Objective. The objective of this study is to test the efficacy of the biodegradable mesh as an alternative fixation device to the titanium mesh for support of onlay particulate, bone and cancellous, marrow (PBCM) grafts. Two parameters were evaluated: (1) Bone graft volume maintenance; and (2) Calcified tissue surface area and distribution. Methods. 12 New Zealand white rabbits were used and divided equally into two groups. In both groups, endochondral, cancellous bone graft was harvested from the anterior ilium. The bone graft was then compressed and placed as an onlay onto the lateral aspect of the mandible using two chambers for each animal. In the control group, the chambers were made of titanium, however in the test group the chambers were made of poly L-lactide, polyglycolide and trimethylene carbonate mesh (Inion GTR(TM) Finland), and thereafter the chambers were fixed to the mandible. The animals were then sacrificed after eight weeks postoperatively, and then Micro-CT imaging was performed for the entire sample in order to determine the total volume of calcified tissue present under each chamber. In addition, Histologic sections were obtained from each chamber, and thereafter stained using Toluidine blue and Von Kossa for the purpose of histomorphometric analysis in order to determine the calcified tissue surface area. Results. When comparing the data from both the titanium (Ti) and the biodegradable mesh (PLA) groups, Micro CT analysis showed no significant statistical difference (P-value = 0.546) with regard to the percentage of bone found under the chambers (Ti 15.0% and PLA 13.83%). Interestingly, neither did the histomorphometric analysis show any significant statistical deference (P-value = 0.8272) with regard to the percentage of calcified tissue surface area (Ti 16.86% and PLA 16.17%). Moreover, this calcified tissue was also found to be evenly distributed in both groups. Conclusion. Biodegradable mesh made of poly L-lactic and polyglycolic acid copolymers appears to be an appropriate alternative to the Ti mesh for support of PBCM bone grafts. However, further clinical trails should be conducted to confirm these findings.

This study explores the effects of manipulating vocal loudness and speech rate on voice onset time (VOT) in normal hearing children and two children with cochlear implants (CIs). 15 normal hearing participants and two participants with CIs produced all six stop consonants in the phrase “It’s a Cod again” while speaking normally, softly, loudly, slowly, and quickly. Consonants were grouped into voiced and voiceless categories for comparison. Results indicated that the group of normal hearing children produced longer VOTs for voiceless stops than voiced across all conditions. When speaking loudly or quickly, VOT values were shorter than at normal levels. When speaking softly or slowly, VOT values were longer than at normal levels. The two children with CIs performed in a similar manner to the normal hearing group; however, VOTs produced by the six-year old participant were consistently longer than those of the normal hearing group across all conditions. / Speech-Language Pathology

No description available.

El aumento de tratamientos prostodónticos implantosoportados para restituir la perdida de dientes supone que la cirugía de implantes sea una actividad habitual en las clínicas odontológicas, por ello la operación de colocación de los implantes debe garantizar el éxito teniendo en cuenta unas recomendaciones importantes entre las que destaca evitar el calentamiento excesivo del hueso durante la perforación del lecho óseo que puede provocar desnaturalización de proteínas y necrosis ósea.También es necesaria la máxima biocompatibilidad en la prótesis ha realizar sobre los implantes de titanio debido a la corrosión galvánica que existe por el contacto de metales de distinta naturaleza dentro de un medio conductor como es la saliva, para evitar esto se usa titanio como metal para prótesis, pero existen dificultades de manipulación y de unión con la cerámica que dificultan su aceptación clínica generalizada.El primer tema de investigación fue el estudio in vitro del control de la temperatura del hueso durante el fresado del lecho óseo. Se fabricaron tres fantomas para valorar las diferencias que pueden existir entre diversos sistemas impulsión de suero fisiológico y de irrigación del lecho óseo en función del diseño de las fresas. Se observó que las condiciones en que el suero fisiológico va desde la botella hasta la zona quirúrgica influyen en su calentamiento, encontrando diferencias estadísticamente significativas entre las bombas de impulsión usadas, no se encontraron diferencias estadísticamente significativas entre fresas cortas y largas con irrigación interna cerca de la punta de la fresa. También se valoró in vitro la eficacia de tres sistemas de irrigación (externa, interna en la base de fresa e interna en la punta de la fresa) para hacer llegar un volumen de suero adecuado en el fondo del lecho fresado y su influencia en la evolución de la temperatura del hueso fresado. Se observó que la irrigación interna cerca de la punta de la fresa obtuvo los mejores resultados con diferencias estadísticamente significativas respecto los otros sistemas de refrigeración.El segundo tema de investigación fue valorar la adhesión entre las estructuras protésicas fabricadas en diversos tipos de titanio y algunas cerámicas cocidas sobre él, mediante ensayos mecánicos de flexión en tres puntos. Un estudio preliminar permitió valorar si las diferencias entre el titanio grado 2 y el grado 4, que tienen propiedades mecánicas y químicas distintas, podían influir en la unión con las cerámicas y en su comportamiento mecánico. A partir de los resultados se definió el grado de titanio y el tratamiento superficial que optimiza la adhesión con las cerámicas para realizar un segundo estudio de comparación entre titanio colado y mecanizado. Para el estudio preliminar se fabricaron unos modelos de simulación con distintas combinaciones de titanio y cerámicas, que se ensayaron mecánicamente y se observaron con microscopio electrónico para analizar las fracturas. En este estudio obtuvo mejores resultados de resistencia a la flexión la combinación de titanio grado 4 y cerámica, pero se observó que era mejor la adhesión entre el titanio grado 2 y la cerámica debido a la mayor micro-rugosidad superficial del titanio grado 2.La comparación entre titanio colado y mecanizado se realizó de acuerdo a la Norma Europea EN ISO 9693:1999 publicada en español en septiembre de 2.000. Se usaron combinaciones de Cr-Ni y Cr-Co con cerámica a modo de control negativo.Los valores de resistencia a flexión del titanio colado y mecanizado no presentaron diferencias estadísticamente significativas entre ellos, además superaron ampliamente los mínimos exigidos para la aplicación clínica de una combinación de materiales.

