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Sample records for hard tooth tissue

  1. Melatonin Effects on Hard Tissues: Bone and Tooth

    PubMed Central

    Liu, Jie; Huang, Fang; He, Hong-Wen

    2013-01-01

    Melatonin is an endogenous hormone rhythmically produced in the pineal gland under the control of the suprachiasmatic nucleus (SCN) and the light/dark cycle. This indole plays an important role in many physiological processes including circadian entrainment, blood pressure regulation, seasonal reproduction, ovarian physiology, immune function, etc. Recently, the investigation and applications of melatonin in the hard tissues bone and tooth have received great attention. Melatonin has been investigated relative to bone remolding, osteoporosis, osseointegration of dental implants and dentine formation. In the present review, we discuss the large body of published evidence and review data of melatonin effects on hard tissues, specifically, bone and tooth. PMID:23665905

  2. Microprocessing of human hard tooth tissues surface by mid-infrared erbium lasers radiation

    NASA Astrophysics Data System (ADS)

    Belikov, Andrey V.; Shatilova, Ksenia V.; Skrypnik, Alexei V.

    2015-03-01

    A new method of hard tooth tissues laser treatment is described. The method consists in formation of regular microdefects on tissue surface by mid-infrared erbium laser radiation with propagation ratio M2<2 (Er-laser microprocessing). Proposed method was used for preparation of hard tooth tissues surface before filling for improvement of bond strength between tissues surface and restorative materials, microleakage reduction between tissues surface and restorative materials, and for caries prevention as a result of increasing microhardness and acid resistance of tooth enamel.

  3. In vitro thermal diffusivity measurements as aging process study in human tooth hard tissues

    NASA Astrophysics Data System (ADS)

    Carvalho, A. P. N.; Dias, D. T.; Bedeschi, V. C.; Nakamura, O.; Oliveira, M. Q.

    2013-11-01

    In the present work, the Open Photoacoustic Cell Technique was used to find effective thermal diffusivity of human tooth hard tissues, a thermal variable of great interest in the biological science, and inorganic materials. The aging process of the tooth enamel and dentin was analyzed through its effective thermal diffusivity. The study in vitro of these samples showed an increase and posterior decrease with aging of the samples. The values found for the enamel and dentin samples, varied from (36-55)×10-4 cm2 s-1 and (20-32)×10-4 cm2 s-1, respectively.

  4. [Age and gender changes of apatites from human hard tooth tissues].

    PubMed

    Pikhur, O L; Ryzhak, G A; Iordanishvili, A K; Iankovskiĭ, V V; D'iakonov, M M

    2014-01-01

    Apatites of hard tissues of teeth of persons of different sex and age were studied in detail. It is shown that the crystal structure of apatites depends on changes in the composition of the enamel that happen during a person's life. Limits of the variations of the crystal lattice parameters of the enamel apatites connected with the complicate processes of de- and remineralization have been determined. On the basis of the identified correlations between chemical composition, crystal lattice parameters and age of patients, the complicated interrelated isomorphic replacements occurring in the crystal structure of apatites of hard tooth tissues during aging were analysed. PMID:25946859

  5. Comparison of hard tissue interrelationships at the cervical region of teeth based on tooth type and gender difference

    PubMed Central

    Astekar, Madhusudan; Kaur, Prabhpreet; Dhakar, Nidhi; Singh, Jappreet

    2014-01-01

    Context: Cementoenamel junction (CEJ) represents the anatomic limit between the crown and root surface. With advancing age and continuous eruption, this area becomes exposed in the oral media. Consequently, CEJ will be subjected to the action of various physical and chemical factors that might alter its morphology, with the cementum being affected in most cases. Aim: To identify the frequency of hard tissue interrelationships present at the CEJ in relation to different genders, positions and aspects of tooth using a light microscope. Materials and Methods: The cervical regions of 80 permanent teeth (40 male and 40 female), extracted for orthodontic or periodontal reasons, were analyzed after longitudinal ground sections were made in the mesio-distal plane. The CEJ of the prepared sections was then studied and their frequencies were categorized as: cementum overlapping enamel, enamel overlapping cementum, edge-to-edge relationship and the presence of gap junctions. Statistical Analysis: Chi-square test performed using SPSS 15 software. Results: Edge-to-edge contact of the cementum and enamel was most frequent, followed by gap junction and cementum overlapping the enamel, respectively. Chi-square test revealed no statistically significant differences with respect to the gender and tooth aspect, whereas the result was significant when the position of the tooth was studied. Conclusion: The observations of the study indicate a considerable morphological diversity in the anatomical pattern of CEJ. It can be concluded that the region should be protected against dentinal sensitivity, erosion, abrasion, abfraction and resorption, as it is more prone to cervical pathologies. PMID:25125914

  6. Hard tissue laser procedures.

    PubMed

    Gimbel, C B

    2000-10-01

    A more conservative, less invasive treatment of the carious lesion has intrigued researchers and clinicians for decades. With over 170 million restorations placed worldwide each year, many of which could be treated using a laser, there exists an increasing need for understanding hard tissue laser procedures. An historical review of past scientific and clinical hard research, biophysics, and histology are discussed. A complete review of present applications and procedures along with their capabilities and limitations will give the clinician a better understanding. Clinical case studies, along with guidelines for tooth preparation and hard tissue laser applications and technological advances for diagnosis and treatment will give the clinician a look into the future. PMID:11048281

  7. Tissue Interactions Regulating Tooth Development and Renewal.

    PubMed

    Balic, Anamaria; Thesleff, Irma

    2015-01-01

    Reciprocal interactions between epithelial and mesenchymal tissues play a fundamental role in the morphogenesis of teeth and regulate all aspects of tooth development. Extensive studies on mouse tooth development over the past 25 years have uncovered the molecular details of the signaling networks mediating these interactions (reviewed by Jussila & Thesleff, 2012; Lan, Jia, & Jiang, 2014). Five conserved signaling pathways, namely, the Wnt, BMP, FGF, Shh, and Eda, are involved in the mediation of the successive reciprocal epithelial-mesenchymal cross talk which follows the general principle of morphogenetic interactions (Davidson, 1993). The pathways regulate the expression of transcription factors which confer the identity of dental epithelium and mesenchyme. The signals and transcription factors are integrated in complex signaling networks whose fine-tuning allows the generation of the variation in tooth morphologies. In this review, we describe the principles and molecular mechanisms of the epithelial-mesenchymal interactions regulating successive stages of tooth formation: (i) the initiation of tooth development, with special reference to the shift of tooth-forming potential from epithelium to mesenchyme; (ii) the morphogenesis of the tooth crown, focusing on the roles of epithelial signaling centers; (iii) the differentiation of odontoblasts and ameloblasts, which produce dentin and enamel, respectively; and (iv) the maintenance of dental stem cells, which support the continuous growth of teeth. PMID:26589925

  8. Surface modulation of dental hard tissues

    NASA Astrophysics Data System (ADS)

    Tantbirojn, Daranee

    Tooth surfaces play a central role in the equilibrium of dental hard tissues, in which contrasting processes lead to loss or deposition of materials. The central interest of this Thesis was the modulation of tooth surfaces to control such equilibrium. Four specific studies were carried out to investigate different classes of surface modulating agents. These are: (1) Ionic modulation of the enamel surface to enhance stain removal . Dental stain is the most apparent form of tooth surface deposit. The nature of extrinsic stain in terms of spatial chemical composition was studied by using electron probe microanalysis. An ionic surface modulating agent, sodium tripolyphosphate (STPP), was evaluated. Image analysis methodologies were developed and the ability of STPP in stain removal was proved. (2) Thin film modulation with substantive polymeric coating and the effect on in vitro enamel de/re-mineralization . A novel polymeric coating that formed a thin film on the tooth surface was investigated for its inhibitory effect on artificial enamel caries, without interfering with the remineralization process. The preventive effect was distinct, but the mineral redeposition was questionable. (3) Thick film modulation with fluoride containing sealants and the effect on in vitro enamel and root caries development. Fluoride incorporated into resin material is an example of combining different classes of surface modulating agents to achieve an optimal outcome. A proper combination, such as in resin modified glass ionomer, showed in vitro caries inhibitory effect beyond the material boundary in both enamel and dentin. (4) Thick film modulation with dental adhesives and the determination of adhesion to dentin. Dentin adhesives modulate intracoronal tooth surfaces by enhancing adhesion to restorative materials. Conventional nominal bond tests were inadequate to determine the performance of current high strength adhesives. It was shown that interfacial fracture toughness test was more

  9. CO2 laser milling of hard tissue

    NASA Astrophysics Data System (ADS)

    Werner, Martin; Ivanenko, Mikhail; Harbecke, Daniela; Klasing, Manfred; Steigerwald, Hendrik; Hering, Peter

    2007-02-01

    Drilling of bone and tooth tissue belongs to recurrent medical procedures (screw- and pin-bores, bores for implant inserting, trepanation etc.). Small round bores can be in general quickly produced with mechanical drills. Problems arise however by angled drilling, by the necessity to fulfill the drilling without damaging of sensitive soft tissue beneath the bone, or by the attempt to mill precisely noncircular small cavities. We present investigations on laser hard tissue "milling", which can be advantageous for solving these problems. The "milling" is done with a CO2 laser (10.6 μm) with pulse duration of 50 - 100 μs, combined with a PC-controlled galvanic beam scanner and with a fine water-spray, which helps to avoid thermal side-effects. The damaging of underlying soft tissue can be prevented through control of the optical or acoustical ablation signal. The ablation of hard tissue is accompanied with a strong glowing, which is absent during the laser beam action on soft tissue. The acoustic signals from the diverse tissue types exhibit distinct differences in the spectral composition. Also computer image analysis could be a useful tool to control the operation. Laser "milling" of noncircular cavities with 1 - 4 mm width and about 10 mm depth is particularly interesting for dental implantology. In ex-vivo investigations we found conditions for fast laser "milling" of the cavities without thermal damage and with minimal tapering. It included exploration of different filling patterns (concentric rings, crosshatch, parallel lines and their combinations), definition of maximal pulse duration, repetition rate and laser power, optimal position of the spray. The optimized results give evidences for the applicability of the CO2 laser for biologically tolerable "milling" of deep cavities in the hard tissue.

  10. FATIGUE OF BIOMATERIALS: HARD TISSUES

    PubMed Central

    Arola, D.; Bajaj, D.; Ivancik, J.; Majd, H.; Zhang, D.

    2009-01-01

    The fatigue and fracture behavior of hard tissues are topics of considerable interest today. This special group of organic materials comprises the highly mineralized and load-bearing tissues of the human body, and includes bone, cementum, dentin and enamel. An understanding of their fatigue behavior and the influence of loading conditions and physiological factors (e.g. aging and disease) on the mechanisms of degradation are essential for achieving lifelong health. But there is much more to this topic than the immediate medical issues. There are many challenges to characterizing the fatigue behavior of hard tissues, much of which is attributed to size constraints and the complexity of their microstructure. The relative importance of the constituents on the type and distribution of defects, rate of coalescence, and their contributions to the initiation and growth of cracks, are formidable topics that have not reached maturity. Hard tissues also provide a medium for learning and a source of inspiration in the design of new microstructures for engineering materials. This article briefly reviews fatigue of hard tissues with shared emphasis on current understanding, the challenges and the unanswered questions. PMID:20563239

  11. Biomaterials in Tooth Tissue Engineering: A Review

    PubMed Central

    Sharma, Sarang; Srivastava, Dhirendra; Grover, Shibani; Sharma, Vivek

    2014-01-01

    Biomaterials play a crucial role in the field of tissue engineering. They are utilized for fabricating frameworks known as scaffolds, matrices or constructs which are interconnected porous structures that establish a cellular microenvironment required for optimal tissue regeneration. Several natural and synthetic biomaterials have been utilized for fabrication of tissue engineering scaffolds. Amongst different biomaterials, polymers are the most extensively experimented and employed materials. They can be tailored to provide good interconnected porosity, large surface area, adequate mechanical strengths, varying surface characterization and different geometries required for tissue regeneration. A single type of material may however not meet all the requirements. Selection of two or more biomaterials, optimization of their physical, chemical and mechanical properties and advanced fabrication techniques are required to obtain scaffold designs intended for their final application. Current focus is aimed at designing biomaterials such that they will replicate the local extra cellular environment of the native organ and enable cell-cell and cell-scaffold interactions at micro level required for functional tissue regeneration. This article provides an insight into the different biomaterials available and the emerging use of nano engineering principles for the construction of bioactive scaffolds in tooth regeneration. PMID:24596804

  12. Express diagnostics of intact and pathological dental hard tissues by optical PNC method

    NASA Astrophysics Data System (ADS)

    Masychev, Victor I.; Alexandrov, Michail T.

    2000-03-01

    The results of hard tooth tissues research by the optical PNC- method in experimental and clinical conditions are presented. In the experiment under 90 test-sample of tooth slices with thickness about 1 mm (enamel, dentine and cement) were researched. The results of the experiment were processed by the method of correlation analyze. Clinical researches were executed on teeth of 210 patients. The regions of tooth tissue diseases with initial, moderate and deep caries were investigated. Spectral characteristics of intact and pathologically changed tooth tissues are presented and their peculiar features are discussed. The results the optical PNC- method application while processing tooth carious cavities are presented in order to estimate efficiency of the mechanical and antiseptic processing of teeth. It is revealed that the PNC-method can be used as for differential diagnostics of a degree dental carious stage, as for estimating of carefulness of tooth cavity processing before filling.

  13. Laser Ablatin of Dental Hard Tissue

    SciTech Connect

    Seka, W.; Rechmann, P.; Featherstone, J.D.B.; Fried, D.

    2007-07-31

    This paper discusses ablation of dental hard tissue using pulsed lasers. It focuses particularly on the relevant tissue and laser parameters and some of the basic ablation processes that are likely to occur. The importance of interstitial water and its phase transitions is discussed in some detail along with the ablation processes that may or may not directly involve water. The interplay between tissue parameters and laser parameters in the outcome of the removal of dental hard tissue is discussed in detail.

  14. Quantitative analysis of incipient mineral loss in hard tissues

    NASA Astrophysics Data System (ADS)

    Matvienko, Anna; Mandelis, Andreas; Hellen, Adam; Jeon, Raymond; Abrams, Stephen; Amaechi, Bennett

    2009-02-01

    A coupled diffuse-photon-density-wave and thermal-wave theoretical model was developed to describe the biothermophotonic phenomena in multi-layered hard tissue structures. Photothermal Radiometry was applied as a safe, non-destructive, and highly sensitive tool for the detection of early tooth enamel demineralization to test the theory. Extracted human tooth was treated sequentially with an artificial demineralization gel to simulate controlled mineral loss in the enamel. The experimental setup included a semiconductor laser (659 nm, 120 mW) as the source of the photothermal signal. Modulated laser light generated infrared blackbody radiation from teeth upon absorption and nonradiative energy conversion. The infrared flux emitted by the treated region of the tooth surface and sub-surface was monitored with an infrared detector, both before and after treatment. Frequency scans with a laser beam size of 3 mm were performed in order to guarantee one-dimensionality of the photothermal field. TMR images showed clear differences between sound and demineralized enamel, however this technique is destructive. Dental radiographs did not indicate any changes. The photothermal signal showed clear change even after 1 min of gel treatment. As a result of the fittings, thermal and optical properties of sound and demineralized enamel were obtained, which allowed for quantitative differentiation of healthy and non-healthy regions. In conclusion, the developed model was shown to be a promising tool for non-invasive quantitative analysis of early demineralization of hard tissues.

  15. Restorative dentistry for children using a hard tissue laser.

    PubMed

    Jacobson, Barry; Asgari, Ali

    2008-09-01

    This article will describe how a hard tissue laser is used in various restorative procedures. The erbium family of lasers (Er,Cr:YSGG and Er:YAG) are highly absorbed in water and, to a lesser extent, in tooth mineral. Because a carious lesion contains significantly more water than healthy enamel or dentin, the laser can offer some selectivity in removing the diseased material. Furthermore, these lasers can offer some degree of anesthesia. In these clinical photos, an Er,Cr:YSGG laser (Waterlase or Waterlase MD, 2780-nm; Biolase Technologies, Irvine, CA) was used. PMID:19127930

  16. CO II laser free-form processing of hard tissue

    NASA Astrophysics Data System (ADS)

    Werner, Martin; Klasing, Manfred; Ivanenko, Mikhail; Harbecke, Daniela; Steigerwald, Hendrik; Hering, Peter

    2007-07-01

    Drilling and surface processing of bone and tooth tissue belongs to standard medical procedures (bores and embeddings for implants, trepanation etc.). Small circular bores can be generally quickly produced with mechanical drills. However problems arise at angled drilling, the need to execute drilling procedures without damaging of sensitive soft tissue structures underneath the bone or the attempt to mill small non-circular cavities in hard tissue with high precision. We present investigations on laser hard tissue "milling", which can be advantageous for solving these problems. The processing of bone is done with a CO II laser (10.6 μm) with pulse durations of 50 - 100 μs, combined with a PC-controlled fast galvanic laser beam scanner and a fine water-spray, which helps keeping the ablation process effective and without thermal side-effects. Laser "milling" of non-circular cavities with 1 - 4 mm width and about 10 mm depth can be especially interesting for dental implantology. In ex-vivo investigations we found conditions for fast laser processing of these cavities without thermal damage and with minimised tapering. It included the exploration of different filling patterns (concentric rings, crosshatch, parallel lines, etc.), definition of maximal pulse duration, repetition rate and laser power, and optimal water spray position. The optimised results give evidence for the applicability of pulsed CO II lasers for biologically tolerable effective processing of deep cavities in hard tissue.

  17. [Biomechanical study on orthodontic tooth movement: changes in biomechanical property of the periodontal tissue in terms of tooth mobility].

    PubMed

    Inoue, Y

    1989-12-01

    The magnitude of tooth mobility has been frequently used for evaluating biomechanical response of the periodontal tissue to applied forces. However, tooth mobility during orthodontic tooth movement has not been measured. The purpose of this study was to investigate changes in biomechanical property of the periodontal tissue during canine retraction, in terms of tooth mobility. The upper canines on both sides of ten orthodontic patients were moved in the distal direction for about four weeks with an initial force of 200 gf. An amount of tooth movement and a magnitude of tooth mobility were measured every 3 or 4 days during retraction. A distally directed force up to 500 gf was continuously applied to each canine and tooth mobility was measured with a noncontact type of eddy current displacement sensor. A two-dimensional finite element model was constructed and displacements of the finite element model were calculated with various Young's moduli in loading with a 100 gf force in the distal direction. In comparison with the magnitudes of the tooth mobility, Young's modulus of the periodontal membrane before retraction and the influence of the biomechanical factors on changes in tooth mobility were investigated. The tooth movement curve was divided into three phases; an initial phase, a lag phase and a post-lag phase. The magnitudes of tooth mobility at the initial phase were significantly larger than those before retraction within the range of 250 gf to 500 gf and these magnitudes decreased during the lag phase. The magnitudes of tooth mobility at the post-lag phase significantly increased, within the range of 50 gf to 500 gf, than those before retraction. As a result of curveliniar regression analysis, the tooth mobility curves approximated to delta = AFB, where delta and F denote tooth mobility and force respectively. The coefficients A and B changed according to the phases of tooth movement. An inclination of the tooth mobility curve expressed by a tangent at the

  18. The SCPP gene family and the complexity of hard tissues in vertebrates.

    PubMed

    Kawasaki, Kazuhiko

    2011-01-01

    Diverse hard tissues constituted a tooth-like skeletal element in extinct jawless vertebrates. Today, similar tissues are found in our teeth. These tissues mineralize in the extracellular matrix and involve various macromolecules. Among these molecules are secretory calcium-binding phosphoproteins (SCPPs) coded by genes that arose by duplication. Although the repertoire of SCPPs may vary in different lineages, some SCPPs are unusually acidic and are thought to participate in the mineralization of a collagenous matrix, principally either bone or dentin. Other SCPPs are rich in Pro and Gln (P/Q) and are employed to form the tooth surface. In tetrapods, the tooth surface is usually covered with enamel which develops in a matrix comprised of P/Q-rich SCPPs. By contrast, the tooth surface tissue in teleosts is called enameloid and it forms in a dentin-like collagenous matrix. Despite the difference in their matrix, both enamel and enameloid mature into hypermineralized inorganic tissues. Notably, some P/Q-rich SCPP genes are primarily expressed at this stage and their proteins localize between the tooth surface and overlying dental epithelium. Moreover, an orthologous gene is used for maturation of these 2 different tissues. These findings suggest distinct roles of acidic and P/Q-rich SCPPs during the evolution of hard tissues. Acidic SCPPs initially regulated the mineralization of bone, dentin, or a similar ancient collagenous tissue through interaction with calcium ions. P/Q-rich SCPPs arose next and originally assembled a structure or a space that facilitated the hypermineralization of dentin or a dentin-like tissue. Subsequently, some P/Q-rich SCPPs were coopted for the mineralizing enamel matrix. More recently, however, many SCPP genes were lost in toothless birds and mammals. Thus, it appears that, in vertebrates, the phenotypic complexity of hard tissues correlates with gain and loss of SCPP genes. PMID:21576905

  19. PROTEIN TEMPLATES IN HARD TISSUE ENGINEERING

    PubMed Central

    George, Anne; Ravindran, Sriram

    2010-01-01

    Biomineralization processes such as formation of bones and teeth require controlled mineral deposition and self-assembly into hierarchical biocomposites with unique mechanical properties. Ideal biomaterials for regeneration and repair of hard tissues must be biocompatible, possess micro and macroporosity for vascular invasion, provide surface chemistry and texture that facilitate cell attachment, proliferation, differentiation of lineage specific progenitor cells, and induce deposition of calcium phosphate mineral. To expect in-vivo like cellular response several investigators have used extracellular matrix proteins as templates to recreate in-vivo microenvironment for regeneration of hard tissues. Recently, several novel methods of designing tissue repair and restoration materials using bioinspired strategies are currently being formulated. Nanoscale structured materials can be fabricated via the spontaneous organization of self-assembling proteins to construct hierarchically organized nanomaterials. The advantage of such a method is that polypeptides can be specifically designed as building blocks incorporated with molecular recognition features and spatially distributed bioactive ligands that would provide a physiological environment for cells in-vitro and in-vivo. This is a rapidly evolving area and provides a promising platform for future development of nanostructured templates for hard tissue engineering. In this review we try to highlight the importance of proteins as templates for regeneration and repair of hard tissues as well as the potential of peptide based nanomaterials for regenerative therapies. PMID:20802848

  20. Imaging of hard- and soft-tissue structure in the oral cavity by optical coherence tomography

    SciTech Connect

    Colston, Bill W.; Everett, Mathew J.; Da Silva, Luiz B. Otis, Linda L. Stroeve, Pieter Nathel, Howard

    1998-06-01

    We have developed a prototype optical coherent tomography (OCT) system for the imaging of hard and soft tissue in the oral cavity. High-resolution images of {ital in vitro} porcine periodontal tissues have been obtained with this system. The images clearly show the enamel{endash}cementum and the gingiva{endash}tooth interfaces, indicating OCT is a potentially useful technique for diagnosis of periodontal diseases. To our knowledge, this is the first application of OCT for imaging biologic hard tissue. {copyright} 1998 Optical Society of America

  1. Lasers and hard-tissue interactions

    NASA Astrophysics Data System (ADS)

    Makropoulou, Mersini I.; Papagiakoumou, Eirini I.

    2004-06-01

    The hard tissue laser ablation and the relevant laser applications on dental tissues have attracted several investigators, since the ablation efficiency, the lateral thermal and/or mechanical damage and the final surface characteristics must be optimised, in order to fulfil the efficient and safe removal of pathological dental areas in a clinical environment. For example, it was theoretically predicted that the lateral tissue thermal damage might be limited when the laser intensity is high and the interaction time is short. In this case the Q-switched Er:YAG laser operating with a pulse length below the thermal relaxation time of the irradiated tissue, is considered to be very effective. Therefore, the efficacy of the Q-switched Er:YAG laser, versus the free-running operation mode, on dentine ablation was studied, as well as the morphological changes at the irradiated dentine surface. Additionally, the interaction of nanosecond UV laser pulses and IR/visible picosecond laser pulses with hard tissue samples was investigated for comparative evaluation of the different laser ablation mechanisms.

  2. Dental hard tissue characterization using laser-based ultrasonics

    NASA Astrophysics Data System (ADS)

    Blodgett, David W.; Massey, Ward L.

    2003-07-01

    Dental health care and research workers require a means of imaging the structures within teeth in vivo. One critical need is the detection of tooth decay in its early stages. If decay can be detected early enough, the process can be monitored and interventional procedures, such as fluoride washes and controlled diet, can be initiated to help re-mineralize the tooth. Currently employed x-ray imaging is limited in its ability to visualize interfaces and incapable of detecting decay at a stage early enough to avoid invasive cavity preparation followed by a restoration. To this end, non-destructive and non-contact in vitro measurements on extracted human molars using laser-based ultrasonics are presented. Broadband ultrasonic waves are excited in the extracted sections by using a pulsed carbon-dioxide (CO2) laser operating in a region of high optical absorption in the dental hard tissues. Optical interferometric detection of the ultrasonic wave surface displacements in accomplished with a path-stabilized Michelson-type interferometer. Results for bulk and surface in-vitro characterization of caries are presented on extracted molars with pre-existing caries.

  3. Autotransplantation of a tooth using guided tissue regeneration.

    PubMed

    Hürzeler, M B; Quiñones, C R

    1993-08-01

    Autotransplantation is an alternative treatment to replace missing or periodontally-involved hopeless teeth. A prerequisite for performing this procedure is having a recipient site with sufficient bone volume to support the transplant. Often, however, crestal bone resorption following tooth extraction or periodontitis results in a reduced alveolar ridge with inadequate dimensions to properly house the transplant. In these cases, the procedure is contraindicated. A case is presented in which the biologic principle of guided tissue regeneration was used to gain periodontal support around an autotransplanted 3rd molar. The results suggest the potential use of guided tissue regeneration in conjunction with autotransplantation. This may represent a new area in reconstructive dentistry. PMID:8354731

  4. Comparison of soft and hard tissue ablation with sub-ps and ns pulse lasers

    SciTech Connect

    Da Silva, L.B.; Stuart, B.C.; Celliers, P.M.; Feit, M.D.; Glinsky, M.E.; Heredia, N.J.; Herman, S.; Lane, S.M.; London, R.A.; Matthews, D.L.; Perry, M.D.; Rubenchik, A.M.; Chang, T.D.; Neev, J.

    1996-05-01

    Tissue ablation with ultrashort laser pulses offers several unique advantages. The nonlinear energy deposition is insensitive to tissue type, allowing this tool to be used for soft and hard tissue ablation. The localized energy deposition lead to precise ablation depth and minimal collateral damage. This paper reports on efforts to study and demonstrate tissue ablation using an ultrashort pulse laser. Ablation efficiency and extent of collateral damage for 0.3 ps and 1000 ps duration laser pulses are compared. Temperature measurements of the rear surface of a tooth section is also presented.

  5. Hard tissue remodeling using biofabricated coralline biomaterials.

    PubMed

    Vago, Razi; Plotquin, Daniel; Bunin, Alex; Sinelnikov, Igor; Atar, Dan; Itzhak, David

    2002-01-01

    Biotechnical and biomedical approaches were combined in an attempt to identify potential uses of biofabricated marine carbonate materials in biomedical applications, particularly as biomatrices for remodeling bone and cartilage tissue. After grafting, it is desirable for bone ingrowth to proceed as quickly as possible because the strength of the implanted region depends on a good mechanical bond forming between the implant and surrounding regions in the body. Ingrowth can take place as a result of growth of tissue and cells into the implanted porous material, or it may be promoted by transplanting cells seeded onto such a material. The rate at which ingrowth occurs is dependent on many factors, including pore size and the interconnectivity of the implanted structure. In vivo graftings into osteochondral defects demonstrated that our biofabricated porous material is highly biocompatible with cartilage and bone tissue. The biofabricated matrix was well incorporated into the biphasic osteochondral area. Resorption was followed by bone and cartilage formation, and after 4 months, the biomaterial had been replaced by new tissue. Ossification was induced and enhanced without introduction of additional factors. We believe that this is the first time that such biofabricated materials have been used for biomedical purposes. In face of the obvious environmental disadvantages of harvesting from limited natural resources, we propose the use of bioengineered coralline and other materials such as those cultured by our group under field and laboratory conditions as a possible biomatrix for hard tissue remodeling. PMID:11741712

  6. Measurements of erbium laser-ablation efficiency in hard dental tissues under different water cooling conditions.

    PubMed

    Kuščer, Lovro; Diaci, Janez

    2013-10-01

    Laser triangulation measurements of Er:YAG and Er,Cr:YSGG laser-ablated volumes in hard dental tissues are made, in order to verify the possible existence of a "hydrokinetic" effect that has been proposed as an alternative to the "subsurface water expansion" mechanism for hard-tissue laser ablation. No evidence of the hydrokinetic effect could be observed under a broad range of tested laser parameters and water cooling conditions. On the contrary, the application of water spray during laser exposure of hard dental material is observed to diminish the laser-ablation efficiency (AE) in comparison with laser exposure under the absence of water spray. Our findings are in agreement with the generally accepted principle of action for erbium laser ablation, which is based on fast subsurface expansion of laser-heated water trapped within the interstitial structure of hard dental tissues. Our measurements also show that the well-known phenomenon of ablation stalling, during a series of consecutive laser pulses, can primarily be attributed to the blocking of laser light by the loosely bound and recondensed desiccated minerals that collect on the tooth surface during and following laser ablation. In addition to the prevention of tooth bulk temperature buildup, a positive function of the water spray that is typically used with erbium dental lasers is to rehydrate these minerals, and thus sustaining the subsurface expansion ablation process. A negative side effect of using a continuous water spray is that the AE gets reduced due to the laser light being partially absorbed in the water-spray particles above the tooth and in the collected water pool on the tooth surface. Finally, no evidence of the influence of the water absorption shift on the hypothesized increase in the AE of the Er,Cr:YSGG wavelength is observed. PMID:24105399

  7. Coordination of tooth morphogenesis and neuronal development through tissue interactions: lessons from mouse models.

    PubMed

    Luukko, Keijo; Kettunen, Päivi

    2014-07-15

    In addition to being an advantageous model to investigate general molecular mechanisms of organ formation, the tooth is a distinct target organ for peripheral nerve innervation. These nerves are required for the function and protection of the teeth and, as shown in fish, also for their regeneration. This review focuses on recent findings of the local tissue interactions and molecular signaling mechanisms that regulate the early nerve arrival and patterning of mouse mandibular molar tooth sensory innervation. Dental sensory nerve growth and patterning is a stepwise process that is intimately linked to advancing tooth morphogenesis. In particular, nerve growth factor and semaphorin 3A serve as essential functions during and are iteratively used at different stages of tooth innervation. The tooth germ controls development of its own nerve supply, and similar to the development of the tooth organ proper, tissue interactions between dental epithelial and mesenchymal tissues control the establishment of tooth innervation. Tgf-β, Wnt, and Fgf signaling, which regulate tooth formation, are implicated to mediate these interactions. Therefore, tissue interactions mediated by conserved signal families may constitute key mechanism for the integration of tooth organogenesis and development of its peripheral nerve supply. PMID:24631295

  8. Comparison of tetrachromic VOF stain to other histochemical staining techniques for characterizing stromal soft and hard tissue components.

    PubMed

    Belaldavar, C; Hallikerimath, S; Angadi, P V; Kale, A D

    2014-11-01

    The components of hard tissues including dentin, enamel, cementum, bone and other calcified deposits, and mature and immature collagen pose problems for identification in routine hematoxylin and eosin (H & E) stained sections. Use of combinations of stains can demonstrate the components of hard tissues and soft tissues distinctly. We assessed the efficacy of the Verde Luz-orange G-acid fuchsin (VOF) stain for differentiating hard and soft connective tissues and compared results with other histochemical staining techniques. Eighty tissue sections comprising developing tooth (30), ossifying fibroma (30) and miscellaneous pathologies (20) expected to contain varying types of calcified tissues were stained with H & E, VOF, and Masson's trichrome (MT). In developing tooth, VOF demonstrated better differentiation of hard tissues, while it was comparable to MT for ossifying fibroma and miscellaneous pathologies. The intensity of staining was greater with VOF than with the other stains studied. VOF stains hard tissue components distinctly and gives good contrast with the surrounding connective tissue. VOF is comparable to MT, but has added advantages including single step staining, rapid and easy procedures, and it distinguishes the maturity of the tissues. PMID:24830362

  9. Tooth Disorders

    MedlinePlus

    ... made of a hard, bonelike material. Inside the tooth are nerves and blood vessels. You need your ... These include eating, speaking and even smiling. But tooth disorders are nothing to smile about. They include ...

  10. Microstructure of dental hard tissues in fossil and recent xenarthrans (Mammalia: Folivora and Cingulata).

    PubMed

    Kalthoff, Daniela C

    2011-06-01

    A striking difference between xenarthrans and other mammals is the complete loss of tooth enamel in all members but the earliest armadillos. However, sloth and armadillo teeth show structured wear facets, which in all other mammals are formed by tooth enamel. How is that possible? Here, I report about an analysis of fossil and recent xenarthran dental hard tissue microstructure. It shows that osteodentine is not exclusive to fossil Cingulata, but also occurs in some recent taxa. Furthermore, I found profound modifications of orthodentine architecture in comparison to other mammals. Remarkable features are (a) a larger proportion of the highly mineralized, collagen-free peritubular dentine, and (b) a modified architecture of the odontoblastic process with frequent interconnections between the extensions and unusually intensive branching of the extensions forming a complex meshwork, penetrating the intertubular dentine matrix. The orthodentine microstructural build-up is unique in Folivora and Cingulata. PMID:21456028

  11. In vivo OCT imaging of hard and soft tissue of the oral cavity

    NASA Astrophysics Data System (ADS)

    Feldchtein, Felix I.; Gelikonov, V. M.; Iksanov, R. R.; Gelikonov, G. V.; Kuranov, R. V.; Sergeev, Alexander M.; Gladkova, N.; Ourutina, M. N.; Reitze, David H.; Warren, J. A.

    1998-09-01

    We use optical coherence tomography (OCT) to perform a comprehensive program of in vivo and in vitro structural imaging of hard and soft tissues within the oral cavity. We have imaged the different types of healthy oral mucosa as well as normal and abnormal tooth structure. OCT is able to differentiate between the various types of keratinized and non-keratinized mucosa with high resolution. OCT is also able to provide detailed structural information on clinical abnormalities (caries and non-caries lesions) in teeth and provide guidance in dental restorative procedures. Our investigations demonstrate the utility of OCT as a diagnostic imaging modality in clinical and research dentistry.

  12. Improved methods for immunohistochemical detection of BrdU in hard tissue.

    PubMed

    Shimada, Akemi; Shibata, Tatsuya; Komatsu, Koichiro; Nifuji, Akira

    2008-11-30

    Bromodeoxyuridine (BrdU) is used to label synthesizing DNA and to chase label-retaining cell (LRC). As stem cells divide slowly in adult tissues, they can be visualized as LRCs. In order to identify LRCs in hard tissue, we examined optimal conditions of fixation, demineralization, and DNA denaturation/antigen retrieval for immunohistochemistry of BrdU in hard tissues including bone, tooth, and periodontal ligament. Mice were subcutaneously injected with BrdU (50 microg/g body weight) twice a day from the postnatal day 11 to day 15 and sacrificed at 2 h after the last injection. Dissected maxillae were fixed (Bouin's solution or 4% paraformaldehyde), demineralized (Morse's solution or EDTA), and embedded in paraffin. Antigen retrieval procedures were performed before incubation with primary antibody. When sections were treated with HCl for DNA denaturation, the staining intensity of BrdU positive cells was not affected by difference of fixatives. Higher sensitivity was obtained by demineralization with Morse than with EDTA. Although heat-induced antigen retrieval techniques in citrate buffer (pH 6.0) showed as well or better sensitivity than acid pretreatment, heating caused tissue damage specifically to tooth dentine and the surrounding tissue. When the LRCs at four weeks after the last injection of BrdU were compared, much more LRCs were observed in specimen demineralized with Morse than with 10% EDTA. Our data suggest that demineralization with Morse with Bouin fixative plus HCl pretreatment gives rise to the optimal results for BrdU immunodetection in hard tissue. PMID:18718840

  13. Current considerations concerning endodontically treated teeth: alteration of hard dental tissues and biomechanical properties following endodontic therapy.

