining of the individual components is necessary. However, this requires a different sequence of the treatment steps. The different procedures (conventional, procedure by Weigl, modified concept) are described in the following article. Clinical considerations, design principles, and special characteristics involved in producing the partial denture are explained.

  3. Efficient digitalization method for dental restorations using micro-CT data.

    PubMed

    Kim, Changhwan; Baek, Seung Hoon; Lee, Taewon; Go, Jonggun; Kim, Sun Young; Cho, Seungryong

    2017-03-15

    The objective of this study was to demonstrate the feasibility of using micro-CT scan of dental impressions for fabricating dental restorations and to compare the dimensional accuracy of dental models generated from various methods. The key idea of the proposed protocol is that dental impression of patients can be accurately digitized by micro-CT scan and that one can make digital cast model from micro-CT data directly. As air regions of the micro-CT scan data of dental impression are equivalent to the real teeth and surrounding structures, one can segment the air regions and fabricate digital cast model in the STL format out of them. The proposed method was validated by a phantom study using a typodont with prepared teeth. Actual measurement and deviation map analysis were performed after acquiring digital cast models for each restoration methods. Comparisons of the milled restorations were also performed by placing them on the prepared teeth of typodont. The results demonstrated that an efficient fabrication of precise dental restoration is achievable by use of the proposed method.

  4. Efficient digitalization method for dental restorations using micro-CT data

    NASA Astrophysics Data System (ADS)

    Kim, Changhwan; Baek, Seung Hoon; Lee, Taewon; Go, Jonggun; Kim, Sun Young; Cho, Seungryong

    2017-03-01

    The objective of this study was to demonstrate the feasibility of using micro-CT scan of dental impressions for fabricating dental restorations and to compare the dimensional accuracy of dental models generated from various methods. The key idea of the proposed protocol is that dental impression of patients can be accurately digitized by micro-CT scan and that one can make digital cast model from micro-CT data directly. As air regions of the micro-CT scan data of dental impression are equivalent to the real teeth and surrounding structures, one can segment the air regions and fabricate digital cast model in the STL format out of them. The proposed method was validated by a phantom study using a typodont with prepared teeth. Actual measurement and deviation map analysis were performed after acquiring digital cast models for each restoration methods. Comparisons of the milled restorations were also performed by placing them on the prepared teeth of typodont. The results demonstrated that an efficient fabrication of precise dental restoration is achievable by use of the proposed method.

  5. Efficient digitalization method for dental restorations using micro-CT data

    PubMed Central

    Kim, Changhwan; Baek, Seung Hoon; Lee, Taewon; Go, Jonggun; Kim, Sun Young; Cho, Seungryong

    2017-01-01

    The objective of this study was to demonstrate the feasibility of using micro-CT scan of dental impressions for fabricating dental restorations and to compare the dimensional accuracy of dental models generated from various methods. The key idea of the proposed protocol is that dental impression of patients can be accurately digitized by micro-CT scan and that one can make digital cast model from micro-CT data directly. As air regions of the micro-CT scan data of dental impression are equivalent to the real teeth and surrounding structures, one can segment the air regions and fabricate digital cast model in the STL format out of them. The proposed method was validated by a phantom study using a typodont with prepared teeth. Actual measurement and deviation map analysis were performed after acquiring digital cast models for each restoration methods. Comparisons of the milled restorations were also performed by placing them on the prepared teeth of typodont. The results demonstrated that an efficient fabrication of precise dental restoration is achievable by use of the proposed method. PMID:28294188

  6. Trends in material choice for posterior restorations in an Israeli dental school: composite resin versus amalgam.

    PubMed

    Ben-Gal, Gilad; Weiss, Ervin I

    2011-12-01

    According to a recent American Dental Association survey, posterior composite resin restorations now outnumber amalgam restorations in the United States. Dental schools around the world vary considerably in the extent to which they teach the use of composite resins. We aimed to determine if there has been an increase in the placement of posterior composite restorations in an Israeli dental school and if faculty experience affects the type of posterior restoration placed. In this retrospective study, we recorded and analyzed all the restorations performed by undergraduate students in the last five academic years at the Hebrew University Hadassah School of Dental Medicine in Jerusalem. All clinical records of student treatments between 2004 and 2009 were screened, and direct restorations were registered. Out of 6,094 posterior restorations performed during the study period, 42.3 percent were made of composite resin, increasing from 36.8 percent in 2004-05 to 48.5 percent in 2008-09, an increase of 11.7 percent. When clinical instructors were asked to state their preference if they themselves were to undergo posterior restoration, similar results were obtained. Instructors with less than ten years' experience preferred posterior composite resin restorations in 54.8 percent of the hypothetical situations, compared with 37.2 percent preferred by instructors with ten years of experience or more. It appears that the use of composite resin was influenced mainly by the prevailing trend and was not based on scientific evidence. Dental faculties should define criteria, based on up-to-date clinical studies, for using new materials, taking into consideration differences among instructors regarding treatment concept.

  7. Synchrotron-radiation-based X-ray micro-computed tomography reveals dental bur debris under dental composite restorations.

    PubMed

    Hedayat, Assem; Nagy, Nicole; Packota, Garnet; Monteith, Judy; Allen, Darcy; Wysokinski, Tomasz; Zhu, Ning

    2016-05-01

    Dental burs are used extensively in dentistry to mechanically prepare tooth structures for restorations (fillings), yet little has been reported on the bur debris left behind in the teeth, and whether it poses potential health risks to patients. Here it is aimed to image dental bur debris under dental fillings, and allude to the potential health hazards that can be caused by this debris when left in direct contact with the biological surroundings, specifically when the debris is made of a non-biocompatible material. Non-destructive micro-computed tomography using the BioMedical Imaging & Therapy facility 05ID-2 beamline at the Canadian Light Source was pursued at 50 keV and at a pixel size of 4 µm to image dental bur fragments under a composite resin dental filling. The bur's cutting edges that produced the fragment were also chemically analyzed. The technique revealed dental bur fragments of different sizes in different locations on the floor of the prepared surface of the teeth and under the filling, which places them in direct contact with the dentinal tubules and the dentinal fluid circulating within them. Dispersive X-ray spectroscopy elemental analysis of the dental bur edges revealed that the fragments are made of tungsten carbide-cobalt, which is bio-incompatible.

  8. Does atraumatic restorative treatment reduce dental anxiety in children? A systematic review and meta-analysis

    PubMed Central

    Simon, Arun K.; Bhumika, T. V.; Nair, N. Sreekumaran

    2015-01-01

    Dental anxiety is one of the major problems affecting children, which impairs the rendering of dental care, leading to impaired quality of life. It often leads to occupational stress in dental personnel and conflict between parents/caregivers. The objective of this study was to conduct a systematic review and meta-analysis of randomized controlled trials done in children, to synthesize evidence of the effectiveness of atraumatic restorative treatment (ART) in reducing dental anxiety in children compared to conventional restorative treatments. The databases searched included PubMed, Google Scholar and The Cochrane Oral Health Group's Trials Register. Eligible studies reporting dental anxiety by a variety of psychometric scales were tabulated. The review was conducted and reported in accordance with the guidelines provided by the Cochrane Collaboration. Among 416 studies retrieved through literature search, six studies matched the inclusion criteria. Due to lack of data, only three studies were included for meta-analysis using RevMan software (Review Manager, Version 5.3;The Cochrane Collaboration, Copenhagen, 2014). The pooled meta-analysis data, (standardized mean difference − 2.12 [95% confidence interval: −4.52, 0.27]) failed to show any difference between ART group and the conventional treatment group. In conclusion, ART was not more beneficial in reducing dental anxiety among pediatric dental patients. The findings are relevant in the field of clinical practice in dentistry in the management of the anxious pediatric dental patient. PMID:26038668

  9. Amino acid derivative-mediated detoxification and functionalization of dual cure dental restorative material for dental pulp cell mineralization.

    PubMed

    Minamikawa, Hajime; Yamada, Masahiro; Iwasa, Fuminori; Ueno, Takeshi; Deyama, Yoshiaki; Suzuki, Kuniaki; Yawaka, Yasutaka; Ogawa, Takahiro

    2010-10-01

    Current dental restorative materials are only used to fill the defect of hard tissues, such as dentin and enamel, because of their cytotoxicity. Therefore, exposed dental pulp tissues in deep cavities must be first covered by a pulp capping material like calcium hydroxide to form a layer of mineralized tissue. However, this tissue mineralization is based on pathological reaction and triggers long-lasting inflammation, often causing clinical problems. This study tested the ability of N-acetyl cysteine (NAC), amino acid derivative, to reduce cytotoxicity and induce mineralized tissue conductivity in resin-modified glass ionomer (RMGI), a widely used dental restorative material having dual cure mechanism. Rat dental pulp cells were cultured on untreated or NAC-supplemented RMGI. NAC supplementation substantially increased the percentage of viable cells from 46.7 to 73.3% after 24-h incubation. Cell attachment, spreading, proliferative activity, and odontoblast-related gene and protein expressions increased significantly on NAC-supplemented RMGI. The mineralization capability of cells, which was nearly suppressed on untreated RMGI, was induced on NAC-supplemented RMGI. These improved behaviors and functions of dental pulp cells on NAC-supplemented RMGI were associated with a considerable reduction in the production of intracellular reactive oxygen species and with the increased level of intracellular glutathione reserves. These results demonstrated that NAC could detoxify and functionalize RMGIs via two different mechanisms involving in situ material detoxification and antioxidant cell protection. We believe that this study provides a new approach for developing dental restorative materials that enables mineralized tissue regeneration.

  10. Amalgam and composite posterior restorations: curriculum versus practice in operative dentistry at a US dental school.

    PubMed

    Ottenga, Marc E; Mjör, Ivar

    2007-01-01

    This study recorded the number of preclinical lecture and simulation laboratory sessions spent teaching the preparation and placement of amalgam and resin composite posterior restorations. These data were compared to the use of both materials in the operative clinic as placed by third- and fourth-year students. The number of posterior restorations inserted by the students, expressed as a function of the number of restoration surfaces, was also evaluated. The results show that the teaching of posterior restorations pre-clinically has consistently favored amalgam 2.5 to 1 during the last three years. However, clinically, resin composite is being used for posterior restorations 2.3 times more often than amalgam. The only instance that favored amalgam over composite during the last year was in the placement of four surface posterior restorations. This shift in emphasis from amalgam to composite needs to be addressed within dental educational institutions so that newly graduated dentists are prepared to place composite restorations properly.

  11. Understanding dental CAD/CAM for restorations--accuracy from a mechanical engineering viewpoint.

    PubMed

    Tapie, Laurent; Lebon, Nicolas; Mawussi, Bernardin; Fron-Chabouis, Hélène; Duret, Francois; Attal, Jean-Pierre

    2015-01-01

    As is the case in the field of medicine, as well as in most areas of daily life, digital technology is increasingly being introduced into dental practice. Computer-aided design/ computer-aided manufacturing (CAD/CAM) solutions are available not only for chairside practice but also for creating inlays, crowns, fixed partial dentures (FPDs), implant abutments, and other dental prostheses. CAD/CAM dental practice can be considered as the handling of devices and software processing for the almost automatic design and creation of dental restorations. However, dentists who want to use dental CAD/CAM systems often do not have enough information to understand the variations offered by such technology practice. Knowledge of the random and systematic errors in accuracy with CAD/CAM systems can help to achieve successful restorations with this technology, and help with the purchasing of a CAD/CAM system that meets the clinical needs of restoration. This article provides a mechanical engineering viewpoint of the accuracy of CAD/ CAM systems, to help dentists understand the impact of this technology on restoration accuracy.

  12. Fluoride release and recharge abilities of contemporary fluoride-containing restorative materials and dental adhesives.

    PubMed

    Dionysopoulos, Dimitrios; Koliniotou-Koumpia, Eugenia; Helvatzoglou-Antoniades, Maria; Kotsanos, Nikolaos

    2013-01-01

    The aim of this study was to evaluate the fluoride release of five fluoride-releasing restorative materials and three dental adhesives, before and after NaF solution treatment. Five restorative materials (Fuji IX GP, GC Corp.; Ketac N100, 3M ESPE; Dyract Extra, Dentsply; Beautifil II, Shofu Inc.; Wave, SDI) and three dental adhesives (Stae, SDI; Fluorobond II - Shofu Inc.; Prime & Bond NT, Dentsply) were investigated before and after NaF solution treatment. A fluoride ion-selective electrode was to measure fluoride concentrations. During the 86-day period before NaF solution treatment, Fuji IX GP released the highest amount of fluoride among the restorative materials while Prime & Bond NT was the highest among the dental adhesives. After NaF solution treatment, Fuji IX GP again ranked the highest in fluoride release among the restorative materials while Fluorobond II ranked the highest among dental adhesives. It was concluded that the compositions and setting mechanisms of fluoride-containing dental materials influenced their fluoride release and recharge abilities.

  13. Optimal restoration of dental esthetics and function with advanced implant-supported prostheses: a clinical report.

    PubMed

    Meulen, Peter van der; Linden, Wynand van der; Eeden, Ronnie van

    2012-07-01

    For more than 25 years, computer-aided design and computer-aided manufacturing (CAD/CAM) technology has been used in implant restorative dentistry. Today this technology offers a means of milling titanium frameworks that fit dental implants accurately. This report presents a restoratively driven protocol employing advanced implant restorative and surgical techniques. Treatment of a patient with advanced periodontitis with extensive loss of hard and soft tissues is presented. After extraction of the patient's remaining hopeless teeth, dental implants were placed, along with interim, fixed-margin abutments and abutment protection caps. Two days later, acrylic resin fixed-interim prostheses restored the patient's esthetics and partial masticatory function. After implant osseointegration, maxillary, and mandibular frameworks for definitive prostheses were milled from Ti alloy, using one specific CAD/CAM technology. The benefits of this technology are also discussed.

  14. A Comparison of US and Japanese Dental Restorative Care Present on Service Members Recovered from the WWII Era.

    PubMed

    Shiroma, Calvin Y

    2017-02-20

    The documentation of dental materials used in the USA during the WWII era is readily available, while references for the Japanese are minimal. It was therefore important to build a photographic database of Japanese restorative care which could be utilized as a comparison tool for the deployed odontologist. The dental restorative care of approximately 400 US and 100 Japanese sets of remains was evaluated. Both countries share many similar restorative techniques to include collared crowns, full-coverage restorations, cantilever bridge/pontics to close spaces; restorative materials such as amalgam, gold, and zinc phosphate (temporary) restorations; and removable prostheses. The dental restorative materials most commonly used by US dentists include the amalgam and silicate cement, while the full-coverage crown was the type of restoration most frequently seen on the Japanese remains. Silicates, porcelain and replaceable crowns, and partial-coverage prepared crowns were not observed on the recovered Japanese remains.

  15. Discrimination of tooth layers and dental restorative materials using cutting sounds.

    PubMed

    Zakeri, Vahid; Arzanpour, Siamak; Chehroudi, Babak

    2015-03-01

    Dental restoration begins with removing carries and affected tissues with air-turbine rotary cutting handpieces, and later restoring the lost tissues with appropriate restorative materials to retain the functionality. Most restoration materials eventually fail as they age and need to be replaced. One of the difficulties in replacing failing restorations is discerning the boundary of restorative materials, which causes inadvertent removal of healthy tooth layers. Developing an objective and sensor-based method is a promising approach to monitor dental restorative operations and to prevent excessive tooth losses. This paper has analyzed cutting sounds of an air-turbine handpiece to discriminate between tooth layers and two commonly used restorative materials, amalgam and composite. Support vector machines were employed for classification, and the averaged short-time Fourier transform coefficients were selected as the features. The classifier performance was evaluated from different aspects such as the number of features, feature scaling methods, classification schemes, and utilized kernels. The total classification accuracies were 89% and 92% for cases included composite and amalgam materials, respectively. The obtained results indicated the feasibility and effectiveness of the proposed method.

  16. Inequalities in preventive and restorative dental services in England, Wales and Northern Ireland.

    PubMed

    Cheema, J; Sabbah, W

    2016-09-09

    Aims The objective of this study is to assess socioeconomic inequalities in the use of selected dental procedures.Methods Data is from the Adult Dental Health Survey 2009, a nationally representative cross-sectional survey of England, Northern Ireland and Wales. Overall, 6,279 participants were included in the analysis. Occupational classification and education were used to assess variations in the use of preventive, restorative services and tooth extraction using a series of logistic regression models, adjusting for age, sex, ethnicity, DMFT, self-reported oral health, dental visits and country.Results There were clear socioeconomic variations in the utilisation of preventive and restorative services. In the fully adjusted model those with no educational qualification were less likely to report ever having preventive services than those with a degree (OR 0.48, 95%CI: 0.36,0.65). Similarly, individuals in routine/manual occupation were significantly less likely to report ever having preventive services than those in managerial/professional occupation (OR 0.58, 95%CI: 0.46,0.74) in the fully adjusted model.Conclusion The findings imply that despite relatively equitable access and higher use of dental services in UK, the least educated and those at the bottom of social hierarchy are less likely to have preventive and restorative dental services.

  17. Monoenergetic computed tomography reconstructions reduce beam hardening artifacts from dental restorations.

    PubMed

    Stolzmann, Paul; Winklhofer, Sebastian; Schwendener, Nicole; Alkadhi, Hatem; Thali, Michael J; Ruder, Thomas D

    2013-09-01

    The aim of this study was to assess the potential of monoenergetic computed tomography (CT) images to reduce beam hardening artifacts in comparison to standard CT images of dental restoration on dental post-mortem CT (PMCT). Thirty human decedents (15 male, 58 ± 22 years) with dental restorations were examined using standard single-energy CT (SECT) and dual-energy CT (DECT). DECT data were used to generate monoenergetic CT images, reflecting the X-ray attenuation at energy levels of 64, 69, 88 keV, and at an individually adjusted optimal energy level called OPTkeV. Artifact reduction and image quality of SECT and monoenergetic CT were assessed objectively and subjectively by two blinded readers. Subjectively, beam artifacts decreased visibly in 28/30 cases after monoenergetic CT reconstruction. Inter- and intra-reader agreement was good (k = 0.72, and k = 0.73 respectively). Beam hardening artifacts decreased significantly with increasing monoenergies (repeated-measures ANOVA p < 0.001). Artifact reduction was greatest on monoenergetic CT images at OPTkeV. Mean OPTkeV was 108 ± 17 keV. OPTkeV yielded the lowest difference between CT numbers of streak artifacts and reference tissues (-163 HU). Monoenergetic CT reconstructions significantly reduce beam hardening artifacts from dental restorations and improve image quality of post-mortem dental CT.

  18. Genotoxicity evaluation of dental restoration nanocomposite using comet assay and chromosome aberration test

    NASA Astrophysics Data System (ADS)

    Musa, Marahaini; Thirumulu Ponnuraj, Kannan; Mohamad, Dasmawati; Rahman, Ismail Ab

    2013-01-01

    Nanocomposite is used as a dental filling to restore the affected tooth, especially in dental caries. The dental nanocomposite (KelFil) for tooth restoration used in this study was produced by the School of Dental Sciences, Universiti Sains Malaysia, Malaysia and is incorporated with monodispersed, spherical nanosilica fillers. The aim of the study was to determine the genotoxic effect of KelFil using in vitro genotoxicity tests. The cytotoxicity and genotoxicity of KelFil was evaluated using MTT assay, comet assay and chromosome aberration tests with or without the addition of a metabolic activation system (S9 mix), using the human lung fibroblast cell line (MRC-5). Concurrent negative and positive controls were included. In the comet assay, no comet formation was found in the KelFil groups. There was a significant difference in tail moment between KelFil groups and positive control (p < 0.05). Similarly, no significant aberrations in chromosomes were noticed in KelFil groups. The mitotic indices of treatment groups and negative control were significantly different from positive controls. Hence, it can be concluded that the locally produced dental restoration nanocomposite (KelFil) is non-genotoxic under the present test conditions.

  19. ClinicAl Evaluation of Dental Restorative Materials

    DTIC Science & Technology

    1989-01-01

    and strength of the restoration to resist flexural occlusal stresses and acts as a secondary cause for fracture. Wear together with fracture...caries, accounting for 39.9 percent of failures. Wear further decreases the bulk and strength of the restoration to resist flexural occlusal stresses ...Machining of the surface during the finishing and polishing procedure may produce microdefects and/or residual stress in the surface which would

  20. Microleakage of Er:YAG laser and dental bur prepared cavities in primary teeth restored with different adhesive restorative materials.

    PubMed

    Baghalian, Ali; Nakhjavani, Yahya B; Hooshmand, Tabassom; Motahhary, Pouria; Bahramian, Hoda

    2013-11-01

    The purpose of this study was to evaluate and compare the effect of erbium:yttrium-aluminum-garnet (Er:YAG) laser irradiation and conventional dental bur cavity preparation on in vitro microleakage of class V cavities restored with different adhesive restorative materials and two types of self-etching adhesives in primary teeth. Standard class V cavities were prepared on 80 extracted primary, and the teeth were randomly divided into eight subgroups prepared either by dental bur or Er:YAG laser irradiation and then restored with self-cured glass ionomer (GI), resin-modified glass ionomer (RMGI), resin composite and Clearfil SE Bond (two-step self-etching adhesive), and resin composite and Clearfil S3 Bond (one-step self-etching adhesive). Restorations were finished and stored in distilled water at 37 °C for 24 h and then subjected to thermocycling. All the teeth were sealed with nail varnish, placed in a silver nitrate solution, and then vertically cut in a buccolingually direction. Subsequently, the specimens were evaluated for gingival and occlusal microleakage using a stereomicroscope. Data were analyzed using Kruskal-Wallis test followed by Mann-Whitney test. Wilcoxon test was used for comparing occlusal microleakage with gingival microleakage at p < 0.05. A higher degree of occlusal and gingival microleakage values for the teeth restored with GI or RMGI was obtained by both preparation methods compared with that of resin composites and the two self-etching primers. Er:YAG laser irradiation resulted in a significantly higher degree of microleakage only at the gingival margins for teeth restored with GI or RMGI, or composite and Clearfil S3 Bond compared with the bur preparation. The Er:YAG laser-prepared teeth restored with composite and Clearfil SE Bond demonstrated a better marginal seal on occlusal and gingival margins compared with that of bur-prepared cavities. The degree of microleakage in class V cavities was affected by the type of adhesive

  1. Quantification of Staphylococcus aureus adhesion forces on various dental restorative materials using atomic force microscopy

    NASA Astrophysics Data System (ADS)

    Merghni, Abderrahmen; Kammoun, Dorra; Hentati, Hajer; Janel, Sébastien; Popoff, Michka; Lafont, Frank; Aouni, Mahjoub; Mastouri, Maha

    2016-08-01

    In the oral cavity dental restorative biomaterials can act as a reservoir for infection with opportunistic Staphylococcus aureus pathogen, which can lead to the occurrence of secondary caries and treatment failures. Our aim was to evaluate the adhesion forces by S. aureus on four dental restorative biomaterials and to correlate this finding to differences in specific surface characteristics. Additionally, the influence of salivary conditioning films in exerted adhesion forces was investigated. The substrate hydrophobicity was measured by goniometer and the surface free energy was calculated using the equilibrium advancing contact angle values of water, formamide, and diiodomethane on the tested surfaces. The surface roughness was determined using atomic force microscope (AFM). Additionally, cell force spectroscopy was achieved to quantify the forces that drive cell-substrate interactions. S. aureus bacterium exerted a considerable adhesion forces on various dental restorative materials, which decreased in the presence of saliva conditioning film. The influence of the surface roughness and free energy in initial adhesion appears to be more important than the effect of hydrophobicity, either in presence or absence of saliva coating. Hence, control of surface properties of dental restorative biomaterials is of crucial importance in preventing the attachment and subsequent the biofilm formation.

  2. Color Stability of Dental Restorative Materials Submitted to Heat Sources, for Forensic Purposes.

    PubMed

    Biancalana, Roberto Cesar; Vicente, Sergio Augusto de Freitas; Alves da Silva, Ricardo Henrique; Pires-de-Souza, Fernanda de Carvalho Panzeri

    2017-03-01

    During postmortem examination of the dental arches of carbonized victims, dental restorative materials may be found. The aim of this study was to evaluate the effect of heat source action on the color stability of composite resin (CR) and glass ionomer cement (GIC) restorations, to discriminate between them and compare with antemortem dental data. Sixty bovine teeth (30 CR and 30 GIC) were prepared (6 × 6 × 2 mm) and separated into groups (n = 10). The color readouts were taken by spectrophotometer, before and after heat action (100°C, 200°C, 300°C), in an oven for 15 min. There were color alterations for all coordinates (ΔE, ΔL*, Δa* eΔb*) for both materials. GIC presented greater change. The authors concluded that it is possible to distinguish between the materials by the color changes analyzed by instrumental method, helping victim identification.

  3. Mechanical benefits of conservative restoration for dental fissure caries.

    PubMed

    Zhang, Zhongpu; Zheng, Keke; Li, Eric; Li, Wei; Li, Qing; Swain, Michael V

    2016-01-01

    The principle of minimal intervention dentistry (MID) is to limit removal of carious tooth tissue while maximizing its repair and survival potential. The objective of this study is to explore the fracture resistance of a permanent molar tooth with a fissure carious lesion along with three clinical restoration procedures, namely one traditional and two conservative approaches, based upon MID. The traditional restoration employs extensive surgical removal of enamel and dentine about the cavity to eliminate potential risk of further caries development, while conservative method #1 removes significantly less enamel and infected dentine, and conservative method #2 only restores the overhanging enamel above the cavity and leaves the infected and affected dentine as it was. An extended finite element method (XFEM) is adopted here to analyze the fracture behaviors of both two-dimensional (2D) and three-dimensional (3D) modeling of these four different scenarios. It was found that the two conservative methods exhibited better fracture resistance than the traditional restorative method. Although conservative method #2 has less fracture resistance than method #1, it had significantly superior fracture resistance compared to other restorations. More important, after cavity sealing it may potentially enhance the opportunity for remineralization and improved loading bearing capacity and fracture resistance.

  4. Concordance between Responses to Questionnaire Scenarios and Actual Treatment to Repair or Replace Dental Restorations in the National Dental PBRN

    PubMed Central

    Heaven, Tim J.; Gordan, Valeria V.; Litaker, Mark S.; Fellows, Jeffrey L.; Rindal, D. Brad; Gilbert, Gregg H.

    2015-01-01

    Objective To quantify the agreement between treatment recommended during hypothetical clinical scenarios and actual treatment provided in comparable clinical circumstances. Methods A total of 193 practitioners in the National Dental Practice-Based Research Network participated in both a questionnaire and a clinical study. The questionnaire included three hypothetical scenarios about treatment of existing restorations. Clinicians then participated in a clinical study about repair or replacement of existing restorations. We quantified the overall concordance between their questionnaire responses and what they did in actual clinical treatment. Results Practitioners who recommended repair (instead of replacement) of more scenario restorations also had higher repair percentages in clinical practice. Additionally, for each of the three hypothetical scenario restorations, practitioners who recommended repair had higher repair percentages in clinical practice. Conclusions The questionnaire scenarios were a valid measure of clinicians’ tendency to repair or replace restorations in actual clinical practice. Clinical implications Although there was substantial variation in practitioners’ tendency to repair or replace restorations, responses to questionnaire scenarios by individual practitioners were concordant with what they did in actual clinical practice. PMID:25998565

  5. Micro-CT evaluation of the marginal fit of CAD/CAM all ceramic crowns

    NASA Astrophysics Data System (ADS)

    Brenes, Christian

    Objectives: Evaluate the marginal fit of CAD/CAM all ceramic crowns made from lithium disilicate and zirconia using two different fabrication protocols (model and model-less). METHODS: Forty anterior all ceramic restorations (20 lithium disilicate, 20 zirconia) were fabricated using a CEREC Bluecam scanner. Two different fabrication methods were used: a full digital approach and a printed model. Completed crowns were cemented and marginal gap was evaluated using Micro-CT. Each specimen was analyzed in sagittal and trans-axial orientations, allowing a 360° evaluation of the vertical and horizontal fit. RESULTS: Vertical measurements in the lingual, distal and mesial views had and estimated marginal gap from 101.9 to 133.9 microns for E-max crowns and 126.4 to 165.4 microns for zirconia. No significant differences were found between model and model-less techniques. CONCLUSION: Lithium disilicate restorations exhibited a more accurate and consistent marginal adaptation when compared to zirconia crowns. No statistically significant differences were observed when comparing model or model-less approaches.

  6. Effects of high temperature on different restorations in forensic identification: Dental samples and mandible

    PubMed Central

    Patidar, Kalpana A; Parwani, Rajkumar; Wanjari, Sangeeta

    2010-01-01

    Introduction: The forensic odontologist strives to utilize the charred human dentition throughout each stage of dental evaluation, and restorations are as unique as fingerprints and their radiographic morphology as well as the types of filling materials are often the main feature for identification. The knowledge of detecting residual restorative material and composition of unrecovered adjacent restoration is a valuable tool-mark in the presumptive identification of the dentition of a burned victim. Gold, silver amalgam, silicate restoration, and so on, have a different resistance to prolonged high temperature, therefore, the identification of burned bodies can be correlated with adequate qualities and quantities of the traces. Most of the dental examination relies heavily on the presence of the restoration as well as the relationship of one dental structure to another. This greatly narrows the research for the final identification that is based on postmortem data. Aim: The purpose of this study is to examine the resistance of teeth and different restorative materials, and the mandible, to variable temperature and duration, for the purpose of identification. Materials and Methods: The study was conducted on 72 extracted teeth which were divided into six goups of 12 teeth each based on the type of restorative material. (Group 1 - unrestored teeth, group 2 - teeth restored with Zn3(PO4)2, group 3 - with silver amalgam, group 4 with glass ionomer cement, group 5 - Ni-Cr-metal crown, group 6 - metal ceramic crown) and two specimens of the mandible. The effect of incineration at 400°C (5 mins, 15 mins, 30 mins) and 1100°C (15 mins) was studied. Results: Damage to the teeth subjected to variable temperatures and time can be categorized as intact (no damage), scorched (superficially parched and discolored), charred (reduced to carbon by incomplete combustion) and incinerated (burned to ashes). PMID:21189989

  7. Influence of the supporting die structures on the fracture strength of all-ceramic materials.

    PubMed

    Yucel, Munir Tolga; Yondem, Isa; Aykent, Filiz; Eraslan, Oğuz

    2012-08-01

    This study investigated the influence of the elastic modulus of supporting dies on the fracture strengths of all-ceramic materials used in dental crowns. Four different types of supporting die materials (dentin, epoxy resin, brass, and stainless steel) (24 per group) were prepared using a milling machine to simulate a mandibular molar all-ceramic core preparation. A total number of 96 zirconia cores were fabricated using a CAD/CAM system. The specimens were divided into two groups. In the first group, cores were cemented to substructures using a dual-cure resin cement. In the second group, cores were not cemented to the supporting dies. The specimens were loaded using a universal testing machine at a crosshead speed of 0.5 mm/min until fracture occurred. Data were statistically analyzed using two-way analysis of variance and Tukey HSD tests (α = 0.05). The geometric models of cores and supporting die materials were developed using finite element method to obtain the stress distribution of the forces. Cemented groups showed statistically higher fracture strength values than non-cemented groups. While ceramic cores on stainless steel dies showed the highest fracture strength values, ceramic cores on dentin dies showed the lowest fracture strength values among the groups. The elastic modulus of the supporting die structure is a significant factor in determining the fracture resistance of all-ceramic crowns. Using supporting die structures that have a low elastic modulus may be suitable for fracture strength tests, in order to accurately reflect clinical conditions.

  8. Utilizing optical coherence tomography for CAD/CAM of indirect dental restorations

    NASA Astrophysics Data System (ADS)

    Chityala, Ravishankar; Vidal, Carola; Jones, Robert

    Optical Coherence Tomography (OCT) has seen broad application in dentistry including early carious lesion detection and imaging defects in resin composite restorations. This study investigates expanding the clinical usefulness by investigating methods to use OCT for obtaining three-dimensional (3D) digital impressions, which can be integrated to CAD/CAM manufacturing of indirect restorations. 3D surface topography `before' and `after' a cavity preparation was acquired by an intraoral cross polarization swept source OCT (CP-OCT) system with a Micro-Electro-Mechanical System (MEMS) scanning mirror. Image registration and segmentation methods were used to digitally construct a replacement restoration that modeled the original surface morphology of a hydroxyapatite sample. After high resolution additive manufacturing (e.g. polymer 3D printing) of the replacement restoration, micro-CT imaging was performed to examine the marginal adaptation. This study establishes the protocol for further investigation of integrating OCT with CAD/CAM of indirect dental restorations.

  9. Cytogenetic genotoxic investigation in peripheral blood lymphocytes of subjects with dental composite restorative filling materials.

    PubMed

    Pettini, F; Savino, M; Corsalini, M; Cantore, S; Ballini, A

    2015-01-01

    Dental composite resins are biomaterials commonly used to aesthetically restore the structure and function of teeth impaired by caries, erosion, or fracture. Residual monomers released from resin restorations as a result of incomplete polymerization processes interact with living oral tissues. The objective of this study was to evaluate the genotoxicity of a common dental composite material (Enamel Plus-HFO), in subjects with average 13 filled teeth with the same material, compared to a control group (subjects having neither amalgam nor composite resin fillings). Genotoxicity assessment of composite materials was carried out in vitro in human peripheral blood leukocytes using sister-chromatid exchange (SCE) and chromosomal aberrations (CA) cytogenetic tests. The results of correlation and multiple regression analyses confirmed the absence of a relationship between SCE/cell, high frequency of SCE(HFC) or CA frequencies and exposure to dental composite materials. These results indicate that composite resins used for dental restorations differ extensively in vivo in their cytotoxic and genotoxic potential and in their ability to affect chromosomal integrity, cell-cycle progression, DNA replication and repair.

  10. An update on glass fiber dental restorative composites: a systematic review.

    PubMed

    Khan, Abdul Samad; Azam, Maria Tahir; Khan, Maria; Mian, Salman Aziz; Ur Rehman, Ihtesham

    2015-02-01

    Dentistry is a much developed field in the last few decades. New techniques have changed the conventional treatment methods as applications of new dental materials give better outcomes. The current century has suddenly forced on dentistry, a new paradigm regarding expected standards for state-of-the-art patient care. Within the field of restorative dentistry, the incredible advances in dental materials research have led to the current availability of esthetic adhesive restorations. The chemistry and structure of the resins and the nature of the glass fiber reinforced systems in dental composites are reviewed in relation to their influence and properties including mechanical, physical, thermal, biocompatibility, technique sensitivity, mode and rate of failure of restorations on clinical application. It is clear that a deeper understanding of the structure of the polymeric matrix and resin-based dental composite is required. As a result of ongoing research in the area of glass fiber reinforced composites and with the development and advancement of these composites, the future prospects of resin-based composite are encouraging.

  11. Determination of light elements in amalgam restorations. [Dental amalgam

    SciTech Connect

    Hanson, A.L.; Jones, K.W.; Kraner, H.W.; Osborne, J.W.; Nelson, G.V.

    1982-01-01

    Rutherford backscattering has been used to measure the major elemental compositions in the near-surface regions of freshly prepared and used samples of dental amalgam. A depletion from bulk stoichiometry of the major elements, which indicates an accumulation of lighter elements on the surface of the materials, has been observed. Increases in the F, Na, Cl, P, O, C, and N concentrations between freshly prepared samples and used samples were measured by observation of gamma rays produced by proton and deuteron induced reactions.

  12. Determination of optical properties in dental restorative biomaterials using the inverse-adding-doubling method

    NASA Astrophysics Data System (ADS)

    Fernández-Oliveras, Alicia; Rubiño, Manuel; Pérez, María. M.

    2013-11-01

    Light propagation in biological media is characterized by the absorption coefficient, the scattering coefficient, the scattering phase function, the refractive index, and the surface conditions (roughness). By means of the inverse-adding-doubling (IAD) method, transmittance and reflectance measurements lead to the determination of the absorption coefficient and the reduced scattering coefficient. The additional measurement of the phase function performed by goniometry allows the separation of the reduced scattering coefficient into the scattering coefficient and the scattering anisotropy factor. The majority of techniques, such as the one utilized in this work, involve the use of integrating spheres to measure total transmission and reflection. We have employed an integrating sphere setup to measure the total transmittance and reflectance of dental biomaterials used in restorative dentistry. Dental biomaterials are meant to replace dental tissues, such as enamel and dentine, in irreversibly diseased teeth. In previous works we performed goniometric measurements in order to evaluate the scattering anisotropy factor for these kinds of materials. In the present work we have used the IAD method to combine the measurements performed using the integrating sphere setup with the results of the previous goniometric measurements. The aim was to optically characterize the dental biomaterials analyzed, since whole studies to assess the appropriate material properties are required in medical applications. In this context, complete optical characterizations play an important role in achieving the fulfillment of optimal quality and the final success of dental biomaterials used in restorative dentistry.

  13. Modelling the Longevity of Dental Restorations by means of a CBR System

    PubMed Central

    Aliaga, Ignacio J.; Vera, Vicente; García, Alvaro E.

    2015-01-01

    The lifespan of dental restorations is limited. Longevity depends on the material used and the different characteristics of the dental piece. However, it is not always the case that the best and longest lasting material is used since patients may prefer different treatments according to how noticeable the material is. Over the last 100 years, the most commonly used material has been silver amalgam, which, while very durable, is somewhat aesthetically displeasing. Our study is based on the collection of data from the charts, notes, and radiographic information of restorative treatments performed by Dr. Vera in 1993, the analysis of the information by computer artificial intelligence to determine the most appropriate restoration, and the monitoring of the evolution of the dental restoration. The data will be treated confidentially according to the Organic Law 15/1999 on 13 December on the Protection of Personal Data. This paper also presents a clustering technique capable of identifying the most significant cases with which to instantiate the case-base. In order to classify the cases, a mixture of experts is used which incorporates a Bayesian network and a multilayer perceptron; the combination of both classifiers is performed with a neural network. PMID:25866792

  14. Testing adhesion of direct restoratives to dental hard tissue - a review.

    PubMed

    Salz, Ulrich; Bock, Thorsten

    2010-10-01

    This articles concerns itself with the testing of adhesion between direct restoratives and dental hard tissue, ie, enamel and dentin. The aim is to survey available methods for adhesion testing and influential parameters affecting experimental outcome. The testing of adhesion to indirect restorative materials, eg, ceramics and metals, is beyond the scope of this article and shall be discussed elsewhere. The longevity and success of modern dental restorations very often relies on potent dental adhesives to provide durable bonds between the dental hard substance and the restorative composite. To predict the clinical outcome of such restorative treatment, a large variety of in vitro laboratory tests and clinical in vivo experiments have been devised, analyzed, and published. The purpose of this review is to provide a current overview of bond strength testing methods and their applicability to the characterization of dental adhesives. Regardless of the method employed, subtle variations in sample preparation may already severely impact test results, usually necessitating at least co-testing of a well-known internal reference to allow conclusive interpretation. This article attempts to list and discuss the most influential parameters, such as substrate nature, age, health status, storage, clinically relevant pre-treatment, and sample preparation. Special attention is devoted to the last aspect, as numerous publications have stressed the tremendous influence of preparatory parameters on the validity and scope of obtained data. Added to the large variety of such factors, an equally large diversity of load-applying procedures exists to actually quantify adhesion between composites and dental hard substance. This article summarizes the basics of macro and micro approaches to shear and tensile bond strength testing, as well as push- and pull-out tests. The strengths and weaknesses inherent to each method and influential test parameters are reviewed and methods for

  15. All ceramic structure for molten carbonate fuel cell

    DOEpatents

    Smith, James L.; Kucera, Eugenia H.

    1992-01-01

    An all-ceramic molten carbonate fuel cell having a composition formed of a multivalent metal oxide or oxygenate such as an alkali metal, transition metal oxygenate. The structure includes an anode and cathode separated by an electronically conductive interconnect. The electrodes and interconnect are compositions ceramic materials. Various combinations of ceramic compositions for the anode, cathode and interconnect are disclosed. The fuel cell exhibits stability in the fuel gas and oxidizing environments. It presents reduced sealing and expansion problems in fabrication and has improved long-term corrosion resistance.

  16. Repair or replacement of restorations: a prospective cohort study by dentists in The National Dental PBRN

    PubMed Central

    Gordan, Valeria V.; Riley, Joseph L.; Rindal, D. Brad; Qvist, Vibeke; Fellows, Jeffrey L.; Dilbone, Deborah A.; Brotman, Solomon G.; Gilbert, Gregg H.

    2015-01-01

    OBJECTIVES (1) quantify 12-month failures of restorations that were repaired or replaced at baseline; (2) test the hypothesis that no significant differences exist in failure percentages between repaired and replaced restorations after 12 months; (3) test the hypothesis that certain dentist’s, patient’s and restoration’s characteristics are significantly associated with the incidence of restoration failure. METHODS This prospective cohort study included dentists in the National Dental Practice-Based Research Network. Dentists recorded data for 50 or more consecutive defective restorations. The restorations that were either repaired or replaced were recalled after 12 months and characterized for developing defects. RESULTS 195 dentists recorded data on 5,889 restorations. 378 restorations required additional treatment (74 repaired, 171 replaced, 84 teeth received endodontic treatment, and 49 were extracted). Multivariable logistic regression analysis indicated that additional treatment was more likely to occur if the original restoration had been repaired (7%) compared to replaced (5%)(OR = 1.6, p < .001; 95% CI: 1.2, 2.1), if a molar tooth was restored (7%) compared to pre-molar or anterior teeth (5%, 6% respectively)(OR = 1.4, p = .010; 95% CI: 1.1, 1.7), and if the primary reason was a fracture (8%) compared to other reasons (6%)(OR = 1.3, p = .033; 95% CI: 1.1, 1.6). CONCLUSION An additional treatment was more likely to occur within the first year if the original restoration had been repaired (7%) compared to being replaced (5%). However, repaired restorations were less likely to need an aggressive treatment (replacement, endodontic treatment, or extraction) than replaced restorations. PMID:26610834

  17. Inlay-retained zirconia fixed dental prostheses: modified designs for a completely adhesive approach.

    PubMed

    Monaco, Carlo; Cardelli, Paolo; Ozcan, Mutlu

    2011-01-01

    Currently, there are many options for single-tooth replacement: metal-ceramic, all-ceramic, direct or indirect fibre-reinforced composite fixed dental prostheses (FDPs) or implants. Inlay-retained FDPs may especially be indicated when adjacent teeth have been previously restored and when implant placement is not possible or not indicated. In such cases, both metal-ceramic and fibre-reinforced composite FDPs have certain disadvantages. In this paper, we describe the use of all-ceramic inlay-retained FDPs with zirconia frameworks, veneered using a press-on technique.

  18. Lithium disilicate: the restorative material of multiple options.

    PubMed

    Culp, Lee; McLaren, Edward A

    2010-01-01

    As dentistry continues to evolve, new technologies and materials are continually being offered to the dental profession. Throughout the years restorative trends and techniques have come and gone. Some material developments have transformed the face of esthetic dentistry, while other initial concepts have already phased out and disappeared. Today, all-ceramic restorations continue to grow in the area of restorative dentistry, from pressed-ceramic techniques and materials to the growing use of zirconia, and new materials that can be created from CAD/CAM technology. This article will explore new uses for the all-ceramic material known as lithium disilicate, and the use of a digital format to design and process this material in new and exciting ways. An overview of the material as well as unique clinical procedures will be presented.

  19. Understanding dental CAD/CAM for restorations--dental milling machines from a mechanical engineering viewpoint. Part B: labside milling machines.

    PubMed

    Lebon, Nicolas; Tapie, Laurent; Duret, Francois; Attal, Jean-Pierre

    2016-01-01

    Nowadays, dental numerical controlled (NC) milling machines are available for dental laboratories (labside solution) and dental production centers. This article provides a mechanical engineering approach to NC milling machines to help dental technicians understand the involvement of technology in digital dentistry practice. The technical and economic criteria are described for four labside and two production center dental NC milling machines available on the market. The technical criteria are focused on the capacities of the embedded technologies of milling machines to mill prosthetic materials and various restoration shapes. The economic criteria are focused on investment cost and interoperability with third-party software. The clinical relevance of the technology is discussed through the accuracy and integrity of the restoration. It can be asserted that dental production center milling machines offer a wider range of materials and types of restoration shapes than labside solutions, while labside solutions offer a wider range than chairside solutions. The accuracy and integrity of restorations may be improved as a function of the embedded technologies provided. However, the more complex the technical solutions available, the more skilled the user must be. Investment cost and interoperability with third-party software increase according to the quality of the embedded technologies implemented. Each private dental practice may decide which fabrication option to use depending on the scope of the practice.

  20. Intraoral Digital Impressioning for Dental Implant Restorations Versus Traditional Implant Impression Techniques.

    PubMed

    Wilk, Brian L

    2015-01-01

    Over the course of the past two to three decades, intraoral digital impression systems have gained acceptance due to high accuracy and ease of use as they have been incorporated into the fabrication of dental implant restorations. The use of intraoral digital impressions enables the clinician to produce accurate restorations without the unpleasant aspects of traditional impression materials and techniques. This article discusses the various types of digital impression systems and their accuracy compared to traditional impression techniques. The cost, time, and patient satisfaction components of both techniques will also be reviewed.

  1. Factors affecting the placement or replacement of direct restorations in a dental school

    PubMed Central

    Silvani, Samara; Trivelato, Roberta Ferreira; Nogueira, Ruchele Dias; Gonçalves, Luciano de Souza; Geraldo-Martins, Vinícius Rangel

    2014-01-01

    Context: The knowledge of the reasons for the placement of direct restorations makes possible to trace an epidemiological profile of a specific population and to direct the teaching of dentistry to techniques that are commonly used today and will be continued performed in the future. Purpose: The aim of this study was to verify the reasons for placement and replacement of direct restorations in patients treated in the Dental Clinic of the Uberaba University – Brazil. Materials and Methods: This study evaluated 306 restorative procedures carried out on 60 patients. During the treatment planning, a form that contained information about the patient's gender, tooth number, the classification of restorations, the reasons for placement and replacement of amalgam and tooth-colored restorations, the material that had to be removed and the new material used to fill the cavities was filled for each patient. Statistical analysis was carried out using Chi-square test (α = 0.05). Results: The data showed that most of the patients were female (66.7%). Of all the restorations placed, 60.45% were 1st-time placements, while 39.55% were replacements. For 1st-time restorations, the main reason for placement was primary caries (76.76%), followed by non-carious cervical lesions (15.14%). The amalgam restorations were replaced more frequently (67.77%). The primary reason for replacements was the presence of secondary caries (for both previous amalgam (42.68%) and composite (66.67%) restorations (P < 0.05). The resin composite was the most indicated material for the new restorations (98.04%) (P < 0.05). Conclusions: The main reason for placement of direct restorations was primary caries, while secondary caries was the main reason for replacements. In almost all cases, the material used to fill the cavities was the resin composite. PMID:24808696

  2. Priorities for future innovation, research, and advocacy in dental restorative materials.

    PubMed

    Watson, T; Fox, C H; Rekow, E D

    2013-11-01

    Innovations in materials science, both within and outside of dentistry, open opportunities for the development of exciting direct restorative materials. From rich dialog among experts from dental and non-dental academic institutions and industry, as well as those from policy, research funding, and professional organizations, we learned that capitalizing on these opportunities is multifactorial and far from straightforward. Beginning from the point when a restoration is needed, what materials, delivery systems, and skills are needed to best serve the most people throughout the world's widely varied economic and infrastructure systems? New research is a critical element in progress. Effective advocacy can influence funding and drives change in practice and policy. Here we articulate both research and advocacy priorities, with the intention of focusing the energy and expertise of our best scientists on making a difference, bringing new innovations to improve oral health.

  3. Evidence summary: which dental liners under amalgam restorations are more effective in reducing postoperative sensitivity?

    PubMed

    Nasser, Mona

    2011-06-10

    Since August 2009, members of the Primary Care Dentistry Research Forum (www.dentistryresearch.org) have taken part in an online vote to identify questions in day-to-day practice that they felt most needed to be answered with conclusive research. The question that receives the most votes each month forms the subject of a critical appraisal of the relevant literature. Each month a new round of voting takes place to decide which further questions will be reviewed. Dental practitioners and dental care professionals are encouraged to take part in the voting and submit their own questions to be included in the vote by joining the website. The paper below details a summary of the findings of the ninth critical appraisal. In order to address the question raised by dentistry research forum, first a search was conducted for systematic reviews on the topic. There was one systematic review retrieved comparing bonded amalgam restorations versus non-bonded amalgam restorations. However, there was no other systematic review identified assessing the effectiveness of dental liners under amalgam restorations in general. Therefore, a search was conducted for any randomised controlled trial (RCT) comparing use of a lining under amalgam restorations versus no lining or RCTs comparing differing lining materials under amalgam against each other. There were eight relevant RCTs identified. Due to the low quality, small sample sizes or lack of adequate reporting of the outcome data, the evidence is inadequate to claim or refute a difference in postoperative sensitivity between different dental liners. Further well-conducted RCTs are needed to answer this question. These RCTs would be preferably included and synthesised in a systematic review.

  4. Measurement of Poisson's ratio of dental composite restorative materials.

    PubMed

    Chung, Sew Meng; Yap, Adrian U Jin; Koh, Wee Kiat; Tsai, Kuo Tsing; Lim, Chwee Teck

    2004-06-01

    The aim of this study was to determine the Poisson ratio of resin-based dental composites using a static tensile test method. Materials used in this investigation were from the same manufacturer (3M ESPE) and included microfill (A110), minifill (Z100 and Filtek Z250), polyacid-modified (F2000), and flowable (Filtek Flowable [FF]) composites. The Poisson ratio of the materials were determined after 1 week conditioning in water at 37 degrees C. The tensile test was performed with using a uniaxial testing system at crosshead speed of 0.5 mm/min. Data was analysed using one-way ANOVA/post-hoc Scheffe's test and Pearson's correlation test at significance level of 0.05. Mean Poisson's ratio (n=8) ranged from 0.302 to 0.393. The Poisson ratio of FF was significantly higher than all other composites evaluated, and the Poisson ratio of A110 was higher than Z100, Z250 and F2000. The Poisson ratio is higher for materials with lower filler volume fraction.

  5. Including CAD/CAM dentistry in a dental school curriculum.

    PubMed

    Browning, William D; Reifeis, Paul; Willis, Lisa; Kirkup, Michele L

    2013-01-01

    Shaping a clinical curriculum that is appropriate for novice dentists, is based on high-quality evidence of efficacy, yet reflects current practices is challenging. CAD/CAM units have been available to dentists since the late '80s. Recent improvements in the software, hardware and the clinical performance of available all-ceramic blocks have keyed a surge in interest. Based on a careful review of the systems available and, equally importantly, a review of the research regarding the longevity of reinforced glass ceramics, IUSD decided to add training on the use of the E4D CAD/CAM system to the curriculum. Students now receive lectures, preclinical hands-on training and clinical experience in fabricating all-ceramic restorations. At present any student who is interested in providing an all-ceramic restoration for his/her patient can do so using our CAD/CAM system. In a little less than one year our undergraduate dental students have provided 125 all-ceramic crowns to their patients. Clinical faculty have been impressed with the marginal fit and esthetics of the crowns. Finally, with students designing, milling, sintering and staining the restorations the CAD/CAM systems has reduced lab costs significantly.

  6. Opalescence of human teeth and dental esthetic restorative materials.

    PubMed

    Lee, Yong-Keun

    2016-12-01

    Human tooth enamel is opalescent, which renders teeth bluish in reflected and orange in transmitted color. The aim was to review opalescent property of teeth and application and mimetic reproduction in esthetic restorations. A PubMed search for articles published in English till 2015 on the opalescence of teeth and esthetic materials revealed 29 relevant papers. Opalescence was measured with OP-RT index, which was calculated as the difference in the yellow-blue and red-green color coordinates between the reflected and transmitted colors. Mean OP-RT value of human enamel was 22.9. OP-RT values of direct resin composites changed after polymerization, and the range in these materials was 5.7-23.7. OP-RT value ranges were 1.6-6.1 and 2.0-7.1 for the core and veneer ceramics, respectively. Since the OP-RT values of esthetic materials were lower than that of enamel, it is recommended that materials that can reproduce the opalescence of enamel be further designed.

  7. Seventeen Years of Using Flowable Resin Restoratives--A Dental Practitioner's Personal Clinical Review.

    PubMed

    Firla, Markus Th

    2015-04-01

    Seen through the author's eyes on the basis of his practising dentistry for almost three decades, light-activated flowable resin restoratives (FRCs) or, in common clinical dental terminology, flowable composites have gradually gained major importance in restorative dentistry. Inputs to this ongoing trend are coming from continuous improvements in material properties and the favourable handling characteristics experienced with this particular group of restoratives. Intended to be used in direct adhesive filling procedures, the number and variety of recent generations of flowable composites for lining, restoration of all cavity classes (I-V), core build-ups and, more recently, 'bulk-fill-restorations', however, necessitates a profound clinical understanding of the selective use of flowable composites to ensure clinical success and guarantee long-term high quality results. Clinical relevance: Today's flowable composites allow for reliable restoration of all kinds of defects. However, both the handling characteristics and the material properties of FRCs must be fully understood before taking advantage of their potentially excellent clinical performance.

  8. All ceramic table tops analyzed using swept source optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Stoica, Eniko Tunde; Marcauteanu, Corina; Sinescu, Cosmin; Negrutiu, Meda Lavinia; Topala, Florin; Duma, Virgil Florin; Bradu, Adrian; Podoleanu, Adrian Gh.

    2016-03-01

    Erosion is the progressive loss of tooth substance by chemical processes that do not involve bacterial action. The affected teeth can be restored by using IPS e.max Press "table tops", which replace the occlusal surfaces. In this study we applied a fast in-house Swept Source Optical Coherence Tomography (SS OCT) system to analyze IPS e.max Press "table tops". 12 maxillary first premolars have been extracted and prepared for "table tops". These restorations were subjected to 3000 alternating cycles of thermo-cycling in a range from -10°C to +50°C mechanical occlusal loads of 200 N were also applied. Using SS OCT we analyze the marginal seal of these restorations, before and after applying the mechanical and thermal strain. The characteristics of the SS OCT system utilized are presented. Its depth resolution, measured in air is 10 μm. The system is able to acquire entire volumetric reconstructions in 2.5 s. From the dataset acquired high resolution en-face projections were also produced. Thus, the interfaces between all ceramic "table tops" and natural teeth were analyzed on the cross-sections (i.e., the B-scans) produced and also on the volumetric (tri-dimensional (3D)) reconstructions, several open interfaces being detected. The study therefore demonstrates the utility of SS OCT for the analysis of lithium disilicate glass ceramic "table tops".

