1,721,510 research outputs found
Biomaterials and bone tissue engineering for the reconstruction of jawbone atrophy
No full textBone tissue engineering by bone grafting is a surgical procedure that replaces missing bone with material from the patient’s own body, using an artificial, synthetic, or natural substitute. Large bone defects and poor bone healing require augmentation to facilitate new bone formation. Long-term prognosis is adversely affected by inadequate bone volume; thus, an adequate three-dimensional amount of bone at the site of implant placement is essential for successful implant therapy.
Bone formation after grafting is characterized by three types of bone growth: osteogenesis, osteoinduction, and osteoconduction. Osteogenesis occurs when vital osteoblasts originate from the bone graft material and contribute to new bone growth. Osteoinduction involves the stimulation of osteoprogenitor cells to differentiate into osteoblasts to begin new bone formation. Osteoconduction occurs when the bone graft material serves as a scaffold for new bone growth that is perpetuated by the native bone. Osteoblasts from the margin of the defect that are being grafted use the bone graft material as a framework to spread and generate new bone. A bone graft material is osteoconductive and osteoinductive, and will not only serve as a scaffold for currently existing osteoblasts, but will also trigger the formation of new osteoblasts, thereby, at least theoretically promoting faster integration of the graft. Numerous methods have been used in Guided Bone Regeneration (GBR). One of the most common techniques involves harvesting and implantating fresh autogenous bone grafts taken from the same patient. However, this is an expensive procedure that requires hospitalization, and has a potential risk of donor site morbidity. To avoid such complications, clinicians have developed the use of biomaterials as substitutes for alveolar bone. Other types of grafts available for the maxilla and mandible include allogeneic, alloplastic, and xenogeneic ones. Autografts are the only grafts that provide osteoinductivity; unfortunately, autografts often have unpredictable resorption, morbidity at the donor site, and limited bone availability, which has stimulated research to find new alternative, for bone tissue engineering
Implantology, orthodontics, orthognathic surgery : an interdisciplinary approach to managing complex treatment plans
No full textA single specialist, often, develops treatment plans according to his own specialized capabilities, expertise and skills, rather than by what the patient actually needs and by the treatment options dentistry can provide. This approach can lead to secondary problems, from esthetical, functional, skeletal, neuromuscular, periodontal and stability stand points. So, to achieve optimal dentofacial results in the treatment of serious orofacial deformities, the approach to patient care should be interdisciplinary. This permits the synergism of each different discipline’s specialized expertise and skills, into the comprehensive protocol of treatment. This presentation shows the importance which have interdisciplinary consultation, communication and collaboration between different specialists
Gli impianti come ancoraggio ortodontico
No full textQuesta valutazione clinica ha l’obiettivo di evidenziare le possibilità, i benefici e i limiti del sistema di ancoraggio scheletrico mediante mini-impianti per i movimenti dentali nelle edentulie parziali gravi ove non è possibile o difficile l’inserimento di fixtures osteointegrate e nel trattamento ortodontico chirurgico. L’uso dei mini-impianti come ancoraggio massimo scheletrico temporaneo permette l’inserimento di un apparecchio ortodontico in qualsiasi posizione e produce facilmente ogni tipo di movimento dentale. Questi sono indicati per la correzione delle malocclusioni dentali e scheletriche degli adulti e per la fissazione intermascellare in chirurgia ortognatica
Algie cranio-facciali di pertinenza odontostomatologica
No full textScopo del lavoro mettere in evidenza l’intima correlazione tra le funzioni: posturale, respiratoria e masticatoria dell’organismo.
Introducendo un concetto tridimensionale nell’approccio diagnostico e terapeutico in odontoiatria, considerando le tre componenti dentale-scheletrica-muscolare; sottolineando l’importanza della kinesiografia (CMS) e dell’elettromiografia (EMG) nell’effettuare una diagnosi corretta come supporto terapeutico e per valutare l’efficacia del trattamento. In passato le limitazioni tecnologiche hanno confinato l’ortodontista ad un protocollo diagnostico e terapeutico basato sull’analisi cefalometrica riferita alla posizione intercuspidale dentale.
Nel corso di questi ultimi anni si è evidenziata l’insufficienza di tale protocollo, in quanto l’ortodontista non può accontentarsi dei soli parametri dentali e cefalometrici, ma deve trattare l’occlusione in base ad un equilibrio funzionale e dinamico di tutte le componenti dell’apparato stomatognatico. Da tempo si conosce l’importanza del ruolo del sistema neuro-muscolare nel determinare i problemi di crescita e sviluppo strutturali della mandibola e della maxilla.