    PubMed

    Dimitriu, Bogdan; Vârlan, Constantin; Suciu, Ioana; Vârlan, Virginia; Bodnar, Dana

    2009-01-01

    The aim of this general article is to present an overview of the current knowledge about composition and structural changes and also about specific biomechanical alterations related to vitality loss or endodontic therapy. For a long time, these issues have been controversially approached from a clinical standpoint and are therefore still confusing for many practitioners. Vitality loss or endodontic procedures seem to induce only negligible changes in hard dental tissue moisture. Physico-chemical properties of dentin can be modified by some of the endodontic chemical products used for chemo-mechanical debridement. On the other hand, tooth biomechanical behavior is affected, since tooth strength is reduced proportionally to coronal tissue loss, due to either pre-existent carious/non-carious lesions or cavity acces preparation, besides restorative procedures. The related literature shows the lack of accepted clinical standards and consensus regarding the optimal way of approaching the specific tooth biomechanics following endodontic therapy. PMID:20108492

  14. Laser processing of dental hard tissues (Invited Paper)

    NASA Astrophysics Data System (ADS)

    Fried, Daniel

    2005-04-01

    In addition to their use for the painless removal of dental decay, lasers are also well suited to modify the chemical composition of the mineral phase of dental hard tissues in order to render the tissues more resistant to acid dissolution and for the modification of the hard tissue morphology for better adhesion to restorative materials. In this paper the principal applications of lasers for the processing of dental hard tissues are discussed with an emphasis on the influence of an externally applied layer of water. The presence of an optically thick layer of water profoundly influences the phase composition of the laser irradiated tissue surface and the morphology resulting in more efficient ablation, better adhesion and improved resistance to acid dissolution.

  15. Dental histology of Coelophysis bauri and the evolution of tooth attachment tissues in early dinosaurs.

    PubMed

    Fong, Raymond K M; LeBlanc, Aaron R H; Berman, David S; Reisz, Robert R

    2016-07-01

    Studies of dinosaur teeth have focused primarily on external crown morphology and thus, use shed or in situ tooth crowns, and are limited to the enamel and dentine dental tissues. As a result, the full suites of periodontal tissues that attach teeth to the jaws remain poorly documented, particularly in early dinosaurs. These tissues are an integral part of the tooth and thus essential to a more complete understanding of dental anatomy, development, and evolution in dinosaurs. To identify the tooth attachment tissues in early dinosaurs, histological thin sections were prepared from the maxilla and dentary of a partial skull of the early theropod Coelophysis bauri from the Upper Triassic (Rhaetian- 209-201 Ma) Whitaker Quarry, New Mexico, USA. As one of the phylogenetically and geologically oldest dinosaurs, it is an ideal candidate for examining dental tissues near the base of the dinosaurian clade. The teeth of C. bauri exhibited a fibrous tooth attachment in which the teeth possessed five tissues: enamel, dentine, cementum, periodontal ligament (PDL), and alveolar bone. Our findings, coupled with those of more recent studies of ornithischian teeth, indicate that a tripartite periodontium, similar to that of crocodilians and mammals, is the plesiomorphic condition for dinosaurs. The occurrence of a tripartite periodontium in dinosaurs adds to the growing consensus that the presence of these tissues is the plesiomorphic condition for the major amniote clades. Furthermore, this study establishes the relative timing of tissue development and growth directions of periodontal tissues and provides the first comparative framework for future studies of dinosaur periodontal development, tooth replacement, and histology. J. Morphol. 277:916-924, 2016. © 2016 Wiley Periodicals, Inc. PMID:27087142

  16. Probing microscopic mechanical properties of hard tissues with Brillouin spectroscopy

    NASA Astrophysics Data System (ADS)

    Meng, Zhaokai; Yakovlev, Vladislav V.

    2015-02-01

    Mechanical properties of hard tissues play an important role in understanding underlying biological structures, as well as assessing the quality of artificial bone replacement materials. In this study, we employed Brillouin spectroscopy as a non-invasive approach to probe the microscopic elasticity of hard tissues, such as bones. Brillouin spectra were collected using a background free virtually imaged phased array spectrometer. As a reference, Raman spectra were also acquired for each imaging point. Experimental results reveal a positive correlation between the local concentration of the mineral content and the corresponding tissue stiffness, assessed through a Brillouin shift.

  17. X-ray microscopy of soft and hard human tissues

    NASA Astrophysics Data System (ADS)

    Müller, Bert; Schulz, Georg; Deyhle, Hans; Stalder, Anja K.; Ilgenstein, Bernd; Holme, Margaret N.; Weitkamp, Timm; Beckmann, Felix; Hieber, Simone E.

    2016-01-01

    The simultaneous post mortem visualization of soft and hard tissues using absorption-based CT remains a challenge. If the photon energy is optimized for the visualization of hard tissue, the surrounding soft tissue components are almost X-ray transparent. Therefore, the combination with other modalities such as phase-contrast CT, magnetic resonance microscopy, and histology is essential to detect the anatomical features. The combination of the 2D and 3D data sets using sophisticated segmentation and registration tools allows for conclusions about otherwise inaccessible anatomical features essential for improved patient treatments.

  18. Tooth histology in the cretaceous ichthyosaur Platypterygius australis, and its significance for the conservation and divergence of mineralized tooth tissues in amniotes.

    PubMed

    Maxwell, Erin E; Caldwell, Michael W; Lamoureux, Denis O

    2011-02-01

    Ichthyosaurs are an extinct group of secondarily aquatic reptiles that show ligamentous tooth attachment to the jaw in some derived forms. Here, we provide a modern description of tooth histology in ichthyosaurs, using Platypterygius australis, a large ichthyosaur from the Cretaceous of Australia. Our study supports evolutionary conservation of the principal mineralized tooth tissue types in amniotes with ligamentous tooth attachment: enamel, dentine, cellular, and acellular cementum. This is the first time that the latter tissue has been located in ichthyosaurs. Vascularized cementum (osteocementum) is reduced or absent in amniotes in which the teeth are ankylosed to the jaw bone, such as basal ichthyosaurs, and raises questions regarding the function of this tissue and the potential developmental or selective conditions leading to its convergent evolution. PMID:21210486

  19. Tooth abscess

    MedlinePlus

    ... swelling within the tooth. This causes a painful toothache . The toothache may stop if the pulp of the tooth ... tissue. Symptoms The main symptom is a severe toothache. The pain is continuous. It can be described ...

  20. Porous Biodegradable Metals for Hard Tissue Scaffolds: A Review

    PubMed Central

    Yusop, A. H.; Bakir, A. A.; Shaharom, N. A.; Abdul Kadir, M. R.; Hermawan, H.

    2012-01-01

    Scaffolds have been utilized in tissue regeneration to facilitate the formation and maturation of new tissues or organs where a balance between temporary mechanical support and mass transport (degradation and cell growth) is ideally achieved. Polymers have been widely chosen as tissue scaffolding material having a good combination of biodegradability, biocompatibility, and porous structure. Metals that can degrade in physiological environment, namely, biodegradable metals, are proposed as potential materials for hard tissue scaffolding where biodegradable polymers are often considered as having poor mechanical properties. Biodegradable metal scaffolds have showed interesting mechanical property that was close to that of human bone with tailored degradation behaviour. The current promising fabrication technique for making scaffolds, such as computation-aided solid free-form method, can be easily applied to metals. With further optimization in topologically ordered porosity design exploiting material property and fabrication technique, porous biodegradable metals could be the potential materials for making hard tissue scaffolds. PMID:22919393

  1. Soft and hard tissue management using lasers in esthetic restoration.

    PubMed

    Flax, Hugh D

    2011-04-01

    Laser technology has become preeminent in the evolution of appearance enhancements. Dentistry has seen a huge breakthrough with the introduction of a combination hard-soft tissue erbium wavelength. The conservative nature of this technique has created a firm footing in the antiaging trend that is spanning the globe. Among the many benefits of this technique are less invasive care and quicker healing responses. In this article, conservative laser and cosmetic modalities are discussed that allows a clinician to be more comfortable in buying a soft/hard tissue laser and also to more quickly become adept with implementing these techniques. PMID:21474000

  2. Sectioning and imaging hard mineral fibres in biological tissues.

    PubMed

    Johnson, N F; Ibe, K

    1981-04-01

    A technique is described which overcomes the problems associated with sectioning biological tissue containing hard mineral fibres. 0.2--0.5 micrometer thick sections were cut with a diamond knife, placed in a folding grid, conventionally stained with uranyl acetate and lead citrate and viewed at an accelerating voltage of 200 kV in the scanning transmission mode. PMID:6163862

  3. [Hard dental tissue minimal-invasive preparation using contemporary polymer rotating instruments and laser].

    PubMed

    Beloica, Milos; Vulićević, Zoran R; Mandinić, Zoran; Radović, Ivana; Jovicić, Olivera; Carević, Momir; Tekić, Jasmina

    2014-01-01

    Goal of contemporary dentistry is to decrease the patient's discomfort during treatment. Dentists aim to achieve maximum with the newly developed dental materials as well as with new cavity preparation techniques in the shortest time span. Since the development of the first constructed borer (drilling machine) for caries removal, the preparation techniques have considerably changed. The progress of dental materials as well as the cavity preparation techniques has led us to contemporary carbide tungsten and diamond borers that are used with obligatory water cooling. The innovation within this field represents newly developed polymer borers that can detect the difference between carious lesions and healthy tooth structure. In this way the cavity preparation may be performed without damaging dental healthy tissue. This is possible owing to their hardness which is lower than the hardness of intact dentin. Polymer borer preparation is painless with less vibration, while the increase in temperature is negligible. Lasers have been used in clinical dentistry since 1980s so it can be said that they represent a new technology. The function of lasers is based on ablation which requires water. Erbium lasers have shown the highest potential with their ability to produce effective ablation of hard dental tissues. Laser application in dentistry requires special training as well as some protective measures. Laser advantages, compared to traditional preparation techniques, involve the absence of vibration, painless preparation, possibility of preparation without anesthetic and easier patient's adjustment to dental intervention which is of importance, especially in pediatric dentistry. PMID:25033597

  4. Low-intensity lasers, modern filling materials, and bonding systems influence on mineral metabolism of hard dental tissues

    NASA Astrophysics Data System (ADS)

    Kunin, Anatoly A.; Yesaulenko, I. E.; Zoibelmann, M.; Pankova, Svetlana N.; Ippolitov, Yu. A.; Oleinik, Olga I.; Popova, T. A.; Koretskaya, I. V.; Shumilovitch, Bogdan R.; Podolskaya, Elana E.

    2001-10-01

    One of the main reasons of low quality filling is breaking Ca-P balance in hard tissues. Our research was done with the purpose of studying the influence of low intensity lasers, diodic radiation, the newest filling and bonding systems on the processes of mineral metabolism in hard dental tissues while filling a tooth. 250 patients having caries and its compli-cations were examined and treated. Our complex research included: visual and instrumental examination, finding out the level of oral cavity hygiene, acid enamel biopsy, scanning electronic microscopy and X-ray spectrum microanalysis. Filling processes may produce a negative effect on mineral metabolism of hard dental tissues the latter is less pronounced when applying fluoride-containing filling materials with bonding systems. It has also been found that bonding dentin and enamel systems are designed for both a better filling adhesion (i.e. mechanical adhesion) and migration of useful microelements present in them by their sinking into hard dental tissues (i.e. chemical adhesion). Our research showed a positive influence of low intensity laser and diodic beams accompanying the use of modern filling and bonding systems on mineral metabolism of hard dental tissues.

  5. Photoacoustic imaging in both soft and hard biological tissue

    NASA Astrophysics Data System (ADS)

    Li, T.; Dewhurst, R. J.

    2010-03-01

    To date, most Photoacoustic (PA) imaging results have been from soft biotissues. In this study, a PA imaging system with a near-infrared pulsed laser source has been applied to obtain 2-D and 3-D images from both soft tissue and post-mortem dental samples. Imaging results showed that the PA technique has the potential to image human oral disease, such as early-stage teeth decay. For non-invasive photoacoustic imaging, the induced temperature and pressure rises within biotissues should not cause physical damage to the tissue. Several simulations based on the thermoelastic effect have been applied to predict initial temperature and pressure fields within a tooth sample. Predicted initial temperature and pressure rises are below corresponding safety limits.

  6. Data Fitting to Study Ablated Hard Dental Tissues by Nanosecond Laser Irradiation

    PubMed Central

    Abdel-Daiem, A. M.; Ansari, M. Shahnawaze; Babkair, Saeed S.; Salah, Numan A.; Al-Mujtaba, A.

    2016-01-01

    Laser ablation of dental hard tissues is one of the most important laser applications in dentistry. Many works have reported the interaction of laser radiations with tooth material to optimize laser parameters such as wavelength, energy density, etc. This work has focused on determining the relationship between energy density and ablation thresholds using pulsed, 5 nanosecond, neodymium-doped yttrium aluminum garnet; Nd:Y3Al5O12 (Nd:YAG) laser at 1064 nanometer. For enamel and dentin tissues, the ablations have been performed using laser-induced breakdown spectroscopy (LIBS) technique. The ablation thresholds and relationship between energy densities and peak areas of calcium lines, which appeared in LIBS, were determined using data fitting. Furthermore, the morphological changes were studied using Scanning Electron Microscope (SEM). Moreover, the chemical stability of the tooth material after ablation has been studied using Energy-Dispersive X-Ray Spectroscopy (EDX). The differences between carbon atomic % of non-irradiated and irradiated samples were tested using statistical t-test. Results revealed that the best fitting between energy densities and peak areas of calcium lines were exponential and linear for enamel and dentin, respectively. In addition, the ablation threshold of Nd:YAG lasers in enamel was higher than that of dentin. The morphology of the surrounded ablated region of enamel showed thermal damages. For enamel, the EDX quantitative analysis showed that the atomic % of carbon increased significantly when laser energy density increased. PMID:27228169

  7. Data Fitting to Study Ablated Hard Dental Tissues by Nanosecond Laser Irradiation.

    PubMed

    Al-Hadeethi, Y; Al-Jedani, S; Razvi, M A N; Saeed, A; Abdel-Daiem, A M; Ansari, M Shahnawaze; Babkair, Saeed S; Salah, Numan A; Al-Mujtaba, A

    2016-01-01

    Laser ablation of dental hard tissues is one of the most important laser applications in dentistry. Many works have reported the interaction of laser radiations with tooth material to optimize laser parameters such as wavelength, energy density, etc. This work has focused on determining the relationship between energy density and ablation thresholds using pulsed, 5 nanosecond, neodymium-doped yttrium aluminum garnet; Nd:Y3Al5O12 (Nd:YAG) laser at 1064 nanometer. For enamel and dentin tissues, the ablations have been performed using laser-induced breakdown spectroscopy (LIBS) technique. The ablation thresholds and relationship between energy densities and peak areas of calcium lines, which appeared in LIBS, were determined using data fitting. Furthermore, the morphological changes were studied using Scanning Electron Microscope (SEM). Moreover, the chemical stability of the tooth material after ablation has been studied using Energy-Dispersive X-Ray Spectroscopy (EDX). The differences between carbon atomic % of non-irradiated and irradiated samples were tested using statistical t-test. Results revealed that the best fitting between energy densities and peak areas of calcium lines were exponential and linear for enamel and dentin, respectively. In addition, the ablation threshold of Nd:YAG lasers in enamel was higher than that of dentin. The morphology of the surrounded ablated region of enamel showed thermal damages. For enamel, the EDX quantitative analysis showed that the atomic % of carbon increased significantly when laser energy density increased. PMID:27228169

  8. Improved Contact X-Ray Microradiographic Method to Measure Mineral Density of Hard Dental Tissues.

    PubMed

    Schmuck, B D; Carey, C M

    2010-03-01

    Contact X-ray microradiography is the current gold standard for measuring mineral densities of partially demineralized tooth specimens. The X-ray sensitive film specified in the last J Res NIST publication on the subject is no longer commercially available. OBJECTIVES: Develop a new microradiographic method by identifying a commercially available film with greater than 3000 lines per millimeter resolution, which is sensitive to X rays, and develop correct film processing for X-ray microradiographic application. METHODS: A holographic film was identified as a potential replacement film. Proper exposure was determined utilizing a thick nickel plate to create test-strips. Film development was bracketed around manufacturer suggestions. Film linearity was determined with aluminum step-wedges. Microradiographs of 100 µm thick tooth sections, before and after acidic challenges, were a final test for film. Magnified images were captured with a digital microscope camera with 0.305 micrometers per pixel resolution. RESULTS: The appropriate film exposure was 30 minutes at 80 kV(p) and 3 mA with a development time of 2 minutes. Step-wedge experiments show the system to be linear in terms of pixel intensities with respect to x-ray attenuation for normalized pixel intensity values that are 10% to 90% of full scale (r(2) = 0.997) which encompasses the full exposure region of tooth tissue. Enamel sections were analyzed and show distinctive differences between erosion and demineralization. The image capture device resolution of 0.305 micrometers per pixel limits the system resolution. CONCLUSION: Use of the identified holographic film when combined with the described processing modifications has resulted in an improved X-ray microradiographic method for the measurement of mineral density of dental hard tissues. The method described can be further improved by using a higher resolution digitization system. The method is appropriate for quantitatively measuring changes in mineral

  9. Early characterization of occlusal overloaded cervical dental hard tissues by en face optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Marcauteanu, Corina; Negrutiu, Meda; Sinescu, Cosmin; Stoica, Eniko Tunde; Ionita, Ciprian; Florin, Topala; Vasile, Liliana; Bradu, Adrian; Dobre, George; Podoleanu, Adrian G.

    2011-06-01

    Early diagnosis of occlusal overload is an important issue in dental medicine. The high occlusal forces can cause irreversible damage to the dental hard tissues. Our study proposes the early microstructural characterization of occlusal overloaded bicuspids, with abnormal crown morphology, by en face optical coherence tomography (eFOCT). The dental samples were investigated using an eFOCT system operating at 1300 nm in B-scan and C-scan mode. The eFOCT images obtained from these teeth visualized cracks, which didn't reach the tooth surface. The μCT and histological images confirmed the microstructural defects identified on eFOCT images. In conclusion, eFOCT is a promising imaging method for the early diagnosis of occlusal overload on bicuspids with normal crown morphology and for the prophylaxis of dental wear.

  10. Age-related changes of dental pulp tissue after experimental tooth movement in rats.

    PubMed

    Von Böhl, Martina; Ren, Yijin; Kuijpers-Jagtman, Anne M; Fudalej, Piotr S; Maltha, Jaap C

    2016-01-01

    It is generally accepted that the effect of orthodontic tooth movement on the dental pulp in adolescents is reversible and that it has no long-lasting effect on pulpal physiology. However, it is not clear yet if the same conclusion is also valid for adult subjects. Thus, in two groups of rats, aged 6 and 40 weeks respectively, 3 molars at one side of the maxilla were moved together in a mesial direction with a standardized orthodontic appliance delivering a force of 10 cN. The contralateral side served as a control. Parasagittal histological sections were prepared after tooth movement for 1, 2, 4, 8, and 12 weeks. The pulp tissue was characterized for the different groups, with special emphasis on cell density, inflammatory cells, vascularity, and odontoblasts. Dimensions of dentin and the pulpal horns was determined and related with the duration of orthodontic force application and age ware evaluated. We found that neither in young nor in adult rats, force application led to long-lasting or irreversible changes in pulpal tissues. Dimensional variables showed significant age-related changes. In conclusion, orthodontic tooth movement per se has no long-lasting or irreversible effect on pulpal tissues, neither in the young nor in the adult animals. PMID:26855867

  11. Age-related changes of dental pulp tissue after experimental tooth movement in rats

    PubMed Central

    Von Böhl, Martina; Ren, Yijin; Kuijpers-Jagtman, Anne M.; Maltha, Jaap C.

    2016-01-01

    It is generally accepted that the effect of orthodontic tooth movement on the dental pulp in adolescents is reversible and that it has no long-lasting effect on pulpal physiology. However, it is not clear yet if the same conclusion is also valid for adult subjects. Thus, in two groups of rats, aged 6 and 40 weeks respectively, 3 molars at one side of the maxilla were moved together in a mesial direction with a standardized orthodontic appliance delivering a force of 10 cN. The contralateral side served as a control. Parasagittal histological sections were prepared after tooth movement for 1, 2, 4, 8, and 12 weeks. The pulp tissue was characterized for the different groups, with special emphasis on cell density, inflammatory cells, vascularity, and odontoblasts. Dimensions of dentin and the pulpal horns was determined and related with the duration of orthodontic force application and age ware evaluated. We found that neither in young nor in adult rats, force application led to long-lasting or irreversible changes in pulpal tissues. Dimensional variables showed significant age-related changes. In conclusion, orthodontic tooth movement per se has no long-lasting or irreversible effect on pulpal tissues, neither in the young nor in the adult animals. PMID:26855867

  12. Application of Coenzyme Q10 for Accelerating Soft Tissue Wound Healing after Tooth Extraction in Rats

    PubMed Central

    Yoneda, Toshiki; Tomofuji, Takaaki; Kawabata, Yuya; Ekuni, Daisuke; Azuma, Tetsuji; Kataoka, Kota; Kunitomo, Muneyoshi; Morita, Manabu

    2014-01-01

    Accelerating wound healing after tooth extraction is beneficial in dental treatment. Application of antioxidants, such as reduced coenzyme Q10 (rCoQ10), may promote wound healing after tooth extraction. In this study, we examined the effects of topical application of rCoQ10 on wound healing after tooth extraction in rats. After maxillary first molars were extracted, male Fischer 344 rats (8 weeks old) (n = 27) received topical application of ointment containing 5% rCoQ10 (experimental group) or control ointment (control group) to the sockets for 3 or 8 days (n = 6–7/group). At 3 days after extraction, the experimental group showed higher collagen density and lower numbers of polymorphonuclear leukocytes in the upper part of socket, as compared to the control group (p < 0.05). Gene expression of interleukin-1β, tumor necrosis factor-α and nuclear factor-κB were also lower in the experimental group than in the control group (p < 0.05). At 8 days after tooth extraction, there were no significant differences in collagen density, number of polymorphonuclear leukocytes and bone fill between the groups. Our results suggest that topical application of rCoQ10 promotes wound healing in the soft tissue of the alveolar socket, but that rCoQ10 has a limited effect on bone remodeling in rats. PMID:25514392

  13. [The elemental composition of teeth hard tissues depending on the state of the environment].

    PubMed

    Suladze, N; Shishniashvili, T; Margvelashvili, V; Kobakhidze, K

    2014-01-01

    At present, great attention is paid to the origin of man-made micro elemental anomalies. To monitor the state of the environment and its effects on the human body, of great importance is the determination of the amount and distribution of various chemical elements in the dentin and enamel of the teeth. To determine the essential (Ca, Zn, Mn, Ni), conditionally essential (Rb, Ni, Sr) and toxic (Pb, Hg) trace elements in the mineralized tissues of the teeth and to identify the relationship between the elemental composition of the tooth structure and the state of the general and dental health depending on the state of the environment, we have examined 29 children aged 3-4 years who have carried out analysis of hard tissue of teeth (teeth used for remote medical reasons) for the maintenance of nine chemical elements. Children living in a relatively environmentally favorable conditions essential value and conditionally essential elements in the mineralized tissues of the teeth were within normal limits, and toxic elements slightly increased limits that differ from those of children living in environmentally disadvantaged areas. In particular, these essential elements were significantly reduced (except for zinc), as indicators of toxic elements - mercury and lead, increased by 12.5% and 44.5%, respectively, which is clearly reflected on the state of dental health because noted decompensated form of tooth decay. Thus, deviations in a state of general and dental health of children associated with an imbalance of macro-and microelements in the mineralized tissues of the teeth. PMID:24523324

  14. Laser-induced autofluorescence of oral cavity hard tissues

    NASA Astrophysics Data System (ADS)

    Borisova, E. G.; Uzunov, Tz. T.; Avramov, L. A.

    2007-03-01

    In current study oral cavity hard tissues autofluorescence was investigated to obtain more complete picture of their optical properties. As an excitation source nitrogen laser with parameters - 337,1 nm, 14 μJ, 10 Hz (ILGI-503, Russia) was used. In vitro spectra from enamel, dentine, cartilage, spongiosa and cortical part of the periodontal bones were registered using a fiber-optic microspectrometer (PC2000, "Ocean Optics" Inc., USA). Gingival fluorescence was also obtained for comparison of its spectral properties with that of hard oral tissues. Samples are characterized with significant differences of fluorescence properties one to another. It is clearly observed signal from different collagen types and collagen-cross links with maxima at 385, 430 and 480-490 nm. In dentine are observed only two maxima at 440 and 480 nm, related also to collagen structures. In samples of gingival and spongiosa were observed traces of hemoglobin - by its re-absorption at 545 and 575 nm, which distort the fluorescence spectra detected from these anatomic sites. Results, obtained in this study are foreseen to be used for development of algorithms for diagnosis and differentiation of teeth lesions and other problems of oral cavity hard tissues as periodontitis and gingivitis.

  15. Microscopic characterization of bacteria-hard tissue interactions

    NASA Astrophysics Data System (ADS)

    George, S.; Kishen, A.

    2005-08-01

    Bacterial interaction with host tissues plays a major role in the cause and persistence of diseases. It has been confirmed by different clinical investigations that Enterococcus faecalis resist root canal treatment and commonly persist in tooth with post treatment infection. The purpose of this study is to apply different microscopic techniques to study the dynamics of the E. faecalis biofilm on root-canal-dentine tissues. Method- Ten intact non-carious human maxillary molars were prepared and incubated with bacterium in nutrient media under anaerobic condition for 16 weeks. Scanning Electron Microscopy (SEM) with Energy Dispersive X-ray microanalysis (EDX), Fluorescents microscopy Light microscopy and Laser Confocal Scanning Microscopy (LCSM) were carried out to characterize the ultrastructure of biofilm. In addition Fourier Transfer Infra Red Spectroscopy (FTIR) and Von-Kossa staining and Fluorescent microscopy were also carried out to confirm the biochemical characteristics of the biofilm structure. Result- The mature biofilm formed on the root-canal wall showed a honey-comb like structure with viable cells bacterial cells inside. The EDX and FTIR analysis showed a significant increase in the levels of Calcium (Ca) and Phosphorus (P) and evidence of biomineralization of the matured biofilm.

  16. Determination of medicinal and illicit drugs in post mortem dental hard tissues and comparison with analytical results for body fluids and hair samples.

    PubMed

    Klima, Miriam; Altenburger, Markus J; Kempf, Jürgen; Auwärter, Volker; Neukamm, Merja A

    2016-08-01

    In burnt or skeletonized bodies dental hard tissue sometimes is the only remaining specimen available. Therefore, it could be used as an alternative matrix in post mortem toxicology. Additionally, analysis of dental tissues could provide a unique retrospective window of detection. For forensic interpretation, routes and rates of incorporation of different drugs as well as physicochemical differences between tooth root, tooth crown and carious material have to be taken into account. In a pilot study, one post mortem tooth each from three drug users was analyzed for medicinal and illicit drugs. The pulp was removed in two cases; in one case the tooth was root canal treated. The teeth were separated into root, crown and carious material and drugs were extracted from the powdered material with methanol under ultrasonication. The extracts were screened for drugs by LC-MS(n) (ToxTyper™) and quantitatively analyzed with LC-ESI-MS/MS in MRM mode. The findings were compared to the analytical results for cardiac blood, femoral blood, urine, stomach content and hair. In dental hard tissues, 11 drugs (amphetamine, MDMA, morphine, codeine, norcodeine, methadone, EDDP, fentanyl, tramadol, diazepam, nordazepam, and promethazine) could be detected and concentrations ranged from approximately 0.13pg/mg to 2,400pg/mg. The concentrations declined in the following order: carious material>root>crown. Only the root canal treated tooth showed higher concentrations in the crown than in the root. In post mortem toxicology, dental hard tissue could be a useful alternative matrix facilitating a more differentiated consideration of drug consumption patterns, as the window of detection seems to overlap those for body fluids and hair. PMID:26930453

  17. Laser ablation of hard tissue: correlation between the laser beam parameters and the post-ablative tissue characteristics

    NASA Astrophysics Data System (ADS)

    Serafetinides, Alexandros A.; Makropoulou, Mersini I.; Khabbaz, Maruan

    2003-11-01

    Hard dental tissue laser applications, such as preventive treatment, laser diagnosis of caries, laser etching of enamel, laser decay removal and cavity preparation, and more recently use of the laser light to enlarge the root canal during the endodontic therapy, have been investigated for in vitro and in vivo applications. Post-ablative surface characteristics, e.g. degree of charring, cracks and other surface deformation, can be evaluated using scanning electron microscopy. The experimental data are discussed in relevance with the laser beam characteristics, e.g. pulse duration, beam profile, and the beam delivery systems employed. Techniques based on the laser illumination of the dental tissues and the subsequent evaluation of the scattered fluorescent light will be a valuable tool in early diagnosis of tooth diseases, as carious dentin or enamel. The laser induced autofluorescence signal of healthy dentin is much stronger than that of the carious dentin. However, a better understanding of the transmission patterns of laser light in teeth, for both diagnosis and therapy is needed, before the laser procedures can be used in a clinical environment.

  18. Three-dimensional Micro-culture System for Tooth Tissue Engineering.

    PubMed

    Kuchler-Bopp, S; Bécavin, T; Kökten, T; Weickert, J L; Keller, L; Lesot, H; Deveaux, E; Benkirane-Jessel, N

    2016-06-01

    The arrangement of cells within a tissue plays an essential role in organogenesis, including tooth development. Progress is being made to regenerate teeth by reassociating dissociated embryonic dental cells and implanting them in vivo. In the present study, we tested the hanging drop method to study mixed epithelial-mesenchymal cell reorganization in a liquid instead of semisolid medium to see whether it could lead to tooth histogenesis and organogenesis. This method allowed the control of the proportion and number of cells to be used, and the forming microtissues showed homogeneous size. The liquid environment favored cell migrations as compared with collagen gels. Three protocols were compared. The one that sequentially combined the hanging drop and semisolid medium cultures prior to in vivo implantation gave the best results. Indeed, after implantation, teeth developed, showing a well-formed crown, mineralization of dentin and enamel, and the initiation of root formation. Vascularization and the cellular heterogeneity in the mesenchyme were similar to what was observed in developing molars. Finally, after coimplantation with a trigeminal ganglion, the dental mesenchyme, including the odontoblast layer, became innervated. The real advantage of this technique is the small number of cells required to make a tooth. This experimental model can be employed to study the development, physiology, metabolism, or toxicology in forming teeth and test other cell sources. PMID:26965424

  19. A method for rapid measurement of laser ablation rate of hard dental tissue

    NASA Astrophysics Data System (ADS)

    Perhavec, T.; Gorkič, A.; Bračun, D.; Diaci, J.

    2009-06-01

    The aim of the study reported here is the development of a new method which allows rapid and accurate in-vitro measurements of three-dimensional (3D) shape of laser ablated craters in hard dental tissues and the determination of crater volume, ablation rate and speed. The method is based on the optical triangulation principle. A laser sheet projector illuminates the surface of a tooth, mounted on a linear translation stage. As the tooth is moved by the translation stage a fast digital video camera captures series of images of the illuminated surface. The images are analyzed to determine a 3D model of the surface. Custom software is employed to analyze the 3D model and to determine the volume of the ablated craters. Key characteristics of the method are discussed as well as some practical aspects pertinent to its use. The method has been employed in an in-vitro study to examine the ablation rates and speeds of the two main laser types currently employed in dentistry, Er:YAG and Er,Cr:YSGG. Ten samples of extracted human molar teeth were irradiated with laser pulse energies from 80 mJ to the maximum available energy (970 mJ with the Er:YAG, and 260 mJ with the Er,Cr:YSGG). About 2000 images of each ablated tooth surface have been acquired along a translation range of 10 mm, taking about 10 s and providing close to 1 million surface measurement points. Volumes of 170 ablated craters (half of them in dentine and the other half in enamel) were determined from this data and used to examine the ablated volume per pulse energy and ablation speed. The results show that, under the same conditions, the ablated volume per pulse energy achieved by the Er:YAG laser exceeds that of the Er,Cr:YSGG laser in almost all regimes for dentine and enamel. The maximum Er:YAG laser ablation speeds (1.2 mm 3/s in dentine and 0.7 mm 3/s in enamel) exceed those obtained by the Er,Cr:YSGG laser (0.39 mm 3/s in dentine and 0.12 mm 3/s in enamel). Since the presented method proves to be easy to

  20. Tooth hardness increases with zinc-content in mandibles of young adult leaf-cutter ants.

    PubMed

    Schofield, Robert M S; Nesson, Michael H; Richardson, Kathleen A

    2002-12-01

    A wide variety of arthropods and members of other phyla have elevated concentrations of Zn, Mn, other heavy metals and halogens in their jaws, leg claws, and other "tools" for interacting with the environment. While measured Zn concentrations reach 25% of dry mass in scorpion stings, concentrations are often lower than this and the enriched structures are not heavily biomineralized like vertebrate teeth and the radula of mollusks. For this reason, the degree to which the inorganic components of these structures modify their mechanical properties is in question. Here we address this problem by measuring hardness during the development of Zn accumulations in ant mandibles. We found that Zn is incorporated into the mandibular teeth of leaf-cutter ants during early adult life, reaching concentrations of about 16% of dry mass. We show that the hardness of the mandibular teeth increases nearly three-fold as the adults age and that hardness correlates with Zn content ( r=0.91). We suggest that young adults rarely cut leaves partly because their mandibles are not yet rich in Zn. Zinc enrichment (along with enrichment by other heavy metals and halogens) may play an unrecognized role in the behavioral ecology and evolution of a wide variety of invertebrates. PMID:12536282

  1. Preliminary characterization of hard dental tissue ablation with femtosecond lasers

    NASA Astrophysics Data System (ADS)

    Neev, Joseph; Squier, Jeffrey A.

    1998-05-01

    Because of low operating speed and excessive collateral damage, lasers have not succeeded in replacing conventional tools in many surgical and dental applications. Recent developments now allow the new generation of amplified ultrashort pulse lasers to operate at high repetition rates and high single pulse energies. A Titanium:sapphire Chirped Pulse Regenerative Amplifier system operating at 1 KHz and 50 fs pulse duration, was used to demonstrate ultrashort pulse ablation of hard and soft tissue. Maximum ablation rates for enamel and dentin were approximately 0.650 micrometers /pulse and 1.2 micrometers /pulse respectively. Temperature measurements at both front and rear surface of a 1 mm dentin and enamel slices showed minimal increases. Scanning electron micrographs clearly show that little thermal damage is generate by the laser system. If an effective delivery system is developed, ultrashort pulse system may offer a viable alternative as a safe, low noise dental tool.

  2. Interaction of slow highly charged ions with hard dental tissue: studies of fluoride uptake and reminalization efficacy

    NASA Astrophysics Data System (ADS)

    Daskalova, A.; Kasperski, G.; Rousseau, P.; Domaracka, A.; Lawicki, A.

    2014-05-01

    TOF-SIMS mass spectroscopy data are presented on ion irradiation of hard dental tissue using a beam of 129Xe20+ (15 kV) ions delivered in the ARIBE facility by an ECR source. The investigation was focused on the mass distribution of the fragment ions. A comparison is made between the mass spectra from hard dental tissue treated by olaflur-(C27H60F2N2O3) and untreated hard dental tissue obtained under irradiation by low-energy highly-charged ions (HCIs). We found significant differences between the mass spectra of enamel after introducing amine fluoride (olaflur) and the mass spectra of pure untreated enamel. Further, we separated out the effects caused by radiation induced in the tooth enamel from those induced in dentin, which has not been performed before. In order to conduct a further detailed analysis, it is necessary to extend the research scope to include the influence of fluorine compounds on enamel and dentin.

  3. The Rachitic Tooth

    PubMed Central

    Nociti, Francisco H.; Somerman, Martha J.