  9. Adhesion of Streptococcus sanguinis to dental implant and restorative materials in vitro.

    PubMed

    Hauser-Gerspach, Irmgard; Kulik, Eva M; Weiger, Roland; Decker, Eva-Maria; Von Ohle, Christiane; Meyer, Jürg

    2007-05-01

    Bacterial adhesion to tooth surfaces or dental materials starts immediately upon exposure to the oral environment. The aim of this study, therefore, was to compare the adhesion of Streptococcus sanguinis to saliva-coated human enamel and dental materials - during a one-hour period - using an in vitro flow chamber system which mimicked the oral cavity. After fluorescent staining, the number of adhered cells and their vitality were recorded. The dental materials used were: titanium (Rematitan M), gold (Neocast 3), ceramic (Vita Omega 900), and composite (Tetric Ceram). The number of adherent bacterial cells was higher on titanium, gold, and ceramic surfaces and lower on composite as compared to enamel. As for the percentage of adherent vital cells, it was higher on enamel than on the restorative materials tested. These results suggested that variations in the number and vitality of the adherent pioneer oral bacteria, S. sanguinis, in the in vitro system depended on the surface characteristics of the substratum and the acquired salivary pellicle. The in vitro adhesion model used herein provided a simple and reproducible approach to investigate the impact of surface-modified dental materials on bacterial adhesion and vitality.

  10. New Design for Rapid Prototyping of Digital Master Casts for Multiple Dental Implant Restorations

    PubMed Central

    Romero, Luis; Jiménez, Mariano; Espinosa, María del Mar; Domínguez, Manuel

    2015-01-01

    Aim This study proposes the replacement of all the physical devices used in the manufacturing of conventional prostheses through the use of digital tools, such as 3D scanners, CAD design software, 3D implants files, rapid prototyping machines or reverse engineering software, in order to develop laboratory work models from which to finish coatings for dental prostheses. Different types of dental prosthetic structures are used, which were adjusted by a non-rotatory threaded fixing system. Method From a digital process, the relative positions of dental implants, soft tissue and adjacent teeth of edentulous or partially edentulous patients has been captured, and a maser working model which accurately replicates data relating to the patients oral cavity has been through treatment of three-dimensional digital data. Results Compared with the conventional master cast, the results show a significant cost savings in attachments, as well as an increase in the quality of reproduction and accuracy of the master cast, with the consequent reduction in the number of patient consultation visits. The combination of software and hardware three-dimensional tools allows the optimization of the planning of dental implant-supported rehabilitations protocol, improving the predictability of clinical treatments and the production cost savings of master casts for restorations upon implants. PMID:26696528

  11. Anterior composite restorations in clinical practice: findings from a survey with general dental practitioners

    PubMed Central

    DEMARCO, Flávio Fernando; BALDISSERA, Rudimar Antonio; MADRUGA, Francine Cardozo; SIMÕES, Roberto Cuchiara; LUND, Rafael Guerra; CORREA, Marcos Britto; CENCI, Maximiliano Sergio

    2013-01-01

    Objectives The aim of this study was to assess technical preferences of general dental practitioners when restoring anterior composite restorations. How the level of clinical experience or post-graduate training infuenced their options was also tested. Material and Methods A cross-sectional study was performed using a questionnaire with general dental practitioners (GDPs) (n=276) in Southern Brazil. Information regarding post graduation training (specialization, master's or PhD degree) and linical experience (years since completing graduation) were gathered. The options regarding anterior composite restorations (type of composite, adhesive system, light curing unit, polishing procedures and rubber dam use) were collected. Data were submitted to descriptive analysis and associations were tested. Results Response rate was 68% (187). GDPs selected microhybrid composite (52%) and 2-step total etch adhesive system (77%). LED was the preferred method of activation for 72.8%. Immediate polishing was preferred by 75%, using a combination of techniques. Most of the respondents (74.3%) did not use rubber dam. More experienced clinicians used more halogen lights (p<0.022), performed more light monitoring (p<0.001) and were resistant to use rubber dam (p<0.012). Dentists with post-graduation training used 3-etch-and-rinse system more frequently (p<0.04), usually monitored light intensity (p<0.014) and placed rubber dam more frequently (p<0.044). Conclusions Hybrid composite, simplifed adhesives, LED units and immediate polishing were preferred by Southern Brazilian dentists for anterior composite restorations. Few dentists used rubber dam to perform composite restorations in anterior teeth. Clinical experience and post-graduation training infuenced the dentists' choices. PMID:24473714

  12. Translucency of human teeth and dental restorative materials and its clinical relevance.

    PubMed

    Lee, Yong-Keun

    2015-04-01

    The purpose was to review the translucency of human teeth and related dental materials that should be considered for the development of esthetic restorative materials. Translucency is the relative amount of light transmission or diffuse reflection from a substrate surface through a turbid medium. Translucency influences the masking ability, color blending effect, and the degree of light curing through these materials. Regarding the translucency indices, transmission coefficient, translucency parameter, and contrast ratio have been used, and correlations among these indices were confirmed. Translucency of human enamel and dentine increases in direct proportion to the wavelength of incident light in the visible light range. As for the translucency changes by aging, limited differences were reported in human dentine, while those for enamel proved to increase. There have been studies for the adjustment of translucency in dental esthetic restorative materials; the size and amount of filler and the kind of resin matrix were modified in resin composites, and the kind of ingredient and the degree of crystallization were modified in ceramics. Based on the translucency properties of human enamel and dentine, those of replacing restorative materials should be optimized for successful esthetic rehabilitation. Biomimetic simulation of the natural tooth microstructure might be a promising method.

  13. CAD/CAM systems available for the fabrication of crown and bridge restorations.

    PubMed

    Miyazaki, T; Hotta, Y

    2011-06-01

    Dental biomaterials are widely used in all areas of routine dental practice. There are mainly two methods for their application. Firstly, dental biomaterials are placed into living tissues, such as teeth, to fill the space. Secondly, dental devices such as crown and bridge restorations and dentures are fabricated using various materials to restore the morphology and function of the dentition. Crown and bridge restorations are one of the main treatment methods used by general practitioners to achieve lifelike restoration of form and function. The recent introduction of osseointegrated implants has expanded the application of crown and bridge restorations for partially edentulous patients. Mechanical durability and precision fit are mandatory requirements for crowns and bridges. The development of various casting alloys and precise casting systems has contributed to the successful use of metal-based restorations. However, patient requests for more aesthetic and biologically 'safe' materials has led to an increased demand for metal-free restorations. There is also a growing demand to provide all-ceramic restorations more routinely. New materials such as highly sintered glass, polycrystalline alumina, zirconia based materials and adhesive monomers, will assist dentists to meet this demand. In addition, new fabrication systems combined with computer-assisted fabrication systems (dental CAD/CAM) and various networks are now available. Dental technology was centred on lost-wax casting technology but we now face a revolution in crown and bridge fabrication. This article reviews the history and recent status of dental CAD/CAM, the application of CAD/CAM fabricated tooth-coloured glass ceramic crowns, and the application of all-ceramic crowns and bridges using CAD/CAM fabricated zirconia based frameworks.

  14. FATIGUE OF DENTAL CERAMICS

    PubMed Central

    Zhang, Yu; Sailer, Irena; Lawn, Brian R

    2013-01-01

    Objectives Clinical data on survival rates reveal that all-ceramic dental prostheses are susceptible to fracture from repetitive occlusal loading. The objective of this review is to examine the underlying mechanisms of fatigue in current and future dental ceramics. Data/sources The nature of various fatigue modes is elucidated using fracture test data on ceramic layer specimens from the dental and biomechanics literature. Conclusions Failure modes can change over a lifetime, depending on restoration geometry, loading conditions and material properties. Modes that operate in single-cycle loading may be dominated by alternative modes in multi-cycle loading. While post-mortem examination of failed prostheses can determine the sources of certain fractures, the evolution of these fractures en route to failure remains poorly understood. Whereas it is commonly held that loss of load-bearing capacity of dental ceramics in repetitive loading is attributable to chemically-assisted 'slow crack growth' in the presence of water, we demonstrate the existence of more deleterious fatigue mechanisms, mechanical rather than chemical in nature. Neglecting to account for mechanical fatigue can lead to gross overestimates in predicted survival rates. Clinical significance Strategies for prolonging the clinical lifetimes of ceramic restorations are proposed based on a crack-containment philosophy. PMID:24135295

  15. All-ceramic inlay-retained fixed partial bridge using a CAD-CAM produced Y-TZP framework and fluoroapatite veneering ceramic: a clinical report.

    PubMed

    Hirata, Ronaldo; Viotti, Ronaldo; Reis, Andre Figueiredo; de Andrade, Oswaldo Scopin

    2007-11-01

    All-ceramic materials have become an excellent option for both anterior and posterior fixed partial dentures (FPDs) due to advances in esthetic and mechanical properties. This clinical report describes the use of an all-ceramic inlay-retained three-unit FPD for replacement of a maxillary second premolar. Prosthetic restorative materials consisted of a CAD-CAM processed presintered yttrium stabilized zirconium oxide (Y-TZP) framework and a fluoroapatite veneering ceramic. The minimally invasive preparation technique and advantages of this highly esthetic and resistant treatment option are discussed.

  16. The decision to repair or replace a defective restoration is affected by who placed the original restoration: findings from the National Dental PBRN

    PubMed Central

    Gordan, Valeria V; Riley, Joseph; Geraldeli, Saulo; Williams, O. Dale; Spoto, Joseph C; Gilbert, Gregg H

    2014-01-01

    Objectives To evaluate how restoration characteristics are associated with the decision to repair or replace an existing restoration. The following hypotheses were studied: Dentists who placed the original restoration are more likely to repair instead of replace restorations (H1) that are in molar teeth; (H2) that are in the upper arch; (H3) that have amalgam restorative material; (H4) if a fracture is not the primary reason for the defect; and (H5) when the restoration comprises more than one surface. Methods This cross-sectional study used a consecutive patient/restoration recruitment design. 194 dentists members of a dental practice-based research network recorded data on restorations in permanent teeth that needed repair or replacement. Results For 6,623 of the 8,770 defective restorations in 6,643 patients, the treatment was provided by the dentist who had not placed the original restoration (75%). The 2-way interaction revealed that dentists who had placed the original restoration often chose to repair when the defective restoration was in a molar, relative to premolar or anterior teeth (OR = 2.2, p < .001); and chose to replace when the restoration had amalgam (OR = 0.5, p < .001), and when it was a fracture compared to another reason (OR = 0.8, p = 001). Conclusion Most dentists are not conservative when they revisit a restoration that they originally placed regardless of type of failure, number of surfaces or material used. However, dentists who had placed the original restoration were significantly more likely to repair it when the defective restoration was in a molar tooth. PMID:25223822

  17. ALL-CERAMIC AND PORCELAIN-FUSED-TO-METAL FIXED PARTIAL DENTURES: A COMPARATIVE STUDY BY 2D FINITE ELEMENT ANALYSES

    PubMed Central

    Motta, Andréia Barreira; Pereira, Luiz Carlos; da Cunha, Andréia R.C.C

    2007-01-01

    All-ceramic fixed partial dentures (FPDs) have an esthetic approach for oral rehabilitation. However, metal-ceramic FPDs are best indicated in the posterior area where the follow-up studies found a lower failure rate. This 2D finite element study compared the stress distribution on 3-unit all-ceramic and metal-ceramic FPDs and identified the areas of major risk of failure. Three FPD models were designed: (1) metal-ceramic FPD; (2) All-ceramic FPD with the veneering porcelain on the occlusal and cervical surface of the abutment tooth; (3) All-ceramic FPD with the veneering porcelain only on the occlusal surface. A 100 N load was applied in an area of 0.5 mm2 on the working cusps, following these simulations: (1) on the abutment teeth and the pontic; (2) only on the abutment teeth; and (3) only on the pontic. Relative to the maximum stress values found for the physiological load, all-ceramic FPD with only occlusal veneering porcelain produced the lowest stress value (220 MPa), followed by all-ceramic FPD with cervical veneering porcelain (322 MPa) and metal-ceramic FPD (387 MPa). The stress distribution of the load applied on the abutments was significantly better compared to the other two load simulations. The highest principal stress values were low and limited in a small area for the three types of models under this load. When the load was applied on the pontic, the highest stress values appeared on the connector areas between the abutments and pontic. In conclusion, the best stress values and distribution were found for the all-ceramic FPD with the veneering porcelain only on the occlusal surface. However, in under clinical conditions, fatigue conditions and restoration defects must be considered. PMID:19089168

  18. Restorative treatment and use of local anesthesia in free and subsidized public dental services in Helsinki, Finland.

    PubMed

    Palotie, Ulla; Vehkalahti, Miira

    2003-08-01

    Our aim was to evaluate restorative treatment and the use of local anesthetics in free and subsidized public dental care in Helsinki, Finland. Public dental clinics are open to all patients under the age of 36, and to some specific groups above that age. Patients up to age 19 receive all treatment free of charge and others at highly subsidized rates. Data were collected in May 2001 during a maximum 2-week period covering all public dental clinics in Helsinki. A one-page questionnaire was sent to all dentists (n = 140) in clinical fields. The data requested included the patient's gender and year of birth, and details on restorations: which tooth and which surfaces were filled, the reason for placement or replacement, the material used, and use of local anesthetic. The response rate was 96%. Of all restorations (n = 3057) placed, 14% were in primary teeth and in permanent teeth: 17% in premolars, 17% in incisors, and 52% in molars; the restorative material most often used was composite resin (69%). Glass-ionomer/compomers dominated in the primary teeth. Local anesthetic was used least (35%) in patients under 13 years of age. Replacements of restorations accounted for 10% of all in the free service (under 20 years of age) and 46% in subsidized dental care (20 and older). The major reasons for replacement were secondary caries (41%) and fractured or lost restoration (40%).

  19. Effect of the shades of background substructures on the overall color of zirconia-based all-ceramic crowns

    PubMed Central

    Tulapornchai, Chantana; Mamani, Jatuphol; Kamchatphai, Wannaporn; Thongpun, Noparat

    2013-01-01

    PURPOSE The objective of this study was to determine the effect of the color of a background substructure on the overall color of a zirconia-based all-ceramic crown. MATERIALS AND METHODS Twenty one posterior zirconia crowns were made for twenty subjects. Seven premolar crowns and six molar crowns were cemented onto abutments with metal post and core in the first and second group. In the third group, eight molar crowns were cemented onto abutments with a prefabricated post and composite core build-up. The color measurements of all-ceramic crowns were made before try-in, before and after cementation. A repeated measure ANOVA was used for a statistical analysis of a color change of all-ceramic crowns at α=.05. Twenty four zirconia specimens, with different core thicknesses (0.4-1 mm) were also prepared to obtain the contrast ratio of zirconia materials after veneering. RESULTS L*, a*, and b* values of all-ceramic crowns cemented either on a metal cast post and core or on a prefabricated post did not show significant changes (P>.05). However, the slight color changes of zirconia crowns were detected and represented by ΔE*ab values, ranging from 1.2 to 3.1. The contrast ratios of zirconia specimens were 0.92-0.95 after veneering. CONCLUSION No significant differences were observed between the L*, a*, and b* values of zirconia crowns cemented either on a metal cast post and core or a prefabricated post and composite core. However, the color of a background substructure could affect the overall color of posterior zirconia restorations with clinically recommended core thickness according to ΔE*ab values. PMID:24049574

  20. Computer-Assisted System to Automate Production of Posterior Dental Restorations

    NASA Astrophysics Data System (ADS)

    Rekow, E. Dianne; Erdman, Arthur G.; Speidel, T. Michael

    1986-07-01

    The feasibility of a system which is capable of automating production of posterior dental restorations has been investigated. Data acquisition can be accomplished in a clinical setting using standard equipment to obtain stereoscopic views of the prepared tooth, adjacent and opposing teeth, and the jaw in motion. Data from the patient is digitized with a very high resolution digitizer. Stereophotogrammetric reconstruction and kinematic analysis establish the three-dimensional envelope in which the restoration must function. Ideal tooth profiles have been digitized for each of the fourteen unique teeth. Each tooth profile is represented by B-spline or Bezier curves and surfaces. Utilizing local influence properties of these curves and surfaces, the ideal profile can be modified to provide proper function and fill the available space, yielding a morphologically correct restor-ation which meets the unique design requirements for a specific patient. Spline curves and surfaces also ensure that the surfaces are well behaved, without discontinuities. This property facilitates generation of tool paths for numerically controlled machining. The latest version of Control Data Corporation's ICEM-DDN package, with its interface with the newly developed graphics programming language (GPL) is used to create those tool paths. Special consideration is given to unique requirements of mating internal and external sur-faces as well as to high precision, small size manufacturing.

  1. Cementation of prosthetic restorations: from conventional cementation to dental bonding concept.

    PubMed

    Haddad, Marcela Filié; Rocha, Eduardo Passos; Assunção, Wirley Gonçalves

    2011-05-01

    The cementation procedure of metal-free fixed partial dentures exhibits special characteristics about the porcelains and cementation agents, which turns the correct association between these materials necessary. Our purpose in this literature review was to point the main groups of cements associated to metal-free restoration and discuss about the advantages, disadvantages, and recommendations of each one. Our search was confined to the electronic databases PubMed and SciELO and to books about this matter. There are essentially 3 types of hard cement: conventional, resin, or a hybrid of the two. The metal-free restorations can be fixed with conventional or resin cements. The right choice of luting material is of vital importance to the longevity of dental restorative materials. Conventional cements are advantageous when good compressive straight, good film thickness, and water dissolution resistance are necessary. However, they need an ideal preparation, and they are not acid dissolution resistant. Conventional cements are indicated to porcelains that cannot be acid etched. Resin cements represent the choice to metal-free restoration cementation because they present better physical properties and aesthetic than conventional agents.

  2. An interdisciplinary noninvasive all-ceramic treatment concept for nonsyndromic oligodontia in adolescence.

    PubMed

    Selz, Christian F; Jung, Britta A; Guess, Petra C

    2015-02-01

    Oligodontia has a substantial oral functional and psychosocial impact on the quality of life of children. The treatment of oligodontia in adolescence is an interdisciplinary approach which can include extraction of the primary teeth with orthodontic space closure, or prosthodontic rehabilitation. This case report describes a conservative approach for the rehabilitation of a 12-year-old patient with 19 ageneses (excluding third molars) of permanent teeth, infraocclusion of the persisting primary teeth, deep overbite, and reduced mesiodistal dimension of the maxillary incisors with a central diastema. The treatment plan to restore esthetics and function included an initial noninvasive prosthetic rehabilitation for deep bite correction with additive leucite-reinforced glass-ceramic onlays/veneers until definitive orthodontic and implant therapy are reevaluated and determined in adulthood. Esthetics, functional occlusion, and crown-to-root ratio remained stable over a follow-up period of 3 years. No signs of fractures within the all-ceramic restorations or symptoms of a temporomandibular disorder were evident.

  3. Fabrication of Zirconia-Reinforced Lithium Silicate Ceramic Restorations Using a Complete Digital Workflow

    PubMed Central

    Rinke, Sven; Rödiger, Matthias; Ziebolz, Dirk; Schmidt, Anne-Kathrin

    2015-01-01

    This case report describes the fabrication of monolithic all-ceramic restorations using zirconia-reinforced lithium silicate (ZLS) ceramics. The use of powder-free intraoral scanner, generative fabrication technology of the working model, and CAD/CAM of the restorations in the dental laboratory allows a completely digitized workflow. The newly introduced ZLS ceramics offer a unique combination of fracture strength (>420 MPa), excellent optical properties, and optimum polishing characteristics, thus making them an interesting material option for monolithic restorations in the digital workflow. PMID:26509088

  4. Methicillin-resistant Staphylococcus aureus and infection control for restorative dental treatment in nursing homes.

    PubMed

    Hall, David L

    2003-01-01

    The prevalence of methicillin-resistant Staphylococcus aureus (MRSA) in nursing home residents now averages 20-35%. This includes both numerous asymptomatic mostly unidentified carriers, and the occasional patient with an active infection. Among the most common sites for positive MRSA colonization are the nares and mouth (saliva). Ohio State University (OSU) dental students perform routine restorative dental care onsite in local nursing homes using portable equipment including handpieces that can generate aerosols. Using a series of cultured test swabs and plates, this pilot study suggests that protection for both dental health care personnel and patients are provided by the following: 1. universal barrier precautions (for example, gloves, gowns, masks, hats, facial shields, glasses), 2. surface disinfectants, 3. pre-op 0.12% chlorhexidene mouth rinses, 4. high volume evacuation, 5. perioral skin scrubs. Additional infection control methods, techniques and equipment were evaluated and compared including rubber dam isolation, hand excavation and bond technique, high-speed air turbine and electric "high" speed handpiece. There was no indication of a special tendency or heightened ability of MRSA to aerosolize.

  5. Materials design in the performance of all-ceramic crowns.

    PubMed

    Lawn, Brian R; Pajares, Antonia; Zhang, Yu; Deng, Yan; Polack, Mariano A; Lloyd, Isabel K; Rekow, E Dianne; Thompson, Van P

    2004-06-01

    Results from a systematic study of damage in material structures representing the basic elements of dental crowns are reported. Tests are made on model flat-layer specimens fabricated from various dental ceramic combinations bonded to dentin-like polymer substrates, in bilayer (ceramic/polymer) and trilayer (ceramic/ceramic/polymer) configurations. The specimens are loaded at their top surfaces with spherical indenters, in simulation of occlusal function. The onset of fracture is observed in situ using a video camera system mounted beneath the transparent polymer substrate. Critical loads to induce fracture and deformation at the ceramic top and bottom surfaces are measured as functions of layer thickness and contact duration. Radial cracking at the ceramic undersurface occurs at relatively low loads, especially in thinner layers. Fracture mechanics relations are used to confirm the experimental data trends, and to provide explicit dependencies of critical loads in terms of key variables: material-elastic modulus, hardness, strength and toughness; geometric-layer thicknesses and contact radius. Tougher, harder and (especially) stronger materials show superior damage resistance. Critical loads depend strongly (quadratically) on crown net thickness. The analytic relations provide a sound basis for the materials design of next-generation dental crowns.

  6. Accuracy of intraoral and extraoral digital data acquisition for dental restorations

    PubMed Central

    Rudolph, Heike; Salmen, Harald; Moldan, Matthias; Kuhn, Katharina; Sichwardt, Viktor; Wöstmann, Bernd; Luthardt, Ralph Gunnar

    2016-01-01

    ABSTRACT The computer-aided design (CAD) and computer-aided manufacturing (CAM) process chain for dental restorations starts with taking an impression of the clinical situation. For this purpose, either extraoral digitization of gypsum models or intraoral digitization can be used. Despite the increasing use of dental digitizing systems, there are only few studies on their accuracy. Objective This study compared the accuracy of various intraoral and extraoral digitizing systems for dental CAD/CAM technology. Material and Methods An experimental setup for three-dimensional analysis based on 2 prepared ceramic master dies and their corresponding virtual CAD-models was used to assess the accuracy of 10 extraoral and 4 intraoral optical non-contact dental digitizing systems. Depending on the clinical procedure, 10 optical measurements of either 10 duplicate gypsum dies (extraoral digitizing) or directly of the ceramic master dies (intraoral digitizing) were made and compared with the corresponding CAD-models. Results The digitizing systems showed differences in accuracy. However, all topical systems were well within the benchmark of ±20 µm. These results apply to single tooth measurements. Conclusions Study results are limited, since only single teeth were used for comparison. The different preparations represent various angles and steep and parallel opposing tooth surfaces (incisors). For most digitizing systems, the latter are generally the most difficult to capture. Using CAD/CAM technologies, the preparation angles should not be too steep to reduce digitizing errors. Older systems might be limited to a certain height or taper of the prepared tooth, whereas newer systems (extraoral as well as intraoral digitization) do not have these limitations. PMID:27008261

  7. Prosthetic outcome of cement-retained implant-supported fixed dental restorations: a systematic review.

    PubMed

    Chaar, M S; Att, W; Strub, J R

    2011-09-01

    The aim of the article is to assess the current literature in terms of the prosthetic outcome of cement-retained implant-supported fixed restorations, as well as to determine the type of cement that can be recommended for clinical application. A review of the literature published up to May 2010 was conducted to identify clinical studies about cement-retained implant-supported fixed restorations. The search strategy applied was a combination of MeSH terms and free text words, including the following keywords: implants, implant-supported fixed dental prostheses (FDPs), bridges, implant-supported single crowns (SCs), cement-retained, cement fixation, cement, cementation, cement failure, retention, and loss of retention, technical complications, mechanical complications, prosthetic complication, retrievability and maintenance. Thirty-two studies met the inclusion criteria. The studies were divided into two categories: 15 short-term clinical studies with an observation period of less than 5 years, and 17 long-term clinical studies with an observation period of 5 years and more. The most common technical complications of cement-retained implant-supported fixed restorations were loss of retention, chipping and abutment screw loosening. The results of the current review revealed no guidelines about cement or cementation procedures. It may be stated that despite the questionable retrievability of cement-retained implant-supported fixed restorations, this treatment modality is a reliable and effective option, especially for implant-supported SCs and short-span FDPs. The literature does not provide accurate information about the clinical outcome of cement-retained implant-supported fixed restorations nor about the ideal type of cement that facilitates stability and maintains retrievability. Standardised randomised clinical trials will provide valuable information to this issue.

  8. Matching the optical properties of direct esthetic dental restorative materials to those of human enamel and dentin

    NASA Astrophysics Data System (ADS)

    Ragain, James Carlton, Jr.

    One of the goals of the restorative dentist is to restore the appearance of the natural dentition. Clinical matching of teeth and restorative materials are seldom accurate and shade selection techniques are subjective. The first specific aim of this research was to characterize the optical absorption and scattering that occurs within enamel, dentin, and composite resin and compomer restorative materials and to relate those phenomena to translucency and color. The second aim was to evaluate small color differences among composite restorative materials which would be detectable by humans. The last aim was to lay the foundation for developing an improved model of specifying layers of dental restorative materials in order to match the translucency and color to those of human enamel. The Kubelka-Munk theory was validated for enamel, dentin, and the restorative materials. These tissues and materials were then characterized in terms of their color parameters. Tooth cores were also characterized in terms of color space parameters. Human subjects were evaluated for their abilities to discriminate small color differences in the dental composite resin materials. The following conclusions were derived from this study: (1) Kubelka-Munk theory accurately predicts the diffuse reflectance spectra of enamel, dentin, and the direct esthetic dental restorative materials studied. (2) Scattering and absorption coefficients of the dental tissues and esthetic restorative materials can be directly calculated from diffuse reflectance measurements of a uniformly thick slab of tissue/material using black and white backings and the appropriate refractive index. (3) For tooth cores, there is a positive correlation between L* and b* and a negative correlation between L* and a*. (4) The range of translucency parameters for the restorative materials studied does not match those of enamel and dentin. (5) None of the shades of the dental composite resin restorative materials studied fit into the

  9. [The impact of ultrasonic dental hygiene procedures on the bonding strength of restorations].

    PubMed

    Kuznetsov, D L; Mel'nik, A A; Laze, R; Petrikas, O A; Petrikas, I V

    2013-01-01

    Ultrasonic calculus scaling has become a common oral hygiene procedure in patients with composite restorations, dental veneers, orthodontic brackets. The aim of the study was to evaluate in vitro the influence of the EMS-ultrasonic system scaling on the flowable composite bond strength to the tooth enamel, dentine, and e-max ceramic. The samples were divided into three groups: 1 group (composite bonded to enamel), 2 group (composite bonded to dentine), 3 group (composite bonded to e-max ceramic). The bonded samples were loaded to failure in the universal testing machine. The shear bond strength was calculated in newtons (N). T (Student's)-test was used to evaluate the data. Significantly lower bond strengths were observed with the ultrasonic treated samples in each groups. The EMS-ultrasonic system scaling significantly decreases the flowable composite bond strength to the tooth enamel, dentine, and e-max ceramic.

  10. Properties of methacrylate-thiol-ene formulations as dental restorative materials

    PubMed Central

    Cramer, Neil B.; Couch, Charles L.; Schreck, Kathleen M.; Boulden, Jordan E.; Wydra, Robert; Stansbury, Jeffrey W.; Bowman, Christopher N.

    2010-01-01

    Objectives The objective of this study was to evaluate ternary methacrylate-thiol-ene systems, with varying thiol-ene content and thiol:ene stoichiometry, as dental restorative resin materials. It was hypothesized that an off-stoichiometric thiol-ene component would enhance interactions between the methacrylate and thiol-ene processes to reduce shrinkage stress while maintaining equivalent mechanical properties. Methods Polymerization kinetics and functional group conversions were determined by Fourier transform infrared spectroscopy (FTIR). Cured resin mechanical properties were evaluated using a three-point flexural test, carried out with a hydraulic universal test system. Polymerization shrinkage stress was measured with a tensometer coupled with simultaneous real-time conversion monitoring. Results The incorporation of thiol-ene mixtures as reactive diluents into conventional dimethacrylate resins previously was shown to combine synergistically advantageous methacrylate mechanical properties with the improved polymerization kinetics and reduced shrinkage stress of thiol-ene systems. In these systems, due to thiol consumption resultant from both the thiol-ene reaction and chain transfer involving the methacrylate polymerization, the optimum thiol:ene stoichiometry deviates from the traditional 1:1 ratio. Increasing the thiol:ene stoichiometry up to 3:1 results in systems with equivalent flexural modulus, 6 – 20 % reduced flexural strength, and 5 – 33 % reduced shrinkage stress relative to 1:1 stoichiometric thiol:ene systems. Significance Due to their improved overall functional group conversion, and shrinkage stress reduction while maintaining equivalent flexural modulus, methacrylate-thiol-ene resins, particularly those with excess thiol, beyond the conventional 1:1 thiol:ene molar ratio, yield superior dental restorative materials compared with purely dimethacrylate resins. PMID:20553973

  11. Effectiveness of benzocaine in reducing deep cavity restoration and post-extraction stress in dental patients

    PubMed Central

    Al-Samadani, Khalid H.; Gazal, Giath

    2015-01-01

    Objectives: To investigate the effectiveness of topical anesthetic, 20% benzocaine in relieving pain and stress in patients following deep cavity restoration and extraction of teeth under local anesthesia (LA). Methods: A prospective clinical trial was conducted from October 2014 until April 2015 at Taibah University, Al Madinah Al Munawarah, Kingdom of Saudi Arabia. Forty-five patients were included in the 20% benzocaine group, and 46 in the normal saline group. Evaluation of the dental stress was made pre-operatively and immediately post-operative treatment using the visual analogue scale (VAS). Furthermore, discomfort of the injections were recorded by the patients after each treatment on standard 100 mm VAS, tagged at the endpoints with “no pain” (0 mm) and “unbearable pain” (100 mm). Results: There were statistically significant differences between the mean stress scores for patients in the benzocaine and normal saline groups post-operatively (p=0.002). There were significant differences between the mean pain scores for patients in the post buccal injection (p=0.001), post palatal injection (p=0.01), and the post inferior alveolar nerve block groups (p=0.02). Buccal, palatal, and inferior alveolar nerve block injections were more painful for patients in the normal saline group than the benzocaine group. Conclusion: This investigation has demonstrated that post-operative stress associated with deep cavity restoration and dental extractions under LA can be reduced by the application of topical anesthetic (20% benzocaine) at the operative site for intra-oral injections. PMID:26593169

  12. Ultrashort pulse laser processing of hard tissue, dental restoration materials, and biocompatibles

    NASA Astrophysics Data System (ADS)

    Yousif, A.; Strassl, M.; Beer, F.; Verhagen, L.; Wittschier, M.; Wintner, E.

    2007-07-01

    During the last few years, ultra-short laser pulses have proven their potential for application in medical tissue treatment in many ways. In hard tissue ablation, their aptitude for material ablation with negligible collateral damage provides many advantages. Especially teeth representing an anatomically and physiologically very special region with less blood circulation and lower healing rates than other tissues require most careful treatment. Hence, overheating of the pulp and induction of microcracks are some of the most problematic issues in dental preparation. Up till now it was shown by many authors that the application of picosecond or femtosecond pulses allows to perform ablation with very low damaging potential also fitting to the physiological requirements indicated. Beside the short interaction time with the irradiated matter, scanning of the ultra-short pulse trains turned out to be crucial for ablating cavities of the required quality. One main reason for this can be seen in the fact that during scanning the time period between two subsequent pulses incident on the same spot is so much extended that no heat accumulation effects occur and each pulse can be treated as a first one with respect to its local impact. Extension of this advantageous technique to biocompatible materials, i.e. in this case dental restoration materials and titanium plasma-sprayed implants, is just a matter of consequence. Recently published results on composites fit well with earlier data on dental hard tissue. In case of plaque which has to be removed from implants, it turns out that removal of at least the calcified version is harder than tissue removal. Therefore, besides ultra-short lasers, also Diode and Neodymium lasers, in cw and pulsed modes, have been studied with respect to plaque removal and sterilization. The temperature increase during laser exposure has been experimentally evaluated in parallel.

  13. The role of the ionomer glass component in polyacid-modified composite resin dental restorative materials.

    PubMed

    Adusei, Gabriel O; Deb, Sanjukta; Nicholson, John W

    2004-07-01

    In order to model the processes that occur within polyacid-modified composite resin ("compomer") dental restoratives, a series of experiments has been carried out with silanated and silane-free ionomer glass G338, and silanated and silane-free unreactive glass (Raysorb T-4000). In an acid-base reaction with dental grade aqueous maleic acid-acrylic acid copolymer solution, the setting time of the silanted G338 was found to be 9 min, compared with 5 min for the silane-free glass. Inclusion of each glass in an experimental composite resin system showed that the formulations which contained G338 absorbed more water than the formulations which contained Raysorb T-4000, regardless of whether or not the glass was silanted. Biaxial flexure strength was superior for experimental composites containing Raysorb T-4000, with highest results being obtained with the silanated glass. Overall these results demonstrate that silanation of the filler is essential for optimal physical properties but that, for the ionomer glass, it inhibits the acid-base reaction. The presence of ionomer glass led to an increase in water uptake compared with the unreactive glass, regardless of the presence of silane.

  14. Thermal stability of direct dental esthetic restorative materials at elevated temperatures.

    PubMed

    Robinson, F G; Rueggeberg, F A; Lockwood, P E

    1998-11-01

    With increasing use of direct esthetic restorative materials, the identity of a body may rely upon knowledge of temperature effects on this class of dental restorations. This research examined the effect of atmospheric gas on thermal decomposition and color change of a wide variety of direct esthetic restorative materials. Cured discs (4 x 1 and 8 x 1 mm) were made using manufacturer's directions: traditional glass ionomer (Fuji II), light-curable resonomer (Fuji II LC), compomer (Geristore), and three types of resin composites--highly filled, urethane-based (Occlusin), and two Bis-GMA/TEGDMA resins: hybrid (Herculite XRV) and microfill (Silux Plus). Three replications of each material were heated at 5 degrees C/min in a thermogravimetric analysis unit using either room air or nitrogen purge to simulate different thermal environments. First derivative values of percent weight loss with respect to temperature were obtained to determine temperatures associated with increased decomposition rates. Room-air heating showed greater numbers of decomposition events than did nitrogen-heated discs. The only material decomposing less than 200 degrees C in either atmosphere was traditional glass ionomer. The majority of decomposition occurred between 200 degrees and 500 degrees C for all materials. Only products containing glass ionomer components decomposed between 600 degrees and 800 degrees C. Room-air heating resulted in ash white discs at 800 degrees C and higher. Specimens heated in nitrogen were gray to black at 600 degrees C and higher. Heating atmosphere greatly affected color, and some products demonstrated distinguishing color changes: glass ionomers, in particular, showed characteristic color features. An atlas was constructed from color change of specimens recovered after 200 degrees, 400 degrees, 600 degrees, 800 degrees, and 1000 degrees C compared with non-heated controls.

  15. A new technique for screening chemical toxicity to the pulp from dental restorative materials and procedures.

    PubMed

    Hume, W R

    1985-11-01

    An in vitro test system is described which allows for quick and relatively inexpensive examination of the potential for chemical toxicity to the pulp of materials and procedures used in the restoration of single teeth. The test system consisted of two sequential steps. First, a restorative procedure was carried out on a freshly-extracted human tooth crown, to the pulpal surface of which had been attached a chamber filled with sterile tissue-culture medium. The preparation was kept at 37 degrees C. The culture medium was removed at day one and replaced with fresh medium, which was removed at day 3. In the second step, we used a standard tissue-culture toxicity assessment technique to examine both culture medium samples for the presence of chemical toxins. In use, this system gave results which correlated well with the known clinical potential for pulpal toxicity of various dental materials and techniques. For example, zinc oxide-eugenol used as temporary filling or base had no apparent potential for toxicity. Sealing a cotton pellet containing phenol into a cavity was of high apparent potential toxicity. Acrylic resin as intracoronal or extracoronal fillings showed potential for toxicity; this potential was decreased by lining with calcium hydroxide cement. Composite resin placed onto etched dentin had apparent toxic potential, but had less such potential when placed onto unetched dentin. The technique had some advantages over previously described in vitro toxicity test for restorative materials, because it included a step requiring diffusion of potential toxins into and through human dentin, and because it allowed for examination of variations in technique which mimic clinical behavior, and of materials used in sequence or in combination.

  16. Rehabilitation of a patient with amelogenesis imperfecta using porcelain veneers and CAD/CAM polymer restorations: A clinical report.

    PubMed

    Saeidi Pour, Reza; Edelhoff, Daniel; Prandtner, Otto; Liebermann, Anja

    2015-01-01

    The complete dental rehabilitation of patients with a vertical dimension loss (VDL) caused by structural enamel deficits associated with amelogenesis imperfecta (AI) represents a difficult challenge for restorative teams. Accurate analysis and treatment planning that includes esthetic and functional evaluations and adequate material selection are important prerequisites for successful results. Long-term provisional restorations play an important role in exploring and elucidating the patients' esthetic demands and functional needs. Restorative treatment options can vary from requiring only oral hygiene instructions to extensive dental restorations that include composite fillings, ceramic veneers, metal-ceramic, or all-ceramic crowns. This case report describes a full-mouth rehabilitation of a patient with amelogenesis imperfecta including the case planning, bite replacement, preparation, and restoration setting steps with an experimental CAD/CAM polymer and porcelain veneers.

  17. A comparative evaluation of microleakage of restorations using silorane-based dental composite and methacrylate-based dental composites in Class II cavities: An in vitro study

    PubMed Central

    Sivakumar, Jambai Sampath Kumar; Prasad, A. S.; Soundappan, Saravanapriyan; Ragavendran, N.; Ajay, R.; Santham, Krishnamoorthy

    2016-01-01

    Aim: The aim of this in vitro study was to evaluate and compare the microleakage of restorations using low shrinkage silorane-based dental composite and methacrylate-based dental composites in Class II cavity at the occlusal and gingival margins. Materials and Methods: Sixty mandibular molars were collected and divided into three experimental groups and one negative control group. Class II slot cavity was prepared on the mesial surface. Experimental groups were restored with Group I: silorane-based microhybrid composite, Group II: methacrylate-based nanohybrid composite, and Group III: Methacrylate-based microhybrid composite, respectively. Group IV: negative control. The samples were thermocycled, root apices were sealed with sticky wax and coated with nail varnish except 1 mm around the restoration. This was followed by immersion in 2% Rhodamine-B dye solution under vacuum at room temperature for 24 h. Then, the samples were sectioned longitudinally in the mesiodistal direction and evaluated under stereomicroscope ×40 magnification. Scoring was done according to the depth of dye penetration in to the cavity. Statistical analysis of the data was done. Results: The results were that no statistically significant difference in the microleakage at the occlusal margin for all the restorative materials, whereas at the gingival margin, silorane-based microhybrid composite showed less microleakage than the methacrylate-based nano- and micro-hybrid composites. Conclusion: In general, silorane-based microhybrid composite had less microleakage among the other materials used in this in vitro study. PMID:27829753

  18. All-ceramic prosthetic rehabilitation of a worn dentition: Use of a distal cantilever. Two-year follow-up

    PubMed Central

    Chekhani, Usama N.; Mikeli, Aikaterini A.; Huettig, Fabian K.P.

    2013-01-01

    The rehabilitation of heavily abraded occlusion in patients with parafunctional habits is a restorative challenge to the dentist. Use of all-ceramic systems in such cases is widely considered, but uncertainty over their resistance hinders their broad use. The authors would like to illustrate a possible approach by mixing two all-ceramic systems based on zirconium dioxide and lithium disilicate. A 48-year-old female patient attended with reduced vertical dimension in a full dentition. She suffered from craniomandibular (CMD) pain and desired an esthetic rehabilitation. Prosthodontic treatment was started in a pain-free condition, after correction of the vertical dimension with an occlusal splint, over four months. Determination of the treatment was based on the clinical findings: IPS e.max® ZirCAD frameworks veneered with IPS e.max® Ceram were used for discolored retainers or subgingival finishing lines. All the rest received IPS e.max® Press crowns. A zirconia-based, single-tooth-retained distal cantilever reconstruction was used to replace a missing second molar. No technical or biological complication was observed 24 months after treatment. The patient was highly satisfied and pain-free. PMID:23878577

  19. The Comparative Evaluation of the Translucency of Crowns Fabricated with Three Different All-Ceramic Materials: An in Vitro Study

    PubMed Central

    Ramani, Y.V.; Rathod, Asha M.; Ram, Sabita M.; Turakhia, Hetal

    2015-01-01

    Introduction: All-ceramic crowns with different core materials of different strength and aesthetics are available in recent years. The aesthetics of the crown depends mainly on the shade and translucency. Clinician should be aware of the quality and characteristics of these materials so that they will be able to opt for good material for successful clinical use. Aim and Objective: The aim of this study was to evaluate and compare the translucency of crowns fabricated with three different commercially available all-ceramic materials viz. Alumina - CAD-CAM Procera, Lithium disilicate - Pressable IPS e.max Press, Zirconia - CAD-CAM Lava. Materials and Methods: All-ceramic crowns (5 per each group and total of 15 samples) were made of Alumina – CAD-CAM Procera (Group I), Lithium disilicate – Pressable IPS e.max Press (Group II), Zirconia – CAD-CAM Lava (Group III) and veneered with their respective layering ceramic. Evaluation for the Translucency (CR=Yb/Yw) over the White (Yw) and Black (Yb) backgrounds at the Incisal, Middle, Cervical, Mesial and Distal thirds of each crown were done using the Spectrophotometer. The results obtained were statistically analyzed by Paired t-test (p<0.05) and Analysis of Variance (p<0.05) for the test of significance among the groups. Results: Significant differences in the contrast ratios were obtained among the three Groups (p<0.001). In this study, Group II Lithium disilicate–Pressable IPS e.max Press showed higher translucency (0.54). Group III Zirconia – CAD-CAM Lava showed the least translucency (0.75) and the translucency of Group I Alumina – CAD-CAM Procera (0.7) was in between both the groups. Conclusion: Translucency of material gives fair idea to clinician for the choice of material in different zones during replacement and suitability for restoration in aesthetic zone. Selection of all ceramic system depends on the translucency needed for successful prosthesis of artificial tooth so that it mimics patient

  20. Microleakage of Four Dental Cements in Metal Ceramic Restorations With Open Margins

    PubMed Central

    Eftekhar Ashtiani, Reza; Farzaneh, Babak; Azarsina, Mohadese; Aghdashi, Farzad; Dehghani, Nima; Afshari, Aisooda; Mahshid, Minu

    2015-01-01

    Background: Fixed prosthodontics is a routine dental treatment and microleakage is a major cause of its failure. Objectives: The aim of this study was to assess the marginal microleakage of four cements in metal ceramic restorations with adapted and open margins. Materials and Methods: Sixty sound human premolars were selected for this experimental study performed in Tehran, Iran and prepared for full-crown restorations. Wax patterns were formed leaving a 300 µm gap on one of the proximal margins. The crowns were cast and the samples were randomly divided into four groups based on the cement used. Copings were cemented using zinc phosphate cement (Fleck), Fuji Plus resin-modified glass ionomer, Panavia F2.0 resin cement, or G-Cem resin cement, according to the manufacturers’ instructions. Samples were immersed in 2% methylene blue solution. After 24 hours, dye penetration was assessed under a stereomicroscope and analyzed using the respective software. Data were analyzed using ANOVA, paired t-tests, and Kruskal-Wallis, Wilcoxon, and Mann-Whitney tests. Results: The least microleakage occurred in the Panavia F2.0 group (closed margin, 0.18 mm; open margin, 0.64 mm) and the maximum was observed in the Fleck group (closed margin, 1.92 mm; open margin, 3.32 mm). The Fleck group displayed significantly more microleakage compared to the Fuji Plus and Panavia F2.0 groups (P < 0.001) in both closed and open margins. In open margins, differences in microleakage between the Fuji Plus and G-Cem as well as between the G-Cem and Panavia F2.0 groups were significant (P < 0.001). In closed margins, only the G-Cem group displayed significantly more microleakage as compared to the Panavia F2.0 group (P < 0.05). Paired t-test results showed significantly more microleakage in open margins compared to closed margins, except in the Fuji Plus group (P = 0.539). Conclusions: Fuji Plus cement exhibited better sealing ability in closed and open margins compared to G-Cem and Fleck

  1. Overview: Damage resistance of graded ceramic restorative materials

    PubMed Central

    Zhang, Yu

    2012-01-01

    Improving mechanical response of materials is of great interest in a wide range of disciplines, including biomechanics, tribology, geology, optoelectronics, and nanotechnology. It has been long recognized that spatial gradients in surface composition and structure can improve the mechanical integrity of a material. This review surveys recent results of sliding-contact, flexural, and fatigue tests on graded ceramic materials from our laboratories and elsewhere. Although our findings are examined in the context of possible applications for next-generation, graded all-ceramic dental restorations, implications of our studies have broad impact on biomedical, civil, structural, and an array of other engineering applications. PMID:22778494

  2. Evaluation of dental adhesive systems with amalgam and resin composite restorations: comparison of microleakage and bond strength results.

    PubMed

    Neme, A L; Evans, D B; Maxson, B B

    2000-01-01

    A variety of laboratory tests have been developed to assist in predicting the clinical performance of dental restorative materials. Additionally, more than one methodology is in use for many types of tests performed in vitro. This project assessed and compared results derived from two specific laboratory testing methods, one for bond strength and one for microleakage. Seven multi-purpose dental adhesives were tested with the two methodologies in both amalgam and resin composite restorations. Bond strength was determined with a punch-out method in sections of human molar dentin. Microleakage was analyzed with a digital imaging system (Image-Pro Plus, Version 1.3) to determine the extent of dye penetration in Class V preparations centered at the CEJ on both the buccal and lingual surfaces of human molar teeth. There were 32 treatment groups (n = 10); seven experimental (dental adhesives) and one control (copal varnish, 37% phosphoric acid) followed by restoration with either amalgam or resin composite. Specimens were thermocycled 500 times in 5 degrees and 55 degrees C water with a one-minute dwell time. Bond strength and microleakage values were determined for each group. ANOVA and Student-Newman-Keuls tests demonstrated an interaction between restorative material and adhesive system with a significant difference among adhesives (p < 0.05). Using a multi-purpose adhesive system resulted in both a statistically significant increase in bond strength and a statistically significant decrease in extent of microleakage (p < 0.05). The effect of the adhesive upon both microleakage and bond strength was greater in the resin composite restorations than in the amalgam restorations. Bond strength testing was more discriminating than microleakage evaluation in identifying differences among materials.

  3. Effects of elevated temperatures on different restorative materials: An aid to forensic identification processes

    PubMed Central

    Pol, Chetan A.; Ghige, Suvarna K.; Gosavi, Suchitra R.; Hazarey, Vinay K.

    2015-01-01

    Background: Heat-induced alterations to dental and restorative materials can be of great interest to forensic dentistry. Knowing the specific optical behavior of dental materials can be of high importance as recognition of changes induced by high temperatures can lead to the determination of material which was used in a dental restoration, facilitating identification of burned human remains. Aim: To observe the effects of predetermined temperatures (200°C–400°C–600°C–800°C–1000°C) on unrestored teeth and different restorative materials macroscopically and then examine them under a stereomicroscope for the purpose of identification. Materials and Methods: The study was conducted on 375 extracted teeth which were divided into five groups of 75 teeth each as follows: group 1- unrestored teeth, group 2- teeth restored with all-ceramic crowns, Group 3- with class I silver amalgam filling, group 4- with class I composite restoration, and group 5- with class I glass ionomer cement restoration. Results: Unrestored and restored teeth display a series of specific macroscopic & stereomicroscopic structural changes for each range of temperature. Conclusion: Dental tissues and restorative materials undergo a series of changes which correlate well with the various temperatures to which they were exposed. These changes are a consequence of the nature of the materials and their physicochemical characteristics. PMID:26005305

  4. Wear of primary teeth caused by opposed all-ceramic or stainless steel crowns

    PubMed Central

    Bae, Ik-Hyun; Noh, Tae-Hwan; Ju, Sung-Won; Lee, Tae-Kyoung; Ahn, Jin-Soo; Jeong, Tae-Sung

    2016-01-01

    PURPOSE This study was conducted to evaluate the effects of full-coverage all-ceramic zirconia, lithium disilicate glass-ceramic, leucite glass-ceramic, or stainless steel crowns on antagonistic primary tooth wear. MATERIALS AND METHODS There were four study groups: the stainless steel (Steel) group, the leucite glass-ceramic (Leucite) group, the lithium disilicate glass-ceramic (Lithium) group, and the monolithic zirconia (Zirconia) group. Ten flat crown specimens were prepared per group; opposing teeth were prepared using primary canines. A wear test was conducted over 100,000 chewing cycles using a dual-axis chewing simulator and a 50 N masticating force, and wear losses of antagonistic teeth and restorative materials were calculated using a three-dimensional profiling system and an electronic scale, respectively. Statistical significance was determined using One-way ANOVA and Tukey's test (P<.05). RESULTS The Leucite group (2.670±1.471 mm3) showed the greatest amount of antagonist tooth wear, followed by in decreasing order by the Lithium (2.042±0.696 mm3), Zirconia (1.426±0.477 mm3), and Steel groups (0.397±0.192 mm3). Mean volume losses in the Leucite and Lithium groups were significantly greater than in the Steel group (P<.05). No significant difference was observed between mean volume losses in the Zirconia and Steel groups (P>.05). CONCLUSION Leucite glass-ceramic and lithium disilicate glass-ceramic cause more primary tooth wear than stainless steel or zirconia. PMID:26949487

  5. Effects of mercury release from amalgam dental restorations during cremation on soil mercury levels of three New Zealand crematoria

    SciTech Connect

    Nieschmidt, A.K.; Kim, N.D.

    1997-05-01

    A vast amount of research has been undertaken in the last 15-20 years on the corrosion reactions occurring in dental amalgam, release of mercury from amalgam restorations, and the toxic effects of this released mercury on the human body. However, one environmental aspect of amalgam dental restorations that has not received a great deal of attention is the release of mercury during cremation. Mercury is liberated during cremation both because dental amalgams are unstable at cremation temperatures (650-700{degrees}C) and because the free mercury metal is highly volatile. In New Zealand, 58% of deaths are followed by cremation and this figure is likely to rise in the future. This increasing use of cremation as the method of corpse disposal, coupled with the fact that each amalgam restoration is approximately 50% mercury, implies that a significant amount of mercury may be emitted into the environment every year. This study examines mercury released from crematoria in New Zealand. 20 refs., 2 figs., 5 tabs.

  6. Long-term cytotoxicity of resin-based dental restorative materials.

    PubMed

    Bouillaguet, S; Shaw, L; Gonzalez, L; Wataha, J C; Krejci, I

    2002-01-01

    Highly filled composites, Ormocers (organically modified ceramics) and 'smart' materials have been developed to overcome the polymerization shrinkage problems of conventional composite materials. The purpose of the current study was to investigate the effect of longer-term (up to 8 weeks) ageing of these resin-based dental restorative materials and determine the effect of post-curing on cytotoxicity. Twelve discs of each material (Colombus/IDR, Definite/Degussa, Ariston pHc/Vivadent) were either light-cured (Lc) or light-cured and post-cured (Pc). For cytotoxicity testing, the discs were placed in contact with cell culture medium (DMEM) and incubated at 37 degrees C. Extracts from composite materials were collected after 24 h and weekly over a time period of 8 weeks. Cytotoxicity of the eluates to cultured fibroblasts (Balb/c3T3) were measured by the succinic dehydrogenase (SDH) activity (MTT assay) and the results expressed in percentage of negative controls (Teflon discs). The results showed that ageing significantly influenced the cytotoxicity of the materials. Except for Ariston pHc, materials were less cytotoxic after 8 weeks of ageing than they were in early intervals and post-curing was not generally useful in reducing cytotoxicity. The Ariston pHc was initially moderately toxic, but then become highly cytotoxic for 5 weeks before returning to initial levels. The current study demonstrated the importance of assessing the cytotoxicity of resin composite materials at multiple times.

  7. Water absorption, dimensional change and radial pressure in resin matrix dental restorative materials.

    PubMed

    McCabe, John F; Rusby, Sandra

    2004-08-01

    The purpose of this work was to study the relationship between water absorption, dimensional change (swelling) under cavity constraint and radial stress generation in resin matrix dental restorative materials. Water absorption was determined on disc specimens whilst swelling was determined on samples of materials restrained within cavities cut in cast polymethylmethacrylate and pressure generated was determined using a 'push-out' test. Four commercially available resin matrix materials were used. A giomer material gave significantly greater water absorption than two compomers and a fluoride releasing composite (p<0.05). The giomer material was the only material which produced a significant degree of swelling (p<0.05) when restrained within a cavity. The giomer product produced the greatest radial pressure (over 20 MPa in 1 month) following water storage, however a significant pressure generation was also observed for other materials despite their much lower water absorption values. The mechanism of water absorption and the amount of water absorbed determine the dimensional changes and radial pressure generated by resin matrix materials in a moist environment.

  8. Mechanistic aspects of fracture and fatigue in resin based dental restorative composites

    NASA Astrophysics Data System (ADS)

    Shah, Minalben B.

    For resin based dental restorative composites, one of the major challenges is to optimize the balance between mechanical and optical properties. Although fracture is the second leading cause of dental restorative failures, very limited mechanistic understanding exists on a microscopic level. In the present study, the fracture properties and mechanisms of two commercial dental resin composites with different microstructures are examined using double notched four point beam bending and pre-cracked compact-tension, C(T), specimens. Four point bend flexural strength was also measured using un-notched beam samples. The first material is a microhybrid composite that combines a range of nano and micro scale filler particles to give an average particle size of 0.6 mum, while the second is a nanofill composite reinforced entirely with nano particles and their agglomerates. The influences of 60 days water hydration and a post-cure heat treatment were also examined. Fracture resistance curve (R-curve) experiments have demonstrated the microhybrid composite to be more fracture resistant than the nanofill composite in both as-processed and hydrated conditions. Rising fracture resistance with crack extension was observed in all specimens, independent of the environmental conditions. Compared to the as-processed condition, a significant reduction in the peak toughness was observed for the nanofill composite after 60 days of water aging. Hydration lowered flexural strength of both composites which was attributed to hydrolytic matrix degradation with additional interfacial debonding causing larger strength decrease in the nanofill. Optical and SEM observations revealed an interparticle matrix crack path promoting crack deflection as a toughening mechanism in all cases except the hydrated nanofill which showed particle-matrix debonding. Crack bridging was another observed extrinsic toughening mechanism that was believed to be responsible for the rising fracture resistance curve (R

  9. Assessment of exposures and potential risks to the US adult population from wear (attrition and abrasion) of gold and ceramic dental restorations.