Polymeric surface modification has become an important technique over the last few decades in many areas, including medicine. It provides improved surface properties for specific applications without altering the bulk of the material. Graft copolymerisation is one technique which allows an existing polymer to covalently immobilise different monomers with or without new functional groups. Some polymeric implants are used as hard tissue substitutes for bone. However, the surface of the implant is often deficient in binding with hard tissue. Since phosphates are one of the building blocks of hydroxyapatite [Ca10(PO4)6(OH)2] or HAP, which is the main inorganic composition of bone, phosphate groups may be utilised on the surface of polymeric implants. This has the possible effect of directing bone formation at the material/tissue interface. The radiation-induced grafting of MOEP (methacryloyloxyethyl phosphate) onto ePTFE (expanded PTFE) has been carried out by a simultaneous irradiation technique in the presence of solvents. Two solvents and one mixed solvent system (in this study: methanol, MEK and a mixture of methanol, water and DCM) were used to dilute MOEP under various monomer concentrations and experiments were carried out using two different dose rates. The modified surfaces were characterised using the weight increase, XPS, FTIR-ATR, SEM, and contact angle measurement. The degree of grafting was found to be proportional to the monomer concentration but did not depend on the dose rates used. However, the grafting yield was strongly dependent upon the type of solvent used. The grafting decreased in the order: mixed solvent system » MEK > methanol. In addition, different morphologies of grafting were observed from SEM images depending on the solvent used. The samples prepared in methanol had a smooth morphology, whereas the samples obtained in MEK with a monomer concentration of greater than or equal to 10% w/v and with a mixed solvent system, had globular morphologies. A combination of in vitro tests onto three types of grafted membranes was performed (in this study: simulated body fluid (SBF), protein and cell attachment tests). Structure, composition and morphology of the calcium phosphate growth on the samples after 7 days of immersion in SBF were studied by SEM/EDX and FTIR-ATR. It was found that the growth of CaP onto the sample with low surface grafting (24%) and with a smooth morphology, was carbonated HAP. With the samples with higher grafting and globular morphologies, the inorganic minerals formed were less and had not HAP stoichiometric composition but were presumably Brushite and Octacalcium phosphate (OCP). The amount of protein adhesion in BSA solution (with 24 hours of immersion) and serum solution (with 1 hour of immersion) were determined gravimetrically and by XPS. In addition, the protein layer was investigated using FTIR-ATR. It was found that protein adsorption was highest on the surface with high grafting (100%) possibly due to the electrostatic interaction. Human osteoblast-like cell attachment and cell morphology (both after 3 hours) were examined by cellular protein synthesis assays and SEM. Cell attachment and morphology were also better on the samples with high grafting yield compared to that of low grafting, which follows the results of protein adsorption. The different in vitro tests do not agree, however, in all cases better bioactivity was found for grafted samples than that for untreated samples. This research emphasises the importance of using a series of in vitro tests to evaluate the bioactivity of materials. Although it is not clear as to what the optimum grafting conditions are at this stage, grafting of phosphate-containing monomer onto ePTFE has significantly improved the bioactivity in vitro.