    2014-01-01

    Teeth are mineralized organs composed of three unique hard tissues, enamel, dentin, and cementum, and supported by the surrounding alveolar bone. Although odontogenesis differs from osteogenesis in several respects, tooth mineralization is susceptible to similar developmental failures as bone. Here we discuss conditions fitting under the umbrella of rickets, which traditionally referred to skeletal disease associated with vitamin D deficiency but has been more recently expanded to include newly identified factors involved in endocrine regulation of vitamin D, phosphate, and calcium, including phosphate-regulating endopeptidase homolog, X-linked, fibroblast growth factor 23, and dentin matrix protein 1. Systemic mineral metabolism intersects with local regulation of mineralization, and factors including tissue nonspecific alkaline phosphatase are necessary for proper mineralization, where rickets can result from loss of activity of tissue nonspecific alkaline phosphatase. Individuals suffering from rickets often bear the additional burden of a defective dentition, and transgenic mouse models have aided in understanding the nature and mechanisms involved in tooth defects, which may or may not parallel rachitic bone defects. This report reviews dental effects of the range of rachitic disorders, including discussion of etiologies of hereditary forms of rickets, a survey of resulting bone and tooth mineralization disorders, and a discussion of mechanisms, known and hypothesized, involved in the observed dental pathologies. Descriptions of human pathology are augmented by analysis of transgenic mouse models, and new interpretations are brought to bear on questions of how teeth are affected under conditions of rickets. In short, the rachitic tooth will be revealed. PMID:23939820

  4. Odontoblasts: Specialized hard-tissue-forming cells in the dentin-pulp complex.

    PubMed

    Kawashima, Nobuyuki; Okiji, Takashi

    2016-07-01

    Odontoblasts are specialized cells that produce dentin and exhibit unique morphological characteristics; i.e., they extend cytoplasmic processes into dentinal tubules. While osteoblasts, which are typical hard-tissue-forming cells, are generated from mesenchymal stem cells during normal and pathological bone metabolism, the induction of odontoblasts only occurs once during tooth development, and odontoblasts survive throughout the lives of healthy teeth. During the differentiation of odontoblasts, signaling molecules from the inner enamel epithelium are considered necessary for the differentiation of odontoblast precursors, i.e., peripheral dental papilla cells. If odontoblasts are destroyed by severe external stimuli, such as deep caries, the differentiation of dental pulp stem cells into odontoblast-like cells is induced. Various bioactive molecules, such as non-collagenous proteins, might be involved in this process, although the precise mechanisms responsible for odontoblast differentiation have not been fully elucidated. Recently, our knowledge about the other functional activities of odontoblasts (apart from dentin formation) has increased. For example, it has been suggested that odontoblasts might act as nociceptive receptors, and surveillance cells that detect the invasion of exogenous pathogens. The regeneration of the dentin-pulp complex has recently gained much attention as a promising future treatment modality that could increase the longevity of pulpless teeth. Finally, congenital dentin anomalies, which are concerned with the disturbance of odontoblast functions, are summarized. PMID:27131345

  5. Improved classification and visualization of healthy and pathological hard dental tissues by modeling specular reflections in NIR hyperspectral images

    NASA Astrophysics Data System (ADS)

    Usenik, Peter; Bürmen, Miran; Fidler, Aleš; Pernuš, Franjo; Likar, Boštjan

    2012-03-01

    Despite major improvements in dental healthcare and technology, dental caries remains one of the most prevalent chronic diseases of modern society. The initial stages of dental caries are characterized by demineralization of enamel crystals, commonly known as white spots, which are difficult to diagnose. Near-infrared (NIR) hyperspectral imaging is a new promising technique for early detection of demineralization which can classify healthy and pathological dental tissues. However, due to non-ideal illumination of the tooth surface the hyperspectral images can exhibit specular reflections, in particular around the edges and the ridges of the teeth. These reflections significantly affect the performance of automated classification and visualization methods. Cross polarized imaging setup can effectively remove the specular reflections, however is due to the complexity and other imaging setup limitations not always possible. In this paper, we propose an alternative approach based on modeling the specular reflections of hard dental tissues, which significantly improves the classification accuracy in the presence of specular reflections. The method was evaluated on five extracted human teeth with corresponding gold standard for 6 different healthy and pathological hard dental tissues including enamel, dentin, calculus, dentin caries, enamel caries and demineralized regions. Principal component analysis (PCA) was used for multivariate local modeling of healthy and pathological dental tissues. The classification was performed by employing multiple discriminant analysis. Based on the obtained results we believe the proposed method can be considered as an effective alternative to the complex cross polarized imaging setups.

  6. Why wavelength and delivery systems are the most important factors in using a dental hard-tissue laser: a literature review.

    PubMed

    Bornstein, Eric S

    2003-11-01

    Various lasers have been investigated in the dental clinic as an alternative to the dental drill for the treatment of dental hard tissues. Among the lasers, the erbium-based solid-state infrared lasers, operating at approximately 3 microm, have demonstrated they are effective in dental applications because of their high affinity for water in the hydroxyapatite of the tooth structure. Water is the dominant chromophore that absorbs the laser energy during hard-tissue treatment; this leads to well-established, mechanical, thermally driven, and explosive ablation, which is the basis for the erbium laser-tissue interaction. A review of the literature presents a number of studies in which the superior qualities of the Er:YAG laser, in particular, are demonstrated. Er:YAG irradiation results in the least amount of temperature increase at the laser-tooth interface. The Er:YAG laser generates photons with the strongest absorption by water in the enamel and dentin and, when combined with a water cooling spray, produces extremely minor zones of carbonization, debris, and necrosis after irradiation. Furthermore, the Er:YAG laser wavelength can be easily delivered with a hollow waveguide delivery system and contact sapphire tip, resulting in a more precise cavity preparation than other delivery systems. The Er:YAG laser system offers the optimal wavelength and the ability to be transmitted in the most efficient manner for successful dental hard-tissue ablation. PMID:18624131

  7. Tooth Eruption Results from Bone Remodelling Driven by Bite Forces Sensed by Soft Tissue Dental Follicles: A Finite Element Analysis

    PubMed Central

    Sarrafpour, Babak; Swain, Michael; Li, Qing; Zoellner, Hans

    2013-01-01

    Intermittent tongue, lip and cheek forces influence precise tooth position, so we here examine the possibility that tissue remodelling driven by functional bite-force-induced jaw-strain accounts for tooth eruption. Notably, although a separate true ‘eruptive force’ is widely assumed, there is little direct evidence for such a force. We constructed a three dimensional finite element model from axial computerized tomography of an 8 year old child mandible containing 12 erupted and 8 unerupted teeth. Tissues modelled included: cortical bone, cancellous bone, soft tissue dental follicle, periodontal ligament, enamel, dentine, pulp and articular cartilage. Strain and hydrostatic stress during incisive and unilateral molar bite force were modelled, with force applied via medial and lateral pterygoid, temporalis, masseter and digastric muscles. Strain was maximal in the soft tissue follicle as opposed to surrounding bone, consistent with follicle as an effective mechanosensor. Initial numerical analysis of dental follicle soft tissue overlying crowns and beneath the roots of unerupted teeth was of volume and hydrostatic stress. To numerically evaluate biological significance of differing hydrostatic stress levels normalized for variable finite element volume, ‘biological response units’ in Nmm were defined and calculated by multiplication of hydrostatic stress and volume for each finite element. Graphical representations revealed similar overall responses for individual teeth regardless if incisive or right molar bite force was studied. There was general compression in the soft tissues over crowns of most unerupted teeth, and general tension in the soft tissues beneath roots. Not conforming to this pattern were the unerupted second molars, which do not erupt at this developmental stage. Data support a new hypothesis for tooth eruption, in which the follicular soft tissues detect bite-force-induced bone-strain, and direct bone remodelling at the inner surface of

  8. Photodynamic Inactivation of Root Canal Bacteria by Light Activation through Human Dental Hard and Simulated Surrounding Tissue

    PubMed Central

    Cieplik, Fabian; Pummer, Andreas; Leibl, Christoph; Regensburger, Johannes; Schmalz, Gottfried; Buchalla, Wolfgang; Hiller, Karl-Anton; Maisch, Tim

    2016-01-01

    Introduction: Photodynamic inactivation of bacteria (PIB) may be a supportive antimicrobial approach for use in endodontics, but sufficient activation of photosensitizers (PS) in root canals is a critical point. Therefore, aim of this study was to evaluate the ability of PS absorbing blue (TMPyP) or red light (Methylene Blue; MB) for light activation through human dental hard and simulated surrounding tissue to inactivate root canal bacteria. Methods: A tooth model was fabricated with a human premolar and two molars in an acrylic resin bloc simulating the optical properties of a porcine jaw. The distal root canal of the first molar was enlarged to insert a glass tube (external diameter 2 mm) containing PS and stationary-phase Enterococcus faecalis. Both PS (10 μM) were irradiated for 120 s with BlueV (20 mW/cm2; λem = 400–460 nm) or PDT 1200L (37.8 mW/cm2; λem = 570–680 nm; both: Waldmann Medizintechnik), respectively. Irradiation parameters ensured identical numbers of photons absorbed by each PS. Three setups were chosen: irradiating the glass pipette only (G), the glass pipette inside the single tooth without (GT) and with (GTM) simulated surrounding tissues. Colony forming units (CFU) were evaluated. Transmission measurements of the buccal halves of hemisected mandibular first molars were performed by means of a photospectrometer. Results: PIB with both PS led to reduction by ≥ 5 log10 of E. faecalis CFU for each setup. From transmission measurements, a threshold wavelength λth for allowing an amount of light transmission for sufficient activation of PS was determined to be 430 nm. Conclusion: This study can be seen as proof of principle that light activation of given intra-canal PS from outside a tooth may be possible at wavelengths ≥ 430 nm, facilitating clinical application of PIB in endodontics. PMID:27379059

  9. Effect of erbium, chromium: yttrium, scandium, gallium, garnet laser and casein phosphopeptide-amorphous calcium phosphate on surface micro-hardness of primary tooth enamel

    PubMed Central

    Subramaniam, Priya; Pandey, Annu

    2014-01-01

    Objective: The aim was to evaluate the effect of Er, Cr: YSGG laser and casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) on surface micro-hardness of primary tooth enamel. Materials and Methods: A total of 30 freshly extracted caries free primary anterior teeth were cleaned and stored in 1% thymol. Teeth were embedded in acrylic resin such that only their buccal surfaces were exposed and were divided into four groups. Group I: Five intact teeth (negative control). The remaining 25 teeth were immersed for 30 min in 1% citric acid for demineralization. Group II: Five demineralized teeth (positive control), Group III: CPP-ACP (GC tooth mousse-GC International, Itabashi-Ku, Tokyo, Japan) application and Group IV: Etching using Er, Cr: YSGG laser + CPP-ACP application. Groups III and IV were subjected to pH cycling for 5 days. Surface micro-hardness of all the teeth was measured using Brinell hardness tester (Fuel Instruments and Engineers Pvt. Ltd.). Data were analyzed using ANOVA. Results: Mean surface micro-hardness of Groups I and II were 177.43 kgf/mm2 and 164.86 kgf/mm2, respectively. Group IV showed a higher mean surface micro-hardness (230.68 kgf/mm2) compared with that of Group III (190.28 kgf/mm2). In comparison to all other groups, laser etching prior to CPP-ACP application increased surface micro-hardness significantly (P < 0.001). Conclusion: Laser irradiation of primary teeth followed by CPP-ACP application increased surface micro-hardness of enamel. PMID:25202223

  10. Expression of ATF4 and RUNX2 in periodontal tissue of pressure side during orthodontic tooth movement in rat

    PubMed Central

    Han, Jinyou; Xu, Xiaodong; Zhang, Bin; Chen, Baoxing; Hang, Wangyan

    2015-01-01

    Objective: This study aims to explore the expression levels of ATF4 and RUNX and their interactions in periodontal tissue of the pressure side during orthodontic tooth movement. Methods: A total of 72 SPF level male Sprague Dawley rats were used in this study, they were divided into 9 groups randomly and 8 rats in each group. The expression changes of ATF4 and RUNX2 in periodontal tissue of pressure side at different straining time point were detected with RT-PCR and Western blotting methods. The morphological changes of cells in the tissue samples were observed by HE staining. The data were analyzed with SPSS 19.0 software. Results: The expression levels of ATF4 and RUNX2 increased during orthodontic tooth movement and were related with the movement time. They reached highest after straining for 24 h and began to decrease after straining for 12 d. Conclusions: The expression levels of ATF4 and RUNX2 in periodontal tissue can increase transiently induced by stress, which play a role in the process of osteogenesis and reconstruction of periodontal tissue during orthodontic tooth movement. PMID:25785078

  11. Lasers in Esthetic Dentistry: Soft Tissue Photobiomodulation, Hard Tissue Decontamination, and Ceramics Conditioning

    PubMed Central

    Ramalho, Karen Müller; de Freitas, Patrícia Moreira; Correa-Aranha, Ana Cecília; Bello-Silva, Marina Stella; Lopes, Roberta Marques da Graça; Eduardo, Carlos de Paula

    2014-01-01

    The increasing concern and the search for conservative dental treatments have resulted in the development of several new technologies. Low and high power lasers can be cited as one of these new technologies. Low power lasers act at cellular level leading to pain reduction, modulation of inflammation, and improvement of tissue healing. High power lasers act by increasing temperature and have the potential to promote microbial reduction and ablation of hard and soft tissues. The clinical application of both low and high power lasers requires specific knowledge concerning laser interaction with biological tissues, so that the correct irradiation protocol can be established. The present case report describes the clinical steps of two metal-ceramic crowns development in a 60-year-old patient. Three different laser wavelengths were applied throughout the treatment with different purposes: Nd:YAG laser (1,064 nm) for dentin decontamination, diode (660 nm) for soft tissue biomodulation, and Er:YAG laser (2,940 nm) for inner ceramic surface conditioning. Lasers were successfully applied in the present case report as coadjutant in the treatment. This coadjutant technology can be a potential tool to assist treatment to reach the final success. PMID:25147746

  12. Tooth brushing, oil pulling and tissue regeneration: A review of holistic approaches to oral health.

    PubMed

    Singh, Abhinav; Purohit, Bharathi

    2011-04-01

    Even though dentistry was not a specialized branch of Ayurveda, it is included in its Shalakya Tantra (system of surgery). Problems such as deformities of the oral cavity, plaques and infections were managed in ancient India. Traditional medicine can treat various infectious and chronic conditions. Research has shown that all kinds of chewing sticks described in ancient Ayurveda texts have medicinal and anti-cariogenic properties. Its oil pulling (Kaval, Gandush) practice is claimed to cure about 30 systemic diseases. Amla (Emblic myrobalan), is a general rebuilder of oral health. Bilberry fruit (Vaccinium myrtillus) and hawthorn berry (Crateagus oxycanthus) stabilize collagen, strengthening the gum tissue. Liquorice root (Glycyrrhiza glabral) promotes anti-cavity action, reduces plaque, and has an antibacterial effect. Use of safe, quality products and practices should be ensured based on available evidence if traditional medicine is to be acknowledged as part of primary health care. Scientific validations of the Ayurveda dental health practices could justify their incorporation into modern dental care. Publicity of these techniques using appropriate media would benefit the general population by giving more confidence in the ancient practices, thus preventing tooth decay and loss. PMID:21760690

  13. Tooth brushing, oil pulling and tissue regeneration: A review of holistic approaches to oral health

    PubMed Central

    Singh, Abhinav; Purohit, Bharathi

    2011-01-01

    Even though dentistry was not a specialized branch of Ayurveda, it is included in its Shalakya Tantra (system of surgery). Problems such as deformities of the oral cavity, plaques and infections were managed in ancient India. Traditional medicine can treat various infectious and chronic conditions. Research has shown that all kinds of chewing sticks described in ancient Ayurveda texts have medicinal and anti-cariogenic properties. Its oil pulling (Kaval, Gandush) practice is claimed to cure about 30 systemic diseases. Amla (Emblic myrobalan), is a general rebuilder of oral health. Bilberry fruit (Vaccinium myrtillus) and hawthorn berry (Crateagus oxycanthus) stabilize collagen, strengthening the gum tissue. Liquorice root (Glycyrrhiza glabral) promotes anti-cavity action, reduces plaque, and has an antibacterial effect. Use of safe, quality products and practices should be ensured based on available evidence if traditional medicine is to be acknowledged as part of primary health care. Scientific validations of the Ayurveda dental health practices could justify their incorporation into modern dental care. Publicity of these techniques using appropriate media would benefit the general population by giving more confidence in the ancient practices, thus preventing tooth decay and loss. PMID:21760690

  14. Dynamics of water-mediated hard dental tissue ablation with Ho:YAG laser visualized by high speed photography

    NASA Astrophysics Data System (ADS)

    Zhan, Zhenlin; Chen, Chuanguo; Li, Xuwei; Zhang, Xianzeng; Xie, Shusen

    2015-03-01

    The goal of this study was to evaluate the dynamic process of water-mediated hard dental tissue ablation induced by Ho:YAG laser with high-speed camera. Human molars in vitro of yellow race were cut into tooth sections and irradiated with pulsed Ho:YAG laser with a wavelength of 2.08μm. The pulse repetition rate was 3 Hz and laser energy ranged from 300 to 2000 mJ. The frame rate of high-speed camera used in the experiment was 50525 fps. Based on the observation by high-speed camera, the dynamic process of the oscillating cavitation bubble and water-mediated ablation induced by Ho:YAG laser was efficiently recorded and graphically described. The pulsation period, the maximum length and width of vapor channel increased with laser energy. The results showed that the external water played multiple roles in laser ablation of hard dental tissue, not only acting as a channel to transmit laser energy, but also helping to improve the regularity of the ablation shape.

  15. Hardness Changes of Tissue Conditioners in Various Storage Media: An in Vitro Study.

    PubMed

    Ntounis, Athanasios; Kamposiora, Phophi; Papavasiliou, George; Divaris, Kimon; Zinelis, Spiros

    2015-03-01

    The aim of the present study was to evaluate the effects of storage media on the longitudinal hardness changes of tissue conditioning materials. Four tissue-conditioning materials were used for fabrication of 80 disc-shaped specimens and divided in four groups, stored in four storage media. The specimens underwent artificial ageing corresponding to 30 nights of extra-oral storage. Hardness measurements were obtained at nine intervals between 8 and 240 hours after specimen fabrication. To test the effects of storage media on hardness we employed multivariate modelling (Bonferroni correction; α = 0.05). The materials exhibited varying hardness changes, most pronounced when stored in ambient air. PMID:26415333

  16. Tissue mimicking materials for dental ultrasound.

    PubMed

    Singh, Rahul S; Culjat, Martin O; Grundfest, Warren S; Brown, Elliott R; White, Shane N

    2008-04-01

    While acoustic tissue mimicking materials have been explored for a variety of soft and hard biological tissues, no dental hard tissue mimicking materials have been characterized. Tooth phantoms are necessary to better understand acoustic phenomenology within the tooth environment and to accelerate the advancement of dental ultrasound imaging systems. In this study, soda lime glass and dental composite were explored as surrogates for human enamel and dentin, respectively, in terms of compressional velocity, attenuation, and acoustic impedance. The results suggest that a tooth phantom consisting of glass and composite can effectively mimic the acoustic behavior of a natural human tooth. PMID:18396919

  17. Reliability and validity of an instrument to measure tissue hardness in breasts.

    PubMed

    Roberts, K L

    The author investigated the effectiveness of the Roberts Durometer, an instrument developed to measure human tissue hardness for a study on breast engorgement. The instrument is a small portable pressure gauge comprising a probe attached to a spring and contained in a tubular housing, connected to a dial gauge. The instrument was first trialed using foam rubber of differing hardness and football bladders of differing hardness. It was then used to measure the hardness of a non-pregnant, non-lactating human breast, followed by trials on postpartum women comparing breast tissue hardness on the day of birth with that of subsequent days. The instrument detected significant differences in hardness of foams, football bladders and human breast tissue. It was therefore considered suitable for measuring, in both research and clinical applications, hardness of breast tissue, which is a major physical feature of breast engorgement. Other clinical applications could include the hardness of abdominal and other skin tissues in conditions such as ascites, peritonitis and cellulitis. PMID:10196872

  18. Concentrations of 90Sr in the tooth tissues 60 years after intake: results of TL measurements and applications for Techa River dosimetry.

    PubMed

    Shishkina, E A; Tolstykh, E I; Verdi, E; Volchkova, A Yu; Veronese, I; El-Faramawy, N A; Göksu, H Y; Degteva, M O

    2014-03-01

    This article focuses on the study of (90)Sr in the tooth tissues of Techa riverside residents 60 years after intake. The Techa River was contaminated by radioactive wastes in the 1950s. Contamination of the river system, including water, bottom sediment, floodplain soil, and grass, depended on the distance from the source of releases. Therefore, the average (90)Sr intake was different in different settlements located downstream the river. An additional factor influencing (90)Sr accumulation in the teeth is the rate of tissue mineralization at the time of intake which depended on the donor's age at the time of releases. Measurements of (90)Sr concentration in various dental tissues (enamel, crown, and root dentin) of 166 teeth were performed about 60 years after the main intake using the method of thermoluminescence passive beta detection. The paper presents the current levels of tooth tissue contamination, and the tooth-to-tooth variability of (90)Sr concentration in tooth tissues was assessed for the tissues which were matured at the time of massive liquid radioactive waste releases into the Techa River. A model describing the expected levels of (90)Sr in matured dental tissues depending on age and intake has been elaborated for the population under study. The results obtained will be used for calculation of internal dose in enamel and for interpretation of tooth doses measured by means of the electron paramagnetic resonance method, among the population of the Techa River region. PMID:24292426

  19. ABO blood grouping from hard and soft tissues of teeth by modified absorption-elution technique

    PubMed Central

    Ramnarayan, BK; Manjunath, M; Joshi, Anagha Ananth

    2013-01-01

    Background: Teeth have always been known as stable tissue that can be preserved both physically and chemically for long periods of time. Blood group substances have been known to be present in both the hard and soft tissues of the teeth. Objectives: This study aimed at detection of ABO blood group substances from soft and hard tissues of teeth and also to evaluate the reliability of teeth stored for a relatively long period as a source of blood group substances by absorption–elution technique with some modifications. Results: Blood group obtained from the teeth was compared with those obtained from the blood sample. Pulp showed a very large correlation in both fresh and long-standing teeth though it decreased slightly in the latter. Hard tissue showed a large correlation in both the groups indicating that hard tissue is quite reliable to detect blood group and that there is no much difference in the reliability in both the groups. However, combining pulp and hard tissue, correlation is moderate. Correlation of blood grouping with the age, sex, and jaw distribution was carried out. Conclusion: Blood group identification from hard and soft tissues of teeth aids in the identification of an individual. PMID:23960412

  20. Two-photon-excited autofluorescence and second-harmonic generation microscopy for the visualization of penetration of TiO2 and ZnO nanoparticles into human tooth tissue ex vivo

    NASA Astrophysics Data System (ADS)

    Trunina, Natalia A.; Popov, Alexey P.; Lademann, Jürgen; Tuchin, Valery V.; Myllylä, Risto; Darvin, Maxim E.

    2012-06-01

    Penetration of nanoparticles into tooth tissues is of significant interest in solving problems related to reduction of tooth sensitivity, enamel strengthening and restoration and cosmetic bleaching. In this work we demonstrate two-photonexcited autofluorescence and second-harmonic generation microscopy for visualization of penetration of TiO2 and ZnO nanoparticles into tooth tissues.

  1. New method for determination of ablation of dental hard tissues with the Er:YAG laser

    NASA Astrophysics Data System (ADS)

    Wigdor, Harvey A.; Walsh, Joseph T., Jr.; Cummings, Joseph P.

    1993-07-01

    It seems that the dental profession will not embrace the laser for dentistry until hard tissue applications are developed. To date the lasers that are available for dentists in the clinical setting have little scientific basis for use on dental hard tissues. Before a viable laser method becomes available for dental hard tissues, basic research on the correlation of incident fluence to hard tissue removal must be studied. In this paper we propose a method of determining the exact size and shape of the defect created by an Er:YAG laser and correlate the size, depth, and volume of the defect relative to the fluence, spot size and number of pulses of the Er:YAG laser.

  2. Fatigue and fatigue crack growth processes in hard tissues: The importance of age and surface integrity

    NASA Astrophysics Data System (ADS)

    Majd, Hessam

    With the progressive increase in partially and fully dentate seniors, fracture has become an increasingly common form of restored tooth failure. Dentin undergoes progressive changes in microstructure with patient age, and studies are now suggesting that there is a reduction in fatigue strength and fatigue crack growth resistance of this tissue. This dissertation explores aging of dentin, the influence of flaws that are introduced during restorative processes on the fatigue properties of dentin, and proposes models for characterizing the damage initiation and growth process during fatigue of dentin. Results from this investigation show that the fatigue crack growth properties (Paris Law parameters (C, m) andDeltaKth) of human dentin undergo the most significant changes at a patient age of 42 years. Based on the fatigue crack growth responses, three age groups were established including young (age≤33), aged (34≤age ≤49) and old (50≤age) patients for further analysis. There were significant differences in the initiation and growth behavior between the tissues of patients from the three age groups. With regards to the influence of restorative processes, there was no influence on the quasi-static responses of dentin. However, the endurance limit of dentin treated with the dental burs (28 MPa) and abrasive air jet (35 MPa) were approximately 36% and 20% lower than that of the control (44 MPa), respectively. Both cutting processes caused a significant reduction (p≤0.0001) in fatigue strength. An accumulative damage model was developed to characterize fatigue of the control and bur treated dentin as well as provide a model for fatigue life prediction. The damage models were derived as a function of number of loading cycles (N), and ratio of applied stress to ultimate strength (r). The developed models provide estimations for the initial state of damage, the state of damage during the life, as well as the damage accumulation rate for cyclic loading of dentin

  3. Phase Transformations in a Human Tooth Tissue at the Initial Stage of Caries

    PubMed Central

    Prutskij, Tatiana; Ippolitov, Yury

    2015-01-01

    The aim of the paper is to study phase transformations in solid tissues of the human teeth during the development of fissure caries by Raman and fluorescence microspectroscopy. The study of the areas with fissure caries confirmed the assumption of the formation of a weak interaction between phosphate apatite enamel and organic acids (products of microorganisms). The experimental results obtained with by Raman microspectroscopy showed the formation of dicalcium phosphate dihydrate - CaHPO4-2H2O in the area of mural demineralization of carious fissure. A comparative analysis of structural and spectroscopic data for the intact and carious enamel shows that emergence of a more soluble phase - carbonate-substituted hydroxyapatite - is typical for the initial stage of caries. It is shown that microareas of dental hard tissues in the carious fissure due to an emerging misorientation of apatite crystals have a higher fluorescence yield than the area of the intact enamel. These areas can be easily detected even prior to a deep demineralization (white spot stage) for the case of irreversibly changed organomineral complex and intensive removal of the mineral component. PMID:25901743

  4. Novel use of the CO2 laser on dental hard tissues: an SEM study

    NASA Astrophysics Data System (ADS)

    Wigdor, Harvey A.; Gilbert, Jeremy L.; Chomsky, Doron; Raif, Joshua

    1997-05-01

    There is great interest in dentistry to find a replacement for the dental drill which is a great source fear in dental patients. Lasers have been considered a potential replacement. Hard tissue use of lasers on dental tissues has been slow in development has had very limited acceptance by the dental community. The ultimate goal is to develop a laser which can remove both healthy and diseased dental hard tissues and dental materials. The CO2 laser surgical applications on sot tissues has been reported by many authors. It is hard tissue applications have had very few published reports. The thermal effects of this laser on hard tissues precluded its use on hard tissues. A new CO2 laser has been developed to reduce the thermal effects on dentin and enamel. Powers of 3-5 watts were used to ablate the buccal surface of extracted human molar teeth. These teeth were gold coated and evaluated under scanning electron microscopy. The results show some melting of the dentin and enamel, however patent dentinal tubules are evident and there appears to be a non-thermal cutting of the enamel at the boarder of the cut surface. In conclusion these very preliminary results appear to show that this new CO2 laser can cut dentin and enamel efficiently and with very little thermal effect as seen under SEM.

  5. Clinical measurement of tooth wear: Tooth wear indices

    PubMed Central

    López-Frías, Francisco J.; Castellanos-Cosano, Lizett; Martín-González, Jenifer; Llamas-Carreras, José M.

    2012-01-01

    Attrition, erosion, and abrasion result in alterations to the tooth and manifest as tooth wear. Each classification corresponds to a different process with specific clinical features. Classifications made so far have no accurate prevalence data because the indexes do not necessarily measure a specific etiology, or because the study populations can be diverse in age and characteristics. Tooth wears (attrition, erosion and abrasion) is perceived internationally as a growing problem. However, the interpretation and comparison of clinical and epidemiological studies, it is increasingly difficult because of differences in terminology and the large number of indicators/indices that have been developed for the diagnosis, classification and monitoring of the loss of dental hard tissue. These indices have been designed to identify increasing severity and are usually numerical, none have universal acceptance, complicating the evaluation of the true increase in prevalence reported. This article considers the ideal requirements for an erosion index. A literature review is conducted with the aim of analyzing the evolution of the indices used today and discuss whether they meet the clinical needs and research in dentistry. Key words:Tooth wear, tooth wear indices, attrition, erosion, abrasion, abfraction. PMID:24558525

  6. 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.

  7. A comparison between adipose tissue and dental pulp as sources of MSCs for tooth regeneration.

    PubMed

    Hung, Chia-Nung; Mar, Kwei; Chang, Hao-Chen; Chiang, Yi-Lun; Hu, Huai-Yun; Lai, Chia-Chi; Chu, Rei-Min; Ma, Chang M

    2011-10-01

    In this study, several in vivo and in vitro comparisons were performed to test the possibility of using adipose-derived stem cells (ADSCs), a more convenient cell source than dental pulp stem cells (DPSCs), in tooth regeneration. Using an efficient, non-engineering implantation method, we first demonstrated that both implants of ADSCs and DPSCs were able to grow self-assembled new teeth in adult rabbit extraction sockets with high success rate. The stem cells were necessary because the implants grew no tooth without them. A stepwise comparison showed that the regenerated teeth from these two types of adult stem cells were living with nerves and vascular system and remarkably similar to a normal tooth in many details. Further strictly controlled, side-by-side comparisons between the two types of stem cells also showed that the expression patterns of gene markers and the broad differentiation potentials induced by specific methods in vitro were very similar. Although a few differences were found, they did not affect the tested tooth regeneration in vivo or differentiation in vitro. Furthermore, rabbit ADSCs had a higher growth rate and a better senescence resistance in culture. All these findings suggest that ADSCs, one of the richest adult stem cells in mammals, are very similar and useful as DPSCs for regenerative dentistry. PMID:21696818

  8. Picosecond and femtosecond laser ablation of hard tissues

    NASA Astrophysics Data System (ADS)

    Serafetinides, Alexander A.; Makropoulou, Mersini I.; Kar, Ajoy K.; Khabbaz, Marouan

    1996-12-01

    In this study, the interaction of picosecond and femtosecond pulsed laser radiation with human dental tissue was investigated experimentally, as this unexplored field is expected to be a potential alternative in powerful laser processing of biomedical structures. Dentin ablation rate experiments were performed by using teeth sections of different thickness. Dental tissue samples were irradiated in air with i) a regenerative amplifier laser at 1064 nm, pulse duration 110 ps, ii) the second harmonic laser at 532 nm, pulse duration 100 ps, and iii) a picosecond tunable dye amplifier at 595 nm, pulse width 800 fs. In all the experiments the pulse repetition rate was 10 Hz. The ablation rate per pulse at different energy fluence settings was calculated by measuring the time needed for the perforation of the whole dental sample thickness. Short laser pulses can confine thermal energy within the optical zone, which maximizes photothermal and photomechanical mechanisms of interaction. Tissue ablation rates were found to be comparable to or better than other nanosecond lasers, and left smooth surfaces, free of thermal damage.

  9. Effects of pulsed lasers on hard biological tissue

    NASA Astrophysics Data System (ADS)

    Jahn, Renate; Bleckmann, Andreas; Duczynski, Edwin W.; von der Heide, Hans-Joachim; Huber, Guenter; Jungbluth, Karl-Heinz; Lierse, Werner; Neu, Walter; Struve, Bert

    1993-07-01

    The interaction of various pulsed lasers with meniscus and bone of freshly slaughtered bovines and pigs was examined. Our aim was to find lasers useful for accident surgical operations (e.g. bone or callus dystopy inside joints or nearby important vessels or nerves after fractures). Laser wavelengths of the UV- and infrared spectral range were investigated: XeCl- excimer lasers (wavelength 308 nm, pulse duration 28 ns, 60 ns, 300 ns) Nd:YAG (1.06 micrometers , 400 microsecond(s) ), Tm:YAG (2.01 micrometers , 400 microsecond(s) ), Ho:YAG (2.12 micrometers , 400 microsecond(s) ), CrEr:YSGG (2.79 micrometers , 400 microsecond(s) ), and Er:YAG (2.94 micrometers , 400 microsecond(s) ). The excimer laser radiation was guided by a tapered fused silica fiber, whereas for all other lasers the tissue samples were positioned in the focus of a lens with 100 mm focal length. Ablation rates were determined by perforating samples of defined thickness, and the effects of laser ablation on tissue were controlled macroscopically, by light microscopy and by scanning electron microscopy.

  10. Development of oral osteomucosal tissue constructs in vitro and localization of fluorescently-labeled bisphosphonates to hard and soft tissue

    PubMed Central

    BAE, SUSAN; SUN, SHUTING; AGHALOO, TARA; OH, JU-EUN; McKENNA, CHARLES E.; KANG, MO K.; SHIN, KI-HYUK; TETRADIS, SOTIRIOS; PARK, NO-HEE; KIM, REUBEN H.

    2014-01-01

    Bisphosphonates (BPs) are anti-resorptive agents commonly used to treat bone-related diseases; however, soft tissue-related side-effects are frequently reported in some BP users, such as oral or gastrointestinal (GI) ulcerations. BPs are stable analogs of pyrophosphate and have high affinity to hydroxyapatite, allowing them to bind to the bone surfaces and exert suppressive effects on osteoclast functions. However, the underlying mechanisms as to how bone-seeking BPs also exert cytotoxic effects on soft tissue remain unknown. In the present study, we investigated the localization of nitrogen-containing BPs (N-BPs) in hard and soft tissue using fluorescently-labeled N-BPs in vitro. We developed osteomucosal tissue constructs in vitro to recapitulate the hard and soft tissue of the oral cavity. A histological examination of the osteomucosal tissue constructs revealed a differentiated epithelium over the bone containing osteocytes and the periosteum, similar to that observed in the rat palatal tissues. Following treatment with the fluorescently-labeled bisphosphonate, AF647-ZOL, the osteomucosal constructs exhibited fluorescent signals, not only in the bone, but also in the epithelium. No fluorescent signals were observed from the control- or ZOL-treated constructs, as expected. Collectively, the data from the present study suggest that N-BPs localize to epithelial tissue and that such a localization and subsequent toxicity of N-BPs may be associated, at least in part, with soft tissue-related side-effects. PMID:24920042

  11. Dental hard tissue modification and removal using sealed TEA lasers operating at λ=9.6 and 10.6 μm

    NASA Astrophysics Data System (ADS)

    Fried, Daniel; Murray, Michael W.; Featherstone, John D. B.; Akrivou, Maria; Dickenson, Kevin M.; Duhn, Clifford W.; Ojeda, Orlando P.

    1999-05-01

    Pulsed CO2 lasers have been shown to be effective for both removal and modification of dental hard tissue for the treatment of dental caries. In this study, sealed TEA laser systems optimally tuned to the highly absorbed 9.6 μm wavelength were investigated for application on dental hard tissue. Conventional TEA lasers produce a laser pulse wit a 100-200 ns gain switched spike followed by a long tail of about 1-4 μs in duration. the pulse duration is well matched to the 1-2 μs thermal relaxation time of the deposited laser energy at 9.6 μm and effectively heats the enamel to temperatures required for surface modification for caries prevention at absorbed fluences of less than 0.5 J/cm2. Thus, the heat deposition in the tooth and the corresponding risk, of pulpal necrosis form excessive heat accumulation is minimized. At higher fluences the high peak power of the gain-switched spike rapidly initiates a plasma that markedly reduces the ablation rate and efficiency, severely limiting applicability for hard tissue ablation. By slightly stretching the pulse to reduce the energy distributed in the initial 100-200 ns of the laser pulse, the plasma threshold can be raised sufficiently to increase the ablation rate by an order of magnitude. This results in a practical and efficient CO2 laser system for caries ablation and surface modification.

  12. Dental hard tissue modification and removal using sealed transverse excited atmospheric-pressure lasers operating at lambda=9.6 and 10.6 um

    NASA Astrophysics Data System (ADS)

    Fried, Daniel; Ragadio, Jerome N.; Akrivou, Maria; Featherstone, John D.; Murray, Michael W.; Dickenson, Kevin M.

    2001-04-01

    Pulsed CO2 lasers have been shown to be effective for both removal and modification of dental hard tissue for the treatment of dental caries. In this study, sealed transverse excited atmospheric pressure (TEA) laser systems optimally tuned to the highly absorbed 9.6 micrometers wavelength were investigated for application on dental hard tissue. Conventional TEA lasers produce an initial high energy spike at the beginning of the laser pulse of submicrosecond duration followed by a long tail of about 1 - 4 microsecond(s) . The pulse duration is well matched to the 1 - 2 microsecond(s) thermal relaxation time of the deposited laser energy at 9.6 micrometers and effectively heats the enamel to the temperatures required for surface modification at absorbed fluences of less than 0.5 J/cm2. Thus, the heat deposition in the tooth and the corresponding risk of pulpal necrosis from excessive heat accumulation is minimized. At higher fluences, the high peak power of the laser pulse rapidly initiates a plasma that markedly reduces the ablation rate and efficiency, severely limiting applicability for hard tissue ablation. By lengthening the laser pulse to reduce the energy distributed in the initial high energy spike, the plasma threshold can be raised sufficiently to increase the ablation rate by an order of magnitude. This results in a practical and efficient CO2 laser system for caries ablation and surface modification.