    PubMed

    Richardson, G Mark; Clemow, Scott R; Peters, Rachel E; James, Kyle J; Siciliano, Steven D

    2016-01-01

    Little has been published on the chemical exposures and risks of dental restorative materials other than from dental amalgam and composite resins. Here we provide the first exposure and risk assessment for gold (Au) alloy and ceramic restorative materials. Based on the 2001-2004 US National Health and Nutrition Examination Survey (NHANES), we assessed the exposure of US adults to the components of Au alloy and ceramic dental restorations owing to dental material wear. Silver (Ag) is the most problematic component of Au alloy restorations, owing to a combination of toxicity and proportional composition. It was estimated that adults could possess an average of four tooth surfaces restored with Au alloy before exceeding, on average, the reference exposure level (REL) for Ag. Lithium (Li) is the most problematic component of dental ceramics. It was estimated that adults could possess an average of 15 tooth surfaces restored with ceramics before exceeding the REL for Li. Relative risks of chemical exposures from dental materials decrease in the following order: Amalgam>Au alloys>ceramics>composite resins.

  10. Curriculum time compared to clinical procedures in amalgam and composite posterior restorations in U.S. dental schools: a preliminary study.

    PubMed

    Rey, Rosalia; Nimmo, Susan; Childs, Gail S; Behar-Horenstein, Linda S

    2015-03-01

    Dental clinicians have an expanding range of biomaterial choices for restoring tooth structure. Scientific developments in cariology, advances in dental biomaterials, and patients' esthetic concerns have led to a reduction in amalgam restorations and an increase in composite restorations. The aim of this study was to compare teaching time with students' clinical procedures in amalgam and composite posterior restorations in dental schools across the United States. Academic deans in 60 schools were invited to complete a survey that asked for the amount of instructional time for amalgam and composite posterior restorations and the number of clinical restorations performed by their Classes of 2009, 2010, and 2011. Of these 60, 12 returned surveys with complete data, for a 20% response rate. Responses from these schools showed little change in lecture and preclinical laboratory instruction from 2009 to 2011. There was a slight increase in two-surface restorations for both amalgam and composites; however, the total number of reported composite and amalgam restorations remained the same. Of 204,864 restorations reported, 53% were composite, and 47% were amalgam. There were twice as many multisurface large or complex amalgam restorations as composites. One-surface composite restorations exceeded amalgams. Among the participating schools, there was little to no change between curriculum time and clinical procedures. Findings from this preliminary study reflect a modest increase in two-surface resin-based restorations placed by dental students from 2009 to 2011 and little change in curricular time devoted to teaching amalgam restorations. The total number of posterior composite restorations placed by students in these schools was slightly higher than amalgams.

  11. Teaching atraumatic restorative treatment in U.S. dental schools: a survey of predoctoral pediatric dentistry program directors.

    PubMed

    Kateeb, Elham T; Warren, John J; Damiano, Peter; Momany, Elizabeth; Kanellis, Michael; Weber-Gasparoni, Karin; Ansley, Tim

    2013-10-01

    The International Dental Federation and World Health Organization have promoted the use of Atraumatic Restorative Treatment (ART) in modern clinical settings worldwide. In the United States, the practice of ART is not believed to be widely used, which may be a result of little attention given to ART training in predoctoral pediatric dentistry curricula in U.S. dental schools. This study investigated the extent of clinical and didactic instruction on ART provided in U.S. dental schools by surveying the predoctoral pediatric dentistry programs in 2010. Of the fifty-seven directors asked to complete the survey, forty-four responded for a response rate of 77 percent. Of these forty-four programs, 66 percent reported providing clinical training on ART, though only 14 percent provide this training often or very often. The types of ART training provided often or very often included interim treatment (18 percent) and single-surface cavities (14 percent) in primary teeth. However, ART was said to be rarely taught as a definitive treatment in permanent teeth (2 percent). Attitude was a major predictor, for clinical training provided and using professional guidelines in treatment decisions were associated with a positive attitude towards ART. These predoctoral pediatric dentistry programs used ART mainly in primary, anterior, and single-surface cavities and as interim treatment. As ART increases access of children to dental care, the incorporation of the ART approach into the curricula of U.S. dental schools should be facilitated by professional organizations.

  12. Catechol-Functionalized Synthetic Polymer as a Dental Adhesive to Contaminated Dentin Surface for a Composite Restoration.

    PubMed

    Lee, Sang-Bae; González-Cabezas, Carlos; Kim, Kwang-Mahn; Kim, Kyoung-Nam; Kuroda, Kenichi

    2015-08-10

    This study reports a synthetic polymer functionalized with catechol groups as dental adhesives. We hypothesize that a catechol-functionalized polymer functions as a dental adhesive for wet dentin surfaces, potentially eliminating the complications associated with saliva contamination. We prepared a random copolymer containing catechol and methoxyethyl groups in the side chains. The mechanical and adhesive properties of the polymer to dentin surface in the presence of water and salivary components were determined. It was found that the new polymer combined with an Fe(3+) additive improved bond strength of a commercial dental adhesive to artificial saliva contaminated dentin surface as compared to a control sample without the polymer. Histological analysis of the bonding structures showed no leakage pattern, probably due to the formation of Fe-catechol complexes, which reinforce the bonding structures. Cytotoxicity test showed that the polymers did not inhibit human gingival fibroblast cells proliferation. Results from this study suggest a potential to reduce failure of dental restorations due to saliva contamination using catechol-functionalized polymers as dental adhesives.

  13. Catechol-Functionalized Synthetic Polymer as a Dental Adhesive to Contaminated Dentin Surface for a Composite Restoration

    PubMed Central

    2015-01-01

    This study reports a synthetic polymer functionalized with catechol groups as dental adhesives. We hypothesize that a catechol-functionalized polymer functions as a dental adhesive for wet dentin surfaces, potentially eliminating the complications associated with saliva contamination. We prepared a random copolymer containing catechol and methoxyethyl groups in the side chains. The mechanical and adhesive properties of the polymer to dentin surface in the presence of water and salivary components were determined. It was found that the new polymer combined with an Fe3+ additive improved bond strength of a commercial dental adhesive to artificial saliva contaminated dentin surface as compared to a control sample without the polymer. Histological analysis of the bonding structures showed no leakage pattern, probably due to the formation of Fe–catechol complexes, which reinforce the bonding structures. Cytotoxicity test showed that the polymers did not inhibit human gingival fibroblast cells proliferation. Results from this study suggest a potential to reduce failure of dental restorations due to saliva contamination using catechol-functionalized polymers as dental adhesives. PMID:26176305

  14. Digital data acquisition for a CAD/CAM-fabricated titanium framework and zirconium oxide restorations for an implant-supported fixed complete dental prosthesis.

    PubMed

    Lin, Wei-Shao; Metz, Michael J; Pollini, Adrien; Ntounis, Athanasios; Morton, Dean

    2014-12-01

    This dental technique report describes a digital workflow with digital data acquisition at the implant level, computer-aided design and computer-aided manufacturing fabricated, tissue-colored, anodized titanium framework, individually luted zirconium oxide restorations, and autopolymerizing injection-molded acrylic resin to fabricate an implant-supported, metal-ceramic-resin fixed complete dental prosthesis in an edentulous mandible. The 1-step computer-aided design and computer-aided manufacturing fabrication of titanium framework and zirconium oxide restorations can provide a cost-effective alternative to the conventional metal-resin fixed complete dental prosthesis.

  15. Assessing ex vivo dental biofilms and in vivo composite restorations using cross-polarization optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Jones, R.; Aparicio, C.; Chityala, R.; Chen, R.; Fok, A.; Rudney, J.

    2012-01-01

    A cross-polarization 1310-nm optical coherence tomography system (CP-OCT), using a beam splitter based design, was used to assess ex vivo growth of complex multi-species dental biofilms. These biofilm microcosms were derived from plaque samples along the interface of composite or amalgam restoration in children with a history of early childhood caries. This paper presents a method of measuring the mean biofilm height of mature biofilms using CP-OCT. For our in vivo application, the novel swept source based CP-OCT intraoral probe (Santec Co. Komaki, Japan) dimensions and system image acquisition speed (20 image frames/second) allowed imaging pediatric subjects as young as 4 years old. The subsurface enamel under the interface of composite resin restorations of pediatric subjects were imaged using CP-OCT. Cavitated secondary caries is clearly evident from sound resin composite restorations.

  16. Influence of cyclic loading on the fracture toughness and load bearing capacities of all-ceramic crowns

    PubMed Central

    Wang, Rao-Rao; Lu, Cheng-Lin; Wang, Gang; Zhang, Dong-Sheng

    2014-01-01

    The purpose of this study was to investigate how cyclic loading influenced the fracture toughness of hot-press lithium disilicate and zirconia core materials and whether there was an increase in the propensity for crown failure. Two types of all-ceramic crowns including the IPS e.max Press system (n=24) and the Lava zirconia system (n=24), were selected. Sectioned specimens were subjected to cyclic loading with the maximum magnitude of 200 N (R=0.1) until two million cycles. The material properties including Young's modulus (E) and hardness (H) and the fracture toughness (KIC) of the core materials were evaluated using indentation methods (n=12 each). The load-bearing capacities of the specimens were examined by means of monotonic load to fracture (n=12 each). It was found that the material properties, including E, H and KIC, of the two types of dental ceramics, were reduced. Statistical analysis indicated that there were no significant influences of fatigue loading on material properties E and H for both types of dental ceramics or KIC for zirconia, while for the IPS e.max Press core, KIC, which was parallel to the direction of the lithium disilicate crystals, was significantly reduced (P=0.001). A conclusion was drawn that zirconia possesses high mechanical reliability and sustainable capacity to resist fatigue loading, while fatigue loading remarkably degraded the anisotropic mechanical behaviour of hot-press lithium disilicate ceramics. PMID:24335786

  17. Optical coherence tomography based imaging of dental demineralisation and cavity restoration in 840 nm and 1310 nm wavelength regions

    NASA Astrophysics Data System (ADS)

    Damodaran, Vani; Rao, Suresh Ranga; Vasa, Nilesh J.

    2016-08-01

    In this paper, a study of in-house built optical coherence tomography (OCT) system with a wavelength of 840 nm for imaging of dental caries, progress in demineralisation and cavity restoration is presented. The caries when imaged with the 840 nm OCT system showed minute demineralisation in the order of 5 μm. The OCT system was also proposed to study the growth of lesion and this was demonstrated by artificially inducing caries with a demineralisation solution of pH 4.8. The progress of carious lesion to a depth of about 50-60 μm after 60 hours of demineralisation was clearly observed with the 840 nm OCT system. The tooth samples were subjected to accelerated demineralisation condition at pH of approximately 2.3 to study the adverse effects and the onset of cavity formation was clearly observed. The restoration of cavity was also studied by employing different restorative materials (filled and unfilled). In the case of restoration without filler material (unfilled), the restoration boundaries were clearly observed. Overall, results were comparable with that of the widely used 1310 nm OCT system. In the case of restoration with filler material, the 1310 nm OCT imaging displayed better imaging capacity due to lower scattering than 840 nm imaging.

  18. Enzymatic responses of human deciduous pulpal fibroblasts to dental restorative materials.

    PubMed

    Chen, Chern-Chin; Chen, Robert Cheng-Shen; Huang, Shun-Te

    2002-06-05

    The purpose of this study was to evaluate the responses of succinic dehydrogenase (SDH) and alkaline phosphatase (ALP) activities of human deciduous teeth pulpal fibroblasts (HDPF) to dental restorative materials. Tested materials included Z100 (3M), Dyract (Dentsply), FujiII (GC), and FujiIILC (GC). IRM (Dentsply) and culture medium (MD) alone were used as positive and negative controls, respectively. Specimens 6 mm (diameter) x 3 mm were prepared in accordance with manufacturers' instructions. For light-cured materials, specimens were light cured for 40 s on both sides under a celluloid strip. For chemical-cured materials, specimens were allowed to set at room temperature for 15 min. The specimens were immersed in 1 mL of culture medium without serum for 24 h at room temperature. The extracts were filtered through 0.22-mm filters. HDPF (10,000 cells/well) was incubated with 100 microL of extract and 20 % FBS in a 96-well plate for 24 h in a 37 degrees, 5 % CO(2) incubator. Six wells per material were prepared. Optical density (OD) of SDH and ALP of HDPF were measured by a spectrophotometer. The means were analyzed by ANOVA and then a Duncan Test. The ranking of OD of SDH was IRM < FujiIILC < FujiII = Z100 < Dyract < MD (p < 0.05). The ranking of OD of ALP was IRM < Z100 = Dyract < FujiII < FujiIILC < MD (p < 0.05). The result showed that all of the tested restorative materials were cytotoxic to human deciduous pulpal fibroblasts. The cytotoxicity of resin-modified glass ionomer cements (FujiIILC) was stronger than that of traditional glass ionomer cements (FujiII) and composite resin (Z100), and that of compomer (Dyract) was the weakest. On the contrary, ALP activities of resin-modified glass ionomer cements (FujiIILC) and composite resin (Z100) were higher than those of traditional glass ionomer cements (FujiII), while those of compomer (Dyract) were the lowest. It is concluded that, in this study, FujiIILC was the most cytotoxic material and the least

  19. Biphenyl liquid crystalline epoxy resin as a low-shrinkage resin-based dental restorative nanocomposite.

    PubMed

    Hsu, Sheng-Hao; Chen, Rung-Shu; Chang, Yuan-Ling; Chen, Min-Huey; Cheng, Kuo-Chung; Su, Wei-Fang

    2012-11-01

    Low-shrinkage resin-based photocurable liquid crystalline epoxy nanocomposite has been investigated with regard to its application as a dental restoration material. The nanocomposite consists of an organic matrix and an inorganic reinforcing filler. The organic matrix is made of liquid crystalline biphenyl epoxy resin (BP), an epoxy resin consisting of cyclohexylmethyl-3,4-epoxycyclohexanecarboxylate (ECH), the photoinitiator 4-octylphenyl phenyliodonium hexafluoroantimonate and the photosensitizer champhorquinone. The inorganic filler is silica nanoparticles (∼70-100 nm). The nanoparticles were modified by an epoxy silane of γ-glycidoxypropyltrimethoxysilane to be compatible with the organic matrix and to chemically bond with the organic matrix after photo curing. By incorporating the BP liquid crystalline (LC) epoxy resin into conventional ECH epoxy resin, the nanocomposite has improved hardness, flexural modulus, water absorption and coefficient of thermal expansion. Although the incorporation of silica filler may dilute the reinforcing effect of crystalline BP, a high silica filler content (∼42 vol.%) was found to increase the physical and chemical properties of the nanocomposite due to the formation of unique microstructures. The microstructure of nanoparticle embedded layers was observed in the nanocomposite using scanning and transmission electron microscopy. This unique microstructure indicates that the crystalline BP and nanoparticles support each other and result in outstanding mechanical properties. The crystalline BP in the LC epoxy resin-based nanocomposite was partially melted during exothermic photopolymerization, and the resin expanded via an order-to-disorder transition. Thus, the post-gelation shrinkage of the LC epoxy resin-based nanocomposite is greatly reduced, ∼50.6% less than in commercialized methacrylate resin-based composites. This LC epoxy nanocomposite demonstrates good physical and chemical properties and good biocompatibility

  20. CHIPPING FRACTURE RESISTANCE OF DENTAL CAD/CAM RESTORATIVE MATERIALS: PART I, PROCEDURES AND RESULTS

    PubMed Central

    Quinn, G. D.; Giuseppetti, A. A.; Hoffman, K. H.

    2014-01-01

    Objective The edge chipping test was used to measure the fracture resistance of CAD/CAM dental restoration ceramics and resin composites. Methods An edge chipping machine was used to evaluate six materials including one feldspathic porcelain, two glass ceramics, a filled resin-composite, a yttria-stabilized zirconia, and a new ceramic-resin composite material. Force versus edge distance data were collected over a broad range of forces and distances. Data were analyzed by several approaches and several chipping resistance parameters were evaluated. The effects of using different indenter types were explored. Results The force versus distance trends were usually nonlinear with good fits to a power law equation with exponents usually ranging from 1.2 to 1.9. The order of chipping resistance (from least to greatest) was: feldspathic porcelain and a leucite glass ceramic (which were similar), followed by the lithium disilicate glass ceramic and the two resin composites (which were similar), and finally the zirconia which had the greatest resistance to chipping. Chipping with a Vickers indenter required 28% to 45% more force than with the sharp conical 120° indenter. The two indenters rank materials approximately the same way. The power law exponents were very similar for the two indenters for a particular material, but the exponents varied with material. The Rockwell C indenter gives different power law trends and rankings. Significance Despite the variations in the trends and indenters, simple comparisons between materials can be made by chipping with sharp conical 120° or Vickers indenters at 0.50 mm. Broad distance ranges are recommended for trend evaluation. PMID:24685178

  1. Detection of composite resin restorations using an ultraviolet light-emitting diode flashlight during forensic dental identification.

    PubMed

    Guzy, Gerald; Clayton, Mary Ann

    2013-06-01

    With the increased use of composite resin and the decreased use of amalgam as a dental restorative material, the forensic dental identification of unidentified human remains has become more difficult. Various methods have been used to detect the presence of composite resin restorations including dyes, forensic alternative light sources, quantitative light-induced fluorescence, and ultraviolet lights. Although these methods may be helpful, the expense of the equipment, the electrical requirements, and the need for water to wash the dye from the mouth may make these methods impractical especially in a temporary morgue situation during a mass disaster. The fluorescent properties of composite resins, when exposed to ultraviolet light, are well documented. Standard tube ultraviolet lights have been used to detect the presence of composite resin, but these lights are large and bulky, and the tubes are fragile. The development of ultraviolet light emitting diode flashlights has provided forensic odontologists with a tool that is small, inexpensive, and battery operated. The two forensic dental identification cases described here demonstrate the value of ultraviolet light emitting diode flashlights as an adjunct to a careful clinical and radiographic examination.

  2. Optical properties of dental restorative materials in the wavelength range 400 to 700 nm for the simulation of color perception

    NASA Astrophysics Data System (ADS)

    Friebel, Moritz; Povel, Kirsten; Cappius, Hans-Joachim; Helfmann, Jürgen; Meinke, Martina

    2009-09-01

    Aesthetic restorations require dental restorative materials to have optical properties very similar to those of the teeth. A method is developed to this end to determine the optical parameters absorption coefficient μa, scattering coefficient μs, anisotropy factor g, and effective scattering coefficient μs' of dental restorative materials. The method includes sample preparation and measurements of transmittance and reflectance in an integrating sphere spectrometer followed by inverse Monte Carlo simulations. Using this method the intrinsic optical parameters are determined for shade B2 of the light-activated composites TPH® Spectrum®, Esthet-X®, and the Ormocer® Definite® in the wavelength range 400 to 700 nm. By using the determined parameters μa, μs, and g together with an appropriate phase function, the reflectance of samples with 1-mm layer thickness and shade B2 could be predicted with a very high degree of accuracy using a forward Monte Carlo simulation. The color perception was calculated from the simulated reflectance according to the CIELAB system. We initiate the compilation of a data pool of optical parameters that in the future will enable calculation models to be used as a basis for optimization of the optical approximation of the natural tooth, and the composition of new materials and their production process.

  3. Optical properties of dental restorative materials in the wavelength range 400 to 700 nm for the simulation of color perception.

    PubMed

    Friebel, Moritz; Povel, Kirsten; Cappius, Hans-Joachim; Helfmann, Jürgen; Meinke, Martina

    2009-01-01

    Aesthetic restorations require dental restorative materials to have optical properties very similar to those of the teeth. A method is developed to this end to determine the optical parameters absorption coefficient mu(a), scattering coefficient mu(s), anisotropy factor g, and effective scattering coefficient mu(s) (') of dental restorative materials. The method includes sample preparation and measurements of transmittance and reflectance in an integrating sphere spectrometer followed by inverse Monte Carlo simulations. Using this method the intrinsic optical parameters are determined for shade B2 of the light-activated composites TPH((R)) Spectrum, Esthet-X, and the Ormocer Definite in the wavelength range 400 to 700 nm. By using the determined parameters mu(a), mu(s), and g together with an appropriate phase function, the reflectance of samples with 1-mm layer thickness and shade B2 could be predicted with a very high degree of accuracy using a forward Monte Carlo simulation. The color perception was calculated from the simulated reflectance according to the CIELAB system. We initiate the compilation of a data pool of optical parameters that in the future will enable calculation models to be used as a basis for optimization of the optical approximation of the natural tooth, and the composition of new materials and their production process.

  4. Simulation of clinical fractures for three different all-ceramic crowns

    PubMed Central

    Øilo, Marit; Kvam, Ketil; Gjerdet, Nils R

    2014-01-01

    Comparison of fracture strength and fracture modes of different all-ceramic crown systems is not straightforward. Established methods for reliable testing of all-ceramic crowns are not currently available. Published in-vitro tests rarely simulate clinical failure modes and are therefore unsuited to distinguish between the materials. The in-vivo trials usually lack assessment of failure modes. Fractographic analyses show that clinical crowns usually fail from cracks initiating in the cervical margins, whereas in-vitro specimens fail from contact damage at the occlusal loading point. The aim of this study was to compare three all-ceramic systems using a clinically relevant test method that is able to simulate clinical failure modes. Ten incisor crowns of three types of all-ceramic systems were exposed to soft loading until fracture. The initiation and propagation of cracks in these crowns were compared with those of a reference group of crowns that failed during clinical use. All crowns fractured in a manner similar to fracture of the clinical reference crowns. The zirconia crowns fractured at statistically significantly higher loads than alumina and glass-ceramic crowns. Fracture initiation was in the core material, cervically in the approximal areas. PMID:24698209

  5. The Efficacy of Noncontingent Escape for Decreasing Children's Disruptive Behavior during Restorative Dental Treatment

    ERIC Educational Resources Information Center

    O'Callaghan, Patrick M.; Allen, Keith D.; Powell, Shawn; Salama, Fouad

    2006-01-01

    We evaluated the effectiveness of a dentist-implemented behavioral intervention in which brief escape from dental treatment was provided on a regular basis, independent of the child's behavior. Within a multiple baseline design across subjects, 5 children, ages 4 to 7 years, were provided with temporary escape from dental treatment on a fixed-time…

  6. Dental restorative biomaterials induce glutathione depletion in cultured human gingival fibroblast: protective effect of N-acetyl cysteine.

    PubMed

    Stanislawski, L; Soheili-Majd, E; Perianin, A; Goldberg, M

    2000-09-05

    Eight biomaterials eluted from four different types of dental restorative biomaterials, that is, from glass-ionomer cement (GIC: Ketac-fil and Fuji II), resin-modified glass ionomer cement (RM-GIC: Fuji II LC and Photac-fil), composite (Z100 MP and Tetric-flow), and compomer (Compoglass F and F-2000), were studied for their cytotoxic properties in relation to glutathione (GSH) content in cultured human gingival fibroblasts. Z100 MP, Tetric-flow, and Compoglass F were less cytotoxic than the others, with a toxic concentration of 50% (TC 50) > 24% (of eluate), as determined by the MTT test. F-2000, Tetric-flow, and the other biomaterials were relatively more cytotoxic (TC 50 = 9-16%). With the exception of Z100 MP, all the biomaterials induced a depletion of cellular glutathione (GSH) that was variable depending upon the biomaterial eluates. The strongest GSH depletion was with F-2000, Fuji II, and Photac-fil. GSH depletion, with Compoglass and F-2000, was rapid-detectable after one h of cell treatment and complete within 3 h-whereas a longer period of incubation was required for the other biomaterials. Interestingly, the drug cytotoxic effects induced by all the biomaterials were prevented by cell treatment with the antioxidant N-acetylcysteine (NAC). This study provides evidence that the cytotoxic property of dental restorative biomaterials is associated with depletion of the glutathione level in gingival fibroblasts. While the molecular mechanisms of this phenomenon require further investigations, our data suggest that NAC may be useful in preventing the cellular damage induced by dental restorative biomaterials.

  7. Inlay-retained zirconia fixed dental prosthesis: clinical and laboratory procedures.

    PubMed

    Monaco, Carlo; Cardelli, Paolo; Bolognesi, Michele; Scotti, Roberto; Ozcan, Mutlu

    2012-01-01

    Many treatment options are currently available for single tooth replacement, such as metal-ceramic, all-ceramic, direct or indirect fiber-reinforced composite fixed dental prostheses (FDPs) or implants. Inlay-retained FDPs could be indicated especially when adjacent teeth have preexisting restorations and where implant placement is not possible or not indicated. In such cases, indication of both metal-ceramic and fiber-reinforced composite FDPs has certain disadvantages. This paper describes the use of all-ceramic inlay-retained FDPs with zirconia frameworks, veneered with a press-on technique. The retainer margins were made of pressed ceramic to make adhesive luting possible. In deep cavities, a full contour press-on ceramic all around the retainers increased the available surface area for the adhesive approach.

  8. Clinical Investigation of a New Bulk Fill Composite Resin in the Restoration of Posterior Teeth

    ClinicalTrials.gov

    2016-09-07

    Dental Restoration Failure of Marginal Integrity; Dental Caries; Unrepairable Overhanging of Dental Restorative Materials; Poor Aesthetics of Existing Restoration; Secondary Dental Caries Associated With Failed or Defective Dental Restorations; Fractured Dental Restorative Materials Without Loss of Materials; Fracture of Dental Restorative Materials With Loss of Material

  9. Non-thermal Atmospheric Plasma Treatment for Deactivation of Oral Bacteria and Improvement of Dental Composite Restoration

    NASA Astrophysics Data System (ADS)

    Yu, Qing Song; Li, H.; Ritts, A. C.; Yang, B.; Chen, M.; Hong, L.; Xu, C.; Yao, X.; Wang, Y.

    This paper reviews our recent research results of using non-thermal ­atmospheric plasmas for oral bacterial deactivation and for composite restoration improvement. Oral bacteria of Streptococcus mutans (S. mutans) and Lactobacillus acidophilus (L. acidophilus) with an initial bacterial population density between 1.0 × 108 and 5.0 × 108 cfu/ml were seeded on various media and their survivability with plasma exposure was examined. The plasma exposure time for a 99.9999% cell reduction was less than 15 s for S. mutans and within 5 min for L. acidophilus. To evaluate the dentin/composite interfacial bonding, extracted unerupted human third molars were used by removing the crowns and etching the exposed dentin surfaces with 35% phosphoric acid gel. After dental composite application and light curing, the teeth were then sectioned into micro-bars as the specimens for microtensile test. Student Newman Keuls (SNK) tests showed that the bonding strength of the composite restoration to peripheral dentin was significantly increased (by 64%) after 30 s plasma treatment of the dentin surfaces. These findings indicated that non-thermal atmospheric plasma technology is very promising for dental clinical applications.

  10. Evaluation of an all-ceramic tubesheet assembly for a hot gas filter

    SciTech Connect

    Bitner, J.L.; Mallett, R.H.; Eggerstedt, P.M.; Swindeman, R.W.

    1997-12-01

    A 10-inch thick, all-ceramic tubesheet design is evaluated for differential pressure and thermal conditions. Primary stresses from differential pressure are well within a safe allowable. The calculated peak thermal stresses at local discontinuities approach the modules of rupture for the ceramic material. Kiln tests were performed to demonstrate differential temperatures between hot center and cooler rim do not cause failures or visible tensile cracks. There appear to be mitigating mechanisms and design features in the Industrial Filter and Pump (IF and P) Mfg. Co. all-ceramic tubesheet design concept that add forgiveness in accommodating differential pressure and thermal loading stresses. A material characterization program on the ceramic materials is recommended.

  11. Chairside Fabrication of an All-Ceramic Partial Crown Using a Zirconia-Reinforced Lithium Silicate Ceramic

    PubMed Central

    Pabel, Anne-Kathrin; Rödiger, Matthias

    2016-01-01

    The chairside fabrication of a monolithic partial crown using a zirconia-reinforced lithium silicate (ZLS) ceramic is described. The fully digitized model-free workflow in a dental practice is possible due to the use of a powder-free intraoral scanner and the computer-aided design/computer-assisted manufacturing (CAD/CAM) of the restorations. The innovative ZLS material offers a singular combination of fracture strength (>370 Mpa), optimum polishing characteristics, and excellent optical properties. Therefore, this ceramic is an interesting alternative material for monolithic restorations produced in a digital workflow. PMID:27042362

  12. Marginal and internal fit of heat pressed versus CAD/CAM fabricated all-ceramic onlays after exposure to thermo-mechanical fatigue

    PubMed Central

    Guess, Petra C.; Vagopoulou, Thaleia; Zhang, Yu; Wolkewitz, Martin; Strub, Joerg R.

    2015-01-01

    Objectives The aim of the study was to evaluate the marginal and internal fit of heat-pressed and CAD/CAM fabricated all-ceramic onlays before and after luting as well as after thermo-mechanical fatigue. Materials and Methods Seventy-two caries-free, extracted human mandibular molars were randomly divided into three groups (n=24/group). All teeth received an onlay preparation with a mesio-occlusal-distal inlay cavity and an occlusal reduction of all cusps. Teeth were restored with heat-pressed IPS-e.max-Press* (IP, *Ivoclar-Vivadent) and Vita-PM9 (VP, Vita-Zahnfabrik) as well as CAD/CAM fabricated IPS-e.max-CAD* (IC, Cerec 3D/InLab/Sirona) all-ceramic materials. After cementation with a dual-polymerizing resin cement (VariolinkII*), all restorations were subjected to mouth-motion fatigue (98N, 1.2 million cycles; 5°C/55°C). Marginal fit discrepancies were examined on epoxy replicas before and after luting as well as after fatigue at 200x magnification. Internal fit was evaluated by multiple sectioning technique. For the statistical analysis, a linear model was fitted with accounting for repeated measurements. Results Adhesive cementation of onlays resulted in significantly increased marginal gap values in all groups, whereas thermo-mechanical fatigue had no effect. Marginal gap values of all test groups were equal after fatigue exposure. Internal discrepancies of CAD/CAM fabricated restorations were significantly higher than both press manufactured onlays. Conclusions Mean marginal gap values of the investigated onlays before and after luting as well as after fatigue were within the clinically acceptable range. Marginal fit was not affected by the investigated heat-press versus CAD/CAM fabrication technique. Press fabrication resulted in a superior internal fit of onlays as compared to the CAD/CAM technique. Clinical Relevance Clinical requirements of 100 μm for marginal fit were fulfilled by the heat-press as well as by the CAD/CAM fabricated all-ceramic onlays

  13. Forensic or archaeological issue: is chemical analysis of dental restorations helpful in assessing time since death and identification of skeletonized human remains?

    PubMed

    Zelic, Ksenija; Djonic, Danijela; Neskovic, Olivera; Stoiljkovic, Milovan; Nikolic, Slobodan; Zivkovic, Vladimir; Djuric, Marija

    2013-09-01

    In 2011, small mass grave with completely skeletonized remains was discovered in Belgrade suburb. An eyewitness claimed that skeletons belonged to German soldiers killed in WWII. Anthropologists were engaged to investigate whether the skeletal remains correspond to the indicated German group or represent more recent case requiring court trial. Numerous dental restorations were noticed. Owing to the fact that different dental materials were used in dental practice at certain times, the aim of this study was to explore whether analysis of dental restorations could help in identification and estimation of time since death. Inductively coupled plasma optical emission spectrometry revealed that dental fillings corresponded to copper amalgam, conventional silver amalgam, silicophosphate cement, and zinc phosphate cement. Chemical results combined with anthropological and historical facts suggest that the individuals lived before the 1960s in country with well-developed dental service at that time. Therefore, chemical analysis of dental fillings was useful to distinguish between skeletal remains that are too old to be of forensic interest and the remains relevant to legal investigations.

  14. Ceramics in Restorative and Prosthetic DENTISTRY1

    NASA Astrophysics Data System (ADS)

    Kelly, J. Robert

    1997-08-01

    This review is intended to provide the ceramic engineer with information about the history and current use of ceramics in dentistry, contemporary research topics, and potential research agenda. Background material includes intra-oral design considerations, descriptions of ceramic dental components, and the origin, composition, and microstructure of current dental ceramics. Attention is paid to efforts involving net-shape processing, machining as a forming method, and the analysis of clinical failure. A rationale is presented for the further development of all-ceramic restorative systems. Current research topics receiving attention include microstructure/processing/property relationships, clinical failure mechanisms and in vitro testing, wear damage and wear testing, surface treatments, and microstructural modifications. The status of the field is critically reviewed with an eye toward future work. Significant improvements seem possible in the clinical use of ceramics based on engineering solutions derived from the study of clinically failed restorations, on the incorporation of higher levels of "biomimicry" in new systems, and on the synergistic developments in dental cements and adhesive dentin bonding.

  15. Evaluation of marginal fit of two all-ceramic copings with two finish lines

    PubMed Central

    Subasi, Gulce; Ozturk, Nilgun; Inan, Ozgur; Bozogullari, Nalan

    2012-01-01

    Objectives: This in-vitro study investigated the marginal fit of two all-ceramic copings with 2 finish line designs. Methods: Forty machined stainless steel molar die models with two different margin designs (chamfer and rounded shoulder) were prepared. A total of 40 standardized copings were fabricated and divided into 4 groups (n=10 for each finish line-coping material). Coping materials tested were IPS e.max Press and Zirkonzahn; luting agent was Variolink II. Marginal fit was evaluated after cementation with a stereomicroscope (Leica MZ16). Two-way analysis of variance and Tukey-HSD test were performed to assess the influence of each finish line design and ceramic type on the marginal fit of 2 all-ceramic copings (α =.05). Results: Two-way analysis of variance revealed no statistically significant differences for marginal fit relative to finish lines (P=.362) and ceramic types (P=.065). Conclusion: Within the limitations of this study, both types of all-ceramic copings demonstrated that the mean marginal fit was considered acceptable for clinical application (⩽120 μm). PMID:22509119

  16. Effect of various treatment and glazing (coating) techniques on the roughness and wettability of ceramic dental restorative surfaces.

    PubMed

    Aksoy, G; Polat, H; Polat, M; Coskun, G

    2006-12-01

    Surface treatment procedures such as grinding and polishing are needed to provide the ceramic dental restorative materials with proper fitting and occlusion. The treated surfaces are customarily glazed to improve the strength and smoothness. Though smoothness and wetting of the dental surfaces are important to minimize bacterial plaque retention, influence of the surface treatment and glazing procedures on the final surface roughness and its correlation to wettability are overlooked. In this work, effect of various treatment (diamond fraising, stoning, sanding and aluminum oxide and rubber polishing) and glazing (auto and overglazing) techniques on the final roughness and the resulting wettability of dental ceramic surfaces were investigated using scanning electron microscopy (SEM) observations and atomic force microscopy (AFM) scans, 75 scans per sample. The surfaces were characterized and assigned an average roughness measure, R(a). The wettability of the same surfaces was evaluated using micro-contact angle measurements (25 micro-bubbles placed on a grid on each surface) to correlate the final surface roughness and wettability. The results show that overglazing prevails over surface irregularities from different treatment procedures and provides homegeneously smooth surfaces with mean R(a)<10 nm. It also produces uniformly wetted surfaces with low contact angles around 20 degrees . The autoglazed surfaces are less smooth (mean R(a) around 50 nm) and displays sporadic topographic irregularities. They display larger and less uniform contact angles ranging between 35 degrees and 50 degrees . The results suggest that overglazing should be preferred after surface treatment to obtain a smooth and well-wetted dental ceramic surface.

  17. Ensuring the global availability of high-quality dental restorative materials.

    PubMed

    Ferracane, J; Fisher, J; Eiselé, J L; Fox, C H

    2013-11-01

    The Minamata Convention, a global legally binding instrument (treaty) on mercury, has been the catalyst for the emerging agenda on global dental materials research. If the current and future challenges of oral health maintenance and healing on a global scale are to be met, a logical and effective research agenda for the discovery and introduction of new, environmentally sustainable, dental materials must be developed through a coordinated effort involving materials scientists, dental clinicians, representatives of industry, members of regional and national regulatory bodies, and advocacy from research organizations. For universal impact, this agenda should be created with awareness of several important ongoing initiatives, such as the WHO non-communicable diseases action plan, the UN sustainable development agenda, and the IADR Global Oral Health In Inequalities Research Agenda (GOHIRA). A significant contributor to this cause is the FDI and its membership, who, through their Vision 2020 initiative, acknowledge their role and responsibility in globally preventing and managing dental disease and providing leadership to the profession in terms of information dissemination and affecting change. Dental researchers also have an obligation to advocate for appropriate funding to match the identified research needs, thus enhancing the possibility that key decision-makers will provide the needed support to achieve the research agenda agreed upon by this diverse group of stakeholders.

  18. Recommendations for conducting controlled clinical studies of dental restorative materials. Science Committee Project 2/98--FDI World Dental Federation study design (Part I) and criteria for evaluation (Part II) of direct and indirect restorations including onlays and partial crowns.

    PubMed

    Hickel, Reinhard; Roulet, Jean-François; Bayne, Stephen; Heintze, Siegward D; Mjör, Ivar A; Peters, Mathilde; Rousson, Valentin; Randall, Ros; Schmalz, Gottfried; Tyas, Martin; Vanherle, Guido

    2007-01-01

    clinical trial designs, guidelines for design, randomization, number of subjects, characteristics of participants, clinical assessment, standards and calibration, categories for assessment, criteria for evaluation, and supplemental documentation. Part 2 of the review considers categories of assessment for esthetic evaluation, functional assessment, biological responses to restorative materials, and statistical analysis of results. The overall review represents a considerable effort to include a range of clinical research interests over the past years. As part of the recognition of the importance of these suggestions, the review is being published simultaneously in identical form in both the Journal of Adhesive Dentistry and Clinical Oral Investigations. Additionally, an extended abstract will be published in the International Dental Journal, giving a link to the web full version. This should help to introduce these considerations more quickly to the scientific community.

  19. The Efficacy of Noncontingent Escape for Decreasing Children's Disruptive Behavior During Restorative Dental Treatment

    PubMed Central

    O'Callaghan, Patrick M; Allen, Keith D; Powell, Shawn; Salama, Fouad

    2006-01-01

    We evaluated the effectiveness of a dentist-implemented behavioral intervention in which brief escape from dental treatment was provided on a regular basis, independent of the child's behavior. Within a multiple baseline design across subjects, 5 children, ages 4 to 7 years, were provided with temporary escape from dental treatment on a fixed-time schedule. The intervals were signaled by an electronic timer worn by the dentist. Clinically significant reductions were observed in physically disruptive behavior across all 5 children with the introduction of noncontingent escape, and verbally disruptive behavior was markedly reduced in 4 of the 5 children. In addition, the dental staff's use of physical restraint was reduced to near zero across all 5 children. The research extends the literature in both clinical dentistry and in applied behavior analysis by demonstrating that a dentist can easily and effectively implement noncontingent reinforcement to produce clinically significant and socially important changes in children's health behavior. PMID:16813038

  20. Effect of Resin Bonded Luting Agents Influencing Marginal Discrepancy in All Ceramic Complete Veneer Crowns

    PubMed Central

    Sathyamoorthy, Anusha; Ranganathan, Hemalatha; Murthykumar, Karthikeyan

    2016-01-01

    Introduction Marginal discrepancy severely affects the long term success of All ceramic complete veneer crowns. The precise role of resin luting agents influencing this phenomenon needs to be explored further. Aim To estimate and compare the marginal discrepancy in CAD/CAM processed All ceramic complete veneer crowns prior and following luting with resin bonded luting agents. Materials and Methods Extracted human maxillary first premolars were randomly allocated into four groups of 27 samples each Viz., Group I-Resin Modified Glass Ionomer Cement (GIC) (RelyX), Group II-Bis-GMA based dual cure resin cement (Variolink II), Group III-PMMA based resin cement (Superbond), Group IV- Urethane Dimethacrylate resin cement (Calibra). Following tooth preparation, CAD/CAM All ceramic complete veneer crowns were fabricated and sectioned and marginal discrepancy was evaluated using a scanning electron microscope (TESCAN, Magnification power-1,00,000x) prior and after luting with the experimental resin cements. Results The vertical and horizontal discrepancy before and after cementation with Group I [270.08±103.10μm, 165.3±53.00μm and 270.86±102.70μm, 166.62±54.96μm respectively]; Group II [254.21±79.20μm, 117.75±24.29μm and 234.81±79μm, 116.89±18.22μm respectively]; Group III [272.47±86.25μm, 142.08±50.83μm and 251.82±62.69μm, 136.07±44.95μm respectively]; Group IV were [260.28±64.81μm, 116.98±17.71μm and 233.08±69.44μm, 116.58±21.13μm respectively]. ANOVA inferred a statistically significant difference between the four test specimen with regards to vertical and horizontal marginal discrepancy after cementation (F=9.092, p<0.001), (F=10.97, p<0.001). Tukey HSD Post-hoc test observed significant differences in vertical and horizontal marginal discrepancies between the resin modified glass ionomer and resin cements (p<0.05). Conclusion Resin cements exhibited a greater reduction in the marginal discrepancy than the resin modified glass ionomer

  1. Adjunctive role of dental restorations in personal identification of burnt victims

    PubMed Central

    Vandrangi, Sameer Kumar; Radhika, MB; Paremala, K; Reshma, V; Sudhakara, M; Hosthor, Sreelatha S

    2016-01-01

    Background: Fire remains one of the major causes of morbidity and mortality throughout the world and identification of a body from the fatal fire remains a daunting task. Several forensic cases involve interpretation of burnt human bodies from airline and automobile accidents, bombings and unlawful cremation. Fire is also involved in homicides, suicides, accidental death, arson and in attempts to destroy forensic evidence in criminal cases. Soft tissue destruction from fire can be so extensive that conventional methods of identification may be impossible. However, teeth survive even high temperatures due to their resistant composition and so, obviously, the restorative material housed in the teeth are even more secure and can yield valuable information in personal identification. Aim: To assess the usefulness of most common restorations in personal identification in burnt cases. Materials and Methods: The study was conducted on 40 extracted teeth which were divided into four groups (Group 1 - Unrestored teeth, Group 2 - Amalgam restored, Group 3 - Glass ionomer restored and Group 4 - Composite resin restored teeth. The effect of incineration at 200°C, 400°C, 600°C, 800°C, 1000°C for 15 min at each target temperature followed by subsequent cooling was studied. Results: Amalgam restoration was resistant and intact even at 1000°C, whereas GIC and composite restoration are identifiable till 600°C, the residual cavity preparation leaves a clue for narrowing down the spectrum of identification. PMID:27194881

  2. [Adhesion as criterion of choice of materials for dental restorations of defects in cervical area].

    PubMed

    Rusanov, F S; Poiurovskaia, I Ia; Krechina, E K; Sogachev, G V

    2015-01-01

    The paper presents the results of comparative in vitro evaluation of classical and flow consistency restorative polymeric materials (Japan and Russia) adhesion to dentin in cervical area. The adhesive properties of these materials were compared with the experimental systems of "sandwich" type, combining layers of classic and flow consistency, glass-ionomer cement Fuji 8 (Japan) and material SMARTCEM 2 (Switzerland). The highest dentin adhesion strength showed Fuji 8, restoration materials of classical consistency proved to have advantage in adhesion properties.

  3. Measurement of the fluorescence of restorative dental materials using a 655-nm diode laser

    NASA Astrophysics Data System (ADS)

    Zanin, Fatima A. A.; Souza-Campos, Dilma H.; Zanin, Sissi; Brugnera, Aldo, Jr.; Pecora, Jesus D.; Pinheiro, Antonio L. B.; Harari, Sonia

    2001-04-01

    The aim of this study was to determine the level of fluorescence of seven restorative materials using 655 nm diode laser. The laser fluorescence system has ben used as an auxiliary method for the detection of carious lesions. This new diagnostic method increases information which are important for the choice of treatment by the Dentist. The characteristic of restorative materials and sealers interferes in the values obtained by the apparatus during the detection of secondary carious lesions. The optical properties of each biological tissue or material are related to the interaction with the laser beam. Aware of that, the fluorescence of healthy dentin and enamel is 0-15, the authors determined the fluorescence of seven restorative materials with 10 teeth in each group. The laser reading scale differed according to the materia, ranging from 1 to 22 with several materials, for example the sealer without inorganic filler and the glass ionomer, showing fluorescence values similar to carious enamel which interferes with the readings around the restorations resulting in a false positive. Knowledge of restoration material fluorescence can aid in the detection of secondary carious lesions around the restorations.

  4. Knowledge and Awareness among Parents and General Dental Practitioners regarding Rehabilitation with Full Coverage Restoration in Children: A Multi-centric Trial

    PubMed Central

    Saroj, Gyanendra; Sharma, Swati; Gupta, Basant

    2016-01-01

    ABSTRACT Aims: The aim of this study was to evaluate the knowledge and awareness among parents and general dental practitioners regarding rehabilitation with full coverage restoration in children following pulp therapy. Materials and methods: A multiple choice questionnaire was given to 1,000 parents and 400 general practitioners in this multicentric trial. The questionnaire assessed their beliefs, knowledge regarding care of primary teeth, assessment of treating children, and knowledge regarding importance of primary teeth. All the questionnaires were then compiled and statistically analyzed using Statistical Package for Social Sciences (SPSS) software. Results and discussion: 53% parents did not know the importance of primary teeth and 73% parents also thought that no treatment is possible for pulpally involved primary teeth. 20% parents believed that root canal treatment can be possible for children and only 10% knew about full coverage restorations. 40% of the general dentists felt that the best treatment in the case of primary necrotic teeth is extraction and only 13% knew about stainless steel crowns. 62% of general dental practitioners pointed out patients’ noninterest in providing crowns whereas 68% parents reported non-information by dentists. Conclusion: Both parents and general dental practitioners have incomplete and inadequate knowledge regarding full coverage restorations, and we need to improve the knowledge and dental awareness of the parents and the general dental practitioners. How to cite this article: Moda A, Saroj G, Sharma S, Gupta B. Knowledge and Awareness among Parents and General Dental Practitioners regarding Rehabilitation with Full Coverage Restoration in Children: A Multi-centric Trial. Int J Clin Pediatr Dent 2016;9(2):177-180. PMID:27365944

  5. A new approach to influence contact angle and surface free energy of resin-based dental restorative materials.

    PubMed

    Rüttermann, Stefan; Trellenkamp, Taina; Bergmann, Nora; Raab, Wolfgang H-M; Ritter, Helmut; Janda, Ralf

    2011-03-01

    The purpose of the present study was to identify novel delivery systems and active agents which increase the water contact angle and reduce the surface free energy when added to resin-based dental restorative materials. Two delivery systems based on zeolite or novel polymeric hollow beads (Poly-Pore), loaded with two low surface tension active agents (hydroxy functional polydimethylsiloxane and polydimethylsiloxane) or a polymerizable active agent (silicone polyether acrylate) were used to modify commonly formulated experimental dental resin composites. The non-modified resin was used as a standard (ST). Flexural strength, flexural modulus, water sorption, solubility, polymerization shrinkage, surface roughness Ra, contact angle θ, total surface free energy γS, and the apolar γSLW, polar γSAB, Lewis acid γS+ and base γS- components, and the active agents surface tensions γL were determined (P<0.05). The active agents did not differ in γL. The modified materials had significantly higher θ but significantly lower γS, γSAB and γS- than the ST. A Poly-Pore/polydimethyl siloxane delivery system yielded the highest θ (110.9±3.5°) acceptable physical properties and the lowest values for γSLW and γS-. Among the modified materials the polymerizable materials containing active agents had the lowest γAB and the highest γS+ and γS-. Although not significant, both of the zeolite delivery systems yielded higher γSLW, γS+ and γS- but lower γSAB than the Poly-Pore delivery systems. Poly-Pore based delivery systems highly loaded with low surface tension active agents were found not to influence the physical properties but to significantly increase the water contact angle and thus reduce surface free energy of dental resin composites.

  6. "Struggle to obtain redress": Women's experiences of living with symptoms attributed to dental restorative materials and/or electromagnetic fields.

    PubMed

    Mårell, Lena; Lindgren, Monica; Nyhlin, Kerstin Ternulf; Ahlgren, Christina; Berglund, Anders

    2016-01-01

    The aim of this study was to explore the experiences of illness and the encounters with health care professionals among women who attributed their symptoms and illness to either dental restorative materials and/or electromagnetic fields, despite the fact that research on health effects from dental fillings or electricity has failed to substantiate the reported symptoms. Thirteen women (aged 37-63 years) were invited to the study and a qualitative approach was chosen as the study design, and data were collected using semi-structured interviews. The analysis was conducted with a constant comparative method, according to Grounded Theory. The analysis of the results can be described with the core category, "Struggle to obtain redress," the two categories, "Stricken with illness" and "A blot in the protocol," and five subcategories. The core category represents the women's fight for approval and arose in the conflict between their experience of developing a severe illness and the doctors' or dentists' rejection of the symptoms as a disease, which made the women feel like malingerers. The informants experienced better support and confirmation from alternative medicine practitioners. However, sick-leave certificates from alternative medicine practitioners were not approved and this led to a continuous cycle of visits in the health care system. To avoid conflicting encounters, it is important for caregivers to listen to the patient's explanatory models and experience of illness, even if a medical answer cannot be given.

  7. The chewing robot: a new biologically-inspired way to evaluate dental restorative materials.

    PubMed

    Raabe, D; Alemzadeh, K; Harrison, A L; Ireland, A J

    2009-01-01

    This paper presents a novel in vitro dental wear simulator based on 6-6 parallel kinematics to replicate mechanical wear formation on dental materials and components, such as individual teeth, crowns or bridges. The human mandible, guided by a range of passive structures moves with up to six degrees of freedom (DOF). Currently available wear simulators lack the ability to perform these complex chewing movements. In addition simulators are unable to replicate the normal range of chewing forces as they have no control system able to mimic the natural muscle function controlled by the human central nervous system. Such discrepancies between true in vivo and simulated in vitro movements will influence the outcome and reliability of wear studies using such approaches. This paper summarizes the development of a new dynamic jaw simulator based on the kinematics of the human jaw.

  8. Fracture load of implant-supported zirconia all-ceramic crowns luted with various cements.

    PubMed

    Lim, Hyun-Pil; Yoo, Jeong-Min; Park, Sang-Won; Yang, Hong-So

    2010-01-01

    This study compared the fracture load and failure types of implant-supported zirconia all-ceramic crowns cemented with various luting agents. The ceramic frameworks were fabricated from a presintered yttria-stabilized zirconium dioxide block using computer-aided design/computer-assisted manufacturing technology, and were then veneered with feldspathic porcelain. Three luting agents were used. Composite resin cement (1,560.78 +/- 39.43 N) showed the highest mean fracture load, followed by acrylic/urethane cement (1,116.20 +/- 77.32 N) and zinc oxide eugenol cement (741.21 +/- 41.95 N) (P < .05). The types of failure varied between groups.

  9. Comparison of 3 polishing techniques for 2 all-ceramic materials.

    PubMed

    Saraç, Duygu; Turk, Tamer; Elekdag-Turk, Selma; Saraç, Y Sinaç

    2007-01-01

    The aim of this study was to compare the surface roughness produced by polishing 2 all-ceramic materials after surface conditioning. Air particle abrasion (APA) with 25-microm aluminum oxide, 9.6% hydrofluoric acid (HFA,) and APA + HFA were applied for ceramic surface conditioning. Subsequently, the ceramics were subjected to 3 polishing techniques: polishing kit, polishing paste, and polishing kit + polishing paste. Surface roughness (Ra) was evaluated profilometrically. The highest deltaRa values were obtained with the polishing kit and polishing kit + paste for the APA + HFA groups. No significant differences were observed among the polishing paste groups. Combining a polishing kit and polishing paste produced the smoothest ceramic surfaces.

  10. Ester-free Thiol-ene Dental Restoratives – Part A: Resin Development

    PubMed Central

    Podgórski, Maciej; Becka, Eftalda; Claudino, Mauro; Flores, Alexander; Shah, Parag K.; Stansbury, Jeffrey W.; Bowman, Christopher N.

    2015-01-01

    Objectives To detail the development of ester-free thiol-ene dental resins with enhanced mechanical performance, limited potential for water uptake/leachables/degradation and low polymerization shrinkage stress. Methods Thiol-terminated oligomers were prepared via a thiol-Michael reaction and a bulky tetra-allyl monomer containing urethane linkages was synthesized. The experimental oligomers and/or monomers were photopolymerized using visible light activation. Several thiol-ene formulations were investigated and their performance ranked by comparisons of the thermo-mechanical properties, polymerization shrinkage stress, water sorption/solubility, and reactivity with respect to a control comprising a conventional BisGMA/TEGDMA dental resin. Results The ester-free thiol-ene formulations had significantly lower viscosities, water sorption and solubility than the BisGMA/TEGDMA control. Depending on the resin, the limiting functional conversions were equivalent to or greater than that of BisGMA/TEGDMA. At comparable conversions, lower shrinkage stress values were achieved by the thiol-ene systems. The polymerization shrinkage stress was dramatically reduced when the tetra-allyl monomer was used as the ene in ester-free thiol-ene mixtures. Although exhibiting lower Young’s modulus, flexural strength, and glass transition temperatures, the toughness values associated with thiol-ene resins were greater than that of the BisGMA/TEGDMA control. In addition, the thiol-ene polymerization resulted in highly uniform polymer networks as indicated by the narrow tan delta peak widths. Significance Employing the developed thiol-ene resins in dental composites will reduce shrinkage stress and moisture absorption and form tougher materials. Furthermore, their low viscosities are expected to enable higher loadings of functionalized micro/nano-scale filler particles relevant for practical dental systems. PMID:26360013

  11. Recent advances in dental optics - Part I: 3D intraoral scanners for restorative dentistry

    NASA Astrophysics Data System (ADS)

    Logozzo, Silvia; Zanetti, Elisabetta M.; Franceschini, Giordano; Kilpelä, Ari; Mäkynen, Anssi

    2014-03-01

    Intra-oral scanning technology is a very fast-growing field in dentistry since it responds to the need of an accurate three-dimensional mapping of the mouth, as required in a large number of procedures such as restorative dentistry and orthodontics. Nowadays, more than 10 intra-oral scanning devices for restorative dentistry have been developed all over the world even if only some of those devices are currently available on the market. All the existing intraoral scanners try to face with problems and disadvantages of traditional impression fabrication process and are based on different non-contact optical technologies and principles. The aim of this publication is to provide an extensive review of existing intraoral scanners for restorative dentistry evaluating their working principles, features and performances.