L’ortodontista deve essere un osservatore e un diagnostico non solo delle strutture dentarie, ma anche dello stato nasorespiratorio e posturale del paziente. La conoscenza dell’influenza delle aberrazioni nasali e posturali aumenterà la prevedibilità del trattamento ortodontico, che permetterà all’ortodontista di individuare la cause che contribuiscono alla recidiva ortodontica
Nutrition disorders and cognitive functions in TMD elderly patients
Full text linkObjectives: The aim of this study was to show the destructive effects of abnormal occlusal forces on teeth and on implant supported prostheses in patients with bruxism and temporomandibular disorders (TMD), abnormal habits and other parafunctions, focusing on concepts and the clinical procedures to reduce the potential risk factors for tooth loss and implant failure.
Methods: 40 TMD patients were compared to 40 no-TMD patients in which were inserted 430 implants with the same features as number, size, position, design. Another experimental group of 50 TMD patients treated by prevention protocol was assessed. Were considered type of restoration, cemented or screwed, malocclusion type, smoking, load timing. The heavy force of compression, clenching and grinding, as in bruxism, simultaneously applied strong pressures to the teeth implants, crestal bone, restorations and temporomandibular joints. This was a potential risk factor for crestal bone loss, dental and implant complications.
Results: The 5 years follow-up showed a 58% of soft tissues, bone and prosthetic complications in TMD patients versus a 11% in non TMD patients (P< 0.01). When TMD patients were undergone to occlusal overload prevention protocol, the complications were diminished to 13% (P< 0.01). Increasing the number of implants and reducing cantilevers decreases the stress; using the longest and widest implant possible increases implant/bone surface area and reduces also strain. Also implant design, occlusal table size, the direction, duration and magnification of the forces influences the stress at the crestal bone/implant surface.
Conclusions: Developing treatment plan that control the chronic bruxism through night-guards and an occlusal adjustment protocol to modify the occlusal forces on implants and their restorations, even patients with temporomandibular disorders and bruxism can be candidates for implants. Maintaining a healthy natural and implant dentition in elderly is beneficial from a functional and psyche-social point of view
Temporomandibular joint in orthodonthics
No full textObjective: The aim of this study was to evaluate the functional and neuromuscular changes after surgical-orthodontic treatment of orofacial deformities with TMD. Material and Methods: The study was based on a group of 220 dysgnathic patients. Were evaluated skeletal and dental malocclusion type, TMJ pain, headache, cervical pain, otovestibular symptoms and by electromyography and kinesiography the muscular activity and the mandibular movements. Results: The post-treatment results showed that almost all craniomandibular symptoms were significantly reduced postoperatively above all muscular spasms (96%) and headache (61%), (P<0,01); mandibular kinesology (81%) was improved (P<0,01). Also cervical pain, otovestibular and postural symptoms seem to benefit from treatment. Conclusion: Even if preoperatively asymptomatic patients with TMJ problems after surgery (8,8%) have resulted (P<0,1), the combined surgical-orthodontic treatment may be of a great benefit in the correction of severe orofacial deformities associated to temporomandibular disorders
Computer aided design/computer aided manufacturing bone grafts for reconstruction in jawbone atrophy
Full text linkAim: The aim of this work is firstly to verify the optional mechanical and biological properties of HA in vitro and in vivo, comparing to other synthetic materials. Secondly the CAD/CAM technique using porous HA scaffold was evaluated to estimate its real efficacy with clinical and radiological assessments.
Materials and Methods: Inclusion criteria selected for the current study are 1) histological evaluation of the effective biocompatibility and osteoconductivity of porous HA in vivo and in vitro 2) evaluation of the mechanical properties of HA in relation to its porosity 3) compared evaluation of biological and mechanical properties between several biomaterials in order to assess whereas HA is preferable in relationship to different clinical situation 4) clinical and radiological evaluation of the precision of the CAD/CAM technique.
Results Among the synthetic materials, hydroxyapatite has proved excellent osteoconductivity and biocompatibility in vitro and in vivo comparing to other biomaterials, porous hydroxyapatite (HA) is a more readily resorbable and more osteoconductive material than dense HA, however the strength decreases exponentially with the increase of the porosity. Mechanical tests showed that fabricated HA scaffolds with pore diameters ranging from 400 to 1200 microns had compressive modulus and strength within the range of human craniofacial trabecular bone; this implies that they can be easily used for bone regenerative rehabilitations.