  13. Hard and soft tissue correlations in facial profiles: a canonical correlation study

    PubMed Central

    Shamlan, Manal A; Aldrees, Abdullah M

    2015-01-01

    Background The purpose of this study was to analyze the relationship between facial hard and soft tissues in normal Saudi individuals by studying the canonical correlation between specific hard tissue landmarks and their corresponding soft tissue landmarks. Methods A retrospective, cross-sectional study was designed, with a sample size of 60 Saudi adults (30 males and 30 females) who had a class I skeletal and dental relationship and normal occlusion. Lateral cephalometric radiographs of the study sample were investigated using a series of 29 linear and angular measurements of hard and soft tissue features. The measurements were calculated electronically using Dolphin® software, and the data were analyzed using canonical correlation. Results Eighty-four percent of the variation in the soft tissue was explained by the variation in hard tissue. Conclusion The position of the upper and lower incisors and inclination of the lower incisors influence upper lip length and lower lip position. The inclination of the upper incisors is associated with lower lip length. PMID:25624772

  14. Application of 4-META/MMA-TBB resin for fixation of membrane to tooth in guided tissue regeneration in dog.

    PubMed

    Tomita, Sachiyo; Yamamoto, Shigeki; Shibukawa, Yoshihiro; Kaneko, Tadashi; Miyakoshi, Shoichi; Shimono, Masaki; Yamada, Satoru

    2010-11-01

    The aim of this study was to evaluate 4-META/MMA-TBB resin as an alternative to sling sutures for fixation of membrane to tooth in GTR in terms of its effect on tissue regeneration. Dehiscence periodontal defects were created in 6 dogs which were divided at random into two groups, 3 dogs in each group: an experimental group, in which non-absorbable or absorbable membrane was fixed to the teeth with 4-META/MMA-TBB resin; and a control group, in which sling sutures were applied to fix the two types of membrane. Histologic and histometric evaluation was carried out at 8 weeks post-operatively to determine healing response in each group. Both methods of achieving membrane fixation to tooth were effective in inhibiting epithelial migration and encouraging formation of regenerated periodontal tissues around the root surfaces. These results suggest that 4-META/MMA-TBB resin is as effective as sling sutures in achieving membrane fixation in GTR and is, moreover, easier to apply. PMID:21099162

  15. Hard tissue regeneration using bone substitutes: an update on innovations in materials

    PubMed Central

    Sarkar, Swapan Kumar

    2015-01-01

    Bone is a unique organ composed of mineralized hard tissue, unlike any other body part. The unique manner in which bone can constantly undergo self-remodeling has created interesting clinical approaches to the healing of damaged bone. Healing of large bone defects is achieved using implant materials that gradually integrate with the body after healing is completed. Such strategies require a multidisciplinary approach by material scientists, biological scientists, and clinicians. Development of materials for bone healing and exploration of the interactions thereof with the body are active research areas. In this review, we explore ongoing developments in the creation of materials for regenerating hard tissues. PMID:25995658

  16. Hard tissue regeneration using bone substitutes: an update on innovations in materials.

    PubMed

    Sarkar, Swapan Kumar; Lee, Byong Taek

    2015-05-01

    Bone is a unique organ composed of mineralized hard tissue, unlike any other body part. The unique manner in which bone can constantly undergo self-remodeling has created interesting clinical approaches to the healing of damaged bone. Healing of large bone defects is achieved using implant materials that gradually integrate with the body after healing is completed. Such strategies require a multidisciplinary approach by material scientists, biological scientists, and clinicians. Development of materials for bone healing and exploration of the interactions thereof with the body are active research areas. In this review, we explore ongoing developments in the creation of materials for regenerating hard tissues. PMID:25995658

  17. Heat generation caused by ablation of dental hard tissues with an ultrashort pulse laser (USPL) system.

    PubMed

    Braun, Andreas; Krillke, Raphael Franz; Frentzen, Matthias; Bourauel, Christoph; Stark, Helmut; Schelle, Florian

    2015-02-01

    Heat generation during the removal of dental hard tissues may lead to a temperature increase and cause painful sensations or damage dental tissues. The aim of this study was to assess heat generation in dental hard tissues following laser ablation using an ultrashort pulse laser (USPL) system. A total of 85 specimens of dental hard tissues were used, comprising 45 specimens of human dentine evaluating a thickness of 1, 2, and 3 mm (15 samples each) and 40 specimens of human enamel with a thickness of 1 and 2 mm (20 samples each). Ablation was performed with an Nd:YVO4 laser at 1,064 nm, a pulse duration of 9 ps, and a repetition rate of 500 kHz with an average output power of 6 W. Specimens were irradiated for 0.8 s. Employing a scanner system, rectangular cavities of 1-mm edge length were generated. A temperature sensor was placed at the back of the specimens, recording the temperature during the ablation process. All measurements were made employing a heat-conductive paste without any additional cooling or spray. Heat generation during laser ablation depended on the dental hard tissue (enamel or dentine) and the thickness of the respective tissue (p < 0.05). Highest temperature increase could be observed in the 1-mm thickness group for enamel. Evaluating the 1-mm group for dentine, a significantly lower temperature increase could be measured (p < 0.05) with lowest values in the 3-mm group (p < 0.05). A time delay for temperature increase during the ablation process depending on the material thickness was observed for both hard tissues (p < 0.05). Employing the USPL system to remove dental hard tissues, heat generation has to be considered. Especially during laser ablation next to pulpal tissues, painful sensations and potential thermal injury of pulp tissue might occur. PMID:23666547

  18. A study to evaluate cephalometric hard tissue profile of Tamil population for orthognathic surgery

    PubMed Central

    Nachiappan, S.; Tharanikumar, S.; Chandran, Ajay; Anusudha, P.; Nandini, G. D.; Balasubramaniam, Murali

    2015-01-01

    The primary aim of this study is to compare, the cephalometric hard tissue profile values and analysis between Tamil and Caucasian population. The study also aims to create a better understanding in the facial proportions of Tamil Nadu population and to have better diagnosis and treatment planning for orthognathic surgery for Tamil population in Tamil Nadu. PMID:26538943

  19. Stem cells for tooth engineering.

    PubMed

    Bluteau, G; Luder, H U; De Bari, C; Mitsiadis, T A

    2008-01-01

    Tooth development results from sequential and reciprocal interactions between the oral epithelium and the underlying neural crest-derived mesenchyme. The generation of dental structures and/or entire teeth in the laboratory depends upon the manipulation of stem cells and requires a synergy of all cellular and molecular events that finally lead to the formation of tooth-specific hard tissues, dentin and enamel. Although mesenchymal stem cells from different origins have been extensively studied in their capacity to form dentin in vitro, information is not yet available concerning the use of epithelial stem cells. The odontogenic potential resides in the oral epithelium and thus epithelial stem cells are necessary for both the initiation of tooth formation and enamel matrix production. This review focuses on the different sources of stem cells that have been used for making teeth in vitro and their relative efficiency. Embryonic, post-natal or even adult stem cells were assessed and proved to possess an enormous regenerative potential, but their application in dental practice is still problematic and limited due to various parameters that are not yet under control such as the high risk of rejection, cell behaviour, long tooth eruption period, appropriate crown morphology and suitable colour. Nevertheless, the development of biological approaches for dental reconstruction using stem cells is promising and remains one of the greatest challenges in the dental field for the years to come. PMID:18671204

  20. Influence of water environment on holmium laser ablation performance for hard tissues.

    PubMed

    Lü, Tao; Xiao, Qing; Li, Zhengjia

    2012-05-01

    This study clarifies the ablation differences in air and in water for hard biological tissues, which are irradiated by fiber-guided long-pulsed holmium lasers. High-speed photography is used to record the dynamic characteristics of ablation plumes and vaporization bubbles induced by pulsed holmium lasers. The ablation morphologies and depth of hard tissues are quantitatively measured by optical coherence microscopy. Explosive vaporization effects in water play a positive role in the contact ablation process and are directly responsible for significant ablation enhancement. Furthermore, water layer depth can also contribute to ablation performance. Under the same laser parameters for fiber-tissue contact ablation in air and water, ablation performances are comparable for a single-laser pulse, but for more laser pulses the ablation performances in water are better than those in air. Comprehensive knowledge of ablation differences under various environments is important, especially in medical procedures that are performed in a liquid environment. PMID:22614434

  1. Behavioral characteristics of manual palpation to localize hard nodules in soft tissues.

    PubMed

    Konstantinova, Jelizaveta; Li, Min; Mehra, Gautam; Dasgupta, Prokar; Althoefer, Kaspar; Nanayakkara, Thrishantha

    2014-06-01

    Improving the effectiveness of artificial tactile sensors for soft-tissue examination and tumor localization is a pressing need in robot-assisted minimally invasive surgery. Despite the availability of tactile probes, guidelines for optimal palpation behavior that best exploit soft-tissue properties are not available as yet. Simulations on soft-tissue palpation show that particular stress-velocity patterns during tissue probing lead to constructive dynamic interactions between the probe and the tissue, enhancing the detection and localization of hard nodules. To the best of our knowledge, this is the first attempt to methodically evaluate the hypothesis that specific human palpation behaviors (defined by the fingers' velocity, trajectory, and exerted force) directly influence the diagnosis of soft-tissue organs. Here, we use simulation studies involving human participants to establish open hypotheses on the interaction and influence of relevant behavioral palpation variables, such as finger trajectory, its velocity, and force exerted by fingers on the accuracy of detecting embedded nodules. We validate this hypothesis through finite element analysis and the investigation of palpation strategies used by humans during straight unidirectional examination to detect hard nodules inside silicone phantoms and ex-vivo porcine organs. Thus, we conclude that the palpation strategy plays an important role during soft-tissue examination. Our findings allow us, for the first time, to derive palpation behavior guidelines suitable for the design of controllers of palpation robots. PMID:24845274

  2. Adipose Stem Cells Used to Reconstruct 13 Cases With Cranio-Maxillofacial Hard-Tissue Defects

    PubMed Central

    Numminen, Jura; Wolff, Jan; Thesleff, Tuomo; Miettinen, Aimo; Tuovinen, Veikko J.; Mannerström, Bettina; Patrikoski, Mimmi; Seppänen, Riitta; Miettinen, Susanna; Rautiainen, Markus; Öhman, Juha

    2014-01-01

    Although isolated reports of hard-tissue reconstruction in the cranio-maxillofacial skeleton exist, multipatient case series are lacking. This study aimed to review the experience with 13 consecutive cases of cranio-maxillofacial hard-tissue defects at four anatomically different sites, namely frontal sinus (3 cases), cranial bone (5 cases), mandible (3 cases), and nasal septum (2 cases). Autologous adipose tissue was harvested from the anterior abdominal wall, and adipose-derived stem cells were cultured, expanded, and then seeded onto resorbable scaffold materials for subsequent reimplantation into hard-tissue defects. The defects were reconstructed with either bioactive glass or β-tricalcium phosphate scaffolds seeded with adipose-derived stem cells (ASCs), and in some cases with the addition of recombinant human bone morphogenetic protein-2. Production and use of ASCs were done according to good manufacturing practice guidelines. Follow-up time ranged from 12 to 52 months. Successful integration of the construct to the surrounding skeleton was noted in 10 of the 13 cases. Two cranial defect cases in which nonrigid resorbable containment meshes were used sustained bone resorption to the point that they required the procedure to be redone. One septal perforation case failed outright at 1 year because of the postsurgical resumption of the patient’s uncontrolled nasal picking habit. PMID:24558162

  3. Imaging of cochlear tissue with a grating interferometer and hard X-rays

    SciTech Connect

    Richter, Claus-Peter; Shintani-Smith, Stephanie; Fishman, Andrew; David, Christian; Robinson, Ian; Rau, Christoph

    2010-01-28

    This article addresses an important current development in medical and biological imaging: the possibility of imaging soft tissue at resolutions in the micron range using hard X-rays. Challenging environments, including the cochlea, require the imaging of soft tissue structure surrounded by bone. We demonstrate that cochlear soft tissue structures can be imaged with hard X-ray phase contrast. Furthermore, we show that only a thin slice of the tissue is required to introduce a large phase shift. It is likely that the phase contrast image of the soft tissue structures is sufficient to image the structures even if surrounded by bone. For the present set of experiments, structures with low-absorption contrast have been visualized using in-line phase contrast imaging and a grating interferometer. The experiments have been performed at the Advanced Photon Source at Argonne National Laboratories, a third generation source of synchrotron radiation. The source provides highly coherent X-ray radiation with high-photon flux (>10{sup 12} photons/s) at high-photon energies (5-70 keV). Radiographic and light microscopy images of the gerbil cochlear slice samples were compared. It has been determined that a 20-{micro}m thick tissue slice induces a phase shift between 1/3{pi} and 2/3{pi}.

  4. Adhesion/decalcification mechanisms of acid interactions with human hard tissues.

    PubMed

    Yoshioka, M; Yoshida, Y; Inoue, S; Lambrechts, P; Vanherle, G; Nomura, Y; Okazaki, M; Shintani, H; Van Meerbeek, B

    2002-01-01

    In order to study adhesion/decalcification mechanisms of acid interactions with human hard tissues such as bones and teeth, the chemical interaction of five carboxylic acids (acetic, citric, lactic, maleic, and oxalic) and two inorganic acids (hydrochloric and nitric) with enamel and two synthetic hydroxyapatite (HAp) powders with, respectively, a high and a low crystallinity were analyzed using X-ray photoelectron spectroscopy (XPS), atomic absorption spectrophotometry (AAS), and spectrophotometry (S). X-ray diffraction revealed that the crystallinity of the highly crystallized HAp was considerably higher than that of enamel while the crystallinity of the poorly crystallized HAp was similar to that of dentin and bone. XPS of acid-treated enamel demonstrated for all carboxylic acids ionic bonding to calcium of HAp. AAS and S showed for both HAps that all carboxylic and inorganic acids except oxalic acid extracted Ca significantly more than P, leading to a Ca/P ratio close to that of synthetic HAp (2.16 w/w). Oxalic acid extracted hardly any Ca, but substantially more P, leading to a significantly smaller Ca/P ratio than that of HAp. AAS showed that the calcium salt of oxalic acid hardly could be dissolved, whereas the calcium salts of all the other acids were very soluble in their respective acid solution. These results confirm the adhesion/decalcification concept (AD-concept) previously advanced. Depending on the dissolution rate of the respective calcium salts, acids either adhere to or decalcify apatitic substrates. It is concluded that the AD-concept that originally dictated the interaction of carboxylic acids with human hard tissues can be extended to inorganic acids, such as hydrochloric and nitric acid. Furthermore, HAp crystallinity was found not to affect the adhesion/decalcification behavior of acids when interacting with apatitic substrates, so that the AD-concept can be applied to all human hard tissues with varying HAp crystallinity. PMID:11745537

  5. Hydrodynamic model for ultra-short pulse ablation of hard dental tissue

    SciTech Connect

    London, R.A.; Bailey, D.S.; Young, D.A.; Alley, W.E.; Feit, M.D.; Rubenchik, A.M.; Neev, J.

    1996-02-29

    A computational model for the ablation of tooth enamel by ultra-short laser pulses is presented. The role of simulations using this model in designing and understanding laser drilling systems is discussed. Pulses of duration 300 fsec and intensity greater than 10{sup 12} W/cm{sup 2} are considered. Laser absorption proceeds via multi-photon initiated plasma mechanism. The hydrodynamic response is calculated with a finite difference method, using an equation of state constructed from thermodynamic functions including electronic, ion motion, and chemical binding terms. Results for the ablation efficiency are presented. An analytic model describing the ablation threshold and ablation depth is presented. Thermal coupling to the remaining tissue and long-time thermal conduction are calculated. Simulation results are compared to experimental measurements of the ablation efficiency. Desired improvements in the model are presented.

  6. Hard tissue as a composite material. I - Bounds on the elastic behavior.

    NASA Technical Reports Server (NTRS)

    Katz, J. L.

    1971-01-01

    Recent determination of the elastic moduli of hydroxyapatite by ultrasonic methods permits a re-examination of the Voigt or parallel model of the elastic behavior of bone, as a two phase composite material. It is shown that such a model alone cannot be used to describe the behavior of bone. Correlative data on the elastic moduli of dentin, enamel and various bone samples indicate the existence of a nonlinear dependence of elastic moduli on composition of hard tissue. Several composite models are used to calculate the bounds on the elastic behavior of these tissues. The limitations of these models are described, and experiments to obtain additional critical data are discussed.

  7. Visualization of liquid-assisted hard tissue ablation with a pulsed CO2 laser

    NASA Astrophysics Data System (ADS)

    Li, X. W.; Chen, C. G.; Zhang, X. Z.; Zhan, Z. L.; Xie, S. S.

    2015-01-01

    To investigate the characteristics of liquid-mediated hard tissue ablation induced by a pulsed CO2 laser with a wavelength of 10.6 μm, a high speed camera was used to monitor the interaction between water, tissue and laser irradiation. The results showed that laser irradiation can directly impact on tissue through a vapor channel formed by the leading part of the laser pulse. The ablation debris plays a key role in liquid-assisted laser ablation, having the ability to keep the vapor channel open to extend actuation time. The runoff effect induced by vortex convection liquid flow can remove the tissue that obstructs the effect of the next laser pulse.

  8. Hard tissue formation of STRO-1-selected rat dental pulp stem cells in vivo.

    PubMed

    Yang, Xuechao; Walboomers, X Frank; van den Beucken, Jeroen J J P; Bian, Zhuan; Fan, Mingwen; Jansen, John A

    2009-02-01

    The objective of this study was to examine hard tissue formation of STRO-1-selected rat dental pulp-derived stem cells, seeded into a calcium phosphate ceramic scaffold, and implanted subcutaneously in mice. Previously, STRO-1 selection was used to obtain a mesenchymal stem cell progenitor subpopulation from primary dental pulp-derived stem cells. In the current study, these cells were cultured with three different media: "BMP-plus" medium containing dexamethasone and 100 ng/mL of rhBMP-2, "odontogenic" medium containing dexamethasone, and "control" medium without supplements. The cell-scaffold complexes were cultured in these media for 1, 4, or 8 days before implantation. Histological analysis demonstrated that the cultures with BMP-plus and 4 days of culture gave the highest percentage of hard tissue formation per implant (36 +/- 9% of pore area). Real-time PCR confirmed these results. In conclusion, STRO-1-selected dental pulp stem cells show effective hard tissue formation in vivo, and a short in vitro culture period and addition of BMP-2 can enhance this effect. PMID:18652538

  9. An intramembranous ossification model for the in silico analysis of bone tissue formation in tooth extraction sites.

    PubMed

    Corredor-Gómez, Jennifer Paola; Rueda-Ramírez, Andrés Mauricio; Gamboa-Márquez, Miguel Alejandro; Torres-Rodríguez, Carolina; Cortés-Rodríguez, Carlos Julio

    2016-07-21

    The accurate modeling of biological processes allows us to predict the spatiotemporal behavior of living tissues by computer-aided (in silico) testing, a useful tool for the development of medical strategies, avoiding the expenses and potential ethical implications of in vivo experimentation. A model for bone healing in mouth would be useful for selecting proper surgical techniques in dental procedures. In this paper, the formulation and implementation of a model for Intramembranous Ossification is presented aiming to describe the complex process of bone tissue formation in tooth extraction sites. The model consists in a mathematical description of the mechanisms in which different types of cells interact, synthesize and degrade extracellular matrices under the influence of biochemical factors. Special attention is given to angiogenesis, oxygen-dependent effects and growth factor-induced apoptosis of fibroblasts. Furthermore, considering the depth-dependent vascularization of mandibular bone and its influence on bone healing, a functional description of the cell distribution on the severed periodontal ligament (PDL) is proposed. The developed model was implemented using the finite element method (FEM) and successfully validated by simulating an animal in vivo experiment on dogs reported in the literature. A good fit between model outcome and experimental data was obtained with a mean absolute error of 3.04%. The mathematical framework presented here may represent an important tool for the design of future in vitro and in vivo tests, as well as a precedent for future in silico studies on osseointegration and mechanobiology. PMID:27113783

  10. Use of a compact fiber optic spectrometer for spectral feedback during the laser ablation of dental hard tissues and restorative materials

    NASA Astrophysics Data System (ADS)

    Cheng, Joyce Y.; Fan, Kenneth; Fried, Daniel

    2006-02-01

    One perceived disadvantage of caries removal using lasers is the loss of the tactile feedback associated with the handpiece. However, alternative methods of acoustic and optical feedback become available with the laser that can be exploited to provide information about the chemical composition of the material ablated, the ablation efficiency and rate, the depth of the incision, and the surface and plume temperature during ablation. Such information can be used to increase the selectivity of ablation, avoid peripheral thermal damage and excessive heat deposition in the tooth, and provide a mechanism of robotic automation. The objective of this study was to test the hypothesis that a compact fiberoptic spectrometer could be used to differentiate between the ablation of sound and carious enamel and dentin and between dental hard tissues and composite. Sound and carious tooth surfaces along with composite restorative materials were scanned with λ=0.355, 2.79 and 9.3 μm laser pulses at irradiation intensities ranging from 0.5-100 J/cm2 and spectra were acquired from λ=250-900-nm using a compact fiber-optic spectrometer. Emission spectra varied markedly with the laser wavelength and pulse duration. Optical feedback was not successful in differentiating between sound and carious enamel and dentin even with the addition of various chromophores to carious lesion areas. However, the spectral feedback was successfully used to differentiate between composites and sound enamel and dentin enabling the selective removal of composite from tooth surfaces using a computer controlled λ=9.3-μm pulsed CO II laser and scanning system.

  11. A method for preparing 2- to 50-micron-thick fresh-frozen sections of large samples and undecalcified hard tissues.

    PubMed

    Kawamoto, T; Shimizu, M

    2000-05-01

    This article describes a method for preparing 2- to 50-micron-thick fresh-frozen sections from large samples and completely calcified tissue samples. In order to perform the more routine work involved, a tungsten carbide disposable blade was installed to a heavy-duty sledge cryomicrotome. An entire 10-day-old rat and bone and tooth samples from a 7-month-old rat were rapidly frozen. The frozen samples were attached to the cryomicrotome stage. The cutting surface of the samples was covered with a polyvinylidene chloride film coated with synthetic rubber cement and cut at -25 degrees C. The soft tissues and the hard tissues were satisfactorily preserved and all tissue cells were easily identifiable. Enzymatic activity in the fresh sections was much stronger than that in chemically fixed and/or decalcified sections. The sections permitted histological and histochemical studies without trouble. In addition, the sections can be used for multiple experiments such as immunohistochemistry, in situ hybridization, and electron microprobe X-ray micro-analysis. This method can be used with conventional cryomicrotome equipment. PMID:10883392

  12. OCT monitoring of diffusion of clearing agents within tooth dentin

    NASA Astrophysics Data System (ADS)

    Trunina, N. A.; Lychagov, V. V.; Tuchin, V. V.

    2009-08-01

    Monitoring of agent diffusion within tooth tissues is important in a wide context of tooth therapy (diffusion of medicinal preparations) and cosmetics (chemical whitening agents). We report here the results of optical coherence tomography (OCT) monitoring of diffusion of water and glycerol as clearing agents in samples of human tooth tissue. The diffusion process is analyzed by monitoring the changes in the OCT signal slope and the depth-resolved amplitude of OCT signal from a sample. Slow temporal kinetics of the mean attenuation coefficient was measured to monitor a saturable optical clearing due to the diffusion of the agent. The average permeability coefficient was estimated by dividing the measured thickness of the selected region by the time it took for the agent to diffuse through. The experimental results demonstrate that OCT can be an efficient tool in the study of agent diffusion through hard tissues.

  13. The High Frequency Ultrasonic Diagnostic System for Hard and Soft Tissue Specific Assessments in Dentistry

    NASA Astrophysics Data System (ADS)

    Slak, Bartosz

    The numerical assessment of dental tissues is essential when selecting a relevant treatment protocol in the field of dentistry. This will have significant ramifications on the restoration quality of dental tissues. The aim of the research study presented in this thesis was to validate applicability and obtain non-invasively, quantitative data for hard and soft tissue thickness in dental applications. An ultrasonic system was developed and assembled for the purpose of these experiments. Numerous laboratory trials were conducted to validate system performance against traditional and destructive methods of assessment. Ultrasonic measurements were found to yield similar values to those obtained from invasive methods. Results obtained in these experiments have validated potentials of ultrasound as a supplementary diagnostic tool for dental healthcare.

  14. [Boron in dental hard tissues studied by 11B(p,alpha)8Be nuclear reaction].

    PubMed

    Torrisi, L; Rapisarda, E; Cicero, G

    1989-09-01

    Boron's low atomic number and low concentration make its measurement in hard dental tissues difficult. Using nuclear reaction, the 11B(p,alpha)8Be*, enamel, dentine and radicular cement of 18 dental elements, ten healthy and eight decayed teeth, both permanent and deciduous were studied. The highest Boron concentrations were found in the two most superficial microns of the vestibular enamel in non-decayed incisors, particularly deciduous ones. Premolar and molar teeth showed lower Boron concentrations than frontal ones, decayed teeth revealed hardly any Boron. In confirmation of the prevailing exogenous contribution of this karyostatic trace element, on average, Boron concentrations were 2.5 times as high as dentine and 10 times as high as cement. PMID:2811808

  15. In vitro and in vivo evaluation of orthopedic interface repair using a tissue scaffold with a continuous hard tissue-soft tissue transition

    PubMed Central

    2013-01-01

    Tendon tears produce pain and decrease joint stability; each year, over 1.1 million rotator cuff tendon surgical procedures are performed worldwide. However, surgical success is highly variable, and the inability of the procedure to drive the regeneration of the normal tendon-bone interface has been identified as a key factor in surgical failure. This study focuses on the development, in vitro evaluation, and in vivo assessment of a tissue scaffold derived from bovine cancellous bone with the potential to direct regeneration of a bone-soft tissue interface. The scaffold is a highly porous scaffold with a continuous hard tissue-soft tissue transition that facilitates load transfer across the interface and contains all of the extracellular matrix components of the orthopedic interface. This study demonstrated the in vitro characterization of the mechanical properties and successful in vivo assessment using an ovine model. PMID:23782505

  16. 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.

  17. Biomaterial Selection for Tooth Regeneration

    PubMed Central

    Yuan, Zhenglin; Nie, Hemin; Wang, Shuang; Lee, Chang Hun; Li, Ang; Fu, Susan Y.; Zhou, Hong

    2011-01-01

    Biomaterials are native or synthetic polymers that act as carriers for drug delivery or scaffolds for tissue regeneration. When implanted in vivo, biomaterials should be nontoxic and exert intended functions. For tooth regeneration, biomaterials have primarily served as a scaffold for (1) transplanted stem cells and/or (2) recruitment of endogenous stem cells. This article critically synthesizes our knowledge of biomaterial use in tooth regeneration, including the selection of native and/or synthetic polymers, three-dimensional scaffold fabrication, stem cell transplantation, and stem cell homing. A tooth is a complex biological organ. Tooth loss represents the most common organ failure. Tooth regeneration encompasses not only regrowth of an entire tooth as an organ, but also biological restoration of individual components of the tooth including enamel, dentin, cementum, or dental pulp. Regeneration of tooth root represents perhaps more near-term opportunities than the regeneration of the whole tooth. In the adult, a tooth owes its biological vitality, arguably more, to the root than the crown. Biomaterials are indispensible for the regeneration of tooth root, tooth crown, dental pulp, or an entire tooth. PMID:21699433

  18. Analysis of dental hard tissues exposed to high temperatures for forensic applications: An in vitro study

    PubMed Central

    Shekhawat, Kuldeep Singh; Chauhan, Arunima

    2016-01-01

    Aim: The aim of this study was to observe and record the macroscopic, radiographic, and microscopic findings obtained after subjecting the teeth to high temperatures. Materials and Methods: An in vitro study was conducted to observe macroscopic, radiographic, and microscopic changes in dental hard tissues in 60 unrestored non carious extracted human teeth. The teeth were grouped based on age: Below 30 years, 30–40 years, and above 40 years The teeth from each age group were further divided into five subgroups, and each subgroup was subjected to a particular temperature: 200°C, 400°C, 600°C, 800°C, and 1000°C. [C = Celsius]. Results: Various degrees of changes in relation to temperature were observed macroscopically, radiographically, and microscopically. The histological examination was limited for teeth exposed to 200°C. Conclusion: This investigation was carried out to study the gross changes, radiographic changes and histological changes in dental hard tissues exposed to high temperatures, which is an important part of forensic science. The aforementioned alterations caused by heat may provide useful information about temperature ranges and duration of exposure to high temperatures. PMID:27555725

  19. A novel basalt fiber-reinforced polylactic acid composite for hard tissue repair.

    PubMed

    Chen, Xi; Li, Yan; Gu, Ning

    2010-08-01

    A basalt fiber (BF) was, for the first time, introduced into a poly(l-lactic acid) (PLLA) matrix as innovative reinforcement to fabricate composite materials for hard tissue repair. Firstly, BF/PLLA composites and pure PLLA were produced by the methods of solution blending and freeze drying. The results showed that basalt fibers can be uniformly dispersed in the PLLA matrix and significantly improve the mechanical properties and hydrophilicity of the PLLA matrix. The presence of basalt fibers may retard the polymer degradation rate and neutralize the acid degradation from PLLA. Osteoblasts were cultured in vitro to evaluate the cytocompatibility of the composite. An MTT assay revealed that osteoblasts proliferated well for 7 days and there was little difference found in their viability on both PLLA and BF/PLLA films, which was consistent with the alkaline phosphatase (ALP) activity results. A fluorescent staining observation showed that osteoblasts grew well on the composites. SEM images displayed that osteoblasts tended to grow along the fiber axis. The formation of mineralized nodules was observed on the films by Alizarin red S staining. These results suggest that the presence of basalt fibers does not noticeably affect osteoblastic behavior and the designed composites are osteoblast compatible. It is concluded that basalt fibers, as reinforcing fibers, may have promising applications in hard tissue repair. PMID:20683132

  20. Tooth anatomy

    MedlinePlus

    ... page: //medlineplus.gov/ency/article/002214.htm Tooth anatomy To use the sharing features on this page, ... upper jawbone is called the maxilla. Images Tooth anatomy References Lingen MW. Head and neck. In: Kumar ...

  1. Tooth Disorders

    MedlinePlus

    ... These include eating, speaking and even smiling. But tooth disorders are nothing to smile about. They include problems ... with your teeth. Fortunately, you can prevent many tooth disorders by taking care of your teeth and keeping ...

  2. Vascular imaging with contrast agent in hard and soft tissues using microcomputed-tomography.

    PubMed

    Blery, P; Pilet, P; Bossche, A Vanden-; Thery, A; Guicheux, J; Amouriq, Y; Espitalier, F; Mathieu, N; Weiss, P

    2016-04-01

    Vascularization is essential for many tissues and is a main requisite for various tissue-engineering strategies. Different techniques are used for highlighting vasculature, in vivo and ex vivo, in 2-D or 3-D including histological staining, immunohistochemistry, radiography, angiography, microscopy, computed tomography (CT) or micro-CT, both stand-alone and synchrotron system. Vascularization can be studied with or without a contrast agent. This paper presents the results obtained with the latest Skyscan micro-CT (Skyscan 1272, Bruker, Belgium) following barium sulphate injection replacing the bloodstream in comparison with results obtained with a Skyscan In Vivo 1076. Different hard and soft tissues were perfused with contrast agent and were harvested. Samples were analysed using both forms of micro-CT, and improved results were shown using this new micro-CT. This study highlights the vasculature using micro-CT methods. The results obtained with the Skyscan 1272 are clearly defined compared to results obtained with Skyscan 1076. In particular, this instrument highlights the high number of small vessels, which were not seen before at lower resolution. This new micro-CT opens broader possibilities in detection and characterization of the 3-D vascular tree to assess vascular tissue engineering strategies. PMID:27002484

  3. Tooth anatomy

    MedlinePlus

    The part of the tooth you can see is called the crown. The outer surface of the crown is made of enamel. Just beneath the ... The gum surrounds the base (root) of the tooth. The root of the tooth extends down into ...

  4. [Tooth erosion - a multidisciplinary approach].

    PubMed

    Strużycka, Izabela; Rusyan, Ewa; Bogusławska-Kapała, Agnieszka

    2016-02-01

    During the last decades, an increasingly greater interest in dental erosion has been observed in clinical dental practice, in dental public health and in dental research because prevalence of erosive tooth wear is still increasing especially in young age group of population. Erosive tooth wear is a multifactorial etiology process characterized by progressive loss of hard dental tissue. It is defined as the exogenous and/or endogenous acids dissolution of the dental tissue, without bacterial involvement. In the development of dental erosive wear, interactions are required which include chemical, biological, behavioral, diet, time, socioeconomic, knowledge, education, and general health factors. Examples of risk groups could be patients with eating disorders, like anorexia nervosa or bulimia nervosa, gastroesophageal reflux disease, chronic alcohol abuse or dependence. Special nutrition habits groups with high consumption of soft or sport drinks, special diets like vegetarian, vegan or raw food diet, the regular intake of drugs, medications and food supplements can also increase the risk for dental erosion. Comprehensive knowledge of the different risk and protective factors is a perquisite for initiating adequate preventive measures. PMID:27000809

  5. A three-dimensional analysis of soft and hard tissue changes after a mandibular setback surgery.

    PubMed

    Kim, Nam-Kug; Lee, Cheol; Kang, Suk-Ho; Park, Jae-Woo; Kim, Myung-Jin; Chang, Young-Il

    2006-09-01

    This paper is concerned with a three-dimensional (3D) analysis on soft and hard tissue changes after mandibular setback surgery. For comparing with previous two-dimensional (2D) cephalometric data, we proposed a three-dimensional registration and analysis method based on the cephalometric knowledge. The 3D changes of bone, soft tissue and the ratio of soft tissue to bony movement were investigated in eight skeletal class III mandibular prognathism patients. CT scans of each patient were taken at pre- and post-operative states. Each scan was registered to a universal 3D coordinate system defined by cephalometric landmarks. A grid, parallel to the coronal plane, was also designed for the comparison of the changes. The bone and soft tissue was intersected by the projected line from each point on the grid. The coordinate values of intersected point were measured and compared between the pre- and post-operative models. In addition, the reproducibility of the universal coordinate system and the grid was evaluated. The facial surface changes after setback surgery occurred not only in the mandible but also in the mouth corner region. The soft tissue changes of the mandible were measured relatively by the proportional ratios to the bone changes. The ratios at the mid-sagittal plane were 77-102% (p<0.05). The ratios at all other sagittal planes had similar patterns to the mid-sagittal plane with decreased values. All the results conformed to the previous 2D based clinical knowledge and instinct of orthodontists. It is expected that the proposed approach would be applicable to other oral and maxillofacial surgeries as well as plastic surgeries. PMID:16919839

  6. Evaluation of 3D nano-macro porous bioactive glass scaffold for hard tissue engineering.

    PubMed

    Wang, S; Falk, M M; Rashad, A; Saad, M M; Marques, A C; Almeida, R M; Marei, M K; Jain, H

    2011-05-01

    Recently, nano-macro dual-porous, three-dimensional (3D) glass structures were developed for use as bioscaffolds for hard tissue regeneration, but there have been concerns regarding the interconnectivity and homogeneity of nanopores in the scaffolds, as well as the cytotoxicity of the environment deep inside due to limited fluid access. Therefore, mercury porosimetry, nitrogen absorption, and TEM have been used to characterize nanopore network of the scaffolds. In parallel, viability of MG 63 human osteosarcoma cells seeded on scaffold surface was investigated by fluorescence, confocal and electron microscopy methods. The results show that cells attach, migrate and penetrate inside the glass scaffold with high proliferation and viability rate. Additionally, scaffolds were implanted under the skin of a male New Zealand rabbit for in vivo animal test. Initial observations show the formation of new tissue with blood vessels and collagen fibers deep inside the implanted scaffolds with no obvious inflammatory reaction. Thus, the new nano-macro dual-porous glass structure could be a promising bioscaffold for use in regenerative medicine and tissue engineering for bone regeneration. PMID:21445655

  7. Functional micro-imaging of soft and hard tissue using synchrotron light

    NASA Astrophysics Data System (ADS)

    Thurner, Philipp J.; Wyss, Peter; Voide, Romain; Stauber, Martin; Muller, Bert; Stampanoni, Marco; Hubbell, Jeffrey A.; Muller, Ralph; Sennhauser, Urs

    2004-10-01

    In current biological and biomedical research, quantitative endpoints have become an important factor of success. Classically, such endpoints were investigated with 2D imaging, which is usually destructive and the 3D character of tissue gets lost. 3D imaging has gained in importance as a tool for both, qualitative and quantitative assessment of biological systems. In this context synchrotron radiation based tomography has become a very effective tool for opaque 3D tissue systems. Cell cultures and adherent scaffolds are visualized in 3D in a hydrated environment, even uncovering the shape of individual cells. Advanced morphometry allows to characterize the differences between the cell cultures of two distinct phenotypes. Moreover, a new device is presented enabling the 3D investigation of trabecular bone under mechanical load in a time-lapsed fashion. Using the highly brilliant X-rays from a synchrotron radiation source, bone microcracks and an indication for un-cracked ligament bridging are uncovered. 3D microcrack analysis proves that the classification of microcracks from 2D images is ambiguous. Fatigued bone was found to fail in burst-like fashion, whereas non-fatigued bone exhibited a distinct failure band. Additionally, a higher increase in microcrack volume was detected in fatigued in comparison to non-fatigued bone. The developed technologies prove to be very effective tools for advanced 3D imaging of both hard and soft tissue.