  12. The Use of Micro-CT with Image Segmentation to Quantify Leakage in Dental Restorations

    PubMed Central

    Carrera, Carola A.; Lan, Caixia; Escobar-Sanabria, David; Li, Yuping; Rudney, Joel; Aparicio, Conrado; Fok, Alex

    2015-01-01

    Objective To develop a method for quantifying leakage in composite resin restorations after curing, using non-destructive X-ray micro-computed tomography (micro-CT) and image segmentation. Methods Class-I cavity preparations were made in 20 human third molars, which were divided into 2 groups. Group I was restored with Z100 and Group II with Filtek LS. Micro-CT scans were taken for both groups before and after they were submerged in silver nitrate solution (AgNO3 50%) to reveal any interfacial gap and leakage at the tooth restoration interface. Image segmentation was carried out by first performing image correlation to align the before- and after-treatment images and then by image subtraction to isolate the silver nitrate penetrant for precise volume calculation. Two-tailed Student’s t-test was used to analyze the results, with the level of significance set at p<0.05. Results All samples from Group I showed silver nitrate penetration with a mean volume of 1.3 ± 0.7 mm3. In Group II, only 2 out of the 10 restorations displayed infiltration along the interface, giving a mean volume of 0.3 ± 0.3 mm3. The difference between the two groups was statistically significant (p < 0.05). The infiltration showed non-uniform patterns within the interface. Significance We have developed a method to quantify the volume of leakage using non-destructive micro-CT, silver nitrate infiltration and image segmentation. Our results confirmed that substantial leakage could occur in composite restorations that have imperfections in the adhesive layer or interfacial debonding through polymerization shrinkage. For the restorative systems investigated in this study, this occurred mostly at the interface between the adhesive system and the tooth structure. PMID:25649496

  13. [Atraumatic restorative treatment: a dental alternative well-received by children].

    PubMed

    Aguirre Aguilar, Antonio Armando; Rios Caro, Teresa Etelvina; Huamán Saavedra, Jorge; França, Cristiane Miranda; Fernandes, Kristianne Porta Santos; Mesquita-Ferrari, Raquel Agnelli; Bussadori, Sandra Kalil

    2012-02-01

    The purpose of this study is to compare atraumatic restorative treatment (ART) with the conventional rotational restorative method (CM) to determine in both cases the total time required for the procedure, the cost, the presence of pain, and the behavior of pediatric patients in Peru. Of the 30 children selected for the study, half received ART and restoration with glass ionomer cement and the other half, CM and restoration with amalgam. The study parameters were the times required to remove the decayed tissue and to complete the entire procedure, the total cost of the procedure, the presence of pain, and the patient's behavior during treatment. Significant differences were found between the two techniques in all parameters, except for the patient's behavior. Although removing the decayed tissue was faster with the CM, the entire procedure was faster with ART, which, moreover, was significantly less expensive and less painful than the CM. The results indicated that ART is a very good alternative due to its low cost and acceptance by the children.

  14. Clinical cross-polarization optical coherence tomography assessment of subsurface enamel below dental resin composite restorations

    PubMed Central

    Lenton, Patricia; Rudney, Joel; Fok, Alex; Jones, Robert S.

    2014-01-01

    Abstract. A newly designed intraoral swept source cross-polarization optical coherence tomography (CP-OCT) imaging system was used to examine the integrity of the subsurface enamel below resin composite restorations placed in primary teeth. CP-OCT analysis was performed using images obtained from resin composite restoration in 62 (n=62) pediatric subjects. Clinical examination was performed by a single examiner prior to CP-OCT imaging and analysis. CP-OCT images are presented using a unique combined intensity image, where a false color scale is overlaid on the grayscale intensity image. There was a clear difference in the distribution of the mean-backscattered intensity (mR) between restorations recently placed and those possessing frank cavitation (Student’s t-test, P<0.0001). For mR above 15.49 dB, the sensitivity was 80% and specificity 86%. The Youden index J was 0.8 above 12.3 dB where sensitivity was 100% and specificity was 80%. CP-OCT imaging may be used to confirm the subsurface marginal integrity below resin composite restorations but with careful consideration of limitations of the imaging modality. CP-OCT imaging may be a useful adjunct to clinical visual investigation to confirm that a composite margin has a sound and well-adapted interface. PMID:26158031

  15. Comparison of the translucency of shaded zirconia all-ceramic systems

    PubMed Central

    Ulusoy, Mutahhar

    2014-01-01

    PURPOSE The purpose of this study was to evaluate and compare the translucency of shaded zirconia all-ceramic systems. MATERIALS AND METHODS Translucency of 3 different zirconia all-ceramic systems colored by different techniques was compared with a lithium disilicate glass-ceramic (IPS e.max Press). Square-shaped specimens with 0.5 mm thickness were fabricated from In-Ceram YZ, ICE Zirkon and Katana systems in A1, A2 and A3.5 shades according to Vitapan Classical shade tab (n=11). Specimens were then veneered and glazed with corresponding veneer ceramic recommended by each zirconia system manufacturer and the total thickness was set to 1.5 mm. Translucency measurements were performed with VITA Easyshade Compact spectrophotometer after each stage and translucency parameter was calculated. Data were statistically analyzed with repeated measures ANOVA and Tukey multiple comparison test. RESULTS The control group was significantly more translucent than the zirconia systems (P<.05). ICE Zirkon cores showed the least translucency; neither In-Ceram YZ nor Katana systems were superior to each other in terms of translucency. Translucency of all specimens was decreased after veneering, and the translucency rankings were changed. CONCLUSION Coloring technique did not have a significant effect on translucency of zirconia cores. Although zirconia systems were less translucent than lithium disilicate glass ceramic, they had partial translucency and there were translucency differences among the zirconia systems. Chroma affected the translucency of precolored zirconia cores. PMID:25352964

  16. Impact of Technique-Specific Operative Videos on First-Year Dental Students' Performance of Restorative Procedures.

    PubMed

    Patel, Shalizeh A; Barros, Juliana A; Clark, Christina M; Frey, Gary N; Streckfus, Charles F; Quock, Ryan L

    2015-09-01

    The aim of this study was to examine the impact of psychomotor operative video demonstrations on first-year dental students who are performing specific procedures for the first time in a preclinical setting. The class was randomly divided into two groups, and three restorative procedures were selected. On the date on which each procedure was to be performed in the preclinical laboratory for the first time, one group (experimental, n=50) was shown a technique video for that specific procedure immediately before commencing the exercise; the control cohort (n=50) did not view the video. Technical performance on procedures was evaluated by students and two calibrated and blinded examiners. The students' perceptions of the experience were also collected in a survey. All first-year students participated in the study, for a 100% response rate. A Mann-Whitney U test did not show any group differences in technical performance (mean values on preparation: 77.1 vs. 77.8; amalgam: 82.7 vs. 82.8; composite: 79.7 vs. 78.0). A Spearman rho test revealed a significantly higher correlation in 13 out of 25 evaluation categories between student self-assessment and blinded examiner assessment for the experimental group. A chi-square test of questionnaire responses revealed a positive student perception of administering these videos for the preparation (X(2)=4.8, p<0.03), the amalgam restoration (X(2)=12.4, p<0.001), and the composite restoration (X(2)=11.3, p<0.001). The psychomotor video demonstrations did not immediately improve student performance on preclinical operative procedures, but they were well received by students and augmented self-assessment ability. These findings suggest that videos can be a useful teaching aid in a preclinical environment, especially regarding comprehension of concepts.

  17. Evaluation of an experimental Ti-Co alloy for dental restorations.

    PubMed

    Wang, Russell; Welsch, Gerhard

    2013-11-01

    Precision and surface quality of pure titanium (Ti) castings for dental and biomedical uses are limited because of the high melting temperature and the violent reactivity of Ti with mold materials during casting procedures. This feasibility study evaluates an experimental low-melting Ti-Co alloy in term of its microstructure and physical and mechanical properties. Tensile samples of Ti-12 wt % Co alloy were cast under a protective argon atmosphere. The melting range of the cast samplers was determined. Cast samples were annealed at 1010°C for various time intervals in order to homogenize microstructures. Microstructures were examined by optical and scanning electron microscopy. Tensile strength and microhardness tests were performed and correlated with microstructures resulting from annealing processes. Ti2Co intermetallic compound coexisted with Ti-Co solid solution in all samples. The melting range of the alloy was 1062-1088°C, which is 568°C lower than that of Ti. The thickness of the surface oxide scale on cast samples was dramatically reduced to 1-3 μm because of the low-melting nature of the alloy. Solution treatment at 1010°C for 100 h yields the highest tensile strength. Ultimate tensile strength is measured from 852 to 1240 MPa which is stronger than currently used dental alloys. Microhardness values were ranged from 341 to 488 KHN and elongation was from 1.2 to 1.8%. Both microhardness and percentage elongation are similar to those of dental Co-Cr alloys. One hundred hours of annealing dissolved dendritic boundaries and transformed the alloy to a more microductitle matrix, however, the intermetallic compound of Ti2Co remained.

  18. Rapid and non-destructive analysis of metallic dental restorations using X-ray fluorescence spectra and light-element sampling tools

    NASA Astrophysics Data System (ADS)

    Furuhashi, K.; Uo, M.; Kitagawa, Y.; Watari, F.

    2012-12-01

    IntroductionRecently, allergic diseases caused by dental metals have been increasing. Therefore, rapid and accurate analytical methods for the metal restorations in the oral cavities of patients are required. The purpose of this study was to develop a non-destructive extraction method for dental alloys, along with a subsequent, rapid and accurate elemental analysis. Materials and methodSamples were obtained by polishing the surfaces of metal restorations using a dental rotating tool with disposable buffs and polishing pastes. As materials for the analysis, three dental alloys were used. To compare the sampling and analysis efficiencies, two buffs and seven pastes were used. After polishing the surface of a metal restoration, the buff was analyzed using X-ray scanning analytical microscopy (XSAM). ResultsThe efficiency of the analysis was judged based on the sampling rate achieved and the absence of disturbing elements in the background in fluorescence X-ray spectra. The best results were obtained for the combination of TexMet as a buff with diamond as a paste. This combination produced a good collection efficiency and a plain background in the fluorescence X-ray spectra, resulting in a high precision of the analysis.

  19. Comparison of acceptance, preference and efficacy between pressure anesthesia and classical needle infiltration anesthesia for dental restorative procedures in adult patients

    PubMed Central

    Makade, Chetana Sachin; Shenoi, Pratima R; Gunwal, Mohit K

    2014-01-01

    Introduction: Intraoral local anesthesia is essential for delivering dental care. Needless devices have been developed to provide anesthesia without injections. Little controlled research is available on its use in dental restorative procedures in adult patients. The aims of this study were to compare adult patients acceptability and preference for needleless jet injection with classical local infiltration as well as to evaluate the efficacy of the needleless anesthesia. Materials and Methods: Twenty non fearful adults with no previous experience of dental anesthesia were studied using split-mouth design. The first procedure was performed with classical needle infiltration anesthesia. The same amount of anesthetic solution was administered using MADA jet needleless device in a second session one week later, during which a second dental restorative procedure was performed. Patients acceptance was assessed using Universal pain assessment tool while effectiveness was recorded using soft tissue anesthesia and pulpal anesthesia. Patients reported their preference for the anesthetic method at the third visit. The data was evaluated using chi square test and student's t-test. Results: Pressure anesthesia was more accepted and preferred by 70% of the patients than traditional needle anesthesia (20%). Both needle and pressure anesthesia was equally effective for carrying out the dental procedures. Conclusion: Patients experienced significantly less pain and fear (p<0.01) during anesthetic procedure with pressure anesthesia. However, for more invasive procedures needle anesthesia will be more effective. PMID:24778516

  20. R-curve behavior and micromechanisms of fracture in resin based dental restorative composites.

    PubMed

    Shah, M B; Ferracane, J L; Kruzic, J J

    2009-10-01

    The fracture properties and micromechanisms of fracture for two commercial dental composites, one microhybrid (FiltekZ250) and one nanofill (FiltekSupreme Plus), were studied by measuring fracture resistance curves (R-curves) using pre-cracked compact-tension specimens and by conducting both unnotched and double notched four point beam bending experiments. Four point bending experiments showed about 20% higher mean flexural strength of the microhybrid composite compared to the nanofill. Rising fracture resistance was observed over approximately 1 mm of crack extension for both composites, and higher overall fracture resistance was observed for the microhybrid composite. Such fracture behavior was attributed to crack deflection and crack bridging toughening mechanisms that developed with crack extension, causing the toughness to increase. Despite the lower strength and toughness of the present nanofill composite, based on micromechanics observations, large nanoparticle clusters appear to be as effective at deflecting cracks and imparting toughening as solid particles. Thus, with further microstructural refinement, it should be possible to achieve a superior combination of aesthetic and mechanical performance using the nanocluster approach for dental composites.

  1. Fracture Toughness of Veneering Ceramics for Fused to Metal (PFM) and Zirconia Dental Restorative Materials

    PubMed Central

    Quinn, Janet B.; Quinn, George D.; Sundar, Veeraraghaven

    2010-01-01

    Veneering ceramics designed to be used with modern zirconia framework restorations have been reported to fracture occasionally in vivo. The fracture toughness of such veneering ceramics was measured and compared to that of conventional feldspathic porcelain veneering ceramics for metal framework restorations. The fracture toughness of the leucite free veneer was measured to be 0.73 MPa m ± 0.02 MPa m, which is less than that for the porcelain fused to metal (PFM) veneering ceramic: 1.10 MPa ± 0.2 MPa. (Uncertainties are one standard deviation unless otherwise noted.) The surface crack in flexure (SCF) method was suitable for both materials, but precrack identification was difficult for the leucite containing feldspathic porcelain PFM veneer. PMID:21833158

  2. A 24-month Evaluation of Amalgam and Resin-Based Composite Restorations: Findings from The National Dental Practice-Based Research Network

    PubMed Central

    McCracken, Michael S.; Gordan, Valeria V.; Litaker, Mark S.; Funkhouser, Ellen; Fellows, Jeffrey L.; Shamp, Douglass G.; Qvist, Vibeke; Meral, Jeffrey S.; Gilbert, Gregg H.

    2013-01-01

    Background Knowing which factors influence restoration longevity can help clinicians make sound treatment decisions. The authors analyzed data from the National Dental Practice-Based Research Network to identify predictors of early failures of amalgam and resin-based composite (RBC) restorations. Methods This prospective cohort study gathered information from clinicians and offices participating in the network. Clinicians completed a baseline data collection form at the time of restoration placement, and annually thereafter. Data collected included patient factors, practice factors, and dentist factors, and were analyzed using mixed-model logistic regression. Results A total of 226 practitioners followed 6,218 direct restorations in 3,855 patients; 386 restorations failed (6.6 percent) during the mean follow-up period of 23.7 (SD 8.8) months. The number of tooth surfaces restored at baseline predicted subsequent restoration failure; large restorations were over 4 times more likely to fail. Material was not significantly associated with longevity; neither was tooth type. Patient age was highly associated with failure (p<0.0001). The failure rate for children was 5 percent, compared to 12 percent in persons 65 years old or older. Dentist gender and practice workload were significantly associated with restoration longevity. Conclusions In this prospective cohort study, these factors significantly predicted an increased failure rate for amalgam and RBC restorations: older patient age and a higher number of surfaces restored at baseline, with other key baseline variables taken into account. Material choice was not significantly predictive in these early results. Clinical Implications Understanding risk factors for early restoration failure may lead to more-effective patient care. PMID:23729455

  3. Thickness of immediate dentin sealing materials and its effect on the fracture load of a reinforced all-ceramic crown

    PubMed Central

    Spohr, Ana Maria; Borges, Gilberto Antonio; Platt, Jeffrey A.

    2013-01-01

    Objectives: The objective of this study is to evaluate, in vitro, the thickness of immediate dentin sealing (IDS) materials on full crown preparations and its effect on the fracture load of a reinforced all-ceramic crown. Materials and Methods: Sixty premolars received full crown preparation and were divided into the following groups according to the IDS technique: G1-control; G2-Clearfil SE Bond; and G3-Clearfil SE Bond and Protect Liner F. After the impressions were taken, the preparations were temporized with acrylic resin crowns. IPS empress 2 restorations were fabricated and later cemented on the preparations with Panavia F. 10 specimens from each group were submitted to fracture load testing. The other 10 specimens were sectioned buccolingually before the thicknesses of Panavia F, Clearfil SE Bond and Protect Liner F were measured in 10 different positions using a microscope. Results: According to analysis of variance and Tukey's test, the fracture load of Group 3 (1300 N) was significantly higher than that of Group 1 (1001 N) (P < 0.01). Group 2 (1189 N) was not significantly different from Groups 1 and 3. The higher thickness of Clearfil SE Bond was obtained in the concave part of the preparation. Protect Liner F presented a more uniform range of values at different positions. The thickness of Panavia F was higher in the occlusal portion of the preparation. Conclusions: The film thickness formed by the IDS materials is influenced by the position under the crown, suggesting its potential to increase the fracture load of the IPS empress 2 ceramic crowns. PMID:24932124

  4. Open photoacoustic cell for thermal diffusivity measurements of a fast hardening cement used in dental restoring

    NASA Astrophysics Data System (ADS)

    Astrath, F. B. G.; Astrath, N. G. C.; Baesso, M. L.; Bento, A. C.; Moraes, J. C. S.; Santos, A. D.

    2012-01-01

    Thermal diffusivity and conductivity of dental cements have been studied using open photoacoustic cell (OPC). The samples consisted of fast hardening cement named CER, developed to be a root-end filling material. Thermal characterization was performed in samples with different gel/powder ratio and particle sizes and the results were compared to the ones from commercial cements. Complementary measurements of specific heat and mass density were also performed. The results showed that the thermal diffusivity of CER tends to increase smoothly with gel volume and rapidly against particle size. This behavior was linked to the pores size and their distribution in the samples. The OPC method was shown to be a valuable way in deriving thermal properties of porous material.

  5. FDI World Dental Federation - clinical criteria for the evaluation of direct and indirect restorations. Update and clinical examples.

    PubMed

    Hickel, Reinhard; Peschke, Arnd; Tyas, Martin; Mjör, Ivar; Bayne, Stephen; Peters, Mathilde; Hiller, Karl-Anton; Randall, Ross; Vanherle, Guido; Heintze, Siegward D

    2010-08-01

    In 2007, new clinical criteria were approved by the FDI World Dental Federation and simultaneously published in three dental journals. The criteria were categorized into three groups: esthetic parameters (four criteria), functional parameters (six criteria), and biological parameters (six criteria). Each criterion can be expressed with five scores, three for acceptable and two for non-acceptable (one for reparable and one for replacement). The criteria have been used in several clinical studies since 2007, and the resulting experience in their application has led to a requirement to modify some of the criteria and scores. The two major alterations involve staining and approximal contacts. As staining of the margins and the surface have different causes, both phenomena do not appear simultaneously. Thus, staining has been differentiated into marginal staining and surface staining. The approximal contact now appears under the name "approximal anatomic form" as the approximal contour is a specific, often non-esthetic issue that cannot be integrated into the criterion "esthetic anatomical form". In 2008, a web-based training and calibration tool called e-calib (www.e-calib.info) was made available. Clinical investigators and other research workers can train and calibrate themselves interactively by assessing clinical cases of posterior restorations, which are presented as high quality pictures. Currently, about 300 clinical cases are included in the database which is regularly updated. Training for 8 of the 16 clinical criteria is available in the program: "Surface luster"; "Staining (surface, margins)"; "Color match and translucency"; "Esthetic anatomical form"; "Fracture of material and retention"; "Marginal adaptation"; "Recurrence of caries, erosion, abfraction"; and "Tooth integrity (enamel cracks, tooth fractures)". Typical clinical cases are presented for each of these eight criteria and their corresponding five scores.

  6. FDI World Dental Federation: clinical criteria for the evaluation of direct and indirect restorations-update and clinical examples.

    PubMed

    Hickel, Reinhard; Peschke, Arnd; Tyas, Martin; Mjör, Ivar; Bayne, Stephen; Peters, Mathilde; Hiller, Karl-Anton; Randall, Ross; Vanherle, Guido; Heintze, Siegward D

    2010-08-01

    In 2007, new clinical criteria were approved by the FDI World Dental Federation and simultaneously published in three dental journals. The criteria were categorized into three groups: esthetic parameters (four criteria), functional parameters (six criteria) and biological parameters (six criteria). Each criterion can be expressed with five scores, three for acceptable and two for non-acceptable (one for reparable and one for replacement). The criteria have been used in several clinical studies since 2007, and the resulting experience in their application has led to a requirement to modify some of the criteria and scores. The two major alterations involve staining and approximal contacts. As staining of the margins and the surface has different causes, both phenomena do not appear simultaneously. Thus, staining has been differentiated into marginal staining and surface staining. The approximal contact now appears under the name "approximal anatomic form" as the approximal contour is a specific, often non-esthetic issue that cannot be integrated into the criterion "esthetic anatomical form". In 2008, a web-based training and calibration tool called e-calib ( www.e-calib.info ) was made available. Clinical investigators and other research workers can train and calibrate themselves interactively by assessing clinical cases of posterior restorations which are presented as high-quality pictures. Currently, about 300 clinical cases are included in the database which is regularly updated. Training for eight of the 16 clinical criteria is available in the program: "Surface lustre"; "Staining (surface, margins)"; "Color match and translucency"; Esthetic anatomical form"; "Fracture of material and retention"; "Marginal adaptation"; "Recurrence of caries, erosion, abfraction"; and "Tooth integrity (enamel cracks, tooth fractures)". Typical clinical cases are presented for each of these eight criteria and their corresponding five scores.

  7. Veneer vs. core failure in adhesively bonded all-ceramic crown layers.

    PubMed

    Lee, J J-W; Kwon, J-Y; Bhowmick, S; Lloyd, I K; Rekow, E D; Lawn, B R

    2008-04-01

    Joining a brittle veneer to a strong ceramic core with an adhesive offers potential benefits over current fabrication methods for all-ceramic crowns. We tested the hypothesis that such joining can withstand subsurface radial cracking in the veneer, from enhanced flexure in occlusal loading, as well as in the core. Critical conditions to initiate fractures were investigated in model crown-like layer structures consisting of glass veneers epoxy-joined onto alumina or zirconia cores, all bonded to a dentin-like polymer base. The results showed a competition between critical loads for radial crack initiation in the veneers and cores. Core radial cracking was relatively independent of adhesive thickness. Zirconia cores were much less susceptible to fracture than alumina, attributable to a relatively high strength and low modulus. Veneer cracking did depend on adhesive thickness. However, no significant differences in critical loads for veneer cracking were observed for specimens containing alumina or zirconia cores.

  8. Tissue management and retraction technique combined with all-ceramic crowns: case reports.

    PubMed

    Ferrari, M; Nathanson, D

    1995-04-01

    The need to preserve the gingival health during impression making for laboratory fabricated prostheses has been emphasized in literature and clinical practice. This article presents the placement of all-ceramic crowns utilizing a relatively new soft tissue retraction material, a polymer, cut into 2 mm wide strips. The sponge-like texture of the material expands with moisture and exerts gentle pressure on the gingival tissue, effecting a retraction for impressions. The gingival tissue returns to its original position within 24 hours. The learning objective of this article is to share the experience and observations of this procedure and the materials utilized. Several case reports are presented to illustrate the clinical procedure and the results obtained.

  9. Two-piece zirconia implants supporting all-ceramic crowns: A prospective clinical study

    PubMed Central

    Cionca, Norbert; Müller, Nada; Mombelli, Andrea

    2015-01-01

    Objectives The aim of this prospective clinical study is to evaluate the safety and efficacy of a new all-ceramic implant system to replace missing teeth in partially edentulous patients. Material and methods Thirty-two partially edentulous, systemically healthy patients were treated with 49 two-piece zirconia implants (ZERAMEX® T Implant System). Zirconia abutments were connected with adhesive resin cement. Single-unit full-ceramic crowns were cemented. The cases have been followed for 588±174 days after loading (range 369–889 days). All patients have been re-evaluated 1 year after loading. Results The cumulative survival rate 1 year after loading was 87% implants. All failures were the result of aseptic loosening, and no implants were lost after the first year. The results of the other cases were good, and the patients were very satisfied. The cumulative soft tissue complication rate was 0%, the cumulative technical complication rate was 4% implants, the cumulative complication rate for bone loss >2 mm was 0%, and the cumulative esthetic complication rate was 0%. Including the data from 20 patients treated with an earlier version of the system, an over-all 2-year cumulative survival rate of 86% was calculated for a total of 76 two-piece zirconia implants supporting all-ceramic crowns in 52 patients. Conclusions Replacement of single teeth in the posterior area was possible with this new full-ceramic implant system. Failures were due to aseptic loosening. PMID:24666352

  10. MARGINAL ADAPTATION AND PERFORMANCE OF BIOACTIVE DENTAL RESTORATIVE MATERIALS IN DECIDUOUS AND YOUNG PERMANENT TEETH

    PubMed Central

    Gjorgievska, Elizabeta; Nicholson, John W.; Iljovska, Snezana; Slipper, Ian J.

    2008-01-01

    Objective: The aim of this study was to investigate the adaptation of different types of restorations towards deciduous and young permanent teeth. Materials and Methods: Class V cavities were prepared in deciduous and young permanent teeth and filled with different materials (a conventional glass-ionomer, a resin-modified glass-ionomer, a poly-acid-modified composite resin and a conventional composite resin). Specimens were aged in artificial saliva for 1, 6, 12 and 18 months, then examined by SEM. Results: The composite resin and the polyacid-modified composite had better marginal adaptation than the glass-ionomers, though microcracks developed in the enamel of the tooth. The glass-ionomers showed inferior marginal quality and durability, but no microcracking of the enamel. The margins of the resin-modified glass-ionomer were slightly superior to the conventional glass-ionomer. Conditioning improved the adaptation of the composite resin, but the type of tooth made little or no difference to the performance of the restorative material. All materials were associated with the formation of crystals in the gaps between the filling and the tooth; the quantity and shape of these crystals varied with the material. Conclusions: Resin-based materials are generally better at forming sound, durable margins in deciduous and young permanent teeth than cements, but are associated with microcracks in the enamel. All fluoride-releasing materials give rise to crystalline deposits. PMID:19089281

  11. The assessment of surface roughness and microleakage of eroded tooth-colored dental restorative materials

    PubMed Central

    Hussein, Thulfiqar Ali; Bakar, Wan Zaripah Wan; Ghani, Zuryati Ab; Mohamad, Dasmawati

    2014-01-01

    Objectives: To investigate the effect of acidic solution on surface roughness and microleakage of tooth-colored restorative materials. Materials and Methods: A 160 box-shaped cavities were prepared on the buccal surfaces of 160 human molars, and assigned to four groups: Group A restored with Ketac™ Molar Easymix, Group B with Fuji II™ LC, Group C with Ketac™ N100, and Group D with Filtek™ Z250, and subdivided into study and control groups (n = 20). Study groups were immersed in lemon juice (pH = 2.79) for 24 h, whilst controlgroups in deionized distilled water. All samples were immersed in 2% methylene blue dye, sectioned into two equal halves for surface roughness, and microleakage tests. Data were analyzed using Mann–Whitney and Kruskal–Wallis tests at P < 0.05. Results: There was a significant difference in surface roughness of Ketac™ Molar, Fuji II™ LC, and Ketac™ N100. No significant difference was found in microleakage of Ketac™ Molar and Fuji II™ LC; however, there were significant differences in the gingival margin of Ketac™ N100, and the occlusal margin of Filtek™ Z250. Conclusions: All glass ionomer cements were eroded after exposure to the acidic drink. Filtek™ Z250 and Ketac™ Molar Easymix showed more microleakage. All materials showed more microleakage at the gingival margins. PMID:25506139

  12. Dental OCT

    NASA Astrophysics Data System (ADS)

    Colston, Bill W.; Sathyam, Ujwal S.; Dasilva, Luiz B.; Everett, Matthew J.; Stroeve, Pieter; Otis, L. L.

    1998-09-01

    We present here the first in vivo optical coherence tomography (OCT) images of human dental tissue. A novel dental optical coherence tomography system has been developed. This system incorporates the interferometer sample arm and transverse scanning optics into a handpiece that can be used intraorally to image human dental tissues. The average imaging depth of this system varied from 3 mm in hard tissues to 1.5 mm in soft tissues. We discuss the application of this imaging system for dentistry and illustrate the potential of our dental OCT system for diagnosis of periodontal disease, detection of caries, and evaluation of dental restorations.

  13. Fracture and shear bond strength analyses of different dental veneering ceramics to zirconia.

    PubMed

    Diniz, Alexandre C; Nascimento, Rubens M; Souza, Julio C M; Henriques, Bruno B; Carreiro, Adriana F P

    2014-05-01

    The purpose of this work was to evaluate the interaction of different layering porcelains with zirconia via shear bond strength test and microscopy. Four different groups of dental veneering porcelains (VM9, Zirkonzanh, Ceramco, IPS) were fused onto forty zirconia-based cylindrical substrates (8mm in diameter and 12 mm in height) (n=10), according to the manufacturer's recommendations. Additionally, layered dental porcelain (D-sign, Ivoclar) was fired on ten Ni-Cr cylindrical substrates Shear bond strength tests of the veneering porcelain to zirconia or Ni-Cr were carried out at a crosshead speed of 0.5mm/min. After the shear bond tests, the interfaces were analyzed by scanning electron microscopy (SEM). The fracture type exhibited by the different systems was also assessed. The results were statistically analyzed by ANOVA at a significant level of p<.05. The shear bond strength values of the porcelain-to-NiCr interfaces (25.3±7.1 MPa) were significantly higher than those recorded for the following porcelain-to-zirconia systems: Zirkonzanh (18.8±1 MPa), Ceramco (18.2±4.7 MPa), and IPS (16±4.5 MPa). However, no significant differences were found in the shear bond strength values between the porcelain-to-NiCr and porcelain (VM9)-to-zirconia (23.2±5.1 MPa) groups (p>.05). All-ceramic interfaces revealed mixed failure type, cohesive in the porcelain and adhesive at the interface. This study demonstrated that all-ceramic systems do not attain yet the same bond strength standards equivalent to metal-ceramic systems. Therefore, despite the esthetic appeal of all-ceramic restorations, the adhesion between the porcelain and zirconia framework is still an issue considering the long term success of the restoration.

  14. Effect of artificial saliva contamination on adhesion of dental restorative materials.

    PubMed

    Shimazu, Kisaki; Karibe, Hiroyuki; Ogata, Kiyokazu

    2014-01-01

    The purpose of this study was to evaluate the effects of artificial saliva contamination on three restorative materials, namely, a glass ionomer cement (GIC), a resin-modified GIC (RMGIC), and a composite resin (CR), for which two different etching adhesive systems were used. Thus, three surface conditions were created on bovine teeth using artificial saliva: control, mild saliva contamination, and severe saliva contamination. The dentin bond strength for CR was significantly lower after artificial saliva contamination. There were, however, no significant differences among the three surface conditions in terms of the dentin and enamel bond strengths of GIC and RMGIC. Moreover, CR exhibited significantly greater microleakage after artificial saliva contamination, whereas no significant differences were found in GIC and RMGIC. The results showed that artificial saliva contamination did not affect the shear bond strengths of GIC and RMGIC or their degrees of microleakage.

  15. Improving flexural strength of dental restorative ceramics using laser interference direct structuring

    SciTech Connect

    Daniel, Claus; Drummond, James; Giordano, Russell A.

    2008-01-01

    Zirconia and alumina ceramics restorative materials were treated with laser interference direct structuring using the third harmonic of a short pulse Nd:YAG and tested in a three-point bending test to measure the flexural strength. The surface was restructured in a periodic line like pattern with controlled surface porosity and a surface composite pattern. The composite consist of two different defect states rather than different phase compositions. The resulting mechanical properties are a function of the number of laser pulses, laser energy, and angle in between the laser beams defining the periodic feature distance. This composite effect is comparable with a laminate showing increasing stiffness with decreasing layer thickness. The material s fracture strength could be controlled through the three mentioned laser parameters and in an initial study significantly improved by up to 50% from initial 422 MPa to 630 MPa for alumina and 833 MPa to 1250 MPa for zirconia.

  16. The effect of acrylate-based dental adhesive solvent content on microleakage in composite restorations

    PubMed Central

    Mirzakhani, Mahboubeh; Mousavinasab, Sayed Mostafa; Atai, Mohammad

    2016-01-01

    Background: This study aimed to evaluate the effect of different percentages of ethanol solvent of an experimental methacrylate-based dentin bonding agent containing polyhedral oligomeric silsesquioxanes (POSS) on the microleakage of resin composite restorations. Materials and Methods: In this experimental study, 42 extracted human premolar teeth used and 84 standard Class V cavities were prepared on the buccal and lingual surfaces of the teeth. The teeth were divided into 6 groups of 7. Experimental bonding agents with different percentages of solvent were used in 5 groups and Single Bond® as a control. The teeth were restored with resin composite and subjected to thermal cycling test. Teeth were then immersed in a solution of 2% basic fuchsine dye for 24 h and sectioned buccolingually and scored using stereomicroscope with ×32 magnification. Microleakage data were analyzed using the Kruskal–Wallis, Mann–Whitney U, and Wilcoxon tests. Results: There were significant differences between the microleakage enamel margins (P = 0.036) and dentinal margins (P = 0.008) in all the groups. These significant differences were seen between the control group and groups containing 46 wt% solvent (P = 0.011), 46 wt% and 31 wt% solvent in dentinal (P = 0.027), 31 wt% and 0 wt% in enamel (P = 0.021), also 0 wt% and control in enamel (P = 0.039), and dentinal margins microleakage (P = 0.004). The microleakage in dentinal margins was higher than enamel margins (P < 0.001). In the groups with 46 wt% solvent (P = 0.103), 0 wt% (P = 0.122), and control group (P = 0.096), however, this difference was not significant. Conclusion: The adhesive containing 31 wt% solvent showed the least marginal microleakage, presence of POSS filler may also result in the reduction of microleakage. PMID:28182040

  17. Highly-translucent, strong and aging-resistant 3Y-TZP ceramics for dental restoration by grain boundary segregation.

    PubMed

    Zhang, Fei; Vanmeensel, Kim; Batuk, Maria; Hadermann, Joke; Inokoshi, Masanao; Van Meerbeek, Bart; Naert, Ignace; Vleugels, Jef

    2015-04-01

    Latest trends in dental restorative ceramics involve the development of full-contour 3Y-TZP ceramics which can avoid chipping of veneering porcelains. Among the challenges are the low translucency and the hydrothermal stability of 3Y-TZP ceramics. In this work, different trivalent oxides (Al2O3, Sc2O3, Nd2O3 and La2O3) were selected to dope 3Y-TZP ceramics. Results show that dopant segregation was a key factor to design hydrothermally stable and high-translucent 3Y-TZP ceramics and the cation dopant radius could be used as a controlling parameter. A large trivalent dopant, oversized as compared to Zr(4+), exhibiting strong segregation at the ZrO2 grain boundary was preferred. The introduction of 0.2 mol% La2O3 in conventional 0.1-0.25 wt.% Al2O3-doped 3Y-TZP resulted in an excellent combination of high translucency and superior hydrothermal stability, while retaining excellent mechanical properties.

  18. Chipping fracture resistance of dental CAD/CAM restorative materials: Part 2. Phenomenological model and the effect of indenter type

    PubMed Central

    Quinn, G.D.; Giuseppetti, A.A.; Hoffman, K.H.

    2014-01-01

    The edge chipping resistances of six CAD/CAM dental restoration materials are analyzed and correlated to other mechanical properties. A new quadratic relationship that is based on a phenomenological model is presented. Objective The purpose of this study was to further analyze the edge chipping resistance of the brittle materials evaluated in Part 1. One objective was to determine why some force-distance trends were linear and others were nonlinear. A second objective was to account for differences in chipping resistance with indenter type. Methods Edge chipping experiments were conducted with different indenters, including some custom-made sharp conical indenters. A new force – distance quadratic expression was correlated to the data and compared to the linear and power law trends. Results The new quadratic function was an excellent fit in every instance. It can account for why some materials can be fit by a linear trend, while others can be fit by the power law trend. The effects of indenter type are accounted for variations in crack initiation and by the wedging stresses once an indentation hole is created. Significance The new quadratic force – edge distance function can be used with edge chipping data for all brittle materials, not just those evaluated in this study. The data trends vary from linear to nonlinear depending upon the material’s hardness, fracture toughness, and elastic modulus. PMID:24685179

  19. Identification through X-ray fluorescence analysis of dental restorative resin materials: a comprehensive study of noncremated, cremated, and processed-cremated individuals.

    PubMed

    Bush, Mary A; Miller, Raymond G; Prutsman-Pfeiffer, Jennifer; Bush, Peter J

    2007-01-01

    Tooth-colored restorative materials are increasingly being placed in the practice of modern dentistry, replacing traditional materials such as amalgam. Many restorative resins have distinct elemental compositions that allow identification of brand. Not only are resins classifiable by elemental content, but they also survive extreme conditions such as cremation. This is of significance to the forensic odontologist because resin uniqueness adds another level of certainty in victim identification, especially when traditional means are exhausted. In this three-part study, unique combinations of resins were placed in six human cadavers (total 70 restorations). Simulated ante-mortem dental records were created. In a blind experiment, a portable X-ray fluorescence (XRF) unit was used to locate and identify the resin brands placed in the dentition. The technique was successful in location and brand identification of 53 of the restorations, which was sufficient to enable positive victim identification among the study group. This part of the experiment demonstrated the utility of portable XRF in detection and analysis of restorative materials for victim identification in field or morgue settings. Identification of individuals after cremation is a more difficult task, as the dentition is altered by shrinkage and fragmentation, and may not be comparable with a dental chart. Identification of processed cremains is a much greater challenge, as comminution obliterates all structural relationships. Under both circumstances, it is the nonbiological artifacts that aid in identification. Restorative resin fillings can survive these conditions, and can still be named by brand utilizing elemental analysis. In a continuation of the study, the cadavers were cremated in a cremation retort under standard mortuary conditions. XRF was again used to analyze retrieved resins and to identify the individuals based on restorative materials known to exist from dental records. The cremains were

  20. The incorporation of nanoparticles into conventional glass-ionomer dental restorative cements.

    PubMed

    Gjorgievska, Elizabeta; Van Tendeloo, Gustaaf; Nicholson, John W; Coleman, Nichola J; Slipper, Ian J; Booth, Samantha

    2015-04-01

    Conventional glass-ionomer cements (GICs) are popular restorative materials, but their use is limited by their relatively low mechanical strength. This paper reports an attempt to improve these materials by incorporation of 10 wt% of three different types of nanoparticles, aluminum oxide, zirconium oxide, and titanium dioxide, into two commercial GICs (ChemFil® Rock and EQUIA™ Fil). The results indicate that the nanoparticles readily dispersed into the cement matrix by hand mixing and reduced the porosity of set cements by filling the empty spaces between the glass particles. Both cements showed no significant difference in compressive strength with added alumina, and ChemFil® Rock also showed no significant difference with zirconia. By contrast, ChemFil® Rock showed significantly higher compressive strength with added titania, and EQUIA™ Fil showed significantly higher compressive strength with both zirconia and titania. Fewer air voids were observed in all nanoparticle-containing cements and this, in turn, reduced the development of cracks within the matrix of the cements. These changes in microstructure provide a likely reason for the observed increases in compressive strength, and overall the addition of nanoparticles appears to be a promising strategy for improving the physical properties of GICs.

  1. [Tooth color matching systems and communication with dental laboratory in indirect restorations: 2011 update].

    PubMed

    Ginzburg, M; Gilboa, I

    2012-01-01

    There has been many technological developments in the last decade. Today's shade-matching technologies have been developed in an effort to increase the success of color matching, communication, reproduction and verification in clinical dentistry and, ultimately, to increase the efficiency of esthetic restorative work within any practice. In general, the output of the color measurements can be classified and specified in several ways. The most common systems for describing color are Munsell's System and the international Commission on Illumination (CIE) L a b color system. Albert Munsell described color as a three-dimensional phenomenon. He described the three dimensions as hue, value (brightness), and chroma (saturation). Visual colour determination by comparison of teeth and shade guides is the most frequently applied method in dentistry. Vitapan Classical (Vita Zahnfabrik, Germany) and its derivations(evidence-based Vitapan 3D-Master shade guide and Linearguide) are the most commonly used shade guides. However, several factors can influence consistency of visual colour selection and specification: individual colour matching ability may vary, the colour perception of any individual may show temporal variation, the range of shades available is inadequate and does not cover the complete colour space of natural teeth, the shade guide tabs are not systematically distributed in their colour space, and changes in lighting conditions can cause alterations in perceived colour. instruments for clinical shade-matching encompass spectrophotometers, colorimeters and digital imaging systems. It can be concluded that different devices have different accuracy and precision. Colorimeters are significantly less reliable than spectrophotometers and digital cameras. Benefits and limitations exist, and the clinician must consider how the technology relates to expectations and needs. Combination of visual colour determination (Vitapan 3D-Master shade guide and Linearguide) with

  2. Atomic force microscopy in vitro study of surface roughness and fractal character of a dental restoration composite after air-polishing

    PubMed Central

    2010-01-01

    Background Surface roughness is the main factor determining bacterial adhesion, biofilm growth and plaque formation on the dental surfaces in vivo. Air-polishing of dental surfaces removes biofilm but can also damage the surface by increasing its roughness. The purpose of this study was to investigate the surface damage of different conditions of air-polishing performed in vitro on a recently introduced dental restorative composite. Methods Abrasive powders of sodium bicarbonate and glycine, combined at different treatment times (5, 10 and 30 s) and distances (2 and 7 mm), have been tested. The resulting root mean square roughness of the surfaces has been measured by means of atomic force microscopy, and the data have been analyzed statistically to assess the significance. Additionally, a fractal analysis of the samples surfaces has been carried out. Results The minimum surface roughening was obtained by air-polishing with glycine powder for 5 s, at either of the considered distances, which resulted in a mean roughness of ~300 nm on a 30 × 30 μm2 surface area, whereas in the other cases it was in the range of 400-750 nm. Both untreated surfaces and surfaces treated with the maximum roughening conditions exhibited a fractal character, with comparable dimension in the 2.4-2.7 range, whereas this was not the case for the surfaces treated with the minimum roughening conditions. Conclusions For the dental practitioner it is of interest to learn that use of glycine in air polishing generates the least surface roughening on the considered restorative material, and thus is expected to provide the lowest rate of bacterial biofilm growth and dental plaque formation. Furthermore, the least roughening behaviour identified has been correlated with the disappearance of the surface fractal character, which could represent an integrative method for screening the air polishing treatment efficacy. PMID:20939880

  3. Evaluation of low-contrast perceptibility in dental restorative materials under the influence of ambient light conditions

    PubMed Central

    Lobo, I C; Lemos, A L B; Aguiar, M F

    2015-01-01

    Objectives: This study aimed to assess how details on dental restorative composites with different radio-opacities are perceived under the influence of ambient light. Methods: Resin composite step wedges (six steps, each 1-mm thick) were custom manufactured from three materials, respectively: (M1) Filtek™ Z350 (3M/ESPE, Saint Paul, MN); (M2) Prisma AP.H™ (Dentsply International Inc., Brazil) and (M3) Glacier® (SDI Limited, Victoria, Australia). Each step of the manufactured wedge received three standardized drillings of different diameters and depths. An aluminium (Al) step wedge with 12 steps (1-mm thick) was used as an internal standard to calculate the radio-opacity as pixel intensity values. Standardized digital images of the set were obtained, and 11 observers independently recorded the images, noting the number of noticeable details (drillings) under 2 dissimilar conditions: in a light environment (light was turned on in the room) and in low-light conditions (light in the room was turned off). The differences between images in terms of the number of details that were observed were statistically compared using ANOVA, Cronbach's alpha coefficient and Wilcoxon and Kruskal–Wallis tests, with a significance level setting of 5% (α = 0.05). Results: The M2 showed higher radio-opacity, the M1 displayed intermediate radio-opacity and the M3 showed lower radio-opacity, respectively; however, all three were without significance (p > 0.05) compared with each other. The differences in radio-opacity resulted in a significant variation (p < 0.05) in the number of noticeable details in the image, which were influenced by characteristics of details, in addition to the ambient-light level. Conclusions: The radio-opacity of materials and ambient light can affect the perception of details in digital radiographic images. PMID:25629721

  4. Increased mercury release from dental amalgam restorations after exposure to electromagnetic fields as a potential hazard for hypersensitive people and pregnant women.

    PubMed

    Mortazavi, Ghazal; Mortazavi, S M J

    2015-01-01

    Over the past decades, the use of common sources of electromagnetic fields such as Wi-Fi routers and mobile phones has been increased enormously all over the world. There is ongoing concern that exposure to electromagnetic fields can lead to adverse health effects. It has recently been shown that even low doses of mercury are capable of causing toxicity. Therefore, efforts are initiated to phase down or eliminate the use of mercury amalgam in dental restorations. Increased release of mercury from dental amalgam restorations after exposure to electromagnetic fields such as those generated by MRI and mobile phones has been reported by our team and other researchers. We have recently shown that some of the papers which reported no increased release of mercury after MRI, may have some methodological errors. Although it was previously believed that the amount of mercury released from dental amalgam cannot be hazardous, new findings indicate that mercury, even at low doses, may cause toxicity. Based on recent epidemiological findings, it can be claimed that the safety of mercury released from dental amalgam fillings is questionable. Therefore, as some individuals tend to be hypersensitive to the toxic effects of mercury, regulatory authorities should re-assess the safety of exposure to electromagnetic fields in individuals with amalgam restorations. On the other hand, we have reported that increased mercury release after exposure to electromagnetic fields may be risky for the pregnant women. It is worth mentioning that as a strong positive correlation between maternal and cord blood mercury levels has been found in some studies, our findings regarding the effect of exposure to electromagnetic fields on the release of mercury from dental amalgam fillings lead us to this conclusion that pregnant women with dental amalgam fillings should limit their exposure to electromagnetic fields to prevent toxic effects of mercury in their fetuses. Based on these findings, as infants

  5. Spectrophotometric evaluation of shade reproduction of pressable all-ceramic system on un-stained and stained tooth: An in vitro study

    PubMed Central

    Pande, Neelam; Kolarkar, Maithili S.

    2016-01-01

    Purpose: To evaluate the shade reproduction of a pressable all-ceramic system placed on unstained and stained extracted maxillary central incisor using a color measurement spectrophotometer. In addition, to compare shade reproduction of this material with low translucency and medium opacity on unstained tooth and medium and high opacity on stained tooth. Materials and Methods: Total 45 discs, with difference in the opacity of core, were used. After spectrophotometric evaluation, shade reproduction of the discs was compared and calculated by formula: Δ E* = ([Δ L*]2+ [Δ a*]2+ [Δ b*]2)1/2. Results: Student's t-test showed that in a sample of 15, the values of Δ E* for Group I - LT (Us.T.) lie between 0 and l, for Group II - MO (for Us. as well as S.T.) between l and 2, for Group III - HO (S.T.) are all above 5. Comparison among groups after t-test showed that mean Δ E* values of Group I - LT is less than Group II - MO for the unstained tooth, Δ E* for Group II - MO is less than average Δ E* value of Group III - HO for stained tooth. Conclusion: All-ceramic with low translucency can be used for the fabrication of restoration on the unstained tooth as it gives the best shade reproduction. The medium opacity material may be used on the unstained as well as on stained tooth. However, the clinical implication of high opacity is limited when applied over the stained tooth as it is giving a shade reproduction, which is not within acceptable limits. PMID:27134430

  6. Effect of resin coating on adhesion and microleakage of computer-aided design/computer-aided manufacturing fabricated all-ceramic crowns after occlusal loading: a laboratory study.

    PubMed

    Kitayama, Shuzo; Pilecki, Peter; Nasser, Nasser A; Bravis, Theodora; Wilson, Ron F; Nikaido, Toru; Tagami, Junji; Watson, Timothy F; Foxton, Richard M

    2009-08-01

    This study investigated the effect of resin coating and occlusal loading on adhesion and microleakage of all-ceramic crowns. Molars were prepared for an all-ceramic crown and were divided into two groups: non-coated (control) and resin-coated with Clearfil Tri-S Bond. Crowns were fabricated using CEREC 3 and cemented using Clearfil Esthetic Cement. After 24 h of storage in water, the restored teeth in each group were divided into two subgroups: unloaded, or loaded while stored in water. Mechanical loading was achieved with an axial force of 80 N at 2.5 cycles s(-1) for 250,000 cycles. After immersion in Rhodamine B, the specimens were sectioned and processed for microleakage evaluation by confocal microscopy, which was followed by further sectioning for microtensile bond testing. Loading had no significant effect on microleakage in either the resin-coated or non-resin-coated groups. Resin coating did not reduce the microleakage at the dentine interface but increased the microleakage at the enamel interface. All the beams fractured during slicing when non-coated and loaded. The bond strengths of non-coated and unloaded, resin-coated and unloaded, and resin-coated and loaded groups were 15.82 +/- 4.22, 15.17 +/- 5.24, and 12.97 +/- 5.82 MPa, respectively. Resin coating with Clearfil Tri-S Bond improved the bonding of resin cement to dentine for loaded specimens. However, it was not effective in reducing the microleakage, regardless of whether it was loaded or unloaded.

  7. The all-ceramic, inlay supported fixed partial denture. Part 2. Fixed partial denture design: a finite element analysis.

    PubMed

    Thompson, M C; Field, C J; Swain, M V

    2011-09-01

    The clinical use of all-ceramic crowns and fixed partial dentures has seen widespread adoption over the past few years due to their increasing durability and longevity. However, the application of inlays as an abutment design has not been as readily embraced because of their relatively high failure rates. With the use of an idealized inlay preparation design and prosthesis form which better distributes the tensile stresses, it is possible to utilize the inlay as support for an all-ceramic fixed partial denture. Utilizing a three-dimensional finite element analysis, a direct comparison of the inlay supported all-ceramic bridge against the traditional full crown supported all-ceramic bridge is made. The results demonstrate that peak stresses in the inlay bridge are around 20% higher than in the full crown supported bridge with von Mises peaking at about 730 MPa when subjected to theoretical average maximum bite force in the molar region of 700 N, which is similar to the ultimate tensile strengths of current zirconia based ceramics.

  8. Marginal integrity of turkom-cera compared to other all-ceramic materials: effect of finish line.

    PubMed

    Al-Makramani, Bandar M A; Razak, Abdul A A; Abu-Hassan, Mohamed I; Sulaiman, Eshamsul; Loon, Lui Joo; Yahya, Noor Azlin

    2011-01-01

    The aim of this study was to evaluate the marginal adaptation of Turkom-Cera all-ceramic crowns compared to In-Ceram and Procera AllCeram systems. The influence of finish line design (chamfer or shoulder) on the marginal adaptation of Turkom-Cera all-ceramic crowns was also investigated. Thirty human premolars were prepared with chamfer margins and assigned to either the Turkom-Cera, In-Ceram, or Procera system group. In addition, 10 premolars were prepared with rounded shoulder finish lines and assigned to an additional Turkom-Cera group. Ceramic copings (0.6-mm thick) were fabricated for each group following the manufacturers' instructions. The copings were seated on abutments using a special holding device that facilitated uniform loading, and marginal adaptation was assessed using a stereomicroscope. Data were analyzed using analysis of variance, the Tukey HSD post hoc test, and an independent samples t test. There was a statistically significant difference regarding marginal adaptation among the three all-ceramic systems (P < .05). There were no significant differences in the mean marginal discrepancies of Turkom-Cera crowns among chamfer and shoulder finish line groups (P > .05). Within the limitations of this study, the marginal discrepancies were all within the clinically acceptable standard. Int J Prosthodont 2011;24:379-381.

  9. Internal fit of two all-ceramic systems and metal-ceramic crowns

    PubMed Central

    MARTINS, Leandro Moura; LORENZONI, Fabio Cesar; de MELO, Alcides Oliveira; da SILVA, Luciana Mendonça; de OLIVEIRA, José Luiz G.; de OLIVEIRA, Pedro Cesar Garcia; BONFANTE, Gerson

    2012-01-01

    Objectives The aim of this study was to investigate the internal fit (IF) of glass-infiltrated alumina (ICA - In-Ceram Alumina), yttria-stabilized tetragonal zirconia polycrystals (Y-TZP - IPS e.max ZirCAD), and metal-ceramic (MC - Ni-Cr alloy) crowns. Material and Methods Sixty standardized resin-tooth replicas of a maxillary first molar were produced for crown placement and divided into 3 groups (n=20 each) according to the core material used (metal, ICA or Y-TZP). The IF of the crowns was measured using the replica technique, which employs a light body polyvinyl siloxane impression material to simulate the cement layer thickness. The data were analyzed according to the surfaces obtained for the occlusal space (OS), axial space (AS) and total mean (TM) using two-way ANOVA with Tukey's multiple comparison test (p<0.05). Results No differences among the different areas were detected in the MC group. For the Y-TZP and ICA groups, AS was statistically lower than both OS and TM. No differences in AS were observed among the groups. However, OS and TM showed significantly higher values for ICA and Y-TZP groups than MC group. Comparisons of ICA and Y-TZP revealed that OS was significantly lower for Y-TZP group, whereas no differences were observed for TM. Conclusions The total mean achieved by all groups was within the range of clinical acceptability. However, the metal-ceramic group demonstrated significantly lower values than the all-ceramic groups, especially in OS. PMID:22666843

  10. Influence of marginal fit and cement types on microleakage of all-ceramic crown systems.

    PubMed

    Yüksel, Ece; Zaimoğlu, Ali

    2011-01-01

    The purpose of this study was to evaluate the effects of both marginal fit and cementing with different luting agents on the microleakage of all-ceramic crown systems. Thirty-six extracted upper central incisors were prepared for full-coverage crowns and were divided into three groups. Group 1: CAD/CAM-fabricated ZrO2, Group 2: Heat-pressed lithium-disilicate, and Group 3: Cast Cr-Co copings as the control group. Copings were made following standard techniques, and groups were assigned cementation with either self-adhesive resin cement (A) or glass-ionomer luting cement (B). The specimens were subjected to thermocycling, immersed in basic fuchsin solution, sectioned mesiodistally and buccolingually. The surface of each section was digitally photographed under a stereomicroscope. Microleakage was scored using a five-point scale, and the marginal gap was measured using image analysis software. Data were statistically analyzed using 2-way ANOVA, Kruskal-Wallis, and Mann-Whitney U tests (α: 0.05). The marginal discrepancy of each group was 82.7 ± 7 µm, 92.6 ± 4 µm and 96.5 ± 7 µm respectively. Group 1 showed significantly smaller gaps than Group 3 (P = 0.042). Self-adhesive resin cement (A) showed a lower level of microleakage than glass-ionomer luting cement (B) in all groups (P = 0.029). Microleakage scores of '0' were 83% for 1A, 50% for 1B, 50% for 2A, 16% for 2B, 33% for 3A and none for 3B. Marginal discrepancy and cement type both had significant effects on microleakage. Lower levels of microleakage were recorded with self-adhesive resin cement, while CAD/CAM-fabricated ZrO2 copings showed smaller marginal discrepancy and less microleakage in comparison to cast Cr-Co.