Objectives: To compare the osseointegration of conventionally and immediately restored tapered implants in a split-mouth animal model, and to compare different methods of analysis for measuring osseointegration. Materials & Methods: Twenty tapered implants were placed in the posterior mandibles of ten sheep, three months after premolar extractions. Ten control implants were placed and were restored after three months submerged healing. Ten test implants were placed on the contralateral side at this time and immediately restored. Animals were sacrificed after a further three months healing. Resonance frequency analysis (Implant Stability Quotient, ISQ), and standardized radiographs were taken at all stages. Alveolar bone height relative to the implant shoulder was measured on digitized radiographs. Histomorphometric and micro-Computed Tomograph ([mu]CT) morphometric analysis for Bone-to-Implant Contact (BIC) and Bone Density (BD) were performed. Radiographic, stability and morphometric measurements were compared statistically. Results: Only three (30%) of conventionally restored and two (20%) immediately restored implants survived (p = 0.74). Mean crestal bone level after three months loading differed significantly (control 5.3 � 0.9 mm versus test 0.9 � 1.3 mm; p = 0.02). Control implants lost more crestal bone over three months than test implants but this was not statistically significant (3.5 � 1.0 mm versus 0.7 � 1.0 mm; p = 0.06). The test group showed a higher mean ISQ value (85.4 � 6.9) compared to the control group (72 � 14.4; p = 0.349). Both groups showed a slightly reduced stability during the loaded period. This was more marked for the test group but not statistically significant (-0.5 � 3.8 ISQ versus -4.35 � 6.6 ISQ; p = 0.8). A statistically significant negative correlation was found between the loss of crestal bone and ISQ with loading (Pearson�s coefficient of correlation r = -0.473 p = 0.026). Both groups showed a statistically significant difference in BIC for both histomorphometric analaysis (HMA); p = 0.039 and [mu]CT morphometric analysis; p = 0.013. When the two forms of morphometric analysis were compared, HMA and [mu]CT morphometric analysis differed significantly for both BIC (p = 0.05) and BD (p = 0.048). However, a statistically significant correlation was found between the two measuring techniques, for both BIC (r = 0.335 p = 0.013) and BD (r = 0.439 p = 0.01). Conclusions: The placement of wide-bodied 3i Osseotite NT[TM] tapered implants into sheep mandible resulted in high failure rate regardless of the loading protocol. The sheep mandibular model may be inappropriate as a model for evaluation of immediate loading, and to test implants which are designed for soft bone. Further investigations are needed to look into the variations in bone microstructure along with their impact on the mechanics of implant-bone union. Although a statistically significant difference was found between the two measurement techniques, a positive correlation was found between HMA and [mu]CT morphometric analysis suggesting non-invasive methods may have a potential in assessing osseointegration. Further research is required to optimize the variables in [mu]CT analysis, such as, voltage, filters, and thresholding to minimize artifacts and to maximize bone contrast when titanium implants are present.

Objective: The aim of the study was to evaluate the clinical outcomes of oral implant treatment provided at the School of Dentistry, University of Otago from 1989 to 2005. Methods: Oral implant patients (n=320) with 586 implants were identified and invited to attend for a clinical examination. Implant demographics of all the patients were extracted from the files. Implant demographics of the examined and unexamined patients were compared to assess if the examined patients were representative of the total group. One hundred and three patients with 214 implants agreed to attend for an examination. In the clinical examination full mouth plaque scores, probing depths, bleeding on probing and suppuration were measured. In addition, around implants recession and width of keratinized gingiva were also recorded. For the radiographic examination, baseline radiographs and radiographs taken at the time of examination were digitized and compared to measure the amount of bone lost or gained around implants using NIH Image J software. Results: There were equal numbers of males and females with a mean age of 46.3 � 15 years at the time of implant placement. The smoking history at the time of examination was recorded, 56% of the patients were non-smokers, 37% former smokers, and 7% were current smokers. More than half of the implants (56%) were placed in the anterior region. Based on the type of implant system, 79% were Branemark implants, 10% Straumann, 6% Southern implants and 4% were unknown. Most of the patients (64%) had implant-supported crowns, 19% had fixed denture prostheses, and 17% had implant-supported overdentures. The overall implant survival rate was 97.7% with five implants lost (2.3%) and 8 implants treated for peri-implantitis (3.8%). The mean PD around implants was 2.3mm (SD 0.6mm), mean recession was 0.5mm (SD 0.8mm) and mean attachment level of 2.8mm (SD 0.9mm). Probing depths [greater than or equal to] 4mm with BOP were recorded around implants in 8.9% of patients. The mean full mouth plaque score was 30% while mean plaque score around implants was 15.9%. The average bone loss around implants was 0.3mm (SD 0.8). Maximum bone loss observed was 2.9 mm. Conclusion: The prevalence of peri-implant inflammation and implant survival rates in this group of patients appeared comparable to that reported in the literature. The prevalence of peri-implant lesions was low in the group of patients examined.