  8. Degradation and drug release of phosphate glass/polycaprolactone biological composites for hard-tissue regeneration.

    PubMed

    Kim, Hae-Won; Lee, Eun-Jung; Jun, In-Kook; Kim, Hyoun-Ee; Knowles, Jonathan C

    2005-10-01

    Phosphate-based glass (P-glass) and poly(epsilon-caprolactone) (PCL) composites were fabricated in a sheet form by solvent extraction and thermal pressing methods, and the antibiotic drug Vancomycin was loaded within the composites for use as a hard-tissue regenerative. The degradation and drug-release rate of the composites in vitro were tailored by modifying the glass composition: 0.45 P(2)O(5)-x CaO-(0.55-x)Na(2)O, where x=0.2, 0.3, 0.4, and 0.5. Compared to pure PCL, all the P-glass/PCL composites degraded to a higher degree, and the composite with lower-CaO glass showed a higher material loss. This was attributed mainly to the dissolution of the glass component. The glass dissolution also increased the degradation of PCL component in the composites. The Vancomycin release from the composites was strongly dependent on the glass composition. Drug release in pure PCL was initially abrupt and flattened out over a prolonged period. However, glass/PCL composites (particularly in the glass containing higher-CaO) exhibited a reduced initial burst and a higher release rate later. Preliminary cell tests on the extracts from the glass/PCL composites showed favorable cell proliferation, but the level was dependent on the ionic concentration of the extracts. The cell proliferation on the diluted extracts from the composite with higher-CaO glass was significantly higher than that on the blank culture dish. These observations confirmed that the P-glass/PCL composites are potentially applicable for use as hard-tissue regeneration and wound-healing materials because of their controlled degradation and drug-release profile as well as enhanced cell viability. PMID:16001393

  9. Evaluation of DNA typing as a positive identification method for soft and hard tissues immersed in strong acids.

    PubMed

    Robino, C; Pazzi, M; Di Vella, G; Martinelli, D; Mazzola, L; Ricci, U; Testi, R; Vincenti, M

    2015-11-01

    Identification of human remains can be hindered by several factors (e.g., traumatic mutilation, carbonization or decomposition). Moreover, in some criminal cases, offenders may purposely adopt various expedients to thwart the victim's identification, including the dissolution of body tissues by the use of corrosive reagents, as repeatedly reported in the past for Mafia-related murders. By means of an animal model, namely porcine samples, we evaluated standard DNA typing as a method for identifying soft (muscle) and hard (bone and teeth) tissues immersed in strong acids (hydrochloric, nitric and sulfuric acid) or in mixtures of acids (aqua regia). Samples were tested at different time intervals, ranging between 2 and 6h (soft tissues) and 2-28 days (hard tissues). It was shown that, in every type of acid, complete degradation of the DNA extracted from soft tissues preceded tissue dissolution and could be observed within 4h of immersion. Conversely, high molecular weight DNA amenable to STR analysis could be isolated from hard tissues as long as cortical bone fragments were still present (28 days for sulfuric acid, 7 days for nitric acid, 2 days for hydrochloric acid and aqua regia), or the integrity of the dental pulp chamber was preserved (7 days, in sulfuric acid only). The results indicate that DNA profiling of acid-treated body parts (in particular, cortical bone) is still feasible at advanced stages of corrosion, even when the morphological methods used in forensic anthropology and odontology can no longer be applied for identification purposes. PMID:26195111

  10. 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

  11. Combined effects of estrogen deficiency and cadmium exposure on calcified hard tissues: Animal model relating to itai-itai disease in postmenopausal women

    PubMed Central

    KAKEI, Mitsuo; SAKAE, Toshiro; YOSHIKAWA, Masayoshi

    2013-01-01

    Using ovariectomized rats as a model of postmenopausal women, we studied the effects of estrogen (Es) deficiency and in combination with cadmium (Cd) exposure on the calcified hard tissues related to the development of itai-itai disease. Es deficiency suppressed the synthesis of carbonic anhydrase required for the crystal nucleation process, causing the crystal structure defects in the tooth enamel. Regarding the combined effects of Es deficiency and Cd exposure on the bone, in which rats were given drinking water containing Cd ions, soft X-ray radiography revealed a development of labyrinthine pattern in the calvaria, and micro-computed tomography demonstrated the declining trabecular architecture of the tibia, suggesting Cd–induced osteoporotic change. Further, electron microscopy showed the increase of amorphous minerals in the calvaria. In conclusion, the combined effects of Es deficiency and Cd exposure can be responsible for accelerating the declining bone strength together with the crystal structure defects resulting in the preferential occurrence of itai-itai disease in postmenopausal women. PMID:23883612

  12. Combined Soft and Hard Tissue Peri-Implant Plastic Surgery Techniques to Enhance Implant Rehabilitation: A Case Report

    PubMed Central

    Baltacıoğlu, Esra; Korkmaz, Fatih Mehmet; Bağış, Nilsun; Aydın, Güven; Yuva, Pınar; Korkmaz, Yavuz Tolga; Bağış, Bora

    2014-01-01

    This case report presents an implant-aided prosthetic treatment in which peri-implant plastic surgery techniques were applied in combination to satisfactorily attain functional aesthetic expectations. Peri-implant plastic surgery enables the successful reconstruction and restoration of the balance between soft and hard tissues and allows the option of implant-aided fixed prosthetic rehabilitation. PMID:25489351

  13. Assessment of Tooth Proportions in an Aesthetically Acceptable Smile

    PubMed Central

    Reddy, Munish; Raghav, Pradeep; Jain, Shalu; Anjum, Arbab; Misra, Vaibhav; Suri, Ragini

    2015-01-01

    Introduction: Aesthetic facial animation is mostly reported to be due to a close relationship between soft and hard tissue i.e. dynamic smile with appropriate tooth proportions. But variations in tooth size have been seen among various ethnic populations globally. Aim: To evaluate the size and morphology of maxillary anterior teeth, the tooth with maximum variation both mesiodistally and cervicoincisally. Also, the tooth to tooth ratio in percentage of the mean tooth sizes in both genders in patients with aesthetically acceptable smile decided by a panel in North Indian population. Materials and Methods: A total of 100 subjects (50 males and 50 females) were taken and a video clip of their dynamic smile was captured .The smiles were analyzed by a panel and the tooth proportions of the selected attractive smiles were evaluated in both males and females separately. Statistical analysis: Data obtained was subjected to statistical analysis using Microsoft Excel 2007 software; test used was Unpaired t-test and also Mean ± S.D., Variance, Ratio of W/L and its ranges were calculated. Significance is assessed at 5% level of significance. Results: The mesiodistal width and cervicoincisal length of maxillary central incisor was greater compared to lateral incisor and canine in both males and females. There was a statistically significant difference between the width/length ratio of maxillary anterior teeth between males and females.Canine and Lateral incisor showed maximum variation mesio-distally and cervico-incisally. Conclusion: A smile is more pleasing if the visible teeth are in proper morphological proportions. Thus, it relates that teeth play a vital role in increasing the attractiveness of a smile. The mean coronal width/length ratio displayed a more square like tooth form for both males and females. PMID:26023632

  14. Er:YAG laser micro-preparation of hard dental tissue

    NASA Astrophysics Data System (ADS)

    Dostálová, Tat'jana; Jelínková, Helena; Nemec, Michal; Koranda, Petr; Miyagi, Mitsunobu; Iwai, Katsumasa; Shi, Yi-Wei; Matsuura, Yuji

    2007-02-01

    Free running and Q-switch infrared Er:YAG laser radiations were compared in the case of hard tissue preparation. The interaction energy of 40 mJ in pulse 200 us long yielding to the interaction intensity 62 kW/cm2, and the energy of 20 mJ in 100 ns long pulse yielding to the interaction intensity 62 MW/cm2 was used for the case of free running, and Q-switch regime, respectively. For the radiation delivery, waveguide transfer system was used. It consisted of input lens (40 mm focal length), a cyclic olefin polymer coated silver hollow glass waveguide (700/850 um diameter), and output lens (55 um focal length). For the interaction experiment the samples of the extracted human teeth cut into longitudinal sections and polished were used. The thickness of the prepared samples ranged from 5 to 7 mm. The methods were compared from the point of prepared cavity shape (SEM), inner surface, and possibility of selective removal of carries. The composite filling material was used to reconstruct the cavities.

  15. Bone cement with a modified polyphosphate network structure stimulates hard tissue regeneration.

    PubMed

    Lee, Byung-Hyun; Hong, Min-Ho; Kim, Min-Chul; Kwon, Jae-Sung; Ko, Yeong-Mu; Choi, Heon-Jin; Lee, Yong-Keun

    2016-09-01

    In this study, a calcium polyphosphate cement (CpPC) consisting of basic components was investigated to assess its potential for hard tissue regeneration. The added basic components for improving the structural stability, which controlled the setting time, where the setting reaction resulted in the formation of amorphous structure with a re-constructed polyphosphate. Moreover, the characteristics were controlled by the composition, which determined the polyphosphate structure. CpPC exhibited outstanding dissolution rate compared with the common biodegradable cement, brushite cement (2.5 times). Despite high amounts of dissolution products, no significant cytotoxicity ensued. Induction of calcification in MG-63 cells treated with CpPC, the level of calcification increased with increasing CpPC dissolution rate. Induced calcification was observed also in CpPC-treated ST2 cells, in contrast with MG-63 and ST2 treated with brushite cement, for which no calcification was observed. In vivo tests using a rat calvarial defect model showed that resorbed CpPC resulted in favorable host responses and promoted bone formation. Additionally, there was a significant increase in defect closure, and new bone formation progressed from CpPC mid-sites as well as defect margins. From these results, CpPC exhibits significant potential as biodegradable bone substitute for bone regeneration. PMID:27511981

  16. A hard tissue cephalometric comparative study between hand tracing and computerized tracing

    PubMed Central

    Prabhakar, Ramachandra; Rajakumar, P.; Karthikeyan, M. K.; Saravanan, R.; Vikram, N. Raj; Reddy, Adarsh

    2014-01-01

    Aims: To analyze and compare the angular and linear hard tissue cephalometric measurements using hand-tracing and computerized tracings with Nemoceph and Dolphin software systems. Subjects and Methods: A total of 30 cephalograms were randomly chosen for study with the following criteria, cephalograms of patients with good contrast, no distortion, and minimal radiographic artifacts were considered using the digital method (Kodak 8000 C) with 12 angular and nine linear parameters selected for the study. Comparisons were determined by post-hoc test using Tukey HSD method. The N-Par tests were performed using Kruskal-Walli's method. Statistical Analysis Used: ANOVA and post-hoc. Results: The results of this study show that there is no significant difference in the angular and linear measurements recorded. The P values were significant at 0.05 levels for two parameters, Co-A and Co-Gn with the hand-tracing method. This was significant in ANOVA and post-hoc test by Tukey HSD method. Conclusions: This study of comparison provides support for transition from digital hand to computerized tracing methodology. In fact, digital computerized tracings were easier and less time consuming, with the same reliability irrespective of each method of tracing. PMID:25210347

  17. Implant Site Development for Enhancing Esthetics of Soft and Hard Tissue and Simplification of Implant Surgery Using a Forced Eruption.

    PubMed

    Joo, Ji-Young; Son, Sieun; Lee, Ju-Youn

    2016-01-01

    The keys to successful esthetic implant therapy in the anterior region are natural-looking implant restorations and an adequate alveolar ridge volume. Destruction of periodontal tissue resulting from periodontal and/or endodontic inflammation causes esthetic problems. Forced eruption is a valuable adjunct to augmenting the soft and hard tissue where the alveolar ridge is insufficient for esthetics. In this article, forced eruption was adopted for implant site development prior to implant placement and the periodontal tissue was augmented vertically using this technique. This technique simplified the surgical implant procedure without a need for advanced augmentation. PMID:27333017

  18. Estimation of calcified tissues hardness via calcium and magnesium ionic to atomic line intensity ratio in laser induced breakdown spectra

    NASA Astrophysics Data System (ADS)

    Abdel-Salam, Z. A.; Galmed, A. H.; Tognoni, E.; Harith, M. A.

    2007-12-01

    Calcified tissues representing three different matrices, namely enamel of human teeth, shells and eggshell, have been studied via Laser Induced Breakdown Spectroscopy (LIBS) technique. The experimental CaII/CaI and MgII/MgI ratios have been measured, in view of the expected correlation between the extent of ionization caused by the laser induced shock wave (SW) and the hardness of the target. The ratio CaII/CaI between the ionic calcium line at 373.69 nm and the neutral line at 428.9 nm is obtained for enamel, shells and eggshell spectra, as well as the ratio MgII/MgI between the ionic magnesium line at 280.26 nm and the neutral line at 285.22 nm. The results show that such spectral lines intensities ratio differs for different matrices and is indeed related to the target materials hardness. It is also found that the MgII/MgI ratio is preferable as an indicator of hardness since these lines are less affected by self absorption. The SW front speed has been measured in the three cases and the obtained values confirm the proportionality to the target hardness. The results here obtained suggest the feasibility of the quantitative estimation of hardness for any other calcified tissues.

  19. Design and synthesis of polyphosphazenes: Hard tissue scaffolding biomaterials and physically crosslinked elastomers

    NASA Astrophysics Data System (ADS)

    Modzelewski, Tomasz

    The work in this thesis is divided into two main parts. The first part examines the synthesis and characterization of polyphosphazenes as potential scaffolding materials usable for hard tissue repair. The goal of this work was to design polymers containing acidic functional groups in an attempt to encourage the deposition of calcium hydroxyapatite when the polymer is exposed to simulated body fluids. The second part examines the development of a new polymeric architecture which generates elastomeric properties without the use of traditional covalent or physical crosslinks. The goal was to examine the effects of this new architecture on the physical and mechanical properties of the final polymers. Chapter 1 provides a general background for the two main focus areas mentioned above. More specifically: a brief explanation is provided of the necessary physical and chemical properties of a suitable hard tissue engineering scaffolding substrate, and the basis of those requirements; together with an examination of the traditional ways in which elastomeric properties are introduced into a polymeric sample. Chapter 2 details the design and synthesis of polyphosphazenes bearing phosphonic acid and phosphoester side groups using two different routes. The first route utilized a linker unit which was functionalized with phosphoesters prior to its attachment to the polyphosphazene backbone, while the second route involved attachment of the same linking group to the polyphosphazene backbone before the introduction of the phosphoester moieties. In both cases, the samples were treated with iodotrimethylsilane to cleave the ester bonds and afford the parent phosphonic acid. Both routes proved successful. However, varying difficulties were encountered for each route. In Chapter 3 we examine the ability of the phosphonic acid functionalized polyphosphazenes described in Chapter 2 to mineralize calcium hydroxyapatite when exposed to simulated body fluid, which has the same ion

  20. 3D imaging of dental hard tissues with Fourier domain optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Chen, Yueli L.; Yang, Yi; Ma, Jing; Yan, Jun; Shou, Yuanxin; Wang, Tianheng; Ramesh, Aruna; Zhao, Jing; Zhu, Quing

    2011-03-01

    A fiber optical coherence tomography (OCT) probe is used for three dimensional dental imaging. The probe has a lightweight miniaturized design with a size of a pen to facilitate clinic in vivo diagnostics. The probe is interfaced with a swept-source / Fourier domain optical coherence tomography at 20K axial scanning rate. The tooth samples were scanned from occlusal, buccal, lingual, mesial, and distal orientations. Three dimensional imaging covers tooth surface area up to 10 mm x 10 mm with a depth about 5 mm, where a majority of caries affection occurs. OCT image provides better resolution and contrast compared to gold standard dental radiography (X-ray). In particular, the technology is well suited for occlusal caries detection. This is complementary to X-ray as occlusal caries affection is difficult to be detected due to the X-ray projectile scan geometry. The 3D topology of occlusal surface as well as the dentin-enamel junction (DEJ) surface inside the tooth can be visualized. The lesion area appears with much stronger back scattering signal intensity.

  1. Tooth extraction

    MedlinePlus

    ... hole where the tooth was, causing bleeding and pain. This is called dry socket. To care for your mouth: Begin gently brushing and flossing your other teeth the day after your surgery. Avoid the area near the open ...

  2. Tooth Problems

    MedlinePlus

    ... to determine if you need to see your dentist right away. SYMPTOMS DIAGNOSIS SELF-CARE Begin Here ... You have TOOTH LOSS. DENTAL EMERGENCY See your dentist or go to the emergency room right away. ...

  3. Investigation into the interaction of a XeCl excimer laser with hard tissue

    NASA Astrophysics Data System (ADS)

    Murray, Andrea K.; Dickinson, Mark R.

    2000-06-01

    An investigation into the interaction of a fiber deliverable, long pulse, xenon chloride (308 nm) excimer laser with hard biotissue has been carried out. The laser produces pulses of 200+ ns as opposed to around 10 - 20 ns for most of the previously reported data. The threshold of ablation and the maximum ablation depth (AD) in human molar dentine were found to be 0.30 +/- 0.05 J/cm2 and 1.57 +/- 0.04 micrometer/pulse respectively. The threshold for enamel was found to be above the achievable fluence with the available optics. The ablation process was investigated as a function of fluence (approximately 0.1 - 6 J/cm2), pulse repetition rate (PRR) (5 - 25 Hz) and number of pulses (500 - 4000). Each variable was altered independently of the other two. At a constant number of pulses, ablation depth per pulse was found to increase linearly as a function of fluence, up to a saturation fluence of approximately 4 J/cm2. Variation of the PRR alone was found to affect both the ablation threshold and the AD. For constant fluence and PRR, AD decreases non- linearly with an increasing number of pulses. This could be because at high pulse numbers the craters are deep, the walls of the crater absorb more energy and as it is increasingly difficult for the debris to escape, shielding of the tissue occurs. Shielding may also be due to absorption in a luminescent plume. At high fluence and PRR, sharp holes were formed in the dentine although charring was sometimes found around the edges. High PRR also induced considerable mechanical damage.

  4. Immediate total tooth replacement.

    PubMed

    Garber, D A; Salama, M A; Salama, H

    2001-03-01

    Successful implant placement at the time of extraction has been documented. Implant placement at the time of extraction was initially performed as a two-stage procedure often with barrier membranes and sophisticated second-stage surgical uncoverings. The authors describe the next generation of this technique, including atraumatic tooth removal with simultaneous root form, implant placement, and temporization at one appointment. This technique of "Immediate Total Tooth Replacement" allows for the maintenance of the bony housing and soft-tissue form that existed before extraction, while at the same time establishing a root form anchor in the bone for an esthetic restoration. PMID:11913258

  5. Monte Carlo modeling of human tooth optical coherence tomography imaging

    NASA Astrophysics Data System (ADS)

    Shi, Boya; Meng, Zhuo; Wang, Longzhi; Liu, Tiegen

    2013-07-01

    We present a Monte Carlo model for optical coherence tomography (OCT) imaging of human tooth. The model is implemented by combining the simulation of a Gaussian beam with simulation for photon propagation in a two-layer human tooth model with non-parallel surfaces through a Monte Carlo method. The geometry and the optical parameters of the human tooth model are chosen on the basis of the experimental OCT images. The results show that the simulated OCT images are qualitatively consistent with the experimental ones. Using the model, we demonstrate the following: firstly, two types of photons contribute to the information of morphological features and noise in the OCT image of a human tooth, respectively. Secondly, the critical imaging depth of the tooth model is obtained, and it is found to decrease significantly with increasing mineral loss, simulated as different enamel scattering coefficients. Finally, the best focus position is located below and close to the dental surface by analysis of the effect of focus positions on the OCT signal and critical imaging depth. We anticipate that this modeling will become a powerful and accurate tool for a preliminary numerical study of the OCT technique on diseases of dental hard tissue in human teeth.

  6. Methods for studying tooth root cementum by light microscopy.

    PubMed

    Foster, Brian L

    2012-09-01

    The tooth root cementum is a thin, mineralized tissue covering the root dentin that is present primarily as acellular cementum on the cervical root and cellular cementum covering the apical root. While cementum shares many properties in common with bone and dentin, it is a unique mineralized tissue and acellular cementum is critical for attachment of the tooth to the surrounding periodontal ligament (PDL). Resources for methodologies for hard tissues often overlook cementum and approaches that may be of value for studying this tissue. To address this issue, this report offers detailed methodology, as well as comparisons of several histological and immunohistochemical stains available for imaging the cementum-PDL complex by light microscopy. Notably, the infrequently used Alcian blue stain with nuclear fast red counterstain provided utility in imaging cementum in mouse, porcine and human teeth. While no truly unique extracellular matrix markers have been identified to differentiate cementum from the other hard tissues, immunohistochemistry for detection of bone sialoprotein (BSP), osteopontin (OPN), and dentin matrix protein 1 (DMP1) is a reliable approach for studying both acellular and cellular cementum and providing insight into developmental biology of these tissues. Histological and immunohistochemical approaches provide insight on developmental biology of cementum. PMID:22996273

  7. Microanatomy of Passerine hard-cornified tissues: beak and claw structure of the Black-capped Chickadee (Poecile atricapillus)

    USGS Publications Warehouse

    Van Hemert, Caroline R.; Handel, Colleen M.; Blake, J.; Swor, Rhonda; O'Hara, Todd M.

    2012-01-01

    The microanatomy of healthy beaks and claws in passerine birds has not been well described in the literature, despite the importance of these structures in avian life. Histological processing of hard-cornified tissues is notoriously challenging and only a few reports on effective techniques have been published. An emerging epizootic of beak deformities among wild birds in Alaska and the Pacific Northwest region of North America recently highlighted the need for additional baseline information about avian hard-cornified structures. In this study, we examine the beak and claw of the Black-capped Chickadee (Poecile atricapillus), a common North American passerine that is affected by what has been described as “avian keratin disorder.” We use light and scanning electron microscopy and high-magnification radiography to document the healthy microanatomy of these tissues and identify features of functional importance. We also describe detailed methods for histological processing of avian hard-cornified structures and discuss the utility of special stains. Results from this study will assist in future research on the functional anatomy and pathology of hard-cornified structures and will provide a necessary reference for ongoing investigations of avian keratin disorder in Black-capped Chickadees and other wild passerine species.

  8. Microanatomy of passerine hard-cornified tissues: Beak and claw structure of the black-capped chickadee (Poecile atricapillus)

    USGS Publications Warehouse

    Van Hemert, C.; Handel, C.M.; Blake, J.E.; Swor, R.M.; O'Hara, T. M.

    2012-01-01

    The microanatomy of healthy beaks and claws in passerine birds has not been well described in the literature, despite the importance of these structures in avian life. Histological processing of hard-cornified tissues is notoriously challenging and only a few reports on effective techniques have been published. An emerging epizootic of beak deformities among wild birds in Alaska and the Pacific Northwest region of North America recently highlighted the need for additional baseline information about avian hard-cornified structures. In this study, we examine the beak and claw of the Black-capped Chickadee (Poecile atricapillus), a common North American passerine that is affected by what has been described as "avian keratin disorder." We use light and scanning electron microscopy and high-magnification radiography to document the healthy microanatomy of these tissues and identify features of functional importance. We also describe detailed methods for histological processing of avian hard-cornified structures and discuss the utility of special stains. Results from this study will assist in future research on the functional anatomy and pathology of hard-cornified structures and will provide a necessary reference for ongoing investigations of avian keratin disorder in Black-capped Chickadees and other wild passerine species. ?? 2011 Wiley Periodicals, Inc.

  9. β-Type Zr-Nb-Ti biomedical materials with high plasticity and low modulus for hard tissue replacements.

    PubMed

    Nie, Li; Zhan, Yongzhong; Hu, Tong; Chen, Xiaoxian; Wang, Chenghui

    2014-01-01

    In order to develop new biomedical materials for hard tissue replacements, Zr-20Nb-xTi (x=0, 3, 7, 11 and 15) alloys with required properties were designed and prepared by using the vacuum arc melting method for the first time. Phase analysis and microstructural observation showed that all the as cast samples consisted of equiaxed β-Zr phase. The mechanical properties and fracture behaviors of the Zr-20Nb-xTi alloys have been analyzed. It is found that these alloys exhibit high plasticity, moderate compressive strength (1044-1325MPa) and yield stress (854-1080MPa), high elastic energy (12-20MJ/m(3)) and low Young's modulus (28-31GPa). This good combination of mechanical properties makes them potential biomedical materials for hard tissue replacement. PMID:24036526

  10. New Perspectives on Tooth Wear

    PubMed Central

    Lucas, Peter W.; Omar, Ridwaan

    2012-01-01

    Some of the efforts that have been made to document tooth wear are reviewed here with an emphasis on nonhuman mammals, literature with which dentists may not be very familiar. We project a change in research strategy from the description of wear at various scales of measurement towards investigation of the mechanical mechanisms that actually create the texture of a worn surface. These studies should reveal exactly how tooth tissue is lost and what aspects of the structure of dental tissues affect this. The most important aspects of the interaction between the tooth surface and wear particles would appear to be particle size, particle shape, their mechanical properties with respect to those of tooth tissues, and the influence of saliva. PMID:22536239

  11. Tooth patterning and evolution.

    PubMed

    Salazar-Ciudad, Isaac

    2012-12-01

    Teeth are a good system for studying development and evolution. Tooth development is largely independent of the rest of the body and teeth can be grown in culture to attain almost normal morphology. Their development is not affected by the patterns of movement or sensorial perception in the embryo. Teeth are hard and easily preserved. Thus, there is plenty of easily accessible information about the patterns of morphological variation occurring between and within species. This review summarises recent work and describes how tooth development can be understood as the coupling between a reaction-diffusion system and differential growth produced by diffusible growth factors: which growth factors are involved, how they affect each other's expression and how they affect the spatial patterns of proliferation that lead to final morphology. There are some aspects of tooth development, however, that do not conform to some common assumptions in many reaction-diffusion models. Those are discussed here since they provide clues about how reaction-diffusion systems may work in actual developmental systems. Mathematical models implementing what we know about tooth development are discussed. PMID:23266218

  12. Tooth - abnormal shape

    MedlinePlus

    Hutchinson incisors; Abnormal tooth shape; Peg teeth; Mulberry teeth; Conical teeth ... from many different conditions. Specific diseases can affect tooth shape, tooth color, time of appearance, or absence ...

  13. Tooth - abnormal shape

    MedlinePlus

    Hutchinson incisors; Abnormal tooth shape; Peg teeth; Mulberry teeth; Conical teeth ... The appearance of normal teeth varies, especially the molars. ... conditions. Specific diseases can affect tooth shape, tooth ...

  14. Effects of Antibiotics on Bone and Soft-Tissue Healing Following Immediate Single-Tooth Implant Placement Into Sites With Apical Pathology.

    PubMed

    Hosseini, Bashir; Byrd, Warren C; Preisser, John S; Khan, Asma; Duggan, Derek; Bencharit, Sompop

    2015-10-01

    Overprescription of antibiotics can cause bacterial resistance problems, leading to life-threatening illnesses and public health crises. Clinicians often believe antibiotics can prevent dental implant failure and postoperative complications. In conjunction with implant surgery, antibiotics are therefore routinely prescribed for all cases. In this double-blind, randomized controlled trial, the effects of antibiotics on the clinical outcomes of immediate implant placement upon replacing a tooth with an apical pathology were examined to compare antibiotics (n = 10) and placebo (n = 10). In each subject, a tooth with a chronic apical lesion was extracted, thoroughly curetted, irrigated, and replaced with single implant with a screw-retained custom provisional abutment/crown. Postoperative pain/discomfort was measured at 1- and 4-week postsurgical follow-up visits using visual analog scales. Facial alveolar bone and soft-tissue changes were measured using pre- and postoperative cone-beam computerized tomography and impressions. We found survival rates of 100% (antibiotics) and 78% (control). However, there was no statistical difference in means for any clinical outcome (t tests with Bonferroni adjustment for multiple testing), except for midfacial soft-tissue changes: 0.43 mm (SD, 0.76) in the antibiotics group and 1.70 mm (SD, 1.06) in the placebo group (t15 = -2.89, P = .011). The average change of the midfacial alveolar plate was 0.62 mm (SD, 0.46) and 1.34 mm (SD, 0.91) for the antibiotic and placebo groups, respectively, which did not significantly differ statistically. No significant correlation (Spearman correlation) existed between the changes in facial alveolar bone and the facial gingival margin. Antibiotics appear to have little effect on immediate implant treatment outcomes. PMID:25076118

  15. Formation of a hard tissue barrier after experimental pulp capping or partial pulpotomy in humans: an updated systematic review.

    PubMed

    Fransson, H; Wolf, E; Petersson, K

    2016-06-01

    The aim was to update a systematic review of pulp capping and partial pulpotomy by Olsson et al. (2006), by evaluating new evidence on formation of a hard tissue barrier after pulp capping and partial pulpotomy of experimental exposures in humans. PubMed (01-01-2005 to 01-03-2014) and CENTRAL were searched using specific keywords. Hand searches were made and the level of evidence for each included article was evaluated by the authors. The evidence of the conclusions was graded as strong, moderately strong, limited or insufficient. The initial search in PubMed yielded 215 abstracts. Hand searches of reference lists yielded no additional original scientific articles. After a selection process and interpretation, 22 articles were included and rated for level of evidence: no article was rated as high and seven as moderate. Overall the methodological quality of studies has improved since the previous systematic review was published in 2006. The conclusions are that there is limited scientific evidence that application of calcium hydroxide or mineral trioxide aggregate to an exposed pulp frequently results in formation of a hard tissue barrier, whereas adhesives or enamel matrix derivatives do not. There is insufficient scientific evidence that mineral trioxide aggregate promotes hard tissue formation more frequently than calcium hydroxide. PMID:26059916

  16. Preparation and Characterization of Biomimetic Hydroxyapatite-Resorbable Polymer Composites for Hard Tissue Repair

    NASA Astrophysics Data System (ADS)

    Hiebner, Kristopher Robert

    Autografts are the orthopedic "gold standard" for repairing bone voids. Autografts are osteoconductive and do not elicit an immune response, but they are in short supply and require a second surgery to harvest the bone graft. Allografts are currently the most common materials used for the repair of segmental defects in hard tissue. Unlike autografts, allografts can cause an undesirable immune response and the possibility of disease transmission is a major concern. As an alternative to the above approaches, recent research efforts have focused on the use of composite materials made from hydroxyapatite (HA) and bioresorbable polymers, such as poly-L-lactide (PLLA). Recent results have shown that the surface hydroxides on HA can initiate the ring opening polymerization (ROP) of L-lactide and other lactones creating a composite with superior interfacial strength. This thesis demonstrates that the surface of porous biologically derived HA substrates, such as coralline HA and trabecular bone, can be used to initiate the ROP of L-lactide and other lactones from the vapor phase. This process increases the strength of the porous scaffold through the deposition of a thin, uniform polymer coating, while maintaining the porous structure. The kinetics of the chemical vapor deposition polymerization (CVDP) are described using a quartz crystal microbalance (QCM). The reaction temperature and monomer vapor pressure are found to affect the rate of the polymerization. Also described in this thesis is the preparation of a porous polymer scaffold that mimics the structure of demineralized bone matrix (DBM). This demineralized bone matrix simulant (DBMS) is created using anorganic bovine bone as a template to initiate the polymerization of various lactones, followed by the removal of the HA scaffold. This material retained its shape and exhibits mechanical properties superior to DBM. Finally it is shown that HA can be used to initiate the ROP of a-caprolactam and the biocompatibility

  17. [Tooth regeneration--dream to reality].

    PubMed

    Wang, Song-Ling; Wang, Xue-Jiu

    2008-04-01

    Tooth or dentition missing compromises human health physically and psychiatrically. Although several prosthesis methods are used to restore tooth loss, these restorations are still non-biological methods. It is a dream for human being to regenerate a real tooth for hundreds years. There are two ways to regenerate the tooth. One is application of conventional tissue engineering techniques including seed cells and scaffold. The other is regeneration tooth using dental epithelium and dental mesenchymal cells based on the knowledge of tooth initiation and development. Marked progress has been achieved in these two ways, while there is still a long way to go. Recently a new concept has been proposed for regeneration of a biological tooth root based on tooth-related stem cells and tissue engineering technique. A biological tooth root has been regenerated in swine. It may be a valuable method for restoration of tooth loss before successful whole tooth regeneration. A latest research showed that a subpopulation in bone marrow cells can give rise to ameloblast-like cells when mixed with embryonic epithelium and reassociation with integrated mesenchyme, which may provide a new seed cell source for tooth regeneration. PMID:18605442

  18. Intra-oral PTH Administration Promotes Tooth Extraction Socket Healing

    PubMed Central

    Kuroshima, S.; Kovacic, B.L.; Kozloff, K.M.; McCauley, L.K.; Yamashita, J.

    2013-01-01

    Intermittent parathyroid hormone (PTH) administration increases systemic and craniofacial bone mass. However, the effect of PTH therapy on healing of tooth extraction sites is unknown. The aims of this study were to determine the effect of PTH therapy on tooth extraction socket healing and to examine whether PTH intra-oral injection promotes healing. The mandibular first molars were extracted in rats, and subcutaneous PTH was administered intermittently for 7, 14, and 28 days. In a second study, maxillary second molars were extracted, and PTH was administered by either subcutaneous or intra-oral injection to determine the efficacy of intra-oral PTH administration. Healing was assessed by micro-computed tomography and histomorphometric analyses. PTH therapy accelerated the entire healing process and promoted both hard- and soft-tissue healing by increasing bone fill and connective tissue maturation. PTH therapy by intra-oral injection was as effective as subcutaneous injection in promoting tooth extraction socket healing. The findings suggest that PTH therapy promotes tooth extraction socket healing and that intra-oral injections can be used to administer PTH. PMID:23611925

  19. Influence of static pressure on dynamic characteristics of laser-induced cavitation and hard-tissue ablation under liquid environment

    NASA Astrophysics Data System (ADS)

    Chen, Chuanguo; Li, Xuwei; Zhang, Xianzeng; Zhan, Zhenlin; Xie, Shusen

    2014-11-01

    Several studies have demonstrated that laser-induced hard tissue ablation effects can be enhanced by applying an additional water-layer on tissue surface. However, the related mechanism has not yet been presented clearly. In this paper, the influence of static pressure on dynamic characteristics of cavitation induced by pulse laser in liquid and its effect on bovine shank bone ablation were investigated. The laser source is fiber-guided free-running Ho:YAG laser with wavelength of 2080 nm, pulse duration of 350 μs and energy of 1600 mJ. The tissue samples were immerged in pure water at different depths of 11, 16, 21, 26 and 31 mm. The working distance between the fiber tip and tissue surface was fixed at 1 mm for all studies. The dynamic interaction between laser, water and tissue were recorded by high-speed camera, and the morphological changes of bone tissue were assessed by stereomicroscope and OCT. The results showed that many times expansion and collapse of bubble were observed, more than four pulsation periods were accurately achieved with the most energy deposited in the first period and the bubble became more and more irregular in shape. The longitudinal length (7.49--6.74 mm) and transverse width (6.69--6.08 mm) of bubble were slowly decreased while volume (0.0586--0.0124 mm3) of ablation craters were drastically reduced, with static pressure increasing. The results also presented that the water-layer on hard-tissue surface can not only reduce thermal injury but also improve lubricity of craters, although the water-layer reduced ablation efficiency.

  20. Tooth - abnormal colors

    MedlinePlus

    ... things can cause tooth discoloration. The change in color may affect the entire tooth, or appear as spots or ... the tooth enamel. Your genes affect your tooth color. Other things ... include: Congenital diseases Environmental factors Infections ...

  1. Tooth Decay

    MedlinePlus

    ... decay starts in the outer layer, called the enamel. Without a filling, the decay can get deep into the tooth and its nerves and cause a toothache or abscess. To help prevent cavities Brush your teeth every day with a fluoride toothpaste Clean between ...

  2. Impacted tooth

    MedlinePlus

    ... Unerupted tooth References Buttaravoli P, Leffler SM, eds. Dental pain, pericoronitis. Minor Emergencies . 3rd ed. Philadelphia, PA: Elsevier Mosby; 2012:chap 46. Read More Abscess ... Updated by: Ilona Fotek, DMD, MS, Palm Beach Prosthodontics Dental Associates, West Palm Beach, FL. Review provided by ...

  3. Ablation of hard dental tissues with an ArF-pulsed excimer laser

    NASA Astrophysics Data System (ADS)

    Neev, Joseph; Raney, Daniel; Whalen, William E.; Fujishige, Jack T.; Ho, Peter D.; McGrann, John V.; Berns, Michael W.