  11. Suppression effects of dental glass-ceramics with polarization-induced highly dense surface charges against bacterial adhesion.

    PubMed

    Nozaki, Kosuke; Koizumi, Hiroki; Horiuchi, Naohiro; Nakamura, Miho; Okura, Toshinori; Yamashita, Kimihiro; Nagai, Akiko

    2015-01-01

    This study investigated the surface characteristics and antibacterial ability capacity of surface-improved dental glass-ceramics by an electrical polarization process. Commercially available dental glass-ceramic materials were electrically polarized to induce surface charges in a direct current field by heating. The surface morphology, chemical composition, crystal structure, and surface free energy (SFE) were evaluated using scanning electron microscopy, energy dispersive X-ray spectrometry, X-ray diffraction, and water droplet methods, respectively. The antibacterial capacity was assessed by a bacterial adhesion test using Streptococcus mutans. Although the surface morphology, chemical composition, and crystal structure were not affected by electrical polarization, the polar component and total SFE were enhanced. After 24 h incubation at 37ºC, bacterial adhesion to the polarized samples was inhibited. The electrical polarization method may confer antibacterial properties on prosthetic devices, such as porcelain fused to metal crowns or all ceramic restorations, without any additional bactericidal agents.

  12. Multidisciplinary Approach for Restoring Function and Esthetics in a Patient with Amelogenesis Imperfecta: A Clinical Report

    PubMed Central

    Kamble, Vaibhav D; Parkhedkar, Rambhau D

    2013-01-01

    Amelogenesis Imperfecta (AI) is a genetically determined and enamel mineralization defect reported, depicted as “Hereditary brown teeth.” AI is characterized as a clinical entity and its clinical manifestations, histological appearance, and genetic pattern are characterized by their heterogeneity. The need for prosthodontic management of this group of patients varies. Some patients need oral hygiene instructions only, whereas others need extensive dental treatment that includes composite restorations, metal ceramic crowns, all ceramic crowns, porcelain veneers. A 20-year-old male patient presented with sensitive, discoloured, and mutilated teeth, with a decreased vertical dimension of occlusion. The 4-year recall examination revealed no pathology associated with the full mouth rehabilitation, and the patient’s aesthetic and functional expectations were satisfied. The rehabilitation included all-ceramic crowns on anterior teeth and metal-ceramic crowns on posterior teeth following endodontic treatment and a crown-lengthening procedure for eliminating tooth sensitivity, improving the aesthetics and occlusion, and for restoring function. PMID:24551735

  13. Evaluation of the effect of tooth and dental restoration material on electron dose distribution and production of photon contamination in electron beam radiotherapy.

    PubMed

    Bahreyni Toossi, Mohammad Taghi; Ghorbani, Mahdi; Akbari, Fatemeh; Mehrpouyan, Mohammad; Sobhkhiz Sabet, Leila

    2016-03-01

    The aim of this study is to evaluate the effect of tooth and dental restoration materials on electron dose distribution and photon contamination production in electron beams of a medical linac. This evaluation was performed on 8, 12 and 14 MeV electron beams of a Siemens Primus linac. MCNPX Monte Carlo code was utilized and a 10 × 10 cm(2) applicator was simulated in the cases of tooth and combinations of tooth and Ceramco C3 ceramic veneer, tooth and Eclipse alloy and tooth and amalgam restoration materials in a soft tissue phantom. The relative electron and photon contamination doses were calculated for these materials. The presence of tooth and dental restoration material changed the electron dose distribution and photon contamination in phantom, depending on the type of the restoration material and electron beam's energy. The maximum relative electron dose was 1.07 in the presence of tooth including amalgam for 14 MeV electron beam. When 100.00 cGy was prescribed for the reference point, the maximum absolute electron dose was 105.10 cGy in the presence of amalgam for 12 MeV electron beam and the maximum absolute photon contamination dose was 376.67 μGy for tooth in 14 MeV electron beam. The change in electron dose distribution should be considered in treatment planning, when teeth are irradiated in electron beam radiotherapy. If treatment planning can be performed in such a way that the teeth are excluded from primary irradiation, the potential errors in dose delivery to the tumour and normal tissues can be avoided.

  14. All-Ceramic Body Flap Qualified for Space Flight on X38

    NASA Astrophysics Data System (ADS)

    Pfeiffer, H.; Peetz, K.

    2002-01-01

    Ceramic matrix composite (CMC) materials allow design of high-temperature resistant, light and robust structures. CMC materials with silicon-carbide matrix reinforced by carbon fibers (C/SiC) show constant strength and damage-tolerant behavior up to very high temperatures. CMC thermal protection systems and hot structures have been developed in Europe over many years. MAN Technologie developed the necessary technologies to create the technological basis for CMC structures for future, more economical and reusable launch vehicles. Within the German space technology program TETRA (Technologies for Future Space Transportation Systems) body flaps were developed for X-38 by MAN Technologie. Key technologies like high strength oxidation protected CMC materials, manufacturing processes for large and complex structures, advanced high temperature lubricant coating combinations for bearings, joining with ceramic fasteners, metal-to-ceramic interfaces as well as dynamic seals are required for hot structures like control surfaces for re-entry vehicles. Because of the high heat and mechanical loads of a lifting body together with the low mass requirements the body flaps for NASA's X-38 re-entry vehicle V-201were selected to demonstrate as a first flight maturity of a large and complex ceramic structure. The flaps are designed as an all-ceramic, load-carrying hot structure, which needs no heavy metallic primary structure and no additional thermal protection tiles and subsequently offers considerable mass and volume savings. The X-38 body flaps are conceived as a revolutionary step forward. The twin flaps, each with the size of 1.6 m x 1.4 m (5.25 ft x 4.6 ft) and the low weight of 68 kg (150 lb) are all made of C/SiC material to operate up to temperatures of 1800 C (3.270 F) in oxidizing atmosphere while they are deflectable under high mechanical loads up to 50 kN (11.260 lbf) at the same time. The flaps are deflected about the hinge axis on two ceramic bearings and moved by an

  15. High elastic modulus nanopowder reinforced resin composites for dental applications

    NASA Astrophysics Data System (ADS)

    Wang, Yijun

    2007-12-01

    Dental restorations account for more than $3 billion dollars a year on the market. Among them, all-ceramic dental crowns draw more and more attention and their popularity has risen because of their superior aesthetics and biocompatibility. However, their relatively high failure rate and labor-intensive fabrication procedure still limit their application. In this thesis, a new family of high elastic modulus nanopowder reinforced resin composites and their mechanical properties are studied. Materials with higher elastic modulus, such as alumina and diamond, are used to replace the routine filler material, silica, in dental resin composites to achieve the desired properties. This class of composites is developed to serve (1) as a high stiffness support to all-ceramic crowns and (2) as a means of joining independently fabricated crown core and veneer layers. Most of the work focuses on nano-sized Al2O3 (average particle size 47 nm) reinforcement in a polymeric matrix with 50:50 Bisphenol A glycidyl methacrylate (Bis-GMA): triethylene glycol dimethacrylate (TEGDMA) monomers. Surfactants, silanizing agents and primers are examined to obtain higher filler levels and enhance the bonding between filler and matrix. Silane agents work best. The elastic modulus of a 57.5 vol% alumina/resin composite is 31.5 GPa compared to current commercial resin composites with elastic modulus <15 GPa. Chemical additives can also effectively raise the hardness to as much as 1.34 GPa. Besides>alumina, diamond/resin composites are studied. An elastic modulus of about 45 GPa is obtained for a 57 vol% diamond/resin composite. Our results indicate that with a generally monodispersed nano-sized high modulus filler, relatively high elastic modulus resin-based composite cements are possible. Time-dependent behavior of our resin composites is also investigated. This is valuable for understanding the behavior of our material and possible fatigue testing in the future. Our results indicate that with

  16. Fit of zirconia all-ceramic crowns with different cervical margin designs, before and after porcelain firing and glazing.

    PubMed

    Miura, Shoko; Inagaki, Ryoichi; Kasahara, Shin; Yoda, Masanobu

    2014-01-01

    The purpose of this study is to investigate the fit of zirconia cores and all-ceramic crowns prepared with different cervical margin designs. The radius of curvature between the axial wall and the occlusal surface was set to 1 mm in an abutment using the cervical shoulder marginal design (S) and to 0.2 and 0.5 mm in abutments with round shoulders (0.2RS and 0.5RS, respectively). The internal gaps of the cores were 45-138 μm (S), 41-141 μm (0.2RS), and 43-133 μm (0.5RS). The internal gaps of the all-ceramic crowns were 40-115 μm (S), 45-113 μm (0.2RS), and 42-126 μm (0.5RS). There were no significant differences in one-way ANOVA for any region in any marginal design before and after firing the porcelain. The marginal gaps between the all-ceramic crowns and dies were 27 ± 25 (S), 30 ± 29 (0.2RS), and 24 ± 27 μm (0.5RS), again with no significant differences in one-way ANOVA.

  17. Dental OCT

    NASA Astrophysics Data System (ADS)

    Wilder-Smith, Petra; Otis, Linda; Zhang, Jun; Chen, Zhongping

    This chapter describes the applications of OCT for imaging in vivo dental and oral tissue. The oral cavity is a diverse environment that includes oral mucosa, gingival tissues, teeth and their supporting structures. Because OCT can image both hard and soft tissues of the oral cavity at high resolution, it offers the unique capacity to identity dental disease before destructive changes have progressed. OCT images depict clinically important anatomical features such as the location of soft tissue attachments, morphological changes in gingival tissue, tooth decay, enamel thickness and decay, as well as the structural integrity of dental restorations. OCT imaging allows for earlier intervention than is possible with current diagnostic modalities.

  18. Dental Implants.

    PubMed

    Zohrabian, Vahe M; Sonick, Michael; Hwang, Debby; Abrahams, James J

    2015-10-01

    Dental implants restore function to near normal in partially or completely edentulous patients. A root-form implant is the most frequently used type of dental implant today. The basis for dental implants is osseointegration, in which osteoblasts grow and directly integrate with the surface of titanium posts surgically embedded into the jaw. Radiologic assessment is critical in the preoperative evaluation of the dental implant patient, as the exact height, width, and contour of the alveolar ridge must be determined. Moreover, the precise locations of the maxillary sinuses and mandibular canals, as well as their relationships to the site of implant surgery must be ascertained. As such, radiologists must be familiar with implant design and surgical placement, as well as augmentation procedures utilized in those patients with insufficient bone in the maxilla and mandible to support dental implants.

  19. Assessment of exposures and potential risks to the US adult population from the leaching of elements from gold and ceramic dental restorations.

    PubMed

    Richardson, G Mark; James, Kyle Jordan; Peters, Rachel Elizabeth; Clemow, Scott Richard; Siciliano, Steven Douglas

    2016-01-01

    Using data from the 2001 to 2004 US National Health and Nutrition Examination Survey (NHANES) on the number and placement of tooth restorations in adults, we quantified daily doses due to leaching of elements from gold (Au) alloy and ceramic restorative materials. The elements with the greatest leaching rates from these materials are often the elements of lowest proportional composition. As a result, exposure due to wear will predominate for those elements of relatively high proportional composition, while exposure due leaching may predominate for elements of relatively low proportional composition. The exposure due to leaching of silver (Ag) and palladium (Pd) from Au alloys exceeded published reference exposure levels (RELs) for these elements when multiple full surface crowns were present. Six or more molar crowns would result in exceeding the REL for Ag, whereas three or more crowns would be necessary to exceed the REL for Pd. For platinum (Pt), the majority of tooth surfaces, beyond just molar crowns, would be necessary to exceed the REL for Pd. Exposures due to leaching of elements from ceramic dental materials were less than published RELs for all components examined here, including having all restorations composed of ceramic.

  20. Design maps for failure of all-ceramic layer structures in concentrated cyclic loading

    PubMed Central

    Bhowmick, Sanjit; Meléndez-Martínez, Juan José; Zhang, Yu; Lawn, Brian R.

    2009-01-01

    A study is made of the competition between failure modes in ceramic-based bilayer structures joined to polymer-based substrates, in simulation of dental crown-like structures with a functional but weak “veneer” layer bonded onto a strong “core” layer. Cyclic contact fatigue tests are conducted in water on model flat systems consisting of glass plates joined to glass, sapphire, alumina or zirconia support layers glued onto polycarbonate bases. Critical numbers of cycles to take each crack mode to failure are plotted as a function of peak contact load on failure maps showing regions in which each fracture mode dominates. In low-cycle conditions, radial and outer cone cracks are competitive in specimens with alumina cores, and outer cone cracks prevail in specimens with zirconia cores; in high-cycle conditions, inner cone cracks prevail in all cases. The roles of other factors, e.g. substrate modulus, layer thickness, indenter radius and residual stresses from specimen preparation, are briefly considered. PMID:19562095

  1. Simplified digital workflow for dental implant restoration on a stock abutment using an intraoral scanner: A dental technique.

    PubMed

    Kim, Jong-Eun; Park, Ji-Hyun; Moon, Hong-Seok; Shim, June-Sung

    2017-02-17

    A straightforward digital restorative method based on a library of stock abutments is presented. Precisely scanned data of laboratory analog components of the stock abutment were obtained using a tabletop scanner to produce the library. The stock abutment and surrounding teeth, opposing arch, and occlusal information were recorded using an intraoral scanner. After transferring the scanned data to computer-aided design software, an appropriate library file for the abutment connected within the mouth was matched in order to design the prosthesis.

  2. The significance of cone beam computed tomography for the visualization of anatomical variations and lesions in the maxillary sinus for patients hoping to have dental implant-supported maxillary restorations in a private dental office in Japan

    PubMed Central

    2014-01-01

    Objectives The purpose of the present study was to elucidate the significance of cone bean computed tomography (CBCT) for patients hoping to undergo implant-supported restorations of the maxilla. Therefore, two studies were planned. One was to compare the prevalence of anatomic variations and lesions in the maxillary sinus on CBCT of patients hoping to undergo implant-supported restorations of the maxilla with that in patients with other chief complaints in a private dental office in Japan. The other study was to elucidate the limitations of panoramic radiographs in the detection of anatomic variations and lesions in the maxillary sinus. Study design Sixty-one pairs of panoramic radiographs and CBCT were retrospectively analyzed in two groups of patients, those who hoped to undergo implant-supported restorations in the maxilla (Implant group) and those who did not (Non-implant group). The presence of anatomic variations and lesions in the maxillary sinus were analyzed. Results The detection rate of mucosal thickening was significantly higher in the Implant group than in the Non-implant group. The detection rates for the features analyzed were significantly lower on panoramic radiographs. In particular, the detection rates of internal and anterior locations of some features were noticeably lower on panoramic radiographs. A significant relationship was found between the change in the detection rate on panoramic radiographs and the widths of mucosal thickening or the lengths of the major axis of SOLs in the maxillary sinus. If the width of mucosal thickening or the length of the major axis of SOLs was <3 mm or <4 mm, respectively, the detection rate on panoramic radiographs was significantly decreased. Conclusion CBCT is important for patients hoping to undergo implant-supported restorations of the maxilla because of the mucosal thickening in the maxillary sinus in such patients and their lower detection rates on panoramic radiographs. PMID:24884983

  3. “Struggle to obtain redress”: Women’s experiences of living with symptoms attributed to dental restorative materials and/or electromagnetic fields

    PubMed Central

    Mårell, Lena; Lindgren, Monica; Ternulf Nyhlin, Kerstin; Ahlgren, Christina; Berglund, Anders

    2016-01-01

    The aim of this study was to explore the experiences of illness and the encounters with health care professionals among women who attributed their symptoms and illness to either dental restorative materials and/or electromagnetic fields, despite the fact that research on health effects from dental fillings or electricity has failed to substantiate the reported symptoms. Thirteen women (aged 37–63 years) were invited to the study and a qualitative approach was chosen as the study design, and data were collected using semi-structured interviews. The analysis was conducted with a constant comparative method, according to Grounded Theory. The analysis of the results can be described with the core category, “Struggle to obtain redress,” the two categories, “Stricken with illness” and “A blot in the protocol,” and five subcategories. The core category represents the women's fight for approval and arose in the conflict between their experience of developing a severe illness and the doctors’ or dentists’ rejection of the symptoms as a disease, which made the women feel like malingerers. The informants experienced better support and confirmation from alternative medicine practitioners. However, sick-leave certificates from alternative medicine practitioners were not approved and this led to a continuous cycle of visits in the health care system. To avoid conflicting encounters, it is important for caregivers to listen to the patient's explanatory models and experience of illness, even if a medical answer cannot be given. PMID:27938629

  4. Fracture strength of all-ceramic lithium disilicate and porcelain-fused-to-metal bridges for molar replacement after dynamic loading.

    PubMed

    Chitmongkolsuk, Somsak; Heydecke, Guido; Stappert, Christian; Strub, Joerg R

    2002-03-01

    The replacement of missing posterior teeth using all-ceramic bridges remains a challenge. This study compares the fracture resistance of all-ceramic 3-unit bridges for the replacement of first molars to conventional porcelain-fused-to-metal bridges. Human premolars and molars were used to create two test groups and one control group of 16 specimens each. To simulate clinical parameters, the specimens were exposed to cyclic fatigue loading in an artificial mouth with simultaneous thermocycling. All samples were thereafter exposed to fracture strength testing. Porcelain-fused-to-metal bridges showed significantly higher fracture strengths than all-ceramic bridges. However, the fracture strength of the all-ceramic bridges was higher than peak physiological chewing forces.

  5. Clinical fit of all-ceramic three-unit fixed partial dentures, generated with three different CAD/CAM systems.

    PubMed

    Reich, Sven; Wichmann, Manfred; Nkenke, Emeka; Proeschel, Peter

    2005-04-01

    In this study, the hypothesis was tested that the marginal and internal fit of CAD/CAM fabricated all-ceramic three-unit fixed partial dentures (FPDs) can be as good as in metal-ceramic FPDs. Twenty-four all-ceramic FPDs were fabricated and randomly subdivided into three equally sized groups. Eight frameworks were fabricated using the Digident CAD/CAM system (DIGI), another eight frameworks using the Cerec Inlab system (INLA). Vita Inceram Zirkonia blanks were used for both groups. In a third group frameworks were milled from yttrium-stabilized Zirconium blanks using the Lava system (LAVA). All frameworks were layered with ceramic veneering material. In addition, six three-unit metal-ceramic FPDs served as control group. All FPDs were evaluated using a replica technique with a light body silicone stabilized with a heavy body material. The replica samples were examined under microscope. The medians of marginal gaps were 75 microm for DIGI, 65 microm for LAVA and INLA and 54 microm for the conventional FPDs. Only the DIGI data differed significantly from those of the conventional FPDs. Within the limits of this study, the results suggest that the accuracy of CAD/CAM generated three-unit FPDs is satisfactory for clinical use.

  6. A new design for all-ceramic inlay-retained fixed partial dentures: a report of 2 cases.

    PubMed

    Wolfart, Stefan; Kern, Matthias

    2006-01-01

    In a previous clinical study, all-ceramic resin-bonded 3-unit inlay-retained fixed partial dentures (IRFPDs) had a significantly worse outcome in the posterior region than did crown-retained 3-unit FPDs made from the same material. Debonding or fractures were causes of failure. To improve the clinical outcome of IRFPDs, a new framework design was developed: (1) The inlay retainers were made out of CAD/CAM-manufactured zirconia ceramic to improve fracture resistance, and additional veneering of the inlays was omitted. (2) The inlay retainers were completed with a shallow occlusal inlay (1-mm minimum thickness) and an oral retainer wing (0.6-mm minimum thickness). The wings were designed to reduce stress on the inlay retainer caused by torsion forces when the FPD is loaded nonaxially and to increase the enamel adhesive surface area. The pontic was circumferentially veneered with feldspathic porcelain. The clinical and laboratory procedures of this new treatment modality are described, and 2 exemplary clinical cases are presented. This new preparation and framework design might improve the clinical outcome of all-ceramic resin-bonded IRFPDs. However, adequate evidence of long-term safety and efficacy is required before this new design can be recommended for general clinical practice.

  7. Application of color image processing and low-coherent optical computer tomography in evaluation of adhesive interfaces of dental restorations

    NASA Astrophysics Data System (ADS)

    Bessudnova, Nadezda O.; Shlyapnikova, Olga A.; Venig, Sergey B.; Genina, Elina A.; Sadovnikov, Alexandr V.

    2015-03-01

    Durability of bonded interfaces between dentin and a polymer material in resin-based composite restorations remains a clinical dentistry challenge. In the present study the evolution of bonded interfaces in biological active environment is estimated in vivo. A novel in vivo method of visual diagnostics that involves digital processing of color images of composite restorations and allows the evaluation of adhesive interface quality over time, has been developed and tested on a group of volunteers. However, the application of the method is limited to the analysis of superficial adhesive interfaces. Low-coherent optical computer tomography (OCT) has been tested as a powerful non-invasive tool for in vivo, in situ clinical diagnostics of adhesive interfaces over time. In the long-term perspective adhesive interface monitoring using standard methods of clinical diagnostics along with colour image analysis and OCT could make it possible to objectivise and prognosticate the clinical longevity of composite resin-based restorations with adhesive interfaces.

  8. Nickel-based (Ni-Cr and Ni-Cr-Be) alloys used in dental restorations may be a potential cause for immune-mediated hypersensitivity.

    PubMed

    Lu, Yin; Chen, Weiqing; Ke, Wei; Wu, Shaohua

    2009-11-01

    Although nickel-based (Ni-Cr and Ni-Cr-Be) alloy prothesis is widely used in orthodontics, its potential biologic hazards, hypersensitivity in particular, are still uncertain as yet. And only a few studies in vivo have considered the biocompatibility. However, several case reports show adverse effects of immunologic alterations, such as urticaria, respiratory disease, nickel contact dermatitis, microscopic hematuria and proteinuria, and even exacerbated to hepatocyte injury and renal injury. So nickel-based alloy used in dental restorations may be a potential cause for immune-mediated hypersensitivity. The metal surface would occur electrochemical corrosion as metal edge of porcelain-fused-to-nichrome crown exposed to oral cavity rich in electrolytes after restoration, and metal ion would release to oral cavity then come into contact with cells and tissues in the immediate environment, or be distributed throughout the body, mainly to the intestine canal. Once these ions are not biocompatible, the human system may be injured (toxicity and risk of sensitization) if they are absorbed in sufficient quantity. Thus, it is necessary to determine the long-term biocompatibility properties of nickel-based alloy, reduce sensitization, and grasp the information of individual differences in the appearance of adverse reactions in further research.

  9. [Studies on the pre-treatment of dental alloy for adhesive restorations. 4. Adhesive durability of adhesive resin to various dental alloys treated with composite plating].

    PubMed

    Kondo, Y; Yamashita, A; Suzuki, K; Omura, I; Yamauchi, J I

    1989-07-01

    In this study, the durability of adhesion between an adhesive resin (Panavia EX) and dental alloys (gold or Ni-Cr) were examined in regard to thermal cycling, immersion, either in water (70 degrees C or 100 degrees C) or in sodium chloride solutions (pH was 3, 7 and 9). An favourable adhesive strength, such as 450-500 kgf/cm2, was obtained even after 24 hours immersion in 37 degrees C water, when the surface pre-treatment of the alloy was done with either Sn- or composite (TMSAC/Sn or PVC/Sn)-plating. However, during the durability test, the adhesive strength has decreased to such on extent, that about 60% of early strength with Sn-plating and 80% with TMSAC/Sn composite plating. But, with PVC/Sn composite-plating, more than 90% of the early strength was maintained. In regard to the pH of the corrosive solution, no apparent difference was observed regarding the above mentioned adhesive characteristics.

  10. The all-ceramic, inlay supported fixed partial denture. Part 3. Experimental approach for validating the finite element analysis.

    PubMed

    Thompson, M C; Field, C J; Swain, M V

    2012-03-01

    In a previous study, the authors used a finite element analysis (FEA) to evaluate the stresses developed during the loading of an all-ceramic, inlay supported fixed partial denture and compared it with the more traditional full crown supported prosthesis. To date there has been little research into correlating the responses of the numerical model against physical mechanical tests; such validation analysis is crucial if the results from the FEA are to be confidently relied upon. This study reports on the experimental methods used to compare with the FEA and thereby to validate the predictive fracture behaviour of the numerical model. This study also outlines the methods for manufacture and testing of the ceramic structure along with observations of the fracture tests. In addition the procedure used for developing the FEA model for the test system is outlined.

  11. Restorative Treatment Thresholds for Occlusal Primary Caries by Dentists in “The Dental Practice-Based Research Network”

    PubMed Central

    Gordan, Valeria V; Bader, James D; Garvan, Cynthia W; Richman, Joshua S; Qvist, Vibeke; Fellows, Jeffrey L; Rindal, D. Brad; Gilbert, Gregg H

    2010-01-01

    Objectives (1) Quantify at which carious lesion depths dentists intervene surgically for cases of varying caries penetration and caries risk; (2) Identify characteristics that are associated with surgical intervention. Methods Dentists in a practice-based research network who reported doing at least some restorative dentistry were surveyed. Dentists were asked to indicate whether they would surgically intervene in a series of cases depicting occlusal caries. Each case included a photograph of an occlusal surface displaying typical characteristics of caries penetration, and a written description of a patient at a specific level of caries risk. Using logistic regression, we analyzed associations of surgical treatment with dentist and practice characteristics, and patient caries risk levels. Results 519 DPBRN practitioner-investigators responded, of whom 63% indicated that they would surgically restore lesions located on inner enamel surfaces, and 90% of lesions located in outer dentin surfaces in a low caries risk individual. Regarding individuals at high caries risk, 77% reported that they would surgically restore inner enamel lesions and 94% reported restoring lesions located on the outer dentin surface. Dentists who did not assess caries risk were more likely to intervene on dentin lesions (p=.004). Practitioner-investigators who were in private practice were significantly more likely to intervene surgically on enamel lesions, compared to dentists from large group practices (p<.001). Conclusion Most dentists chose to provide some treatment to lesions that were within the enamel surface. Decisions to intervene surgically in the caries process differ by caries lesion depth, patient caries risk, assessment of caries risk, type of practice model, and percent of patients who self-pay. PMID:20123876

  12. All-ceramic single-tooth implant reconstructions using modified zirconia abutments: a prospective randomized controlled clinical trial of the effect of pink veneering ceramic on the esthetic outcomes.

    PubMed

    Büchi, Dominik L E; Sailer, Irena; Fehmer, Vincent; Hämmerle, Christoph H F; Thoma, Daniel S

    2014-01-01

    The aim of this study was to test whether veneering of the submucosal part of zirconia abutments using pink veneering ceramic positively influences the color of the peri-implant mucosa. Single-tooth implants were restored with either white zirconia abutments (control group) or pink-veneered zirconia abutments and all-ceramic crowns. Esthetic outcome measurements included a spectrophotometric evaluation of the peri-implant mucosal color. Test and control groups induced a visible discoloration of the peri-implant mucosa after the insertion of the abutments and following cementation of the crowns compared to natural teeth. The calculated color differences were above the clinically visible threshold value and were more favorable for the control group, although not statistically significant. It is concluded that veneering of zirconia abutments with pink veneering ceramic failed to positively influence the esthetic outcome, mostly due to a decrease of the brightness compared with the control group.

  13. Objective assessment of the influence of the parental presence on the fear and behavior of anxious children during their first restorative dental visit

    PubMed Central

    Pani, Sharat C.; AlAnazi, Ghazi S.; AlBaragash, Abdulrahman; AlMosaihel, Mohammad

    2016-01-01

    Aims and Objectives: Parents play an important role in the dental behavior of a child patient. This study aimed to assess the effect of parental presence on the behavior of the child and objectively measure the behavior using pulse oximetry. Materials and Methods: The study was registered with the clinical trials registry of the National Institutes of Health (NCT02619981). The children were divided into three groups, those who had no accompanying parent, those accompanied by their fathers, and those accompanied by their mothers. The Venham anxiety and behavior scores were used for subjective measurements whereas the objective measurement of fear was done by measuring the heart rate using a portable pulse oximeter at six critical clinical situations. Statistical analysis was carried out using the Statistical Package for the Social Sciences version 21 (IBM corp. Armonk, NY, USA). Results: One hundred and twenty two children aged between 6 years and 8 years completed the study. Most of the children accompanied by fathers were males while most of the children accompanied by their mother were females. It was seen that females showed a higher mean heart rate than males at all steps. Children who had their parents outside the operatory exhibited lower anxiety and behavior scores than those whose parents were present; however, they showed a significantly higher pulse rate at all procedures. Boys had higher anxiety and behavior scores than girls, however, these differences were not statistically significant. Conclusion: The results of this study suggest that the presence of the parent in the operatory reduces the physiological manifestations of anxiety in children in their first restorative dental visit. PMID:27652248

  14. Esthetic and Clinical Performance of Implant-Supported All-Ceramic Crowns Made with Prefabricated or CAD/CAM Zirconia Abutments.

    PubMed

    Wittneben, J G; Gavric, J; Belser, U C; Bornstein, M M; Joda, T; Chappuis, V; Sailer, I; Brägger, U

    2017-02-01

    Patients' esthetic expectations are increasing, and the options of the prosthetic pathways are currently evolving. The objective of this randomized multicenter clinical trial was to assess and compare the esthetic outcome and clinical performance of anterior maxillary all-ceramic implant crowns (ICs) based either on prefabricated zirconia abutments veneered with pressed ceramics or on CAD/CAM zirconia abutments veneered with hand buildup technique. The null hypothesis was that there is no statistically significant difference between the 2 groups. Forty implants were inserted in sites 14 to 24 (FDI) in 40 patients in 2 centers, the Universities of Bern and Geneva, Switzerland. After final impression, 20 patients were randomized into group A, restored with a 1-piece screw-retained single crown made of a prefabricated zirconia abutment with pressed ceramic as the veneering material using the cut-back technique, or group B using an individualized CAD/CAM zirconia abutment (CARES abutment; Institut Straumann AG) with a hand buildup technique. At baseline, 6 mo, and 1 y clinical, esthetic and radiographic parameters were assessed. Group A exhibited 1 dropout patient and 1 failure, resulting in a survival rate of 94.7% after 1 y, in comparison to 100% for group B. No other complications occurred. Clinical parameters presented stable and healthy peri-implant soft tissues. Overall, no or only minimal crestal bone changes were observed with a mean DIB (distance from the implant shoulder to the first bone-to-implant contact) of -0.15 mm (group A) and 0.12 mm (group B) at 1 y. There were no significant differences at baseline, 6 mo, and 1 y for DIB values between the 2 groups. Pink esthetic score (PES) and white esthetic score (WES) values at all 3 examinations indicated stability over time for both groups and pleasing esthetic outcomes. Both implant-supported prosthetic pathways represent a valuable treatment option for the restoration of single ICs in the anterior maxilla

  15. A simplified impression technique for dental implants.

    PubMed

    Vogel, Robert E

    2002-03-01

    Dental implants have been considered an acceptable form of dental treatment since the early 1980s. A number of studies have been published describing impression techniques for dental implants. Many of the techniques described are so complex that they may seem daunting to the average restorative dentist. Most general practitioners do not wish to attempt to restore dental implants. This article describes a very simple, yet extremely accurate, technique for making impressions of dental implant fixtures.

  16. Minimally invasive prosthetic restoration of posterior tooth loss with resin-bonded, wing-retained, and inlay-retained fixed dental prostheses fabricated from monolithic zirconia: A clinical report of two patients.

    PubMed

    Bömicke, Wolfgang; Karl, Jochen; Rammelsberg, Peter

    2017-04-01

    The esthetics and biocompatibility of ceramic resin-bonded fixed dental prostheses (RBFDPs) are regarded as better than those of their metal ceramic counterparts. However, a high incidence of complications in the posterior arches of ceramic RBFDPs initiated a process of continuous and evolving design development. This clinical report describes 2 successful restorations of a missing posterior tooth with monolithic zirconia RBFDPs with 2 different retainer designs: retentively prepared adhesive wings and inlays.

  17. Erosive potential of commonly used beverages, medicated syrup, and their effects on dental enamel with and without restoration: An in vitro study

    PubMed Central

    Trivedi, Krishna; Bhaskar, Vijay; Ganesh, Mahadevan; Venkataraghavan, Karthik; Choudhary, Prashant; Shah, Shalin; Krishnan, Ramesh

    2015-01-01

    Aim: This study evaluates erosive potential of commonly used beverages, medicated syrup, and their effects on dental enamel with and without restoration in vitro. Materials and Methods: Test medias used in this study included carbonated beverage, noncarbonated beverage, high-energy sports drink medicated cough syrup, distilled water as the control. A total of 110 previously extracted human premolar teeth were selected for the study. Teeth were randomly divided into two groups. Test specimens were randomly distributed to five beverages groups and comprised 12 specimens per group. Surface roughness (profilometer) readings were performed at baseline and again, following immersion for 14 days (24 h/day). Microleakage was evaluated. The results obtained were analyzed for statistical significance using SPSS-PC package using the multiple factor ANOVA at a significance level of P < 0.05. Paired t-test, Friedman test ranks, and Wilcoxon signed ranks test. Results: For surface roughness high-energy sports drink and noncarbonated beverage showed the highly significant difference with P values of 0.000 and 0.000, respectively compared to other test media. For microleakage high-energy sports drink had significant difference in comparison to noncarbonated beverage (P = 0.002), medicated syrup (P = 0.000), and distilled water (P = 0.000). Conclusion: High-energy sports drink showed highest surface roughness value and microleakage score among all test media and thus greater erosive potential to enamel while medicated syrup showed least surface roughness value and microleakage among all test media. PMID:26538901

  18. Cementation of indirect restorations: an overview of resin cements.

    PubMed

    Stamatacos, Catherine; Simon, James F

    2013-01-01

    The process of ensuring proper retention, marginal seal, and durability of indirect restorations depends heavily on effective cementation. Careful consideration must be made when selecting an adhesive cement for a given application. This article provides information on resin cements that can guide clinicians in determining which type of cement is best suited to their clinical needs regarding cementation of indirect restorations. Emphasis is placed on successful cementation of all-ceramic restorations.

  19. Marginal and internal fit of all-ceramic crowns fabricated with two different CAD/CAM systems.

    PubMed

    Lee, Kyu-Bok; Park, Charn-Woon; Kim, Kyo-Han; Kwon, Tae-Yub

    2008-05-01

    This study evaluated the accuracy of marginal and internal fit between the all-ceramic crowns manufactured by a conventional double-layer computer-aided design/computer-aided manufacturing (CAD/CAM) system and a single-layer system. Ten standardized crowns were fabricated from each of these two systems: conventional double-layer CAD/CAM system (Procera) and a single-layer system (Cerec 3D). The copings and completed crowns were seated on the abutments by a special device that facilitated uniform loading, and the marginal discrepancies were measured. Internal gaps were also measured using a low-viscosity silicone material. Marginal discrepancies of Procera copings were significantly smaller than those of Procera crowns and Cerec 3D crowns (p < 0.05), but Procera crowns and Cerec 3D crowns did not differ significantly from each other (p > 0.05). On internal gaps, Cerec 3D crowns showed significantly larger internal gaps than Procera copings and crowns (p < 0.05). Within the limitations of this study, the single-layer system demonstrated acceptable marginal and internal fit.

  20. A comparative study of sliding wear of nonmetallic dental restorative materials with emphasis on micromechanical wear mechanisms.

    PubMed

    Dupriez, Nataliya Deyneka; von Koeckritz, Ann-Kristin; Kunzelmann, Karl-Heinz

    2015-05-01

    The purpose of this study is to investigate the in vitro tribological behavior of modern nonmetallic restorative materials. Specimen prepared of IPS e.max Press lithium disilicate glass ceramic, IPS Empress Esthetic leucite-reinforced glass ceramic, Everest ZS Blanks yttria-stabilized zirconia and Lava Ultimate composite were subjected to wear using a wear machine designed to simulate occlusal loads. The wear of the investigated materials and antagonists were evaluated by a three-dimensional surface scanner. The quantitative wear test results were used to compare and rank the materials. Specimens were divided into two groups with steatite and alumina antagonists. For each antagonist material an analysis of variance was applied. As a post hoc test of the significant differences, Tukey's honest significant difference test was used. With steatite antagonist: wear of zirconia < wear of leucite-reinforced ceramic < wear of lithium disilicate ceramic < wear of Lava Ultimate composite. No significant wear difference was found for steatite antagonist. The wear of IPS e.max Press and Lava Ultimate against hard alumina was found to be twice lower as compared to their wear when opposing to steatite. The differences were associated with materials mechanical properties (hardness and fracture toughness) and with materials microstructure. Wear mechanisms are discussed.

  1. Critical appraisal: dental amalgam update--part II: biological effects.

    PubMed

    Wahl, Michael J; Swift, Edward J

    2013-12-01

    Dental amalgam restorations have been controversial for over 150 years. In Part I of this Critical Appraisal, the clinical efficacy of dental amalgam was updated. Here in Part II, the biological effects of dental amalgam are addressed.

  2. Effects of different concentrations of carbamide peroxide and bleaching periods on the roughness of dental ceramics.

    PubMed

    Ourique, Sérgio Augusto Morey; Arrais, César Augusto Galvão; Cassoni, Alessandra; Ota-Tsuzuki, Cláudia; Rodrigues, José Augusto

    2011-01-01

    The wide use of dental bleaching treatment has brought concern about the possible effects of hydrogen peroxide on dental tissue and restorative materials. The objective of this study was to evaluate in vitro the effect of nightguard bleaching on the surface roughness of dental ceramics after different periods of bleaching treatment. Fifteen specimens of 5 × 3 × 1 mm were created with three dental ceramics following the manufacturers' instructions: IPS Classic (Ivoclar-Vivadent); IPS d.Sign (Ivoclar-Vivadent); and VMK-95 (Vita). A profilometer was used to evaluate baseline surface roughness (Ra values) of all ceramics by five parallel measurements with five 0.25 mm cut off (Λc) at 0.1 mm/s. Afterwards, all specimens were submitted to 6-h daily bleaching treatments with 10% or 16% carbamide peroxide (Whiteness- FGM) for 21 days, while control groups from each ceramic system were stored in artificial saliva. The surface roughness of all groups was evaluated after 18 h, 42 h, 84 h, and 126 h of bleaching treatment. The surface roughness of each specimen (n = 5) was based on the mean value of five parallel measurements in each time and all data were submitted to two-way repeated measures ANOVA and Tukey's post-hoc test (α = 0.05). No significant differences in ceramic surface roughness were observed between untreated and bleached ceramic surfaces, regardless of bleaching intervals or bleaching treatments. This study provided evidence that at-home bleaching systems do not cause detrimental effects on surface roughness of dental ceramics.

  3. 21 CFR 872.3700 - Dental mercury.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Dental mercury. 872.3700 Section 872.3700 Food and... DENTAL DEVICES Prosthetic Devices § 872.3700 Dental mercury. (a) Identification. Dental mercury is a device composed of mercury intended for use as a component of amalgam alloy in the restoration of...

  4. Effects of surface-conditioning methods on shear bond strength of brackets bonded to different all-ceramic materials.

    PubMed

    Saraç, Y Şinasi; Külünk, Tolga; Elekdağ-Türk, Selma; Saraç, Duygu; Türk, Tamer

    2011-12-01

    The aims of this study were to investigate the effects of two surface-conditioning methods on the shear bond strength (SBS) of metal brackets bonded to three different all-ceramic materials, and to evaluate the mode of failure after debonding. Twenty feldspathic, 20 fluoro-apatite, and 20 leucite-reinforced ceramic specimens were examined following two surface-conditioning methods: air-particle abrasion (APA) with 25 μm Al(2)O(3) and silica coating with 30 μm Al(2)O(3) particles modified by silica. After silane application, metal brackets were bonded with light cure composite and then stored in distilled water for 1 week and thermocycled (×1000 at 5-55°C for 30 seconds). The SBS of the brackets was measured on a universal testing machine. The ceramic surfaces were examined with a stereomicroscope to determine the amount of composite resin remaining using the adhesive remnant index. Two-way analysis of variance, Tukey's multiple comparison test, and Weibull analysis were used for evaluation of SBS. The lowest SBS was with APA for the fluoro-apatite ceramic (11.82 MPa), which was not significantly different from APA for the feldspathic ceramic (13.58 MPa). The SBS for the fluoro-apatite ceramic was significantly lower than that of leucite-reinforced ceramic with APA (14.82 MPa). The highest SBS value was obtained with silica coating of the leucite-reinforced ceramic (24.17 MPa), but this was not significantly different from the SBS for feldspathic and fluoro-apatite ceramic (23.51 and 22.18 MPa, respectively). The SBS values with silica coating showed significant differences from those of APA. For all samples, the adhesive failures were between the ceramic and composite resin. No ceramic fractures or cracks were observed. Chairside tribochemical silica coating significantly increased the mean bond strength values.

  5. Full-mouth rehabilitation with monolithic CAD/CAM-fabricated hybrid and all-ceramic materials: A case report and 3-year follow up.

    PubMed

    Selz, Christian F; Vuck, Alexander; Guess, Petra C

    2016-02-01

    Esthetic full-mouth rehabilitation represents a great challenge for clinicians and dental technicians. Computer-aided design/ computer-assisted manufacture (CAD/CAM) technology and novel ceramic materials in combination with adhesive cementation provide a reliable, predictable, and economic workflow. Polychromatic feldspathic CAD/CAM ceramics that are specifically designed for anterior indications result in superior esthetics, whereas novel CAD/CAM hybrid ceramics provide sufficient fracture resistance and adsorption of the occlusal load in posterior areas. Screw-retained monolithic CAD/CAM lithium disilicate crowns (ie, hybrid abutment crowns) represent a reliable and time- and cost-efficient prosthetic implant solution. This case report details a CAD/CAM approach to the full-arch rehabilitation of a 65-year-old patient with toothand implant-supported restorations and provides an overview of the applied CAD/CAM materials and the utilized chairside intraoral scanner. The esthetics, functional occlusion, and gingival and peri-implant tissues remained stable over a follow-up period of 3 years. No signs of fractures within the restorations were observed.

  6. Comparison of the static loading capacity of all-ceramic bridge frameworks in posterior teeth using three hard core materials.

    PubMed

    Dornhofer, R; Arnetzl, G V; Koller, M; Arnetzl, G

    2007-10-01

    In this in vitro investigation, we studied the static strength of three-unit all-ceramic bridge frameworks with rigid positioning of the abutments. The materials used were Vita InCeram Alumina, Vita InCeram Zirkonia, and zirconium oxide (Vita InCeram (X YZ Cubes for Cerec). A finite element calculation was performed for numerical comparison of the load-bearing capacity of two main normal tensions. The purpose of the investigation was to design a framework made from hard core material, that offers the greatest possible resistance in static fracture loading tests. In a model, the 2nd maxillary right premolar and 2nd maxillary right molar served as bridge abutments and were provided with a chamfer preparation. On this base, two different bridge frameworks were constructed using CAD/CAM technology after an impression had been taken. One bridge connector was designed heart-shaped, with contact to the gingiva, while the other was designed as a "free-connector" at a distance of 1.2 mm from the gingiva. In this framework design, the radius in the cervical connector area is larger. We were uncertain as to whether it would be possible to further increase the strength of the ceramic material by the use of the differently designed pontic, independent of the hard core ceramic used. The least fracture strength was registered for the "heart-shaped connector" constructed from InCeram Alumina, with a mean fracture load of about 1089 Newton (N). The connector designed as a "free connector", made from the same material, was stronger by 10%. With the materials InCeram Zirkonia and zirconium dioxide as well, the "free-connector" design achieved a 10% higher breakage limit than the heart-shaped design. InCeram Zirkonia was 25% more stable in the static load tests than InCeram Alumina. Zirconium dioxide demonstrated a 2.3-fold greater strength than InCeram Alumina, while the free-connector design showed the greatest mean static loading capacity of 2808 N.

  7. THERMAL RESIDUAL STRESSES IN BILAYERED, TRILAYERED AND GRADED DENTAL CERAMICS

    PubMed Central

    Fabris, Douglas; Souza, Júlio C.M.; Silva, Filipe S.; Fredel, Márcio; Mesquita-Guimarães, Joana; Zhang, Yu; Henriques, Bruno

    2017-01-01

    Layered ceramic systems are usually hit by residual thermal stresses created during cooling from high processing temperature. The purpose of this study was to determine the thermal residual stresses at different ceramic multi-layered systems and evaluate their influence on the bending stress distribution. Finite elements method was used to evaluate the residual stresses in zirconia-porcelain and alumina-porcelain multi-layered discs and to simulate the ‘piston-on-ring’ test. Temperature-dependent material properties were used. Three different multi-layered designs were simulated: a conventional bilayered design; a trilayered design, with an intermediate composite layer with constant composition; and a graded design, with an intermediate layer with gradation of properties. Parameters such as the interlayer thickness and composition profiles were varied in the study. Alumina-porcelain discs present smaller residual stress than the zirconia-porcelain discs, regardless of the type of design. The homogeneous interlayer can yield a reduction of ~40% in thermal stress relative to bilayered systems. Thinner interlayers favoured the formation of lower thermal stresses. The graded discs showed the lowest thermal stresses for a gradation profile given by power law function with p=2. The bending stresses were significantly affected by the thermal stresses in the discs. The risk of failure for all-ceramic dental restorative systems can be significantly reduced by using trilayered systems (homogenous or graded interlayer) with the proper design. PMID:28163345

  8. Dental Amalgam

    MedlinePlus

    ... Products and Medical Procedures Dental Devices Dental Amalgam Dental Amalgam Share Tweet Linkedin Pin it More sharing options Linkedin Pin it Email Print Dental amalgam is a dental filling material which is ...

  9. Comparative study of flexural strength test methods on CAD/CAM Y-TZP dental ceramics

    PubMed Central

    Xu, Yongxiang; Han, Jianmin; Lin, Hong; An, Linan

    2015-01-01

    Clinically, fractures are the main cause of computer-aided design and computer-aided manufacturing (CAD/CAM) 3 mol%-yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) all-ceramic dental restorations failure because of repetitive occlusal loading. The goal of this work is to study the effect of test methods and specimen’s size on the flexural strength of five ceramic products. Both bi-axial flexure test (BI) and uni-axial flexure tests (UNI), including three-point flexure test (3PF) and four-point flexure test (4PF), are used in this study. For all five products, the flexural strength is as follows: BI > 3PF > 4PF. Furthermore, specimens with smaller size (3PF-s) have higher values than the bigger ones (3PF). The difference between BI and UNI resulted from the edge flaws in ceramic specimens. The relationship between different UNI (including 3PF-s, 3PF and 4PF) can be explained according to Weibull statistical fracture theory. BI is recommended to evaluate the flexural strength of CAD/CAM Y-TZP dental ceramics. PMID:26816646

  10. Dental amalgam: An update

    PubMed Central

    Bharti, Ramesh; Wadhwani, Kulvinder Kaur; Tikku, Aseem Prakash; Chandra, Anil

    2010-01-01

    Dental amalgam has served as an excellent and versatile restorative material for many years, despite periods of controversy. The authors review its history, summarize the evidence with regard to its performance and offer predictions for the future of this material. The PubMed database was used initially; the reference list for dental amalgam featured 8641 articles and 13 publications dealing with recent advances in dental amalgam. A forward search was undertaken on selected articles and using some author names. For the present, amalgam should remain the material of choice for economic direct restoration of posterior teeth. When esthetic concerns are paramount, tooth-colored materials, placed meticulously, can provide an acceptable alternative. All alternative restorative materials and procedures, however, have certain limitations. PMID:21217947

  11. Prospective clinical study of press-ceramic overlap and full veneer restorations: 7-year results.

    PubMed

    Guess, Petra C; Selz, Christian F; Voulgarakis, Apostolos; Stampf, Susanne; Stappert, Christian F J

    2014-01-01

    The aim of this prospective clinical study was to investigate the long-term performance of all-ceramic veneers with overlap (OV) and full veneer (FV) preparation designs. Twenty-five patients were restored using 42 OV restorations (incisal/palatal butt-joint margin) and 24 FV restorations (palatal rounded shoulder margin). All restorations were leucite-reinforced glass-ceramic anterior veneers. The 7-year Kaplan-Meier survival rate was 100% for FV restorations and 97.6% for OV restorations. The all-ceramic veneers revealed significant deterioration over time according to United States Public Health Service criteria, irrespective of the preparation design. Based on the 7-year results of this study, both preparation designs can be considered reliable treatment options for anterior teeth with extended deficits.

  12. Esthetic Rehabilitation of Anterior Teeth with Copy-Milled Restorations: A Report of Two Cases

    PubMed Central

    Jain, Chandan; Mutneja, Parul; Verma, Mahesh

    2017-01-01

    Digitalization has become part and parcel of contemporary prosthodontics with the probability of most of the procedures being based on the digital techniques in the near future. This digital revolution started in the latter half of the 20th century by converting analog objects/signals into digital bits and bytes. Recent developments in all-ceramic materials and systems of computer-aided designing and computer-aided manufacturing (CAD/CAM), copy milling, and so forth offer excellent esthetics and superb biocompatibility. Copy milling system for ceramics enables milling of the zirconia cores of all-ceramic restorations precisely and also if this system is properly used the procedure for fabricating all-ceramic restorations can be substantially simplified. This case report presents fabrication of all-ceramic Maryland Bridge and post-core with a copy milling system for esthetics and preservation of integrity of tooth. For both of the patients, the use of biologic, all-ceramic, copy-milled restorations resulted in clinical success and recovered function and esthetics. PMID:28326203

  13. Feline dental disease.

    PubMed

    Frost, P; Williams, C A

    1986-09-01

    Periodontal disease and chronic gingivitis/stomatitis are the most common feline dental diseases. With routine dental care and increased emphasis on home oral hygiene, these diseases can be controlled. Cats can be seen with a number of other dental disorders, and improved treatment methods such as restorations of early subgingival resorptive lesions, endodontic therapy, and orthodontic therapy can be performed successfully. More study and research are necessary about the gingivitis/stomatitis syndrome and subgingival resorptive lesions so that improved prevention and treatment recommendations can be made.

  14. Greater Utilization of Dental Technicians, II. Report of Clinical Tests.

    ERIC Educational Resources Information Center

    Ludwick, William E.; And Others

    Following specialized training in which naval dental assistants were taught to insert restorations in cavities prepared by dental officers, clinical tests were applied to determine how much more a dental officer can accomplish when he delegates certain procedures to specially trained assistants, to evaluate the quality of the restorations, and to…

  15. Electronic dental anesthesia in a patient with suspected allergy to local anesthetics: report of case.

    PubMed

    Malamed, S F; Quinn, C L

    1988-01-01

    A 56-year-old patient with alleged allergy to local anesthetics required restorative dental treatment. Electronic dental anesthesia was used successfully, in lieu of injectable local anesthetics, to manage intraoperative pain associated with the restoration of vital mandibular teeth.

  16. A bioactive dental luting cement--its retentive properties and 3-year clinical findings.

    PubMed

    Jefferies, Steven R; Pameijer, Cornelis H; Appleby, David C; Boston, Daniel; Lööf, Jesper

    2013-02-01

    -year recall. After periodic recalls up to 3 years, Ceramir C&B thus far has performed quite favorably as a luting agent for permanent cementation of permanent restorations. In-vitro crown-coping retention studies were also conducted using this cement and various control cementation materials. Mean laboratory retentive forces measured for Ceramir C&B were comparable to other currently available luting agents for both metal and all-ceramic indirect restorative materials.

  17. Influence of core thickness and artificial aging on the biaxial flexural strength of different all-ceramic materials: An in-vitro study.

    PubMed

    Dikicier, Sibel; Ayyildiz, Simel; Ozen, Julide; Sipahi, Cumhur

    2017-02-11

    The purpose of this study was to investigate the flexural strength of all-ceramics with varying core thicknesses submitted to aging. In-Ceram Alumina (IC), IPS e.max Press (EM) and Katana (K) (n=40), were selected. Each group contained two core groups based on the core thickness as follows: IC/0.5, IC/0.8, EM/0.5, EM/0.8, K/0.5 and K/0.8 mm in thickness (n=20 each). Ten specimens from each group were subjected to aging and all specimens were tested for strength in a testing machine either with or without being subjected aging. The mean strength of the K were higher (873.05 MPa) than that of the IC (548.28 MPa) and EM (374.32 MPa) regardless of core thickness. Strength values increased with increasing core thickness for all IC, EM and K regardless of aging. Results of this study concluded that strength was not significantly affected by aging. Different core thicknesses affected strength of the all-ceramic materials tested (p<0.05).

  18. A 3-year follow-up study of all-ceramic single and multiple crowns performed in a private practice: a prospective case series

    PubMed Central

    Tartaglia, Gianluca M.; Sidoti, Ernesto; Sforza, Chiarella

    2011-01-01

    OBJECTIVES: Zirconia-based prostheses are commonly used for aesthetic crown and fixed restorations, although follow-up data are limited, especially for implant-supported crowns. The aim of this study was to evaluate the three-year clinical results of the installation of 463 zirconia core crowns by a general dental private practice. METHODS: This study followed 142 patients (69 men and 73 women; aged 28-82 years) who had received 248 single crowns (202 tooth-supported, 36 implant-supported) and 225 multiple units of up to six elements (81 tooth-supported, 144 implant-supported). Clinical events, including fracture and loss of retention, secondary caries, and marginal integrity, were recorded. The overall failure rate was computed for the fractured and lost prostheses. Aesthetic, functional, and biological properties were rated, and patient satisfaction was investigated. RESULTS: During the three-year follow-up period, four patients were lost from the study (18 crowns, 4% of the total crowns). Three of the zirconia prostheses suffered fractures in more than three units (11 crowns; one- vs. three-year follow-up, p<0.05, Wilcoxon signed-rank test), and the cumulative prosthesis survival rate was 98.2%. Twelve units lost retention and were re-cemented, and no secondary caries of the abutment teeth were reported. The aesthetic, functional, and biological properties were generally well-rated, and there were no differences between tooth- and implant-supported crowns. The lowest scores were given regarding the anatomical form of the crowns, as some minor chipping was reported. Relatively low scores were also given for the periodontal response and the adjacent mucosa. Overall, patient satisfaction was high. CONCLUSIONS: At the three-year follow-up, the zirconia-core crowns appeared to be an effective clinical solution as they had favorable aesthetic and functional properties. Only the marginal fit of the prostheses should be improved upon. PMID:22189731

  19. The quality of impressions for crowns and bridges: an assessment of the work received at three commercial dental laboratories. assessing qualities of impressions that may lead to occlusal discrepancies with indirect restorations.

    PubMed

    Storey, D; Coward, T J

    2014-03-01

    There are few published studies that directly assess the quality of impressions for crowns and bridges in the UK. This paper considers aspects of impression quality with particular attention to factors causing potential occlusal discrepancies in the final restoration. To this end three dental laboratories were visited over a 3-month period. All impressions for conventional crown and bridgework that arrived on the days of the visits were examined and assessed against criteria defined on a custom-designed assessment form. A total of 206 impression cases were considered in this study. Flexible impression trays were used for 65% of working impressions. Their use was more common for NHS work than for private work. 31.9% of all alginate impressions examined were not adequately fixed to the tray. Visible contamination of impressions was not uncommon.