Bibliography: leaves 193-206. / xiii, 206 leaves : ill. (chiefly col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / This thesis investigates the effect of femoral stem surface roughness and a collar on the fixation of cemented hip hemi-arthroplasty femoral stems in an in vivo sheep model up to nine months following implantation. Plain radiography, micromotion between prosthesis and bone during mechanical testing and histology are used. / Thesis (Ph.D.)--University of Adelaide, Dept. of Orthopaedics and Trauma, 1997?

Doctor of Philosophy (PhD) / An in-depth, longitudinal study of the speech and oral language development of eight infants with a profound hearing loss who receive early interventions focused on developing their auditory, speech and oral language capacity is presented in this thesis. Infants were tracked for two years, during the period when they are changed from a hearing aid to a cochlear implant. All infants in this study had their hearing loss identified early and were fitted with hearing aids between 1 and 7 months of age and received their cochlear implant between 8 and 16 months of age. They attended a number of different auditory-verbal early intervention programs (depending on where they lived) all of which focused on developing speech and language skills through listening. Attendance at their particular early intervention program at least once a week was in addition to weekly attendance the Sydney Cochlear Implant Centre for therapy and audiological services. A broad range of measures has been used to track the infants’ acquisition of oral language skills, including measures of communicative intention, pre-speech and speech development, and oral language development. Despite a wide range of individual differences across the group of infants, the results suggest some general trends. In the area of communicative intent most infants followed typical development patterns in terms of both the types (e.g. requesting, answering etc) and forms (gestural, vocal, verbal) used, but they showed delays in their frequency of usage of these types and forms. For speech development the infants demonstrated typical speech skills by 18-months post-cochlear implantation in the areas of consonant inventories, severity of phonological involvement (speech intelligibility) and phonological process development, but they showed delays in vowel and consonant acquisition. Finally, for language development the infants were delayed relative to typical development at 18 months post-implantation. The findings support and extend previous studies which have demonstrated the benefits of early intervention for communication development in infants with hearing loss (Calderon & Naidu, 2000; Mayne, Yoshinaga-Itano & Sedey, 2000; Moeller, 2000; Yoshinaga-Itano & Apuzzo, 1998). However, the delays in the oral communication skills of the infants in the current study suggest that more intensive long-term intervention is required if the infants are to attain typical oral speech and language development. The findings capture the complexity of early oral language development, which has been lacking in previous studies of infants with significant hearing loss, receiving a cochlear implant (Dettman, Briggs, & Dowell, 2005; Houston, Ying, Pisoni, & Iler Kirk, 2003; Schauwers, Gillis, Daemers, De Beukelaer, & Govaerts, 2004). The present data also provide some limited support for earlier implantation, that is, before 12 months of age, as the infants made little progress in oral language development while using hearing aids. The reduced amount of auditory signal available to them prior to implantation may be the determining factor in their inability to follow typical rates and patterns of development. However, rates of development with the implant were not straightforward and further research on this population is needed. Universal neonatal screening programs for hearing loss will potentially provide a larger population of early identified infant for future research. This will create the opportunity for large scale, prospective, longitudinal, studies examining the acquisition of speech and oral language development. Limitations of this study, tracking the early stages of speech and language development over a two year period are identified. Future studies are needed to follow the infants for a longer time to determine if their rate of development is sufficient for them to catch up in areas of delay and maintain their performance in areas where they match their typically developing peers.

Thesis (M.S.)--University of Texas at El Paso, 2007. / Title from title screen. Vita. CD-ROM. Includes bibliographical references. Also available online.