    1991-06-01

    The interaction of 15 ns pulses from an ArF excimer laser with hard dental tissue was investigated for the purpose of obtaining practical information on the ablation process. Dark field fast photography utilizing an auxiliary, 15 ns Nd:Yag laser 'probe', was used to study the ablation plume dynamics as a function of time, luminescence were studied at different fluence levels and prr. Dentin ablation was found to be about four times as efficient as ablation of enamel in the higher fluence levels tested (> 10 J/cm2) and about twice as efficient as the ablation in the lower fluence regime (approximately equals 1 J/cm2). The dentin etch depth per pulse was found to increase exponentially with fluence (at least up to the tested level of 11 J/cm2), while in enamel the etch depth per pulse appears to increase logarithmically with fluence. Dentin ablation yields a larger, more dense plume which can be ejected (depending on the fluence level) to a height of several millimeters above the surface with observed ejection velocity in access of 1200 m/s. The dentin plume consisted of a relatively uniform particle size distribution (0.1 micrometers to 10 micrometers in diameter). Enamel ablation, on the other hand, yields a smaller observed ejection velocities (about 800 m/s), and a much smaller plume of fine particles (about 0.1 micrometers in diameter) and gases, confined to within 0.5 mm of the surface. In addition, an even smaller amount of highly non-uniform debris, (from ten to several hundred micrometers in size) is observed to be ejected to higher levels, and reach roughly half the height of the corresponding dentin plume for similar fluence levels. Although both dentin and enamel yield lower ablation efficiencies at 1 Hz, no significant difference is detected between the ablation efficiency at 5 Hz and ablation 10 Hz prr. Both materials remained within 20 degree(s)C of room temperature even at fluences as high as 20 J/cm2 and prr as high as 10 Hz for enamel and 20 Hz for

  4. Test Tube Tooth: The Next Big Thing.

    PubMed

    Yadav, Preeti; Tahir, Mohammed; Yadav, Harsh; Sureka, Rakshit; Garg, Aarti

    2016-06-01

    Unlike some vertebrates and fishes, humans do not have the capacity for tooth regeneration after the loss of permanent teeth. Although artificial replacement with removable dentures, fixed prosthesis and implants is possible through advances in the field of prosthetic dentistry, it would be ideal to recreate a third set of natural teeth to replace lost dentition. For many years now, researchers in the field of tissue engineering have been trying to bioengineer dental tissues as well as whole teeth. In order to attain a whole tooth through dental engineering, that has the same or nearly same biological, mechanical and physical properties of a natural tooth, it's necessary to deal with all the cells and tissues which are concerned with the formation, maintenance and repair of the tooth. In this article we review the steps involved in odontogenesis or organogenesis of a tooth and progress in the bioengineering of a whole tooth. PMID:27504430

  5. Test Tube Tooth: The Next Big Thing

    PubMed Central

    Tahir, Mohammed; Yadav, Harsh; Sureka, Rakshit; Garg, Aarti

    2016-01-01

    Unlike some vertebrates and fishes, humans do not have the capacity for tooth regeneration after the loss of permanent teeth. Although artificial replacement with removable dentures, fixed prosthesis and implants is possible through advances in the field of prosthetic dentistry, it would be ideal to recreate a third set of natural teeth to replace lost dentition. For many years now, researchers in the field of tissue engineering have been trying to bioengineer dental tissues as well as whole teeth. In order to attain a whole tooth through dental engineering, that has the same or nearly same biological, mechanical and physical properties of a natural tooth, it’s necessary to deal with all the cells and tissues which are concerned with the formation, maintenance and repair of the tooth. In this article we review the steps involved in odontogenesis or organogenesis of a tooth and progress in the bioengineering of a whole tooth. PMID:27504430

  6. trkA modulation of developing somatosensory neurons in oro-facial tissues: tooth pulp fibers are absent in trkA knockout mice.

    PubMed

    Matsuo, S; Ichikawa, H; Henderson, T A; Silos-Santiago, I; Barbacid, M; Arends, J J; Jacquin, M F

    2001-01-01

    To investigate the nerve growth factor requirement of developing oro-facial somatosensory afferents, we have studied the survival of sensory fibers subserving nociception, mechanoreception or proprioception in receptor tyrosine kinase (trkA) knockout mice using immunohistochemistry. trkA receptor null mutant mice lack nerve fibers in tooth pulp, including sympathetic fibers, and showed only sparse innervation of the periodontal ligament. Ruffini endings were formed definitively in the periodontal ligament of the trkA knockout mice, although calcitonin gene-related peptide- and substance P-immunoreactive fibers were reduced in number or had disappeared completely. trkA gene deletion had also no obvious effect on the formation of Meissner corpuscles in the palate. In the vibrissal follicle, however, some mechanoreceptive afferents were sensitive for trkA gene deletion, confirming a previous report [Fundin et al. (1997) Dev. Biol. 190, 94-116]. Moreover, calretinin-positive fibers innervating longitudinal lanceolate endings were completely lost in trkA knockout mice, as were the calretinin-containing parent cells in the trigeminal ganglion.These results indicate that trkA is indispensable for developing nociceptive neurons innervating oral tissues, but not for developing mechanoreceptive neurons innervating oral tissues (Ruffini endings and Meissner corpuscles), and that calretinin-containing, trkA dependent neurons in the trigeminal ganglion normally participate in mechanoreception through longitudinal lanceolate endings of the vibrissal follicle. PMID:11516838

  7. Generation of radicals in hard biological tissues under the action of laser radiation

    NASA Astrophysics Data System (ADS)

    Sviridov, Alexander P.; Bagratashvili, Victor N.; Sobol, Emil N.; Omelchenko, Alexander I.; Lunina, Elena V.; Zhitnev, Yurii N.; Markaryan, Galina L.; Lunin, Valerii V.

    2002-07-01

    The formation of radicals upon UV and IR laser irradiation of some biological tissues and their components was studied by the EPR technique. The radical decay kinetics in body tissue specimens after their irradiation with UV light were described by various models. By the spin trapping technique, it was shown that radicals were not produced during IR laser irradiation of cartilaginous tissue. A change in optical absorption spectra and the dynamics of optical density of cartilaginous tissue, fish scale, and a collagen film under exposure to laser radiation in an air, oxygen, and nitrogen atmosphere was studied.

  8. Multivariate image analysis of laser-induced photothermal imaging used for detection of caries tooth

    NASA Astrophysics Data System (ADS)

    El-Sherif, Ashraf F.; Abdel Aziz, Wessam M.; El-Sharkawy, Yasser H.

    2010-08-01

    Time-resolved photothermal imaging has been investigated to characterize tooth for the purpose of discriminating between normal and caries areas of the hard tissue using thermal camera. Ultrasonic thermoelastic waves were generated in hard tissue by the absorption of fiber-coupled Q-switched Nd:YAG laser pulses operating at 1064 nm in conjunction with a laser-induced photothermal technique used to detect the thermal radiation waves for diagnosis of human tooth. The concepts behind the use of photo-thermal techniques for off-line detection of caries tooth features were presented by our group in earlier work. This paper illustrates the application of multivariate image analysis (MIA) techniques to detect the presence of caries tooth. MIA is used to rapidly detect the presence and quantity of common caries tooth features as they scanned by the high resolution color (RGB) thermal cameras. Multivariate principal component analysis is used to decompose the acquired three-channel tooth images into a two dimensional principal components (PC) space. Masking score point clusters in the score space and highlighting corresponding pixels in the image space of the two dominant PCs enables isolation of caries defect pixels based on contrast and color information. The technique provides a qualitative result that can be used for early stage caries tooth detection. The proposed technique can potentially be used on-line or real-time resolved to prescreen the existence of caries through vision based systems like real-time thermal camera. Experimental results on the large number of extracted teeth as well as one of the thermal image panoramas of the human teeth voltanteer are investigated and presented.

  9. [Biomechanical study of medical hard tissue adhesive bonding butterfly fracture fragment in middle part of fresh human tibia].

    PubMed

    Lu, Bo; Tu, Zhongqi; Pei, Fuxing; Chen, Mengshi; Liu, Lei

    2004-06-01

    A medical hard tissue adhesive, octyl-a-cyanoacrylate, was tested in 6 fresh human tibiae. A 90 degrees butter-fly fracture fragment was made in the middle part of tibia by bandsaw. The compressive stress, torsional stress and angular deflection were assessed before and after osteoectomy respectively. After adhesive bonding, the compressive stress, torsional stress and angular deflection were tested again. The butterfly fracture fagment decreased the bending strength, torsion strength, yielding strength of tibia bone. In torsion test, the torque of tibia before osteoectomy is greater than bonded tibia, the bonded tibia is greater than that of the unbonded tibia. In compression test, before adhesive bonding broken, the compressive curve slope of tibia before osteoectomy is greater than that of bonded tibia, the bonded tibia is greater than that of the unbonded tibia. In angular deflection test before adhesive bonding of broken,the curve slope of tibia before osteoectomy is not different from that of bonded tibia (P>0.05), the slope the bonded tibia is greater than the slope of unbonded tibia(P<0.05). The elastic modulus, rigidity coefficient and moment of area inertia show no statistical difference between the bonded tibia and intact tibia. The used of medical hard tissue adhesive to bond the fracture fragment could improve the bending strength, torsion strength, yielding strength of tibia bone. In operation, it can reduce the soft tissue injury when the fracture fragment is being fixed, and this will benefit bone healing. PMID:15250133

  10. Ectopic Hard Tissue Formation by Odonto/Osteogenically In Vitro Differentiated Human Deciduous Teeth Pulp Stem Cells.

    PubMed

    Kim, Seunghye; Song, Je Seon; Jeon, Mijeong; Shin, Dong Min; Kim, Seong-Oh; Lee, Jae Ho

    2015-07-01

    There have been many attempts to use the pulp tissue from human deciduous teeth for dentin or bone regeneration. The objective of this study was to determine the effects of odonto/osteogenic in vitro differentiation of deciduous teeth pulp stem cells (DTSCs) on their in vivo hard tissue-forming potential. DTSCs were isolated from extracted deciduous teeth using the outgrowth method. These cells were exposed to odonto/osteogenic stimuli for 4 and 8 days (Day 4 and Day 8 groups, respectively), while cells in the control group were cultured in normal medium. The in vitro differentiated DTSCs and the control DTSCs were transplanted subcutaneously into immunocompromised mice with macroporous biphasic calcium phosphate and sacrificed at 8 weeks post-implantation. The effect of odonto/osteogenic in vitro differentiation was evaluated using alkaline phosphatase (ALP) staining and quantitative reverse transcription polymerase chain reaction (RT-PCR). The in vivo effect was evaluated by qualitative RT-PCR, assessment of ALP activity, histologic analysis, and immunohistochemical staining. The amount of hard tissue was greater in Day 4 group than Day 8 group (p = 0.014). However, Day 8 group generated lamellar bone-like structure, which was immunonegative to anti-human dentin sialoprotein with significantly low expression level of DSPP compared with the control group (p = 0.008). This study demonstrates that odonto/osteogenic in vitro differentiation of DTSCs enhances the formation of bone-like tissue, instead of dentin-like tissue, when transplanted subcutaneously using MBCP as a carrier. The odonto/osteogenic in vitro differentiation of DTSCs may be an effective modification that enhances in vivo bone formation by DTSCs. PMID:25894066

  11. Iterative reconstruction algorithm for analyzer-based phase-contrast computed tomography of hard and soft tissue

    NASA Astrophysics Data System (ADS)

    Sunaguchi, Naoki; Yuasa, Tetsuya; Ando, Masami

    2013-09-01

    We propose a reconstruction algorithm for analyzer-based phase-contrast computed tomography (CT) applicable to biological samples including hard tissue that may generate conspicuous artifacts with the conventional reconstruction method. The algorithm is an iterative procedure that goes back and forth between a tomogram and its sinogram through the Radon transform and CT reconstruction, while imposing a priori information in individual regions. We demonstrate the efficacy of the algorithm using synthetic data generated by computer simulation reflecting actual experimental conditions and actual data acquired from a rat foot by a dark field imaging system.

  12. Soft and hard tissue changes in skeletal Class III patients treated with double-jaw orthognathic surgery-maxillary advancement and mandibular setback.

    PubMed

    Becker, O E; Avelar, R L; Dolzan, A do N; Haas, O L; Scolari, N; Oliveira, R B de

    2014-02-01

    The soft tissues of the facial profile may change after skeletal movement in orthognathic surgery. The aim of this study was to evaluate and compare the differences and correlation between hard and soft tissues after double-jaw surgery in skeletal Class III subjects. Radiographs from the following time points were assessed using Dolphin Imaging software: preoperative (T0), 2-4 months postoperative (T1), and 6-12 months postoperative (T2). Eleven hard and soft tissue points of the facial profile were evaluated. The Student's t-test was used to assess the significance of differences between the time intervals; Pearson's correlation coefficient was used to assess the significance of correlation existing between these points; significance was set at P<0.05. In the sample of 58 subjects, the correlation between hard and soft tissues in the mandible was greater than in the maxilla. Similarly, the correlations only between hard tissues and only between soft tissues presented a greater correlation in the mandible. The results are similar to those found in studies on single-jaw surgery for both the maxilla and the mandible. The influence of movements in hard tissues was restricted to the soft tissues of the same jaw, although there were exceptions. PMID:23870542

  13. Investigation of normal and pathological parodontium tissue autofluorescence images

    NASA Astrophysics Data System (ADS)

    Berezin, Anatoly N.; Kiselev, Gennady L.; Volkova, Anna I.; Loschenov, Victor B.; Sinyaeva, Maria L.; Mamedov, Ad. A.; Lervkin, V. V.; Kharnas, Sergey S.

    2004-07-01

    During the last several years research activities have been carried out to study the fluorescent images of hard tooth tissues and demineralization enamel nidus. Also it is well known about availability of photodynamic therapy (PDT) for pathogenic microflora suppression, which presence leads to different parodontium diseases. Our laboratory carried out research of fluorescent images and spectra of different parodontium tissues in order to develop the method of fluorescent diagnostics (PD) of tissue inflammatory disease according to autofluorescence intensity in pathologic and normal tissues.

  14. The use of nanoindentation for characterizing the properties of mineralized hard tissues: state-of-the art review.

    PubMed

    Lewis, Gladius; Nyman, Jeffry S

    2008-10-01

    The use of nanoindentation to determine nanomechanical properties of mineralized tissues has been investigated extensively. A detailed, critical, and comprehensive review of this literature is the subject of the present work. After stating the motivation for the review, a succinct presentation of the challenges, advantages, and disadvantages of the various quasi-static nanoindentation test methods (to obtain elastic modulus, E, and hardness, H) and dynamic test methods (to obtain storage and loss moduli and/or loss/damping factor) is given in the form of a primer. Explicative summaries of literature reports on various intrinsic and extrinsic factors that significantly influence E and H, followed by 15 suggested topics for future research, are included additionally. This review is designed to present a compact guide to the principles of the nanoindentation technique and to emphasize considerations when determining material properties of mineralized tissues. PMID:18395829

  15. The teamwork approach to esthetic tooth replacement with immediate implant placement and immediate temporization.

    PubMed

    Levin, Barry P; Wilk, Brian L

    2015-10-01

    Enduring a period of edentulism between extraction and final restoration is difficult for patients- especially when it concerns the esthetic zone. The approach described demonstrates key points of consideration when replacing a maxillary anterior tooth with a dental implant using immediate implant placement, hard- and soft-tissue augmentation, and provisionalization. The authors stress adherence to patient selection and prosthetic design guidelines, and recommend the use of a digital impression technique, rather than traditional, rubber-based impressions. PMID:26448151

  16. Preserved microstructure and mineral distribution in tooth and periodontal tissues in early fossil hominin material from Koobi Fora, Kenya.

    PubMed

    Klinge, R Furseth; Dean, M C; Risnes, S; Erambert, M; Gunnaes, A E

    2009-01-01

    The aim of this study was to explore further the preservation of tissues and the mineral distribution in 1.6 million-year-old fossil hominin material from Koobi Fora, Kenya attributed to Paranthropus boisei (KNM-ER 1817). Bone, dentine and cementum microstructure were well preserved. Electron microprobe analysis of dentine and bone revealed an F-bearing apatite. Calcite now filled the original soft tissue spaces. The average Ca/P atomic ratio was 1.93, as compared to 1.67 in biological hydroxyapatite, indicating that the Ca-content had increased during fossilization. Analytical sums for mineral content were approximately 90 wt%. Some of the remaining 10 wt% may be preserved organic material. Demineralized dentine fragments showed irregularly distributed tubules encircled with a fibrous-like electron-dense material. A similar material was observed in demineralized dentine. Within this, structures resembling bacteria were seen. In demineralized bone an electron-dense material with a fibrous appearance and a banding pattern that repeated every 64 nm, similar to that of collagen, was noted. SEM of an enamel fragment (KNM-ER 6081) showed signs of demineralization/remineralization. Retzius lines, Hunter-Schreger bands and prism cross-striations spaced 3.7-7.1.microm apart were noted. Prisms were arranged in a pattern 3 configuration and deeper areas containing aprismatic enamel were occasionally observed. We conclude that a great deal of informative microstructure and ultrastructure remains preserved in this fossil material. We also hypothesize that the high mineral content of the tissues may 'protect' parts of the organic matrix from degradation, since our findings indicate that some organic matrix may still be present. PMID:19828965

  17. TLR signalling can modify the mineralization of tooth germ.

    PubMed

    Papp, Tamas; Hollo, Krisztina; Meszar-Katona, Eva; Nagy, Zoltan; Polyak, Angela; Miko, Edit; Bai, Peter; Felszeghy, Szabolcs

    2016-05-01

    Objective The aim of this work is to investigate the possible role of Toll-like receptor 4 (TLR4) during the development of mouse tooth germ. TLR4 is well known to inhibit mineralization and cause inflammation in mature odontoblasts and dental pulp cells. However, unlike these pathological functions of TLR4, little is known about the developmental function(s) of TLR4 during tooth development. Materials and methods TLR4 expression was studied via Western blot in developing lower mouse incisors from E13.5 to E18.5. To generate functional data about the effects of TLR4, a specific agonist (LPS) was applied to the medium of in vitro tooth germ cultures, followed by Western blot, histochemical staining, ELISA assay, in situ hybridization and RT-qPCR. Results Increased accumulation of biotin-labelled LPS was detected in the enamel organ and in preodontoblasts. LPS treatment induced degradation of the inhibitor molecule (IκB) of the NF-κB signalling pathway. However, no morphological alterations were detected in cultured tissue after LPS addition at the applied dosage. Activation of TLR4 inhibited the mineralization of enamel and dentin, as demonstrated by alizarin red staining and as decreased levels of collagen type X. mRNA expression of ameloblastin was elevated after LPS administration. Conclusion These results demonstrate that TLR4 may decrease the mineralization of hard tissues of the tooth germ and may trigger the maturation of ameloblasts; it can give valuable information to understand better congenital tooth abnormalities. PMID:26763602

  18. [Experience with the clinical use of HTR (hard tissue replacement) polymer. Sinus elevation, human histological studies].

    PubMed

    Suba, Z; Szabó, G; Haris, A; Divinyi, T; Martonffy, K

    1991-03-01

    The HTR polymer was employed under clinical circumstances. Results supported that the HTR polymer may well be employed for bone replacement. The forming of the support tissue between the plastic granulums has been accompanied with biopsies. Though in some cases giant cell reaction of alien body type have been observed, yet this has never been of such degree that it would have impeded the reception of the stuff. According to the authors opinion after reinforcement of the lower wall of the facial cavity with HTR polymert in 8 to 10 months an enduring suitable support tissue is formed. PMID:1855596

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

    PubMed

    Chun, Keyoung Jin; 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

  20. 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

  1. Observation of a Soft Tissue by a Zernike Phase Contrast Hard X-ray Microscope

    NASA Astrophysics Data System (ADS)

    Aoki, Sadao; Namikawa, Tadahiro; Hoshino, Masato; Watanabe, Norio

    2007-01-01

    A Zernike-type phase contrast hard X-ray microscope was constructed at the Photon Factory BL3C2 (KEK). A white beam from a bending magnet was monochromatized by a silicon double crystal monochromator. Monochromatic parallel X-ray beam illuminated a sample, and transmitted and diffracted X-ray beams were imaged by a Fresnel zone plate (FZP) which had the outer zone width of 100 nm. A phase plate made of a thin aluminum foil with a pinhole was set at the back focal plane of the FZP. The phase plate modulated the diffraction beam from the FZP, whereas a direct beam passed through the pinhole. The resolution of the microscope was measured by observing a tantalum test pattern at an X-ray energy of 9 keV. A 100nm line-and-space pattern could be resolved. X-ray montage pictures of growing eggs of artemia (plankton) were obtained.

  2. Observation of a Soft Tissue by a Zernike Phase Contrast Hard X-ray Microscope

    SciTech Connect

    Aoki, Sadao; Namikawa, Tadahiro; Hoshino, Masato; Watanabe, Norio

    2007-01-19

    A Zernike-type phase contrast hard X-ray microscope was constructed at the Photon Factory BL3C2 (KEK). A white beam from a bending magnet was monochromatized by a silicon double crystal monochromator. Monochromatic parallel X-ray beam illuminated a sample, and transmitted and diffracted X-ray beams were imaged by a Fresnel zone plate (FZP) which had the outer zone width of 100 nm. A phase plate made of a thin aluminum foil with a pinhole was set at the back focal plane of the FZP. The phase plate modulated the diffraction beam from the FZP, whereas a direct beam passed through the pinhole. The resolution of the microscope was measured by observing a tantalum test pattern at an X-ray energy of 9 keV. A 100nm line-and-space pattern could be resolved. X-ray montage pictures of growing eggs of artemia (plankton) were obtained.

  3. Dual Contrast Agent for Computed Tomography and Magnetic Resonance Hard Tissue Imaging

    PubMed Central

    Ventura, Manuela; Sun, Yi; Rusu, Viorel; Laverman, Peter; Borm, Paul; Heerschap, Arend; Oosterwijk, Egbert; Boerman, Otto C.; Walboomers, X. Frank

    2013-01-01

    Calcium phosphate cements (CPCs) are commonly used bone substitute materials, which closely resemble the composition of the mineral phase of bone. However, this high similarity to natural bone also results in difficult discrimination from the bone tissue by common imaging modalities, that is, plain X-ray radiography and three-dimensional computed tomography (CT). In addition, new imaging techniques introduced for bone tissue visualization, like magnetic resonance imaging (MRI), face a similar problem. Even at high MRI resolution, the lack of contrast between CPCs and surrounding bone is evident. Therefore, this study aimed to evaluate the feasibility of a dual contrast agent, traceable with both CT and MRI as enhancers of CPC/bone tissue contrast. Our formulation is based on the use of silica beads as vectors, which encapsulate and carry contrast-enhancing nanoparticles, in our case, colloidal Gold and Superparamagnetic Iron oxide particles (SPIO). The bead suspension was incorporated within a calcium phosphate powder. The resultant cements were then tested both in vitro and in vivo in a femoral condyle defect model in rats. Results showed that the mechanical properties of the cement were not significantly affected by the inclusion of the beads. Both in vitro and in vivo data proved the homogeneous incorporation of the contrast within the cement and its visual localization, characterized by a short-term CT contrast enhancement and a long-term MR effect recognizable by the characteristic blooming shape. Finally, no signs of adverse tissue reactions were noticed in vivo. In conclusion, this study proved the feasibility of a multimodal contrast agent as an inert and biocompatible enhancer of CaP cement versus bone tissue contrast. PMID:23259682

  4. Distinctive Tooth-Extraction Socket Healing: Bisphosphonate Versus Parathyroid Hormone Therapy

    PubMed Central

    Kuroshima, Shinichiro; Mecano, Rodan B.; Tanoue, Ryuichiro; Koi, Kiyono; Yamashita, Junro

    2014-01-01

    Background Patients with osteoporosis who receive tooth extractions are typically on either oral bisphosphonate or parathyroid hormone (PTH) therapy. Currently, the consequence of these therapies on hard- and soft-tissue healing in the oral cavity is not clearly defined. The aim of this study is to determine the differences in the therapeutic effect on tooth-extraction wound healing between bisphosphonate and PTH therapies. Methods Maxillary second molars were extracted in Sprague Dawley rats (n = 30), and either bisphosphonate (zoledronate [Zol]), PTH, or saline (vehicle control [VC]) was administered for 10 days (n = 10 per group). Hard-tissue healing was evaluated by microcomputed tomography and histomorphometric analyses. Collagen, blood vessels, inflammatory cell infiltration, and cathepsin K expression were assessed in soft tissue using immunohistochemistry, quantitative polymerase chain reaction, and immunoblotting. Results Both therapies significantly increased bone fill and suppressed vertical bone loss. However, considerably more devital bone was observed in the sockets of rats on Zol versus VC. Although Zol increased the numbers of blood vessels, the total blood vessel area in soft tissue was significantly smaller than in VC. PTH therapy increased osteoblastic bone formation and suppressed osteoclasts. PTH therapy promoted soft-tissue maturation by suppressing inflammation and stimulating collagen deposition. Conclusion Zoledronate therapy deters whereas PTH therapy promotes hard- and soft-tissue healing in the oral cavity, and both therapies prevent vertical bone loss. PMID:23688101

  5. Cavitation effect of holmium laser pulse applied to ablation of hard tissue underwater.

    PubMed

    Lü, Tao; Xiao, Qing; Xia, Danqing; Ruan, Kai; Li, Zhengjia

    2010-01-01

    To overcome the inconsecutive drawback of shadow and schlieren photography, the complete dynamics of cavitation bubble oscillation or ablation products induced by a single holmium laser pulse [2.12 microm, 300 micros (FWHM)] transmitted in different core diameter (200, 400, and 600 microm) fibers is recorded by means of high-speed photography. Consecutive images from high-speed cameras can stand for the true and complete process of laser-water or laser-tissue interaction. Both laser pulse energy and fiber diameter determine cavitation bubble size, which further determines acoustic transient amplitudes. Based on the pictures taken by high-speed camera and scanned by an optical coherent microscopy (OCM) system, it is easily seen that the liquid layer at the distal end of the fiber plays an important role during the process of laser-tissue interaction, which can increase ablation efficiency, decrease heat side effects, and reduce cost. PMID:20799845

  6. Versatile design of hydrogel-based scaffolds with manipulated pore structure for hard-tissue regeneration.

    PubMed

    Kim, WonJin; Lee, Hyeongjin; Kim, YongBok; Choi, Chang Hyun; Lee, DaeWeon; Hwang, Heon; Kim, GeunHyung

    2016-01-01

    In recent years, a variety of biomimetic hydrogel scaffolds have been used in tissue engineering because hydrogels can provide reasonable soft-tissue-like environmental conditions for various cell responses. However, although hydrogels can provide an outstanding biofunctional platform, their poor mechanical stability and low processability have been obstacles for their usage as biomedical scaffolds. To overcome this limitation, we propose a simple and versatile method using 3D printing supplemented with a low-temperature working plate and coating process to reinforce the mechanical properties and various cellular activities by accommodating the poly(ε-caprolactone) (PCL). To determine the efficiency of the method, we used two typical hydrogels (alginate and collagen), which were deposited in a multi-layer configuration, and PCL as a coating agent. The scaffolds were evaluated in terms of various physical and cellular activities (metabolic activity and osteogenic activity). Throughout the experiments, significant increases in the tensile modulus (>6-fold), cell proliferation (>1.2-fold), and calcium deposition (>1.3-fold) were observed for the hydrogel/PCL scaffolds compared to those for pure hydrogel. Based on the experimental results, we can confirm that the proposed hydrogel scaffold can be a highly promising biomedical scaffold for application in tissue regeneration. PMID:27586518

  7. TOPICAL REVIEW: Stem cell technology using bioceramics: hard tissue regeneration towards clinical application

    NASA Astrophysics Data System (ADS)

    Ohnishi, Hiroe; Oda, Yasuaki; Ohgushi, Hajime

    2010-02-01

    Mesenchymal stem cells (MSCs) are adult stem cells which show differentiation capabilities toward various cell lineages. We have already used MSCs for treatments of osteoarthritis, bone necrosis and bone tumor. For this purpose, culture expanded MSCs were combined with various ceramics and then implanted. Because of rejection response to allogeneic MSC implantation, we have utilized patients' own MSCs for the treatment. Bone marrow is a good cell source of MSCs, although the MSCs also exist in adipose tissue. When comparing osteogenic differentiation of these MSCs, bone marrow MSCs show more extensive bone forming capability than adipose MSCs. Thus, the bone marrow MSCs are useful for bone tissue regeneration. However, the MSCs show limited proliferation and differentiation capabilities that hindered clinical applications in some cases. Recent advances reveal that transduction of plural transcription factors into human adult cells results in generation of new type of stem cells called induced pluripotent stem cells (iPS cells). A drawback of the iPS cells for clinical applications is tumor formation after their in vivo implantation; therefore it is difficult to use iPS cells for the treatment. To circumvent the problem, we transduced a single factor of either SOX2 or NANOG into the MSCs and found high proliferation as well as osteogenic differentiation capabilities of the MSCs. The stem cells could be combined with bioceramics for clinical applications. Here, we summarize our recent technologies using adult stem cells in viewpoints of bone tissue regeneration.

  8. Dental Caries (Tooth Decay)

    MedlinePlus

    ... Find Data by Topic > Dental Caries (Tooth Decay) Dental Caries (Tooth Decay) Main Content Dental caries (tooth decay) remains the most prevalent chronic ... important source of information on oral health and dental care in the United States since the early ...

  9. Seal Out Tooth Decay

    MedlinePlus

    ... Topics > Tooth Decay (Caries) > Seal Out Tooth Decay Seal Out Tooth Decay Main Content What are dental ... back teeth decay so easily? Who should get seal​ants? Should sealants be put on baby teeth? ...

  10. Role of mineralization inhibitors in the regulation of hard tissue biomineralization: relevance to initial enamel formation and maturation

    PubMed Central

    Margolis, Henry C.; Kwak, Seo-Young; Yamazaki, Hajime

    2014-01-01

    Vertebrate mineralized tissues, i.e., enamel, dentin, cementum, and bone, have unique hierarchical structures and chemical compositions. Although these tissues are similarly comprised of a crystalline calcium apatite mineral phase and a protein component, they differ with respect to crystal size and shape, level and distribution of trace mineral ions, the nature of the proteins present, and their relative proportions of mineral and protein components. Despite apparent differences, mineralized tissues are similarly derived by highly concerted extracellular processes involving matrix proteins, proteases, and mineral ion fluxes that collectively regulate the nucleation, growth and organization of forming mineral crystals. Nature, however, provides multiple ways to control the onset, rate, location, and organization of mineral deposits in developing mineralized tissues. Although our knowledge is quite limited in some of these areas, recent evidence suggests that hard tissue formation is, in part, controlled through the regulation of specific molecules that inhibit the mineralization process. This paper addresses the role of mineralization inhibitors in the regulation of biological mineralization with emphasis on the relevance of current findings to the process of amelogenesis. Mineralization inhibitors can also serve to maintain driving forces for calcium phosphate precipitation and prevent unwanted mineralization. Recent evidence shows that native phosphorylated amelogenins have the capacity to prevent mineralization through the stabilization of an amorphous calcium phosphate precursor phase, as observed in vitro and in developing teeth. Based on present findings, the authors propose that the transformation of initially formed amorphous mineral deposits to enamel crystals is an active process associated with the enzymatic processing of amelogenins. Such processing may serve to control both initial enamel crystal formation and subsequent maturation. PMID:25309443

  11. Intrafibrillar silicification of collagen scaffolds for sustained release of stem cell homing chemokine in hard tissue regeneration.

    PubMed

    Niu, Li-Na; Jiao, Kai; Qi, Yi-Pin; Nikonov, Sergey; Yiu, Cynthia K Y; Arola, Dwayne D; Gong, Shi-Qiang; El-Marakby, Ahmed; Carrilho, Marcela R O; Hamrick, Mark W; Hargreaves, Kenneth M; Diogenes, Anibal; Chen, Ji-Hua; Pashley, David H; Tay, Franklin R

    2012-11-01

    Traditional bone regeneration strategies relied on supplementation of biomaterials constructs with stem or progenitor cells or growth factors. By contrast, cell homing strategies employ chemokines to mobilize stem or progenitor cells from host bone marrow and tissue niches to injured sites. Although silica-based biomaterials exhibit osteogenic and angiogenic potentials, they lack cell homing capability. Stromal cell-derived factor-1 (SDF-1) plays a pivotal role in mobilization and homing of stem cells to injured tissues. In this work, we demonstrated that 3-dimensional collagen scaffolds infiltrated with intrafibrillar silica are biodegradable and highly biocompatible. They exhibit improved compressive stress-strain responses and toughness over nonsilicified collagen scaffolds. They are osteoconductive and up-regulate expressions of osteogenesis- and angiogenesis-related genes more significantly than nonsilicified collagen scaffolds. In addition, these scaffolds reversibly bind SDF-1α for sustained release of this chemokine, which exhibits in vitro cell homing characteristics. When implanted subcutaneously in an in vivo mouse model, SDF-1α-loaded silicified collagen scaffolds stimulate the formation of ectopic bone and blood capillaries within the scaffold and abrogate the need for cell seeding or supplementation of osteogenic and angiogenic growth factors. Intrafibrillar-silicified collagen scaffolds with sustained SDF-1α release represent a less costly and complex alternative to contemporary cell seeding approaches and provide new therapeutic options for in situ hard tissue regeneration. PMID:22859369

  12. Equine Odontoclastic Tooth Resorption and Hypercementosis: Histopathologic Features.

    PubMed

    Smedley, R C; Earley, E T; Galloway, S S; Baratt, R M; Rawlinson, J E

    2015-09-01

    Equine odontoclastic tooth resorption and hypercementosis (EOTRH) is a painful progressive condition of older horses that involves multiple teeth, including canines and incisors. EOTRH is uncommonly recognized by veterinary pathologists and in some cases may be misdiagnosed as cementoblastoma. The cause is unknown. The goals of this study were to describe the histopathologic features of EOTRH in 17 affected horses from the United States and to increase awareness of this condition. Samples ranged from affected tooth to the entire rostral mandible and maxilla. Affected teeth exhibited cemental hyperplasia and lysis. The marked proliferation of cementum in severe cases caused bulbous enlargement of the intra-alveolar portions of affected teeth. Several teeth contained necrotic debris, bacteria, and plant material in the regions of cemental lysis. All horses exhibited dentinal lysis in at least affected tooth, and several contained necrotic debris in these regions. Endodontic disease was often present with inflammation, lysis, necrotic debris, fibrosis, and/or a thin rim of atubular mineralized tissue in the pulp cavity. Periodontal disease was a common feature that was primarily characterized by moderate lymphoplasmacytic inflammation. Resorption with secondary hypercementosis appears to begin on the external surface of the teeth rather than within the pulp cavity. Distinguishing EOTRH from other diseases requires a complete history that includes the number and location of affected teeth, a gross description of regional hard/soft tissue health, and radiographic findings. PMID:26077784

  13. Robocasting nanocomposite scaffolds of poly(caprolactone)/hydroxyapatite incorporating modified carbon nanotubes for hard tissue reconstruction.