  20. Class II Resin Composites: Restorative Options.

    PubMed

    Patel, Minesh; Mehta, Shamir B; Banerji, Subir

    2015-10-01

    Tooth-coloured, resin composite restorations are amongst the most frequently prescribed forms of dental restoration to manage defects in posterior teeth. The attainment of a desirable outcome when placing posterior resin composite restorations requires the clinician to have a good understanding of the benefits (as well as the limitations) posed by this material, together with a sound knowledge of placement technique. Numerous protocols and materials have evolved to assist the dental operator with this type of demanding posterior restoration. With the use of case examples, four techniques available are reported here. CPD/Clinical Relevance: This article explores varying techniques for the restoration of Class II cavities using resin composite.

  1. Maximizing esthetic results on zirconia-based restorations.

    PubMed

    Chang, Yi-Yuan

    2011-01-01

    With a flexural strength of approximately 900-1,100 MPa, zirconium oxide is one of the toughest all-ceramic materials available in dentistry.1 It can be used to fabricate both single-unit and long-span bridge frameworks. A moderate level of translucency makes it suitable for esthetically demanding clinical cases, such as restoring maxillary anterior teeth. A variety of well-designed porcelain veneering systems allow technicians to apply their artistic skills to create natural, lifelike restorations. A good balance of strength, precision, and translucency allows zirconia-based restorations to accommodate a variety of clinical situations.

  2. [The application of universal adhesives in dental bonding].

    PubMed

    Guo, Jingmei; Lei, Wenlong; Yang, Hongye; Huang, Cui

    2016-03-01

    The bonding restoration has become an important clinical technique for the development of dental bonding technology. Because of its easy operation and the maximum preservation of tooth tissues, bonding repair is widely used in dental restoration. The recent multi-mode universal adhesives have brought new progress in dental bonding restoration. In this article the universal adhesives were reviewed according to its definition, development, improvement, application features and possible problems.

  3. Restoration of a modified solid abutment of the ITI dental implant system: one of the most unique systems in implant dentistry.

    PubMed

    Charters, R T

    2001-01-01

    Although this system requires the use of some different impression techniques, it provides the dentist and technician a unique and simple method to restore a missing tooth with an implant-retained crown. The Straumann ITI impression coping and analog system allow the fabrication of a hybrid die for predictable results.

  4. Marginal fit of all-ceramic crowns fabricated using two extraoral CAD/CAM systems in comparison with the conventional technique

    PubMed Central

    Alqahtani, Fawaz

    2017-01-01

    Objective The purpose of this study was to determine the effect of two extraoral computer-aided design (CAD) and computer-aided manufacturing (CAM) systems, in comparison with conventional techniques, on the marginal fit of monolithic CAD/CAM lithium disilicate ceramic crowns. Study design This is an in vitro interventional study. Place and duration of study The study was carried out at the Department of Prosthodontics, School of Dentistry, Prince Sattam Bin Abdul-Aziz University, Saudi Arabia, from December 2015 to April 2016. Methodology A marginal gap of 60 lithium disilicate crowns was evaluated by scanning electron microscopy. In total, 20 pressable lithium disilicate (IPS e.max Press [Ivoclar Vivadent]) ceramic crowns were fabricated using the conventional lost-wax technique as a control group. The experimental all-ceramic crowns were produced based on a scan stone model and milled using two extraoral CAD/CAM systems: the Cerec group was fabricated using the Cerec CAD/CAM system, and the Trios group was fabricated using Trios CAD and milled using Wieland Zenotec CAM. One-way analysis of variance (ANOVA) and the Scheffe post hoc test were used for statistical comparison of the groups (α=0.05). Results The mean (±standard deviation) of the marginal gap of each group was as follows: the Control group was 91.15 (±15.35) µm, the Cerec group was 111.07 (±6.33) µm, and the Trios group was 60.17 (±11.09) µm. One-way ANOVA and the Scheffe post hoc test showed a statistically significant difference in the marginal gap between all groups. Conclusion It can be concluded from the current study that all-ceramic crowns, fabricated using the CAD/CAM system, show a marginal accuracy that is acceptable in clinical environments. The Trios CAD group displayed the smallest marginal gap. PMID:28352204

  5. Improved single- and multi-contact life-time testing of dental restorative materials using key characteristics of the human masticatory system and a force/position-controlled robotic dental wear simulator.

    PubMed

    Raabe, D; Harrison, A; Ireland, A; Alemzadeh, K; Sandy, J; Dogramadzi, S; Melhuish, C; Burgess, S

    2012-03-01

    This paper presents a new in vitro wear simulator based on spatial parallel kinematics and a biologically inspired implicit force/position hybrid controller to replicate chewing movements and dental wear formations on dental components, such as crowns, bridges or a full set of teeth. The human mandible, guided by passive structures such as posterior teeth and the two temporomandibular joints, moves with up to 6 degrees of freedom (DOF) in Cartesian space. The currently available wear simulators lack the ability to perform these chewing movements. In many cases, their lack of sufficient DOF enables them only to replicate the sliding motion of a single occlusal contact point by neglecting rotational movements and the motion along one Cartesian axis. The motion and forces of more than one occlusal contact points cannot accurately be replicated by these instruments. Furthermore, the majority of wear simulators are unable to control simultaneously the main wear-affecting parameters, considering abrasive mechanical wear, which are the occlusal sliding motion and bite forces in the constraint contact phase of the human chewing cycle. It has been shown that such discrepancies between the true in vivo and the simulated in vitro condition influence the outcome and the quality of wear studies. This can be improved by implementing biological features of the human masticatory system such as tooth compliance realized through the passive action of the periodontal ligament and active bite force control realized though the central nervous system using feedback from periodontal preceptors. The simulator described in this paper can be used for single- and multi-occlusal contact testing due to its kinematics and ability to exactly replicate human translational and rotational mandibular movements with up to 6 DOF without neglecting movements along or around the three Cartesian axes. Recorded human mandibular motion and occlusal force data are the reference inputs of the simulator

  6. Surface texture measurement for dental wear applications

    NASA Astrophysics Data System (ADS)

    Austin, R. S.; Mullen, F.; Bartlett, D. W.

    2015-06-01

    The application of surface topography measurement and characterization within dental materials science is highly active and rapidly developing, in line with many modern industries. Surface measurement and structuring is used extensively within oral and dental science to optimize the optical, tribological and biological performance of natural and biomimetic dental materials. Although there has historically been little standardization in the use and reporting of surface metrology instrumentation and software, the dental industry is beginning to adopt modern areal measurement and characterization techniques, especially as the dental industry is increasingly adopting digital impressioning techniques in order to leverage CAD/CAM technologies for the design and construction of dental restorations. As dental treatment becomes increasingly digitized and reliant on advanced technologies such as dental implants, wider adoption of standardized surface topography and characterization techniques will become evermore essential. The dental research community welcomes the advances that are being made in surface topography measurement science towards realizing this ultimate goal.

  7. Dental therapists in general dental practices: an economic evaluation.

    PubMed

    Beazoglou, Tryfon J; Lazar, Vickie F; Guay, Albert H; Heffley, Dennis R; Bailit, Howard L

    2012-08-01

    Dental access disparities are well documented and have been recognized as a national problem. Their major cause is the lack of reasonable Medicaid reimbursement rates for the underserved. Specifically, Medicaid reimbursement rates for children average 40 percent below market rates. In addition, most state Medicaid programs do not cover adults. To address these issues, advocates of better oral health for the underserved are considering support for a new allied provider--a dental therapist--capable of providing services at a lower cost per service and in low-income and rural areas. Using a standard economic analysis, this study estimated the potential cost, price, utilization, and dentist's income effects of dental therapists employed in general dental practices. The analysis is based on national general dental practice data and the broadest scope of responsibility for dental therapists that their advocates have advanced, including the ability to provide restorations and extractions to adults and children, training for three years, and minimum supervision. Assuming dental therapists provide restorative, extraction, and pulpal services to patients of all ages and dental hygienists continue to deliver all hygiene services, the mean reduction in a general practice costs ranges between 1.57 and 2.36 percent. For dental therapists treating children only, the range is 0.31 to 0.47 percent. The effects on price and utilization are even smaller. In addition, the effects on most dentists' gross income, hours of work, and net income are negative. The estimated economic impact of dental therapists in the United States on private dental practice is very limited; therefore, the demand for dental therapists by private practices also would probably be very limited.

  8. Dental Procedures.

    PubMed

    Ramponi, Denise R

    2016-01-01

    Dental problems are a common complaint in emergency departments in the United States. There are a wide variety of dental issues addressed in emergency department visits such as dental caries, loose teeth, dental trauma, gingival infections, and dry socket syndrome. Review of the most common dental blocks and dental procedures will allow the practitioner the opportunity to make the patient more comfortable and reduce the amount of analgesia the patient will need upon discharge. Familiarity with the dental equipment, tooth, and mouth anatomy will help prepare the practitioner for to perform these dental procedures.

  9. Novel Osteogenic Ti-6Al-4V Device For Restoration Of Dental Function In Patients With Large Bone Deficiencies: Design, Development And Implementation.

    PubMed

    Cohen, D J; Cheng, A; Kahn, A; Aviram, M; Whitehead, A J; Hyzy, S L; Clohessy, R M; Boyan, B D; Schwartz, Z

    2016-02-08

    Custom devices supporting bone regeneration and implant placement are needed for edentulous patients with large mandibular deficiencies where endosteal implantation is not possible. We developed a novel subperiosteal titanium-aluminum-vanadium bone onlay device produced by additive manufacturing (AM) and post-fabrication osteogenic micro-/nano-scale surface texture modification. Human osteoblasts produced osteogenic and angiogenic factors when grown on laser-sintered nano-/micro-textured surfaces compared to smooth surfaces. Surface-processed constructs caused higher bone-to-implant contact, vertical bone growth into disk pores (microCT and histomorphometry), and mechanical pull-out force at 5 and 10 w on rat calvaria compared to non surface-modified constructs, even when pre-treating the bone to stimulate osteogenesis. Surface-modified wrap-implants placed around rabbit tibias osseointegrated by 6 w. Finally, patient-specific constructs designed to support dental implants produced via AM and surface-processing were implanted on edentulous mandibular bone. 3 and 8 month post-operative images showed new bone formation and osseointegration of the device and indicated stability of the dental implants.

  10. Novel Osteogenic Ti-6Al-4V Device For Restoration Of Dental Function In Patients With Large Bone Deficiencies: Design, Development And Implementation

    PubMed Central

    Cohen, D. J.; Cheng, A.; Kahn, A.; Aviram, M.; Whitehead, A. J.; Hyzy, S. L.; Clohessy, R. M.; Boyan, B. D.; Schwartz, Z.

    2016-01-01

    Custom devices supporting bone regeneration and implant placement are needed for edentulous patients with large mandibular deficiencies where endosteal implantation is not possible. We developed a novel subperiosteal titanium-aluminum-vanadium bone onlay device produced by additive manufacturing (AM) and post-fabrication osteogenic micro-/nano-scale surface texture modification. Human osteoblasts produced osteogenic and angiogenic factors when grown on laser-sintered nano-/micro-textured surfaces compared to smooth surfaces. Surface-processed constructs caused higher bone-to-implant contact, vertical bone growth into disk pores (microCT and histomorphometry), and mechanical pull-out force at 5 and 10 w on rat calvaria compared to non surface-modified constructs, even when pre-treating the bone to stimulate osteogenesis. Surface-modified wrap-implants placed around rabbit tibias osseointegrated by 6 w. Finally, patient-specific constructs designed to support dental implants produced via AM and surface-processing were implanted on edentulous mandibular bone. 3 and 8 month post-operative images showed new bone formation and osseointegration of the device and indicated stability of the dental implants. PMID:26854193

  11. Proper selection of contemporary dental cements.

    PubMed

    Yu, Hao; Zheng, Ming; Chen, Run; Cheng, Hui

    2014-03-01

    Today proper selection of dental cements is a key factor to achieve a successful restoration and will greatly increase the chances of long-term success of the restoration. In recent years, many newly formulated dental cements have been developed with the claim of better performance compared to the traditional materials. Unfortunately, selection of suitable dental cement for a specific clinical application has become increasingly complicated, even for the most experienced dentists. The purpose of this article is to review the currently existing dental cements and to help the dentists choose the most suitable materials for clinical applications.

  12. Expanded functions for dental auxiliaries education in Tennessee.

    PubMed

    Robbins, Morris L

    2011-01-01

    Access to care continues to be an overriding issue in dentistry. The development of new categories of dental auxiliaries, such as mid-level providers, is a matter of concern to many states and the dental profession. Tennessee has an EFDA educational program for dental auxiliaries taught by dental school educators who have trained more than 300 auxiliary personnel in restorative and prosthetic dentistry. Graduates of this educational program have helped keep Tennessee's dentists well ahead of any increased demand for dental care.

  13. Findings of a Four-Year Randomized Controlled Clinical Trial Comparing Two-Piece and One-Piece Zirconia Abutments Supporting Single Prosthetic Restorations in Maxillary Anterior Region

    PubMed Central

    Paolantoni, Guerino; Marenzi, Gaetano; Blasi, Andrea; Mignogna, Jolanda; Sammartino, Gilberto

    2016-01-01

    The purpose of this randomized controlled study is to investigate the clinical results obtained over four years and incidence of complications associated with one- versus two-piece custom made zirconia anchorages, in single tooth implant-supported restorations of the maxillary anterior region. Sixty-five patients, with a total of 74 missing maxillary teeth, were selected in the period from February 2007 to July 2010. Two different ways of custom made zirconia abutment and final prosthetic restoration were evaluated: a standard zirconia abutment associated with a pressed layer of lithium disilicate with an all-ceramic cemented restoration versus one-piece restoration with the facing porcelain fired and pressed straight to the custom made zirconia abutment. In 29 cases, the restoration consisted of an all-ceramic restoration for cementation (two pieces); in 45 cases the restoration was a screw-retained restoration (one piece). Three all-ceramic restorations broke during the observation time. Two one-piece restorations fractured after 26 months. At follow-up examination there were no significant differences between one-piece and two-piece groups regarding the PI, BI, and MBL. Awaiting studies with longer follow-up times, a careful conclusion is that zirconia anchorages for single-implant restorations seem to demonstrate good short-term technical and biological results. PMID:27027093

  14. Findings of a Four-Year Randomized Controlled Clinical Trial Comparing Two-Piece and One-Piece Zirconia Abutments Supporting Single Prosthetic Restorations in Maxillary Anterior Region.

    PubMed

    Paolantoni, Guerino; Marenzi, Gaetano; Blasi, Andrea; Mignogna, Jolanda; Sammartino, Gilberto

    2016-01-01

    The purpose of this randomized controlled study is to investigate the clinical results obtained over four years and incidence of complications associated with one- versus two-piece custom made zirconia anchorages, in single tooth implant-supported restorations of the maxillary anterior region. Sixty-five patients, with a total of 74 missing maxillary teeth, were selected in the period from February 2007 to July 2010. Two different ways of custom made zirconia abutment and final prosthetic restoration were evaluated: a standard zirconia abutment associated with a pressed layer of lithium disilicate with an all-ceramic cemented restoration versus one-piece restoration with the facing porcelain fired and pressed straight to the custom made zirconia abutment. In 29 cases, the restoration consisted of an all-ceramic restoration for cementation (two pieces); in 45 cases the restoration was a screw-retained restoration (one piece). Three all-ceramic restorations broke during the observation time. Two one-piece restorations fractured after 26 months. At follow-up examination there were no significant differences between one-piece and two-piece groups regarding the PI, BI, and MBL. Awaiting studies with longer follow-up times, a careful conclusion is that zirconia anchorages for single-implant restorations seem to demonstrate good short-term technical and biological results.

  15. Immediate Placement and Occlusal Loading of Single-Tooth Restorations on Partially Threaded, Titanium-Tantalum Combined Dental Implants: 1-Year Results.

    PubMed

    Peron, Cristian; Romanos, Georgios

    2016-01-01

    Single nonrestorable teeth were atraumatically extracted and hybrid titanium implants with tantalum-based midsections (TM) were placed in fresh extraction sockets. Provisional acrylic crowns were delivered (in occlusion) immediately after surgery. Occlusal contacts were present in the maximal intercuspation but not in the lateral movements of the mandible. Two weeks after placement, the implants were finally restored with screw-retained or cemented lithium disilicate crowns. A total of 25 patients were treated (26 implants). Most implants were placed in maxillary premolar locations and in lower-density bone. Mean crestal bone loss was 0.58 ± 0.34 mm. Implant survival and success rates were 100%, respectively (follow-up: 14.1 ± 1.5 months). Within the limitations of this study, immediate placement and loading of TM implants resulted in predictable clinical, functional, and esthetic outcomes.

  16. To Analyse the Erosive Potential of Commercially Available Drinks on Dental Enamel and Various Tooth Coloured Restorative Materials – An In-vitro Study

    PubMed Central

    Jindal, Ritu; Mahajan, Sandeep; Sandhu, Sanam; Sharma, Sunila; Kaur, Rajwinder

    2016-01-01

    Introduction With the enormous change in life style pattern of a common man through the past few decades, there has been proportional variation in the amount and frequency of consumption of drinks. An increased consumption of these drinks will concurrently increase enamel surface roughness by demineralization, resulting in hypersensitivity and elevated caries risk. Aim The present study was designed to evaluate the erosive potential of commercially available drinks on tooth enamel and various tooth coloured restorative materials. Materials and Methods Extracted human teeth were taken and divided into four groups i.e. tooth enamel, glass ionomer cement, composite and compomer. Four commercially available drinks were chosen these were Coca -Cola, Nimbooz, Frooti and Yakult. The pH of each drink was measured. Each group was immersed in various experimental drinks for a period of 14 days. The erosive potential of each drink was measured by calculating the change in average surface roughness of these groups after the immersion protocol in various drinks. The data analysis was done by One Way Anova, Post-Hoc Bonferroni, and paired t –test. Results Group II-GIC showed highest values for mean of change in average surface roughness and the values were statistically significant (p<0.001) with tooth enamel, composite and compomer (p=0.002). Coca-cola showed the highest erosive potential and Yakult showed the lowest, there was no statistical significant difference between the results shown by Yakult and Frooti. Conclusion Characteristics which may promote erosion of enamel and tooth coloured restorative materials were surface texture of the material and pH of the drinks. PMID:27437343

  17. Clinical applications of polytetrafluoroethylene (PTFE) tape in restorative dentistry.

    PubMed

    Sattar, M M; Patel, M; Alani, A

    2017-02-10

    Restorative dental procedures are ever developing; one reason for this can be attributed to newer materials with better handling properties and our ability to manipulate them more effectively. As a result various techniques have been described to aid clinicians in obtaining predictable results in restorative dental procedures. This article aims to review the use of plumber's tape to assist in adhesive, endodontic and implant related dental procedures, when compared to other available materials.

  18. Hardening behavior after high-temperature solution treatment of Ag-20Pd-12Au-xCu alloys with different Cu contents for dental prosthetic restorations.

    PubMed

    Kim, Yonghwan; Niinomi, Mitsuo; Hieda, Junko; Nakai, Masaaki; Cho, Ken; Fukui, Hisao

    2014-07-01

    Ag-Pd-Au-Cu alloys have been used widely for dental prosthetic applications. Significant enhancement of the mechanical properties of the Ag-20Pd-12Au-14.5Cu alloy as a result of the precipitation of the β' phase through high-temperature solution treatment (ST), which is different from conventional aging treatment in these alloys, has been reported. The relationship between the unique hardening behavior and precipitation of the β' phase in Ag-20Pd-12Au-xCu alloys (x=6.5, 13, 14.5, 17, and 20mass%) subjected to the high-temperature ST at 1123K for 3.6ks was investigated in this study. Unique hardening behavior after the high-temperature ST also occurs in Ag-20Pd-12Au-xCu alloys (x=13, 17, and 20) with precipitation of the β' phase. However, hardening is not observed and the β' phase does not precipitate in the Ag-20Pd-12Au-6.5Cu alloy after the same ST. The tensile strength and 0.2% proof stress also increase in Ag-20Pd-12Au-xCu alloys (x=13, 14.5, 17, and 20) after the high-temperature ST. In addition, these values after the high-temperature ST increase with increasing Cu content in Ag-20Pd-12Au-xCu alloys (x=14.5, 17, and 20). The formation process of the β' phase can be explained in terms of diffusion of Ag and Cu atoms and precipitation of the β' phase. Clarification of the relationship between hardening and precipitation of the β' phase via high-temperature ST is expected to help the development of more effective heat treatments for hardening in Ag-20Pd-12Au-xCu alloys.

  19. The Chemistry of Modern Dental Filling Materials.

    ERIC Educational Resources Information Center

    Nicholson, John W.; Anstice, H. Mary

    1999-01-01

    Discusses materials used by dentists to restore teeth after decay has been removed. Shows how dental-material science is an interdisciplinary field in which chemistry plays a major part. Reviews the many developments polymer chemistry has contributed to the field of dental fillings. (CCM)

  20. Dental Assistant, AFSC 981X0

    DTIC Science & Technology

    1989-03-01

    career ladder assist dental officers in the performance of restorative, endodontic, orthodontic , pedodontic, periodontic, prosthodontic, and dental... emergency procedures. They assist in the perform- ance of oral/maxillofacial surgery and preventive dentistry. They also clean, sterilize, lubricate, and...representative location for orthodontic , pedodontic, and medi- cal readiness functions Randolph AFB TX Typical USAF Clinic In addition to interviews at the

  1. Team approach between prosthodontics and dental technology.

    PubMed

    Pietrobon, Nicola; Malament, Kenneth A

    2007-01-01

    A collaborative relationship between prosthodontists and dental technicians can greatly improve the esthetic and functional results of restorations. When each discipline takes the time to understand the strengths and challenges of the other, together they can formulate a treatment plan that will culminate in a successful result. The diagnostic waxup gives the dental team a three-dimensional illustration of the problem and allows the patient to view the problem and discuss solutions. Intraoral records taken by the prosthodontist are used with the technician's centric relation jigs to properly mount the casts. When the prosthodontist and technician agree on materials to be used in the fabrication of the provisional prosthesis and master dies, more accurate and functional results are achieved. Of special interest are the tooth preparations: The shape of the margins can enable the dental technician to easily create an accurate restoration. A treatment waxup allows full communication of information about the restoration between the prosthodontist, dental technician, and patient, ensuring that all three parties are satisfied with the look and function before the definitive restoration is made. The type of material and the color properties for the definitive restoration are of utmost importance, and the combined skills and experience of the prosthodontist and dental technician can create an excellent result. This article defines specific points in the restorative process when a collaborative effort between the prosthodontist and the dental technician dramatically improve the end result.

  2. Human enamel veneer restoration: an alternative technique to restore anterior primary teeth.

    PubMed

    Oliveira, Luciana Butini; Tamay, Tereza Keiko; Oliveira, Marta Dutra Machado; Rodrigues, Célia Martins Delgado; Wanderley, Marcia Turolla

    2006-01-01

    Restoration of severely decayed primary teeth is a clinical challenge in Pediatric Dentistry. Among the restorative treatment options, the use of prefabricated crowns and resin composite restorations, either by means of direct or indirect techniques is mentioned in the literature. The purpose of this article is to describe the rehabilitation of primary anterior teeth in a 5-year-old patient. Dental treatment consisted on an anterior space maintainer prosthesis made with natural primary teeth, plus human dental enamel veneer (facet) restorations. The advantages of this technique are better esthetics and the natural enamel has physiologic wear and offers superficial smoothness and cervical adaptation compatible with those of the surrounding teeth.

  3. Effects of various chair-side surface treatment methods on dental restorative materials with respect to contact angles and surface roughness.

    PubMed

    Sturz, Candida R C; Faber, Franz-Josef; Scheer, Martin; Rothamel, Daniel; Neugebauer, Jörg

    2015-01-01

    Available chair-side surface treatment methods may adversely affect prosthetic materials and promote plaque accumulation. This study investigated the effects of treatment procedures on three resin restorative materials, zirconium-dioxide and polyetheretherketone in terms of surface roughness and hydrophobicity. Treatments were grinding with silicon carbide paper or white Arkansas stone, blasting with prophylaxis powder and polishing with diamond paste. Surface roughness was assessed using confocal laser scanning. Hydrophobicity as measured by water contact angle was determined by computerized image analysis using the sessile drop technique. All of the specific surface treatments performed led to significant changes in contact angle values and surface roughness (Ra) values. Median contact angle values ranged from 51.6° to 114°. Ra values ranged from 0.008 µm to 2.917 µm. Air-polishing as well as other polishing procedures increased surface roughness values in all materials except zirconium dioxide. Polyetheretherketone displayed greatest change in contact angle values after air-polishing treatment.

  4. Dental Assistants

    MedlinePlus

    ... help keep the dental office running smoothly. Important Qualities Detail oriented. Dental assistants must follow specific rules and protocols, such as infection control procedures, when helping dentists treat patients. Assistants also ...

  5. Influence of the fabrication process on the in vitro performance of fixed dental prostheses with zirconia substructures.

    PubMed

    Rosentritt, Martin; Kolbeck, Carola; Handel, Gerhard; Schneider-Feyrer, Sibylle; Behr, Michael

    2011-12-01

    Chipping of the applied veneering ceramic is reported to be a main clinical failure type of computer-aided design/computer-aided manufacturing- or manually copy-milled zirconia restorations. The aim of this in vitro study was to investigate whether different substructure designs and veneering processes done by different dental technicians do significantly influence chipping in zirconia-based all-ceramic fixed dental prostheses during simulated oral service. Five groups (n = 8 per group) of three-unit zirconia substructures were fabricated in three different laboratories using copy-milling technique. Three series were veneered with identical porcelain (groups 1-3) and one with a second different porcelain (group 4). The fifth group was milled to final contour design without veneering. Dimensions of the connector areas were determined. All fixed partial dentures (FPDs) were adhesively boned on human teeth and thermally cycled and mechanically loaded (1.2 × 10(6) × 50 N; 6,000 × 5°C/55°C) using human antagonists. Restorations were monitored during thermal cycling and mechanical loading (TCML). FPDs which survived were loaded to fracture. FPDs which failed during TCML were investigated with fractographic means. During TCML, chipping took place in groups 1 (two times), 2 (four times) and 3 (five times) (Table 1). Chipping areas varied between 2.3 mm(2) (group 3) and 58.7 mm(2) (group 2). Groups 4 and 5 provided no failures during TCML. Failure in all cases started from contact points, where superficial wear and disruption of the porcelain were found. No significant correlation could be determined between connector thickness and number of failures. Median fracture results varied between 1,011 N (group 3) and 2,126 N (group 2). The results show the necessity of considering individual design and manufacturing of restorations as well as contact situation. Advanced technical training on zirconia-based restorations is recommended.

  6. A philosophy for restoring virgin caries.

    PubMed

    Henry, Dan B

    2008-01-01

    This paper demonstrates and discusses the clinical relevance for the use of direct gold, especially in restoring virgin caries in the modern restorative dental practice. In addition, this article is intented to highlight the advantages for oral health of placing restorative materials with the highest probability of long-term success. Also, this paper demonstrates the use of the latest formula of direct gold (E-Z Gold), developed by Dr Lloyd Baum of Loma Linda, CA, USA, and how this new product has made it practical to include direct gold restorations as an integral part of an active restorative practice.

  7. Joining Dental Ceramic Layers With Glass

    PubMed Central

    Saied, MA; Lloyd, IK; Haller, WK; Lawn, BR

    2011-01-01

    Objective Test the hypothesis that glass-bonding of free-form veneer and core ceramic layers can produce robust interfaces, chemically durable and aesthetic in appearance and, above all, resistant to delamination. Methods Layers of independently produced porcelains (NobelRondo™ Press porcelain, Nobel BioCare AB and Sagkura Interaction porcelain, Elephant Dental) and matching alumina or zirconia core ceramics (Procera alumina, Nobel BioCare AB, BioZyram yttria stabilized tetragonal zirconia polycrystal, Cyrtina Dental) were joined with designed glasses, tailored to match thermal expansion coefficients of the components and free of toxic elements. Scanning electron microprobe analysis was used to characterize the chemistry of the joined interfaces, specifically to confirm interdiffusion of ions. Vickers indentations were used to drive controlled corner cracks into the glass interlayers to evaluate the toughness of the interfaces. Results The glass-bonded interfaces were found to have robust integrity relative to interfaces fused without glass, or those fused with a resin-based adhesive. Significance The structural integrity of the interfaces between porcelain veneers and alumina or zirconia cores is a critical factor in the longevity of all-ceramic dental crowns and fixed dental prostheses. PMID:21802131

  8. Feasibility and validation of virtual autopsy for dental identification using the Interpol dental codes.

    PubMed

    Franco, Ademir; Thevissen, Patrick; Coudyzer, Walter; Develter, Wim; Van de Voorde, Wim; Oyen, Raymond; Vandermeulen, Dirk; Jacobs, Reinhilde; Willems, Guy

    2013-05-01

    Virtual autopsy is a medical imaging technique, using full body computed tomography (CT), allowing for a noninvasive and permanent observation of all body parts. For dental identification clinically and radiologically observed ante-mortem (AM) and post-mortem (PM) oral identifiers are compared. The study aimed to verify if a PM dental charting can be performed on virtual reconstructions of full-body CT's using the Interpol dental codes. A sample of 103 PM full-body CT's was collected from the forensic autopsy files of the Department of Forensic Medicine University Hospitals, KU Leuven, Belgium. For validation purposes, 3 of these bodies underwent a complete dental autopsy, a dental radiological and a full-body CT examination. The bodies were scanned in a Siemens Definition Flash CT Scanner (Siemens Medical Solutions, Germany). The images were examined on 8- and 12-bit screen resolution as three-dimensional (3D) reconstructions and as axial, coronal and sagittal slices. InSpace(®) (Siemens Medical Solutions, Germany) software was used for 3D reconstruction. The dental identifiers were charted on pink PM Interpol forms (F1, F2), using the related dental codes. Optimal dental charting was obtained by combining observations on 3D reconstructions and CT slices. It was not feasible to differentiate between different kinds of dental restoration materials. The 12-bit resolution enabled to collect more detailed evidences, mainly related to positions within a tooth. Oral identifiers, not implemented in the Interpol dental coding were observed. Amongst these, the observed (3D) morphological features of dental and maxillofacial structures are important identifiers. The latter can become particularly more relevant towards the future, not only because of the inherent spatial features, yet also because of the increasing preventive dental treatment, and the decreasing application of dental restorations. In conclusion, PM full-body CT examinations need to be implemented in the

  9. Lip Lifting: Unveiling Dental Beauty.

    PubMed

    Stanley, Kyle; Caligiuri, Matthew; Schlichting, Luís Henrique; Bazos, Panaghiotis K; Magne, Michel

    2017-01-01

    The focus for the achievement of complete success in the esthetic zone has traditionally been on addressing deficiencies of intraoral hard and soft tissue. Often, these deficiencies are accompanied by esthetic concerns regarding the lips that are routinely neglected by the dental team. A predictable plastic surgery technique - the lip lift - has been used for decades to enhance lip esthetics by shortening the senile upper lip to achieve a more youthful appearance. Over the years, this technique has been refined and used in many different ways, allowing its routine incorporation into full facial esthetic planning. Through restoration of the upper lip to its optimal position, the artistry of the dentist and dental technician can truly be appreciated in the rejuvenated smile. By the introduction of this minimally invasive surgical technique to the dental community, patients stand to benefit from a comprehensive orofacial approach to anterior dental esthetic planning.

  10. 78 FR 24761 - National Institute of Dental & Craniofacial Research; Notice of Closed Meetings

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-26

    ... commercial property such as patentable material, and personal information concerning individuals associated... Emphasis Panel; Design and Development of Novel Dental Composite Restorative Systems Review Panel....

  11. Dental sepsis.

    PubMed

    Mueller, P O; Lowder, M Q

    1998-08-01

    Dental sepsis or periapical abscess formation constitutes a large percentage of dental conditions that afflict horses. Dental sepsis occurs when the pulp chamber of the tooth is exposed to the oral cavity or external environment, allowing bacterial localization with resulting infection. Although acute, primary, septic pulpitis in horses is rare, dental sepsis often results from colonization of the pulp chamber with pathogenic bacteria secondary to maleruption or impaction of teeth with secondary alveolar bone lysis, primary fractures of the tooth, mandible, or maxilla, periodontal disease, or infundibular necrosis. The sequela to pulpal infection are extensions into the periradicular tissues and mandibular or maxillary periapical abscess formation.

  12. River restoration

    NASA Astrophysics Data System (ADS)

    Wohl, Ellen; Angermeier, Paul L.; Bledsoe, Brian; Kondolf, G. Mathias; Macdonnell, Larry; Merritt, David M.; Palmer, Margaret A.; Poff, N. Leroy; Tarboton, David

    2005-10-01

    River restoration is at the forefront of applied hydrologic science. However, many river restoration projects are conducted with minimal scientific context. We propose two themes around which a research agenda to advance the scientific basis for river restoration can be built. First, because natural variability is an inherent feature of all river systems, we hypothesize that restoration of process is more likely to succeed than restoration aimed at a fixed end point. Second, because physical, chemical, and biological processes are interconnected in complex ways across watersheds and across timescales, we hypothesize that restoration projects are more likely to be successful in achieving goals if undertaken in the context of entire watersheds. To achieve restoration objectives, the science of river restoration must include (1) an explicit recognition of the known complexities and uncertainties, (2) continued development of a theoretical framework that enables us to identify generalities among river systems and to ask relevant questions, (3) enhancing the science and use of restoration monitoring by measuring the most effective set of variables at the correct scales of measurement, (4) linking science and implementation, and (5) developing methods of restoration that are effective within existing constraints. Key limitations to river restoration include a lack of scientific knowledge of watershed-scale process dynamics, institutional structures that are poorly suited to large-scale adaptive management, and a lack of political support to reestablish delivery of the ecosystem amenities lost through river degradation. This paper outlines an approach for addressing these shortcomings.

  13. Dental fractures on acute exposure to high altitude.

    PubMed

    Zadik, Yehuda; Einy, Shmuel; Pokroy, Russell; Bar Dayan, Yaron; Goldstein, Liav

    2006-06-01

    There is little in the literature on dental restoration breakage in the aviation environment since reports of problems in combat aviators in War World II. We report two cases of dental fractures during acute exposure to a hypobaric environment. Case 1 was a young officer who suffered an amalgam restoration breakage during a 25,000-ft decompression chamber simulation. Case 2 occurred in an experienced aviator who had a tooth cusp fracture in a molar with a defective amalgam restoration during an unpressurized helicopter flight to 18,000 ft. In both cases, after removing the defective fillings, deep secondary caries were found; both teeth were successfully restored. Because hard-tissue tooth fracture during a high-altitude flight is a rare event, few flight surgeons or dentists are familiar with this phenomenon. We recommend regular dental examinations with careful assessment of previous dental restorations in aircrew subject to decompression.

  14. Complete oral rehabilitation in a case with severe dental fluorosis

    PubMed Central

    Joshi, Nikhil; Palaskar, Jayant; Joshi, Mahasweta; Kathariya, Rahul

    2014-01-01

    The authors have presented a technique of full occlusal rehabilitation in a case of severe dental fluorosis. In this technique, maxillary and mandibular anterior teeth were simultaneously prepared and restored first. This was followed by simultaneous preparation of maxillary and mandibular posterior teeth that were restored in canine guided occlusion. The technique and sequence followed here is unique and is not available in dental literature. This technique reduces number of appointments while fulfilling all objectives. Periodontal follow-up over 3 years was satisfactory. A restorative treatment protocol has been devised for fluorosis which will act as a guide for the dental practitioners. PMID:25516876

  15. Dental Hygienist.

    ERIC Educational Resources Information Center

    Ohio State Univ., Columbus. Center on Education and Training for Employment.

    This document, which is designed for use in developing a tech prep competency profile for the occupation of dental hygienist, lists technical competencies and competency builders for 13 units pertinent to the health technologies cluster in general and 9 units specific to the occupation of dental hygienist. The following skill areas are covered in…

  16. Zirconia-parylene multilayer thin films for enhanced fracture resistance of dental ceramics.

    PubMed

    Teixeira, E C; Piascik, J R; Stoner, B R; Thompson, J Y

    2009-10-01

    Recent research has shown that the application of specific thin films can enhance the material properties of a laminate construct. In this study, the effect of different mono/multilayered films on the strength of a ceramic specimen is demonstrated. It is well established that cracks can initiate and/or propagate from the internal surfaces of all-ceramic dental restorations. Modifying that surface by thin-film deposition might help increase clinical longevity and applicability. Specimens were divided into the following groups according to different surface treatments received: uncoated (control group), 10 microm yttria-stabilized zirconia (YSZ) thin film, 10 microm parylene thin film, 9.75 microm YSZ + 0.25 microm parylene film, and a multilayered film (five layers of 1.25 microm YSZ + 0.75 microm parylene). Depositions were performed using a radio-frequency magnetron sputter system (working pressure 15 mT, 150 degrees C, 30:1 Ar/O2 gas ratio) to produce the YSZ layers, and a vapour deposition process was used to produce the parylene layers. Flexural strength measurements were carried out by three-point bending (span = 10 mm) in a servo-electric material testing system in deioinized (DI) water (37 degrees C). The results showed that the strength of the specimen significantly increased with the deposition of all types of coating, showing the greatest increase with the multilayered film (approximately 32 per cent). It is hypothesized that a multilayer thin film (brittle/ductile) can promote crack deflection, causing strength enhancement of the brittle construct.

  17. Periodontal health--challenges in restorative dentistry.

    PubMed

    Reeves, J

    2014-05-01

    As the population ages and life expectancy increases, clinicians today find themselves in the wake of an ever-growing demand for high-quality aesthetic dental treatment, by increasingly informed patients. The long-term success of both cosmetic and restorative dentistry is dependent on well designed restorations and the health of the periodontal tissues. Overhanging restorations, full crown restorations with poor marginal fit, and implant-supported prosthetics with inadequate hygiene access all increase the risk for periodontal sequelae and interproximal caries. When planning restorative treatment, consideration should be given to the restorative design, the need for hygiene access and the location of intended implants. In addition, the patient's manual dexterity and ability to manipulate oral hygiene aids is a crucial consideration, as is adequate access for the hygienist to manually debride and maintain the restorations.

  18. Using digital technology to enhance restorative dentistry.

    PubMed

    Fasbinder, Dennis

    2012-10-01

    While there are many benefits for dental practices that incorporate digital systems into their workflow, the dental team must first master the learning curve involved in order to maximize their advantages for creating well-fitting restorations. This article describes the current systems-both digital impression systems and chairside CAD/CAM systems-including software and digital cameras and scanners. The author emphasizes that to consistently capture accurate impressions with this technology, the dental team must continue to rely on traditional skills such as achieving optimal soft-tissue retraction and maintaining moisture control and isolation.

  19. Dental Caries Experience and Use of Dental Services among Brazilian Prisoners

    PubMed Central

    Leite Cavalcanti, Alessandro; Araujo Rodrigues, Iris Sant´Anna; de Melo Silveira, Ingrid Thays; Sarmento de Oliveira, Thaliny Batista; de Almeida Pinto, Magaly Suenya; Cabral Xavier, Alidianne Fabia; Dias de Castro, Ricardo; Nascimento Padilha, Wilton Wilney

    2014-01-01

    This ross-sectional study involving 127 male prisoners evaluates the use of dental services and dental caries among Brazilian inmates. Data were collected by interview and clinical examination. Sociodemographic and sentencing information as well as use of dental services, self-reported dental morbidity, self-perception, and oral health impacts were investigated. The mean DMFT index value was 19.72. Of the components, the decayed component showed the highest mean value (11.06 ± 5.37). Statistically significant association was found between DMFTs with values from 22 to 32 and oral health satisfaction (p = 0.002), difficulty speaking (p = 0.024), shame of talking (p = 0.004) and smiling (p < 0.001). Regarding the use of dental services, 80% had their last dental appointment less than one year ago, with most visits occurring in prison (80%), with restorative treatment (32%), followed by dental pain (26.4%), being the main reasons for such appointments. Most prisoners used dental services provided by the prison. Although restorative treatment has been the main reason for the use of dental services, “decayed” and “missing” components contributed to the high mean DMFT index. PMID:25429680

  20. Dental caries experience and use of dental services among Brazilian prisoners.

    PubMed

    Cavalcanti, Alessandro Leite; Rodrigues, Iris Sant Anna Araujo; de Melo Silveira, Ingrid Thays; de Oliveira, Thaliny Batista Sarmento; de Almeida Pinto, Magaly Suenya; Xavier, Alidianne Fabia Cabral; de Castro, Ricardo Dias; Padilha, Wilton Wilney Nascimento

    2014-11-25

    This ross-sectional study involving 127 male prisoners evaluates the use of dental services and dental caries among Brazilian inmates. Data were collected by interview and clinical examination. Sociodemographic and sentencing information as well as use of dental services, self-reported dental morbidity, self-perception, and oral health impacts were investigated. The mean DMFT index value was 19.72. Of the components, the decayed component showed the highest mean value (11.06 ± 5.37). Statistically significant association was found between DMFTs with values from 22 to 32 and oral health satisfaction (p = 0.002), difficulty speaking (p = 0.024), shame of talking (p = 0.004) and smiling (p < 0.001). Regarding the use of dental services, 80% had their last dental appointment less than one year ago, with most visits occurring in prison (80%), with restorative treatment (32%), followed by dental pain (26.4%), being the main reasons for such appointments. Most prisoners used dental services provided by the prison. Although restorative treatment has been the main reason for the use of dental services, "decayed" and "missing" components contributed to the high mean DMFT index.

  1. Interim Prosthesis Options for Dental Implants.

    PubMed

    Siadat, Hakimeh; Alikhasi, Marzieh; Beyabanaki, Elaheh

    2016-01-24

    Dental implants have become a popular treatment modality for replacing missing teeth. In this regard, the importance of restoring patients with function during the implant healing period has grown in recent decades. Esthetic concerns, especially in the anterior region of the maxilla, should also be considered until the definitive restoration is delivered. Another indication for such restorations is maintenance of the space required for esthetic and functional definitive restorations in cases where the implant site is surrounded by natural teeth. Numerous articles have described different types of interim prostheses and their fabrication techniques. This article aims to briefly discuss all types of implant-related interim prostheses by different classification including provisional timing (before implant placement, after implant placement in unloading and loading periods), materials, and techniques used for making the restorations, the type of interim prosthesis retention, and definitive restoration. Furthermore, the abutment torque for such restorations and methods for transferring the soft tissue from interim to definitive prostheses are addressed.

  2. Electrochemical impedance spectroscopy in understanding the influence of ultrasonic dental scaling on the dental structure-dental filling interface.

    PubMed

    Andrei, Mihai; Pirvu, Cristian; Demetrescu, Ioana

    2014-12-01

    The purpose of this study was to investigate the effect of ultrasonic scaling on teeth restored with a light-cured resin. Ultrasonic scaling is a very popular periodontal therapy among dentists, and used for the removal of dental plaque and calculus in order to reduce and eliminate inflammation. Given the fact that most ultrasonic devices are used at high frequencies to perform scaling, undesirable consequences, such as loss of adhesion and increase in surface roughness, may occur in teeth that have been restored with light-cured resins. Electrochemical impedance spectroscopy (EIS) and scanning electron microscopy were used to investigate the effects of ultrasonic treatments at the dental material-hard dental tissue interface. After ultrasonic scaling, EIS measurements were performed on a human tooth that had been restored with a light-cured resin filling. The data were analyzed and the influence of ultrasound was shown after visualization of the hard dental tissues and the dental material as equivalent electrical circuits. The study revealed, through EIS measurements, that ultrasonic scaling affected the resistance of the light-cured resin filling and dentin, whereas the enamel was affected only slightly. Scanning electron microscopy revealed an increase in roughness of the dental material.

  3. Ablation by-products of dental materials from the Er:YAG laser and the dental handpiece

    NASA Astrophysics Data System (ADS)

    Wigdor, Harvey A.; Visuri, Steven R.; Walsh, Joseph T., Jr.

    1995-05-01

    Recently there has been much interest in lasers and their potential use to replace the dental drill. The research has been directed towards vital dental tissues. It must be understood that any laser to be used in dentistry which will replace the dental drill must also ablate and remove existing dental materials. Some concern exists about the ablation products when the Er:YAG laser is used to ablate dental materials. It is incumbent on the professionals using these lasers to understand the materials being produced by these lasers and protect themselves and their patients from possible toxic products. It is the intent of this paper to evaluate the products produced by the ablation of both dental amalgam and composite dental restorative materials and compare them with those produced by the traditional dental handpiece (drill).

  4. Registered Dental Hygienists as Dental Students.

    ERIC Educational Resources Information Center

    Arnold, Janet; Shugars, Daniel A.

    1985-01-01

    Surveys conducted to (1) investigate why dental hygienists choose to become dentists, (2) evaluate their success in dental school, (3) assess the experience of those who had entered dental school, and (4) gauge the level of interest among dental hygienists in applying to dental school are discussed. (Author/MLW)

  5. 21 CFR 872.4200 - Dental handpiece and accessories.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...) Identification. A dental handpiece and accessories is an AC-powered, water-powered, air-powered, or belt-driven... restorations, such as fillings, and for cleaning teeth. (b) Classification. Class I....

  6. 21 CFR 872.4200 - Dental handpiece and accessories.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...) Identification. A dental handpiece and accessories is an AC-powered, water-powered, air-powered, or belt-driven... restorations, such as fillings, and for cleaning teeth. (b) Classification. Class I....

  7. Dental sealants

    MedlinePlus

    ... few quick steps. There is no drilling or scraping of the molars. Your dentist will: Clean the ... Dental sealants. Updated October 19, 2016. ADA.org Web site. www.ada.org/en/member-center/oral- ...

  8. Dental Sealants

    MedlinePlus

    ... form does not collect any actual information. External Web Site Policy This graphic notice ( ) means that you are ... the link. Home Contact Us Viewers and Players Site Map FOIA Web Policies Privacy Policy National Institute of Dental and ...

  9. 75 FR 16511 - Pentron Clinical Technologies, a Wholly-Owned Subsidiary of Kerr Dental/Sybron Dental...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-01

    ... such as dental prosthetics, dental composites, dental impressions, dental adhesives, and other dental... prosthetics, dental composites, dental impressions, dental adhesives, and other dental materials to...

  10. Dental Emergencies

    PubMed Central

    Symington, J.M.

    1988-01-01

    Patients with dental emergencies sometimes present to their physician. This article outlines the role of the physician in the management of dental patients who have suffered traumatic injuries, postoperative hemorrhage, pain, and infection. It deals with those difficulties for which the physician may easily prescribe treatment and outlines the treatment that would be undertaken by a dentist who receives such a patient on referral. PMID:21253249

  11. Current status of zirconia restoration.

    PubMed

    Miyazaki, Takashi; Nakamura, Takashi; Matsumura, Hideo; Ban, Seiji; Kobayashi, Taira

    2013-10-01

    During the past decade, zirconia-based ceramics have been successfully introduced into the clinic to fabricate fixed dental prostheses (FDPs), along with a dental computer-aided/computer-aided manufacturing (CAD/CAM) system. In this article (1) development of dental ceramics, (2) the current status of dental CAD/CAM systems, (3) CAD/CAM and zirconia restoration, (4) bond between zirconia and veneering ceramics, (5) bond of zirconia with resin-based luting agents, (6) surface finish of zirconia restoration and antagonist enamel wear, and (7) clinical evaluation of zirconia restoration are reviewed. Yttria partially stabilized tetragonal zirconia polycrystalline (Y-TZP) showed better mechanical properties and superior resistance to fracture than other conventional dental ceramics. Furthermore, ceria-stabilized tetragonal zirconia polycrystalline and alumina nanocomposites (Ce-TZP/A) had the highest fracture toughness and had resistance to low-temperature aging degradation. Both zirconia-based ceramics have been clinically available as an alternative to the metal framework for fixed dental prostheses (FDPs). Marginal adaptation of zirconia-based FDPs is acceptable for clinical application. The most frequent clinical complication with zirconia-based FDPs was chipping of the veneering porcelain that was affected by many factors. The mechanism for the bonding between zirconia and veneering ceramics remains unknown. There was no clear evidence of chemical bonding and the bond strength between zirconia and porcelain was lower than that between metal and porcelain. There were two alternatives proposed that might avoid chipping of veneering porcelains. One was hybrid-structured FDPs comprising CAD/CAM-fabricated porcelain parts adhering to a CAD/CAM fabricated zirconia framework. Another option was full-contour zirconia FDPs using high translucent zirconia. Combined application of silica coating and/or silane coupler, and 10-methacryloyloxydecyl dihydrogen phosphate is

  12. Relationship of children's anxiety to their potential dental health behaviour.

    PubMed

    Wright, F A

    1980-08-01

    In this study of 200 New Zealand schoolchildren aged 7-13 years, a questionnaire interview was used to gain information related to estimating dental anxiety and general illness anxiety. Information related to sociodemographic differences, belief differences, and an estimate of potential health behaviour was also collected. Oral examinations were performed and the number of dental restorations present recorded. Dental anxiety was associated with memory of pain during a dental visit. The number of restorations present, and a history of pain during a dental visit, were important predictors of illness anxiety. Neither dental anxiety nor illness anxiety operating alone provided an estimate of future dental health behaviour. Dental anxiety and illness anxiety operated through a complex interplay of variables. A stepwise multiple regression technique was used to determine the possible pathways to potential dental health behaviour. Perceived vulnerability to dental caries and perceived severity of dental disease were important in the prediction of potential denture wearing; school attended and ethnic background were useful predictors of potential extraction seeking; and school grade and level of perceived internal control were predictors of potential preventive visitation.

  13. Ceramic restorations of anterior teeth without proximal reduction: a case report.

    PubMed

    Nakamura, Takashi; Nakamura, Toshio; Ohyama, Tatsuo; Wakabayashi, Kazumichi

    2003-01-01

    The primary advantage of using all-ceramic restorations is to reproduce a color and translucency close to those of the natural tooth. Additionally, it is anticipated that the use of an adhesion technique will allow a ceramic restoration without removing tooth structure in some patients. This case report describes the use of proximally bonded ceramic restorations for the closure of an anterior diastema without proximal tooth reduction. A silane coupling agent and a resin cement were used for bonding. The diastema was close with the ceramic restorations, which provided a natural appearance of the teeth. It was concluded that ceramic restorations without proximal tooth reduction was effective in improving esthetics, if the case was properly selected.

  14. Optical approach in characterizing dental biomaterials

    NASA Astrophysics Data System (ADS)

    Demoli, Nazif; Vučić, Zlatko; Milat, Ognjen; Gladić, Jadranko; Lovrić, Davorin; Pandurić, Vlatko; Marović, Danijela; Moguš-Milanković, Andrea; Ristić, Mira; Čalogović, Marina; Tarle, Zrinka

    2013-04-01

    The purpose of this paper is to present the current activities of a research collaborative program between three institutions from Zagreb (School of Dental Medicine, Institute of Physics, and Institute Ruđer Bo\\vsković). Within the scope of this program, it is planned to investigate and find guidelines for the refinement of the properties of dental biomaterials (DBs) and of procedures in restorative dental medicine. It is also planned to identify and model the dominant mechanisms which control polymerization of DBs. The materials to be investigated include methacrylate based composite resins, new composite materials with amorphous calcium phosphate, silorane based composite resins, glass-ionomer cements, and giomer.

  15. Image post-processing in dental practice.

    PubMed

    Gormez, Ozlem; Yilmaz, Hasan Huseyin

    2009-10-01

    Image post-processing of dental digital radiographs, a function which used commonly in dental practice is presented in this article. Digital radiography has been available in dentistry for more than 25 years and its use by dental practitioners is steadily increasing. Digital acquisition of radiographs enables computer-based image post-processing to enhance image quality and increase the accuracy of interpretation. Image post-processing applications can easily be practiced in dental office by a computer and image processing programs. In this article, image post-processing operations such as image restoration, image enhancement, image analysis, image synthesis, and image compression, and their diagnostic efficacy is described. In addition this article provides general dental practitioners with a broad overview of the benefits of the different image post-processing operations to help them understand the role of that the technology can play in their practices.

  16. Testing of DentStat (trademark) and Competing Dental Materials

    DTIC Science & Technology

    2014-06-13

    direct dental repair materials. They are made of calcium or strontium aluminofluoro-silicate glass powder (base) combined with a water-soluble polymer...the 1970s. Glass ionomers (GI) are tooth colored dental restorative materials that consist of an acid-degradable glass made of calcium or strontium

  17. CAMBRA: An Examination of Change in the Dental Profession

    ERIC Educational Resources Information Center

    Young, Douglas

    2010-01-01

    Dental caries is a disease process, one that will not be eliminated by tooth repair alone. Caries is the most prevalent disease of children and the primary reason for most restorative dental visits in both adults and children. A risk-based approach to managing caries targets those in greatest jeopardy for contracting the disease and provides…

  18. Dental surgery in ancient Egypt.

    PubMed

    Blomstedt, Patric

    2013-01-01

    Many different surgical procedures have over the years been attributed to the ancient Egyptians. This is also true regarding the field of dental surgery. The existence of dentists in ancient Egypt is documented and several recipes exist concerning dental conditions. However, no indications of dental surgery are found in the medical papyri or in the visual arts. Regarding the osteological material/mummies, the possible indications of dental surgery are few and weak. There is not a single example of a clear tooth extraction, nor of a filling or of an artificial tooth. The suggested examples of evacuation of apical abscesses can be more readily explained as outflow sinuses. Regarding the suggested bridges, these are constituted of one find likely dating to the Old Kingdom, and one possibly, but perhaps more likely, dating to the Ptolemaic era. Both seem to be too weak to have served any possible practical purpose in a living patient, and the most likely explanation would be to consider them as a restoration performed during the mummification process. Thus, while a form of dentistry did certainly exist in ancient Egypt, there is today no evidence of dental surgery.

  19. Dental Calculus Arrest of Dental Caries

    PubMed Central

    Keyes, Paul H.; Rams, Thomas E.

    2016-01-01

    Background An inverse relationship between dental calculus mineralization and dental caries demineralization on teeth has been noted in some studies. Dental calculus may even form superficial layers over existing dental caries and arrest their progression, but this phenomenon has been only rarely documented and infrequently considered in the field of Cariology. To further assess the occurrence of dental calculus arrest of dental caries, this study evaluated a large number of extracted human teeth for the presence and location of dental caries, dental calculus, and dental plaque biofilms. Materials and methods A total of 1,200 teeth were preserved in 10% buffered formal saline, and viewed while moist by a single experienced examiner using a research stereomicroscope at 15-25× magnification. Representative teeth were sectioned and photographed, and their dental plaque biofilms subjected to gram-stain examination with light microscopy at 100× magnification. Results Dental calculus was observed on 1,140 (95%) of the extracted human teeth, and no dental carious lesions were found underlying dental calculus-covered surfaces on 1,139 of these teeth. However, dental calculus arrest of dental caries was found on one (0.54%) of 187 evaluated teeth that presented with unrestored proximal enamel caries. On the distal surface of a maxillary premolar tooth, dental calculus mineralization filled the outer surface cavitation of an incipient dental caries lesion. The dental calculus-covered carious lesion extended only slightly into enamel, and exhibited a brown pigmentation characteristic of inactive or arrested dental caries. In contrast, the tooth's mesial surface, without a superficial layer of dental calculus, had a large carious lesion going through enamel and deep into dentin. Conclusions These observations further document the potential protective effects of dental calculus mineralization against dental caries. PMID:27446993

  20. Dental Caries

    PubMed Central

    Burgess, Ralph C.