Conclusion: Several studies in vivo l-rave evaluate optimal clinical and radiological results using HA scaffold as grafts before implants position even after several months on both human mandibula and r:raxilla. In conclusion, using CAD/CAM technique for HA scaffold could increase grafts stability and reduce surgical operative time
Temporomandibular joint symptoms before and after orthognatic surgery
No full textAim: The aim of this study was to evaluate temporomandibular joint (TMJ) symptoms, the functional and neuromuscular changes after surgical-orthodontic treatment of orofacial deformities with temporomandibular dysfunction (TMD).
Material and Methods: The study was based on a group of 420 dysgnathic patients. Were evaluated skeletal and dental malocclusion type, TMJ symptoms, headache, cervical and neck pain, otovestibular symptoms. Electromyography and kinesiography were used to assess the muscular activity and the mandibular movements.
Results: TMJ symptoms in low and normal angle mandibular retrognatism patients have improved (p<0,01). The post-treatment results showed that almost all craniomandibular symptoms were significantly reduced postoperatively above all muscular spasms (96%) and headache (61%), (P<0,01); mandibular kinesology (81%) was improved (P<0,01). Also cervical pain, otovestibular and postural symptoms seem to benefit from treatment. Even if preoperatively asymptomatic, patients with TMJ problems after surgery (8,8%) have resulted (P<0,1). In preoperatively asymptomatic patients who developed TMJ symptoms after surgery, the highest incidence was found in high angle patients with severe mandibular retrognatism, treated by bimaxillary surgery.
Conclusion: The combined surgical-orthodontic treatment may be of a great benefit in the correction of discrepancies in occlusion and maxillo-mandibular relationship in the severe orofacial deformities associated to temporomandibular disorders. Conversely orthognatic surgery can produce TMJ symptoms by changing the position of the mandible and the maxilla with regard to each other and therefore the position of the condyle in the glenoid fossa. Mandibular ramus, osteotomies have a direct influence on this position, whilst in maxillary osteotomies the influence is indirect because of autorotation
Qualità delle immagini diagnostiche e rischi di esposizione : la Tac Cone Beam
No full textLa TAC Cone Beam (CBCT) rappresenta sicuramente un’importante innovazione nel campo dei sistemi di acquisizione tomografici e delle ricostruzioni volumetriche. Inizialmente applicata in angiografia e in radioterapia, la tecnologia Cone Beam CT ha trovato negli anni recenti un forte sviluppo in ambito odontoiatrico. Specialmente con la messa a punto di software specifici per la ricostruzione 3D e hardware in grado di gestire la mole di dati da elaborare ha permesso una riduzione dei costi di acquisto delle apparecchiature e una conseguente maggiore diffusione. La CBCT applicata al campo dentale ha dato il via a dei sistemi dedicati avendo come risultato un’aumentata qualità dell’imaging con una notevole riduzione della dose di radiazioni data al paziente, tali da poterla usare anche nei bambini con particolari patologie. Infatti la Cone Beam nei confronti delle TC più moderne presenta dosi da 5 a 20 volte inferiori a parità di volume irradiato (IAEA - Agenzia Internazionale per l’Energia Atomica ). Il sistema CBCT permette la creazione di immagini su tutti i piani nello spazio: assiale, coronale, sagittale, obliquo o addirittura ricostruzioni seguendo una linea curva attraverso un processo denominato Multi Planar Reconstruction (MPR). Gli apparecchi radiologici Cone Beam emettono fasci di raggi X che hanno la forma conica anziché a ventaglio come gli apparecchi usati per la tomografia computerizzata convenzionale (CT o MSCT). L’esposizione è a radiazioni pulsate e permette di acquisire le immagini base con un’unica rotazione per tutto il FOV (field of view) selezionato. Successivamente è possibile tramite software elaborare i dati acquisiti trasformandoli in un unico volume il cui elemento essenziale è il voxel (pixel 3D). Più piccolo è il voxel più è definita l’immagine Cone Beam. Da questo volume si possono ricalcolare tutte le immagini volute con l’orientamento a scelta senza distorsioni – i voxel infatti sono isotropici (di ugual misura nelle tre dimensioni dello spazio)
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