    PubMed

    Dorj, Biligzaya; Won, Jong-Eun; Kim, Joong-Hyun; Choi, Seong-Jun; Shin, Ueon Sang; Kim, Hae-Won

    2013-06-01

    Nanocomposite scaffolds with tailored 3D pore configuration are promising candidates for the reconstruction of bone. Here we fabricated novel nanocomposite bone scaffolds through robocasting. Poly(caprolactone) (PCL)-hydroxyapatite (HA) slurry containing ionically modified carbon nanotubes (imCNTs) was robotic-dispensed and structured layer-by-layer into macrochanneled 3D scaffolds under adjusted processing conditions. Homogeneous dispersion of imCNTs (0.2 wt % relative to PCL-HA) was achieved in acetone, aiding in the preparation of PCL-HA-imCNTs slurry with good mixing property. Incorporation of imCNTs into PCL-HA composition significantly improved the compressive strength and elastic modulus of the robotic-dispensed scaffolds (~1.5-fold in strength and ~2.5-fold in elastic modulus). When incubated in simulated body fluid (SBF), PCL-HA-imCNT nanocomposite scaffold induced substantial mineralization of apatite in a similar manner to the PCL-HA scaffold, which was contrasted in pure PCL scaffold. MC3T3-E1 cell culture on the scaffolds demonstrated that cell proliferation levels were significantly higher in both PCL-HA-imCNT and PCL-HA than in pure PCL, and no significant difference was found between the nanocomposite scaffolds. When the PCL-HA-imCNT scaffold was implanted into a rat subcutaneous tissue for 4 weeks, soft fibrous tissues with neo-blood vessels formed well in the pore channels of the scaffolds without any significant inflammatory signs. Tissue reactions in PCL-HA-imCNT scaffold were similar to those in PCL-HA scaffold, suggesting incorporated imCNT did not negate the beneficial biological roles of HA. While more long-term in vivo research in bone defect models is needed to confirm clinical availability, our results suggest robotic-dispensed PCL-HA-imCNT nanocomposite scaffolds can be considered promising new candidate matrices for bone regeneration. PMID:23184729

  14. Chick tooth induction revisited.

    PubMed

    Cai, Jinglei; Cho, Sung-Won; Ishiyama, Mikio; Mikami, Masato; Hosoya, Akihiro; Kozawa, Yukishige; Ohshima, Hayato; Jung, Han-Sung

    2009-07-15

    Teeth have been missing from Aves for almost 100 million years. However, it is believed that the avian oral epithelium retains the molecular signaling required to induce odontogenesis, and this has been widely examined using heterospecific recombinations with mouse dental mesenchyme. It has also been argued that teeth can form from the avian oral epithelium owing to contamination of the mouse mesenchyme with mouse dental epithelial cells. To investigate the possibility of tooth formation from chick oral epithelium and the characteristics of possible chick enamel, we applied LacZ transgenic mice during heterospecific recombination and examined the further tooth formation. Transmission electron microscopy was used to identify the two tissues during development after heterospecific recombination. No mixing was detected between chick oral epithelium and mouse dental mesenchyme after 2 days, and secretory ameloblasts with Tomes' processes were observed after 1 week. Teeth were formed after 3 weeks with a single cusp pattern, possibly determined by epithelial factors, which is similar to that of the avian tooth in the late Jurassic period. These recombinant teeth were smaller than mouse molars, whereas perfect structures of both ameloblasts and enamel showed histological characteristics similar to those of mice. Together these observations consistent with previous report that odontogenesis is initially directed by species-specific mesenchymal signals interplaying with common epithelial signals. PMID:19226602

  15. Bio-Corrosion Resistance and Biocompatibility of a ZrTi-BASED Bmgmc as Potential Hard Tissue Implants

    NASA Astrophysics Data System (ADS)

    Huang, Xiaobo; Zou, Jiaojuan; Wang, Chan; Hang, Ruiqiang; Qiao, Junwei; Tang, Bin

    2013-07-01

    In this study, we compared the bio-corrosion resistance and biocompatibility of a ZrTi-based BMGMC (Zr58.5Ti14.3Ni4.9Cu6.1Nb5.2Be11.0). The Ti-6Al-4V alloy was used as a reference material. By utilizing the electrochemical measurements and M3T3 cell culture, the corrosion resistance and biocompatibility of this BMGMC were evaluated. The BMGMC displayed high positive corrosion potentials and low corrosion current densities, which indicated that this material exhibited a highly improved corrosion resistance than the Ti alloy. The cells could adhere on the surface of this BMGMC and exhibited improved cellular behaviors, such as cellular viability and cytoskeketal structure. In summary, the ZrTi-based BMGMC showed great potential for applications in the hard tissue implants.

  16. Nonlinear inversion modeling for Ultrasound Computer Tomography: transition from soft to hard tissues imaging

    NASA Astrophysics Data System (ADS)

    Lasaygues, Philippe; Mensah, Serge; Guillermin, Régine; Rouyer, Julien; Franceschini, Emilie

    2012-03-01

    Ultrasound Computer Tomography (UCT) is an imaging technique which has proved effective for soft-tissue (breast, liver,...) characterization. More recently, the use of UCT has been envisaged for bone imaging. In this field, the large variations of impedance distribution (high contrast) require that a finer model of wave propagation be integrated into the reconstruction scheme. Here, the tomographic procedure used is adapted to broadband data acquired in scattering configurations while the heterogeneous objects (Born approximation) are probed by spherical waves. An "elliptical" Fourier transform has been derived to solve the near-field inverse problem. This transform differs from the standard Fourier Transform in that, instead of plane waves, families of harmonic ellipsoidal waves are considered. For soft tissues it is possible to separate the impedance and speed of sound contributions and to reconstruct their cartographies using dedicated near-field Radon transforms. In the case of highly heterogeneous media such as bones, iterative inversion schemes are proposed. The various reconstruction procedures are set against experiments.

  17. Studies of Hard and Soft Tissue Elemental Compositions in Mice and Rats Subjected to Simulated Microgravity

    NASA Astrophysics Data System (ADS)

    Mehta, Rahul; Lane, Ryan A.; Fitch, Hannah M.; Ali, Nawab; Soulsby, Michael; Chowdhury, Parimal

    2009-03-01

    Microgravity has profound effects on skeletal as well as other body systems. To investigate the effect of microgravity, we have used a NASA validated Hind-limb suspension (HLS) animal model of simulated weightlessness. Groups of mice and rats were subjected to hind limb suspension between 1 and 14 days while the control groups were maintained without suspension for the same duration. To study the effect of diet, some groups of animals were fed on a special diet with defined composition. At term, the animals were sacrificed and the tibia, femur, and skull bones were collected. In addition, soft tissues from pancreas and muscles were also collected. All of the bones and tissues samples were analyzed for elemental analysis using Energy Dispersive Spectroscopy (EDS) equipped on a Scanning Electron Microscope (SEM). In the EDS, 10-20 keV electrons bombarded the samples and a Si (Li) detector measured K-, L- and M-shell x-rays. Independently, X-Ray Fluorescence (XRF) provided the data for comparison and normalization. Flame software, with Fuzzy Logic, was used to form elemental ratios. Elemental analysis of bone samples indicated a variation in the compositional ratios of calcium, potassium, oxygen and carbon in the leg bones and skulls of the HLS versus control specimens. These variations showed dependence on sample position in the bone.

  18. Whole Tooth Regeneration as a Future Dental Treatment.

    PubMed

    Oshima, Masamitsu; Tsuji, Takashi

    2015-01-01

    Dental problems caused by dental caries, periodontal disease and tooth injury compromise the oral and general health issues. Current advances for the development of regenerative therapy have been influenced by our understanding of embryonic development, stem cell biology, and tissue engineering technology. Tooth regenerative therapy for tooth tissue repair and whole tooth replacement is currently expected a novel therapeutic concept with the full recovery of tooth physiological functions. Dental stem cells and cell-activating cytokines are thought to be candidate approach for tooth tissue regeneration because they have the potential to differentiate into tooth tissues in vitro and in vivo. Whole tooth replacement therapy is considered to be an attractive concept for next generation regenerative therapy as a form of bioengineered organ replacement. For realization of whole tooth regeneration, we have developed a novel three-dimensional cell manipulation method designated the "organ germ method". This method involves compartmentalisation of epithelial and mesenchymal cells at a high cell density to mimic multicellular assembly conditions and epithelial-mesenchymal interactions in organogenesis. The bioengineered tooth germ generates a structurally correct tooth in vitro, and erupted successfully with correct tooth structure when transplanted into the oral cavity. We have ectopically generated a bioengineered tooth unit composed of a mature tooth, periodontal ligament and alveolar bone, and that tooth unit was engrafted into an adult jawbone through bone integration. Bioengineered teeth were also able to perform physiological tooth functions such as mastication, periodontal ligament function and response to noxious stimuli. In this review, we describe recent findings and technologies underpinning whole tooth regenerative therapy. PMID:26545754

  19. Molecular Genetics of Supernumerary Tooth Formation

    PubMed Central

    Wang, Xiu-Ping; Fan, Jiabing

    2011-01-01

    Summary Despite advances in the knowledge of tooth morphogenesis and differentiation, relatively little is known about the aetiology and molecular mechanisms underlying supernumerary tooth formation. A small number of supernumerary teeth may be a common developmental dental anomaly, while multiple supernumerary teeth usually have a genetic component and they are sometimes thought to represent a partial third dentition in humans. Mice, which are commonly used for studying tooth development, only exhibit one dentition, with very few mouse models exhibiting supernumerary teeth similar to those in humans. Inactivation of Apc or forced activation of Wnt/β(catenin signalling results in multiple supernumerary tooth formation in both humans and in mice, but the key genes in these pathways are not very clear. Analysis of other model systems with continuous tooth replacement or secondary tooth formation, such as fish, snake, lizard, and ferret, is providing insights into the molecular and cellular mechanisms underlying succesional tooth development, and will assist in the studies on supernumerary tooth formation in humans. This information, together with the advances in stem cell biology and tissue engineering, will pave ways for the tooth regeneration and tooth bioengineering. PMID:21309064

  20. Evaluation of peri-implant soft tissue and bone levels around early loaded implant in restoring single missing tooth: A clinico-radiographic study

    PubMed Central

    Bhardwaj, Isha; Bhushan, Anoop; Baiju, Chandrababu Sudha; Bali, Shweta; Joshi, Vaibhav

    2016-01-01

    Background: One-stage nonsubmerged protocol which can achieve success rates comparable to implants placed in a two-staged submerged procedure also the preconditions for periimplant bone regeneration has lead to more refined concepts of implant loading. Materials and Methods: Twenty sites with single missing tooth were included in this study. Clinical parameters included sulcus bleeding index (sBI), probing pocket depth (PD), and papilla index (PI) and radiographic parameters included crestal bone level were assessed for a period of 9 months. Results: The crestal bone loss showed mean value ranging from baseline 0.25 ± 0.11 to 0.31 ± 0.08 at 3 weeks, to 0.67 ± 0.13 at 3 months, to 0.85 ± 0.09 at 6 months, and to 0.88 ± 0.12 at 9 months. Probing PD, the mean value for probing PD at 3 weeks 1.20 ± 0.83, 3 months 1.60 ± 1.1, at 6 months 1.40 ± 1.14, and at 9 months 1.20 ± 1.0. sBI, mean value for sBI at 3 weeks 0.00 ± 0.00, 3 months 0.3 ± 0.11, at 6 months 0.09 ± 0.25, and at 9 months 0.08 ± 0.24. PI, showed a significant difference among at different points of time with P = 0.000. Conclusion: The dental implants showed <1 mm of crestal bone loss at 9 months follow-up, clinically significant marginal bone loss occurred between the time of implant placement and 3 months. Subsequent to that, bone loss observed around the implant up to 9 months was minimal. The periimplant soft tissue maturity was maintained throughout the study. PMID:27041836

  1. Investigation of EPR signals on tooth enamel

    NASA Astrophysics Data System (ADS)

    Pavlenko, A.; Mironova-Ulmane, N.; Polakov, M.; Riekstina, D.

    2007-12-01

    Calcified tissues are involved in continues metabolic process in human organism exchanging a number of chemical elements with environment. The rate of biochemical reactions is tissue dependent and the slowest one at the tooth enamel, the most mineralized tissue of human organism. The long time stability and unique chemical composition make tooth enamel suitable for number of application. The assessment of individual radiation dose by Electron Paramagnetic Resonance (EPR) and evaluations of elemental composition by Instrumentation Neutron Activation Analysis (INAA) are the well known procedures where properties of tooth enamel intensively used. The current work is focused on investigation of EPR signals and determination of chemical composition on several teeth samples having different origin. The EPR spectra and INAA element content of milk tooth, caries tooth, and paradantose tooth have been compared to each other. The results showed that the intensity of EPR signal is much higher for the caries tooth than the for paradantose tooth that is in agreement with depleted Ca content.

  2. Selective preparation of hard dental tissue: classical and laser treatments comparison

    NASA Astrophysics Data System (ADS)

    Dostálova, Tat'jana; Jelínkova, Helena; Němec, Michal; Koranda, Petr; Miyagi, Mitsunobu; Iwai, Katsumasa; Shi, Yi-Wei; Matsuura, Yuji

    2006-02-01

    For the purpose of micro-selective preparation which is part of the modern dentistry four various methods were examined: ablation by Er:YAG laser radiation (free-running or Q-switching regime), preparation of tissues by ultrasonic round ball tip, and by the classical dental drilling machine using diamond round bur. In the case of Er:YAG laser application the interaction energy 40 mJ in pulse of 200 us yielding to the interaction intensity 62 kW/cm2, and 20 mJ in pulse of 100 ns yielding to the interaction intensity 62 MW/cm2 was used for the case of free running, and Q-switch regime, respectively. For comparisson with the classical methods the ultrasound preparation tip (Sonixflex cariex TC, D - Sonicsys micro) and dental driller together with usual preparation burrs and standard handpiece were used. For the interaction experiment the samples of extracted human teeth and ebony cut into longitudinal sections and polished were used. The thickness of the prepared samples ranged from 5 to 7 mm. The methods were compared from the point of prepared cavity shape (SEM), inner surface, and possibility of selective removal of carries. The composite filling material was used to reconstruct the cavities. The dye penetrating analysis was performed.

  3. Influence of peak power in ablation rate of dental hard tissues: mathematical model

    NASA Astrophysics Data System (ADS)

    Colojoara, Carmen; Gabay, Shimon; van der Meulen, Freerk W.; van Gemert, Martin J. C.

    1996-12-01

    Pulsed Er:YAG and CO2 lasers should be suitable instruments for dentin and enamel ablation because both tissues have absorption peaks for radiation at 2.9 and 9.6 micrometers wavelengths. This is the context of our research that emphasizes the way in which the diameter and the depth of the crater made in enamel and dentin with the laser Er:YAG and CO2 is influenced in quantity and quality. Freshly extracted human third molar were used for this experiment. The laser source is Er:YAG Kavo Key dental model 1240 and CO2 Laser Sonics LS 860. The dimensions of the obtained craters were measured using the optical microscopy method. The obtained results were modelled experimentally with programs: GRAPHER and STATGRAPHICS. After the mathematical processing to the results what we obtain is relevant regarding the influence of the key parameters in the efficiency of the ablation according to the type of laser. On the whole, from our research results that both lasers ablate efficiently the dentin when the laser energy is between 200 and 300 mJ.

  4. Experimental comparison of grating- and propagation-based hard X-ray phase tomography of soft tissue

    NASA Astrophysics Data System (ADS)

    Lang, S.; Zanette, I.; Dominietto, M.; Langer, M.; Rack, A.; Schulz, G.; Le Duc, G.; David, C.; Mohr, J.; Pfeiffer, F.; Müller, B.; Weitkamp, T.

    2014-10-01

    When imaging soft tissues with hard X-rays, phase contrast is often preferred over conventional attenuation contrast due its superior sensitivity. However, it is unclear which of the numerous phase tomography methods yields the optimized results at given experimental conditions. Therefore, we quantitatively compared the three phase tomography methods implemented at the beamline ID19 of the European Synchrotron Radiation Facility: X-ray grating interferometry (XGI), and propagation-based phase tomography, i.e., single-distance phase retrieval (SDPR) and holotomography (HT), using cancerous tissue from a mouse model and an entire heart of a rat. We show that for both specimens, the spatial resolution derived from the characteristic morphological features is about a factor of two better for HT and SDPR compared to XGI, whereas the XGI data generally exhibit much better contrast-to-noise ratios for the anatomical features. Moreover, XGI excels in fidelity of the density measurements, and is also more robust against low-frequency artifacts than HT, but it might suffer from phase-wrapping artifacts. Thus, we can regard the three phase tomography methods discussed as complementary. The application will decide which spatial and density resolutions are desired, for the imaging task and dose requirements, and, in addition, the applicant must choose between the complexity of the experimental setup and the one of data processing.

  5. The effects of prostaglandin E2 in growing rats - Increased metaphyseal hard tissue and cortico-endosteal bone formation

    NASA Technical Reports Server (NTRS)

    Jee, W. S. S.; Ueno, K.; Deng, Y. P.; Woodbury, D. M.

    1985-01-01

    The role of in vivo prostaglandin E2 (PGE2) in bone formation is investigated. Twenty-five male Sprague-Dawley rats weighing between 223-267 g were injected subcutaneously with 0.3, 1.0, 3.0, and 6.0 mg of PGE2-kg daily for 21 days. The processing of the tibiae for observation is described. Radiographs and histomorphometric analyses are also utilized to study bone formation. Body weight, weights of soft tissues and bones morphometry are evaluated. It is observed that PGE2 depressed longitudinal bone growth, increased growth cartilage thickness, decreased degenerative cartilage cell size and cartilage cell production, and significantly increased proximal tibial metaphyseal hard tissue mass. The data reveal that periosteal bone formation is slowed down at higher doses of PGE2 and endosteal bone formation is slightly depressed less than 10 days post injection; however, here is a late increase (10 days after post injection) in endosteal bone formation and in the formation of trabecular bone in the marrow cavity of the tibial shaft. It is noted that the effects of PGE2 on bone formation are similar to the responses of weaning rats to PGE2.

  6. High-speed photographic studies of dye-assisted pulsed Nd:YAG laser ablation of dental hard tissues

    NASA Astrophysics Data System (ADS)

    Lu, Quiang; Wallace, David B.; Hayes, Donald J.

    1997-06-01

    We have been evaluating the use of a pulsed Nd:YAG laser for ablating hard dental tissue. For this application we apply dye-drops of an IR absorptive fluid on the enamel, then irradiate with a laser pulse from the laser. By using ink- jet technology to deliver the dye-drops, we can attain micron- and millisecond-scale precision in drop delivery, with a 'burst' of drops preceding each laser pulse. To gain better understanding of the ablation process we have used a high- speed CCD camera system with 1 microsecond(s) exposure and 1 microsecond(s) inter-exposure-interval capability. Fast photography of the ablation process showed the following typical events. (i) The laser induced plasma plume erupts immediately after pulse onset, expands to maximum within 50 microsecond(s) , and lasts up to 200 microsecond(s) . (ii) Ejected particles flying away from the site of laser pulse/dye-drop impact are detected within 30 microsecond(s) of laser pulse onset, and continue up to 10 ms. These particles attain velocities up to 50 m/s with lower velocities from lower pulse power. (iii) The plasma plume has a peak height that increases with increasing laser fluence, ranging up to 10 mm for a fluence of 242 J/cm2 on enamel. From this study, the dye-assisted ablation mechanisms are inferred to be plasma-mediated and explosion- mediated tissue removal.

  7. Experimental comparison of grating- and propagation-based hard X-ray phase tomography of soft tissue

    SciTech Connect

    Lang, S.; Schulz, G.; Müller, B.; Zanette, I.; Dominietto, M.; Langer, M.; Rack, A.; Le Duc, G.; David, C.; Mohr, J.; Pfeiffer, F.; Weitkamp, T.

    2014-10-21

    When imaging soft tissues with hard X-rays, phase contrast is often preferred over conventional attenuation contrast due its superior sensitivity. However, it is unclear which of the numerous phase tomography methods yields the optimized results at given experimental conditions. Therefore, we quantitatively compared the three phase tomography methods implemented at the beamline ID19 of the European Synchrotron Radiation Facility: X-ray grating interferometry (XGI), and propagation-based phase tomography, i.e., single-distance phase retrieval (SDPR) and holotomography (HT), using cancerous tissue from a mouse model and an entire heart of a rat. We show that for both specimens, the spatial resolution derived from the characteristic morphological features is about a factor of two better for HT and SDPR compared to XGI, whereas the XGI data generally exhibit much better contrast-to-noise ratios for the anatomical features. Moreover, XGI excels in fidelity of the density measurements, and is also more robust against low-frequency artifacts than HT, but it might suffer from phase-wrapping artifacts. Thus, we can regard the three phase tomography methods discussed as complementary. The application will decide which spatial and density resolutions are desired, for the imaging task and dose requirements, and, in addition, the applicant must choose between the complexity of the experimental setup and the one of data processing.

  8. Waveguide and articulated arm for Er:YAG laser system: shape and depth of laser cavity in hard dental tissues

    NASA Astrophysics Data System (ADS)

    Jelinkova, Helena; Dostalova, Tatjana; Miyagi, Mitsunobu; Wang, You; Shi, Yi-Wei; Dolezalova, Libuse; Hamal, Karel; Krejsa, Otakar; Kubelka, Jiri; Prochazka, Stanislav

    1998-04-01

    The aim of our study was to verify the efficiency of delivery systems for Er:YAG laser radiation which could be used in dentistry. The influence of increasing energy and number of pulses on a profile and depth of drilled holes was investigated. Er:YAG laser was operating in a free-running mode, generating a length of pulses 200 microsecond with a maximum energy of 500 mJ. The delivery systems investigated were an articulated arm and a fluorocarbon polymer-coated silver hollow glass waveguide. The prepared hard tissues were a sliced part of enamel, dentine and ivory. The laser radiation was directed on them by focusing optics (CaF2 lens) together with the cooling water to ensure that the tissues will not be burned. For the evaluation of shapes, depth and profiles of the prepared cavities the metallographic microscope, x-ray microtomograph and scanning electron microscope were used. From the results it was observed that the profile and depth of the cavities prepared by the laser radiation delivered by the various systems (waveguide or articulated arm) are not the same. The laser radiation delivered by waveguide produces a larger diameter cavity with a lower depth. The holes are smoother and without side effects.

  9. Laser ablation of human tooth

    NASA Astrophysics Data System (ADS)

    Franklin, Sushmita R.; Chauhan, P.; Mitra, A.; Thareja, R. K.

    2005-05-01

    We report the measurements of ablation threshold of human tooth in air using photo-thermal deflection technique. A third harmonic (355nm) of Nd:YAG (yttrium aluminum garnet) laser was used for irradiation and a low power helium neon laser as a probe beam. The experimental observations of ablation threshold in conjunction with theoretical model based on heat conduction equations for simulating the interaction of a laser radiation with a calcified tissue are used to estimate the absorption coefficient of human tooth.

  10. Eating with a saw for a jaw: functional morphology of the jaws and tooth-whorl in Helicoprion davisii.

    PubMed

    Ramsay, Jason B; Wilga, Cheryl D; Tapanila, Leif; Pruitt, Jesse; Pradel, Alan; Schlader, Robert; Didier, Dominique A

    2015-01-01

    The recent reexamination of a tooth-whorl fossil of Helicoprion containing intact jaws shows that the symphyseal tooth-whorl occupies the entire length of Meckel's cartilage. Here, we use the morphology of the jaws and tooth-whorl to reconstruct the jaw musculature and develop a biomechanical model of the feeding mechanism in these early Permian predators. The jaw muscles may have generated large bite-forces; however, the mechanics of the jaws and whorl suggest that Helicoprion was better equipped for feeding on soft-bodied prey. Hard shelled prey would tend to slip anteriorly from the closing jaws due to the curvature of the tooth-whorl, lack of cuspate teeth on the palatoquadrate (PQ), and resistance of the prey. When feeding on soft-bodied prey, deformation of the prey traps prey tissue between the two halves of the PQ and the whorl. The curvature of the tooth-whorl and position of the exposed teeth relative to the jaw joint results in multiple tooth functions from anterior to posterior tooth that aid in feeding on soft-bodied prey. Posterior teeth cut and push prey deeper into the oral cavity, while middle teeth pierce and cut, and anterior teeth hook and drag more of the prey into the mouth. Furthermore, the anterior-posterior edges of the teeth facilitate prey cutting with jaw closure and jaw depression. The paths traveled by each tooth during jaw depression are reminiscent of curved pathways used with slashing weaponry such as swords and knifes. Thus, the jaws and tooth-whorl may have formed a multifunctional tool for capturing, processing, and transporting prey by cyclic opening and closing of the lower jaw in a sawing fashion. PMID:25181366

  11. Tooth Wear Prevalence and Sample Size Determination : A Pilot Study

    PubMed Central

    Abd. Karim, Nama Bibi Saerah; Ismail, Noorliza Mastura; Naing, Lin; Ismail, Abdul Rashid

    2008-01-01

    Tooth wear is the non-carious loss of tooth tissue, which results from three processes namely attrition, erosion and abrasion. These can occur in isolation or simultaneously. Very mild tooth wear is a physiological effect of aging. This study aims to estimate the prevalence of tooth wear among 16-year old Malay school children and determine a feasible sample size for further study. Fifty-five subjects were examined clinically, followed by the completion of self-administered questionnaires. Questionnaires consisted of socio-demographic and associated variables for tooth wear obtained from the literature. The Smith and Knight tooth wear index was used to chart tooth wear. Other oral findings were recorded using the WHO criteria. A software programme was used to determine pathological tooth wear. About equal ratio of male to female were involved. It was found that 18.2% of subjects have no tooth wear, 63.6% had very mild tooth wear, 10.9% mild tooth wear, 5.5% moderate tooth wear and 1.8 % severe tooth wear. In conclusion 18.2% of subjects were deemed to have pathological tooth wear (mild, moderate & severe). Exploration with all associated variables gave a sample size ranging from 560 – 1715. The final sample size for further study greatly depends on available time and resources. PMID:22589636

  12. Precise ablation of dental hard tissues with ultra-short pulsed lasers. Preliminary exploratory investigation on adequate laser parameters.

    PubMed

    Bello-Silva, Marina Stella; Wehner, Martin; Eduardo, Carlos de Paula; Lampert, Friedrich; Poprawe, Reinhart; Hermans, Martin; Esteves-Oliveira, Marcella

    2013-01-01

    This study aimed to evaluate the possibility of introducing ultra-short pulsed lasers (USPL) in restorative dentistry by maintaining the well-known benefits of lasers for caries removal, but also overcoming disadvantages, such as thermal damage of irradiated substrate. USPL ablation of dental hard tissues was investigated in two phases. Phase 1--different wavelengths (355, 532, 1,045, and 1,064 nm), pulse durations (picoseconds and femtoseconds) and irradiation parameters (scanning speed, output power, and pulse repetition rate) were assessed for enamel and dentin. Ablation rate was determined, and the temperature increase measured in real time. Phase 2--the most favorable laser parameters were evaluated to correlate temperature increase to ablation rate and ablation efficiency. The influence of cooling methods (air, air-water spray) on ablation process was further analyzed. All parameters tested provided precise and selective tissue ablation. For all lasers, faster scanning speeds resulted in better interaction and reduced temperature increase. The most adequate results were observed for the 1064-nm ps-laser and the 1045-nm fs-laser. Forced cooling caused moderate changes in temperature increase, but reduced ablation, being considered unnecessary during irradiation with USPL. For dentin, the correlation between temperature increase and ablation efficiency was satisfactory for both pulse durations, while for enamel, the best correlation was observed for fs-laser, independently of the power used. USPL may be suitable for cavity preparation in dentin and enamel, since effective ablation and low temperature increase were observed. If adequate laser parameters are selected, this technique seems to be promising for promoting the laser-assisted, minimally invasive approach. PMID:22565342

  13. Comparison of CT-Number and Gray Scale Value of Different Dental Materials and Hard Tissues in CT and CBCT

    PubMed Central

    Emadi, Naghmeh; Safi, Yaser; Akbarzadeh Bagheban, Alireza; Asgary, Saeed

    2014-01-01

    Introduction: Computed tomography (CT) and cone-beam CT (CBCT) are valuable diagnostic aids for many clinical applications. This study was designed to compare the gray scale value (GSV) and Hounsfield unit (HU) of selected dental materials and various hard tissues using CT or CBCT. Methods and Materials: Three samples of all test materials including amalgam (AM), composite resin (CR), glass ionomer (GI), zinc-oxide eugenol (ZOE), calcium-enriched mixture (CEM) cement, AH-26 root canal sealer (AH-26), gutta-percha (GP), Coltosol (Col), Dycal (DL), mineral trioxide aggregate (MTA), zinc phosphate (ZP), and polycarbonate cement (PC) were prepared and scanned together with samples of bone, dentin and enamel using two CBCT devices, Scanora 3D (S3D) and NewTom VGi (NTV) and a spiral CT (SCT) scanner (Somatom Emotion 16 multislice spiral CT);. Subsequently, the HU and GSV values were determined and evaluated. The data were analyzed by the Kruskal-Wallis and Mann-Whitney U tests. The level of significance was determined at 0.05. Results: There were significant differences among the three different scanners (P<0.05). The differences between HU/GSV values of 12 selected dental materials using NTV was significant (P<0.05) and for S3D and SCT was insignificant (P>0.05). All tested materials showed maximum values in S3D and SCT (3094 and 3071, respectively); however, bone and dentin showed low/medium values (P<0.05). In contrast, the tested materials and tissues showed a range of values in NTV (366 to15383; P<0.05). Conclusion: Scanner system can influence the obtained HU/GSV of dental materials. NTV can discriminate various dental materials, in contrast to S3D/SCT scanners. NTV may be a more useful diagnostic aid for clinical practice. PMID:25386210

  14. Hard-tissue drilling by short-pulse CO2 laser with controllable pulse-tail energy

    NASA Astrophysics Data System (ADS)

    Uno, Kazuyuki; Sasaki, Tatsufumi; Yamamoto, Takuya; Akitsu, Tetsuya; Jitsuno, Takahisa

    2016-02-01

    We developed a longitudinally excited CO2 laser that produces a short laser pulse with the almost same spike-pulse energy of about 0.8 mJ and the controllable pulse-tail energy of 0-21.26 mJ. The laser was very simple and consisted of a 45-cm-long alumina ceramic pipe with an inner diameter of 9 mm, a pulse power supply, a step-up transformer, a storage capacitance and a spark-gap switch. In single-shot irradiation using these laser pulses, the dependence of the drilling depth of dry ivory samples on the fluence was investigated. The drilling depth increased with the fluence in the same laser pulse waveform. In this work, the effective short laser pulse for the hard tissue drilling was the laser pulse with the spike pulse energy of 0.87 mJ and the pulse tail energy of 6.33 mJ that produced the drilling depth of 28.1 μm at the fluence of 3.48 J/cm2 and the drilling depth per the fluence of 7.27 μm/J/cm2.

  15. β-type Ti-10Mo-1.25Si-xZr biomaterials for applications in hard tissue replacements.

    PubMed

    Zhan, Yongzhong; Li, Chunliu; Jiang, Wenping

    2012-08-01

    In order to develop new β-type Ti-based biochemical materials, a series of Ti-10Mo-1.25Si-xZr (x=4-13) alloys were designed and prepared using vacuum arc melting method. Phase analysis and microstructural observation showed that all the as cast samples consisted of equiaxed β-Ti phase. With the increase of Zr content, the structure of grain boundary changed from semi-continuous network to denser granular, and the microstructure was refined. The solid solution effect of the β-phase stabilization elements (i.e. Mo, Zr and Si) predominantly determined the mechanical properties. These β-type Ti-10Mo-1.25Si-xZr biomaterials exhibited a good combination of high compressive strength, high yield stress, good plasticity, as well as rather low Young's modulus (in the range of 23.086 GPa-32.623 GPa), which may offer potential advantages in the applications in hard tissue replacements (HTRs). PMID:24364974

  16. Tooth - abnormal colors

    MedlinePlus

    ... appear as spots or lines in the tooth enamel. Your genes affect your tooth color. Other things ... Infections Inherited diseases may affect the thickness of enamel or the calcium or protein content of the ...

  17. Overview of Tooth Disorders

    MedlinePlus

    ... as when chewing or when tapped by a dental instrument. Pain in a tooth suggests tooth decay or gum ... fractured. Sinus congestion can cause similar symptoms of pain in the area of the upper ... CONSUMERS: ...

  18. Ion channels, channelopathies, and tooth formation.

    PubMed

    Duan, X

    2014-02-01

    The biological functions of ion channels in tooth development vary according to the nature of their gating, the species of ions passing through those gates, the number of gates, localization of channels, tissue expressing the channel, and interactions between cells and microenvironment. Ion channels feature unique and specific ion flux in ameloblasts, odontoblasts, and other tooth-specific cell lineages. Both enamel and dentin have active chemical systems orchestrating a variety of ion exchanges and demineralization and remineralization processes in a stage-dependent manner. An important role for ion channels is to regulate and maintain the calcium and pH homeostasis that are critical for proper enamel and dentin biomineralization. Specific functions of chloride channels, TRPVs, calcium channels, potassium channels, and solute carrier superfamily members in tooth formation have been gradually clarified in recent years. Mutations in these ion channels or transporters often result in disastrous changes in tooth development. The channelopathies of tooth include altered eruption (CLCN7, KCNJ2, TRPV3), root dysplasia (CLCN7, KCNJ2), amelogenesis imperfecta (KCNJ1, CFTR, AE2, CACNA1C, GJA1), dentin dysplasia (CLCN5), small teeth (CACNA1C, GJA1), tooth agenesis (CLCN7), and other impairments. The mechanisms leading to tooth channelopathies are primarily related to pH regulation, calcium homeostasis, or other alterations of the niche for tooth eruption and development. PMID:24076519

  19. Mössbauer Studies of Stannous Fluoride Reactivity with Synthetic Tooth Enamel - A Model for the Tooth Cavity Protection Actions of Novel Dentifrices

    NASA Astrophysics Data System (ADS)

    Dénès, Georges; Muntasar, Abdualhafeed; Kozak, Kathy M.; Baig, Arif A.; White, Donald J.

    2002-06-01

    SnF2 is an important toothpaste ingredient, added for the provision of clinical efficacy for hard and soft tissue diseases and in breath protection. Synthetic calcium hydroxyapatite powders were exposed to liquid supernates (25 w/w% toothpaste water slurries, centrifuged) of Crest Gum Care® (SnF2) dentifrice. One-minute treatments were followed by 3x water washing, centrifugation and lyophilization. Post treatment, powders were analyzed by Mössbauer spectroscopy with 0.5-1 gram of treated apatite powder. Results show that tooth mineral stannous fluoride interactions include: (1) formation of surface reaction products with both Sn(II) and Sn(IV) oxidation states; (2) Sn-F binding on mineral surfaces with no evidence of SnO. The surface binding is, however, not pure Sn-F but contains contributions of other ligands, probably oxygens from surface phosphates or hydroxyl groups. Results also suggest that surface reacted stannous tin is oxidized with time, even when bound as a layer on the tooth surface. This study demonstrates for the first time the presence of Sn-F on tooth enamel post treatment and the contribution of passivation to long term stannous chemistry on tooth surfaces. The study also illustrates the practical applications of the Mössbauer technique.

  20. Fractured tooth (image)

    MedlinePlus

    A tooth can be chipped or fractured during an accident or a bad fall. A tooth that is chipped or not badly fractured can usually be handled on a nonemergency basis. A tooth that is badly fractured may have exposed nerve ...

  1. Supplemental tooth in primary dentition

    PubMed Central

    Mohan, Ravi Prakash Sasankoti; Verma, Sankalp; Singh, Udita; Agarwal, Neha

    2014-01-01

    An extra tooth causing numerical excess in dentition is described as supernumerary tooth, and the resultant condition is termed as hyperdontia. Hyperdontia is more commonly seen in the permanent dentition than primary one. Supernumerary tooth which resembles tooth shape and supplements for occlusion is called as supplemental tooth. We present a case with supplemental tooth in primary dentition. PMID:24913075

  2. Industrial Noise and Tooth Wear - Experimental Study

    PubMed Central

    Cavacas, Maria Alzira; Tavares, Vitor; Borrecho, Gonçalo; Oliveira, Maria João; Oliveira, Pedro; Brito, José; Águas, Artur; dos Santos, José Martins

    2015-01-01

    Tooth wear is a complex multifactorial process that involves the loss of hard dental tissue. Parafunctional habits have been mentioned as a self-destructive process caused by stress, which results in hyperactivity of masticatory muscles. Stress manifests itself through teeth grinding, leading to progressive teeth wear. The effects of continuous exposure to industrial noise, a “stressor” agent, cannot be ignored and its effects on the teeth must be evaluated. Aims: The aim of this study was to ascertain the effects of industrial noise on dental wear over time, by identifying and quantifying crown area loss. Material and Methods: 39 Wistar rats were used. Thirty rats were divided in 3 experimental groups of 10 animals each. Animals were exposed to industrial noise, rich in LFN components, for 1, 4 and 7 months, with an average weekly exposure of 40 hours (8h/day, 5 days/week with the weekends in silence). The remaining 9 animals were kept in silence. The areas of the three main cusps of the molars were measured under light microscopy. Statistical analysis used: A two-way ANOVA model was applied at significance level of 5%. Results: The average area of the molar cusps was significantly different between exposed and non-exposed animals. The most remarkable differences occurred between month 1 and 4. The total crown loss from month 1 to month 7 was 17.3% in the control group, and 46.5% in the exposed group, and the differences between these variations were significant (p<0.001). Conclusions: Our data suggest that industrial noise is an important factor in the pathogenesis of tooth wear. PMID:25798052

  3. Evaluation of soft and hard tissue changes after bimaxillary surgery in class III orthognathic surgery and aesthetic consideration

    PubMed Central

    Ghassemi, Mehrangiz; Ghassemi, Alireza; Showkatbakhsh, Rahman; Ahmad, Syed Sayeed; Shadab, Mohammad; Modabber, Ali; Jamilian, Abdolreza

    2014-01-01

    Aims: The aim of this study was to evaluate hard and soft tissue change after bimaxillary surgery in class III patients by focusing on sella, nasion, A point (SNA) and sella, nasion, B point (SNB) angle and aesthetic outcome. Materials and Methods: The sample consisted of 96 skeletal Class III patients (42 women, 54 men) with a mean age of 25 years with standard deviation (SD) of 8.4. The youngest patient was 16-years-old and the oldest 51-years-old at the time of surgery. In total, seven skeletal parameters, eight soft tissue parameters, and two dental parameters were evaluated on the cephalograms. Result: At the beginning of the treatment 49 Patients had SNA between 80° and 84°, 34 had SNA of less than 80° and 13 had SNA of more than 84°. Post surgically, 25 patients had SNA of 78°–84°, 19 had SNA less than 78° and 52 patients had SNA of more than 84°. Out of 96 patients 22 had SNB of 78°–82° before surgery, 16 had less than 78° and 58 had SNA of more than 84°. Postoperatively, we measured SNB of 78°–80° in 42, less than 78° in 18 and of more than 82° in 36 patients. The inclination of the maxilla relative to the cranial base changed from 7.2° (SD = 4)–8° (SD = 5.1) and the mandible changed from 35.7° (SD = 6.6) to 36° (SD = 6.3) postoperatively which was not significant. The distance from upper lip to E-line increased by 2.6 mm (SD = 3.9) after surgery (P < 0.001), while, the lower lip distance to E-line decreased slightly by 0.9 mm (SD = 3.2) (P < 0.01). Nasolabial angle was decreased by 9.5° (SD = 9.4) after surgery (P < 0.001). The nose prominence also decreased from 18.2 mm (SD = 3.5) –16.5 mm (SD = 3.3). Conclusion: Although in many cases we did not have a SNA angle or SNB angle in normal range but a good aesthetic outcome have been observed. Consequently our study showed that soft tissue change and aesthetic aspects should be considered in surgical planning and achieving SNA angle or SNB angle of norm range should not be the

  4. Dental cell sheet biomimetic tooth bud model.

    PubMed

    Monteiro, Nelson; Smith, Elizabeth E; Angstadt, Shantel; Zhang, Weibo; Khademhosseini, Ali; Yelick, Pamela C

    2016-11-01

    Tissue engineering and regenerative medicine technologies offer promising therapies for both medicine and dentistry. Our long-term goal is to create functional biomimetic tooth buds for eventual tooth replacement in humans. Here, our objective was to create a biomimetic 3D tooth bud model consisting of dental epithelial (DE) - dental mesenchymal (DM) cell sheets (CSs) combined with biomimetic enamel organ and pulp organ layers created using GelMA hydrogels. Pig DE or DM cells seeded on temperature-responsive plates at various cell densities (0.02, 0.114 and 0.228 cells 10(6)/cm(2)) and cultured for 7, 14 and 21 days were used to generate DE and DM cell sheets, respectively. Dental CSs were combined with GelMA encapsulated DE and DM cell layers to form bioengineered 3D tooth buds. Biomimetic 3D tooth bud constructs were cultured in vitro, or implanted in vivo for 3 weeks. Analyses were performed using micro-CT, H&E staining, polarized light (Pol) microscopy, immunofluorescent (IF) and immunohistochemical (IHC) analyses. H&E, IHC and IF analyses showed that in vitro cultured multilayered DE-DM CSs expressed appropriate tooth marker expression patterns including SHH, BMP2, RUNX2, tenascin and syndecan, which normally direct DE-DM interactions, DM cell condensation, and dental cell differentiation. In vivo implanted 3D tooth bud constructs exhibited mineralized tissue formation of specified size and shape, and SHH, BMP2 and RUNX2and dental cell differentiation marker expression. We propose our biomimetic 3D tooth buds as models to study optimized DE-DM cell interactions leading to functional biomimetic replacement tooth formation. PMID:27565550

  5. Probable biofilm formation in the cheek as a complication of soft tissue filler resulting from improper endodontic treatment of tooth 16.