    1988-01-01

    Dental caries is one of the most prevalent diseases afflicting mankind. It reached a peak in the 1950s but has been declining drastically in recent years in children and young adults. This article describes the three contributing factors in dental caries: microbial plaque, tooth susceptibility, and diet, and discusses practical preventive measures which help to reduce caries incidence. Some of these, such as vaccines and antimicrobial varnishes, are still in the research stages, while others, such as sucrose substitutes, low-calorie sweeteners, and limitation of frequency of sugar snacks are well established and can be promoted by family physicians. PMID:21253193

  1. Dental dam patch: an effective intraoral repair technique using cyanoacrylate.

    PubMed

    Liebenberg, W H

    1998-10-01

    Secondary dental dam retention is a critical component of successful dental dam isolation and relates to the provision of an effective seal at the dam/tooth junction. Restorative success can be compromised if this seal is inadvertently interrupted during the operative effort. One such periodic mishap is entanglement of the bur and the interdental dam strip during caries or restorative removal. This invariably results in a gaping interproximal defect in the dam. This article discusses the importance of optimum isolation as it relates to current "wet bonding" adhesive procedures, and introduces a repair technique using a patch of dental dam and cyanoacrylate.

  2. Material and clinical considerations for full-coverage indirect restorations.

    PubMed

    Martin, Margaret P

    2012-11-01

    Because dental ceramics have been used for decades and continuously improved over the years, there is a plethora of information regarding their material characteristics, applications, and contraindications. Each restorative ceramic material demonstrates benefits and disadvantages, making it difficult for dentists to research, retain, and apply the ideal material for individual restorations and/or combination cases. This article outlines the applications and benefits of dental ceramics in general and examines and reviews the current ceramic alternatives available for restorative dentistry today. It also discusses the material composition and properties of a recently introduced new classification of indirect material: resin nano-ceramic.

  3. Acupuncture in the management of acute dental pain.

    PubMed

    Grillo, Cássia Maria; Wada, Ronaldo Seichi; da Luz Rosário de Sousa, Maria

    2014-04-01

    Acute dental pain is the main reason for seeking dental services to provide urgent dental care; there is consensus about the use of alternative therapies, such as acupuncture, to control dental pain in pre-dental care. This study aimed to evaluate the use of acupuncture in reducing the intensity of acute dental pain in pre-dental care in patients waiting for emergency dental care, and was conducted at the After-Hours Emergency Dental Clinic of Piracicaba Dental School, and at the Emergency Center Dental Specialties I in Piracicaba, São Paulo, Brazil. The sample consisted of 120 patients. The Visual Analog Scale (VAS) was used to measure pain intensity. All patients underwent one session of acupuncture; the points LI4, ST44 and CV23 were selected and were used alone or in combinations. Reduction in pain was observed in 120 patients (mean initial VAS=6.558±1.886, p<0; mean final VAS=0.962±2.163, p<0.00001). The results of this study indicate that acupuncture analgesia could be a technical adjunct to pain control in patients with acute dental pain, contributing to the restoration of health with social benefit.

  4. Utilization of dental general anaesthesia for children.

    PubMed

    Karim, Zarina Abdul; Musa, Normaizura; Noor, Siti Noor Fazliah Mohd

    2008-07-01

    Dental treatment under general anaesthesia may be needed for some children and adolescents due to medical or behaviour problem. The objective of the study is to identify the type of treatment that has been carried out under GA in Hospital Universiti Sains Malaysia (HUSM). A retrospective record review study from hospital records of dental patients (under 18 years old) receiving dental treatment under GA from 2003 until 2007 were retrieved from the database. Information such as the reason for GA, and the type of treatment provided was recorded in data sheet. The data were analyzed using SPSS 12.0.1 for Windows. It was checked and verified for errors. A total of 349 cases were treated of which 43.6% had medical problems. Patients were mostly diagnosed to have rampant caries (77.1%) and some of them have behavioural problems (34.4%). Treatment pattern in deciduous dentition revealed more extraction (97.8%) as compared to restoration (75.7%) whereas in permanent dentition more restoration was done (24.3%) as compared to extraction (2.2%). Majority of the restorations were done using Glass Ionomer Cements (47.5%). Biopsy (4.3%) contributed mainly to the surgery (24.1%) done during GA. General anesthesia is necessary when dental disease is interfering with health and general well-being of patient and it can facilitated dental treatment allowing dentists to benefit from improved treatment conditions and provide a higher quality of care.

  5. Translucency measurements in teeth and dental materials

    NASA Astrophysics Data System (ADS)

    Rawicz, Andrew H.; Melnyk, Ivan; Kowalski, Pawel

    2003-06-01

    Exact color matching of dental restorative materials to vital teeth is a difficult task. There are several reasons for this difficulty and they will be elaborated upon in the presentation. One of the most important reasons is the fact that teeth, as well as dental restorative materials are translucent, and thus the color impression is a product of light scattering, back scattering, transmission, and spectral modifications inside of these objects. Classic colorimetry is insufficient to provide an exact color match. Additional information about the translucency factor of the considered object (material and geometry) is necessary to provide full reproducibility. Translucency has a direct effect on perceived brightness. In this article we describe the TransluDent, a complementary product to ColorDent, which measures translucency of teeth and dental materials. TransluDent determines translucency by measuring light transmitted through an object and light scattered inside of the object. The translucency measurements were performed on two groups of subjects. One group consisted of people in their twenties and the second group of subjects was in fifties. For comparison several sets of dental shade-guides were also tested. The great discrepancy in translucency factor between human teeth and popular on the market shades may explain difficulty in color matching of dental restorative materials to teeth.

  6. Application of Laser Irradiation for Restorative Treatments

    PubMed Central

    Davoudi, Amin; Sanei, Maryam; Badrian, Hamid

    2016-01-01

    Nowadays, lasers are widely used in many fields of medicine. Also, they can be applied at many branches of dental practice such as diagnosis, preventive procedures, restorative treatments, and endodontic therapies. Procedures like caries removal, re-mineralization, and vital pulp therapy are the most noticeable effects of laser irradiation which has gained much attention among clinicians. With controlled and appropriate wavelength, they can help stimulating dentinogenesis, controlling pulpal hemorrhage, sterilization, healing of collagenic proteins, formation of a fibrous matrix, and inducing hard tissue barrier. Nevertheless, there are many controversies in literatures regarding their effects on the quality of bonded restorations. It hampered a wide application of lasers in some aspects of restorative dentistry and requirements to identify the best way to use this technology. The aim of this mini review is to explain special characteristics of laser therapy and to introduce the possible applications of laser devices for dental purposes. PMID:27990188

  7. Broadening the Scope of Dental Education.

    ERIC Educational Resources Information Center

    Loe, Harald

    1992-01-01

    Scientific and technological advances affecting dental education in the near future are examined, including the growing role of saliva in diagnosis, direct imaging methods, biomaterials research, computer-aided design and manufacturing, molecular biology, and new restorative dentistry. It is argued that dentistry should be a fully recognized…

  8. Holography And Holometry Applications In Dental Research

    NASA Astrophysics Data System (ADS)

    Willenborg, George C.

    1987-06-01

    The earliest reference to holographic applications appeared in the dental literature in 1972 when Wictorin, Bjelkhagen and Abramson described a method to study elastic deformation of defective gold solder joints in simulated fixed bridges. Their paper, published in the Swedish dental literature, offered a concise presentation of the interferometry technique which led to the development of other research applications of holographic interferometry(holometry) in dentistry. In this presentation, the development and application of the interferometry technique in the dental field will be discussed. Various interesting and potentially useful applications of holography have appeared in the dental literature over the past decade. Some of these, which will be discussed, include the use of holograms as a storage medium for dental study models, multiplexing of computer(CT) scan sections to form white light viewable holograms and the potential application of holographic training aids in the teaching of the basic courses of dental anatomy and restorative dentistry. In addition, some unique related applications will be mentioned including a laser reflection method for accurate non-contact measurement of tooth mobility/movement and a technique for contour mapping of occlusal surfaces to measure wear of restorative materials.

  9. Electrical activity in dental amalgam of submerged divers during welding.

    PubMed

    Ortendahl, T W; Holland, R I

    1987-10-01

    Divers performing underwater manual metal arc welding/cutting (UMMA) have complained about a metallic taste phenomenon. In several dives with voluntary leakage in their diving suits, potential alterations in dental amalgam were registered when they performed UMMA. Polarization resistance values were obtained for the test amalgam cylinders used and the diver's dental restorations. These values, along with the recorded potential values of the amalgam test cylinders and of the diver's dental restorations, enabled us to calculate the depolarizing current, using the law of Ohm. The current depolarizing the amalgam test cylinder did not differ significantly from the mean intermetallic currents between the dental restorations. The clinical effect of intraoral currents when performing UMMA welding should be regarded as small, whereas considerably higher currents should not be ruled out in an intense cutting situation.

  10. Release and toxicity of dental resin composite.

    PubMed

    Gupta, Saurabh K; Saxena, Payal; Pant, Vandana A; Pant, Aditya B

    2012-09-01

    Dental resin composite that are tooth-colored materials have been considered as possible substitutes to mercury-containing silver amalgam filling. Despite the fact that dental resin composites have improved their physico-chemical properties, the concern for its intrinsic toxicity remains high. Some components of restorative composite resins are released in the oral environment initially during polymerization reaction and later due to degradation of the material. In vitro and in vivo studies have clearly identified that these components of restorative composite resins are toxic. But there is a large gap between the results published by research laboratories and clinical reports. The objective of this manuscript was to review the literature on release phenomenon as well as in vitro and in vivo toxicity of dental resin composite. Interpretation made from the recent data was also outlined.

  11. Release and toxicity of dental resin composite

    PubMed Central

    Gupta, Saurabh K.; Saxena, Payal; Pant, Vandana A.; Pant, Aditya B.

    2012-01-01

    Dental resin composite that are tooth-colored materials have been considered as possible substitutes to mercury-containing silver amalgam filling. Despite the fact that dental resin composites have improved their physico-chemical properties, the concern for its intrinsic toxicity remains high. Some components of restorative composite resins are released in the oral environment initially during polymerization reaction and later due to degradation of the material. In vitro and in vivo studies have clearly identified that these components of restorative composite resins are toxic. But there is a large gap between the results published by research laboratories and clinical reports. The objective of this manuscript was to review the literature on release phenomenon as well as in vitro and in vivo toxicity of dental resin composite. Interpretation made from the recent data was also outlined. PMID:23293458

  12. Natural restoration

    SciTech Connect

    Kamlet, K.S.

    1993-02-01

    After a company pays millions of dollars to clean up contaminated site, its liability may not be over. It may have to spend tens of millions more to restore damaged natural resources under an oft-overlooked Superfund program. Examples of liability are cited in this report from the Exxon Valdez oil spill and a pcb leak which contaminated a harbor.

  13. Methods used by Dental Practice-Based Research Network (DPBRN) dentists to diagnose dental caries

    PubMed Central

    Gordan, Valeria V.; Riley, Joseph L; Carvalho, Ricardo M.; Snyder, John; Sanderson, James L; Anderson, Mary; Gilbert, Gregg H.

    2010-01-01

    Objectives To (1) identify the methods that dentists in The Dental Practice-Based Research Network (DPBRN) use to diagnose dental caries; (2) quantify their frequency of use; and (3) test the hypothesis that certain dentist and dental practice characteristics are significantly associated with their use. Methods A questionnaire about methods used for caries diagnosis was sent to DPBRN dentists who reported doing at least some restorative dentistry; 522 dentists participated. Questions included use of dental radiographs, dental explorer, laser fluorescence, air-drying, fiber optic devices, and magnification, as used when diagnosing primary, secondary/recurrent, or non-specific caries lesions. Variations on the frequency of their use were tested using multivariate analysis and Bonferroni tests. Results Overall, the dental explorer was the instrument most commonly used to detect primary occlusal caries as well as to detect caries at the margins of existing restorations. In contrast, laser fluorescence was rarely used to help diagnose occlusal primary caries. For proximal caries, radiographs were used to help diagnose 75-100% of lesions by 96% of the DPBRN dentists. Dentists who use radiographs most often to assess proximal surfaces of posterior teeth, were significantly more likely to also report providing a higher percentage of patients with individualized caries prevention (p = .040) and seeing a higher percentage of pediatric patients (p = .001). Conclusion Use of specific diagnostic methods varied substantially. The dental explorer and radiographs are still the most commonly used diagnostic methods. PMID:21488724

  14. Rebuilding the ruins: dental services and manpower in Cambodia.

    PubMed

    Durward, C S; Todd, R V

    1991-10-01

    Between 1975 and 1979 Cambodia suffered a massive destruction of its social structures under the Khmer Rouge. The dental profession was almost annihilated and the dental school in Phnom Penh stripped bare. Dental training has now begun again and the long process of restoration is in progress. The ratio of dentists to the population is still pitifully low and public services are concentrated in Phnom Penh and in provincial towns. Traditional dentists provide the only accessible dental care in many places. A primary oral health care system has yet to be developed.

  15. Dental Pulp Defence and Repair Mechanisms in Dental Caries

    PubMed Central

    Farges, Jean-Christophe; Alliot-Licht, Brigitte; Renard, Emmanuelle; Ducret, Maxime; Gaudin, Alexis; Smith, Anthony J.; Cooper, Paul R.

    2015-01-01

    Dental caries is a chronic infectious disease resulting from the penetration of oral bacteria into the enamel and dentin. Microorganisms subsequently trigger inflammatory responses in the dental pulp. These events can lead to pulp healing if the infection is not too severe following the removal of diseased enamel and dentin tissues and clinical restoration of the tooth. However, chronic inflammation often persists in the pulp despite treatment, inducing permanent loss of normal tissue and reducing innate repair capacities. For complete tooth healing the formation of a reactionary/reparative dentin barrier to distance and protect the pulp from infectious agents and restorative materials is required. Clinical and in vitro experimental data clearly indicate that dentin barrier formation only occurs when pulp inflammation and infection are minimised, thus enabling reestablishment of tissue homeostasis and health. Therefore, promoting the resolution of pulp inflammation may provide a valuable therapeutic opportunity to ensure the sustainability of dental treatments. This paper focusses on key cellular and molecular mechanisms involved in pulp responses to bacteria and in the pulpal transition between caries-induced inflammation and dentinogenic-based repair. We report, using selected examples, different strategies potentially used by odontoblasts and specialized immune cells to combat dentin-invading bacteria in vivo. PMID:26538821

  16. Advanced Implant-Prosthetic Rehabilitation: How to Obtain a Correct Restoration of Both Functions and Aesthetics in Patients with Complex Combined Dental and Maxillofacial Trauma: A Case Report and Topical Review of the Literature

    PubMed Central

    Fortunato, L.

    2017-01-01

    Aim. This study aims to explain the main steps that characterize the implant-prosthetic rehabilitation in complex combined dental and maxillofacial trauma. Material and Methods. A 20-year-old patient reported an extensive facial trauma which also involved the alveolar process of the maxillary bone. The patient reported a maxillofacial fracture and the loss of teeth 1.3, 1.2, 1.1, and 2.1. A “Le Fort” type 2 fracture was also reported, with the malar bone involvement. After reduction and containment of bone fractures, through appropriate mounting plates, appropriate functional and aesthetic rehabilitation of the patient were replaced thanks to a temporary removable prosthesis. After 6 months, the patient performed numerous clinical investigations, aimed at a proper planning of implant-prosthetic rehabilitation of the upper dental arch. Conclusion. With the planning of the case, as well as respecting the surrounding biological structures, the surgery of implants can be carried out with the most appropriate procedure. Lastly, new dental implants with highly bioactive surfaces have been developed, providing an excellent and rapid bone integration.

  17. Dental Training Films.

    ERIC Educational Resources Information Center

    Veterans Administration Medical Center, Washington, DC.

    This dental training films catalog is organized into two sections. Section I is a category listing of the films by number and title, indexed according to generalized headings; categories are as follow: anatomy, articulator systems, complete dentures, dental assisting, dental laboratory technology, dental materials, dental office emergencies,…

  18. Finding Dental Care

    MedlinePlus

    ... Finding Dental Care Where can I find low-cost dental care? Dental schools often have clinics that allow dental ... can I find more information? See Finding Low Cost Dental Care . ​​​​ WWNRightboxRadEditor2 Contact Us 1-866-232-4528 nidcrinfo@ ...

  19. Dental education and dental practice.

    PubMed Central

    Moore, J R

    1984-01-01

    This paper relates recent modes of dental practice to changes that the public and government are likely to ask the health care professions to make in the future. As usual they are asking for the best of all worlds. First, that we maintain the clinical model to the highest standards of personal dental care based and tested against the best research at our disposal, whilst we ensure there is no reduction in the high technical standards for which british dentists have a reputation. Second, that the profession is required to consider ways of providing care on the medicosocial model for the whole community at an economic level the country will afford. The broad changes in dental education have been reviewed, from the technical apprenticeship to the establishment of strong university departments in teaching hospitals. The importance of a sound biomedical foundation and of research both to education and the credibility of dental practice as a primary health care profession is stressed if the profession is to retain its position as a sister to medicine and not slide down to that of a technical ancillary. PMID:6374141

  20. Bioactive and inert dental glass-ceramics.

    PubMed

    Montazerian, Maziar; Zanotto, Edgar Dutra

    2017-02-01

    The global market for dental materials is predicted to exceed 10 billion dollars by 2020. The main drivers for this growth are easing the workflow of dentists and increasing the comfort of patients. Therefore, remarkable research projects have been conducted and are currently underway to develop improved or new dental materials with enhanced properties or that can be processed using advanced technologies, such as CAD/CAM or 3D printing. Among these materials, zirconia, glass or polymer-infiltrated ceramics, and glass-ceramics (GCs) are of great importance. Dental glass-ceramics are highly attractive because they are easy to process and have outstanding esthetics, translucency, low thermal conductivity, high strength, chemical durability, biocompatibility, wear resistance, and hardness similar to that of natural teeth, and, in certain cases, these materials are bioactive. In this review article, we divide dental GCs into the following two groups: restorative and bioactive. Most restorative dental glass-ceramics (RDGCs) are inert and biocompatible and are used in the restoration and reconstruction of teeth. Bioactive dental glass-ceramics (BDGCs) display bone-bonding ability and stimulate positive biological reactions at the material/tissue interface. BDGCs are suggested for dentin hypersensitivity treatment, implant coating, bone regeneration and periodontal therapy. Throughout this paper, we elaborate on the history, processing, properties and applications of RDGCs and BDGCs. We also report on selected papers that address promising types of dental glass-ceramics. Finally, we include trends and guidance on relevant open issues and research possibilities. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 619-639, 2017.

  1. Expanding dental hygiene to include dental therapy: improving access to care for children.

    PubMed

    Nash, David A

    2009-01-01

    Oral Health in America: A Report of the Surgeon General, and the subsequent National Call to Action to Promote Oral Health contributed significantly to raising the awareness of the American public and the dental profession regarding the lack of access to oral health care by many Americans, especially minorities and low income populations, with resulting disparities in oral health. The problem is particularly acute among children. The current workforce of dentists in the United States is inadequate to meet the oral health care needs of children in terms of numbers of dentists, as well as their distribution, ethnicity, education, and practice orientation. Dental hygienists trained in an expanded scope of practice, can help address the workforce inadequacy. Dental therapists, educated in 2-year programs of postsecondary education, comparable to America's associate degree dental hygiene programs, have been used throughout the world to provide basic, primary oral health care for children. Research has documented that utilizing dental therapists is a cost effective method of improving access to care for children. Countries that have led the way in introducing dental therapists to care for their children are now integrating their separate 2-year curriculum in dental therapy and dental hygiene into a 3-year curriculum to prepare a clinician dually trained in both dental therapy and dental hygiene. This clinician is being designated an oral health therapist. Expanding the education of dental hygienists in the United States to include skills of the internationally acclaimed dental therapist can produce oral health therapists, individuals capable of addressing the basic preventive, restorative, and minor surgical needs of children, but also able to continue to address the preventive and periodontal needs of adults.

  2. Dental repair material: a resin-modified glass-ionomer bioactive ionic resin-based composite.

    PubMed

    Croll, Theodore P; Berg, Joel H; Donly, Kevin J

    2015-01-01

    This report documents treatment and repair of three carious teeth that were restored with a new dental repair material that features the characteristics of both resin-modified glass-ionomer restorative cement (RMGI) and resin-based composite (RBC). The restorative products presented are reported by the manufacturer to be the first bioactive dental materials with an ionic resin matrix, a shock-absorbing resin component, and bioactive fillers that mimic the physical and chemical properties of natural teeth. The restorative material and base/liner, which feature three hardening mechanisms, could prove to be a notable advancement in the adhesive dentistry restorative materials continuum.

  3. [The developmental history of the dental filling materials].

    PubMed

    Gong, Yi

    2008-10-01

    Caries may cause substantial defects in the hard tissue of teeth. The dental filling for defects is an effective method to resume teeth complete form and masticatory function as well as aesthetic effects. The filling material is artificial restorative material to fill the dental defects. Tracing back the developing process of dental filling materials, we can see the advancement of stomotology of human beings. There was a revolutionary change in the filling materials from filling dental cavity with Chinese medicinal herbs to silver paste, from establishing the composition and proportion standardization of the silver amalgam filling materials to the application of new macromolecule compound resin. This is a continuous improvement and renewal in the idea and technology of dental filling treatment so that perfects the dental filling method and enables the retention of more healthy dental tissue. In addition, it pushes the development of dental aesthetics, adhesives and technology. With the improvement of people's health standard, aesthetic demands and environmental awareness, compound resin restorative materials has become clinically preferred dental filling materials of doctors and patients in clinic.

  4. Restoration Process

    NASA Technical Reports Server (NTRS)

    1979-01-01

    In the accompanying photos, a laboratory technician is restoring the once-obliterated serial number of a revolver. The four-photo sequence shows the gradual progression from total invisibility to clear readability. The technician is using a new process developed in an applications engineering project conducted by NASA's Lewis Research Center in conjunction with Chicago State University. Serial numbers and other markings are frequently eliminated from metal objects to prevent tracing ownership of guns, motor vehicles, bicycles, cameras, appliances and jewelry. To restore obliterated numbers, crime laboratory investigators most often employ a chemical etching technique. It is effective, but it may cause metal corrosion and it requires extensive preparatory grinding and polishing. The NASA-Chicago State process is advantageous because it can be applied without variation to any kind of metal, it needs no preparatory work and number recovery can be accomplished without corrosive chemicals; the liquid used is water.

  5. Dental Implant Surgery

    MedlinePlus

    Dental implant surgery Overview By Mayo Clinic Staff Dental implant surgery is a procedure that replaces tooth roots with ... look and function much like real ones. Dental implant surgery can offer a welcome alternative to dentures ...

  6. Impact of dental therapists on productivity and finances: II. Federally Qualified Health Centers.

    PubMed

    Beazoglou, Tryfon J; Bailit, Howard L; DeVitto, Judy; McGowan, Taegen; Myne-Joslin, Veronica

    2012-08-01

    This article estimates the impact of dental therapists treating children on Federally Qualified Health Center (FQHC) dental clinic finances and productivity. The analysis is based on twelve months of patient visit and financial data from large FQHC dental clinics (multiple delivery sites) in Connecticut and Wisconsin. Assuming dental therapists provide restorative, extraction, and pulpal services and dental hygienists continue to deliver all hygiene services, the maximum reduction in costs is about 6 percent. The limited impact of dental therapists on FQHC dental clinic finances is because 1) dental therapists only account for 17 percent of children services and 2) dentists are responsible for only 25 percent of clinic expenses and cost reductions are related to the difference between dental therapist and dentist wage rates.

  7. Dental Holography

    NASA Astrophysics Data System (ADS)

    Dirtoft, Ingegerd

    1983-12-01

    Ten years have passed since the first articles appeared in this new field. The qualities of the laser light together with the need of contactless 3-D measurements for different dental purposes seemed to be extremely promising, but still just a few scientists have used the method and mostly for laboratory studies. For some reason there has been a preponderance for orthodontic measurements. This seems to be a bit peculiar from holographic view compared with measurements for engineering purposes, which usually are made on metals. So naturally holography can become a clinical tool for measurements in the field of fixed bridges, removable partial dentures and implants. One of the problems is that the need for holography in dental research must be fulfilled in collaboration with physicists. Only a two-way communication during an entire experiment can balance both technical and odontological demands and thus give practical and clinical important results. The need for an easy way of handling the evaluation to get all required information is another problem and of course the holographic equipment must be converted to a box easy to handle for everyone. At last the position of dental holography today is going to be carefully examined together with an attempt to look into the hopefully exciting and not to utopic future for this research field.

  8. Intelligent dental identification system (IDIS) in forensic medicine.

    PubMed

    Chomdej, T; Pankaow, W; Choychumroon, S

    2006-04-20

    This study reports the design and development of the intelligent dental identification system (IDIS), including its efficiency and reliability. Five hundred patients were randomly selected from the Dental Department at Police General Hospital in Thailand to create a population of 3000 known subjects. From the original 500 patients, 100 were randomly selected to create a sample of 1000 unidentifiable subjects (400 subjects with completeness and possible alterations of dental information corresponding to natural occurrences and general dental treatments after the last clinical examination, such as missing teeth, dental caries, dental restorations, and dental prosthetics, 100 subjects with completeness and no alteration of dental information, 500 subjects with incompleteness and no alteration of dental information). Attempts were made to identify the unknown subjects utilizing IDIS. The use of IDIS advanced method resulted in consistent outstanding identification in the range of 82.61-100% with minimal error 0-1.19%. The results of this study indicate that IDIS can be used to support dental identification. It supports not only all types of dentitions: primary, mixed, and permanent but also for incomplete and altered dental information. IDIS is particularly useful in providing the huge quantity and redundancy of related documentation associated with forensic odontology. As a computerized system, IDIS can reduce the time required for identification and store dental digital images with many processing features. Furthermore, IDIS establishes enhancements of documental dental record with odontogram and identification codes, electrical dental record with dental database system, and identification methods and algorithms. IDIS was conceptualized based on the guidelines and standards of the American Board of Forensic Odontology (ABFO) and International Criminal Police Organization (INTERPOL).

  9. Influence of private practice employment of dental therapists in Saskatchewan on the future supply of dental therapists in Canada.

    PubMed

    Uswak, Gerry; Keller-Kurysh, Emory

    2012-08-01

    The profession of dental therapy has long been held up as a model for reducing access to care barriers in high-risk, underserved populations worldwide. Dental therapists practice in many countries delivering preventive and basic restorative care to children and adults. In North America, dental therapy education and practice date back to 1972 with the establishment of training programs at the National School of Dental Therapy in Fort Smith, Northwest Territories, and the Wascana Institute of Applied Arts and Science in Regina, Saskatchewan, as a means of reducing access to care barriers in Canada's northern territories and to implement the Saskatchewan Health Dental Plan, respectively. At present, dental therapy in North America has reached a crossroads: in the United States, the profession is cautiously being explored as a solution for improving access to care in at-risk populations. In 2011, Canada's sole training program, the National School of Dental Therapy in Prince Albert, Saskatchewan, closed when the federal government eliminated its funding. This article examines the impact of private practice employment of dental therapists in Saskatchewan on the supply of dental therapist human resources for health in Canada's three northern territories (Northwest Territories, Nunavut, and Yukon), its role in the closure of the National School of Dental Therapy in 2011, and ramifications for the future of dental therapy in Canada.

  10. Risk factors for dental caries in children with developmental disabilities.

    PubMed

    Braúna, Ana Paula Vasques Sales; Abreu, Mauro Henrique Nogueira Guimarães de; Resende, Vera Lúcia Silva; Castilho, Lia Silva de

    2016-06-14

    The aim of the present study was to investigate risk factors for dental caries in children with developmental disabilities who were treated at a clinical reference service for patients with special needs in Belo Horizonte, MG, Brazil. This is a retrospective cohort study that evaluated 401 dental charts of individuals without dental caries or restorations in their first dental appointment. The dependent variable was the time of occurrence of new dental caries or restorations and was measured in months. Gender, age, International Code of Diseases (ICD), mother´s education, sugar consumption, use of fluoride toothpaste, oral hygiene, mouth breathing, reports of xerostomia, gingival status, use of psychotropic or asthma drugs, and history of asthma were covariates. The Cox proportional hazards regression model was used to estimate the raw and adjusted hazard ratios and their respective 95% confidence intervals. The average time that individuals remained free of dental caries/restoration was equal to 107.46 months (95%CI 95.41 to 119.51), with a median of caries-free children up to 94 months. For each point increase in the scale of sucrose consumption, the increase in caries risk was 1.07 (95%CI 1.01 to 1.15). Sucrose consumption was the only risk factor for dental caries found in this group of individuals with developmental disabilities.

  11. Surgical lasers and hard dental tissue.

    PubMed

    Parker, S

    2007-04-28

    The cutting of dental hard tissue during restorative procedures presents considerable demands on the ability to selectively remove diseased carious tissue, obtain outline and retention form and maintain the integrity of supporting tooth tissue without structural weakening. In addition, the requirement to preserve healthy tissue and prevent further breakdown of the restoration places the choice of instrumentation and clinical technique as prime factors for the dental surgeon. The quest for an alternative treatment modality to the conventional dental turbine has been, essentially, patient-driven and has led to the development of various mechanical and chemical devices. The review of the literature has endorsed the beneficial effects of current laser machines. However utopian, there is additional evidence to support the development of ultra-short (nano- and femto-second) pulsed lasers that are stable in use and commercially viable, to deliver more efficient hard tissue ablation with less risk of collateral thermal damage. This paper explores the interaction of laser energy with dental hard tissues and bone and the integration of current laser wavelengths into restorative and surgical dentistry.

  12. Fracture analysis of randomized implant-supported fixed dental prostheses

    PubMed Central

    Esquivel-Upshaw, Josephine F.; Mehler, Alex; Clark, Arthur E.; Neal, Dan; Anusavice, Kenneth J.

    2014-01-01

    Objective Fractures of posterior fixed dental all-ceramic prostheses can be caused by one or more factors including prosthesis design, flaw distribution, direction and magnitude of occlusal loading, and nature of supporting infrastructure (tooth root/implant), and presence of adjacent teeth. This clinical study of implant-supported, all-ceramic fixed dental prostheses, determined the effects of (1) presence of a tooth distal to the most distal retainer; (2) prosthesis loading either along the non-load bearing or load bearing areas; (3) presence of excursive contacts or maximum intercuspation contacts in the prosthesis; and (4) magnitude of bite force on the occurrence of veneer ceramic fracture. Methods 89 implant-supported FDPs were randomized as either a three-unit posterior metal-ceramic (Au-Pd-Ag alloy and InLine POM, Ivoclar, Vivadent) FDP or a ceramic-ceramic (ZirCAD and ZirPress, Ivoclar, Vivadent) FDP. Two implants (Osseospeed, Dentsply) and custom abutments (Atlantis, Dentsply) supported these FDPs, which were cemented with resin cement (RelyX Universal Cement). Baseline photographs were made with markings of teeth from maximum intercuspation (MI) and excursive function. Patients were recalled at 6 months and 1 to 3 years. Fractures were observed, their locations recorded, and images compared with baseline photographs of occlusal contacts. Conclusion No significant relationship exists between the occurrence of fracture and: (1) the magnitude of bite force; (2) a tooth distal to the most distal retainer; and (3) contacts in load-bearing or non-load-bearing areas. However, there was a significantly higher likelihood of fracture in areas with MI contacts only. Clinical Significance This clinical study demonstrates that there is a need to evaluate occlusion differently with implant-supported prostheses than with natural tooth supported prostheses because of the absence of a periodontal ligament. Implant supported prostheses should have minimal occlusion and

  13. Choice of a dental implant system.

    PubMed

    Hunt, Peter R; Gartner, Judith L; Norkin, Frederic J

    2005-04-01

    Many dentists are bewildered by the intricacies and complexities of dental implants. They are constantly besieged by product advertisements and can find it difficult to choose which systems to work with. Some dentists are so intimidated by the subject that they choose to avoid getting involved with implants and instead stick to traditional tooth replacement systems. By breaking implants down into 4 main components, the body, collar, connection, and restorative post, it is easier to understand the structure and function of dental implants. Each portion should be designed to achieve certain objectives. Once these structural components are understood, it is easier to compare and contrast differing implant systems.

  14. Child Indicators: Dental Health.

    ERIC Educational Resources Information Center

    Lewit, Eugene M.; Kerrebrock, Nancy

    1998-01-01

    Reviews measures of dental health in children and the evidence on child dental health. Although children's dental health has improved over the past two decades, many poor children do not receive necessary dental health services, and reasons for this failure are summarized. (SLD)

  15. Restorative dentistry for the pediatric patient.

    PubMed

    Hackmyer, Steven P; Donly, Kevin J

    2010-11-01

    The American Academy of Pediatric Dentistry sponsored the Pediatric Restorative Dentistry Consensus Conference in 2002. This paper will review the consensus statements that were issued as a result of the conference. Since the conference there have been advances in procedures, materials, and techniques that need to be considered in terms of some of the consensus statements. The introduction of the First Dental Home, interim therapeutic restoration and nanotechnology are examples of some of the materials and techniques that are now part of everyday pediatric dentistry. This paper will discuss the updates as it relates to each of the 2002 consensus statements.

  16. Computer-assisted design/computer-assisted manufacturing systems: A revolution in restorative dentistry.

    PubMed

    Sajjad, Arbaz

    2016-01-01

    For the better part of the past 20 years, dentistry has seen the development of many new all-ceramic materials and restorative techniques fueled by the desire to capture the ever elusive esthetic perfection. This has resulted in the fusion of the latest in material science and the pen ultimate in computer-assisted design/computer-assisted manufacturing (CAD/CAM) technology. This case report describes the procedure for restoring the esthetic appearance of both the left and right maxillary peg-shaped lateral incisors with a metal-free sintered finely structured feldspar ceramic material using the latest laboratory CAD/CAM system. The use of CAD/CAM technology makes it possible to produce restorations faster with precision- fit and good esthetics overcoming the errors associated with traditional ceramo-metal technology. The incorporation of this treatment modality would mean that the dentist working procedures will have to be adapted in the methods of CAD/CAM technology.

  17. Weaker dental enamel explains dental decay.

    PubMed

    Vieira, Alexandre R; Gibson, Carolyn W; Deeley, Kathleen; Xue, Hui; Li, Yong

    2015-01-01

    Dental caries continues to be the most prevalent bacteria-mediated non-contagious disease of humankind. Dental professionals assert the disease can be explained by poor oral hygiene and a diet rich in sugars but this does not account for caries free individuals exposed to the same risk factors. In order to test the hypothesis that amount of amelogenin during enamel development can influence caries susceptibility, we generated multiple strains of mice with varying levels of available amelogenin during dental development. Mechanical tests showed that dental enamel developed with less amelogenin is "weaker" while the dental enamel of animals over-expressing amelogenin appears to be more resistant to acid dissolution.

  18. Dental education in Colombia

    PubMed Central

    Jaramillo, Jorge A.; Pulido, Jairo H. Ternera; Núñez, Jaime A. Castro; Bird, William F.; Komabayashi, Takashi

    2014-01-01

    This article describes Colombia's development of formal dentistry, its dental school system, curriculum, and dental licensure, and current issues in oral health care. In 1969, there were only 4 dental schools in Colombia; at this writing there are 21. Five dental schools are public and the other 16 are private. Nearly all classes are conducted in Spanish. Undergraduate pre-dental coursework is not a prerequisite for dental school in Colombia. To obtain licensure, Colombian dental students must complete 5 years of study in dental school, earn a diploma, and work for the government for 1 year. There are approximately 41,400 dentists in Colombia, and the number is increasing quickly. However, the unemployment rate among dentists is very high, even though graduation from dental school is extremely difficult. Although the 1,100:1 ratio of citizens to dentists is considered satisfactory, access to dental care is limited due to the high rate of poverty. PMID:20339245

  19. Atypical Forensic Dental Identifications.

    PubMed

    Cardoza, Anthony R; Wood, James D

    2015-06-01

    Forensic dental identification specialists are typically the last conventional option for postmortem identification. Forensic dental identification is most often accomplished by comparing radiographs of the decedent's teeth with the dental radiographs obtained from the dentist of the suspected victim. Unfortunately, antemortem dental radiographs are not always available. When presented with this challenge, the authors of this article have been successful in completing identifications using means other than dental radiographic comparison.

  20. Surface characteristic changes of dental ceramics after cyclic immersion in acidic agents and titratable acidity.

    PubMed

    Junpoom, Peerapong; Kukiattrakoon, Boonlert; Hengtrakool, Chanothai

    2010-12-01

    The potential erosive effect of acidic food, sour fruits and drinks on all-ceramic restorations used in dentistry has not been clearly documented. Surface characteristic changes have been evaluated and compared for disc-shaped specimens (diameter 12.0 mm and thickness 2.0 mm) of fluorapatite-leucite and fluorapatite ceramics using various storage agents (deionized water, citrate buffer solution, pineapple juice, green mango juice, cola soft drink and 4% acetic acid). Immersion in pineapple juice, green mango juice, cola soft drink and 4% acetic acid for 16 hours produce significant increases in surface roughness for both types of ceramics investigated.

  1. Three-dimensional imaging and guided surgery for dental implants.

    PubMed

    Ganz, Scott D

    2015-04-01

    Clinicians worldwide are increasingly adopting guided surgical applications for dental implants. Clinicians are becoming more aware of the benefits of proper planning through advanced imaging modalities and interactive treatment planning applications. All aspects of the planning phase are based on sound surgical and restorative fundamentals. As an integral part of the implant team, dental laboratories have now moved from analog to the digital world, providing the necessary support to the new digital workflow.

  2. Current aspects of restoring traumatically fractured teeth.

    PubMed

    Krastl, Gabriel; Filippi, Andreas; Zitzmann, Nicola U; Walter, Clemens; Weiger, Roland

    2011-01-01

    Endodontic and restorative considerations are of primary significance in the treatment of tooth fractures. Since exposed dentinal tubules permit invasion of bacteria into the endodontic system, a protective dressing must be applied as part of the emergency treatment. Provided the dentin wound has been sealed, restorative treatment can also be carried out at a later stage. The fractured tooth fragment can be reattached using adhesive protocols in order to restore function and esthetic appearance. If reattachment is difficult or impossible, eg, in cases of multiple or missing fragments, current composite materials enable excellent esthetic results. Minimally-invasive direct composite restorations are preferred over the more invasive indirect restorations, at least in immature teeth with an extensive coronal pulp dimension. Restorative treatment of crown-root fractures is frequently demanding due to inaccessible subgingival fracture margins. Extrusion of the remaining root is an alternative method to surgical crown lengthening for re-establishing the biological width. This can be carried out either orthodontically (forced eruption), or surgically (intra-alveolar transplantation). Although the treatment of crown-root fractures is one of the most technically sensitive procedures in dental traumatology and is frequently considered as a long-term temporary restoration, tooth conservation up to the age at which implants can be placed may be regarded as a success.

  3. Abrasive Wear of Four Direct Restorative Materials by Standard and Whitening Dentifrices

    DTIC Science & Technology

    2013-06-01

    creating cervical lesions and altering tooth surface is an area of interest in the dental community . This has led to the development of a number of...study of root caries : baseline and incidenc data. Journal of Dental Restorations, 64(9), 1141-1144. Barnes, D., Blank, L., Gingell, J., & Gilner, P... Community Dental Oral Epidemiology, 7(1), 57-64. Bull, W. H., Callender, R. M., Pugh, B. R., & Wood, G. D. (1968). The abrasion and cleaning

  4. Issues in financing dental care for the elderly.

    PubMed

    Jones, J A; Adelson, R; Niessen, L C; Gilbert, G H

    1990-01-01

    The elderly make up an increasingly larger segment of the patient population in dental practices. This article reviews recent epidemiologic, demographic, and health services research, and concludes that significant segments of the elderly are at high risk for oral disease and/or limited access to dental treatment, and consequently warrant classification as high-risk groups for policy considerations. It then proposes policy options to the dental community and public decision makers. Oral care can be viewed as having three components. Two basic components are the primary care component--which includes diagnostic, preventive restorative, and periodontal care--and the acute care component--i.e., the treatment of oral pain, trauma, and infection. The third, rehabilitative component, has to do with the restoration of oral function, including prosthodontics and cosmetic dentistry. Viewing dental care in this perspective may help link funding for dental primary care services with that for other primary health services, and link restoration of function and improvement of quality of life with similar health services, like hearing, vision, and social services. In addition, approaching dental care policy makers on several levels--i.e., federal, state, and local--will contribute to our ability as a profession, in the decades ahead, to meet the oral health needs of more elders: including the frail, those at high risk for oral disease, and those with limited access to care.

  5. Dental emergency rates at two expeditionary medical support facilities supporting operations enduring and Iraqi Freedom.

    PubMed

    Dunn, William J; Langsten, Robert E; Flores, Salvador; Fandell, Jay E

    2004-07-01

    This study reports dental emergency rates and distribution of causes of dental emergencies at two expeditionary medical support facilities supporting operations Enduring Freedom/ Iraqi Freedom. A retrospective cohort analysis of 9948 soldiers deployed to Prince Sultan Air Base, Kingdom of Saudi Arabia, and 1467 soldiers at Baghdad International Airport, Iraq, was accomplished from a phased deployment from January 2003 to September 2003. Procedures were divided into 11 categories: endodontic, extraction of teeth other than third molars, extraction of third molar teeth, restoration of teeth (caries), restoration of broken teeth (not caries), orthodontic bracket/wire problem, sensitive teeth, temperomandibular pain, periodontal, oral pathology, and prosthodontic. The dental emergency rates for Prince Sultan Air Base and Baghdad International Airport were 153 and 145 dental emergencies per 1000 soldiers per year, respectively. Most of the emergencies were because of dental caries. Pain from third molars was the second most common reason for visiting the dental clinic.

  6. Galvanic gold plating for fixed dental prosthesis.

    PubMed

    Ozcelik, Tuncer Burak; Yilmaz, Burak

    2013-07-01

    Metal ceramic partial fixed dental prostheses have been commonly used for the replacement of missing teeth for many years. Because of an increase in the price of gold, base metal alloys have been the choice of alloy for the fabrication of metal ceramic restorations in many dental clinics. Some major disadvantages of base metals are their corrosion and the dark coloration they may cause at the crown margins. This article describes a galvanic gold-plating technique, which is used to minimize corrosion and improve the esthetics of metal ceramic restorations fabricated with Cr-Co base metal alloys. This technique involves the deposition of a 6 μm to 8 μm 24 K gold layer directly onto the Cr-Co cast prosthesis framework. The technique improves metal surface properties, making them more biocompatible and usable, however, requires additional equipment and experienced laboratory technicians. Clinical studies should be performed to corroborate the long term success of this technique.

  7. Biologic restoration of primary anterior teeth: a case report.

    PubMed

    Mandroli, P S

    2003-09-01

    Restoration of primary maxillary incisors, severely destroyed by trauma or caries is a commonly faced problem in a Pediatric dental clinic. Most cases are observed in children with early childhood caries. In the past, the only option would have been to extract the affected teeth and replace them with prosthetic substitutes. However, the availability of natural crowns and roots would allow the use of biologic restorations to preserve the integrity of patient's natural dentition as presented in this case report.

  8. Diagnostic imaging for dental implant therapy.

    PubMed

    Nagarajan, Aishwarya; Perumalsamy, Rajapriya; Thyagarajan, Ramakrishnan; Namasivayam, Ambalavanan

    2014-01-01

    Dental implant is a device made of alloplastic (foreign) material implanted into the jaw bone beneath the mucosal layer to support a fixed or removable dental prosthesis. Dental implants are gaining immense popularity and wide acceptance because they not only replace lost teeth but also provide permanent restorations that do not interfere with oral function or speech or compromise the self-esteem of a patient. Appropriate treatment planning for replacement of lost teeth is required and imaging plays a pivotal role to ensure a satisfactory outcome. The development of pre-surgical imaging techniques and surgical templates helps the dentist place the implants with relative ease. This article focuses on various types of imaging modalities that have a pivotal role in implant therapy.

  9. Examining the cost-effectiveness of early dental visits.

    PubMed

    Lee, Jessica Y; Bouwens, Thomas J; Savage, Matthew F; Vann, William F

    2006-01-01

    The subject of early dental visits as an integral dimension of anticipatory guidance and the related supporting scientific evidence for this concept is a critical and timely issue for the dental profession. The purpose of this paper was to review the scientific evidence and rationale for early dental visits. In theory, early dental visits can prevent disease and reduce costs. During the age 1 dental visit, there is strong emphasis on prevention and parents are given: (1) counseling on infant oral hygiene; (2) home and office-based fluoride therapies; (3) dietary counseling; and (4) information relative to oral habits and dental injury prevention. There is evidence that the early preventive visits can reduce the need for restorative and emergency care, therefore reducing dentally related costs among high-risk children. Preschool Medicaid children who had an early preventive dental visit by age 1 were more likely to use subsequent preventive services and experienced less dentally related costs. These finding have significant policy implications, and more research is needed to examine this effect in a low-risk population.

  10. Standards, Regulation and Registration of Dental Laboratories. An Industry Update.

    PubMed

    Giovannone, Paul L

    2015-01-01

    State dental associations are showing increased interest in maintaining current standards and regulations affecting the dental laboratory industry as mandated by the Food and Drug Administration. The domestic dental laboratory industry is being significantly stressed by foreign competition, rapid technology development and unprecedented consolidation, which are changing the way that prosthetic devices and restorations are manufactured and delivered to dentists. Of paramount importance to the prescribing dentist is the accurate documentation of the source and materials being used in prostheses being delivered to patients.

  11. Dental caries: an updated medical model of risk assessment.

    PubMed

    Kutsch, V Kim

    2014-04-01

    Dental caries is a transmissible, complex biofilm disease that creates prolonged periods of low pH in the mouth, resulting in a net mineral loss from the teeth. Historically, the disease model for dental caries consisted of mutans streptococci and Lactobacillus species, and the dental profession focused on restoring the lesions/damage from the disease by using a surgical model. The current recommendation is to implement a risk-assessment-based medical model called CAMBRA (caries management by risk assessment) to diagnose and treat dental caries. Unfortunately, many of the suggestions of CAMBRA have been overly complicated and confusing for clinicians. The risk of caries, however, is usually related to just a few common factors, and these factors result in common patterns of disease. This article examines the biofilm model of dental caries, identifies the common disease patterns, and discusses their targeted therapeutic strategies to make CAMBRA more easily adaptable for the privately practicing professional.

  12. Adhesion of Dental Materials to Tooth Structure

    NASA Astrophysics Data System (ADS)

    Mitra, Sumita B.

    2000-03-01

    The understanding and proper application of the principles of adhesion has brought forth a new paradigm in the realm of esthetic dentistry. Modern restorative tooth procedures can now conserve the remaining tooth-structure and also provide for the strengthening of the tooth. Adhesive restorative techniques call for the application and curing of the dental adhesive at the interface between the tooth tissue and the filling material. Hence the success of the restoration depends largely on the integrity of this interface. The mechanism of adhesion of the bonding materials to the dental hard tissue will be discussed in this paper. There are four main steps that occur during the application of the dental adhesive to the oral hard tissues: 1) The first step is the creation of a microstructure in the tooth enamel or dentin by means of an acidic material. This can be through the application of a separate etchant or can be accomplished in situ by the adhesive/primer. This agent has to be effective in removing or modifying the proteinaceous “smear” layer, which would otherwise act as a weak boundary layer on the surface to be bonded. 2) The primer/adhesive must then be able to wet and penetrate the microstructure created in the tooth. Since the surface energies of etched enamel and that of etched dentin are different finding one material to prime both types of dental tissues can be quite challenging. 3) The ionomer types of materials, particularly those that are carboxylate ion-containing, can chemically bond with the calcium ions of the hydroxyapatite mineral. 4) Polymerization in situ allows for micromechanical interlocking of the adhesive. The importance of having the right mechanical properties of the cured adhesive layer and its role in absorbing and dissipating stresses encountered by a restored tooth will also be discussed.

  13. Dental fillings in Civil War skulls: what do they tell us?

    PubMed

    Glenner, R A; Willey, P; Sledzik, P S; Junger, E P

    1996-11-01

    This article discusses the dental techniques, methods and materials used in the South during the Civil War based on the dental restorations found in the skulls of four confederate soldiers. The skulls display a variety of dental filling materials, including thorium, lead, tin and tin amalgam. These materials were used at a time when more valuable materials, such as gold and silver, were not readily available in the South.

  14. Japanese research and development on metallic biomedical, dental, and healthcare materials

    NASA Astrophysics Data System (ADS)

    Niinomi, Mitsuo; Hanawa, Takao; Narushima, Takayuki

    2005-04-01

    There is considerable demand for metallic materials for use in medical and dental devices. Metals and alloys are widely used as biomedical materials and are indispensable in the medical field. In dentistry, metal is used for restorations, orthodontic wires, and dental implants. This article describes R&D on metallic biomaterials primarily conducted by the members of the Japan Institute of Metals.

  15. Tooth-colored CAD/CAM monolithic restorations.

    PubMed

    Reich, S

    2015-01-01

    A monolithic restoration (also known as a full contour restoration) is one that is manufactured from a single material for the fully anatomic replacement of lost tooth structure. Additional staining (followed by glaze firing if ceramic materials are used) may be performed to enhance the appearance of the restoration. For decades, monolithic restoration has been the standard for inlay and partial crown restorations manufactured by both pressing and computer-aided design and manufacturing (CAD/CAM) techniques. A limited selection of monolithic materials is now available for dental crown and bridge restorations. The IDS (2015) provided an opportunity to learn about and evaluate current trends in this field. In addition to new developments, established materials are also mentioned in this article to complete the picture. In line with the strategic focus of the IJCD, the focus here is naturally on CAD/CAM materials.

  16. Biological restoration in pediatric dentistry: a brief insight.

    PubMed

    Md, Indira; Singh Dhull, Kanika; Nandlal, B; Kumar Ps, Praveen; Singh Dhull, Rachita

    2014-01-01

    Dental caries is the most prevalent disease in humans, especially during early childhood. The restoration of such an extensive carious lesion should be done properly to reestablish their anatomy and hence their masticatory, phonetic, esthetic and space-maintainer functions in the dental arches. The consequences of premature loss of primary teeth are well known, namely the loss of vertical dimension of occlusion, tongue thrusting and mouth breathing habits, which can be the sources of future malocclusion. Satisfactory restoration of these teeth, improving esthetics, along with the management of space and function has always been a challenge for pediatric dentist. An ever increasing demand for esthetics has led to innovation and development of newer treatment modalities for these problems. In an attempt to widen the treatment options as biologically and conservatively as possible, tooth structure is used as a restorative material to rehabilitate severely destroyed tooth crowns. This technique consists of bonding sterile dental fragments, obtained either from the patient or from a tooth bank, to the teeth. Such a technique was termed as 'biological restoration'. This article aims at reviewing the evolution, techniques and outcome of such biological restorations. How to cite this article: MD Indira, Dhull KS, Nandlal B, Kumar PSP, Dhull RS. Biological Restoration in Pediatric Dentistry: A Brief Insight. Int J Clin Pediatr Dent 2014;7(3):197-201.

  17. [Currently Recommended Restorative Materials in Modern Conservative Dentistry].

    PubMed

    Kobierska-Brzoza, Joanna Monika; Dobrzyński, Maciej; Fita, Katarzyna Agnieszka; Bader-Orłowska, Dorota; Szymonowicz, Maria

    2015-01-01

    Conservative treatment which restores the function, aesthetics and protects remaining tooth structure, and what is the most important, the viability of the tooth pulp, is still needed. Dental fillings replace specialized tissues of the tooth that have been lost due to caries or injury. Any decision concerning the use of a particular restorative material should be individualized and based on the competence regarding the composition, properties and characteristics of the specific restorative material. This requires continuous updating of knowledge about available dental materials as well as education of patients who, according to actual models of dental care, should be active partners in the therapeutic process. The selection of restorative materials is often related to financial abilities of the patients, and more generally to the economic model of organized health care in a particular country. Nowadays, amalgam is increasingly dislodged by adhesive materials which permit to save more tooth structure and allow to preserve natural teeth for a longer time. In the nearest future we can expect further development of minimally invasive techniques and improvements of restorative materials, especially their mechanical properties like strength and wear resistance as well as biocompatibility. The article presents restorative materials used in modern dentistry.

  18. The Use of Quaternary Ammonium to Combat Dental Caries

    PubMed Central

    Ge, Yang; Wang, Suping; Zhou, Xuedong; Wang, Haohao; Xu, Hockin H. K.; Cheng, Lei

    2015-01-01

    Resin composites and adhesives are increasingly popular in dental restorations, but secondary caries is one of the main reasons for restoration failure. Quaternary ammonium monomers (QAMs) have an anti-microbial effect and are widely used in many fields. Since the concept of the immobilized antibacterial effect was put forward, dental restorations containing QAMs have been studied to reduce secondary caries. Previous studies have been struggling to develop novel anti-caries materials which might have triple benefits: good mechanical properties, antibacterial effects and remineralization potentials. Different kinds of QAMs have been proven to be effective in inhibiting the growth and metabolism of biofilms. Combination of QAMs and other nanoparticles in resin composites and adhesives could enhance their anti-caries capability. Therefore, QAMs are promising to show significant impact on the future of restorative and preventive dentistry. PMID:26635932

  19. Bonding of restorative materials to dentin with various luting agents.

    PubMed

    Peutzfeldt, A; Sahafi, A; Flury, S

    2011-01-01

    The aim was to compare eight types of luting agents when used to bond six indirect, laboratory restorative materials to dentin. Cylinders of the six restorative materials (Esteticor Avenir [gold alloy], Tritan [titanium], NobelRondo [feldspathic porcelain], Finesse All-Ceramic [leucite-glass ceramic], Lava [zirconia], and Sinfony [resin composite]) were ground and air-abraded. Cylinders of feldspathic porcelain and glass ceramic were additionally etched with hydrofluoric acid and were silane-treated. The cylinders were luted to ground human dentin with eight luting agents (DeTrey Zinc [zinc phosphate cement], Fuji I [conventional glass ionomer cement], Fuji Plus [resin-modified glass ionomer cement], Variolink II [conventional etch-and-rinse resin cement], Panavia F2.0 and Multilink [self-etch resin cements], and RelyX Unicem Aplicap and Maxcem [self-adhesive resin cements]). After water storage at 37°C for one week, the shear bond strength of the specimens (n=8/group) was measured, and the fracture mode was stereomicroscopically examined. Bond strength data were analyzed with two-factorial analysis of variance (ANOVA) followed by Newman-Keuls' Multiple Range Test (α=0.05). Both the restorative material and the luting agent had a significant effect on bond strength, and significant interaction was noted between the two variables. Zinc phosphate cement and glass ionomer cements produced the lowest bond strengths, whereas the highest bond strengths were found with the two self-etch and one of the self-adhesive resin cements. Generally, the fracture mode varied markedly with the restorative material. The luting agents had a bigger influence on bond strength between restorative materials and dentin than was seen with the restorative material.