    PubMed

    Marusza, Wojciech; Mlynarczyk, Grazyna; Olszanski, Romuald; Netsvyetayeva, Irina; Obrowski, Michael; Iannitti, Tommaso; Palmieri, Beniamino

    2012-01-01

    Injectable filling agents offer the promise of a better appearance without surgery and, among them, hyaluronic acid is the most commonly used. Although complications are rare, it is necessary to know the possible side effects and complications in order to be prepared for their management. That is why many researchers have been focusing on the interactions between hyaluronic acid and pathogens, inflammatory mediators, the immune system, and markers of oxidative stress to achieve efficient drug delivery, given that hyaluronic acid has widening applications in the field of nanomedicine. Here we report the case of a 37-year-old female patient who returned to our clinic with an abscess in her left cheek 3 months after a deep injection of 1 mL of stabilized hyaluronic acid in both cheeks. Steroid and antibiotic therapy was initiated without success, and abscess drainage was performed. Extraction of tooth 16 was performed 11 days after insertion of drains into the abscess. Laboratory blood tests showed acute inflammation of presumed bacterial etiology. Microbiological examination of pus was negative. Bacterial cultures were found in the extracted tooth. After antibiotic therapy, a complete reversal of the pathological process was observed. The present report highlights the need to assess periodontal problems prior to any aesthetic facial treatment. Analyses of further case reports and clinical studies are necessary to understand the potential role of hyaluronic acid in the formation of biofilm, and how to avoid this complication, thereby increasing the safety of hyaluronic acid-based procedures. PMID:22619504

  6. Probable biofilm formation in the cheek as a complication of soft tissue filler resulting from improper endodontic treatment of tooth 16

    PubMed Central

    Marusza, Wojciech; Mlynarczyk, Grazyna; Olszanski, Romuald; Netsvyetayeva, Irina; Obrowski, Michael; Iannitti, Tommaso; Palmieri, Beniamino

    2012-01-01

    Injectable filling agents offer the promise of a better appearance without surgery and, among them, hyaluronic acid is the most commonly used. Although complications are rare, it is necessary to know the possible side effects and complications in order to be prepared for their management. That is why many researchers have been focusing on the interactions between hyaluronic acid and pathogens, inflammatory mediators, the immune system, and markers of oxidative stress to achieve efficient drug delivery, given that hyaluronic acid has widening applications in the field of nanomedicine. Here we report the case of a 37-year-old female patient who returned to our clinic with an abscess in her left cheek 3 months after a deep injection of 1 mL of stabilized hyaluronic acid in both cheeks. Steroid and antibiotic therapy was initiated without success, and abscess drainage was performed. Extraction of tooth 16 was performed 11 days after insertion of drains into the abscess. Laboratory blood tests showed acute inflammation of presumed bacterial etiology. Microbiological examination of pus was negative. Bacterial cultures were found in the extracted tooth. After antibiotic therapy, a complete reversal of the pathological process was observed. The present report highlights the need to assess periodontal problems prior to any aesthetic facial treatment. Analyses of further case reports and clinical studies are necessary to understand the potential role of hyaluronic acid in the formation of biofilm, and how to avoid this complication, thereby increasing the safety of hyaluronic acid-based procedures. PMID:22619504

  7. Giant panda׳s tooth enamel: Structure, mechanical behavior and toughening mechanisms under indentation.

    PubMed

    Weng, Z Y; Liu, Z Q; Ritchie, R O; Jiao, D; Li, D S; Wu, H L; Deng, L H; Zhang, Z F

    2016-12-01

    The giant panda׳s teeth possess remarkable load-bearing capacity and damage resistance for masticating bamboos. In this study, the hierarchical structure and mechanical behavior of the giant panda׳s tooth enamel were investigated under indentation. The effects of loading orientation and location on mechanical properties of the enamel were clarified and the evolution of damage in the enamel under increasing load evaluated. The nature of the damage, both at and beneath the indentation surfaces, and the underlying toughening mechanisms were explored. Indentation cracks invariably were seen to propagate along the internal interfaces, specifically the sheaths between enamel rods, and multiple extrinsic toughening mechanisms, e.g., crack deflection/twisting and uncracked-ligament bridging, were active to shield the tips of cracks from the applied stress. The giant panda׳s tooth enamel is analogous to human enamel in its mechanical properties, yet it has superior hardness and Young׳s modulus but inferior toughness as compared to the bamboo that pandas primarily feed on, highlighting the critical roles of the integration of underlying tissues in the entire tooth and the highly hydrated state of bamboo foods. Our objective is that this study can aid the understanding of the structure-mechanical property relations in the tooth enamel of mammals and further provide some insight on the food habits of the giant pandas. PMID:27498423

  8. Tooth Germ-Like Construct Transplantation for Whole-Tooth Regeneration: An In Vivo Study in the Miniature Pig.

    PubMed

    Yang, Kai-Chiang; Kitamura, Yutaka; Wu, Chang-Chin; Chang, Hao-Hueng; Ling, Thai-Yen; Kuo, Tzong-Fu

    2016-04-01

    The purpose of this study was to demonstrate the feasibility of whole-tooth regeneration using a tooth germ-like construct. Dental pulp from upper incisors, canines, premolars, and molars were extracted from sexually mature miniature pigs. Pulp tissues were cultured and expanded in vitro to obtain dental pulp stem cells (DPSCs), and cells were differentiated into odontoblasts and osteoblasts. Epithelial cells were isolated from gingival epithelium. The epithelial cells, odontoblasts, and osteoblasts were seeded onto the surface, upper, and lower layers, respectively, of a bioactive scaffold. The lower first and second molar tooth germs were removed bilaterally and the layered cell/scaffold constructs were transplanted to the mandibular alveolar socket of a pig. At 13.5 months postimplantation, seven of eight pigs developed two teeth with crown, root, and pulp structures. Enamel-like tissues, dentin, cementum, odontoblasts, and periodontal tissues were found upon histological inspection. The regenerated tooth expressed dentin matrix protein-1 and osteopontin. All pigs had regenerated molar teeth regardless of the original tooth used to procure the DPSCs. Pigs that had tooth germs removed or who received empty scaffolds did not develop teeth. Although periodontal ligaments were generated, ankylosis was found in some animals. This study revealed that implantation of a tooth germ-like structure generated a complete tooth with a high success rate. The implant location may influence the morphology of the regenerated tooth. PMID:26582651

  9. Interrelationships between tooth properties and biochemical bone turnover markers investigated on six-month-old pig model.

    PubMed

    Tymczyna, Barbara; Tatara, Marcin R; Krupski, Witold; Tymczyna-Sobotka, Monika; Bachanek, Teresa

    2013-01-01

    The aim of the study was to determine interrelationships between bone tissue metabolism indices and morphological, biomechanical and densitometric properties of hard dental tissues. First primary maxillary incisor from 6-month-old pigs (N=27) was evaluated in terms of weight and length. Mean volumetric tooth mineral density, total tooth volume, enamel total volume, enamel volumetric mineral density, dentine total volume and dentine volumetric mineral density were estimated with the use of quantitative computed tomography and micro computed tomography techniques. Tooth mineral density and tooth mineral content were evaluated with the use of dual-energy X-ray absorptiometry. Microhardness of enamel was measured using Vicker's test. Evaluations of total calcium, ionized calcium, magnesium, phosphorus, alkaline phosphatase, bone alkaline phosphatase, osteocalcin, C-terminal telopeptide of type-I collagen (CTX), insulin-like growth factor-1, growth hormone and parathyroid hormone were performed in plasma and serum samples. Pearson's correlation coefficients were determined between all the investigated variables, and P<0.05 was considered as statistically significant. The obtained results have shown mainly mutual dependences between biochemical indicators of bone metabolism. Evaluation of CTX concentration in serum of pigs has shown the highest predictive value in relation to morphological, densitometric and biomechanical properties of teeth. PMID:23076035

  10. Tooth formation - delayed or absent

    MedlinePlus

    Delayed or absent tooth formation; Teeth - delayed or absent formation ... The age at which the tooth comes in varies. Most infants get their first tooth between 6 and 9 months, but it may be earlier or later. ...

  11. Human tooth and root canal morphology reconstruction using magnetic resonance imaging

    PubMed Central

    DRĂGAN, OANA CARMEN; FĂRCĂŞANU, ALEXANDRU ŞTEFAN; CÂMPIAN, RADU SEPTIMIU; TURCU, ROMULUS VALERIU FLAVIU

    2016-01-01

    Background and aims Visualization of the internal and external root canal morphology is very important for a successful endodontic treatment; however, it seems to be difficult considering the small size of the tooth and the complexity of the root canal system. Film-based or digital conventional radiographic techniques as well as cone beam computed tomography provide limited information on the dental pulp anatomy or have harmful effects. A new non-invasive diagnosis tool is magnetic resonance imaging, due to its ability of imaging both hard and soft tissues. The aim of this study was to demonstrate magnetic resonance imaging to be a useful tool for imaging the anatomic conditions of the external and internal root canal morphology for endodontic purposes. Methods The endodontic system of one freshly extracted wisdom tooth, chosen for its well-known anatomical variations, was mechanically shaped using a hybrid technique. After its preparation, the tooth was immersed into a recipient with saline solution and magnetic resonance imaged immediately. A Bruker Biospec magnetic resonance imaging scanner operated at 7.04 Tesla and based on Avance III radio frequency technology was used. InVesalius software was employed for the 3D reconstruction of the tooth scanned volume. Results The current ex-vivo experiment shows the accurate 3D volume rendered reconstruction of the internal and external morphology of a human extracted and endodontically treated tooth using a dataset of images acquired by magnetic resonance imaging. The external lingual and vestibular views of the tooth as well as the occlusal view of the pulp chamber, the access cavity, the distal canal opening on the pulp chamber floor, the coronal third of the root canals, the degree of root separation and the apical fusion of the two mesial roots, details of the apical region, root canal curvatures, furcal region and interradicular root grooves could be clearly bordered. Conclusions Magnetic resonance imaging offers 3

  12. [Tooth-pick? Picking the Right Tooth].

    PubMed

    Apicella, Lysann; Cassis, Paola Rodoni; Balestra, Brenno

    2016-01-20

    We report about an 80-year-old patient, who underwent the extraction of an upper molar tooth because of facial pain. In the course of time the patient developed a maxillary sinusitis in presence of an ectopic tooth. Given that the patient got fever, neck pain and -stiffness, a purulent meningitis was first suspected. The liquor analysis was normal and the CT-scan showed a calcification around the dens axis. We finally diagnosed a “Crowned Dens”-syndrome. PMID:26787332

  13. Human walking isn't all hard work: evidence of soft tissue contributions to energy dissipation and return

    PubMed Central

    Zelik, Karl E.; Kuo, Arthur D.

    2010-01-01

    The muscles and tendons of the lower extremity are generally considered the dominant producers of positive and negative work during gait. However, soft-tissue deformations not captured by joint rotations might also dissipate, store and even return substantial energy to the body. A key locomotion event is the collision of the leg with the ground, which deforms soft tissues appreciably in running. Significant deformation might also result from the impulsive ground collision in walking. In a study of normal human walking (N=10; 0.7–2.0 m s–1 speeds), we show indirect evidence for both negative and positive work performed by soft tissue, consistent with a damped elastic collision and rebound. We used the difference between measured joint work and another quantity – the work performed on the body center of mass – to indicate possible work performed by soft tissue. At 1.25 m s–1, we estimated that soft tissue performs approximately 7.5 J of negative work per collision. This constitutes approximately 60% of the total negative collision work and 31% of the total negative work per stride. The amount of soft tissue work during collision increases sharply with speed. Each collision is followed by 4 J of soft tissue rebound that is also not captured by joint work measures. Soft tissue deformation may save muscles the effort of actively dissipating energy, and soft tissue elastic rebound could save up to 14% of the total positive work per stride. Soft tissues not only cushion impacts but also appear to perform substantial work. PMID:21113007

  14. Mechanical modelling of tooth wear.

    PubMed

    Karme, Aleksis; Rannikko, Janina; Kallonen, Aki; Clauss, Marcus; Fortelius, Mikael

    2016-07-01

    Different diets wear teeth in different ways and generate distinguishable wear and microwear patterns that have long been the basis of palaeodiet reconstructions. Little experimental research has been performed to study them together. Here, we show that an artificial mechanical masticator, a chewing machine, occluding real horse teeth in continuous simulated chewing (of 100 000 chewing cycles) is capable of replicating microscopic wear features and gross wear on teeth that resemble wear in specimens collected from nature. Simulating pure attrition (chewing without food) and four plant material diets of different abrasives content (at n = 5 tooth pairs per group), we detected differences in microscopic wear features by stereomicroscopy of the chewing surface in the number and quality of pits and scratches that were not always as expected. Using computed tomography scanning in one tooth per diet, absolute wear was quantified as the mean height change after the simulated chewing. Absolute wear increased with diet abrasiveness, originating from phytoliths and grit. In combination, our findings highlight that differences in actual dental tissue loss can occur at similar microwear patterns, cautioning against a direct transformation of microwear results into predictions about diet or tooth wear rate. PMID:27411727

  15. Cracked tooth syndrome: Overview of literature.

    PubMed

    Hasan, Shamimul; Singh, Kuldeep; Salati, Naseer

    2015-01-01

    Pain is defined as an "unpleasant sensory and emotional feeling which is associated with actual or potential injury of tissue or expressed in terms of such injury." Tooth pain usually refers to pain around the teeth or jaws mainly as a result of a dental condition. Mostly, toothaches are caused by a carious cavity, a broken tooth, an exposed tooth root or gum disease. The toothache may sometimes be the result of radiating pain from structures in the vicinity of tooth and jaws (cardiac pain, ear, nose, throat pain, and sinusitis). Therefore, evaluation by both dentists and physicians are sometimes necessary to diagnose medical illnesses causing "toothache." Cracked tooth syndrome is a major diagnostic challenge in clinical practice. Accurate diagnosis and appropriate treatment are complicated due to lack of awareness of this condition and its bizarre clinical features. Early diagnosis has been linked with successful restorative management and good prognosis. This article provides a detailed literature on the causes, classification, signs and symptoms, diagnosis, and treatment planning of cracked tooth syndrome. PMID:26539363

  16. Cracked tooth syndrome: Overview of literature

    PubMed Central

    Hasan, Shamimul; Singh, Kuldeep; Salati, Naseer

    2015-01-01

    Pain is defined as an “unpleasant sensory and emotional feeling which is associated with actual or potential injury of tissue or expressed in terms of such injury.” Tooth pain usually refers to pain around the teeth or jaws mainly as a result of a dental condition. Mostly, toothaches are caused by a carious cavity, a broken tooth, an exposed tooth root or gum disease. The toothache may sometimes be the result of radiating pain from structures in the vicinity of tooth and jaws (cardiac pain, ear, nose, throat pain, and sinusitis). Therefore, evaluation by both dentists and physicians are sometimes necessary to diagnose medical illnesses causing “toothache.” Cracked tooth syndrome is a major diagnostic challenge in clinical practice. Accurate diagnosis and appropriate treatment are complicated due to lack of awareness of this condition and its bizarre clinical features. Early diagnosis has been linked with successful restorative management and good prognosis. This article provides a detailed literature on the causes, classification, signs and symptoms, diagnosis, and treatment planning of cracked tooth syndrome. PMID:26539363

  17. Digital dissection - using contrast-enhanced computed tomography scanning to elucidate hard- and soft-tissue anatomy in the Common Buzzard Buteo buteo.

    PubMed

    Lautenschlager, Stephan; Bright, Jen A; Rayfield, Emily J

    2014-04-01

    Gross dissection has a long history as a tool for the study of human or animal soft- and hard-tissue anatomy. However, apart from being a time-consuming and invasive method, dissection is often unsuitable for very small specimens and often cannot capture spatial relationships of the individual soft-tissue structures. The handful of comprehensive studies on avian anatomy using traditional dissection techniques focus nearly exclusively on domestic birds, whereas raptorial birds, and in particular their cranial soft tissues, are essentially absent from the literature. Here, we digitally dissect, identify, and document the soft-tissue anatomy of the Common Buzzard (Buteo buteo) in detail, using the new approach of contrast-enhanced computed tomography using Lugol's iodine. The architecture of different muscle systems (adductor, depressor, ocular, hyoid, neck musculature), neurovascular, and other soft-tissue structures is three-dimensionally visualised and described in unprecedented detail. The three-dimensional model is further presented as an interactive PDF to facilitate the dissemination and accessibility of anatomical data. Due to the digital nature of the data derived from the computed tomography scanning and segmentation processes, these methods hold the potential for further computational analyses beyond descriptive and illustrative proposes. PMID:24350638

  18. Digital dissection – using contrast-enhanced computed tomography scanning to elucidate hard-and soft-tissue anatomy in the Common Buzzard Buteo buteo

    PubMed Central

    Lautenschlager, Stephan; Bright, Jen A; Rayfield, Emily J

    2014-01-01

    Gross dissection has a long history as a tool for the study of human or animal soft-and hard-tissue anatomy. However, apart from being a time-consuming and invasive method, dissection is often unsuitable for very small specimens and often cannot capture spatial relationships of the individual soft-tissue structures. The handful of comprehensive studies on avian anatomy using traditional dissection techniques focus nearly exclusively on domestic birds, whereas raptorial birds, and in particular their cranial soft tissues, are essentially absent from the literature. Here, we digitally dissect, identify, and document the soft-tissue anatomy of the Common Buzzard (Buteo buteo) in detail, using the new approach of contrast-enhanced computed tomography using Lugol's iodine. The architecture of different muscle systems (adductor, depressor, ocular, hyoid, neck musculature), neurovascular, and other soft-tissue structures is three-dimensionally visualised and described in unprecedented detail. The three-dimensional model is further presented as an interactive PDF to facilitate the dissemination and accessibility of anatomical data. Due to the digital nature of the data derived from the computed tomography scanning and segmentation processes, these methods hold the potential for further computational analyses beyond descriptive and illustrative proposes. PMID:24350638

  19. Interactions of the tooth and bone during development.

    PubMed

    Alfaqeeh, S A; Gaete, M; Tucker, A S

    2013-12-01

    The tooth works as a functional unit with its surrounding bony socket, the alveolar bone. The growth of the tooth and alveolar bone is co-ordinated so that a studied distance always separates the 2, known as the tooth-bone interface (TBI). Lack of mineralization, a crucial feature of the TBI, creates the space for the developing tooth to grow and the soft tissues of the periodontium to develop. We have investigated the interactions between the tooth and its surrounding bone during development, focusing on the impact of the developing alveolar bone on the development of the mouse first molar (M1). During development, TRAP-positive osteoclasts are found to line the TBI as bone starts to be deposited around the tooth, removing the bone as the tooth expands. An enhancement of osteoclastogenesis through RANK-RANKL signaling results in an expansion of the TBI, showing that osteoclasts are essential for defining the size of this region. Isolation of the M1 from the surrounding mesenchyme and alveolar bone leads to an expansion of the tooth germ, driven by increased proliferation, indicating that, during normal development, the growth of the tooth germ is constrained by the surrounding tissues. PMID:24155263

  20. The tissue diagnostic instrument

    PubMed Central

    Hansma, Paul; Yu, Hongmei; Schultz, David; Rodriguez, Azucena; Yurtsev, Eugene A.; Orr, Jessica; Tang, Simon; Miller, Jon; Wallace, Joseph; Zok, Frank; Li, Cheng; Souza, Richard; Proctor, Alexander; Brimer, Davis; Nogues-Solan, Xavier; Mellbovsky, Leonardo; Peña, M. Jesus; Diez-Ferrer, Oriol; Mathews, Phillip; Randall, Connor; Kuo, Alfred; Chen, Carol; Peters, Mathilde; Kohn, David; Buckley, Jenni; Li, Xiaojuan; Pruitt, Lisa; Diez-Perez, Adolfo; Alliston, Tamara; Weaver, Valerie; Lotz, Jeffrey

    2009-01-01

    Tissue mechanical properties reflect extracellular matrix composition and organization, and as such, their changes can be a signature of disease. Examples of such diseases include intervertebral disk degeneration, cancer, atherosclerosis, osteoarthritis, osteoporosis, and tooth decay. Here we introduce the tissue diagnostic instrument (TDI), a device designed to probe the mechanical properties of normal and diseased soft and hard tissues not only in the laboratory but also in patients. The TDI can distinguish between the nucleus and the annulus of spinal disks, between young and degenerated cartilage, and between normal and cancerous mammary glands. It can quantify the elastic modulus and hardness of the wet dentin left in a cavity after excavation. It can perform an indentation test of bone tissue, quantifying the indentation depth increase and other mechanical parameters. With local anesthesia and disposable, sterile, probe assemblies, there has been neither pain nor complications in tests on patients. We anticipate that this unique device will facilitate research on many tissue systems in living organisms, including plants, leading to new insights into disease mechanisms and methods for their early detection. PMID:19485522

  1. The tissue diagnostic instrument

    NASA Astrophysics Data System (ADS)

    Hansma, Paul; Yu, Hongmei; Schultz, David; Rodriguez, Azucena; Yurtsev, Eugene A.; Orr, Jessica; Tang, Simon; Miller, Jon; Wallace, Joseph; Zok, Frank; Li, Cheng; Souza, Richard; Proctor, Alexander; Brimer, Davis; Nogues-Solan, Xavier; Mellbovsky, Leonardo; Peña, M. Jesus; Diez-Ferrer, Oriol; Mathews, Phillip; Randall, Connor; Kuo, Alfred; Chen, Carol; Peters, Mathilde; Kohn, David; Buckley, Jenni; Li, Xiaojuan; Pruitt, Lisa; Diez-Perez, Adolfo; Alliston, Tamara; Weaver, Valerie; Lotz, Jeffrey

    2009-05-01

    Tissue mechanical properties reflect extracellular matrix composition and organization, and as such, their changes can be a signature of disease. Examples of such diseases include intervertebral disk degeneration, cancer, atherosclerosis, osteoarthritis, osteoporosis, and tooth decay. Here we introduce the tissue diagnostic instrument (TDI), a device designed to probe the mechanical properties of normal and diseased soft and hard tissues not only in the laboratory but also in patients. The TDI can distinguish between the nucleus and the annulus of spinal disks, between young and degenerated cartilage, and between normal and cancerous mammary glands. It can quantify the elastic modulus and hardness of the wet dentin left in a cavity after excavation. It can perform an indentation test of bone tissue, quantifying the indentation depth increase and other mechanical parameters. With local anesthesia and disposable, sterile, probe assemblies, there has been neither pain nor complications in tests on patients. We anticipate that this unique device will facilitate research on many tissue systems in living organisms, including plants, leading to new insights into disease mechanisms and methods for their early detection.

  2. Age-related changes in the tooth-bone interface area of acrodont dentition in the chameleon.

    PubMed

    Dosedělová, Hana; Štěpánková, Kateřina; Zikmund, Tomáš; Lesot, Herve; Kaiser, Jozef; Novotný, Karel; Štembírek, Jan; Knotek, Zdeněk; Zahradníček, Oldřich; Buchtová, Marcela

    2016-09-01

    Chameleon teeth develop as individual structures at a distance from the developing jaw bone during the pre-hatching period and also partially during the post-hatching period. However, in the adult, all teeth are fused together and tightly attached to the jaw bone by mineralized attachment tissue to form one functional unit. Tooth to bone as well as tooth to tooth attachments are so firm that if injury to the oral cavity occurs, several neighbouring teeth and pieces of jaw can be broken off. We analysed age-related changes in chameleon acrodont dentition, where ankylosis represents a physiological condition, whereas in mammals, ankylosis only occurs in a pathological context. The changes in hard-tissue morphology and mineral composition leading to this fusion were analysed. For this purpose, the lower jaws of chameleons were investigated using X-ray micro-computed tomography, laser-induced breakdown spectroscopy and microprobe analysis. For a long time, the dental pulp cavity remained connected with neighbouring teeth and also to the underlying bone marrow cavity. Then, a progressive filling of the dental pulp cavity by a mineralized matrix occurred, and a complex network of non-mineralized channels remained. The size of these unmineralized channels progressively decreased until they completely disappeared, and the dental pulp cavity was filled by a mineralized matrix over time. Moreover, the distribution of calcium, phosphorus and magnesium showed distinct patterns in the different regions of the tooth-bone interface, with a significant progression of mineralization in dentin as well as in the supporting bone. In conclusion, tooth-bone fusion in chameleons results from an enhanced production of mineralized tissue during post-hatching development. Uncovering the developmental processes underlying these outcomes and performing comparative studies is necessary to better understand physiological ankylosis; for that purpose, the chameleon can serve as a useful model

  3. Assessment of the amount of tooth wear on dental casts and intra-oral photographs.

    PubMed

    Wetselaar, P; Wetselaar-Glas, M J M; Koutris, M; Visscher, C M; Lobbezoo, F

    2016-08-01

    Tooth wear is a multifactorial condition, leading to the loss of dental hard tissues. Many grading scales are available to assess the amount of tooth wear, one of which is the tooth wear evaluation system (TWES). A grading scale can be used chairside, on casts and on photographs. The aim was to test whether the grading scales of the TWES, used on casts and on photographs, resulted in comparable scores. In addition, it was tested whether these scales can be used to assess tooth wear reliably on photographs. Of 75 tooth wear patients, sets of casts and series of photographs were obtained and graded. Comparison of the grading on casts and on photographs revealed equal median values and percentiles for both occlusal/incisal grading and non-occlusal/non-incisal grading. The grading on casts and on photographs showed a high correlation for the occlusal/incisal grading and a low correlation for the non-occlusal/non-incisal grading (Spearman's rho = 0·74 and rho = 0·47; P < 0·001). Concerning the grading on photographs, the interexaminer reliability was fair-to-good (ICC = 0·41 to ICC = 0·55) while the intra-examiner reliability was fair-to-good to excellent (ICC = 0·68 to ICC = 0·86) for the occlusal/incisal grading. For the non-occlusal/non-incisal grading, the interexaminer reliability was poor to fair-to-good (ICC = 0·22 to ICC = 0·59), while the intra-examiner reliability was fair-to-good to excellent (ICC = 0·64 to ICC = 0·82). It was concluded that the scores obtained with the grading scales of the TWES on casts and on photographs are comparable. The grading scales can be used in a reliable way on photographs, which is especially the case for occlusal/incisal grading. PMID:27132187

  4. Does Laser Surgery Interfere with Optical Nerve Identification in Maxillofacial Hard and Soft Tissue?--An Experimental Ex Vivo Study.

    PubMed

    Bergauer, Bastian; Knipfer, Christian; Amann, Andreas; Rohde, Maximilian; Tangermann-Gerk, Katja; Adler, Werner; Schmidt, Michael; Nkenke, Emeka; Stelzle, Florian

    2015-01-01

    The protection of sensitive structures (e.g., nerves) from iatrogenic damage is of major importance when performing laser surgical procedures. Especially in the head and neck area both function and esthetics can be affected to a great extent. Despite its many benefits, the surgical utilization of a laser is therefore still limited to superficial tissue ablation. A remote feedback system which guides the laser in a tissue-specific way would provide a remedy. In this context, it has been shown that nerval structures can be specifically recognized by their optical diffuse reflectance spectra both before and after laser ablation. However, for a translation of these findings to the actual laser ablation process, a nerve protection within the laser pulse is of utmost significance. Thus, it was the aim of the study to evaluate, if the process of Er:YAG laser surgery--which comes with spray water cooling, angulation of the probe (60°) and optical process emissions--interferes with optical tissue differentiation. For the first time, no stable conditions but the ongoing process of laser tissue ablation was examined. Therefore, six different tissue types (nerve, skin, muscle, fat, cortical and cancellous bone) were acquired from 15 pig heads. Measurements were performed during Er:YAG laser ablation. Diffuse reflectance spectra (4500, wavelength range: 350-650 nm) where acquired. Principal component analysis (PCA) and quadratic discriminant analysis (QDA) were calculated for classification purposes. The clinical highly relevant differentiation between nerve and bone was performed correctly with an AUC of 95.3% (cortial bone) respectively 92.4% (cancellous bone). The identification of nerve tissue against the biological very similar fat tissue yielded good results with an AUC value of 83.4% (sensitivity: 72.3%, specificity: of 82.3%). This clearly demonstrates that nerve identification by diffuse reflectance spectroscopy works reliably in the ongoing process of laser ablation

  5. Digital image processing. II. In vitro quantitative evaluation of soft and hard peri-implant tissue changes.

    PubMed

    Fourmousis, I; Brägger, U; Bürgin, W; Tonetti, M; Lang, N P

    1994-06-01

    The aim of this study was to evaluate the ability of computer-assisted densitometric image analysis (CADIA) to detect small changes in mineralized and nonmineralized tissues adjacent to dental implants and to correlate these changes with CADIA values. A section of a pig mandible including all soft tissues and in which a hollow cylinder ITI Bonefit implant with an artificial mesial and a buccal infrabony defect was placed was used to obtain pairs of standardized radiographs. Series of radiographs were obtained with exposure times of 0.13, 0.20, 0.44, and 0.53 s. Specimens of mineralized or nonmineralized tissues were placed arbitrarily in the defects before each radiographic exposure. The radiographs were captured through a video camera, digitized and stored in a personal computer. Every radiographic image was then subtracted from a baseline one without any change. The result of the subtraction was evaluated with CADIA. A linear correlation (r2 = 0.99) was found between the bone chips (1-5 mg of dry weight) placed in the mesial defect and the CADIA values. Bone chips in the buccal defect (behind the implant), however, were not detected unless their weight reached 14 mg or more. For conventionally exposed radiographs, it was not possible to recognize soft tissue specimens (1-6 mg), either in the buccal or the mesial defect. However, when "underexposed" radiographs (exposure time: 0.13 s) were obtained, a linear correlation (r2 = 0.80) was calculated for soft tissue specimens in the mesial defect and CADIA values. In normally exposed radiographs, the CADIA system could detect even the smallest change in bone density (bone chip of 1 mg of dry bone weight) and correlated almost linearly with these changes. Provided that the radiographic images are obtained with standardized geometry and normal exposure time, the tissue density changes detected by this system within bone defects represent only mineralized tissue changes. By underexposing radiographs, CADIA may even

  6. Tooth decay - early childhood

    MedlinePlus

    Bottle mouth; Bottle carries; Baby bottle tooth decay; Early childhood caries (ECC) ... chap 304. Ribeiro NM, Ribeiro MA. Breastfeeding and early childhood caries: a critical review. J Pediatr (Rio J) . ...

  7. Replacing a Missing Tooth

    MedlinePlus

    ... majority of patients with clefts will require full orthodontic treatment, especially if the cleft has passed through ... later replacement of the missing lateral incisor. During orthodontic treatment, an artificial tooth may be attached to ...

  8. Effects of a tartar control whitening dentifrice on tooth shade in a population with long-standing natural stain.

    PubMed

    Gerlach, R W; Barker, M L; Hyde, J D; Jones, M B; Cordero, R E

    2001-01-01

    Changing and whitening tooth color in people with long-standing tooth stain without excessive hard tissue abrasion may represent one of the more difficult challenges for whitening dentifrices. An eight-week clinical trial was conducted to evaluate change in tooth color by a silica-based, enamel-safe tartar control whitening dentifrice compared to a marketed baking soda dentifrice control. First, a screening exercise was conducted to identify individuals with long-standing extrinsic dental stain. This exercise targeted adults who reported "stained teeth" and coffee/tea drinking or smoking, but who had no recent history of dental prophylaxis. Targeted subjects were examined for stain (Lobene Index) and tooth shade/color (Vita). A total of 291 adults having extrinsic stain and discolored teeth were enrolled in the study. Subjects were randomized to one of the two treatment groups, and all dentifrice use was unsupervised. Tooth color was measured at 4 and 8 weeks from shade values collected from the 8 incisors, and averages were determined from a linear ordering of the shade guide. A total of 278 evaluable subjects completed the 8-week study. Overall, the tartar control whitening dentifrice group experienced an improvement in color, differing statistically from baseline (p < 0.001) and from the marketed control (p < 0.05). Safety profiles for the two dentifrices were generally similar. Among patients with long-standing extrinsic stain, use of the tartar control whitening dentifrice resulted in superior overall tooth shade and reduced maximum or worst color compared to the marketed baking soda dentifrice control. PMID:11476014

  9. Fracture tooth fragment reattachment

    PubMed Central

    Maitin, Nitin; Maitin, Shipra Nangalia; Rastogi, Khushboo; Bhushan, Rajarshi

    2013-01-01

    Coronal fractures of the anterior teeth are a common form of dental trauma and its sequelae may impair the establishment and accomplishment of an adequate treatment plan. Among the various treatment options, reattachment of a crown fragment is a conservative treatment that should be considered for crown fractures of anterior teeth. This clinical case reports the management of two coronal tooth fracture cases that were successfully treated using tooth fragment reattachment using glass-fibre-reinforced composite post. PMID:23853012

  10. Behaviour of human mesenchymal stem cells on chemically synthesized HA-PCL scaffolds for hard tissue regeneration.

    PubMed

    D'Antò, Vincenzo; Raucci, Maria Grazia; Guarino, Vincenzo; Martina, Stefano; Valletta, Rosa; Ambrosio, Luigi

    2016-02-01

    Our goal was to characterize the response of human mesenchymal stem cells (hMSCs) to a novel composite scaffold for bone tissue engineering. The hydroxyapatite-polycaprolactone (HA-PCL) composite scaffolds were prepared by a sol-gel method at room temperature and the scaffold morphology was investigated by scanning electron microscopy (SEM)/energy-dispersive spectroscopy (EDS) to validate the synthesis process. The response of two different lines of hMSCs, bone-marrow-derived human mesenchymal stem cells (BMSCs) and dental pulp stem cells (DPSCs) in terms of cell proliferation and differentiation into the osteoblastic phenotype, was evaluated using Alamar blue assay, SEM, histology and alkaline phosphatase activity. Our results indicate that tissue engineering by means of composite HA-PCL scaffolds may represent a new therapeutic strategy to repair craniofacial bone defects. PMID:23723157