  20. Dental Auxiliary Occupations. Interim Report.

    ERIC Educational Resources Information Center

    Kingston, Richard D.

    As part of a dental auxiliaries project, a Dental Auxiliary National Technical Advisory Committee was established, and its major undertaking was to assist in the development of a functional inventory for each of the three dental auxiliary occupations (dental assisting, dental hygiene, and dental laboratory technology). The analysis consisted of…

  1. Development of Ag-Pd-Au-Cu alloys for multiple dental applications. Part 2. Mechanical properties of experimental Ag-Pd-Au-Cu alloys containing Sn or Ga for ceramic-metal restorations.

    PubMed

    Goto, S; Nakai, A; Miyagawa, Y; Ogura, H

    2001-06-01

    Eighteen Ag-Pd-Au-Cu alloys, consisting of nine Ag-Pd-Au-Cu mother compositions (Pd: 20, 30 or 40%, Au: 20%, Cu: 10, 15 or 20%, Ag: balance) containing either 5% Sn or 5% Ga as an additive metal, were experimentally prepared. Tensile strength, proof stress, elongation, elastic modulus, and Vickers hardness of these alloys were evaluated to clarify the potential of these alloys for use as ceramic-metal restorations as well as the effects of the Pd and Cu contents on their mechanical properties. The tensile strength, proof stress, elongation, elastic modulus and Vickers hardness of the 18 experimental alloys were in the range of 410.0-984.0 MPa, 289.7-774.3 MPa, 2.2-23.7%, 81.3-123.0 GPa and 135.7-332.3 HV1, respectively. Ten of the 18 experimental alloys can be used for ultra-low fusing ceramics based on their proof stress, elastic modulus, elongation and hardness. Between the Ga- and Sn-added alloys, differences in tensile strength, proof stress, elongation and hardness were found at several Ag-Pd-Au-Cu compositions.

  2. Effects of Computer-Aided Manufacturing Technology on Precision of Clinical Metal-Free Restorations

    PubMed Central

    Lee, Ki-Hong; Yeo, In-Sung; Wu, Benjamin M.; Yang, Jae-Ho; Han, Jung-Suk; Kim, Sung-Hun; Yi, Yang-Jin; Kwon, Taek-Ka

    2015-01-01

    Purpose. The purpose of this study was to investigate the marginal fit of metal-free crowns made by three different computer-aided design/computer-aided manufacturing (CAD/CAM) systems. Materials and Methods. The maxillary left first premolar of a dentiform was prepared for all-ceramic crown restoration. Thirty all-ceramic premolar crowns were made, ten each manufactured by the Lava system, Cercon, and Cerec. Ten metal ceramic gold (MCG) crowns served as control. The marginal gap of each sample was measured under a stereoscopic microscope at 75x magnification after cementation. One-way ANOVA and the Duncan's post hoc test were used for data analysis at the significance level of 0.05. Results. The mean (standard deviation) marginal gaps were 70.5 (34.4) μm for the MCG crowns, 87.2 (22.8) μm for Lava, 58.5 (17.6) μm for Cercon, and 72.3 (30.8) μm for Cerec. There were no significant differences in the marginal fit among the groups except that the Cercon crowns had significantly smaller marginal gaps than the Lava crowns (P < 0.001).  Conclusions. Within the limitation of this study, all the metal-free restorations made by the digital CAD/CAM systems had clinically acceptable marginal accuracy. PMID:26557681

  3. Dental Laboratory Career Ladder (AFSC 4Y1X1)

    DTIC Science & Technology

    1994-08-01

    analysis identified one job cluster and seven jobs: Base Dental Lab cluster, Orthodontic Appliance Fabricator job, Fixed Restoration Fabricator job, Crown...reline and repair, removable partial denture construction, crown and fixed partial denture construction, fabrication of orthodontic appliances, and...CLUSTER (STG26, N=271) II. ORTHODONTIC APPLIANCE FABRICATOR JOB (STG40, N=7) III. FIXED RESTORATION FABRICATOR JOB (STG75, N=25) IV. CROWN FABRICATOR

  4. Dental Exam for Children

    MedlinePlus

    ... and thumb sucking Toddlers, school-age children and adolescents During each regular checkup, the dentist or hygienist ... dental hygienist about proper oral health care for adolescents. American Dental Hygienists' Association. http://www.adha.org/ ...

  5. About Dental Amalgam Fillings

    MedlinePlus

    ... documents in the Related Resources section. Why is mercury used in dental amalgam? Approximately half of a ... about bioaccumulation, please see Related Resources. Is the mercury in dental amalgam the same as the mercury ...

  6. Minor changes in serum levels of cytokines after removal of amalgam restorations.

    PubMed

    Björkman, Lars; Brokstad, Karl A; Moen, Ketil; Jonsson, Roland

    2012-06-01

    Dental amalgam restorations release mercury and silver which is absorbed and distributed in the body. Animal studies have shown that both elements may interfere with the host by activation of the immune system in genetically susceptible strains at exposure levels relevant to those from dental amalgam restorations. The aim of this study was to test the hypothesis of no change over time in concentrations of a number of immune mediators in serum after removal of all dental amalgam restorations in patients with health complaints attributed to their amalgam restorations and compare with a healthy reference group. Twenty patients previously examined at a specialty unit for health complaints attributed to dental materials were included in a clinical trial and had all amalgam restorations replaced with other dental restorative materials. Serum samples were collected before amalgam removal and 3 and 12 months after the removal was finished. Twenty blood donors matched for age and gender were used as comparison group. A fluorescent bead-based (Luminex) immunoassay kit was used to measure cytokines, chemokines and growth factors in serum. At baseline, the patient group had slightly higher values for GM-CSF, IL-6, IL-2R, IFN-alpha, IL-7, and IL-12p40/p70 compared with the reference group. After amalgam removal a decrease towards the median value of the reference group was found for GM-CSF, IL-8, and IL-7. In conclusion, removal of all dental amalgam restorations and replacement with other dental restorative materials was associated with decreased concentrations of Th1-type proinflammatory markers in serum.

  7. 75 FR 33169 - Dental Devices: Classification of Dental Amalgam, Reclassification of Dental Mercury, Designation...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-11

    ...-AG21 Dental Devices: Classification of Dental Amalgam, Reclassification of Dental Mercury, Designation of Special Controls for Dental Amalgam, Mercury, and Amalgam Alloy; Technical Amendment AGENCY: Food... classified dental amalgam as a class II device, reclassified dental mercury from class I to class II,...

  8. Posterior composite restoration update: focus on factors influencing form and function

    PubMed Central

    Bohaty, Brenda S; Ye, Qiang; Misra, Anil; Sene, Fabio; Spencer, Paulette

    2013-01-01

    Restoring posterior teeth with resin-based composite materials continues to gain popularity among clinicians, and the demand for such aesthetic restorations is increasing. Indeed, the most common aesthetic alternative to dental amalgam is resin composite. Moderate to large posterior composite restorations, however, have higher failure rates, more recurrent caries, and increased frequency of replacement. Investigators across the globe are researching new materials and techniques that will improve the clinical performance, handling characteristics, and mechanical and physical properties of composite resin restorative materials. Despite such attention, large to moderate posterior composite restorations continue to have a clinical lifetime that is approximately one-half that of the dental amalgam. While there are numerous recommendations regarding preparation design, restoration placement, and polymerization technique, current research indicates that restoration longevity depends on several variables that may be difficult for the dentist to control. These variables include the patient’s caries risk, tooth position, patient habits, number of restored surfaces, the quality of the tooth–restoration bond, and the ability of the restorative material to produce a sealed tooth–restoration interface. Although clinicians tend to focus on tooth form when evaluating the success and failure of posterior composite restorations, the emphasis must remain on advancing our understanding of the clinical variables that impact the formation of a durable seal at the restoration–tooth interface. This paper presents an update of existing technology and underscores the mechanisms that negatively impact the durability of posterior composite restorations in permanent teeth. PMID:23750102

  9. RADIOPACITY OF RESTORATIVE MATERIALS USING DIGITAL IMAGES

    PubMed Central

    Salzedas, Leda Maria Pescinini; Louzada, Mário Jefferson Quirino; de Oliveira, Antonio Braz

    2006-01-01

    The radiopacity of esthetic restorative materials has been established as an important requirement, improving the radiographic diagnosis. The aim of this study was to evaluate the radiopacity of six restorative materials using a direct digital image system, comparing them to the dental tissues (enamel-dentin), expressed as equivalent thickness of aluminum (millimeters of aluminum). Five specimens of each material were made. Three 2-mm thick longitudinal sections were cut from an intact extracted permanent molar tooth (including enamel and dentin). An aluminum step wedge with 9 steps was used. The samples of different materials were placed on a phosphor plate together with a tooth section, aluminum step wedge and metal code letter, and were exposed using a dental x-ray unit. Five measurements of radiographic density were obtained from each image of each item assessed (restorative material, enamel, dentin, each step of the aluminum step wedge) and the mean of these values was calculated. Radiopacity values were subsequently calculated as equivalents of aluminum thickness. Analysis of variance (ANOVA) indicated significant differences in radiopacity values among the materials (P<0.0001). The radiopacity values of the restorative materials evaluated were, in decreasing order: TPH, F2000, Synergy, Prisma Flow, Degufill, Luxat. Only Luxat had significantly lower radiopacity values than dentin. One material (Degufill) had similar radiopacity values to enamel and four (TPH, F2000, Synergy and Prisma Flow) had significantly higher radiopacity values than enamel. In conclusion, to assess the adequacy of posterior composite restorations it is important that the restorative material to be used has enough radiopacity, in order to be easily distinguished from the tooth structure in the radiographic image. Knowledge on the radiopacity of different materials helps professionals to select the most suitable material, along with other properties such as biocompatibility, adhesion and

  10. Maxillary segmental osteoperiosteal flap with simultaneous placement of dental implants: case report of a novel technique.

    PubMed

    Tsegga, Tibebu; Wright, Thomas

    2017-12-01

    Dental restorative space from the opposing dentition requires adequate distance for restorative material for an acceptable restoration. Typically, long-standing edentulous alveolar ridges will have vertical and or horizontal defects that require alveolar ridge augmentation for ideal dental implant restorations. Along with these defects, one will see the opposing dentition supra erupt which can obliterate the restorative space. Multiple surgical techniques have been described to address these dilemmas. The use of osteoperiosteal flaps has been described to address vertical height deficiencies. The purpose of this paper is to document and introduce a maxillary segmental osteoperiosteal flap intrusion to increase the restorative space with simultaneous dental implant placement. As with most dilemmas in treatment planning dental implants, multiple acceptable treatment options are available to the practitioner. This technique is another of many that can be added to the available options. When appropriately planned in select cases, this technique will result with ideal dental implant restorations without compromising the esthetic and functional harmony of the native dentition.

  11. A systematic review of CAD/CAM fit restoration evaluations.

    PubMed

    Boitelle, P; Mawussi, B; Tapie, L; Fromentin, O

    2014-11-01

    The evolution and development of CAD/CAM systems have led to the production of prosthetic reconstructions by going beyond the use of traditional techniques. Precision adjustment of prosthetic elements is considered essential to ensure sustainable restoration and dental preparation. The purpose of this article was to summarise the current literature on the fitting quality of fixed prostheses obtained by CAD/CAM technology.

  12. Common Dental Injury Management in Athletes

    PubMed Central

    Young, Eliot J.; Macias, C. Roger; Stephens, Lindsay

    2015-01-01

    Context: Orofacial and dental trauma continues to be a commonly encountered issue for the sports medicine team. All sports have some risk for dental injury, but “contact sports” presumably incur more risk. Immediate evaluation and proper management of the most common injuries to dentition can result in saving or restoration of tooth structure. Despite the growing body of evidence, mouth guard use and dental protection have not paralleled the increase in sports participation. Evidence Acquisition: A PubMed search from 1960 through April 2012 was conducted, as well as a review of peer-reviewed online publications. Results: Common dental injuries in sports include tooth (crown) fractures; tooth intrusion, extrusion, and avulsion; and temporomandibular joint dislocation. Mouth guards help prevent most injuries and do not significantly affect ventilation or speech if fitted properly. Conclusion: A working knowledge of the presentation as well as management of commonly encountered dental trauma in sports is essential to the immediate care of an athlete and returning to play. Mouth guard use should be encouraged for athletes of all ages in those sports that incur significant risk. PMID:26131303

  13. Inappropriate treatment of traumatic dental injuries.

    PubMed

    Dorney, B

    1999-08-01

    Traumatic dental injuries are emergencies that must be treated expediently and efficiently to reduce pain and to restore function and appearance. With an increase in the incidence of traumatic dental injuries in our community (I) it is essential that the dental practitioner has "up-to-date" knowledge of dental trauma. The peak incidences of injury are 2-4 years and 8-10 years of age, with statistics revealing 30% of children suffer trauma to the primary dentition, and 22% of children suffer trauma to the permanent dentition by the age of 14 (I). The male to female ratio is 2:1. Aside from the emergency treatment and clinical decisions that must be made at the time of injury there is a need for long-term follow-up because of the high incidences of complications (2, 3). The factors that will influence the extent of injury will be energy impact, the direction of the impacting object, its shape and its resilience (4). Recent articles have raised concerns about inappropriate treatment for traumatic dental injuries (5, 6). This report will look at one such case.

  14. Multiaxial analysis of dental composite materials.

    PubMed

    Kotche, Miiri; Drummond, James L; Sun, Kang; Vural, Murat; DeCarlo, Francesco

    2009-02-01

    Dental composites are subjected to extreme chemical and mechanical conditions in the oral environment, contributing to the degradation and ultimate failure of the material in vivo. The objective of this study is to validate an alternative method of mechanically loading dental composite materials. Confined compression testing more closely represents the complex loading that dental restorations experience in the oral cavity. Dental composites, a nanofilled and a hybrid microfilled, were prepared as cylindrical specimens, light-cured in ring molds of 6061 aluminum, with the ends polished to ensure parallel surfaces. The samples were subjected to confined compression loading to 3, 6, 9, 12, and 15% axial strain. Upon loading, the ring constrains radial expansion of the specimen, generating confinement stresses. A strain gage placed on the outer wall of the aluminum confining ring records hoop strain. Assuming plane stress conditions, the confining stress (sigma(c)) can be calculated at the sample/ring interface. Following mechanical loading, tomographic data was generated using a high-resolution microtomography system developed at beamline 2-BM of the Advanced Photon Source at Argonne National Laboratory. Extraction of the crack and void surfaces present in the material bulk is numerically represented as crack edge/volume (CE/V), and calculated as a fraction of total specimen volume. Initial results indicate that as the strain level increases the CE/V increases. Analysis of the composite specimens under different mechanical loads suggests that microtomography is a useful tool for three-dimensional evaluation of dental composite fracture surfaces.

  15. Accreditation in Dental Hygiene.

    ERIC Educational Resources Information Center

    National Commission on Accrediting, Washington, DC.

    The Council on Dental Education cooperates with the American Dental Hygienists' Association in developing educational requirements for schools of dental hygiene. To be eligible for accreditation, schools must operate on a non-profit basis. A school applying for accreditation completes a previsitation questionnaire concerning its program. The…

  16. Dental Manpower Fact Book.

    ERIC Educational Resources Information Center

    Ake, James N.; Johnson, Donald W.

    Statistical data on many aspects of dental and allied dental personnel supply, distribution, characteristics, and education and on certain other aspects of dental services are presented and discussed. The data on dentist supply show the national trend in the supply of active dentists since 1950 and the concurrent changes in dentist-to-population…

  17. Dental Laboratory Technology.

    ERIC Educational Resources Information Center

    Department of the Air Force, Washington, DC.

    The Air Force dental laboratory technology manual is designed as a basic training text as well as a reference source for dental laboratory technicians, a specialty occupation concerned with the design, fabrication, and repair of dental prostheses. Numerous instructive diagrams and photographs are included throughout the manual. The comprehensive…

  18. DENTAL SCHOOL PLANNING.

    ERIC Educational Resources Information Center

    GALAGAN, DONALD J.

    THIS DISCUSSION PRESENTS A COMPLETE PICTURE OF THE CURRENT STATE OF DENTAL EDUCATION WITH SUGGESTIONS FOR MEETING THE DEMANDS FOR DENTAL STAFF AND FACILITIES. THE AREAS INVESTIGATED ARE (1) OBJECTIVES IN DENTAL EDUCATION--COURSES, TEACHING MODES, INNOVATIONS IN CURRICULUM, COORDINATION OF BASIC AND CLINICAL INSTRUCTION, (2) FACILITY…

  19. Dental Assisting Laboratory Manual.

    ERIC Educational Resources Information Center

    Thiel, Sandra J.

    Compiled to introduce the dental assisting student to various techniques used in the dental office and to present theoretical information essential for the student's professional development, this laboratory guide consists of three units of instruction. The first unit is an introduction to dental assisting and contains five topics of study. The…

  20. Perspectives from Dental Research.

    ERIC Educational Resources Information Center

    Baum, Bruce J.

    1996-01-01

    This paper responds to the Institute of Medicine's 1995 report concerning the present status and future needs of dental education in the United States. It examines whether real reform is occurring at the National Institute of Dental Research, within the academic dental community, and within the practicing profession. It concludes that very little…

  1. Restoration of a large class IV fracture using direct composite resin: A clinical report.

    PubMed

    Romero, Mario F; Austin Grant, Jamie; Todd, Megan

    2017-04-03

    Restoration of anterior tooth fractures is a common dental procedure. Both direct and indirect options are clinically acceptable to repair fractured teeth. For a large class IV fracture, treatment planning is time consuming, and the artistic skills necessary to achieve optimal results can be daunting. This clinical report describes a step-by-step protocol for achieving highly esthetic direct anterior restorations.

  2. Single unit CAD/CAM restorations: a literature review.

    PubMed

    Freedman, Michael; Quinn, Frank; O'Sullivan, Michael

    2007-01-01

    Computer-aided design/computer-aided manufacture (CAD/CAM) has been used in dentistry since 1987. Since then, many CAD/CAM systems have been described, which enable the production of chair-side single unit dental restorations. These restorations are of comparable quality to those made by conventional techniques and have some specific advantages, including rapid production, improved wear properties, decreased laboratory fee and improved cross infection control. This literature review investigates the evidence base for the use of single unit CAD/CAM restorations. Materials, marginal gap, aesthetics, post-operative sensitivity, cementation, cost-effectiveness and longevity are discussed.

  3. Weaker Dental Enamel Explains Dental Decay

    PubMed Central

    Vieira, Alexandre R.; Gibson, Carolyn W.; Deeley, Kathleen; Xue, Hui; Li, Yong

    2015-01-01

    Dental caries continues to be the most prevalent bacteria-mediated non-contagious disease of humankind. Dental professionals assert the disease can be explained by poor oral hygiene and a diet rich in sugars but this does not account for caries free individuals exposed to the same risk factors. In order to test the hypothesis that amount of amelogenin during enamel development can influence caries susceptibility, we generated multiple strains of mice with varying levels of available amelogenin during dental development. Mechanical tests showed that dental enamel developed with less amelogenin is “weaker” while the dental enamel of animals over-expressing amelogenin appears to be more resistant to acid dissolution. PMID:25885796

  4. The effect of repeated firings on the color change of dental ceramics using different glazing methods

    PubMed Central

    Yılmaz, Kerem; Ozturk, Caner

    2014-01-01

    PURPOSE Surface color is one of the main criteria to obtain an ideal esthetic. Many factors such as the type of the material, surface specifications, number of firings, firing temperature and thickness of the porcelain are all important to provide an unchanged surface color in dental ceramics. The aim of this study was to evaluate the color changes in dental ceramics according to the material type and glazing methods, during the multiple firings. MATERIALS AND METHODS Three different types of dental ceramics (IPS Classical metal ceramic, Empress Esthetic and Empress 2 ceramics) were used in the study. Porcelains were evaluated under five main groups according to glaze and natural glaze methods. Color changes (ΔE) and changes in color parameters (ΔL, Δa, Δb) were determined using colorimeter during the control, the first, third, fifth, and seventh firings. The statistical analysis of the results was performed using ANOVA and Tukey test. RESULTS The color changes which occurred upon material-method-firing interaction were statistically significant (P<.05). ΔE, ΔL, Δa and Δb values also demonstrated a negative trend. The MC-G group was less affected in terms of color changes compared to other groups. In all-ceramic specimens, the surface color was significantly affected by multiple firings. CONCLUSION Firing detrimentally affected the structure of the porcelain surface and hence caused fading of the color and prominence of yellow and red characters. Compressible all-ceramics were remarkably affected by repeated firings due to their crystalline structure. PMID:25551001

  5. Dental ceramics: An update

    PubMed Central

    Shenoy, Arvind; Shenoy, Nina

    2010-01-01

    In the last few decades, there have been tremendous advances in the mechanical properties and methods of fabrication of ceramic materials. While porcelain-based materials are still a major component of the market, there have been moves to replace metal ceramics systems with all ceramic systems. Advances in bonding techniques have increased the range and scope for use of ceramics in dentistry. In this brief review, we will discuss advances in ceramic materials and fabrication techniques. Examples of the microstructure property relationships for these ceramic materials will also be addressed. PMID:21217946

  6. Design and development of self-healing dental composites.

    PubMed

    Huyang, George; Debertin, Anne E; Sun, Jirun

    2016-03-15

    The purpose of this project is to design and develop a clinically applicable self-healing dental composite (SHDC). The value of resin-based dental restorations could be improved by increasing their service lives. One way to improve longevity is to obturate micro-cracks that form during or after the composite hardens in the dental cavity. Toward this end, we introduce here a new type of SHDC made with contemporary dental components plus two additional ingredients: a healing powder (HP, strongtium fluoroaluminosilicate particles) and a healing liquid (HL, aqueous solutions of polyacrylic acids) that is enclosed within silica microcapsules. As micro-cracks develop, they will break the microcapsules in their propagation path, thereby releasing HL. This liquid will then react with particles of HP exposed by the crack formation, forming an insoluble reaction product that fills and seals the cracks. The key factors to achieve this self-healing of cracks are discussed. The elastic modulus of a SHDC appeared to be satisfactory. The healing process was confirmed by means of mechanical, morphological, and chemical methods. The SHDC restored micro-cracks without external intervention, thereby showing potential for increasing the service lives of dental restorations. Importantly, this SHDC contains only clinically-tested, biocompatible materials, making it readily applicable.

  7. Biological Restoration in Pediatric Dentistry: A Brief Insight

    PubMed Central

    MD, Indira; Nandlal, B; Kumar PS, Praveen; Singh Dhull, Rachita

    2014-01-01

    ABSTRACT% Dental caries is the most prevalent disease in humans, especially during early childhood. The restoration of such an extensive carious lesion should be done properly to reestablish their anatomy and hence their masticatory, phonetic, esthetic and space-maintainer functions in the dental arches. The consequences of premature loss of primary teeth are well known, namely the loss of vertical dimension of occlusion, tongue thrusting and mouth breathing habits, which can be the sources of future malocclusion. Satisfactory restoration of these teeth, improving esthetics, along with the management of space and function has always been a challenge for pediatric dentist. An ever increasing demand for esthetics has led to innovation and development of newer treatment modalities for these problems. In an attempt to widen the treatment options as biologically and conservatively as possible, tooth structure is used as a restorative material to rehabilitate severely destroyed tooth crowns. This technique consists of bonding sterile dental fragments, obtained either from the patient or from a tooth bank, to the teeth. Such a technique was termed as ‘biological restoration’. This article aims at reviewing the evolution, techniques and outcome of such biological restorations. How to cite this article: MD Indira, Dhull KS, Nandlal B, Kumar PSP, Dhull RS. Biological Restoration in Pediatric Dentistry: A Brief Insight. Int J Clin Pediatr Dent 2014;7(3):197-201. PMID:25709301

  8. 21 CFR 872.4200 - Dental handpiece and accessories.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Dental handpiece and accessories. 872.4200 Section 872.4200 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... restorations, such as fillings, and for cleaning teeth. (b) Classification. Class I....

  9. 21 CFR 872.3640 - Endosseous dental implant.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Endosseous dental implant. 872.3640 Section 872.3640 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... for prosthetic devices, such as artificial teeth, in order to restore a patient's chewing function....

  10. 21 CFR 872.4200 - Dental handpiece and accessories.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Dental handpiece and accessories. 872.4200 Section 872.4200 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... restorations, such as fillings, and for cleaning teeth. (b) Classification. Class I....

  11. 21 CFR 872.4200 - Dental handpiece and accessories.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Dental handpiece and accessories. 872.4200 Section 872.4200 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... restorations, such as fillings, and for cleaning teeth. (b) Classification. Class I....

  12. Forty years of research--its impact on dental practice.

    PubMed

    Mandel, I D

    1989-03-01

    With the multiple use of fluorides the philosophical basis of dental practice shifted from the restoration of the dentition to the prevention of the initiation of dental disease. In the United States, the profound impact on caries in children, with 50 per cent of the 5-17 year olds caries-free, has changed the relative distribution of the various dental services and the pattern of dental care. The child orientation has been superceded by greater attention to the restorative and other needs of the middle-aged and geriatric population. The research-generated insights into the role of plaque in the periodontal diseases and the wide-scale efforts to improve oral hygiene via plaque control have resulted in a marked reduction in gingivitis and manageable levels of periodontis in the employed population below the age of 65. More advanced disease can be treated more effectively because of new diagnostic procedures and new technologies as well as the use of anti-bacterial and anti-inflammatory agents. Major research advances in oral biology, oral medicine and oral diagnosis have extended both the depth and breadth of preventive dental practice. The scope of preventive dentistry now goes well beyond caries and periodontal disease to include: (1) injury, oro-facial defects, malocclusion and temporomandibular joint dysfunction; (2) oral mucosal lesions; (3) systemic diseases with oral manifestations and (4) hazards associated with dental practice. Dentistry is now being practised with an ordered set of priorities.

  13. Single-Tooth Modeling for 3D Dental Model

    PubMed Central

    Yuan, Tianran; Liao, Wenhe; Dai, Ning; Cheng, Xiaosheng; Yu, Qing

    2010-01-01

    An integrated single-tooth modeling scheme is proposed for the 3D dental model acquired by optical digitizers. The cores of the modeling scheme are fusion regions extraction, single tooth shape restoration, and single tooth separation. According to the “valley” shape-like characters of the fusion regions between two adjoining teeth, the regions of the 3D dental model are analyzed and classified based on the minimum curvatures of the surface. The single tooth shape is restored according to the bioinformation along the hole boundary, which is generated after the fusion region being removed. By using the extracted boundary from the blending regions between the teeth and soft tissues as reference, the teeth can be separated from the 3D dental model one by one correctly. Experimental results show that the proposed method can achieve satisfying modeling results with high-degree approximation of the real tooth and meet the requirements of clinical oral medicine. PMID:20689718

  14. Quartz crystal microbalance and photoacoustic measurements in dental photocuring

    NASA Astrophysics Data System (ADS)

    Lima, Marcenilda A.; Bastos, Ivan N.; Cella, Norberto

    2016-09-01

    Photocured dental resins are used extensively in restorative procedures in dentistry. Inadequate curing reduces the lifetime of the dental restoration, and consequently it is essential to precisely measure the polymerisation kinetics. In this study, two techniques, Quartz Crystal Microbalance (QCM) and Photoacoustic Spectroscopy (PAS), were used to monitor the real-time cure and to obtain the optical absorption spectra of resins, respectively. From the PAS measurements, the precise peaks of absorption were identified, and were used as the appropriate wavelength of the photocuring light in the QCM monitoring. The combined use of these techniques allows reliable determination of the duration of the phases of physical and chemical changes that occur during photocuring. Two commercial dental resins were tested, and the results confirmed the advantages of using PAS and QCM to study polymerisation kinetics.

  15. Radiation-induced dental caries, prevention and treatment - A systematic review

    PubMed Central

    Gupta, Nishtha; Pal, Manoj; Rawat, Sheh; Grewal, Mandeep S.; Garg, Himani; Chauhan, Deepika; Ahlawat, Parveen; Tandon, Sarthak; Khurana, Ruparna; Pahuja, Anjali K.; Mayank, Mayur; Devnani, Bharti

    2015-01-01

    Treatment of head and neck cancers (HNCs) involves radiotherapy. Patients undergoing radiotherapy for HNCs are prone to dental complications. Radiotherapy to the head and neck region causes xerostomia and salivary gland dysfunction which dramatically increases the risk of dental caries and its sequelae. Radiation therapy (RT) also affects the dental hard tissues increasing their susceptibility to demineralization following RT. Postradiation caries is a rapidly progressing and highly destructive type of dental caries. Radiation-related caries and other dental hard tissue changes can appear within the first 3 months following RT. Hence, every effort should be focused on prevention to manage patients with severe caries. This can be accomplished through good preoperative dental treatment, frequent dental evaluation and treatment after RT (with the exception of extractions), and consistent home care that includes self-applied fluoride. Restorative management of radiation caries can be challenging. The restorative dentist must consider the altered dental substrate and a hostile oral environment when selecting restorative materials. Radiation-induced changes in enamel and dentine may compromise bonding of adhesive materials. Consequently, glass ionomer cements have proved to be a better alternative to composite resins in irradiated patients. Counseling of patients before and after radiotherapy can be done to make them aware of the complications of radiotherapy and thus can help in preventing them. PMID:27390489

  16. Evaluation of margin angles of collarless metal ceramic restorations.

    PubMed

    Dalvit, Deborah L; Parker, M Harry; Cameron, Stephen M; Hawkins, M Chad; Agar, John R; Brousseau, J Stephen

    2004-01-01

    This study was designed to measure the porcelain margin angles of completed collarless metal ceramic restorations and determine if these angles correspond to the most frequently recommended porcelain margin angle of 90 degrees. A sample of 99 metal ceramic restorations with porcelain labial margins were evaluated. A 1.0 mm slice taken from the midfacial impression of each restoration was evaluated by tooth location with a stereomaster microscope and the angle of the labial porcelain margin was calculated. The comparison of margin angles by tooth location showed no statistical difference between the groups. Comparison of the average margin angle with the most suggested 90-degree angle was analyzed with a One-Sample t-test and found to be statistically significant (p = 0.000). Although the majority of dental schools teach the shoulder preparation for collarless metal ceramic restorations, only 43% of the restorations measured fell within 10 degrees of this standard.

  17. Management of a patient suffering with Cherubism with dental implants.

    PubMed

    Dewan, Karun; Bishop, Karl

    2011-06-01

    Cherubism is a rare non-neoplastic, fibro-osseous hereditary disorder characterized by bilateral expansion of the maxilla and mandible producing a characteristic facial appearance. It can affect the facial and dental growth of the individual and often results in gross aesthetic and functional deficiencies. The teeth may also be displaced or submerged and these problems can often compromise successful restorative rehabilitation. This paper describes the restorative management of an adult patient with Cherubism involving a fixed implant retained mandibular restoration. The care utilized 3D planning software and implant insertion guides to facilitate an early loading protocol and the use of optimum bone quality/volume areas.

  18. Attitudes of Ohio dentists and dental hygienists on the use of automated external defibrillators.

    PubMed

    Kandray, Diane P; Pieren, Jennifer A; Benner, Randall W

    2007-04-01

    The American Heart Association reports that approximately 220,000 people die each year of sudden cardiac arrest. In ventricular fibrillation (VF), the most common abnormal heart rhythm that causes cardiac arrest, the heart's electrical impulses suddenly become chaotic, often without warning. Death will follow within minutes if the victim is not treated appropriately, and the only known treatment is defibrillation. An automated external defibrillator (AED) can restore a victim's normal heart rhythm by providing defibrillation. The purpose of this study was to gather data from dentists and dental hygienists in Ohio on their use of and attitudes toward using AEDs in dental offices. Six percent of Ohio dentists and dental hygienists were randomly selected to receive a twenty-three question survey related to their use of and attitudes toward their use of AEDs in dental offices. Thirty-three percent (244) of the surveys were returned; 41 percent of the respondents were dentists, and 59 percent were dental hygienists. Six percent said they have had to administer nitroglycerin to a patient during a dental visit; 5 percent have performed CPR on a patient in the dental office; and 78 percent said their last CPR training course included training on an AED. Eleven percent said there was an AED at their dental office. With the increased likelihood of dealing with a cardiac emergency in the dental office setting and the willingness of dental professionals to use an AED, all dental offices should consider obtaining an AED. Dental educators should become familiar with current protocols for handling cardiac medical emergencies in the dental office and prepare dental and dental hygiene students with the skills necessary to manage patients with cardiac emergencies. Graduating dental students entering private practice may want to consider the AED as part of their medical emergency office protocol.

  19. Functionalized bio-artifact fabricated via selective slurry extrusion. Part 2: Fabrication of ceramic dental crown.

    PubMed

    Zhu, D B; Liang, J P; Qu, Y X; Duan, G L

    2014-05-01

    Functionalized ceramic dental crown was successfully fabricated through selective slurry extrusion (SSE) based technique of solid freeform fabrication (also known as rapid prototyping). After sintering, the decomposed tourmaline powders were embedded in ZrO2 matrix. The far infrared emission properties of the ceramic dental crown were improved due to the increase of the numbers of infrared active bonds from tourmaline. This new dental restoration process presents potential to provide dental patients with functionalized artificial teeth, which benefits the body health by the way of emitting far infrared rays in ambient temperatures.

  20. Is it the end of the road for dental amalgam? A critical review

    PubMed Central

    Shenoy, Arvind

    2008-01-01

    The longevity of dental restorations is dependent on many factors, including those related to materials, the dentist, and the patient. Dental amalgams have successfully served the profession for over a century. The main reasons for restoration failure are secondary caries, fracture of the bulk of the restoration or of the tooth, and marginal deficiencies and wear. The importance of direct-placement, aesthetic, tooth-colored restorative materials is still increasing. Amalgam restorations are being replaced because of alleged adverse health effects and inferior aesthetic appearance. All alternative restorative materials and procedures, however, have certain limitations. This article will attempt to critically analyse both amalgams and resin based composites, through an evaluation of scientific literature. PMID:20142895

  1. What is dental ecology?

    PubMed

    Cuozzo, Frank P; Sauther, Michelle L

    2012-06-01

    Teeth have long been used as indicators of primate ecology. Early work focused on the links between dental morphology, diet, and behavior, with more recent years emphasizing dental wear, microstructure, development, and biogeochemistry, to understand primate ecology. Our study of Lemur catta at the Beza Mahafaly Special Reserve, Madagascar, has revealed an unusual pattern of severe tooth wear and frequent tooth loss, primarily the result of consuming a fallback food for which these primates are not dentally adapted. Interpreting these data was only possible by combining our areas of expertise (dental anatomy [FC] and primate ecology [MS]). By integrating theoretical, methodological, and applied aspects of both areas of research, we adopted the term "dental ecology"-defined as the broad study of how teeth respond to the environment. Specifically, we view dental ecology as an interpretive framework using teeth as a vehicle for understanding an organism's ecology, which builds upon earlier work, but creates a new synthesis of anatomy and ecology that is only possible with detailed knowledge of living primates. This framework includes (1) identifying patterns of dental pathology and tooth use-wear, within the context of feeding ecology, behavior, habitat variation, and anthropogenic change, (2) assessing ways in which dental development and biogeochemical signals can reflect habitat, environmental change and/or stress, and (3) how dental microstructure and macro-morphology are adapted to, and reflect feeding ecology. Here we define dental ecology, provide a short summary of the development of this perspective, and place our new work into this context.

  2. Adult heavy and low users of dental services: treatment provided.

    PubMed

    Nihtilä, Annamari; Widström, Eeva; Elonheimo, Outi

    2016-01-01

    The aim of this study was to compare treatment provided to adult heavy and low users of dental services in the Finnish Public Dental Service (PDS) and to analyse changes in patients' oral health status. We assigned all adults who attended the PDS in Espoo in 2004 to a group of heavy users (n = 3,173) if they had made six or more dental visits and to a comparison group of low users (n = 22,820), if they had made three or fewer dental visits. Data were obtained from the patient register of the PDS. A sample of 320 patients was randomly selected from each group. Baseline information (year 2004) on age, sex, number and types of visits, oral health status and treatment provided was collected from treatment records. Both groups were followed-up for five years. Restorative treatment measures dominated the heavy and low users'treatments; 88.8% of heavy users and 79.6% low users had received restorations during the five-year period. Fixed prosthetic treatments were provided to just 2% of the heavy users and 0.8% of the low users. Emergency visits were more common for heavy users (74.8%) than for low users (21.6%) (p < 0.001). Fewer than half of the heavy (46.1%) or low (46.5%) users were examined twice. Typical for heavy use of oral health services was a cycle of repetitive repair or replacement of restorations, often as emergency treatment, a lack of proper examinations and preventive care; crown therapy was seldom used. Immediately after the major dental care reform in Finland, the PDS in Espoo had problems providing good quality dental care for the new adult patients. Older patients with lower social class background were not accustomed to regular dental care and the PDS did not actively propose proper comprehensive regular care for adults.

  3. Dental hygiene in Slovakia.

    PubMed

    Luciak-Donsberger, C; Krizanová, M

    2004-08-01

    This article reports on the development of the dental hygiene profession in Slovakia from a global perspective. The aim is to inform about current developments and to examine, how access to qualified dental hygiene care might be improved and how professional challenges might be met. For an international study on dental hygiene, secondary source data were obtained from members of the House of Delegates of the International Federation of Dental Hygienists (IFDH) or by fax and e-mail from experts involved in the national professional and educational organization of dental hygiene in non-IFDH member countries, such as Slovakia. Responses were followed-up by interviews, e-mail correspondence, visits to international universities, and a review of supporting studies and reference literature. Results show that the introduction of dental hygiene in Slovakia in 1992 was inspired by the delivery of preventive care in Switzerland. Initiating local dentists and dental hygienists strive to attain a high educational level, equitable to that of countries in which dental hygiene has an established tradition of high quality care. Low access to qualified dental hygiene care may be a result of insufficient funding for preventive services, social and cultural lack of awareness of the benefits of preventive care, and of limitations inherent in the legal constraints preventing unsupervised dental hygiene practice. These may be a result of gender politics affecting a female-dominated profession and of a perception that dental hygiene is auxiliary to dental care. International comparison show that of all Eastern European countries, the dental hygiene profession appears most advanced in Slovakia. This is expressed in high evidence-based academic goals, in extensive work with international consultants from the Netherlands and Switzerland, in annual congresses of high professional quality, and in the establishment of a profession, which has not been introduced in all Western EU countries.

  4. Simplifying fixed implant dental prosthetics.

    PubMed

    Tischler, Michael

    2011-01-01

    Through following the FPPD protocol for multiple adjacent implants, and delivering final abutments, picking up the metal framework, and delivering provisionals, many benefits are gained. The benefits of following the FPPD protocol are as follows: The restorative dentist is trying-in and delivering the final abutments in one visit as opposed to removing them and placing them multiple times. This requires less chair time and time for the patient. It also reduces the mechanical stress on the abutment screw and implant body due to the elimination of multiple try-in appointments. When the metal framework is tried-in and verified for fit, the restorative dentist has the opportunity check the retention, check the margins, and make any corrections that might be needed. The abutments will be staying in the mouth when the framework is picked up. This metal try-in allows for a verification of the bite to be given to the dental lab. The delivery of provisionals manufactured by the dental laboratory offers many advantages in the FPPD technique. The patient has a form of tooth much earlier in the traditional appointment sequence. The patient can now offer feedback to the doctor and laboratory for fabrication of the permanent prosthesis with regards to shape and color. The laboratory-fabricated provisionals offer progressive loading to the implants through having a reduced occlusion yet allowing food to stimulate the implants. Overall, the FPPD technique offers shorter appointment times, more rapid delivery of fixed supported teeth, improved doctor-technician communication, and less mechanical wear on the implant parts.

  5. Histo-anatomic 3D printing of dental structures.

    PubMed

    Schweiger, J; Beuer, F; Stimmelmayr, M; Edelhoff, D; Magne, P; Güth, J F

    2016-11-04

    The creation of dental restorations with natural appearance and biomechanics represents a major challenge for the restorative team. The manufacturing-process of high-aesthetic restorations from tooth-coloured restorative materials is currently dominated by manual manufacturing procedures and the outcome is highly dependent on the knowledge and skills of the performing dental technician. On the other hand, due to the simplicity of the manufacturing process, CAD/CAM restorations from different material classes gain more and more acceptance in the daily routine. Multi-layered restorations show significant aesthetic advantages versus monolithic ones, but are difficult to fabricate using digital technologies. The key element for the successful automated digital fabrication of aesthetic anterior restorations seems to be the form of the individual dentine core as defined by dentine enamel junction (DEJ) covered by a more transparent layer of material imitating the enamel layer to create the outer enamel surface (OES). This article describes the possibilities and technologies available for so-called '4D-printing'. It introduces the digital manufacturing process of multilayered anterior teeth using 3D multipart printing, taking the example of manufacturing replicas of extracted intact natural teeth.

  6. Employment of Dental Hygienists as Dental Educators.

    ERIC Educational Resources Information Center

    Fong, Cynthia; Odrich, Johanna

    1987-01-01

    A study of the use of dental hygienists to teach periodontics, preventive dentistry, community dentistry, and public health courses looked at employment patterns and practices and the qualifications of the teachers. (MSE)

  7. Chlorhexidine-releasing methacrylate dental composite materials.

    PubMed

    Leung, Danny; Spratt, David A; Pratten, Jonathan; Gulabivala, Kishor; Mordan, Nicola J; Young, Anne M

    2005-12-01

    Light curable antibacterial, dental composite restoration materials, consisting of 80 wt% of a strontium fluoroaluminosilicate glass dispersed in methacrylate monomers have been produced. The monomers contained 40-100 wt% of a 10 wt% chlorhexidine diacetate (CHXA) in hydroxyethylmethacrylate (HEMA) solution and 60-0 wt% of a 50/50 mix of urethane dimethacrylate (UDMA) and triethyleneglycol dimethacrylate (TEGDMA). On raising HEMA content, light cure polymerisation rates decreased. Conversely, water sorption induced swelling and rates of diffusion controlled CHXA release from the set materials increased. Experimental composites with 50 and 90 wt% of the CHXA in HEMA solution in the monomer were shown, within a constant depth film fermentor (CDFF), to have slower rates of biofilm growth on their surfaces between 1 and 7 days than the commercial dental composite Z250 or fluoride-releasing dental cements, Fuji II LC and Fuji IX. When an excavated bovine dentine cylinder re-filled with Z250 was placed for 10 weeks in the CDFF, both bacteria and polymers from the artificial saliva penetrated between the material and dentine. With the 50 wt% experimental HEMA/CHXA formulation, this bacterial microleakage was substantially reduced. Polymer leakage, however, still occurred. Both polymer and bacterial microleakage were prevented with a 90 wt% HEMA/CHXA restoration in the bovine dentine due to swelling compensation for polymerisation shrinkage in combination with antibacterial release.

  8. Noncarious dental "abfraction" lesions in an aging population.

    PubMed

    Owens, B M; Gallien, G S

    1995-06-01

    A new classification for noncarious dental lesions has evolved from the dental literature. The name given to these lesions, dental "abfractions," is a theory propounding tooth fatigue, flexure, and deformation through biomechanical loading of tooth structure, primarily at the cervical regions of the dentition. These lesions are typically wedge shaped with sharp line angles, but occlusal abfractions have been observed as circular invaginations. Dental abfractions can occur alone and are sometimes associated with toothbrush abrasion and erosion from endogenous or exogenous acids. Treatment consists of the application of composite resin or glass-ionomer cement restorations and/or the discontinuance of the etiology of these lesions. If esthetics are not a primary concern of the patient and the tooth is not structurally compromised, many of these lesions can be observed, provided that the patient is informed that bruxism or malocclusion problems exist.

  9. [Cooperation between the dentist and the dental technician].

    PubMed

    Postema, N; van Overveld, H A

    2000-11-01

    In prosthetic dentistry the final result is mainly determined by the co-operation within the team: the dentist, the implantologist, the dental technician and the patient. The technician is more and more involved in the composition and colouring of the dental restorations. In many laboratories a dental unit is available to maximise the co-operation and to involve the patient if necessary. A plea is made to develop protocols to improve the co-operation between dentist and dental technician. At the same time new communication techniques can be used such as digital photography. As the costs are often high a treatment plan and an estimate of expenditure are necessary. It is advised that the dentist asks the technician to submit an offer. The dentist should realise that patients, because of the high costs, often have great expectations of the final result, which not always can be fulfilled.

  10. Advanced restorative dentistry - a problem for the elderly? An ethical dilemma.

    PubMed

    Murray, C G

    2015-03-01

    The type of dental restorations taken into old age may have an adverse effect on the quality of life of the elderly. Root caries and dry mouth increase in prevalence with age and may precipitate the breakdown of remaining natural and restored teeth. At present the availability of dental personnel and facilities in residential aged care facilities (RACFs) is limited, often non-existent, and the elderly living at home may be unable to easily gain access to dental care. Thus, the provision of appropriate and timely dental treatment may not occur, resulting in prolonged pain and suffering. It is important that, as our elderly population increasingly retain natural teeth into advanced old age, appropriate funds are made available to ensure their dental health is maintained. A lack of early intervention to arrest dental disease may result in life-threatening medical consequences in the elderly, such as ventilator assisted pneumonia or the need for a general anaesthetic and possible associated medical risks. Significant local disease, such as osteonecrosis, may also result from a lack of appropriate dental intervention. The necessity to remove questionable teeth prior to irradiation for neoplastic disease or bisphosphonate prescription for neoplastic disease or severe osteoporosis emphasizes the need for regular dental care. In contrast, extensive dental restorative treatment for younger people may have benefits, such as optimal dental aesthetics and oral function, but in older individuals careful consideration should be given to select the most appropriate treatment modality so that adverse situations can be avoided or their resolution simplified should they occur later when the individual is compromised or in a RACF. This may mean the use of conservative dental restorative materials and an avoidance of complex restorative options which may be difficult for the individual or RACF staff to maintain. Some years after receipt of their complex restorations they may be unable

  11. Breuner Marsh Restoration Project

    EPA Pesticide Factsheets

    Information about the San Francisco Bay Water Quality Project (SFBWQP) Breuner Marsh Restoration Project, part of an EPA competitive grant program to improve SF Bay water quality focused on restoring impaired waters and enhancing aquatic resources.

  12. Quartermaster Reach Restoration Project

    EPA Pesticide Factsheets

    Information about the SFBWQP Quartermaster Reach Restoration Project, part of an EPA competitive grant program to improve SF Bay water quality focused on restoring impaired waters and enhancing aquatic resources.

  13. Patterns of dental therapists' scope of practice and employment in Victoria, Australia.

    PubMed

    Satur, Julie; Gussy, Mark; Mariño, Rodrigo; Martini, Tamsin

    2009-03-01

    In Australia, dental therapists have practiced only within the state-operated School Dental Services (SDS) for around forty years providing preventive, diagnostic, restorative, and health promotion services to children and adolescents in a collaborative and referral relationship with dentists. Changes to legislation in 2000 have seen limits to dental therapists' employment removed, allowing private sector employment. This study examines the changes to dental therapists' employment since 2000 using a self-completed questionnaire with a response rate of 82 percent. Approximately one-third of responding dental therapists reported that they spent some time employed outside the SDS in community health services and private orthodontic and general practices, which indicates an acceptance of this type of dental care provider in these areas. The clinical services that dental therapists are currently providing are a complex mix with significant variations according to type and geographical location of practice, but include high levels of patient assessment, diagnosis, treatment planning, and the restoration of teeth. The findings from this study indicate that when legislative restrictions on employment settings are removed, there is a demand and demonstrable role for dental therapist-delivered services in nongovernment dental practices.

  14. Clinical survey on type of restoration in deciduous teeth.

    PubMed

    Fukuyama, Tatsuro; Oda, Shinya; Yamashita, Haruto; Sekiguchi, Hiroshi; Yakushiji, Masashi

    2008-02-01

    This study was conducted in 533 children with 1,634 treated teeth who visited the Pediatric Dentistry Department at the Chiba Hospital of Tokyo Dental College between January and December, 2003. Restorations on deciduous tooth were categorized by age of patient and tooth type. The following observations were made: Children aged 4 (17.9%) visited the clinic most frequently and this group had the highest number of deciduous restorations (21.3%). Among the 1,634 deciduous teeth restored, metal inlays were provided in 29.4% of total teeth restored, composite resin restorations in 27.2%, stainless-steel crowns in 25.7%, composite resin full crowns in 7.7%, glass-ionomer cement restorations in 6.6%, and amalgam restorations in 3.4%. By age, composite resin was most frequently used in children aged 1 to 3. In children aged 5 to 9, metal inlay was most frequently used. Those aged 4 received mostly stainless-steel crowns. Composite resin restorations were used mostly in anterior deciduous teeth, and metal inlays mostly in deciduous molars. Previous research indicated an increasing trend towards composite resin restorations and composite resin full crowns. The present study also confirmed such a trend. While the use of metal inlays and stainless-steel crowns tended to increase until 1987, the present study indicated a trend to decrease.

  15. Pathways in dental public health.

    PubMed

    Silverstein, Steven J

    2005-07-01

    Dental public health is one of the nine specialties of dentistry recognized by the American Dental Association Commission on Dental Accreditation. Dental public health has been defined as the "science and art of preventing and controlling dental diseases and promoting dental health through organized community efforts. It is that form of dental practice which serves the community as a patient rather than as an individual. It is concerned with the dental health education of the public, with applied dental research, and with the administration of group dental care programs as well as the prevention and control of dental diseases on a community basis." This article will describe the many career and educational pathways dentists may follow to become irvolved in the practice of dental public health.

  16. Restorative dentistry for children.

    PubMed

    Donly, Kevin J

    2013-01-01

    This article discusses contemporary pediatric restorative dentistry. Indications and contraindications for the choice of different restorative materials in different clinical situations, including the risk assessment of the patient, are presented. The specific use of glass ionomer cement or resin-modified glass ionomer cement, resin-based composite, and stainless steel crowns is discussed so that preparation design and restoration placement is understood.

  17. The Post-Amalgam Era: Norwegian Dentists' Experiences with Composite Resins and Repair of Defective Amalgam Restorations.

    PubMed

    Kopperud, Simen E; Staxrud, Frode; Espelid, Ivar; Tveit, Anne Bjørg

    2016-04-22

    Amalgam was banned as a dental restorative material in Norway in 2008 due to environmental considerations. An electronic questionnaire was sent to all dentists in the member register of the Norwegian Dental Association (NTF) one year later, to evaluate dentists' satisfaction with alternative restorative materials and to explore dentists' treatment choices of fractured amalgam restorations. Replies were obtained from 61.3%. Composite was the preferred restorative material among 99.1% of the dentists. Secondary caries was the most commonly reported cause of failure (72.7%), followed by restoration fractures (25.1%). Longevity of Class II restorations was estimated to be ≥10 years by 45.8% of the dentists, but 71.2% expected even better longevity if the restoration was made with amalgam. Repair using composite was suggested by 24.9% of the dentists in an amalgam restoration with a fractured cusp. Repair was more often proposed among young dentists (p < 0.01), employees in the Public Dental Service (PDS) (p < 0.01) and dentists working in counties with low dentist density (p = 0.03). There was a tendency towards choosing minimally invasive treatment among dentists who also avoided operative treatment of early approximal lesions (p < 0.01). Norwegian dentists showed positive attitudes towards composite as a restorative material. Most dentists chose minimally- or medium invasive approaches when restoring fractured amalgam restorations.

  18. The Post-Amalgam Era: Norwegian Dentists’ Experiences with Composite Resins and Repair of Defective Amalgam Restorations

    PubMed Central

    Kopperud, Simen E.; Staxrud, Frode; Espelid, Ivar; Tveit, Anne Bjørg

    2016-01-01

    Amalgam was banned as a dental restorative material in Norway in 2008 due to environmental considerations. An electronic questionnaire was sent to all dentists in the member register of the Norwegian Dental Association (NTF) one year later, to evaluate dentists’ satisfaction with alternative restorative materials and to explore dentists’ treatment choices of fractured amalgam restorations. Replies were obtained from 61.3%. Composite was the preferred restorative material among 99.1% of the dentists. Secondary caries was the most commonly reported cause of failure (72.7%), followed by restoration fractures (25.1%). Longevity of Class II restorations was estimated to be ≥10 years by 45.8% of the dentists, but 71.2% expected even better longevity if the restoration was made with amalgam. Repair using composite was suggested by 24.9% of the dentists in an amalgam restoration with a fractured cusp. Repair was more often proposed among young dentists (p < 0.01), employees in the Public Dental Service (PDS) (p < 0.01) and dentists working in counties with low dentist density (p = 0.03). There was a tendency towards choosing minimally invasive treatment among dentists who also avoided operative treatment of early approximal lesions (p < 0.01). Norwegian dentists showed positive attitudes towards composite as a restorative material. Most dentists chose minimally- or medium invasive approaches when restoring fractured amalgam restorations. PMID:27110804

  19. Copper release from dental prosthetic crowns, dental materials, and human teeth into acetic acid.

    PubMed

    Kalicanin, Biljana M; Nikolić, Ruzica S

    2010-01-01

    This article examines the dilution of the ion of copper from human teeth and dental prosthetic crowns in 4% CH(3)COOH during a period of 24 hr at room temperature. The content of the diluted copper in an acetate extract, as well as the overall content of this metal in the samples, was determined by means of a potentiometric stripping analysis. The comparative measurements were carried out using the furnace atomic absorption spectrophotometry technique, which is recommended by the International Standards (ISO 6872:2008; ISO 24234:2004) as a method for quality control of dental-prosthetic material (dental ceramic, metal restorative materials, dental amalgams) in the process of checking for heavy metals. During a 24-hr period in 4% CH(3)COOH at a temperature of 25 degrees C, approximately 72% of the overall copper was released from the tooth. The percentage of the released copper from baby teeth is higher, ranging from 88 to 92%, which is probably a consequence of the bone tissue being in development, its infirmity, and inadequate stability. On these conditions, approximately 72% of the overall copper was released from the dental-ceramic prosthetic crowns.

  20. International dental standards.

    PubMed

    Jones, Derek W

    2007-09-22

    International dental standards are vital in maintaining the safety and quality of both the products and materials used by dental professionals and the many oral health products used by members of the general public, yet many dentists will be unaware of the role standards play in their daily practice. In this article, Derek W. Jones outlines the vital work of the International Standards Organization and highlights how standards pervade nearly every dental procedure.